INTRODUCTION
I recent years ornithologists working with passerine birds have
grown increasingly aware that they are dealing with a top-heavy
classification. Current taxonomic methodology, while permitting
vast refinement at the species level, has added nothing to our under-
standing of the higher categories. Some families are still but vaguely
defined, and we know little about the inter-relations of over 60 families
in the suborder Oscines (song birds), an assemblage comprising nearly
half of all bird species. The situation, alluded to by Mayr and
Vaurie (1948: 238), is most serious as it affects the ornithological
contribution to the history of world faunas. This contribution can
only be a misleading one so long as the arrangement of these families
into a phylogenetic tree remains unaccomplished. With few excep-
tions, the relationships of groups occupying widely-separated faunal
regions may only be guessed at now.
The present investigation was undertaken to clarify the relation-
ships of these higher categories of Oscines and to construct a phylogeny
by applying the methods of comparative anatomy. Nearly a thousand
specimens (over 600 species) from virtually all currently recognized
oscinine families were dissected, and the taxonomic arrangement is
based mainly on several independent lines of anatomical evidence in
the head region, with particular attention to jaw musculature. Thou-
sands of additional skulls and skins were studied, and the classification
is not only supported by the external characters normally used in
taxonomy but by such non-morphological characters as behavior.
This survey has made nearly exhaustive coverage of the oscinine
species in the spirit collections of the United States National Museum,
American Museum of Natural History, and Chicago Natural History
Museum. A few specimens were borrowed from the Museum of
Vertebrate Zoology, from the British Museum (Natural History), and
the Dominion Museum (Wellington, N.Z.). For use of, or help in
obtaining, specimens, I am indebted to Alexander Wetmore, Herbert
Friedmann, Ernst Mayr, Dean Amadon, Charles O'Brien, Frank A.
Pitelka, Keith L. Dixon, Richard Meinertzhagen, David Lack, Francis
C. Fraser, Robert A. Falla, Karl Plath, Albert J. Franzen, Thurston
Wright, Karl P. Schmidt, and D. Dwight Davis. Mayr, Areadon,
and Davis also read the manuscript and offered suggestions, as did
James L. Peters, John T. Zimmer, James P. Chapin, Jean Delacour,
Josselyn Van Tyne, Alfred E. Emerson, Sewall Wright, and Austin L.
Rand. Harvey I. Fisher and Emmet R. Blake gave valuable sugges-
tions and advice. The writer alone is responsible for the classification.
This paper is offered in partial fulfillment of the requirements for the
Ph.D. degree in the Department of Zoology, University of Chicago.
HISTORICAL
What any discipline is; or even what it may become, is largely
hafiuenced by its past history. The refinement of the classification of
passefine birds at the species level is a direct outcome of the acceptance
of the museum study skin as the ultimate working unit of taxonomy,
and this has virtually limited diagnosis to external characters. True,
Mfiller (1845) early differentiated between the oscinine (song) birds
and suboscinine birds on the basis of syringial musculature, and
anatomy had its brief vogue under Garrod, Gadow, Ffirbringer, and
others, but none of them attempted the anatomical diagnosis of
passerine families. Nor was this vogue in any way widespread;
before it and during it, the taxonomy based on skins flourished and in
the end may have brought about the early decline of comparative
anatomy. Scientists employed by museums were increasingly oc-
cupied with describing new species, and it was more productive to
mine ornithological knowledge where the vein was rich. Some
museums ceased eventually to collect anatomical material.
The universal acceptance of the bird skin is readily understandable.
Such a bird specimen with complete data is adequate to diagnose a
new species. It shows perfectly the distinctive features of the
plumage, feet, and bill, and it permits counting and measuring flight
feathers. Species systematics based on skins was invaluable (Mayr,
1942) in demonstrating evolutionary mechanisms. There is, thus, no
justification for the extreme view that ornithologists "save the skin
and throw away the characters." An anatomical specimen in alcohol
is sodden, patternless, tedious to study, difficult to store. It is only
regretted that anatomical work at a higher level did not keep pace
with the phenomenal growth at the species level. But species could
be arranged on the basis of common external characters into genera
and these genera into families, so anatomy seemed superfluous.
However, it was less easy .to arrange families, thus contrived, into
larger groups within the order, because the end product of this method
is a jumble of miscellaneous families that cannot easily be related in a
phyletic scheme.
It was deeply ingrained in ornithological opinion that anatomy
could yield results only after years of tedious dissection, and too often
osteology was taken up.by systematists who hoped to by-pass the
musculature. These static morphological comparisons of bony skull
processes and muscle scars by workers who apparently made no
attempt to understand their adaptive r6le led to much erroneous
conjecture. The musculature, largely responsible for these features,
is more basic. It is also more conservative than the misleading
osteological "characters" (often the expression of only minor muscle
slips), and it falls into an easily recognizable hierarchy of pattern.
METHODS AND JSSUMPTIONS
,4 Working Hypothesis.--The body of this paper necessarily details
the characters of the oscinine groups and would be hard to follow
without an understanding of my working hypothesis and assumptions
which are presented below.
This project was launched five years ago in the spirit of functional
anatomy, and it was recognized at once that food-niche specialization
has played a dominant r61e in passefine evolution. First, the degree
of individual variation in jaw musculature was studied for a number of
common species, using from 6 to 10 specimens, without finding the
slightest deviation from the typical muscle pattern. Once the neg-
ligible degree of anatomical variation within the species was estab-
lished, it was considered basic to phylogenetic work to deter-
mine the extent of variation occurring with diet differences among
the species of an entire family. The blackbird family (Icter-
idae), selected for this initial study (Beether, 1951a), embraces mem-
bers which exploit virtually all food-niches occupied by passerinc
birds. Yet, through extremes of skull modification including thick-
billed finch types and thin-billed insect- and nectar-adapted types, a
single pattern of jaw musculature persists in the family. This pattern,
characterized by the highly pinnate adductors found in finches, helps
relate the blackbirds to buntings, while similar features in the latter
relate them to the wood warblers. Each of these higher groups in
turn exhibits a similar constancy of pattern within itself.
An exploratory survey of the Oscines early in 1947, using a few
characters additional to jaw musculature, suggested the feasibility of
similarly diagnosing all oscinine families. Moreover, with the added
assumption that muscles with parallel fibers are phylogenetically
primitive, and pinnate muscles advanced (Beether, 1951a), it was
possible to arrive at a basic morphological type from which all other
oscinine types could be derived--so the means existed for linking the
families in a phyletic scheme. This basic type, simple in structure and
function, is ideally realized in the living Old World warblers, the
Sylviinae (figure 2)--a group with a pattern of parallel-fibered
muscles, and which, on distributional evidence, may date back to the
Cretaceous. Then we face the final assumption, viz., that a phylogeny
may be derived from a morphological tree of relationships, and we can
only point out that passefine fossils to date fit well in living families.
The essential uniformity of the parrots, the trogons, and other pan-
tropical non-passefine families today implies early origin before the
tropical biota severed tenuous northern connections and retreated to
the equatorial regions of Old and New Worlds. In contrast, except
for certain eurythermal world-wide families like swallows, passerines
are represented by entirely different groups in Old and New World--
groups that evidently evolved in isolation from each other after the
northern exchange corridor was closed. It appears that this order,
comprising perhaps the only generalized insectivorous birds at the
time flowering plants evolved in the Upper Cretaceous, was in a
position to evolve forms to fill the many new niches provided by this
plant group. The impact of this abundant new food source, which
also conditioned the origin of many insect groups, resulted in a radia-
tion completely out of proportion to that in other orders, so that the
numerous passefine families do not show the great morphological
disjunctions characteristic of non-passefine ones.
Judging from anatomical and other characters, the insectivorous
American vireos (Vireonidae) are apparently descendants of the Old
World insect-eaters that were cut off when the northern exchange
corridor submerged or became too cold. Subsequently, the vireos
gave rise to the entire nine-pfimaried American assemblage. They
appear directly ancestral to the fruit-eating tanagers and the mainly
insectivorous warblers, each of which evidently evolved. a nectar-
adapted line and several finch lines convergently (Beether, 1951b).
In a parallel manner the Sylviidae evolved a similar assemblage
adapted to the plant-niches of the Old World, and more recent inter-
change between these assemblages has been in direct relation to the
ability of species to cross the northern cold barrier. This is taken as
evidence that the Oscines existed only as insect-eaters when the
Vireonidae became isolated in the New World, and we may be justified
in assuming that this happened before the origin of flowering plants or
about the same time. Fossil evidence from passefine birds is noto-
riously poor, but Milne-Edwards (1867) lists a titmouse and a starling
from the Upper Eocene of France (hardly primitive types) and there
is evidence of early origin from Suboscines to be given later.
Evolutionary Rates and Taxonomic Categories.--The tenet that only
characters not under the influence of adaptation may be used in
taxonomy has been badly misinterpreted. Wright's "genetic drift"
and gene linkage provide a theoretical basis for the appearance of but
a small proportion of non-adaptive characters at the population
level, and Davis (1949: 86) doubts the occurrence of Simpson's
inadaptive stages. So do I. In fact, a taxonomist separating
species of wood warblers, for example, is engaged in classifying adapta-
tions. What makes taxonomy possible is the existence of different
levels of adaptation, reflecting that the parts of an organism are
evolving at different rates (Simpson, 1944). Each of these warbler
species has essentially the same pattern of hind limb musculature, a
character holding so far as investigated for the entire order Passeri-
formes. Each has the same pattern of syringial musculature, a
character embracing the entire suborder Oscines--as well as the jaw
muscle pattern which is the hallmark of the Parulinae. Each of
these characters is adaptive. They differ in being progressively less
deep-seated, the jaw muscle pattern reflecting the diet specialization
that resulted in a new group. The fact that a jaw muscle pattern
holds for a particular oscinine group (family) gives it taxonomic value
at the family level. The more conservative syringial musculature
provides subordinal characters which are safeguards against errors
due to external convergence. It prevents classifying, for instance, a
tyrannid flycatcher as a muscicapid.
The Convergence Hazard.--That jaw muscle patterns are a clue to
phylogenetic relationships at family level had to be determined by
testing them against characters of known value. The reality of most
oscinine families is unanimously recognized by ornithologists, and the
muscle patterns not only hold for these large groups but permit the
assignment of those rather rare species whose family affinities were
uncertain. Such species often show external convergence with groups
to which they do not belong and, where convergent species occupy the
same range, the most expert taxonomists may have difficulty in
resolving a complex on the basis of external characters alone. The
species of the "family" Coerebidae appear to be nectar-adapted
warblers and nectar-adapted tanagers (Beecher, 1951b), and the sub-
families of finches, arising from warblers and tanagers, will be shown
to be convergent. A more complicated case of convergence at
genetic level was indicated in the American orioles (Beecher, 1950).
In classifying the oscinine families, one must face the practical task
of assigning species whose affinities cannot be decided on external
characters alone (Mayr and Amadon, 1951). The anatomical placing
of such convergent species as exist in spirit collections was not hard
and is not highly subjective. This is because the reality of the groups,
as diagnosed by internal as well as external characters, is a matter of
fact, however much one may question their arrangement into a
phyletic scheme.
At the same time precautions were taken against being misled by
convergence in the jaw muscle patterns which, rarely, approach
each other without indicating near relationship. As a safeguard,
several additional characters, forming completely independent lines
of evidence, were studied in all specimens and are figured. The relief
pattern of the horny palate was greatly valued by Sushkin (1927: 3)
for diagnosing large groups of birds. It shows great conservatism and
is often useful in linking related groups (Beecher, 1951b). Like the
musculature it is more complex in advanced groups and affords
further opportunities for group distinctions between convergent groups
forming terminal twigs like the finch groups. We now know that the
bill itself may often show convergent resemblance in unrelated groups,
LACIAYMAL FREE" ''WIND
~DOUBLE
F. USE. TRUNCATE'
FIOURE I. Characters of the ectethmoidal plate.
but a palate facies persists in a family--even through the varied bills
of icterid genera (Beecher, 1951a)--so the character is useful when
supported by collateral evidence. Operculation of the nostril and
rictal bristles vary adaptively in a group as does the tongue, and
therefore these must be weighted accordingly. The free lacrymal
(figure I), constant for whole assemblages of families, may occur in
scattered individual species of other groups, possibly as an adaptation
to forward vision. The ectethmoid foramen (figure I), conducting the
olfactory nerves through the bony plate separating the orbital and
nasal cavities, is always single in primitive stem groups. In more
advanced groups, particularly in the superfamily Sylvioidea, a general
tendency toward pinched or double foramina is noted, and this is also
constant in a group. The ectethmoid itself may be unusually winged
or truncate.
The Real Problem in the Oscines.--The striking anatomical uni-
formity of all oscinine families, except with regard to the feeding
mechanism, presented a peculiar problem. We had constant char-
acters tying the families together (the hind limb and syringial muscu-
lature) and characters for distinguishing the families fairly well. But
we lacked characters for showing the relation of the families to each
other. The jaw muscle patterns with a few additional characters of
head and bill do this--and only because they reflect adaptive differ-
ences in food preference between families. If we may judge from the
present diet of most families, their entire evolution is the result of
selection pressure acting on primitive insectivorous stocks arising
from the stem Sylviidae--pressure to fill the new food-niches provided
by the flowering plants. The jaw muscle patterns simply confirm the
reality of the families as true groups already recognized on other lines
of evidence, so this is hardly a one-factor diagnosis of families. But
in addition these patterns perform the needed function of ranging the
families in a hierarchy from simple (presumably primitive) to complex
(presumably advanced) families. No other traits are likely to do this.
In this hierarchy, the muscle patterns suggest that some of the
groups are of lower level and should be subfamilies. For instance, the
differences in muscle pattern between primitive groups at or close to
the stem stock may be slight. Between the warblers (Sylviinae),
flycatchers (Muscicaplnae), and chats (Saxicolinae) there is little
difference in muscle pattern, so added characters are needed to tell
them apart. The Sylviinae always have the ectethmoid foramen
single, the other two double. Of the other two, the Saxicolinae often
have the outer of the two foramins outside or nearly outside the orbit
and have a much narrower bill. Here muscle pattern combines
related groups into larger families, other characters being necessary to
differentiate the subfamilies. This suffices to show that more than
jaw musculature is used in my phyletic arrangement; there are not
sixty different muscle patterns in the Oscines! But as the more
advanced groups diverge from the stem Sylviidae, greater complexity
of the jaw musculature permits designation of small but constant
facies differences for nearly all families.
My arrangement is not a single-factor diagnosis of families. The
families were already diagnosed by other lines of evidence. The jaw
muscle patterns provide what is so far found nowhere else in the
morphology of the Oscines--a key to relationships of all families.
They are apparently directly due to phylogenetic differentiation as
the families became adapted to new food types.
The Illustrations.--In anatomical work nothing can take the place
of accurate drawings. For those who cannot accept my interpreta-
tions, they represent facts to be reassessed. Several families are
presented in each figure. For each, the small skull vignettes give a
general idea of structure and at the same time outline in black the
muscle area enlarged. Thus the jaw muscle pattern is shown in side
view and in oblique view, looking into the orbit from which the eye
has been removed. The ectethmoid plate is drawn at the top left.
The tongue is drawn at the top right and below it the relief pattern of
the horny palatc below that the bill. Nomenclature follows the
sauropsid terminology of Lakjer (1926), but for easy comparison,
muscle masses are numbered from 1 to 7 with subdivisions a, b, and c.
Figure 2 serves as the key and may be referred to when necessary to
determine the name of a particular muscle; but it is easy to memorize
the position of each muscle by number since there are always just
seven in the Oscines, and the discussion will be restricted to numbers.
FrovR 2. Detail drawing of jaw muscle pattern of an Old World warbler,
showing primitive (parallel) musculature, with characters of ectethmoid plate,
tongue, horny palate, and bill.
Protractors. 1 depresses the lower mandible; 2 elevates the upper mandible.
1. M. depressor mandibulae
2. M. protractor quadrati
Palatine retractors. Combined action draws upper mandible downward.
3. M. pterygoideus dorsalis: a) anterior; b) posterior
4. M. pterygoideus ventralis: a) anterior; b) posterior
5. M. pseudotemporalis profundus
Mandibular adductors. Combined action draws lower mandible upward.
6. M. pseudotemporalis superficialis
7. M. adductor mandibulae: a) externus superficialis; b) externus mediaIls; c) ex-
ternus profundus; d) posterior
The origins and insertions of muscles and their specific functions in
the kinetic bird skull are well-described in Moller (1931) and Fiedler
(1951). The brief discussion in Beether (1951a) may be enough for
general needs, and figure 2 in that paper, showing mass functions of
muscles, should help in visualizing functional emphasis in various
groups.
The family diagnoses of Sharpe (1874-1898), Ridgway (1901-1907),
and others were really detailed accounts of the range of variation in the
group and often failed to eliminate species which they did not intend
to include. To save space some features of the familiar key are
adopted here. Superfamily and assemblage characters are not re-
peated under group diagnoses, which are very brief, so that the figures
themselves must take the place of lengthy description. To show
relationships, similarities are often emphasized, but each group has a
combination of characters that sets it apart from other groups.
iDIAGNOSES AND iPHYLOGEN3/4 OF THE OSCININE HIGHER GROUPS
If we erect a phylogeny on the basis of jaw muscle patterns and other
internal and external characters, the logical procedure is to work
outward from the simple and primitive to the complex and advanced.
We thus arrive at a typical tree with the weak-billed insect-eaters at
the base giving rise to stronger-billed shrike-flycatchers and shrikes,
or to nectar-, fruit-, and seed-adapted or omnivorous groups as the
terminal twigs (figure 18). We find that these terminal groups are in
every way more complex, with increased pinnate musculature, stronger
bills, more intricate palate relief, a tendency toward double ectethmoid
foramina, and generally more complex plumage, habits, and behavior.
But it follows that these differences decrease as we come lower down
in the tree and, where a number of groups leave the stem Sylviidae,
their relationships are often not so clear. Whether they come from
each other, from the Sylviidae or from a common ancestor may never
be known. Where such cases arise I have tried to present the problem
and give reasons for my own decision.
A major phylogenetic division of oscinine families into the super-
families Sylvioidea and Timalioidea appears possible, largely on the
basis of the parallel or pinnate character of adductor slip M7b (figure 2).
Though small, this difference holds remarkably well for these two
large groups, and one is tempted to conjecture that inability to evolve
a pinnate M7b prevented Sylvioidea from producing shrike or finch
adaptations so typical of the more numerous Timalioidea in which it
is pinnate. Theoretically, the simpler Sylvioidea, embracing the stem
Sylviidae (figure 18), evolved the Timalioidea with its complex M7b
via such a group as the Cisticolinae, then may have been unable to go
further in this direction against the competition of that group. How-
ever, it did apparently evolve several family assemblages with a
parallel M7b: the crows, cuckoo-shrikes, and bulbuls; the flycatchers,
thrushes, swallows, and starlings; the Old World nectar-feeders,
exclusive of the Meliphagidae.
This major division is most open to question at the very stem where
the grass and bush warblers (Cisticolinae) are split off from the sylviine
warblers (Sylviinae) as the basic stock of the Timalioidea. Here
further study may reveal a gradient between the two warbler groups
rather than a sharp break. But in drawing a phylogenetic tree it
would still be necessary to recognize the extremes of the gradient as
having different evolutionary potentials due to parallel or pinnate
M7b. The timalioid flycatchers (Monarchidac), however, seem to be
separated from the sylvioid flycatchers (Muscicapinae) by an absolute
dichotomy of four characters. The former has M7b pinnate, ecteth-
moid winged, foramen single, young unspotted; the latter has M7b
parallel, ectethmoid truncate, foramen double, young spotted. They
may prove homogeneous, but present evidence suggests partial paral-
lelism in ecological niche (and hence in plumage) following slight
initial divergence. With this preamble we now take up the higher
groups and, since it would be impossible to express their relationships
in any linear sequence (figure 18), each line is pursued to its evolu-
tionary termination from supposed beginnings in the stem Sylviidae.
THE SUPERFAMILY SYLVIOIDEA
This is the smaller of the two superfamilies making up the suborder
Oscines and may have been restricted in its adaptive radiation through
competition with the more efficient Timalioidea.
OLD WORLD INSECT-EATERS (SYLvImAE).--The several subfamilies
listed are regarded as having evolved to fit different food-niches:
warblers (Sylviinae), bulbuls (Pycnonotinae), flycatchers (Muscica-
pinae), and grass warblers (Cisticolinae). All have the ectethmoid
truncate, its foramen single (except Muscicapinae), and the lacrymal
fused (figure i).
WXRBLERS (S3/4vIINXr).--Diagnosis: Muscle pattern (figure 2) simple, parallel;
M6 bifid. Bill notched, weak, narrow, with operculate nostril and rictal (and often
nasal) bristles. Palate relief simple with lateral and central ridges disappearing
posteriorly, the latter separated by a slight vault from a posterior ridge encircling
the choanal field. Tongue slender with extensive reedy tip. (By "reedy" I mean
blade-like. The passerine tongue usually ends in an extension of the ventral kera-
tinized sheath, resembling the reed of a clarinet.) Ten-primaried, world-wide insect-
eaters with mainly plain plumage, unspotted young. Species dissected: Abroscopus
schistaceps, A crocephalus arundinaceus, Calamocichla newtoni, Calamonastes cinereus,
Camaroptera griseiventris, Camaroptera sp., Chlorotesia sp., Cryptolopha sp., Conopo-
deras familiaris, Dromaecercus seebohmi, Ephthianura tricolor, Erythrocercus mccalli,
Macrosphenus concolor, Oligura superciiaris, Orthotomus sutorius, Phylloscopus
borealis, Polioptila dumicola, P. plumbea, Ramphocaenus rufiventris, Seicercus polio-
genys, Seicercus sp. Discussion: The diagnostic characters, including the single
foramen, are considered primitive, and this world-wide group fulfills the requirements
of an ancestral oscinine stock. The similarity of the long-billed Orthotomus, Macro-
sphenus, and Ramphocaenus poses a problem (Rand and Traylor, 1953), but I regard
them as independent, endemic derivatives of generalized sylviid stock in the Oriental,
Ethiopian, and Neotropical regions respectively--not closely related species. Func-
tion: These three genera differ from generalized warblers in greater expansion of the
protractors M1 and M2 for prying in the manner of starlings and American icterids
[ Auk
280 Bcm, Phylogeny of Oscines tVol. 7o
Fou 3. Characters in the flycatchers and thrushes.
(Beether, 1950; 1951a). This is further evident in the dorso-ventral strengthening
of the laterally compressed bill, especially in Macrosphenus which pries in dead
branches for insects (Bannerman, 1936: 127).
FLYCATCHER, THRUSH, STARLING, SWALLOW ASSEMBLAOE.--Arising
from Musclespinae (figure 18), these groups show strong affinities in
plumage and internal structures, but diverge in feeding adaptations.
All have the ectethmoid truncate (except Sturnidae), foramen double,
and lacrymal fused.
FLVC,TCaRS (Mvscxc,?x,).mDiagnosis: Muscle pattern (figure 3) similar to
that of the Sylviinae but aponeurosis of M7b very narrow. Bill notched, broad, flat,
with non-operculate nostril and abundant rictal and nasal bristles. Palate as in
Sylviinae but no vault, the posterior ridge crowding the central one anteriorly.
Ectethmoid truncate. Broad tongue tapering to short, bifid, reedy tip. Ten-
primatied Old World flycatchers with plain or streaked plumage and spotted young.
Species dissected: A ntkipes moniliger, A rizdomyia latirostris, A rtomyias sp., Culicicapa
ceylonensis, Melaenorni sp., M. pammelaina, Muscicapa latirostris, M. murinus, M.
parrs, M. rubeculoides, M. sundata, M. tkalassina, M. tickelliae, Stizorkina frazeri.
Following Delacour (1947) I have synonymized 7 genera under Muscicapa. Discus-
sion: Double ectethmoid foramen, spotted young, and flycatching may be advances
over Sylviinac. A rtomyias, with flycatcher behavior and musculature but wing,
skull, and bill approaching the swallows, suggests how this group could have evolved
the Hirundinidac.
THRUSHES (TuRrnr)AE).--The included subfamilies, linked by sev-
eral fines of evidence, appear to be diverging under selection by slightly
different food-niches: chats (Saxicolinae), thrushes (Turdinae),
mimic thrushes (Miminae), and dippers (Cinclinae).
Cxe,Ts (S,xcoI,xN).--Diagnosis: Muscle pattern (figure 3) similar to that of the
Muscicapinae but generally weaker adductors M7a and stronger palatal retractors
M4a. Protractors M1 and MZ reduced. Unlike Muscicapinae, the outer ecteth-
mold foramen (figure 1) is often outside or nearly outside the orbit. Bill notched,
narrower than in Muscicapinae, non-operculate (except Prundla), rictal bristles
virtually lacking. Palate similar to that of the Sylviinae but posterior ridge less
prominent. Tongue also similar to that of the Sylviinae. Ten-primaried flycatchers,
mostly terrestrial, and Old World, with usually plain (some streaked) patterns
and spotted young. Species dissected: Brachypteryx leucophrys, Cercomela familiaris,
Cickladusa sp., Copsyckus saularis, Enicurus maculatus, Eritkacus rubecula, Erythro-
pygla barbara, Ixoreus naevius, Kittacincla malabarica, K. tricolor, Luscinia calliope,
L. cyanea, L. sibilans, L. svecica, Myiadestes genibarbis, Myiomela leucura, Myrmeco-
cickla arnauti, Oenantke oenanthe, Oxylabes madagascariensis, Pkoenicurus ockruros,
P. pkoenicurus, Pratincola sp., Prunella modularis, Saxicoloides fulicata, Sialia sialis,
Tkamnornis chloropetoides, Zeledonia CotGnats. Discussion: Oxylabes and Tkamnornis
have often been put in the Timaliidae or Sylviidae, but the double ectethmoid
foramen and complex M3b (never found in those groups) place them here. Prunella
has very strong palatal ridges; its trifid M6 and the trifid pinnate M6 of Zeledonia
are unique in this family. Both should be given at least the status of tribes, the
Prunellini apparently being nearest Phoenicurus. Function: The chats seem to
stem directly from the Muscicapinae on the basis of plumage (especially spotted
young) and internal characters. In Muscicapa (Muscicapinae) fibers split off M3b,
to form a distinct M. retractor palatini, inserting on the basitemporal; this "complex"
M3b, retracting the palate and drawing the upper mandible down powerfully, is
elaborated in the chats Oxylabes, Thamnornis, Saxicoloides, Oenanthe, Erithacus,
Phoenicurus, Myiadestes, and Sialia. In Cichladusa and nicurus (the aquatic
forktail), M3a is advanced anteriorly along the palatine clasp as in the dipper,
Cindus, and this added retracting power may be related to holding slippery prey.
Revision by Ripley (1952).
THRUSHES (TtmmA).--Diagnosis: Muscle pattern (figure 3) similar to that of
the Saxicolinae but more massive, with complex M3b and pinnate temporal slip of
M7a. Bill notched, stronger, non-operculate, with rictal bristles. Palate similar
but with papillae anterior to choanae. Tongue as in Saxicolinae. World-wide, ten-
primaried ground-feeders. Species dissected: Hylocichla guttata, H. ustulata, Mimocich-
la sp., M. rubripes, Myiophonus temminckii, Oreocincla lunulata, Turdus falcklandii,
T. migratorius, Zoothera sp. Discussion: The thrushes seem to be more terrestrial
than chats. Function: The dorso-ventral strengthening of the laterally compressed
bill, especially in Myiophonus and Zoothera, with the massive retractor M3b, may be
an adaptation for grasping slippery prey, and the evolution of some forms may be as-
sociated with a diet of earthworms. Revision by Ripley (op. cit.).
Mmc THRUSHES (MmztE).--Diagnosis: Muscle pattern (figure 3) similar to
that of the Turdinae but M7a smaller, M6 and M1 larger. Bill, palate, and tongue
similar, but bill usually decurved (bill of Toxostoma is un-notched, palate flat).
Ten-primaried New World ground-feeders with plain, streaked, or spotted plumage.
Species dissected: Cinclocerthia ruficauda, Donacobius atricapillus, Dumetella carolinen-
sis, Margarops fuscatus, Melanoptila glabrirostris, Melanotis caerulescens, Miraodes
graysoni, Mimus gundlachii, M. polyglottos, Nesomimus trifasciatus, Oreoscoptes mon-
tanus, Toxostoma curvirostre, T. longirostre, T. rufum. Discussion: The double
ectethmoid foramen and the muscle differences suggest that the supposed affinity of
the Miminae to the babblers or wrens is the result of convergence. The Miminae
may stem from the Turdinae, via Margarops for instance, thrashers being a specialized
end product. Function: The palate-retracting musculature of ancestral thrushes
might preadapt thrashers for pick-ax digging (Engels, 1940) by bracing the more
solid, bony mandibles against resistant eaxth.
DrrERs (CcLAE).--Diagnosis: Muscle pattern (figure 4) similar to that of
the Turdinae but M3a advanced anteriorly on the palatine clasp. Protractors M1
and M2 expanded. Bill narrow, notched, dorso-ventrally strengthened, upturned,
operculate, without rictal bristles. Palate and tongue similar to those of the Tur-
dinae but narrower. Ten-primaried world-wide, montane, stream-bottom feeders.
Species dissected: Cinclus mexicanus. Discussion: This group may have arisen from
the Saxicolinae. The forktails (see Microcichla) show most of the adaptations of
dippers, even the advanced M3a and aquatic feeding; but they retain rictal bristles
and lack the dense plumage. Function: The expansion of protractors M1 and M2
and dorso-ventral strengthening of the upturned bill suggests some prying under the
rocks of stream beds in both groups.
SwA,x, ows (Hmvi)iiI),).--Diagnosis: Muscle pattern (figure 4)
similar to that of the Muscicapinae but adductors M6 and M7 weaker,
protractors M1 and M2 expanded. Bill notched, very broad and
flat with operculate nostril and vestigial rictal bristles. Palate
broad, with weak relief; tongue broad, tapering to a short, bifid, reedy
DIPPER'" q.x.\xx .ixu ~ CINCLINAE'
FIGURE 4. Characters in dippers, starlings, swallows, and silky flycatchers.
tip. Nine-primaried (tenth vestigial), world-wide aerial insect-eaters
with plain or streaked (often iridescent) plumage and more or less
spotted young. Species dissected: Hirundo aethiopica, H. tahitica,
Iridoprocne albiventris, Lamprochelidon sclateri, Petrochelidon fulva,
Progne subis, Psalidoprocne fuliginosa, Pseudochelidon eurystomina,
Pygochelidon cyanoleuca, Tachycineta thalassina. Discussion: I agree
with Lowe (1938) that Pseudochelidon is an aberrant swallow, the
bronchial half-rings (instead of full rings) suggesting relationship with
such a flycatcher as Artomyias. It has no connection with the
Artaminae or Prionopinae. Function: The expansion of protractors
M1 and M2 will permit wider opening of the mouth, especially
by lifting the upper mandible. The forward-directed, black, loral
feathers of swallows, starlings, and some flycatchers are under muscu-
lar control (Lorenz, 1949) and constitute a functional lens-shade
associated with forward vision. In the same connection the ecteth-
moid plate of swallows and starlings falls short of the zygoma. The
jaw musculature and associated characters suggest that both stem
from the Muscicapinae along with Turdidae. Both have vestigial
tenth and long ninth primaries like Artomyias as well as partial for-
ward vision with specialized loral feathers. A few muscicapids,
Melaenornis for example, have iridescent black plumage similar to
that in some starlings and martins. Similar plumage patterns are
seen in the following swallow-starling pairs: Iridoprocne-Pholia, Hir-
undo-Cinnyricinclus, Progne-A plonis, Hirundo-Saroglossa. Streaked
plumage occurs in some swallows and flycatchers (Muscicapa, Arto-
myias) and, as a rule, in juvenal starlings.
STARLinGS (SrmmA).--Diagnosis: Muscle pattern (figure 4)
similar to that of the Turdinae in complex M3b and to that of the
Hirundinidae in small M6 and large protractors M1 and MZ. Bill
varies from the un-notched wedge of Sturnus to the stout, notched,
and arched beak of Gracula; nostril usually non-operculate; without
rictal bristles. Palate generally vaulted and resembling that of the
Turdinae, but flat in Sturnus. Ectethmoid winged. Tongue with
bifid tip. Ten-primaried (short tenth and very long ninth) Old
World fruit- and insect-eaters. Species dissected: A cridotheres tristis,
Aplonis grandis, A. metallicus, A. minor, Cinnyricinclus leucogaster,
Gracula religiosa, Mino dumontii, Scissirostrum dubium, Sturnus
contra, S. roseus, S. vulgaris. Discussion: See Hirundinidae above.
Function: Starlings, especially ground-feeders, have the protractors
M1 and M2 extremely large in association with prying. Sturnus
repeatedly parts the grass mat or probes by spreading the mandibles,
at the same time directing the eyes between them. Birds with marked
FoumE 5.
Characters in bulbuls, orioles, and crows.
forward vision of this sort have a temporal as well as the usual central
fovea. The complex M3b may be for the same purpose noted in the
Turdidae. Revision by Amadon (1943).
BULBULS, CORVINE BIRDS, WAXWINGS. CUCKOO-SHRIKES, AND
NECTAR-FEEDERS.--All of these groups (families below) appear
traceable to the bulbuls, here regarded as a specialized branch (Pyc-
nonotinae) of the Sylviidae. All-have M7b very short, its insertion on
the inside surface of the mandible far posterior to that of M7a on the
outside surface. Ectethmoid truncate. Single foramen becoming
double in all terminal groups.
BI/LBI/LS (P3/4cOOTIA).--Diagnosis: Muscle pattern (figure 5) similar to that
of the Sylviinae (especially Macrosphenus), the fibers of M7a (temporal slip) converg-
ing in an aponeurosis and M7b short (ventral slip of M7c not seen in figure). Outer
slip of M6 longer than the inner with a large gap between the latter and M2. Fora-
men single or pinched (double in Andropadus). Bill notched, slender to stout,
generally decurved, operculate, with rictal bristles. Tongue generalized, but
tendency for the horny papillae to be double-ranked. Palate as in the Sylviinae but
posterior ridge reduced. Ten-primaried Old World (not Australian) fruit- and
insect-eaters, usually with inconspicuous warbler-like plumage. Species dissected:
Criniger tephrogenys, Iole olivacea, Microscelis macdellandi, M. tickelli, M. virescens,
Phyllastrephus strepitans, P. terrestris, Pycnonotus barbatus, P. cafer, P. dispar, P.
finlaysoni. Discussion: The characters distinguishing this subfamily from Sylviinae
seem to link it to various derived groups below. Function: The more massive muscu-
lature agrees with a stronger bill while the expansion of M1 and M2 suggests added
prying ability. Delacour's (1943a) "family" characters are weak; his assertion that
the neck is short is not supported by skeletal material.
FAIRY BLUEBIRD, CHLOROPSIS (ImNlNI).--Diagnosis: Muscle pattern (figure 5)
pycnotine but M3a advanced, bifid M6 (trifid in Chloropsis); M1 and M2 emphasized.
Ectethmoid foramen double.' Tongue, bill, and palate pycnonotine, but Chloropsis
with nectar adaptations (see below). Species dissected: Chloropsis cochinchinensis,
Irena puella. Discussion: Many features of derived groups are forecast in this tribe
of the Pycnonotinae, which does not include A egithina or A ethorhynchus; the forward
advance of M3a on the palatine dasp, trifid M6, reduction of rictal bristles, increased
pinnate character of the muscles, expanded protractors, and the curled, whipped-out,
nectar-adapted tongue (Chloropsis). Function: Vacuum is apparently created in
this sucking tongue by catching its tubular part between the opposing ridges of
upper and lower mandibles (A-A') while the palatal boss engages the notch of the
tongue (B-B'). In this position the brushy tip protrudes beyond the bill tip.
THE CORVINE ASSEMm,AoE.--This group, comprising the Ptilono-
rhynchidae, Callaeidae, Paradisaeidae, and Corvidae, is typified by
double ectethmoid foramen, free lacrymal, advanced M3a, short M7b,
tendency to pinnate adductors, loss of rictal bristles, and plumage
specialization. The Oriolidae, a primitive group dose to the Corvidae,
has M3a not advanced as in jays.
BOWER BIRDS (PTILOORH3/4NCHID.E).--Diagnosis: Muscle pattern
(figure 6) similar to that of the Pycnonotinae but adductors M7a and
BIRD O1 PARADIS ~?,ra a ~ PARADI $AF=IDAF::
BOWxR BIRD ~ l\xxt \'.\'~PTILONORHYNCI-IIDAI
CUCK00' SHRIKE- ~?e6.c,3/4us %,,,,'"CAMPSPI4AGIDAI5
Fmum 6. Characters in cuckoo-shrikes and Australian crow-like birds.
M7c pinnate, M3a advanced. Bill notched, arched, stout to slender;
nostril operculate or feathered; without rictal bristles. Tongue with
radiating surface-papillae and quadrifid, reedy tip. Palate (Aeluroe-
dus) with posterior ridge joined to anterior or (Prionodura) with
posterior ridge greatly reduced as in Pycnonotus layardi. Ten-
primafled corvid-like fruit- and insect-eaters of the Australian region.
Species dissected: Aeluroedus crassirostris. Discussion: Affinity to the
Pycnonotinae is seen in the gap between M2 and M6 and in the
characters of the coryinc assemblage, even in the specialized Aeluroe-
dus, but on the basis of external characters, the bulbuls are disjunct
from their presumed descendant groups (of. Delacour, 1943). The
papillate tongue of A eluroedus is approached by Pycnonotus finlaysoni,
and partial resemblance in plumage is seen in bulbul-bowerbird pairs
like Trachycomus-Sericulus, Chloropsis-Xanthomelas. Some members
of both groups are mimics. But the Pycnonotinae do not reach the
Australian region, and we are obliged to assume that the ancestral
bulbul-like stock which reached there evolved into the endemic
families treated here and below. Function: Adduction and palate
retraction as throughout assemblage.
BIRDS OF PARADISE (PARADISAEIDAE).--Diagnosis: Muscle pattern
(figure 6) similar to that of the Ptilonorhynchidae but M6 trifid pin-
nate, M7b reduced, and M1 and M2 expanded. Bill notched (except
in riflebirds), without rictal bristles; nostril operculate or feathered.
Palate with long central ridge fused to posterior ridge. Tongue
surface papillate with double-ranked horny papillae posteriorly.
Lacrymal free in Ptilorhis, fused in Paradisea. Species dissected:
Paradisea rubra, Ptilorhis paradisea. Discussion: If this actually is
another corvid-like endemic group which evolved in the Australian
region from ancestral pycnonotine stock, the tendency toward bare
nape in bulbuls may be associated with often naked nape in the Par-
adisaeidae; the long nape "hairs" of the bulbul Tricholestes may be the
"anlagen" of feather specialization, the red-throated mutant of
Pycnonotus dispar johnstoni (de Schauensee, 1946: 53) the forerunner
of the bright coloration in descendant groups.
WATTLE BIRDS (CALLAEIDAE).--Dia;gnosis: Muscle pattern (figure
6) nearest that of Aeluroedus but M6 trifid, temporal slip of M7a re-
duced; M7c, M4a, and M1 expanded. Bill un-notched, varying from
the straight wedge of Philesturnus to the arched beak of Callaeas,
operculate, without rictal bristles. Palate with lateral bosses papillate
like the tongue of Aeluroedus. Tongue truncate with quadflfid tip
and raised mid-rib suggested in A eluroedus. Endemic New Zealand
leaf- and insect-eaters. Species dissected: Callaeas cinerea, Philestur-
nus carunculatus. Discussion: A primitive corvid-like group most
closely allied to bower birds (plumage pattern of Callaeas resembles
that of the related cuckoo-shrikes). Function: the palate in Callaeas
(raised as in Pkytotoma) is adapted for leaf-eating. Philesturnus is
convergent with Sturnus in having enlarged protractors M1 and MZ,
otherwise like Callaeas.
OLD WORLD ORIOLES (ORIOLIDAE).--Diagnosis: Muscle pattern
(figure 5) similar to that of the Pycnonotinae, but M6 trifid and pin-
nate. Bill notched, of moderate strength, operculate, with rictal
bristles. Tongue unspecialized. Palate with central ridge more or
less confluent with weak posterior ridge. Ten-primaried Old World
fruit- and insect-eaters. Species dissected: Oriolus chinensis, O. xan-
thornus. Discussion: Similar in plumage to some of the Pycnonotinae;
in some ways, this unspecialized, anatomically primitive group also
parallels the jays.
CROWS, JAYS, MAGPIES (CoRvIDAE).--Diagnosis: Muscle pattern
(figure 5) similar to that of the Oriolidae, but M7a and M7c pinnate
and outer slip of M6 advancing its insertion on the mandible (in
Corvus M3a likewise is advanced). Bill seldom distinctly notched;
rictal bristles present; nostril feathered. Tongue with horny papillae
double-ranked. Palate usually with posterior ridge suppressed, but
fused with central ridge in Cissa. Ten-primaried world-wide omni-
vores. Species dissected: Aphelocoma ultramarina, Cissa chinensis,
Cissilopha melanocyanea, Corvus brachyrhynchos, Crypsirhina temia,
Cyanocitta cristata. Discussion: The partly pinnate adductors of the
Oriolidae are intermediate between the pinnate adductor muscula-
ture of the Coryidac and the mainly parallel musculature of the Pyc-
nonotinae. The variable black and white plumage of the bulbul
Microscells madagascariensis suggests that of the Coryidac; anatomi-
cally, the bower birds are intermediate between bulbuls and crows.
Function: In most of these omnivores, hammering plays a role in food-
getting. Revision by Amadon (1944).
THE CUCKOO-SHRIKE, WAXWING ASSEaBLAGE.--The families of
this assemblage seem to have arisen from the Pycnonotinae mainly
with plumage and diet specialization and with the internal specializa-
tion of free lacrymals. Ectethmoid truncate. Foramen variable, but
double in most advanced forms.
CUCKOO-SHRIKES (C.aa'E,HAGIDAE).--Diagnosis: Muscle pattern
(figure 6) as in the Pycnonotinae, but the insertion of M3a advanced
and the gap lacking between MZ and M6. Bill notched; rictal
bristles present; nostril feathered. Palate vaulted with central
ridge disappearing posteriorly (crow-like). Tongue with papillae
double-ranked ventrally and "quadrifid" tip (bifid with lateral
fringes). Ten-primaried Old World fruit- and insect-eaters. Species
dissected: Coracina lineata, C. melanops, C. papuensis, Edolisoma holo-
pollurn, Edolisoma sp., Lalage maculosa, L. niger, Malindangia sp.
Discussion: Delacour places Tephrodornis and Hemipus here, but the
former agrees on every point with the Prionopinae, extending the
range of this group into the Oriental region; the latter is a monarch
flycatcher. Function: The advanced MSa increases the strength of
palatal retraction in this group as in the assemblage.
WAXWINGS, SILKY FLYCATCHERS, PALM CHATS (BoMBYCILLIDAE).--
Diagnosis: Muscle pattern (figure 4) similar to that of the Campe-
phagidae but M7c pinnate and extended dorsally with gap between
M2 and M6 as in the Pycnonotinae. Bill notched, short and broad,
non-operculate, with rictal bristles. Tongue as in the Campephagidae
(Phainopepla with papillate surface like Pycnonotus finlaysoni and
A eluroedus). Palate of Phainopepla like that of the Campephagidae;
palate of Bombycilla like that of the Pycnonotinae. Ten-primaried,
fruit- and insect-eaters, mainly of the New World. Species dissected:
Bombycilla cedrorum, B. garrula, Dulus dominicus, Phainopepla nitens,
Phainoptila melanoxantha, Ptilogonys cinereus, Hypocolius ampelinus.
Discussion: Despite the close similarity of Campephagidae and Bomby-
tillidac, they are thought to have arisen from the Pycnonotinae
independently by specialization of characters incipient in that group.
Both groups have the lacrymal free, similar internal characters
throughout, and plumage specialization with crests. An examination
of Col. Meinertzhagen's specimen of Hypocolius clearly establishes its
position in the Bombycillidae, and the fused lacrymal may indicate
that it is a little closer to typical bulbuls than the other bombycillids.
See Delacour and Amadon (1949).
THe; OLD WORLD NECTAR-FEEDER ASSEMBLAGE.--The sunbirds,
flower-peckers, and white-eyes share many internal characters with
the Pycnonotinae, lacking only the gap between M6 and MZ charac-
teristic of the Pycnonotinae. They could have arisen from the
Sylviinae dose to the bulbul stem; but the serrate-tipped mandibles of
sunbirds and flower-peckers may be forecast in such a bulbul as
Andropadus, and it is relatively easy to derive the plumage types of
the whole assemblage from bulbuls. All have the ninth primary long
and the tenth short, the ectethmoid truncate, lacrymal fused, and a
'large palatine salivary gland.
WHITE-EYES (ZOSTEROPIDAE).--Diagnosis: Muscle pattern (figure
7) similar to that of the Pycnonotinae, but protractors M1 and MZ
expanded, M6 suppressed, M4b split to accommodate a palatine sali-
gR-PCKR- 3ica m DICAID
MITS-SY5 s q ZOSTOPID
Fxo 7. Characters in sylvioid nectar-feeders.
vary gland visible in the floor of the orbit. Ectethmoid foramen single.
Bill slender, essentially un-notched, operculate, with rictal bhsfles.
Palate similar to that of a sylviid or bulbul; tongue unspecialized, but
that of Zosterops virens whipped out into quadrifid tip and tubular.
Nine-primaried (tenth yesrigid) insect- and nectar-feeders of the
Old World. Species dissected: Zosterops japonica, Z. teralis, Z. palpe-
brosa, Z. virens. Discussion: Regarding the pycnonotine origin, the
bulbul Phyllastrephus osterops resembles white-eyes in plumage.
Function: Anatomically, white-eyes are nothing but warblers (or
bulbuls) adapted for nectar-feeding by the expanded M1 and Mr, the
loss of the bill-notch and rictal bristles, and the sometimes specialized
tone, which functions as described for the Irenini.
SUSmRDS (NcrARxsxm.).--Diagnosis: Muscle pattern (figure 7)
irailar to that of the Pycnonotinae, but protractors M1 and M2
expanded and inner slip of M6 longer. Ectethmoid foramen double.
Bill un-notched, slender, usually long, and decurved, serrate at tip,
operculate, without rictal bristles. Palate with central ridge set in a
groove and a raised boss far posterior. Tongue flat posteriorly with
twin tubes separate anteriorly but fusing in the mid-portion. Ten-
primaried (tenth short) nectar-feeders mainly of the Old World
tropics. Species dissected: Aethopyga gangliae, ,4. nipalensis, ,4.
siparaja, ,4nthreptes collaris, ,4. malaccensis, Chalcoparia singalensis,
Cinnyris jugularis, C. olivacea, C. oseus, C. reichenowi. Discussion:
The small size of sunbirds does not preclude derivation from larger
bulbul-like ancestors, for size is adaptive; on the other hand the nest
of the primitive sunbird ,4rachnothera suggests relationship to the
warbler Orthotomus which has a "pinched" foramen intermediate
between the single foramen of warblers and the double foramen of
sunbirds. But the double foramen in sunbirds is matched in many
groups diverging from the stem warblers. On such fine points of
derivation we cannot be sure, and figure 18 expresses my best guess.
Function: The expansion of protractors M1 and M2 indicates their use
in prying into neetaries of flowers. The tongue functions as described
for the Irenini, but the dorsal fusion of the twin tubes makes it more
efficient. See revision by Delacour (1944) for tongue variants in
,4 rachnothera and ,4 ethopyga.
FxowR-PcrRs (DxcamA).--Diagnosis: Muscle pattern (figure
7) similar to that of sunbirds, but temporal slip of adductor M7a ex-
panded and M3a advanced--protractors M1 and M2 reduced. Ec-
tethmoid foramen double. Bill un-notched with finely serrate tip
(notched in Pardalotus), operculate, without rictal bristles. Palate
with central and posterior ridges fused. Tongue similar to that of
sunbirds, but twin tubes each bifid terminally and not fused medially.
Nine-primaried (tenth vestigial) fruit- and insect-eaters of the Aus-
tralian and Oriental regions. Species dissected: Dicaeum aeneum, D.
concolor, D. cruentatum, Melanocharis versteri. Discussion: The sun-
birds and flower-peckers seem to have diverged from a common stock,
the former as nectar-feeders with increased protraction, the latter as
berry-eaters (mistletoe), with stronger adduction, but with above-
average protraction for secondary nectar-feeding. Function: The
tongue functions as in the Irenini, but the central palatal ridge has a
sharp elevation (C), and the pattern of the tip of the upper mandible
(D) is matched by that of the lower (D'). The serrate bill-tip,
probably adapted for fruit-grasping, may be forecast in the multiple
CRUB WiqfN ~ % v'xcxixx&s ~ MURINI
FIGU 8. Characters in babblers d timioid warbles.
bill-notches of the bulbul Andropadus. Revision by Mayr and
Amadon (1947).
THE SUPERFAMILY TIMALIOIDEA
The Timalioidea form the larger of the two major divisions of the
Oscines (figure 18). In the basic stock of this group, the capacity to
evolve a pinnate M7b has permitted the development of shrike- and
finch-like groups; the lack of this capacity apparently prevented the
Sylvioidea from evolving similarly adapted forms. Two plumage
types dominate this supeamily. One is a pattern of shaft-streaks,
particulady on head and back. The other is a bold recognition pat-
tern consisting of a black breast-crescent, auHculars, and crown, set
off by light throat, forehead, and malar and superciliary regions.
This is evident in virtually all timalioid families, though often present
only in part and sometimes apparently obliterated by extensive
black or white. It is also found outside the Oscines, but within the
suborder it is almost confined to the Timalioidea, only wheatears and
jays among $ylvioidea showing it.
To trace timalioid origins, it is now necessary to return to the stem
$ylviidae where warblers of the subfamily Cisticolinae exhibit pinnate
M7b in its most primitive expression.
GRASS AND BUSH WARBLERS (CISTICOLINAE).--Diagnosis: Muscle
pattern, etc. (figure 8) similar to that of the Sylviinae but M7b pinnate.
Bill slender, notched, operculate, with rictal bristles. Ectethmoid
winged, lacrymal fused. Tongue and palate similar to those of the
Sylviinae but lateral ridges crowding center ridge posteriorly. Ten-
primaried Old World insect-eaters. Species dissected: Bradypterus
castaneus, Cisticola galactotes, Cisticola sp., Horeites canturiens, Horornis
montana, Locustella ochotensis, Megalurulus mariei, Megalurus palus-
iris, Pnoepyga pusilla, Prinia atrogularis, Schoenicola brevirostris.
Discussion: This subfamily of the stem Sylviidae seems to be a key
group from which the timalioid families all arise. The dark breast
crescent of Prinia fiavicans may foreshadow the recognition pattern
mentioned above; Cisticola typifies the shaft-streak pattern. Re-
visions in part by Lynes (1930) and Delacour (1942-1943).
GRASS Am) BJs}I WARBleRS (MJRN).--Diagnosis: Muscle pattern (figure 8)
like that of the Cisticolinae but M4b tending to split into two slips. Ectethmoid
plate truncate and falling short of zygoma as in true wrens. Tongue and bill similar
to those of the Cisticolinae but nostril more broadly operculate. Palate with lateral
ridges dippearing posteriorly. Ten-primaried Australian region insect-eaters,
some with plumage specialization. Species dissected: Amaurodryas vittata, Calaman-
thus fuliginosus, Gerygone magnirostris, Gerygone sp., Lamprolia victoriae, Malurus
cyanea, Petroica multicolor, Petroica sp., Sericornis humilis, Stipiturus malacurus,
Todopsis sp., Vitia ruficapilla. Discussion: The colorful Lamprolla is definitely not
related to the birds of paradise. The outer slip of M6 is longer than the inner slip in
Vitia and Lamprolla of Fiji; this suggests the origin of the latter from the former.
Todopsis has the tip of the bill broadened.
MONARCHS, WHISTLERS, DRoNGOS, AND VIREOS (MONARCHIDAE).--
Internal characters are the basis for uniting these rather distinct
shrike-flycatcher groups in a new family, the Monarchidac. All have,
in common with Cisticolinae, a winged ectethmoid, a large, single
foramen, fused lacrymal, and a prominent post-orbital process, but in
their specialized bills show an advance over that group.
MORc}I FL3/4CTC}IRS (Mo.cI.).--Diagnosis: Muscle pattern (figure 9)
similar to that of the Cisticolinae (but M6 becoming trifid and pinnate in Terpsi-
phone). M4a with narrow anterior insertion on the slender transpalatine process.
Xr I-I I STLER ~ 3/4acXckxa\a s\u xecez ~ PACHYCPI4ALINAF=
FIcoa 9. Characters in shrike-flycatchers.
Bill notched, broad and flat, semi-operculate to operculate, with nasal and rictal
bristles. Posterior palatal ridge separated from anterior ridge only by the paired
palatal nares. Tongue with prominent horny papillae posteriorly and quadrifid tip.
Ten-primaried Old World shrike-flycatchers with plumage specialization culminating
in the paradise flycatchers. Species dissected: Batis poensis, Chasiernpis gayi,
Diaphorophyia castanea, Hemipus picatus, Hypothymis azurea, Lanioturdus torquatus,
Monarcha castaneiventris, Myiagra ferrocyanea, Piezorhynchus sp., Platysteira cyanea,
Rhipidura albicollis, R. cockerelli, R. leucophrys, Terpsiphone paradisi, T. rufiventris.
Discussion: As in the Malurini, a tendency for M4b to split with fusion of the lateral
slip to M4a is seen in Batis, Lanioturdus, and Platysteira. But the small postorbital
process and truncate ectethmoid with a small foramen in the Malurini, contrasted
with the large process and "winged" ectethmoid with large foramen in the Monarch-
inae, suggest common cisticoline origin rather than direct relationship. These bony
characters also distinguish the narrow-billed monarchs from the Malurini. The
Monarchinae differ from the Muscicapinae also in having unspotted young and in
behaving less like flycatchers and more like arboreal insect-gleaners (Delacour, 1947).
DRONGO$ (DICRURINAI).--Diagn0siS: Muscle pattern (figure 9) similar tO that of
Terpsiphone, but M4a, M4b, and the slips of M7 fused (of. monarchs); the temporal
slip of M7a expanded. Bill notched, non-opercuiate with strong rictal and nasal
bristles. Palatal pattern similar to that of the Monarchinae but more vaulted.
Tongue similar to that of the monarchs but with a tendency for the horny papillae to
be double-ranked. Ten-primaried (mainly black) Old World insect- and nectar-
feeders with notable plumage specialization. Species dissected: Dicrurus aeneus, D.
balicasseus, D. coerulescens, D. hottentottus, D. sumatrana. Discussion: Internal ana-
tomy and plumage leave little doubt that this is a specialized group arising from the
monarch flycatchers. D. balicasseus has a white belly like that of Myiagra cyanoleuca,
and Monarcha alecto closely resembles unspecialized forms of Dicrurus in both black
plumage and characters in the bill. Function: In D. hottentottus, the adaptive loss of
the bill-notch and the nectar-adapted tongue indicate a strong approach to flower-
feeding, though the persistence of rictal bristles suggests that insect-eating is still
paramount. The similar quadrifid tongue-tips in this species and in the Meliphagi-
dae suggest a common origin from the same timalioid stock. Revision by Vaurie
(1949).
WHZSLIRs'(PAcH3/4CIPHALZNAI).--Diagnosis: Muscle pattern (figure 9) as in the
drongos but without fusion. Palate and bill similar to those of drongos, but the
latter always notched. Tongue also similar, but without double-ranking of papillae.
Ten-primaried shrike-flycatchers of the Australian Region. Species dissected:
Colluricincla rectrirostris, Pachycephala pectoralis, P. sulfureiventer, Pitohui ferru-
gineus. Discussion: This appears to be a specialized Austro-malayan line arising
from the monarch flycatchers and generally with a deeper, narrower bill.
VIREOS (VIRlONINAl).--Treated below under the American nine-primaried
assemblage.
THE SHRIKE ASSEMBLAOE.--The world-wide, insectivorous Mon-
archidac may have existed before the origin of flowering plants. The
primitive shrike groups of the several faunal regions, apparently
stemming from it independently and with differential emphasis on its
variations, suggest a Tethyan Upper Cretaceous or Eocene distribu-
tion pattern (see yon Reichenbach, 1909). Anatomically, the Aus-
tralian Cracticidae are close to the Vanginae of Madagascar and the
Prionopinae of Africa and India (all having large postorbital processes),
as well as to the Bornean Bald Shrike (Pityriasis). A separate
and later origin of the Laniidae from the Monarchinae is suggested
by their more advanced muscle pattern (pinnate adductors) and re-
duced postorbital processes. The members of the shrike assemblage,
except the Laniinae, have the ectethmoid winged, free lacrymal, and
a single foramen.
THE WOOD SWALLOWS, BUTCHER BIRDS, BALD SHRIKES, AND MAG-
PIE LARKS (CRACTICIDAE).--These four subfamilies are apparently the
result of adaptive radiation from a single monarchinc stock, mainly in
Australia. The radiation of the Vangidae on Madagascar is a parallel
example. Internal characters and the black-and-white plumage
patterns unite the groups, even though the Artaminae are long-winged
00D SW'ALLOW~imu ~ ARTAIMI1NAE-
FIGURI 10. Characters in Australian shrikes.
fly-catchers, the Cracticinae and Pit. yriasidinae are shrike-like, and
the Grallininae are ground insect-eaters.
WOOD SWALLOWS (ARAMINAE).--Diagnosis: Muscle pattern (figure 10) similar
to that of the Monarchinae, but M6 trifid (not pinnate), ensheathed in an aponeuro-
sis, with special development of the temporal slip of M7a; M4a and M4b tending to
fuse (cf. monarchs, drongos). Other internal characters similar to those of the
Monarchinae but lacrymal free (vestigial?). Tongue and palate also similar, but
bill stronger, nostril approaching the slit-like aperture of the Prionopinae. Ten-
primaried, aerial insect-eaters of the Australian and Oriental regions. Species dis-
sected: Artamus leucorhynchus, A. sordidus. Discussion: (See under Vanginae).
Function: The length of M3b suggests powerful palate retraction, as already evident
in Monarchinae, hence, an unusually good grip at the tips of the mandibles. The
swallow-like wing with short tenth and very long ninth primaries, is adapted for
soaring flight.
BUY1/2ItIR BIRDS (CRACYI1/2INAB).--Diagnosis: Muscle pattern (figure 10) similar to
that of the Artaminae but M6 quadrifid and no fusion of M4a and M4b; free lacry-
mal stronger. Tongue, palate, and bill also resemble those of the Artaminae but bill
has a distinct shrike-like hook. Ten-primaried Australian shrikes with rounded
wings. Species dissected: Cracticus cassicus, Gymnorhina tibicon. Discussion: The
musculature is more massive than that of the Artaminae, reflecting the different
feeding habits which mark these distinct adaptive lines. Function: The bill of the
butcher bird (Cracticus) is adapted for tearing impaled animals; Gymnorhina does not
feed in this manner.
BaLD Saanra (PxTxUUASXDXN).--Diagnosis: Internally similar to the Cracticinae,
these groups probably having a common mouarchine origin. Species dissected:
Pityriasis gymnocephalus.
MAGPII$ LARKS AND MvD-NBsr BVXX,DBRS (Gv,x,X,XNXN).--Diagnosis: Muscle
pattern (figure 10) closer to that of Terpsiphone than to that of the other Cracticidae;
but tongue, palate, and plumage support their inclusion in this family. (See
Amadou, 1950a.) Species dissected: Grallina cyanoleuca, Strutlvidea cinerea. Dis-
cussion: The fused lacrymal may be an adaptation for lateral vision characteristic of
some ground feeders, and the reduction in M3b with a trifid pinnate M6 may be simi-
larly explained.
THg VAoAS AD HaT SHRXCS (VxoxDx).--The radiation of
the vangas (Vanginae) in Madagascar has produced forms adapted for
many niches in addition to the shrike-niche. Although clearly dis-
tinct from the helmet shrikes (Prionopinae) of Africa in jaw muscula-
ture and other internal characters, the Vanginae show unmistakable
relationship with that group; and both may have stemmed indepen-
dently from monarch ancestors.
V.NG.S (VANoxNAI).--Diagnosis: Muscle pattern (figure 11) similar to that of
the Artaminae (of. Pycraft, 1907). Bill notched, with rictal bristles (except in
Falculea); nostril non-operculate, feathered. Palate and tongue similar to those of
the Artaminae and Monarchinae. Ten-primaried insect-eaters, confined to Mada-
gascar. Species dissected: Hypositta corallirostris, Schetba tufa, Tylas eduardi. Dis-
cussion: Tylas eduardi appears to be a vangid; it is anatomically very far from the
orioles or the bulbuls (Mayr and Amadon, 1951). ttypositta differs from typical
vangids only in having the laerymal fused and is not close to Sittidae internally.
Mystacornis crossleyi (dissected) may also be a vangid. As is typical for endemic
Madagascar groups (Rand, 1936), the vangids appear to have radiated into many
food-niches from a common ancestral stock. Function: The species examined have a
long M3b, suggesting strong palatal retraction as in the Artaminae, but Schetba tufa
has a unique feature. In this species, the anterior end of the zygoma has a notch-like
eminence dorsally (A)--buttressed by a similar one posteroventrally (B)--so that,
when the palate is fully retracted and the tip of the mandible depressed in maximum
adduction, this notch will fall in place behind the ethmoidal wing (C). Supposedly,
the bird will thus be able to tear or to maintain a grip indefinitely with decreased
muscular effort.
Hx, Saxrs (I:IONO?XNA).--Diagnosis: Muscle pattern (figure 11) similar
to that of the Vanginae but M4a and M4b not fused, the latter splitting into two slips
in Sigmodus and Tephrodornis, but all three fused in Prionops (of. monarchs, drongos).
SH
VANGA SIqlqIKF~%Xx\= ~ VANGINAE
'I-IE-LME-T SHRIKE; ~ %%s xxxw=kxk ~ PRIONOPlINAF:
Fmum 11. Characters in shrikes.
Tongue and palate similar to those of the Vanginae. Bill notched; rictal bristles
present; slit-like nostril feathered. Ten-primaried African and Oriental insect-
eaters. Species dissected: Prionops poliocephala, Sigmodus rufiventris, Tephrodornis
pondicerianus. Discussion: Tephrodornis agrees with the Prionopinae in having
pinnate M7b, split M4b, no advance in M3a, and free laerymal--none of which ever
occurs in cuckoo-shrikes, where Delacour has placed it. This extension of the
range of this ancient African shrike group to the Oriental Region is not surprising.
The early Tethyan distribution referred to above, which is necessary to explain
shrike relationships, would have given the Prionopinae access to the Oriental Region
(particularly southern India and Ceylon). Similarity of muscle pattern, bill, tongue,
and palate (see figures) link the Prionopinae with the Vanginae and with the Pityria-
sidinae and Cracticidae. Function: In Sigmodus, M3b is even more strongly de-
veloped for powerful palatal retraction than in Schetba. This compensates for the
lack of a notched zygoma as in Schetba. Review by Mayr (1943).
TaE Busa SHmKES AND TRuE Samos (LAmmAE).--The Malaco-
notinae and Laniinae, ranging from the Ethiopian and Oriental regions
into the Holarctic, may have arisen from the Monarchinae as a more
successful shrike family that eliminated the less-advanced earlier
shrikes (above) to a large extent in the Oriental Region. The more
primitive shrikes appear to have survived best in sanctuaries like
Australia and Madagascar.
BUSlt Smulrs (MiLiCONOTXNAE).--Diagnosis: Muscle pattern (figure 11) similar
to that of the Monarchinae, but the trifid M6 and M7a pinnate (temporal slip ex-
panded) without splitting or fusion in M4. Ectethmoid foramen single. Post-
orbital process reduced, compared with the more primitive shrikes. Palate and
tongue similar to those of the Monarchinae but nostril semi-operculate and rictal
bristles reduced. Ten-primaried (mainly forest) shrikes of Africa. Species dissected:
Chaunonotus sabinei, Dryoscopus a.nis, D. gambensis, Laniarius atrofiavus, L.
ferrugineus, Nicator chloris, Tchagra senegala. Discussion: Nicator is atypical with
M6 trifid and parallel and M7a parallel, but it fits best here. It is not related to the
Pycuonotinae (contra Delacour, 1943a) and resembles Malaconotus externally.
TRm SalUS (L.NxxN.).--Diagnosis: Muscle pattern (figure 11) similar to that
of the Malaconotinae but more massive and with different structure in M6. Bill
stouter, with strong hook; nostril non-operculate, feathered; rictal bristles present.
Ectethmoid truncate, foramen double; lacrymal fused or lost. Palate and tongue
similar to those of the bush shrikes but the post-orbital process further reduced.
Ten-primaried shrikes of the Old and New Worlds. Species dissected: Cephalopho-
neus nasutus, Lanius excubitor, L. ludovicianus, L. schach, Urolestes melanoleucus.
Discussion: In all shrikes the lateral slip of M6 tends to be advanced in its insertion
anteriorly on the inner surface of the mandibular ramus, and this is pronounced in
Cephalophoneuz. Function: The loss of the laerymal and resulting shortness of the
ectethmoid, which does not reach the zygoma, may permit better forward vision as in
the Starling (Sturnus).
THE HONEY-EATER, WEAVER AssEMBI,AOE.--Many lines of evidence
suggest that primitive honey-eaters, which had evolved an angulated
commissure (prominent in nectar- and seed-adapted groups) but had
not yet lengthened the bill, were pre-adapted to evolve the weavers.
Aethorhynchus (figure 12) is similar in muscle pattern to Ploceus
(figure 12), and the two groups are similarly primitive in the large size
often attained by the ectethmoid foramen. Palatal patterns are not
far out of agreement, and plumage resemblances between the Aus-
tralian honey-eaters and weavers may be significant. Some honey-
eaters build domed nests, the dominant architectural form of weavers.
There are parallel anatomical relationships between the nectar-
feeders and finches of the nine-primaried American assemblage. In
both of these cases the problem of deriving one specialized group from
another is avoided by assuming that both come from a common
unspecialized ancestor.
Ho3/4-EArRs (MI,IpnAoII)a).--Internal characters and the per-
sistence of timalioid plumage patterns suggest a cisticoline origin for
this timalioid family, though it is convergent with the Old World
sylvioid group of nectar-feeders that may have displaced it from much
of its former range. IIylia and Pholidornis, variously Placed in the
Ploceidae and Sylviidae, are unspecialized Meliphagids, wide-ranging
in forested Africa. They may be combined with the specialized
Promerops of the Cape region in the subfamily Promeropinae. This
group is linked with the typical Australian subfamily (Meliphaginae),
which it closely resembles, by the less specialized Oriental Aegithininae.
All have the ectethmoid winged, foramen single, and lacrymal fused.
The tongue is only weakly quadrifid in the Aegithininae.
AUSTALXAN HON3/4-ATRS (MLxeIaGxNa).--Diagnosis: Muscle pattern (figure
12) similar to that of the Cisticolinae in Melidectes and Melipotes, but M7b loses
pinnate character in the typical, slender-billed forms. M6 bifid (trifid and pinnate
in Philemon), protractors M1 and M2 expanded. Bill un-notched, operculate,
without rictal bristles. Tongue tubular, whipped out into long, quadrifid tip.
Palate with central ridge often grooved and posterior ridge usually trifid. Ten-
primatied nectar-feeders of the Australian Region. Species dissected: Acrulocercus
braccatus, Foulehaio carunculata, Melidectes fuscus, Meliphaga analoga, M. gracilis,
M. versicolor, Melipotes gymhops, Myzanthe melanocephala, Myzomela cardinalis, M.
melanocephala, M. sp., Philemon buceroides, Prosthemadera novaeseelandiae. Dis-
cussion: The loss of the pinnate character of M7b in more typical meliphagids may
be correlated with weaker adduction following stronger protraction (in Acrulocercus,
M2 crowds M6 just as in starlings). Despite wide radiation in the Australian
sanctuary, this subfamily was eliminated elsewhere. Function: Philemon (figured)
is atypical, but its tritid M5 (possibly quadritid) suggests relationship to the Aegi-
thininae and Estrildidae. In this and other specialized genera, vacuum for nectar-
feeding is attained in a unique manner. The cross section A-A' (also C) shows the
grooved central ridge for closing the tubular section of the tongue, while pressure
from the ridge of the lower mandible creates vacuum by a nibbling action observed
in captive specimens. In Melipotes and Prosthemadera the central ridge is unspecial-
ized. Foulehaio, Myzomela, Prosthemadera, and Meliphaga have M4b split to accom-
modate a large palatine salivary gland.
IORA ~lkiho%x[m3'- AF=GITIqlNIN.
I-IONY-E-ATER ~p.{c.~ ME-LIPMAGINAE'
AUSTRALIAN WtAVFR~ [ TRILDIDAI
Fmvs 12. Characters in honey-eaters and weavers.
AXttXCAN I-IoIffIY-IATIRS (PROMIRO?INAI).--Diagnosis: Muscle pattern of
Promcrops is similar to that of the Meliphaginae (M7b parallel, M6 bifid); the shorter-
billed Hylia and Pholidornis have M7b pinnate as in the short-billed Melidectes and
Melipotes. Promcrops has the meliphagine trifid palatal boss. Tongue tubular
with quadrifid tip in Promcrops; grooved with truncate, quadrifid tip in Hylia,
similar in Pholidornis, but tip not clearly quadrifid. Bill un-notehed, long in Pro-
roetops, short in the others; opereulate; without rietal bristles. Promerops and
Pholidornis have rigid, sealy crown feathers, suggested by those of some Ploceinae,
especially Sporopipes. Ten-primaried African nectar-feeders. Species dissected:
Hylia prasina, Pholidornis rushiae, Promcrops cafer. Discussion: Pholidornis is
West African, Hylia widespread, both in forest; Promcrops is confined to the Cape
Region in ecological association with Protea flowers. The first two build pendant,
roofed nests; that of Promcrops is nearly roofed. Gliciphila modesta (one of the
Meliphaginae of New Guinea) builds a pendant, roofed nest (Rand, 1942; 357).
ORIINTAL I-IONIY-IATIRS (AIGITHININAI).--Diagnosis: Muscle pattern and
other internal features (figure 12) as above with pinnate M7b (also M7a in Aetho-
rhynchus), but nostril semi-opegeulate. Aegithina and Erpornis have M6 bifid;
Aethorhynchus, trifid and pinnate (like Philemon). Ten-primaried insect- and
neetar-feeders of the Oriental Region. Species dissected: Aegithina tiphia, Aetho-
rhynchus lafresnayi, Erpornis xantholeuca. Discussion: This timalioid group is not
related to the pyenonotine Irenini. Though less specialized than African and
Australian meliphagids, the semi-opereulate nostril is dose to that of the Australian
Manorina, and the long tip of the tongue in Aegithina and Aethorhynchus shows an
incipient quadrifid character. The whipped-out tongue of Erpornis is not clearly
quadrifid, and the species is included here only until it can be checked thoroughly;
it may be a babbler. Function: Aethorhynchus has a small, free lacrymal probably
associated with forward vision in this prying group. The palate approaches that of
the Ploeeidae. The survival of this group in competition with the Oriental sylvioid
neetar-feeders may hinge on its lack of specialization; except for the specialized
Promcrops, the same may hold for the African group.
WEAVERS.--Internal characters seem to confirm what Chapin (1917)
and Delacour (1943b) suspected, that the Australian weavers origi-
nated independently of the African weavers. The Estrildidae seem,
in fact, to have arisen from the Meliphaginae or Cisticolinae in Aus-
tralia, while the Ploceidae arose from the Promeropinae or Cisticolinae
in Africa. I am unable, on anatomical grounds, to agree with Chapin
that the Viduinae are a subfamily of the Estrildidae; they seem to be
a subfamily of the Ploceidae, parasitic on such estrildids as reached
Africa and radiated throughout its grasslands. Their inability to
reach Australia and their poorhess in species suggest a relatively late
origin from the Ploceidae.
WAXBILLS, MANNIKINS, GRASSFINCHES (ESTRILDIDAE).--Digzosis:
Muscle pattern (figure 12) derivable from that of the Cisticolinae, but
adductors M6 (trifid) and M7 pinnate; palatal retractors, expanded,
with large M4 and complex M3b (as in Turdidae). Ectethmoid
foramen double, lacrymal fused. Bill un-notched, broadly conical
with nostril recessed below shield-like posterior border; rictal bristles
virtually lacking. Tongue with ventral horn rolling inwards dorsally,
frayed on sides and tip. Palate with lateral ridges compressed inward
to fuse with central ridge, leaving posterolateral vaults. Ten-
primafled Old World seed-eaters. Species dissected: Estrilda angolen-
sis, E. melpoda, E. nonnula, Lonchura castaneothorax, L. striata, Padda
oryzivora, Parmoptila woodhousei, Pirenestes sanguineus, Poephila
gouldiae, P. guttata, P. modesta, P. ruficauda, Pytilia afra, Sporopipes
frontalis. Discussion: The high origin of M7 within the orbit and the
trifid M6 (quadrifid in the Ploceidae) are notable, as is the tendency
for these adductors to have advanced insertions on the mandible.
The double foramen, too, is not found in the Ploceidae. This group
could logically have stemmed from the Cisticolinae. Both the
Malurini and Estrildidae build similar domed nests in grass (neither
woven nor pendant as in Ploceidae), lay similar eggs, and tend toward
specialization in color of plumagc traits possibly reflecting a common
ancestor. It is possible that the Australian weavers could have
invaded Africa via Malaya because the grassland seed-niche there
was open (the Ploceidae may have arisen as forest types); but the
African grassland would not have been open to the Malurini because
of competition with the Cisticolinae which were already there.
WAVRmRDS, WHVDAHS, rc. (PLocmA).--Diagnosis: Muscle
pattern (figure 12) similar to that of the Estrildidae, but M6 quadrifid,
M7 shorter in both origin and insertion, and ectethmoid foramen
single. Tongue not rolled and only the tip frayed out. Palatal
ridges not fused and without posterolateral vaults. Bill un-notched
without shield, semi-operculate, virtually without rictal bristles. Ten-
primatied seed- and insect-eaters of the Ethiopian, Oriental, and
Palaearctic regions. Species dissected: (Ploceinae) Euplectes orix, E.
progne, Malimbus nitens, M. sp., Ploceus bicolor, P. cucullatus, P.
reichenowi; (Viduinae) Steganura paradisea, Vidua macroura, V. regia;
(Passerinae) Dinemellia dinemelli, Passer domesticus, P. griseus. Dis-
cussion: Aethorhynchus (Aegithininae) resembles the Ploceinae in-
ternally and externally, but each is considered a separate offshoot
from the Cisticolinae. The internal (see Diagnosis) and external
similarities suggest that the whydahs, etc. (Viduinae) have arisen from
weavers (Ploceinae); in both there is an eclipse plumage, and young do
not breed until the second year. The Viduinae are specific parasites
of waxbills (Estrildidae), their young imitating those of that group in
the marking of the mouth. Anomalospiza may belong to this group
(Bannerman, 1949), its parasitization of members of the Cisticolinae
paralleling that of some primitive neotropical cowbirds (Icteridae)
which usually parasitize close relatives (Friedmann, 1929). Dinemellia
is included in the subfamily Passerinae as a specialized rather than a
primitive form, but this "lumping" may not be justified. Too few
species have been dissected to consider seriously a detailed rearrange-
ment of this complex group. The finely-woven retort-shaped nests of
the Ploceinae may be an evolutionary elaboration on the clumsily-
woven nests of Cisticola, that of C. juncidis approaching the retort
shape. Function: Many weavers, particularly forest-dwellers, have
weaker bills than the typical seed-eating forms.
THE AMERICAN NINE-PRIMARIED ASSEMBLAGE.--It seems particu-
larly clear that the American nine-primaried families arose from the
vireos (Vireoninae), a subfamily of the Monarchidac. On anatomical
grounds, these primitive shrike-flycatchers appear to have given rise
to insect-eating wood warblers (Parulinae) and fruit-eating tanagers
(Thraupinae). The buntings (Emberizinae) apparently evolved from
the Parulinae, and in turn gave rise to the blackbirds (Icteridae) and
Oalapagos finches (Geospizidae). The finches of the Pyrrhuloxiinae
and Carduelinae and, on Hawaii, the highly adapted Drepanididae,
apparently evolved from the tanagers. In addition, both warblers
and tanagers independently produced nectar-feeders (Beecher, 195 lb).
Formerly these were included in a single family, the Coerebidae.
Evidently the families of this assemblage radiated to fill the food-
niches provided by flowering plants in the New World. The eeteth-
moid is usually winged, lacrymal fused, the single foramen becoming
double in Parulidae.
Viragos (VlmoNN).--Diagnosis: Muscle pattern (figure 13) similar to that of
the Monarchinae, but M6 trifid, M7a with temporal slip pinnate, M7b parallel
(except in Vireo altiloquus and V. olivaceus). Ectethmoid foramen large, single;
laerymal fused. Bill notched, semi-operculate with nasal and rictal bristles. Palate
similar to that of the Monarchinae, tongue with bifid tip. Ten-primaried (tenth
variable, ninth often long) insect-eaters of the New World. Species dissected:
ttylophilus decurtatus, tt. hypoxanthus, tt. olivaceus, tt. poicilotis, Vireo altiloquus, V.
fiavifrons, V. griseus, V. olivaceus. Discussion: Internal characters relate the
vireos to the Monarchidac, but both these shrike-flycatcher groups are similar in
behavior. Some monarchs occasionally nest in a horizontal forklike vireos. Plumage
resemblances are less convincing; but the vireos have evidently been isolated from
monarchs throughout the Tertiary, so close external resemblance cannot be expected.
M7b is pinnate in only two species of vireos, but it is strongly pinnate in the Cycla-
rhini, which are strongly shrike-like. It is also pinnate in the Parulinae. The
advance of M3a on the mediopalatine clasp is an assemblage character. ttylophilus
poicilotis with pinnate M6, 3/I1, and M2 and un-notched bill is adapted to nectar-
feeding, but its muscle pattern approaches that of the Cyclarhini.
SaRm-Vmos (C3/4cAmN).--Diagnosis: Muscle pattern (figure 13) similar to
that of ttylophilus poicilotis and Vireo but muscles more massive, 21/I1, M6, and 21/I7
(including M7b) fully pinnate. Bill shrike-like; and horny palate relatively short,
614RIKE- VIR50"'C.,'r.,., %W%.'t'v;.'" CYCLARI-IINI
FmUR 13. Characters in vireos, tanagers, and warblers.
narrow, and deep. Species dissected: Cyclarhis gujanensis, Smaragdolanius pulchellus.
Discussion: This is a strongly shrike4ike Neotropical group whose resemblance to
the parallel Old World pachycephaline Falcunculus was shown by Naumburg (1925).
It presumably includes Vireolanius. Function: Adductors and palatal retractors
strongly developed as in other shrikes, but details betray vireo origin.
WARBI,RS, BJIGS, C. (PARJI,ID).--The efficiency of the
warblers in occupying insect-, fruit-, and nectar-niches is further re-
fleeted in the origin of the buntings from them; and in turn, the evolu-
tion of the adaptable blackbirds and Galapagos finches from the
buntings.
Woo) W.Rm,RS (PtmJLiu).--Diagnosis: Muscle pattern (figure 13) similar to
that of the Cyclarhini, but less massive and M3a farther advanced. Ectethmoid
foramen double or constricted; laerymal fused. Bill un-notched (usually), narrow
or broad, semi-operculate, with rictal and sometimes nasal bristles. Palate with
conspicuous posterior ridge, lateral ridges disappearing posteriorly. Tongue with
bifid tip. Nine-primaried (tenth small, rotated dorsally) insect- and nectar-feeders
of the New World. Species dissected: Basileuterus leucoblepharus, Dendroica aestiva,
D. coronata, D. discolor, D. fusca, D. palmarum, D. pensylvanica, D. petechia, D.
tigrina, D. virens, Geothlypis trichas, Granatellus venustus, Icteria virens, Mniotilta
varia, Myioborus brunneiceps, Oporornis formosus, O. philadelphia, Parula americana,
P. pitiayumi, Protonotaria citrea, Seiurus aurocapillus, $. noveboracensis, Setophaga
ruticilla, Wilsonia pusilla. Discussion: Broad-billed flycatcher-warblers like Seto-
phaga, Myioborus, and Basileuterus appear to be primitive with parallel M7a and
strong rictal and nasal bristles--in all of which they recall monarchs. Function:
Wood warblers are the most slender-billed oscines with fully pinnate adductors. The
efficiency of the pinnate adductors has permitted the reduction in mass of both muscle
and bone in the head region, and this, I think, is responsible for their adaptive success.
Segregation into adaptive tribes, aside from the Coerebini, calls for further anatomical
study.
WA, HomY-cms (Com,Ni).--I have elsewhere (Beether, 1951b)
given reasons for sinking the family Coerebidae and dividing its members between
the warblers and tanagers. The present tribe agrees with warblers in all internal
and external characters. Species dissected: A teleodacnis leucogenys, Coereba flaycola,
Conirostrum rufum. Function: Protractors M1 and MZ are expanded, an adaptation
for prying in flowers. The tip of the tongue is whipped out.
BJNNaS (EIZINA).--Diagnosis: Muscle pattern (figure 14) similar to that
of the Parulinae, but the insertion of the median slip of M6 advanced on the mandible
at the expense of pinnate M7b. Large M4a overlying M4b. Ectethmoid foramen
double or constricted; laerymal fused (except in Phrygilus and Lophospingus). Bill
un-notched, conical, semi-operculate, with rictal bristles. Palate with parallel
anterior and lateral ridges terminating in a posterior boss for occlusion with the tomia
of the lower mandible. Tongue slender, tapering to a short, bifid tip. Nine-primaried
seed- and insect-eaters of the New and Old Worlds. Species dissected: Amaurospiza
concolor, Ammodramus savannarum, Arremon fiaviventris, Atlapetes pileatus, Calamo-
spiza melanocorys, Calcarius lapponicus, Chondestes grammacus, Coryphospingus
pileatus, Cyanocompsa cyanea, Emberiza fiaviventris, Guiraca caerulea, Junco hyemalis,
J. oregonus, Melospiza georgiana, M. lincolni, M. melodia, Oryzoborus angolensis,
Passerculus sandwichensis, Passerella iliaca, Passerina amoena, P. ciris, P. cyanea, P.
leclancheri, Phrygilus fruticeti, P. unicolor, Pipilo chlorura, P. erythrophthalmus, P.
fuscus, P. ocai, Plectrophenax nivalis, Pooecetes gramineus, Poospiza erythrophrys, P.
nigro-rufa, $pizella arborea, $. passerina, $. pusilla, Zonotrichia albicollis, Z. capensis,
Z. coronata, Z. leucophrys. Discussion: The North American buntings examined
are specialized, with the insertion of M6 advanced and the exoccipital inflated--and
all except $pizella pusilla and $. passerina (which may not be close to $. arborea)
tend to have a long hind claw for scratching. A primitive Neotropical group, con-
taining the genera Coryphospingus, Passerina, Phrygilus, and Poospiza, has M not
advanced (unlike figure 14), approaching the paruline pattern. The insertion of
is somewhat advanced in Arremon and Ammodramus as in the Holarctic or Palaearc-
tic genera Calcarius, Emberiza, and Plectrophenax. All of these are likewise primitive
in having the exoceipital uninflated or but slightly inflated, and none scratch for
food. The American blackbirds are believed to have arisen from primitive Andean
types like Phrygilus with the insertion of M not advanced, thus similar to that of
the cowbirds. Phrygilus also has plumage patterns paralleling those of the Icteridae.
The advanced insertion of M may be an adaptation for cracking seeds against the
central boss.
Probably related to these Andean types are the primitive, mainly black "sporo-
phfline" finches (Bcecher, MS) which seem to be convergent with the Pyrrhuloxiinae,
especially in bill form. Species dissected: Catamenia analis, $porophila aurita, $.
moreletti, $. nigro-rufa, Tiaris bicolor, T. canora, T. olivacea, Volatinia jacarini.
Oryzoborus and Cyanocompsa (probably part of this complex) have the insertion of
M advanced. In Catamenia and $porophila, as well as in Amaurospiza, the inser-
tion is slightly advanced. The palate and external features suggest that Melanospiza
richardsonii may belong here and may have come from the same stock as the
spizidae.
GALAPAGOS FINCHES (GEosl'IZIDAE).--Diagnosis: Muscle pattern
(figure 14) as in Phrygilus with the insertion of M6 not advanced, M7b
pinnate. Slot-like ectethmoid foramen single or double, lacrymal
fused. Bill narrow, massive to slender, semi-operculate, with rictal
bristles reduced. Palate emberizine, but with slight relief; tongue
emberizine. Species dissected: Camarhynchus parvulus, C. prosthe-
rnelas, Certhidea salvini, Geospiza assirnilis, G. conirostris, G. fortis, G.
fratercula, G. scandens, G. strenua. Discussion: In the palate and
externally Melanospiza richardsonii (Santa Luria) is similar to Geo-
smsa, and both may have been derived from a widespread Caribbean
form like Tiaris. The Pliocene Gulf Stream could have rafted the
ancestor of Geospiza through the Panama Water Gap to the Galapagos
almost as readily as it might be airborne. I agree with Sushkin (1925)
that Certhidea is an insect-eating Galapagos finch rather than a warbler.
Adaptive radiation also has produced the nectar-feeding G. scandens,
insect-eating Camarhynchus, and fruit-eating G. crassirostris.
AMERICAN BLACKBIRDS (IcTERIDAE).--Muscle pattern (figure 14)
similar to above and to Andean Emberizinae but M7b complexly pin-
nate (not shown in Beecher, 195 la). Ectethmoid foramen constricted;
lacrymal fused (except in $turnella and Pezites). Bill un-notched,
GALAPAG0$ IhlCI-I~e5 %{ ' G0SPIZ1DA]
Fau 14. Characters in buntings, Galapagos finches, and American blackbirds.
conical to slender, semi-operculate (operculate in Amblycercus), gen-
erally without rictal bristles. Palate varying on emberizine pattern.
Tongue similar to that of Phrygilus but often whipped out as an
adaptation for flower-feeding (orioles, oropendolas, others). Nine-
primafled New World seed-, fruit-, and insect-eaters. All 38 genera
(including Spi.a) dissected. Discussion: Bill un-notched, without
rlctal bristles, and the capacity to expand the protractors M1 and
may have pre-adapted this group for radiation into virtually all the
food-niches open to passerinc birds in the New World.
TANAGERS, GROSBEAKS, SISKINS (THRAUPIDAE).--The tanagers
seem to have arisen from vireos with parallel M7b and with specializa-
tion of plumage color similar to that noted in the Cyclarhini. Two
subfamilies of finches, the Pyrrhuloxiinae and the Carduelinae,
evolved from the tanagers in the New World with little disjunction
and in a parallel fashion. In addition, the tanagers gave rise to a
tribe adapted for feeding on nectar (the Dacnini, formerly included in
the Coerebidae) and apparently provided the ancestral stock which
radiated in Hawaii to produce the nectar-, fruit-, insect-, and seed-
eating drepanidids.
TANAGERS (THRAUPINAE).--Diagnosis: Muscle pattern (figure 13) similar to that
of the vireos but M6 always pinnate, M7 (not M7b) progressively becoming pinnate
in advanced forms so that Tanagra is close to the Carduelinae in this and in the
advance of the insertion of the median slip of M6 on the mandible (Beechef, 1951b).
Bill notched, generally broad, with rictal bristles; nostril semi-opcrculate or feathered.
Ectethmoid foramen usually single, lacrymal fused (free in some species of Thraupis
and Calospiza). Palate with central ridge short, posterior ridge almost lacking, and
lateral ridges continuous posteriorly. Tongue sire'ilar to that of the vireos. Nine-
primatied New World fruit- and nectar-feeders. Species dissected: (unspecialized,
as figured) Calospiza artbus, C. chilensis, C. cyanoptera, C. desmaresti, C. guttara,
Ramphocelus bresilius, R. carbo, Thraupis bonariensis, T. cyanocephalus, T. palmarum,
T. virens; (approaching Carduelinae with advancing insertion of M6) Chlorophoneus
cyanea, tlabia gutturalis, ti. rubica, Nesospingus speculiferus, Stephanophorus dia-
dematus, Tanagra chlorotica; (approaching Pyrrhuloxiinae with insertion of M6 not
advanced) Cissopis leveriana, tlemispingus frontalis, tlemithraupis guira, ti. sp.,
Spindalis gena. Discussion: The variability of tanagers parallels that of wood
warblers, reflecting enormous adaptive potential, but the heavier bills and muscula-
ture suggest the crushing function of fruit-eaters.
SWXLLOW TXNXCERS (TERsNINI).--Tersina viridis is anatomically close to
Calospiga, and is a broad-headed fruit-eater nesting in holes in the ground. I regard
it as a tribe of the tanagers.
PLUSH-CAPPED TANAGERS (CATAMBLYRHYNCHINAE).--In the absence of anatomical
specimens this group is tentatively presumed different enough to merit subfamily
status.
T.N.GER HONEY-EATERS (D.CNINI).--This tanager element of the "Coerebidae"
is treated here as a tribe, convergent with the warbler tribe Coerebini. Species dis-
sected: Chlorophanes spiza, Cyanerpes cyanea, Dacnis cayana, Diglossa plumbea,
Euneornis campestris, Hemidacnis albiventris, Iridophanes pulcherrima. Function:
The generally longer, un-notched bills are adapted for probing deeper flowers than
the bills of the Coerebini. Apparently this is done without prying, since M1 and
M2 are weak.
CARDINAL GROSBEAKS (PYRRI-IULOXIINAB).--Diagnosis: Muscle pattern (figure 15)
massive with M1, M6, and M7 (not M7b) pinnate. Oval ectethmoid foramen single,
lacrymal fused. Bill massive, un-notched, generally with rictal bristles; nostril non-
operculate. Palatal ridges continuous posteriorly, tongue cylindrical. Nine-
primaried New World seed-, fruit-, and bud-eaters. Species dissected: Loxigilla
violacea, Melopyrrha nigra, Pheucticus ludovicianus, P. melanocephalus, Pitflus
grossus, Pyrrhuloxia cardinalis, P. sinuata, Saltator atriceps, S. atricollis. Discussion:
The first two species are here considered convergent with the sporophiline group
(Emberizinae) but may really belong in that group. The grosbeaks emerge so
gradually out of the variable tanagcrs that even anatomically it is difficult to draw a
I-IOUSE laINCFI ~ ax c CARDL1NAF
Fiatm 15. Characters in pyrrhuloxine, cardueline, and drepanidine finches.
boundary line. I agree with Mayr and Amadon (1951) that Richmondena is con-
generic with Pyrrhuloxia. Function: The massive bill and musculature are the
culmination of the crushing function suggested in the tanagers.
LINNETS, SISKINS, ETC. (CARDUELINAE).--DicgrOSiS: Muscle pattern (figure 15)
similar to that of the tanager Stephanophorus; M1, M6, and M7 (not M7b) pinnate,
insertion of massive median slip of M6 advanced on the mandible. M3b complex
as in the Turdidae. Single ectethmoid foramen slot-like, lacrymal fused. Bill
un-notched, conical, with rictal bristles; nostril feathered. Palate as in the Pyrrhu-
loxiinae but with short ridges between the central and lateral ones posteriorly.
Tongue cylindrical, its horny sheath with edges nearly meeting in the mid-line
dorsally. Nine-primaried fruit-, bud-, and seed-eaters of the New and Old Worlds.
Species dissected: Carduelis carduelis, Carpodacus mexicanus, C. purpureus, Cocco-
thraustes coccothraustes, Fringilla coelebs, Hesperiphona vespertina, Leucosticte griseo-
nucha, Loxia leucoptera, Loximitris dominicensis, Pinicola enucleator, Pyrrhula
pyrrhula, Spinus pinus, S. tristis. Discussion: Sushkin's (1925) recognition of the
subfamily Fringillinae for the chaffinch (Fringilla coelebs) is not supported; the
modification of the bony palate from the cardueline pattern is the result of the
enlarged palatine salivary gland probably in adaptation to more frugivorus habits.
Mayr and Amadon's (1951) proposal to apply this name to the present group is not
adopted because the term, Fringillidae, has been used for a polyphyletle family.
Logically, it would be better to suppress the term and its root in formal taxonomic
papers and to recognize the several finch groups as subfamilies of the warblers and
tanagers as outlined above. I am not in favor of changes of family names on a
purely nomenclatorial basis. Simpson (1945: 30) has pointed out that the Inter-
national Rules do not call for observance of priority in forming supergeneric names.
Had I constructed the names of the higher categories from type genera chosen by
priority, the superfamily Timalioidea would become Passeroidea, the family Thrau-
pidae would become Fringillidae, the subfamily Carduelinae would become
Fringillinae. It would be impossible to use Monarchidae as a new family name,
reducing older families to subordinate positions. Each of these changes would result
in a name with confusing connotations and would serve no useful purpose whatever.
In the case of the Monarchidae, taxonomy (so interpreted) would stand in the way
of doing what must be done. I agree with Simpson that taxonomic principles for
higher categories should be guided by general usage, common sense, and technical
convenience. Function: The massive M6, with its advanced insertion in all genera
except Loxia, insures maximum adduction. The hawfinches have posterotateral
palatal vaults occluding with the posterior part of the tomia of the lower mandible in
a mortar-and-pestle ftmction.
HAWAIIAN HONEYCREEPERS, FINCHES (DREPANIDIDAE).--From
what has been said of the fruit-, nectar-, and seed-adapted groups of
the Thraupidae, we might predict the result of uncontested coloniza-
tion of the Hawaiian Islands by an unspecialized tanager similar to
Piranga. At any time between the Eocene and Pliocene such an an-
cestral form could have been rafted by the Gulf Stream through the
Panama Water Gap and carried to Hawaii, though it was more likely
airborne. If the islands emerged in the Pliocene (Stearns, 1946), radia-
tion into the food niches could presumably take place rapidlyin the vir-
tual absence of competition, the special bill forms of the nectar-feeders
reflecting the peculiarities of the Hawaiian flora. A generalized
tanager stock similar to Piranga could evolve in two directions. The
bill could become lengthened to produce nectar-feeders and probers
(the counterpart of the Dacnini)_ or thickened for feeding on seeds and
buds (the counterpart of the Carduelinae). Amadon (1950b) divides
the Drepanididae into two such groups.
HAWAIIAN IINCHS (Psxx'rmosTRxNa).--Diagnosis: Muscle pattern (figure 15)
like that of Carpodacus, but more massive. Other internal features also similar,
but central palatal ridge short as in tanagers, rictal bristles further reduced. Species
dissected: Psittirostra cantans, P. psittacea. Discussion: The striking similarity of the
Hawaiian finches to the cardueline finches in all but plumage suggests parallel
development from isolated segments of the thraupine stock.
HAWAIIAN NCrARq*DRS (DRP*Nmnq*).--Diagnosis: Muscle pattern
(Beether, 1951b) like that of tanager nectar-feeders (Dacnini), but the longer, heavier
bills and large M1 and M2 indicate prying. Species dissected: ttimatione sanguinea,
Vestiaria coccinea. Discussion: ttimatione shows advanced insertion of the median
slip of M6 as in tanagers, a feature culminating in the condition in Psittirostra. I
examined ttemignathus lucidus briefly and, without making direct comparison,
thought it like ttimatione and Vestiaria. But Areadon says it is close to Psittirostra,
and I cannot say he is incorrect.
THE TIMALIID ASSEMBLAOE.--Although the term "assemblage" is
usually applied to a group of families in this paper, it is here used to
emphasize the adaptive potential of a single family. The existence of
shrike-babblers, lark-babblers, and tit-babblers suggests the unprece-
dented number of adaptive "tribes" which evolved from it. These
cannot be defined anatomically without dissecting many more species
than exist in present spirit collections. The Timaliidae might be
considered the stem group of the Timalioidea, since the Cisticolinae
(somewhat more primitive) is a transitional group, as much a sub-
family of this family as of Sylviidae. Revision by Delacour (1946).
BABBLERS (TIALIIDAE).--Diagnosis: Muscle pattern (figure 8)
similar to that of the Cisticolinae but outer slip of bifid M6 longer than
inner and M7 with very high origin inside the orbit. Ectethmoid
winged, foramen single, laerymal fused. Bill notched, operculate or
semi-operculate, with rictal bristles. Palate and tongue similar to
those of the Cisticolinae. Ten-primaried Old World insect- and fruit-
eaters. Species dissected: Alcippe nipalensis, A. sp., Chrysomma sinen-
sis, Cinclosoma ajax, Crateroscelis murinus, Daphoenositta miranda,
Eupetes coerulescens, Garrulax leucolophus, G. vassali, Laniellus leu-
cogrammicus, Leiothrix argentauris, Leioptila capistrata, Macronus
rubricapilla, M. sp., Malia grata, Neomixis tenella, Orthonyx spini-
cauda, Pellorneum ignotum, P. tickelli, Picathartes oreas, Pomatorhinus
montanus, Psophodes olivaceus, Siva cyanuroptera, S. strigula, Stachyris
chrysaea, S. nigriceps, Turdinus brevicaudatus, T. crispifrons. Dis-
cussion: Picathartes is unusual in its trifid pinnate M6, but I now agree
with Delacour and Amadon (1951) as to its timaliine status. Malia
dearly belongs here rather than with bulbuls or thrushes. Cinclosoma
and Eupetes are slender-billed, narrow-skulled terrestrial forms with
free lacrymal and, probably, forward vision; in them the pinnate
character of M7b has virtually disappeared as it has in many honey-
eaters and in the true wrens. Leioptila capistrata, reported by
Deignan (1945) as investigating blossoms, has a tongue partially
adapted to nectar-feeding. Laniellus of Java is a timaliine shrike;
Daphoenositta of New Guinea is a timaliine tree creeper. Since the
Laniidae and Sittidae are of timalioid origin, these attempts of Timalii-
dae to fill their niches in isolated regions are not strange. In fact it
seems almost certain that many Australian forms which ornithologists
have tried to link with groups occupying the same adaptive niche
elsewhere (e.g. Climacteris, Neositta) are Timaliidae.
THE PIPIT, LARK, PARROT-BILL ASSEMBLAGE.--The pipits and
larks seem to be parallel timalioid families arising from the Cistico-
linae with the loss or reduction of the tenth primary and possessing
plumage counterparts in the Monarchinae--a group of similar origin
but different niche. Alauda and Anthus resemble Cisticola in their
streaked pattern; Rremophila resembles Motacilla, Rhipidura, and
Platysteira in recognition pattern. All four groups habitually wag
or open and close the tail. The parrot-bills are basically similar to
larks and pipits in muscle pattern, bill, palate, tongue, and (Panurus)
reduction of the tenth primary. All have the ectethmoid winged,
foramen single, and lacrymal fused.
PIPITS, WAGTAILS (MoTACILLIDAr).--Diagnosis: Muscle pattern
(figure 16) similar to that of the Cisticolinae but M6 becoming trifid,
Ma advancing its insertion on the mediopalatine clasp, and the rather
massive M7 advancing its insertion on the mandible. Bill weak,
slightly notched, with the culmen abruptly arched above the semi-oper-
culate nostril; rictal bristles present. Palate similar to that of Cisticola
but tongue trough-like, quadrifid at tip. Nine-primaried (ninth elong-
ate) world-wide insect- and seed-eaters. Species dissected: Anthus
hodgsoni, A. pratensis, Motacilla alba, M. citreola, M. ocularis. Discus-
sion: M. citreola is very thin-billed, and its loss of pinnate character in
M7b illustrates the same adaptive situation noted in Meliphagidae.
LARKS (ALAUDIDA).--Diagnosis: Muscle pattern (figure 16) simi-
lar to that of the Motacillidae but M6 bifid, M3a not advanced, M4
and M7 massive, the latter pinnate in all parts. Long postorbital
process fused to suprameatic process. Bill un-notched, slender to
conical with feathered nostril and rictal bristles. Palate as above but
central ridge meeting posterior one in forms with a shorter bill.
Tongue similar but with truncate, quadrifid tip. Ten-primaried
(tenth reduced, ninth elongate) world-wide seed- and insect-eaters.
Species dissected: Alauda arvensis, Calandrella minor, Eremophila
alpestris, Galerida cristata, Melanocorypha yeltoniensis, Mirafra assami-
cus. Discussion: The larks seem to have originated from the Cistico-
linae close to the pipits, monarchs, and parrot-bills. Function:
Meinertzhagen (1951) observes that larks swallow seeds whole with
grit, noting that the thick-billed Rhamphocorys does not have a very
powerful "bite." Notably missing is the angulated commissure which
in seed-cracking finches aligns the tomia or cutting edges of the bill
more nearly at right angles to the pull of the palatine retractors so that
they can assist the adductors. The weakness of M6 in larks is com-
pensated for by the intrusion of massive M7 into the orbit, and the
fusion of the postorbital and suprameatic processes may simply pro-
vide greater surface for its origin. The peculiar, scutellated tarsus of
this group is regarded as a unique specialization and not accorded
much weight. Apparently some members (e.g. Eremophila) have
lost the tenth primary.
WREN-TIT, PENDULINE TIT, PARROT-BILL (PARADOXORNITHIDAE).
--Delacour's (1946) proposal that the Wren-fit (Chamaea) is close to
the parrot-bills is supported by internal characters, but I prefer to
recognize the Paradoxornithidae as a family rather than reduce the
group to a tribe (Chamaeini) of the Timaliidae. It may be practicable
to recognize two subfamilies--the Paradoxornithinae for the parrot-
bills and wren-fit and the Aegithalinae for the Bush Tit (Psaltriparus)
and the Penduline Tit (Aegithalos). (cf. Mayr and Amadon, 1951).
PamtoT-Bmus (Pa.taDOXOmITmNAE).--Diagnosis: Muscle pattern (figure 16)
and other internal features similar to those of the Alaudidae, especially in Suthora, but
post-orbital process short. Bill un-notched, thin in Chamaea to parrot-like in Para-
doxornis, the curved upper mandible notably heavy, with rictal bristles; nostril non-
operculate, leathered (Chamaea semi-operculate, unfeathered). Palate with an-
terior and posterior ridges separate in Chamaea, fused in parrot-bills, but the posterior
ridge trifid posteriorly in all. Tongue long in Chamaea, short and truncate in parrot-
bills but always quadrifid at tip. Ten-primaried Old World insect- and seed-eaters
represented by Chamaea in the New World. Species dissected: Chamaea fasciata,
Panurus biarmicus, Paradoxornis unicolor, Suthora verreauxi. Discussion: The
generic variations are on a gradient, and there is no doubt of the homogeneity of the
group. As in larks, a lack of angulation in the commissure might prevent evolution
of a true finch type, and traces of the black recognition pattern in parrot-bills suggest
relationship with larks. They may belong in the same assemblage, but are here
regarded as distinct adaptive branches arising from the Cisticolinae. Function: the
parrot-bills are ecologically associated with great reed beds, and the bill is used
particularly for tearing reeds apart to obtain insects (Caldwell and Caldwell, 1931).
LONG-TAILED AND BUSH TITS (AEGITHALINAE).--'Diagnosis: Similar to above but
M5 pinnate and M3a advancing its insertion on the mediopalatine clasp. Species
dissected: Aegithalos caudatus and Psaltriparus rainlinus. Discussion: In the habit
of building roofed, pendant nests, unlike the cup-shaped nests of the Paradoxorni-
thinae, these birds apparently converge with the Remizinae of the true titmice.
WREN, CREEPER, TITMOUSE ASSEMBLAGE.--These families have
the protractors M1 and M2 expanded for bill prying, and seem to
stem from each other in the sequence: Troglodytidae--Certhiidae
Sittidae--Paridae. M7b might be considered parallel but not in the
same sense as in Sylvioidea. In the wrens and creepers with their
slender bills this muscle seems to be just at the point of entirely losing
its pinnate character, as has occurred in slender-billed species of
FtOI:.N ED LARK ~ % 'cx ~ ALAUDI DA m'
PIPIT ~ 'lk.k X-%,x"' PIOTAC1LLIDAF
'TIT ~ C, %(xax ~PARADOXORNITHIDA
FmuaE 16. Characters in wren-tits, titmice, pipits, and larks.
Timaliidae and Meliphagidae (below). If so, according to Dollo's
Law (Gregory, 1936), power would need to be re-acquired in a different
way in the derived thicker-billed Sittidae and Paridae. It happens
that in members of these latter families the fibers of M7b insert on a
broad aponeurosis that is apparently the functional equivalent of a
pinnate M7b, possibly the substitution product of new gene loci. In
designating this assemblage as timalioid, I have been influenced by the
split M4b (never found in Sylvioidea), horny palate (as in the assem-
blage above), and timaliid plumage type. The nervousness and habit
of carrying the tail over the back would be weak evidence alone but
tend to support the verdict of the other characters--along with
grassland, desert, and brush habitat--that Troglodytidae and Ma-
lurini (Australian wrens) arose independently from the Cisticolinae.
Competition with these other groups in the Old World could have
largely eliminated the Troglodytidae there, while the open niches of
the New World could have permitted wide radiation. The families
of this assemblage are primarily hole nesters or dome-nest builders.
WmNs (TRoaioi)3/4ii)A).--Diagnosis: Muscle pattern (figure 17)
similar to that of the Malurini but M7b not clearly pinnate. Ecteth-
moid plate truncate and falling short of zygoma as in Malurini;
foramen single, lacrymal fused. Tongue slender, with quadrifid tip.
Palate with slight vault between central and posterior ridges in
Troglodytes; these ridges continuous in Heleodytes. Bill slender, gen-
erally un-notched, operculate, without rictal bristles. Ten-primaried
insect-eaters of the New World and the northern parts of the Old
World, with streaked or barred plumage. Species dissected: Cisto-
thorus stellaris, Heleodytes fasciatus, Telmatodytes palustris, Tro-
glodytes aedon, T. musculus. Function: Narrow interorbital distance,
taken with the short ectethmoid and lack of rictal bristles, suggests
unusual forward vision in wrens, which feed in close quarters where
lateral vision as used in "rapid peering" may be ineffective.
CRPS (C(miDA).--Diagnosis: Muscle pattern (figure 17)
similar to that of the wrens but greater expansion of protractors M1
and M2. Other internal characters as in wrens. Bill similar but
decurved, unmotched. Tongue still more slender than that of a
wren, quadrifid. Palate with posterior ridge "open" but in many
ways intermediate between that of the wrens and that of the titmice.
Ten-primaried tree-creepers, mainly Holarctic, with streaked plumage.
Species dissected: Certhia familiaris. Discussion: Certhia with its
stiffened tail feathers is apparently the most specialized form. Rhab-
dornis, Salpornis, and Tichodroma are considered primitive members
of the group, but Climacteris is believed to be an endemic Australian
IRSN ~ Tkkz uculu ~ TIRO6LODYTIDA5
17. Characters in wrens, creepers, nuthatches, and verdins.
timaliid genus. Muscle pattern, modifications for forward vision,
slender bill, and plumage seem to link the creepers to the wrens, and
the wall-creeper Tichodroma suggests a transition between creepers
and nuthatches. Function: The slender bill seems to act as a curved
forceps for probing bark-crannies "roofed" from the weather, and the
prying musculature is probably as strong as the bill structure will
stand.
NVTHtTCHS (SI7C7cI)t).--Diagnosis: Muscle pattern (figure 17)
advanced over that of the Certhiidae, with protractor M1 partly
pinnate and M2 expanded over the interorbital septurn, M3b slightly
advanced, M4a enlarged, M7 pinnate, except M7b which is covered
by an aponeurosis. Other internal characters similar to those of the
Certhiidae but lacrymal free, reaching zygoma, bill slightly recurred
with rictal bristles; nostril non-operculate. Tongue quadrifid.
Palate similar to that of the Paridae. Ten-primaried trunk-foraging
birds of world-wide distribution. Species dissected: Sitta canadensis,
S. frontalis, S. pusilla. Discussion: Hypositta (see above) seems to be
a vangid; Neositta and Daphoenositta are believed endemic timaliid
genera of the Australian region. Because of adaptive changes, it is
not certain that this group stems from Certhiidae. The palate, tongue,
and plumage in Tichodroma suggest at least a common stock. Func-
tion: In addition to its prying function, the enormous M2, so like that
of woodpeckers, may oppose the advanced M3b to snub the palate from
both directions for a shock-absorbing function in hammering. The
free lacrymal reaches the zygoma but may be moved aside for clearer
vision at the tip of the bill.
Tiraic (P.I)t).--Diagnosis: Muscle pattern (figure 16) similar
to that of the Sittidae but M2 less expanded, adductors more massive.
Ectethmoid truncate, foramen becoming double (pinched); lacrymal
fused. Bill un-notched, short, stout, with few rictal bristles; nostril
non-operculate, feathered. Tongue short with truncate, quadrifid
tip. Palate similar to that of Sitta but with flatter relief. Ten-
primaried insect- and seed-eaters of world-wide distribution, plumage
similar to that of the Sittidae. Species dissected: Aegithaliscus anna-
mensis, A. concinnus, Melanochlora sultana, Parus atricapillus, P.
bicolor, P. carolinensis, P. gambeli, Sylviparus modestus. Discussion:
Sylviparus is typical despite its thin bill. Function: Adduction is
greatly strengthened, and the broad ectethmoid suggests less forward
vision than in Sitta.
I)v.I TTs (lMlzx.).--Diagnosis: Muscle pattern (figure 17) similar to
that of the Paridae but protractors expanded (M1 pinnate); M4b split to accommo-
date a large palatine salivary gland as in nectar-feeders. Ectethmoid foramen
single, bill conical, without rictal bristles. Palate with boss at point of fusion of
central and posterior ridges; tongue elongate but quadrifid at tip. Ten-primaried
insect-, fruit-, and (I predict) nectar-feeders of world-wide distribution. Species
dissected: Artkoscopus sp., Auriparus flayJeeps. Discussior: Birds of this subfamily
of Paridac are adapted for prying (Lorenz, 1949), aud the pendant nest (convergent
with Aegithalinae) cttlminates in the gauze-like bag of the African genus A rtkoscopus.
EVOLUTIONARY IMPLICATIONS OF OSCININE RELATIONSHIPS
Comparison with Other Classifications.--Reviews of previous oscinine
classifications by Newton (1893-1896) and Stresemann (1927-1934)
show that earlier authors could not agree even as to which of the 60-
odd families were generalized and which specialized. Few ornitholo-
gists appeared to realize that a linear series is no classification at all.
Evolution is basically a process of divergence, and those who judged
the thrushes, crows, or finches to be the most specialized groups were
each right and each wrong. In a branching phyletic tree--the sim-
plest expression of relationships so far as they may be inferred from
morphology--all three, equally, are terminal groups. Lacking a
phylogenetic tree, there was no classification, only a list of families.
Modern ornithologists often show real insight into the relationships
of these families, however, and Mayr and Areadon (1951) do a great
service in "laying the cards on the table."
The present classification is based on the bird as a whole so far as
we know it. Far from cutting across external characters (except bill
form), the internal characters employed support and parallel them.
Whereas the few available external characters offer multiple choices in
deciding relationships, the anatomical characters offer limited ohoitc
both pointing up relationships and ranging groups from simple to
complex. The muscle patterns are not absolutely constant in every
family--taxonomic characters rarely are. But the adaptive increase
in the pinnate character of the jaw muscles in tanagers, for instance,
links them to the finches which evolved from them, as supported by
external lines of evidence such as color of plumage. These anatomical
characters often relate families not previously linked by ornithologists
but whose closeness on the basis of plumage is most convincing
(of. Beether, 1951b). This is because the classifications based on
superficial external characters laid great stress on bill resemblance, for-
getful of the evolutionary prerequisite that new lines, diverging from
an ancestral stock, must be differently adapted. Thus they failed as
a rule to group families naturally and had no basis for detecting
numerous cases of convergence. This gave an erroneous picture of
oscinine evolution.
Adaptive PotentiaL--Evolution is dynamic (of. Emerson, 1949;
640 if.). The competing stem groups of Sylvioidea and Timalioidea
seemed under constant pressure to evolve forms adapted for any food-
niche insufficiently exploited; and success, aside from accidents of
isolation, depended on adaptive potential. For instance, the babblers
(Timaliidae) seem to be a microcosm of the Timalioidea as well as the
stem group from which its specialized families arose (the transitional
Cisticolinae is as much a subfamily of Timaliidae as of Sylviidae).
The best check on the evidence that the Timaliidae has given rise to
shrike groups is seen in the existence of timaliine shrikes (Pteruthius,
Laniellus). A good check on timaliid origin for other groups is seen in
the occurrence of timaliine larks (Cinclorhamphus) in Australia where
true larks do not occur. Similar examples are seen in what I interpret
as timaliine titmice (Parisoma, Myioparus), creepers (Climacteris),
and nuthatches (Neositta). In the Sylvioidea, one of the best checks
on the indicated origin of swallows from flycatchers may be the
existence of the swallow-flycatcher (Artomyias). Similarly, the origin
of dippers from thrushes is made more plausible by the existence of
semi-aquatic chats, especially the forktail (Enicurus), internally
adapted like Cinclus for holding slippery prey. These adaptive types
are usually few in species and unspecialized when compared to major
groups with the same adaptation, characteristically arising where the
latter are absent.
Natural Assemblages.--It appears that the subfamilies of the stem
Sylviidae may have been differently pre-adapted to seize initial
advantages in the competition to fill food-niches made available by
flowering plants. Each has apparently given rise to one or more
natural assemblages of families with the adaptive potential to occupy
all or most niches, and the mglange of species actually filling them in
the present cross section of time is the result of a selection process
(of. Park, 1948).
The pinnate M7b of the Timalioidea may have conferred an initial
advantage in the race to evolve massive, pinnate adductors, for the
American finches and the Australian and African weavers all con-
vergently occupy the seed-cracking niche. Their associated nectar-
feeding groups may be a necessary link in the series leading to seed-
cracking, for only the sylvioid nectar-feeders, the Nectariniidae,
Dieaeidae, and Zosteropidae, with a very short, non-pinnate M7b, do
not have an associated finch group. This reduction of M7b may be
genetically deep-seated (in terms of pleiotropy) in all pycnonotine
assemblages, the reason crows did not evolve a finch despite otherwise
highly pinnate adductors. The shrike adaptation also calls for the
added power of a pinnate M7b, and there are no sylvioid shrikes.
On the other hand, the tendency for M3b to expand into a powerful
muscle with a distinct M. retractor palatini in the sylvioid thrushes and
starlings may have given them the edge in exploiting ground-niches
because of increased efficiency in securing slippery prey. A similar
development of this muscle has adapted thrashers for digging (Engels,
1940), linnets and weavers for seed-cracking.
Niche Divergence without Plumage Divergence.--Natural assemblages
always embrace groups differently adapted as to food-niche. A
striking example is seen in the divergence of the starlings (Sturnidae)
and swallows (Hirundinidae), which have very similar internal
characters, from the flycatchers (Muscicapinae), These groups have
evolved parallel plumage types, pointed wing, forward vision, and hole
nesting, but are different in their feeding habits. The starling is a
ground-feeder, the swallow an aerial feeder; yet forward vision and
pointed wing pre-adapt the introduced starling in North America to
take over the Purple Martin's niche when the latter flies south. On
warm fall days, it feeds in the air, fluttering and gliding like the
martin, but with frequent resting.
Again, the larks and pipits are ground-feeders, the monarchs and
fantails are flycatchers, yet most of the plumage types of the one have
counterparts in the other. There are many exceptions to this, but
anatomical characters suggest that both have arisen from the
Cisticolinae. The larks and pipits are streaked like the grass warbler
Cisticola and often have the head and breast recognition pattern of
Prinia fiavicans or P. pulchra. The tail-opening trait of the grass
warblers may have been transmitted genetically to these descendant
groups also. The groups arising from the Cisticolinae may be regarded
as a sort of super-assemblage, most of them with some suggestion of
the recognition pattern mentioned earlier. Moreover, all are either
differently adapted as to food-niche or, if not, appear to have arisen
in isolation from each other.
Evolutionary Rates.--Wherever particularly favorable conditions of
pre-adaptation, isolation, and niche-opportunity occur, a group may
radiate into new major lines. The vireos, the stem group of the nine-
primatied assemblage, are a good example of this. This group may
have evolved at a higher rate when first isolated in America to produce
the more adaptable warblers and tanagers whose success has narrowly
limited the vireos' present niche. Despite supposed greater age,
however, it remains a primitive "low rate" line with one-third as many
species as the warblers and one-sixth as many as the tanagers. When
we consider that each of the latter two has likewise given rise to several
finch groups with still greater numbers of species, it appears that rate
of evolution in this assemblage increases from the stem group to the
terminal group. This is at least partly due to niche opportunities pro-
vided by flowering plants.
That rate of evolution is not merely a function of relative abundance
of food types but actually signifies heightened adaptive potential
in "high rate" terminal groups seems strongly indicated. The Ameri-
can blackbirds (Beechef, 1951a), originating from emberizine finches,
were able to occupy virtually all passerinc food-niches in a relatively
short time, despite the competition of groups already occupying them.
The Galapagos finches (Lack, 1947), of emberizine origin, and the Ha-
waiian Drepanididae, of tanager origin, have done similatly, while the
(probably emberizine) finch Nesospiza (Lowe, 1923) seems to represent
the early stages of such an evolution on Tristan da Cunha. Now
there is no evidence that the Galapagos mockingbirds (Nesomimus) or
Hawaiian thrushes (Phaeornis) reached these islands later than the
finches, and I believe they were limited to relatively usual niches
(Amadon, 1950b) because they represent low-rate lines. Though
treated as a terminal group, the thrushes appear to be adaptively
restricted by virtual inability to evolve pinnate musculature, and the
history of oceanic faunas reveals no instance of such primitive coloniz-
ing groups embracing food-niches significantly "outside" their normal
ones. The fact is that all of these explosive radiations were accom-
plished by "high rate" lines, particularly finches.
Validity of the Phylogenetic Tree.--The significance of the above may
be that, through competition, the more recent, adaptable groups con-
fine primitive groups to the few niches they fill efficiently. If so, the
continued existence of the vireos and the entire sub-oscinine assem-
blage is the best evidence that for Oscines we can derive family from
living family in the present cross section of time. The morphological
tree may, therefore, approximate phylogeny--a tree in which dynamic
branches are still growing out of a relatively static trunk.
Island Effect.--I do not see a special problem in the larger bill-size
of island birds first noted by Murphy (1938: 538). The lesson of the
Galapagos finches is that an emberizine stock, small-billed in competi-
tion with large-billed tanager finches on the mainland, could escape
size restriction and could occupy all seed-niches in an island environ-
ment where competition is lacking. The larger-billed orioles of
Caribbean islands are probably utilizing large fruits and flowers
exploited by oropendolas on the mainland. Island forms, representing
fewer groups, extend their adaptive range of bill form and size, and
even low-rate groups can do the latter. Regarding the tendency
toward small size in Rennell Island birds, Hamlin (Mayr and Hamlin,
1931) has commented on the stunted nature of the general vegetation
324 Baacaaa, Phylogeny of Os1/2ines œ Auk
[Vol. 70
there. If fruits and flowers are smaller, I would suggest that asso-
ciated insects may also be smaller, reducing the size range of the whole
food-chain.
The Reality of the Higher Groups.--Internal characters fully support
the existence of the families as derived by ornithologists mainly
through the study of external characters, and this mutual support is
the best evidence that these two types of characters are not classifying
different parts but the organism as a whole. The recent revisions of
the Timaliidae and the Pycnonotidae by Delacour (1946; 1943a) are
supported and no very great transfer of species from or into either
is proposed on the basis of internal anatomy. The difficulty in dis-
tinguishing between the Sylviidae and the Timaliidae, experienced by
taxonomists working with external characters, is somewhat borne out
characters; the grass and bush warblers (Cisticolinae)
transitional between the two families and could be re-
subfamily of either. The value of internal characters is
group relationships, so that what were 60-odd equal
into a hierarchy of superfamilies, families, subfamilies,
Complexity of Terminal Groups.--The terminal groups occupying
the outer twigs of the phyletic tree (figure 18) are more complex than
the stem group, both anatomically and in degree of behavioral elabo-
ration (nesting, courtship, communal habits, etc.). These are
primarily the weaver and finch groups (particularly the icterids), the
crows, birds of paradise, bower-birds, and nectar-feeders--all of which,
by virtue of special qualification or favorable isolation (or both), have
undergone notable radiation. Primitive terminal groups which have
also achieved adaptive success with structural and behavioral elabo-
ration are shrikes (Vangidae, Cracticidae), isolated from competing
advanced groups.
Evolutionary Relationships.--In a phylogeny expressive of evolution,
the various sub-groups of seed-cracking birds are more dosely related
to primitive insect-eating groups than to each other. Their unusually
wide dispersal made possible by their diet of seeds gave taxonomists
a false impression of homogeneity not met with in fruit- or nectar-
eaters, the Old and New World groups of which do not generally over-
lap in range. Such convergence between members of the various
assemblages appears to be the rule. It may be very dose as in finches
or as between titmice and parrot-bills or superficial as between the
corvine and shrike assemblages. Even where partial, however, con-
vergence is probably always adaptive. The peculiar food-scratching
behavior of North American buntings, with unusual development of
the hind claw, occurs in African whydahs. Brood parasitism occurs
in African weavers and American blackbirds (Friedmann, 1950) and
forms of each, convergent in plumage, tend to occupy similar habitats
(Euplectes-Agelaius). The long straight hind claw of larks, pipits,
snow buntings, and longspurs may be an adaptation for locomotion
on mud (or snow), and the coucal (Centropus) has similar equipment
and inhabits muddy places. One hardly dares to propose that we see
in all of these cases of convergence the effects of homologous genes
(Spencer, 1949: 23), reflecting the close relationships of these passefine
families.
I find myself in rather close agreement with Pycraft (1907) on the
resemblances of shrike groups, though I draw different evolutionary
implications from them. He marks the similarity of Tylas and
Xenopirostris, both of which I include in Vangidae. He notes the
resemblance of Vireolanius to what I call the primitive shrikes and
of vireos to the Muscicapidae. I would say relationships of the
vireos are with the Monarchidae, which I remove from Muscicapidae,
and that the Vanginae, Prionopinae, Pityriasidinae, Cracticinae,
Artaminae, and Cyelarhini (including Vireolanius) evolved separately
from the Monarchidae as endemic shrikes in their respective faunal
regions. I recognize Wetmore's (1951) contention that Vireolanius
is a shrike but think it an endemic American shrike arising from the
vireos. As in finches, it appears that each of the shrike families is
more closely-related to the world-wide monarch-vireo group than to
each other. Conversely, the Australian honey-eaters (Meliphagidae)
must be expanded to include African and even Oriental groups.
Taxonomically, relationships seem more complex than was assumed
from external resemblance alone.
Origin and Dispersal.--Mayr (1946) stated the problem posed by
related barbets, trogons, and parrots isolated in the tropics of the Old
and New Worlds. It applies equally to the ancient suboscinine
assemblage apparently displaced into the southern continents by a
modern oscinine assemblage arising from it (of. Matthew, 1915). The
oriental Eurylaimidae, represented in Africa by the relict, Smithornis,
is probably close to the New World Cotingidae (Pycraft, 1905). The
Pittidae, Philepittidae, and Xenicidae show a notably disjunct dis~
tribution in the Old World tropics and must have been early separated
from the closely related Furnariidae, Dendrocolaptidae, Tyrannidae,
etc. of the New World tropics. Their sedentary habits virtually
require that all of the latter groups must have been in South
America before the Eocene Central American water gaps isolated it
from North America until the end of the Tertiary. The problem ap-
plies also to primitive members of the oscinine assemblage. The
nine-primaried American families arose to fill food-niches provided by
the flowering plants in isolation from Old World groups, so the stem
vireos may have reached America before the origin of flowering plants.
The vireos arose from the Monarchidae, and these shrike-flycatchers,
with the endemic primitive shrike groups arising from them (above),
show a mainly tropical distribution pattern. This world-wide, pan-
tropical pattern is often met in late Cretaceous groups (Beaufort,
1951). Sarasin (1910) notes 11 genera of reptiles and amphibians, 8 of
land mollusks, and 6 of terrestrial flatworms with similar distribution.
It is quite characteristic of skinks, iguanas, geckos, and boas, as well
as of primitive insectivores and lemurs among mammals, though
Simpson (1945) states that the relationships in these groups are still
problematical.
The dilemma of zoogeographers seeking a former tropical exchange
corridor at the north to account for these related, pantropical groups
is that Bering bridge has not been even subtropical as far back as the
Cretaceous (Stegmann, 1938; Chaney, 1940). Although Simpson
(1947) finds it adequate to explain Tertiary mammal distributions, the
above dispersals are believed to have occurred earlier--and even
Simpson admits the bridge favored cold-adapted forms. On the
other hand, there is a tropical angiosperm-gymnosperm flora in the
Upper Cretaceous of Greenland, elsewhere met only in the American
Potomac flora (Seward and Conway, 1935). This, with the subtropi-
cal floras of Western Europe and the London Clay in the Lower
Eocene (Reid and Chandler, 1933), suggests a milder climate in the
North Atlantic area. The latter flora, of Malaysian affinities, is
thought to have occurred on the north shore of the Tethys Sea as a
result of warm currents from the Indian Ocean (Brooks, 1926). The
Potomac flora implies Cretaceous contact of North America with
Greenland and possibly with the British Isles via Iceland, though not
necessarily all at one time.
Geological evidence has not eliminated the possibility of Mesozoic
drift of continents, and our understanding of faunal and floral rela-
tionships must be refined before this issue can be decided biogeographi-
tally. Since the velocity of the earth's rotation is 1000 miles per hour
at the equator and 0 miles per hour at the poles, North America and
northwestern Europe might have been in contact long after Africa and
South America had drifted apart. If such a connection existed as
recently as Upper Cretaceous, it would have been a tropical one, and
the tropical flora would have retreated toward the equator in the
several continents during the climatic deterioration following the
regression of Tethys Sea into the present Mediterranean. In so doing
it would have fragmented along with its faunas; and in Old and New
World tropical regions, thus separated, parallel evolution of static,
early-specialized groups (barbets, trogons, parrots) might be ex-
pected. But the generalized passedfie insectivorous stocks might
have tended to diverge rapidly in response to the available food-
niches provided by the flowering plants, evolving different assemblages
in the Old and New Worlds. However, most authors, like Darlington
(1948.), prefer the Bering bridge to its alternatives.
Other primitive insectivorous groups might have been expected to
enter America along with the suboscines and vireos. Polioptila,
Microbates, and Ramphocaenus may be relicts of a branch of the
world-wide Sylviidae that did not survive well in competition with the
American warblers. Ramphocaenus I regard as an American endemic
only convergent with the African Macrosphenus and the oriental
Orthotomus which it resembles. To have given rise to the Mimidae,
thrushes would have had to arrive early, and so would swallows.
Since wrens apparently are not related to thrashers, they may have
evolved in the Old World, where competition with grass and bush
warblers (Cisticolinae) early forced them into the grassland and desert
niches of the New World. The initial presence of wrens and thrushes
may have prevented extensive exploitation of the ground-niche by the
insect-eaters of the nine-primaried assemblage. Considerable diver-
gence of the Bombycillidae from the nearest Old World groups (bulbuls
and cuckoo-shrikes) suggests early arrival. But most Tertiary inter-
change after this initial period would have been by cold-adapted
species across the Bering bridge. Mayr's analysis of the North
American bird fauna (1947) is admirable and makes further discussion
here unnecessary, except that, since the "Old World" finches arose
from tanagers in the New World, their Eurasian radiation is secondary.
Its extent, however, suggests that the seed-cracking niche was vacant
in Eurasia and that the Ploceidae reached the Palaearctic rather late.
Faunal relationships and geology both indicate that the Ethiopian
and Oriental regions were in contact in the Upper Cretaceous when the
Deccan volcanism devastated 250,000 square miles of peninsular India,
isolating its southern tip and Ceylon. North of the Deccan, the
Tethys Sea extended from Europe to Africa, divided into northern
and southern components by a land mass extending from Africa to
northern India (Lake, 1939). The distinctive African relicts of primi-
tive groups like the Eurylaimidae, Pittidae, and Timaliidae (Pica-
thartes) and oriental relicts of the African Prionopinae (Tephrodornis)
suggest the early closure of this faunal bridge. Since the Timaliidae
are scarce and the Pittidae absent on Ceylon today, these groups may
have survived in a semi-isolated northern India, caught between the
rising Himalayas to the north and the Deccan to the south with a
receding Tethys on the west. Otherwise it is hard to account for the
species- and niche-radiation there. The smaller number of species in
the Australian Region may indicate isolation at the same time, but
their importance in occupying its niches cannot be over-emphasized.
The Pycnonotidae may also be an old Oriental group.
Faunal exchange was again possible in Miocene-Pliocene times when
forest covered most of Africa with a belt across Arabia to the Oriental
Region (Lonnberg, 1936; Beaufort, 1951). This accounts for the
similarity of the Ethiopian and Malaysian forest bulbuls, babblers,
and cuckoo-shrikes noted by Chapin (1932), who also thinks most
African savanna birds arrived via a savanna belt north of this forest.
I agree with him that the Malaconotinae and Laniinae could have
arisen in Africa and that the Ploceidae, Viduinae, and Cisticola may
have arisen in savanna south of the forest barrier, but I consider the
last three closely related. The Estrildidae, arising in Australia, first
entered the savanna north of the forest, in my opinion, and their
parasitization by the Viduinae may, thus, date from the joining of the
northern and southern savannas with regression of the forest in late
Tertiary times. The Viduinae are the only weaver group confined to
Africa.
CONCLUSIONS
The direct correspondence of all very early, world-wide distribution patterns with just those insectivorous passerine groups judged primitive on anatomical characters, the major assumptions of this work are confirmed. The fruit-, nectar-, and seed-eating groups, judged later in origin and more advanced, are of limited distribution, and this agrees with the separation of the faunal regions as the Tertiary unfolded. By their existence, these world-wide, primitive groups--confined mainly to insectivorous niches by the more advanced groups that apparently arose from them--make it less necessary to postulate extinct common ancestors for which we have no evidence and which probably were similar to modern sylviids. The morphological tree for the rapidly evolving Oscines may be a fair approach to a phylogenetic tree.
The working method, therefore, seems to be valid, and this arrangement of oscinine higher groups may be permissible as a first approximation. Allowance must be made for subjective judgements as to relationships between closely related groups in a still-evolving complex; but this is implicit in any classification, and we may hope for
refinement as our understanding grows. This first attempt at a phylogenetic arrangement of the Oscines is offered for appraisal in terms of present and future ornithological facts.
SUMMARY
An attempt is made to clarify the relationships of the higher groups (families) of oscinine birds and to erect a phylogeny based on the methods of comparative anatomy. Several independent lines of anatomical evidence in the head region, particularly the jaw musculature, are used, but external characters are also considered. The working method assumes that structurally simpler characters are primitive and an initial separation of the suborder into the super-families Sylvioidea and Timalioidea is based on a simple but constant muscle difference. Within each of these, the families are arrayed in a hierarchy of increasing general complexity as they become adapted to the fruit-, nectar-, and seed-niches provided by the evolution of flowering plants. Most complex are the groups forming the terminal twigs of the phylogenetic tree, and here, especially, much convergence is noted. For example, the various finch sub-groups are found to be more closely related to insectivorous stocks in the same assemblage than to each other. The result is a classification more complex than one based on external characters which would place all finches together. Groups judged to be primitive anatomically all prove to have a worldwide distribution pattern believed to date from Upper Cretaceous time. The original assumption that more advanced groups were restricted in distribution by the separation of faunal regions in more recent periods is confirmed by anatomical relationships. The method seems, therefore, to be valid, and the morphological tree is believed to approximate phylogenetic relationships.
LTERATURE CITED
AMADON, D. 1943. The genera of stalings and their relationships. Amer. Mus.
Nov. no. 1247, pp. 1-16.
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