Phylogenetic analysis of syringeal morphology and two osteological characters indicates that the broadbills (Eurylaimidae) are not monophyletic, but consist of four clades with successively closer relationships to the Madagascan asities (Philepittidae). An analysis of these data combined with hindlimb myology characters described by Raikow (1987) yields the same result. The sister group to Philepitta and Neodrepanis is the African broadbill Pseudocalyptomena. The sister group to this clade includes all of the Asian broadbills, except the monophyletic genus Calyptomena. The African genus Smithornis is the sister group to all other broadbills and asities. A biogeographic analysis indicates that the Madagascan endemics share a most-recent biogeographic connection with the central African genus Pseudocalyptomena. Phylogenetic associations between transitions in bill morphology and diet indicate that bill morphologies have evolved both in association with evolution of frugivory and nectarivory, and in apparent response to intrinsic factors within the context of frugivorous and insectivorous diets. A phylogenetic classification of the broadbills and asities is proposed in which all broadbills and asities are placed in five subfamilies of the Eurylaimidae, and the separate family Philepittidae is abandoned. Received 27 January 1992, accepted 23 November 1992.
Museum of Natural History and Department of Systematics and Ecology,
University of Kansas, Lawrence, Kansas 66045, USA
THE BROADBILLS (Eurylaimidae), asities (Phi-
lepittidae), and pittas (Pittidae) form a clade of
Old World suboscine passerines (Sibley et al.
1982, Raikow 1987). They are broadly distrib-
uted in tropical Africa, Madagascar, Asia, and
the Australo-Papuan region. Although they are
much less diverse than the New World subos-
cines, the Old World suboscines include an eco-
logically diverse group of terrestrial and arbo-
real insectivores, frugivores, and nectarivores.
As one of the major basal passerine clades, the
broadbills, asities, and pittas are an interesting
group with which to investigate the biogeo-
graphic history of the Old World tropical avi-
fauna. In particular, the phylogenetic relation-
ships of the asities may provide insight into the
biogeographic history of Madagascar. In this
paper, I present a phylogenetic analysis of the
syringeal morphology of the broadbills (Eury-
laimidae) and asities (Philepittidae), and use this
phylogenetic hypothesis as a comparative
framework in investigations of the biogeo-
graphic history and evolutionary ecology of the
group.
The broadbills include 14 currently recog-
nized biological species in eight genera (Peters
1951, Sibley and Monroe 1990). Six genera are
restricted to southern Asia (Corydon, Eurylaimus,
Cymbirhynchus, Serilophus, Psari$omus, and Calyp-
tomena) and two genera are found in Africa
(Smithornis and Pseudocalyptomena). The asities
include four species in two genera (Philepitta
and Neodrepanis) that are restricted to Mada-
gascar. The 23 to 31 species of pittas are usually
placed in the single genus Pitta (Mayr 1979,
Sibley and Monroe 1990). They range through-
out the Old World tropics, but are most diverse
in southern Asia.
The taxonomic history of the Old World su-
boscines and their position within the passer-
ines has been thoroughly reviewed by Raikow
(1987). Of particular interest here are the Af-
rican and Madagascan genera that were origi-
nally classified as oscines and, subsequently,
were recognized to be suboscines on the basis
of syringeal morphology. Smithornis and Pseu-
docalyptomena were placed in the oscine fly-
catcher family Muscicapidae (Sharpe 1901,
Rothschild 1909). Subsequent anatomical ob-
servations by Bates (1915) and Lowe (1924, 1931)
demonstrated that they were not oscines, but
rather African broadbills. In the 1800s, Philepitta
was associated with the Sturnidae, Paradisaei-
dae, and Nectariniidae, but was confirmed by
Forbes (1880b) to be a suboscine based on sy-
ringeal morphology. Neodrepanis, the Madagas-
can genus of sunbird-asities, was placed in the
oscine family Nectariniidae until Amadon (1951)
made syringeal observations demonstrating that
it was suboscine, and placed it in the Philepit-
tidae.
Although syringeal morphology was impor-
tant in the initial recognition of the Old World
suboscines (Forbes 1880a, b, Bates 1915, Lowe
1924, 1931, K6ditz 1925, Amadon 1951), it has
not been used explicitly to reconstruct the phy-
logenetic interrelationships of these birds. Ames
(1971) described the syringes of a broad sample
of Old World suboscines and recognized that
the asities and some broadbills were quite sim-
ilar in syringeal morphology. However, in the
eclectic spirit of the day, he concluded that these
similarities were primitive but still sufficient to
support placement of the two families taxonom-
ically near to one another.
Sibley et al. (1982) proposed that broadbills
and pittas form a clade that is the sister group
to the New World suboscines based on DNA-
DNA hybridization. However, Sibley et al.
(1982) lacked DNA samples of the asities, and
no molecular hypothesis for their phylogenetic
relationships has been published.
Most recently, Raikow (1987) performed a
thorough phylogenetic analysis of the hind-
limb myology of the Old World suboscines and
produced a well-resolved hypothesis of phy-
logeny for the group using 23 hindlimb myo-
logical and 5 other morphological characters.
Raikow concluded that: the Old World subos-
cines excluding the Acanthisittidae form a clade;
the pitta, broadbill, and asity families are mono-
phyletic; and the asities and broadbills are sister
groups. He also presented the first phylogenetic
hypothesis for the interrelationships of the
broadbills, placing the African genus Pseudo-
calyptomena and the Asian Calyptomena as the
first and second sister groups, respectively, to
the rest of the genera in the family.
Here, ! describe the syringeal morphology of
the broadbills (Eurylaimidae) and asities (Phi-
lepittidae), and present a phylogenetic analysis
of syringeal characters and two osteological
characters. These data are analyzed in combi-
nation with hindlimb myology and other mor-
phological characters described by Raikow
(1987), and then this phylogenetic hypothesis
is used as a historical framework for investi-
gating the biogeography and evolutionary ecol-
ogy of the broadbills and asities.
METHODS
I observed 46 syringeal specimens of 13 species of
broadbills and asities. The sample included all but
five species of broadbills and asities in 9 of 10 genera.
An additional 23 specimens of 10 species of Pitta were
examined for outgroup comparison. The sample in-
cluded 28 specimens that were cleared and double
stained for cartilage and bone (Dingerkus and Uhler
1977, Cannell 1988) by Wesley E. Lanyon. The re-
maining uncleared syringeal specimens were treated
with reversible iodine stain (Bock and Shear 1972) for
resolution of muscle fibers. Complete descriptions of
the syringeal morphology of broadbills and asities,
and list of the specimens examined are presented in
the Appendix. The syringes of Pitta, Smithornis, Ca-
lyptomena, Psarisomus, and Cymbirhynchus are illustrat-
ed in Figure 1, and those of Eurylaimus, Serilophus,
Pseudocalyptomena, Philepitta, and Neodrepanis are
shown in Figure 2. I also examined suboscine skeletal
specimens from the American Museum of Natural
History and the Field Museum of Natural History.
Syringes and skeletons were observed under a Wild
M5A binocular dissecting microscope and illustra-
tions were prepared with a camera lucida.
For the phylogenetic analysis, I accept the mono-
phyly of the clade including broadbills and asities
based on Raikow's (1987) observation of three shared
derived myological characters (original character
numbers from Raikow 1987): (13.1) attenuate M. gas-
trocnemius pars medialis with a concave cranial mar-
gin; (14.1) restricted insertion of M. gastrocnemius;
and (18.1) plantar viniculum present, subsequently
reversed in Neodrepanis. (These three characters are
not included in the analysis to simplify the calcula-
tions.) For outgroup comparison, I accept the mono-
phyly of the Old World suboscine clade--including
the Philepittidae, Eurylaimidae, and Pittidae--with
the New World suboscines (including Furnarioidea
and Tyrannoidea) as their sister group (Feduccia 1974,
1975, 1976, Sibley et al. 1982, Raikow 1987, Sibley and
Ahlquist 1990). The Acanthisittidae are grouped by
some authors with the other Old World suboscines,
but I accept Raikow's (1987) hypothesis that the Acan-
thisittidae are the sister group to the oscine passer-
ines. Variations within the ingroup--the broadbills
and asities--were polarized by outgroup comparison
to the pittas, the New World suboscines, and the os-
cines (Wiley 1981, Maddison et al. 1984). The New
World suboscines and the oscines were not included
in the computer calculations because they were con-
cluded to be primitive for all of the characters ana-
lyzed (see character descriptions).
Syringeal variation was coded as 19 characters.
Complex multistate characters were coded as either
ordered or unordered, depending upon whether the
ingroup variation represented a coherent series of
states. Complex characters were ordered if the de-
rived states implied a hierarchical transition series
A B C
T
A A1
B1 BI
B1
D
E
Fig. 1. Left dorsolateral view of syrinx of: (A) Pitta versicolor (AMNH 4378); (B) Smithornis rufolateralis
(AMNH 2232); (C) Calyptomena viridis (AMNH 7999); (D) Psarisomus dalhousiae (AMNH 2998); and (E) Cymbirhyn-
chus macrorhynchus (DMNH 61267). Scale bars equal 1 mm. Abbreviations: (A1) A1 syringeal supporting
element. (A2) A2 syringeal supporting element. (B1) B! syringeal supporting element. (I) intrinsic fibers of
M. tracheolateralis. (M) medial cartilages. (S) M. sternotrachealis. (T) M. tracheolateralis.
A
B C
E
S
A1
]31
Fig. 2. Left dorsolateral view of syrinx of: (A) Eurylaimus ochromalus (USNM 223462); (B) Serilophus lunatus
(USNM 509480); (C) Pseudocalyptomena graueri (BM 1930.10.19.2). (D) Philepitta castanea (BM 1968.30.46); and
(E) Neodrepanis coruscans (BM 1968.30.112). Scale bars equal 1 mm. Abbreviations listed in Figure 1.
(i.e. one derived state has all the detail of another but
some additional novel detail that appears to be sec-
ondarily derived). For convenience, ordered transi-
tion series were coded as a pair of additive binary
characters (characters 15-16, 18-19), while unordered
multistate characters were coded as alternative de-
rived states of a single multistate character (characters
1, 2, 7). In each character description, the hypothe-
sized derived state and its distribution in the ingroup
is described first, followed by the primitive state and
its distribution in the ingroup and outgroups. In some
cases, additional justifications of character polarity are
TABLE 1. Taxonomic distribution of derived morphological characters used in phylogenetic analyses of
broadbills and asities. Characters 1-19 syringeal and 20-21 osteological. See text for descriptions. Characters
22-36 include informative morphological characters from Raikow (1987); his original numbers indicated.
Codes: (0) primitive state; (1) derived state; (2) alternate derived state; (?) character state unknown.
Character a
Taxon 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Pitta species 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Smithornis species 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Calyptomena viridis 0 0 0 0 0 0 2 1 0 0 0 0 1 0 0 0
C. whiteheadi 0 0 0 0 0 0 2 1 0 0 0 0 1 0 0 0
Eurylaimus steeri 2 2 0 0 0 0 1 0 1 1 1 1 0 0 0 0
E. ochromalus 2 2 0 0 0 0 1 0 1 1 1 1 0 0 0 0
E. javanicus 2 2 0 0 0 0 1 0 1 1 1 1 0 0 0 0
Cymbirhynchus macrorhynchus 2 2 0 0 0 0 1 0 1 1 1 1 0 0 0 0
Serilophus lunatus 2 2 0 0 0 0 1 0 1 1 1 1 0 0 0 0
Psarisomus dalhousiae 2 2 0 0 0 0 1 0 1 1 1 1 0 0 0 0
Pseudocalyptomena graueri 2 2 0 0 1 1 1 0 1 1 0 1 0 0 0 0
Philepitta castanea 2 2 0 1 1 0 1 0 1 1 0 1 0 1 1 0
Philepitta schlegeli 2 2 0 1 1 0 1 0 1 1 0 1 0 1 1 1
Neodrepanis coruscans 2 2 1 1 1 0 1 0 1 1 0 1 0 1 0 0
Characters 23-36 refer to Raikow's (1987) characters 2, 4-7, 11, 12, 15, 17-20, 24-26, respectively.
discussed. Each character has a reference number for
use in figures and the text. The primitive (0), derived
(1), and alternative derived (2) character states are
referred to using a decimal following the character
number.
The character data were analyzed using PAUP
(Phylogenetic Analysis Using Parsimony, version 3.0s;
Swofford 1991).The first analysis included the 19 sy-
ringeal and 2 osteological characters in Table 1. In
the second analysis, these data were combined with
12 hindlimb myological characters and 3 other mor-
phological characters from Raikow (1987) that were
phylogenetically informative within the broadbills
and asities (Table 1). In all analyses, I used the branch-
and-bound of PAUP (which identifies the shortest
phylogenetic trees) on the set with equally weighted
characters and Acctran character optimization.
In the biogeographic analysis, an area cladogram
was produced by substituting the range of each spe-
cies for that species in the hypothesis of phylogeny
(Nelson and Platnick 1981, Wiley 1981). This area
cladogram was used as an initial hypothesis of the
history of geographic fragmentation of a hypotheti-
cal, broadly distributed, undifferentiated ancestral
taxon. Sympatry of any members of a clade indicates
some secondary dispersal or expansion since allopat-
ric speciation.
In the analysis of ecological evolution, the bill mor-
phologies and diets of each taxon were superimposed
on the phylogenetic hypothesis. The most-parsimo-
nious historical scenario for evolutionary transitions
in these traits were identified by coding them as un-
weighted characters in a PAUP analysis. Phylogenetic
association between transitions in morphology and
ecology were examined as evidence that changes may
have been causally related.
CHARACTER ANALYSIS
The syringeal characters are described in the fol-
lowing order: A elements; pessulus; other accessory
cartilages; B elements; and musculature. The two skel-
etal characters are presented last. The distribution of
the states of these 19 characters and the 12 informative
morphological characters from Raikow (1987) is pre-
sented in Table 1.
$YRINGEAL CHARACTERS
(1) A1 elements oblique to sagittal plane.--In Smithor-
nis, A1-2 are moderately oblique to the midsagittal
plane of the syrinx, creating a narrow lateral mem-
brane between A1 and B1. In Eurylaimus, Cymbirhyn-
chus, Serilophus, Psarisomus, Pseudocalyptomena, Phile-
pitta, and Neodrepanis, the A1 elements are acutely
oblique to the midsagittal plane, with the concave
medial surface of the element oriented caudad. The
oblique A1 elements create an extensive lateral tym-
paniform membrane between A1 and B1 in Psarisomus,
Pseudocalyptomena, Philepitta, and Neodrepanis. In Eu-
rylaimus and Cymbirhynchus, the lateral membrane is
less extensive because the first two B elements are
angled craniad. In Serilophus, B1 is expanded laterally,
is arched, and lies adjacent to A1. All A and B elements
are oriented transversely in Calyptomena, Pitta, and
almost all New World suboscines. A similar orienta-
tion is found in the cotingid genera Ampelion, Dolior-
nis, Zaratornis, and Phytotoma, but this morphology is
an independently evolved synapomorphy of this co-
tingid group (Lanyon and Lanyon 1989). The oblique
states of the A1 elements are hypothesized to be de-
rived; the moderately (1.1) and acutely (1.2) oblique
character states differ significantly in form, and are
T^BLE 1. Extended.
Broadbill and Asity Phylogeny
3O9
Character
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
I 0 0 0 0 1 0 I 0 0 0 0 I 0 1 0 2 I I 0
0 I I I I I I 1 0 I 0 0 0 0 I 0 2 I 0 0
0 1 0 I I I I I 0 I 0 0 0 0 1 0 2 I 0 0
0 0 0 I I 0 0 I 0 0 I I 2 0 I 0 2 I I 0
0 0 0 I I 0 0 I 0 0 I I 2 0 I 0 2 I I 0
0 0 0 I I ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
0 0 0 1 1 0 0 1 0 0 1 1 2 0 1 0 2 1 1 0
0 0 0 1 1 0 0 1 0 0 1 1 2 0 1 0 2 1 1 0
0 0 0 1 1 0 0 1 0 0 1 1 2 0 1 0 2 1 1 0
0 0 0 1 1 0 0 0 0 0 1 0 1 0 ! 0 2 0 0 0
0 0 0 1 0 0 0 0 1 0 0 1 0 1 ! 1 1 0 0 1
0 0 0 1 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
0 0 0 1 1 0 0 0 1 0 0 0 0 0 0 0 1 0 0
hypothesized to be alternative unordered derived
states of a single character.
(2) Dorsal ends of A1 widened.--In Smithornis, the
caudodorsal ends of A1 are widened into a prominent,
asymmetrical hammer shape. In Eurylaimus, Cymbi-
rhynchus, Serilophus, Psarisomus, Pseudocalyptomena,
Philepitta, and Neodrepanis, the dorsal ends of A1 are
widened, but into a symmetrical paddle shape. These
shapes are not found in Calyptomena, Pitta, or most
other passerines, and are hypothesized to be derived.
There is no objective criterion for ordering these two
derived states, so the hammer-shaped (2.1) and pad-
dle-shaped (2.2) forms of dorsal widening are coded
as alternative unordered derived states of a single
character.
(3) A1 fused laterally to A2.--In Neodrepanis, the A1
elements are fused dorsolaterally to A2 to form a sin-
gle element. The small forked ventral tip of this com-
bined A1-2 element may be the ventral remnants of
the Als. This morphology is unique in Old World
suboscines and is hypothesized to be derived.
(4) Sides of A2 acutely oblique.--In Philepitta and Neo-
drepanis, the lateral portions of the A2 element are
acutely oblique to the midsagittal plane and fused
ventrally into a prominent V-shape. In Smithornis, Eu-
rylaimus, Serilophus, and Psarisomus, the lateral portions
of A2 are weakly oblique. In Cymbirhynchus and Pseu-
docalyptomena, the caudoventral margin of A2 is wid-
ened caudad and obliquely oriented, but the cranial
margin is nearly transverse. In other eurylamids, Pit-
ta, and other suboscines, A2 and other single A ele-
ments are transversely oriented. The acutely oblique
A2 element found in Philepitta and Neodrepanis is hy-
pothesized to be derived.
(5) A1 elements thin.--In Pseudocalyptomena, Phile-
pitta, and Neodrepanis, the A1 elements are thin and
much narrower than the other A elements. In other
eurylamids and Pitta, the A1 elements are similar in
width to other A elements. The thin A1 elements
found in these three genera are hypothesized to be
derived.
(6) A2-3 fused ventrally.--In Pseudocalyptomena, the
A2-3 elements are ventrally fused. This morphology
is unique in Old World suboscines and is hypothe-
sized to be derived.
(7) Pessulus present.--In Eurylaimus, Cymbirhynchus,
Serilophus, Psarisomus, Pseudocalyptomena, Philepitta, and
Neodrepanis, an ossified pessulus is fused dorsally and
ventrally to A2. In Calyptomena, an ossified pessulus
is present and fused dorsally and ventrally to A4 or
A5. In Smithornis and most Pitta species, there is no
pessulus. A partial pessulus is present and fused ven-
trally to A3 in Pitta sordida and P. brachyura. A pessulus
is absent in the furnarioids and uniformly present in
the tyrannoids, acanthisittids, and oscines (second-
arily lost in swallows, Hirundinidae; Ames 1971, War-
ner 1972). The hornology of the pessulus at these
highest levels within passerines has not been as-
sessed. Any dorsoventrally oriented supporting ele-
ment at the tracheobronchial junction has been called
a pessulus; however, given the variation in shape,
connection, and composition of these structures, there
is little evidence to support their hornology in all
passerine lineages. It is equally parsimonious to hy-
pothesize four independent origins for the pessulus
in passetines or a single origin with three secondary
losses or redevelopments. Here, the pessulus in eu-
rylamids and philepittids is hypothesized to be de-
rived independently from that in other passerines.
Because of the dissimilarity in shape and relative po-
sition, the pessulus present in most eurylamids and
philepittids (7.1) and the pessulus found in Calypto-
mena (7.2) are coded as alternative, unordered derived
character states. These elements differ significantly in
position and shape, and may be evolutionarily in-
dependent.
(8) Medial bronchial cartilage sheet.--In Calyptomena
viridis and C. whiteheadi, there is an accessory cartilag-
inous sheet at the craniomedial surface of the bronchi
connecting the dorsal and ventral ends of the double
A elements and the pessulus. In most specimens, the
caudoventral margins of these cartilaginous sheets
are connected by a transverse membrane. This struc-
ture is unique among Old World suboscines and is
hypothesized to be derived. Similar, independently
derived structures are known in a few piprid and
cotingid genera (Antilophia, Chiroxiphia, Neopelma, Ty-
ranneutes, Lipaugus, and Tityra; Prum 1990, 1992).
(9) B elements ossified.--In Eurylaimus, Cymbirhyn-
chus, Serilophus, Psarisomus, Pseudocalyptomena, Phile-
pitta schlegeli, and Neodrepanis, the two most-cranial B
elements are completely ossified, and ossification is
gradually reduced caudad. In Neodrepanis, only B1-2
are ossified. Ossification of B elements continues until
B3-6 in Eurylaimus and Psarisomus, B7 in Philepitta
schlegeli, and to Bll-12 and beyond in Pseudocalyp-
tomena and Serilophus. In Philepitta castanea, all B ele-
ments are entirely ossified. B elements in all other
Old World suboscines and most New World subos-
cines are completely cartilaginous. The partially or
completely ossified B elements are hypothesized to
be derived.
(10) B1-2 elements straightened.--In Eurylaimus,
Cymbirhynchus, Serilophus, Psarisomus, Pseudocalypto-
mena, Philepitta, and Neodrepanis, the medially incom-
plete B1-2 are not rounded and ringlike, but are
straightened bars. In all other Old World suboscines,
furnarioids, and most tyrannoids, B elements are
rounded and ringlike. The straightened B elements
in these genera are hypothesized to be derived.
(11) B3 elements straightened, dorsally widened, and
elongate.--In Eurylaimus, Cymbirhynchus, Serilophus, and
Psarisomus, the B3 elements are straightened, dorsally
widened, and elongated, so that they extend beyond
the dorsal ends of other B elements. This morphology
is unique among Old World suboscines and is hy-
pothesized to be derived.
(12) A1, B1 and B2 fused ventrally by cartilage.--In
Pseudocalyptomena, Philepitta schlegeli, and Neodrepanis,
the ventral ends of A1, B1 and B2 are fused together
by a small block of cartilage. This fusion is reduced
but present in Philepitta castanea. This morphology is
unique in Old World suboscines and is hypothesized
to be derived.
(13) Ventral ends of B1-3 broadly fused.--In Calyp-
tomena, the ventral ends of B1-3 are broadly fused by
an expanded cartilaginous lattice. This morphology
is distinctly different from the ventral fusion of A1,
B1-2 in Pseudocalyptomena, Philepitta, and Neodrepanis
(12), and is unique in Old World suboscines. This
morphology is hypothesized to be derived.
(14) Insertion of M. tracheolateralis expanded ventral-
ly.--In Neodrepanis, M. tracheolateralis inserts on the
lateral and ventral surfaces of the fused A1-2 element.
In Philepitta, M. tracheolateralis inserts on the entire
length of A1, except for the extreme ventral ends. In
eurylaimids, Old World suboscines, and primitively
in New World suboscines, the insertion of M. trach-
eolateralis is restricted to the lateral and dorsolateral
portions of A1. The ventral expansion of the insertion
of M. tracheolateralis in Neodrepanis and Philepitta is
here hypothesized to be independently derived.
(15-16) M. tracheolateralis ventrally or dorsally unit-
ed.--In Philepitta castanea, M. tracheolateralis expands
ventrally and dorsally from above A20 to cover the
entire trachea except for a small gap on the dorsal
surface. In P. schlegeli, M. tracheolateralis covers the
entire surface of the trachea. In all other Old World
suboscines and furnarioids, and primitively within
tyrannoids, M. tracheolateralis is restricted to the lat-
eral surfaces of the trachea and does not unite dorsally
or ventrally into a single sheet of muscle. The ventral
union (15) and the dorsal union (16) of M. tracheo-
lateralis are hypothesized to be derived in an ordered
transition series, and are coded as a set of additive
binary characters.
(17) M. tracheolateralis inserts on A3-5. In Smithornis,
M. tracheolateralis inserts on the lateral surface of A3,
4, or 5. In all other Old World suboscines, and prim-
itively within New World suboscines, M. tracheola-
teralis inserts on the lateral surfaces of A1. In subos-
cines with intrinsic syringeal muscles, M.
tracheolateralis inserts on some more cranial A ele-
ments often including A3-5, but Smithornis lacks in-
trinsic syringeal muscles. The unique state found in
Smithornis is hypothesized to be derived.
(18-19) M. tracheolateralis or intrinsic muscles insert
on the lateral A1-B1 membrane.--In Calyptomena, M.
tracheolateralis inserts on the lateral surfaces of A5-
7; intrinsic muscles originate just caudal to this in-
sertion and continue caudad to insert themselves on
the lateral membrane between A1-B1. In C. whiteheadi,
M. tracheolateralis itself apparently inserts on the lat-
eral A1-B1 membrane, and intrinsic fibers are lacking
(Ames 1971). The insertion of M. tracheolateralis is
absent in most other suboscines, but is present in the
Neotropical cotingids and has been hypothesized to
be a synapomorphy of the family (Prum 1990). I hy-
pothesize that this insertion is independently derived
in Calyptomena (18). Also, the presence of intrinsic
muscles in C. viridis is unique among Old World sub-
oscines and is hypothesized to be derived as well (19).
SKELETAL CHARACTERS
(20) Spina externa unforked.--In Philepitta and all
broadbills except Smithornis, the spina externa of the
sternum is pointed and bladelike (Olson 1971, pers.
observ.); in Neodrepanis, it is weakly bifid and lacks
any lateral arms. In Smithornis and almost all other
passerine birds, it is strongly forked with extensive
lateral arms (Olson 1971). The pointed, unforked or
weakly bifid condition present in all broadbills and
asities except Smithornis is hypothesized to be derived.
The unforked condition found in some species of
Procnias (Cotingidae) is independently derived.
(21) Two free cervical ribs.--Neodrepanis and all
broadbills except Srnithornis have two free cervical ribs,
resulting in 15 cervical vertebrae. In these taxa, the
first pair of cervical ribs are small, and lack the un-
cinate process and ventral segment. The second pair
of cervical ribs have uncinate processes and, in some
species, a ventral segment, but none articulates with
the sternum. In Neodrepanis, both pairs of cervical ribs
lack uncinate processes and ventral segments. In
Srnithornis, Philepitta castanea, and most other passer-
ines known, there are only a single pair of free ribs
and, correspondingly, only 14 cervical vertebrae (Ol-
son 1971; pers. observ.). The second ribs have ventral
segments that articulate with the sternum. The con-
dition in P. schlegeli is unknown. The loss of the ster-
hal connection of the second pair of ribs and the
consequent increase in the number of cervical ver-
tebrae is hypothesized to be derived.
RESULTS
Phylogeny.--A phylogenetic analysis of the 19
syringeal characters and the two osteological
characters described above yields a single, most-
parsimonious tree of length 25 and a consisten-
cy index of 0.96 with zero-branch-lengths col-
lapsed (Fig. 3). A phylogenetic analysis of these
data combined with 15 informative morpho-
logical characters from Raikow (1987) yields the
same phylogenetic tree with a length of 50 and
consistency index of 0.82 with zero-branch-
lengths collapsed. (An additional tree of the
same length placed Eurylaimus javanicus outside
of the clade including other Eurylaimus species
because myological data were missing for ja-
vanicus.) Optimizations for the evolution of the
syringeal and myological characters on this
phylogeny are shown in Figure 4.
Raikow's (1987) hypothesis for the phyloge-
ny of the broadbills and asities, in which they
are monophyletic sister groups, requires a length
of 59 and a consistency index of 0.69 to explain
the distribution of the characters in both the
syringeal and myological data sets. The revised
hypothesis of phylogeny (Fig. 3) better explains
all the evidence than the previous hypothesis
of the group in which the broadbills and asities
are monophyletic sister groups (Raikow 1987).
The broadbills as currently recognized (Peters
1951, Raikow 1987, Sibley and Monroe 1990)
are not monophyletic. The broadbills appar-
ently consist of four clades with successively
closer phylogenetic relationships to the mono-
phyletic asities. The three species in the mono-
Smithornis
Calyptomena viridis
Calyptomena whiteheadii
-- Eurylaimus /avanicus
Eurylaimus ochrolaemus
Eurylaimus steerii
Cymbirhynchus
Psadsomus
-- Serilophus
--I Pseocalyptomena
L_' Philopitta
Neodrepanis
Fig. 3. Single most-parsimonious phylogenetic
hypothesis for broadbills and asities. Phylogenetic
analysis of 21 characters yielded this hypothesis with
length of 25 and consistency index of 0.96. Phylo-
genetic analysis of these data combined with 15 ad-
ditional morphological characters from Raikow (1987)
yielded the same phylogenetic hypothesis with length
of 50 and consistency index of 0.82. Pitta was the
outgroup. Tree does not include Corydon surnatranus,
which was unavailable for analysis.
phyletic African genus Smithornis are the sister
group to the rest of the broadbills and asities.
The next clade consists of the three species of
Calyptomena. The sister group to Calyptomena in-
cludes the other Asian broadbills, Pseudocalyp-
tomena, and the asities. These Asian genera--
Eurylaimus, Cymbirhynchus, Serilophus, and Psari-
somus--form a clade that is the sister group to
Pseudocalyptomena and the asities. The asities are
monophyletic, as are both Philepitta and Neo-
drepanis.
Among the six species in Eurylaimus, Cymbi-
rhynchus, Serilophus, and Psarisomus, there are five
diagnosable syringeal morphologies. Each spe-
cies is distinct except for the generally similar
Eurylaimus ochromalus and E. javanicus. It was not
possible to polarize variations among these spe-
cies confidently, so their interrelationships could
not be resolved by this analysis. Furthermore,
the monophyly of Eurylaimus remains unsup-
ported by any characters, including obvious
clearly derived plumage traits.
Four species of broadbills and asities could
not be examined in this study because no spec-
imens were available (Wood et al. 1982). Three
of these species--Smithornis sharpei, Calyptomena
hosei, and Neodrepanis hypoxantha--are hypoth-
esized to belong to their respective monophy-
letic genera. Following Raikow (1987), ! hy-
pothesize that Corydon sumatranus is a member
A
Pitta
1.1, 2.2,17
I Smithornis
7.2, 8,13,18 J 1 Calyptomona vin'dis
I L -- Calyptornena whiteheadii
i Eurylaimus javanicus
Eurylairnus ochrolaernus
20, 21 I Eurylaimus steedi
Cymbirhynchus
I I Psarisomus
1.2, 2.1,7.1,9,101 6 Serilophus
I Pseudocalyptomena
5,18 I 15,-2r3L Philepitta castanea
[_ --- Philepitta schlegeli
4, 1 I I 16 Neodrepanis
3
B
Pitta
29.1, 35
I - Srnithornis
23'126 . att ieiSheadii
I Eurylairnus javanicus
I Eurylairnusochrolaernus
28. 29.2. 35 I Eurylairnus $teerii
J l l Cymbirhynchus
Psarisomu$
L{.- 28 Pseudocalyptornena
25 .::7.3343.1.3L6 ', -::"10edPr;ani $
-31
Parsimonious optmzafions for evolution
Fig. 4.
of morphological characters within the proposed
phylogenetic hypothesis for broadbills and asities:
(A) 21 syringeal and skeletal characters used; (B) 15
informative characters from hindlimb myology and
external morphology described by Raikow (1987).
Characters 22 and 27 each presented as a gain and a
loss, but two gains are equally parsimonious.
of the Asian broadbill clade including Eurylai-
mus, Cymbirhynchus, Serilophus, and Psarisomus.
Biogeography.--An area cladogram based on
this hypothesis of phylogeny was produced by
replacing each terminal taxon with its extant
range (Fig. 5). The biogeographic history of the
broadbills and asities has been complex, in-
cluding expansion or dispersal into secondary
sympatry a number of times. An informative
hypothesis of historical area interrelationships
is supported by the clade including all broad-
bills and asities excluding Smithornis and Calyp-
tomena (Fig. 5). This branch of the area clado-
gram provides evidence that a broadly
distributed ancestral lineage was secondarily
isolated into Asian and African/Madagascan
lineages subsequent to the diversification of
Smithornis and Calyptomena. The African and
Madagascan lineages were later isolated from
each other and became Pseudocalyptomena and
the asities. The former clade diversified within
Asia to become Eurylaimus, Cymbirhynchus, Psar-
isomus, Serilophus, and probably Corydon.
The close phylogenetic relationship of the
asities to a restricted endemic from montane
Central Africa, Pseudocalyptomena, implies that
the Madagascan avifauna had a most recent geo-
graphic continguity with Africa and not with
Asia. The earlier branches of the area cladogram
are not strictly informative because of second-
ary sympatry between the African genera and
among the six Asian genera. However, the po-
sition of the widespread African genus Smithor-
nis as the sister group to the rest of the broadbills
and asities implies that there may have been an
earlier, initial geographic isolation of African
and Asian lineages that resulted in the differ-
entiation of Smithornis from the ancestor of all
other genera, and was subsequently obscured
by secondary dispersal into Africa. This bio-
geographic pattern is similar to those supported
by phylogenies of the barbets and toucans (Prum
1988), and the hornbills (Kemp and Crowe 1985).
All of these groups have paraphyletic or poly-
phyletic African assemblages that include the
initial lineage of a diverse multicontinental ra-
diation.
Evolution of bill shape, diet, and nest architec-
ture.--The revised hypothesis of phylogeny
proposed here provides an historical frame-
work for analysis of the ecological and behav-
ioral diversification of the broadbills and asities.
By parsimoniously superimposing transitions
in bill morphology and diet on the hypothesis
of phylogeny, it is possible to identify phylo-
genetic correlations or dislinkages among these
traits and to investigate hypotheses of morpho-
logical and ecological adaptation.
Raikow (1987) coded the broad bill as a de-
rived character state present in Smithornis and
all Asian genera, excluding Calyptomena (char-
acter 25, Table 1), but the variation in bill size
also includes a potentially independent factor,
the wide gape present in Calyptomena, Pseudo-
calyptomena, and Philepitta. The highly decurved
bill in Neodrepanis differs strikingly from all
other genera in the family.
There are two alternative hypotheses for the
evolution of bill shape in the broadbills and
: li".'i.iii:
0 ø e e (c)
Philepitta Other Asian Ca,ptomena
Smithornis Pseudoca/yptomena Neodrepanis Genera
Fig. 5. Range map and area cladogram based on higher level interrelationships among broadbills and
asities. Range of each taxon is shaded with pattern displayed above its name. ' Other asian genera includes
Eurylaimus, Cymbirhynchus, Serilophus, and Psarisomus. Central clade yields informative hypothesis of area
history.
asities. (Bill shape has diversified into a variety
of forms in Eurylaimus, Cymbirhynchus, Psariso-
mus, Serilophus, and Corydon, but these will not
be analyzed here.) In the first, the wide bill and
gape are lypothesized to have evolved in tle
common ancestor of all broadbills and asities,
with subsequent reductions in bill size in Ca-
lyptomena and the Pseudocalyptomena-asity clade
(Fig. 6A). Subsequently, the wide gape is lost
and an elongate decurved bill has evolved in
tle genus Neodrepanis. The alternative hypoth-
esis differs in that the wide gape evolves in the
common ancestor of the group, with subse-
quent evolution of the wide or swollen bill mor-
phology twice independently in Smithornis and
the large clade of Asian broadbills (Fig. 6B).
Although the second hypothesis is numeri-
cally more parsimonious (five character-state
changes instead of six), the first appears more
likely. The wide bill and wide gape were coded
as separate characters in this analysis to permit
the possibility of the independent, convergent
origin of the broad bill. However, it is unlikely
that these two characters are entirely indepen-
dent, and it is improbable that the wide bill and
wide gape would have had independent origins
from one another if they evolved in a single
lineage (Fig. 6A). Rather, the origin of the two
traits in the first hypothesis is more realistically
considered to be a single correlated change in
bill morphology, making the two hypotheses
numerically equivalent. Furthermore, there are
detailed similarities in bill morphology be-
tween Smithornis and tle broad-billed Asian
genera that strongly support the hornology of
these bill morphologies, as proposed by Raikow
A
B
PNa _ Wide Bill Pitta
Ll Wide Bill Lost $mithom,$ di $mithomi$
I I I Calyptomon Wide Gap2 e II Calyptomon
Wide Bill,
Wide Gape Other Asian Genera Other Asian Genera
- Pseudocalyptomena . . Pseudocalyptomena
-
Philepitta Philepitta
Wide BII Lost
Neodrepanis '-H-- Neodrepanis
Wide Gape Lost,
Wide Gape Lost,
Elongate Bill Elongate Bill
G D
o__ pitta o-- Pitta
Insectiv I Frugivory Smithornis Insectiv vory Smithornis
[ Calyptomena Insectivory Calyptomena
Other Asian Genera Frugi I Other Asian Genera
Pseudocalyptomena Pseudocalyptomena
Philepitta -- Philepitta
Frugivory
Neodrepanis Neodrepanis
Nectarivory/ Nectarivory/
Floral Insectivory FIorat Insectivory
Fig. 6. Alternative hypotheses for evolution of (A, B) bill morphology and (C, D) diet in broadbills and
asities. (A) Single, correlated origin of wide bill and wide gape with two subsequent losses of wide bill. (B)
Single origin of wide gape and two subsequent origins of wide bill. In both hypotheses, wide gape lost and
elongate bill evolved in Neodrepanis. (C) Two independent origins of frugivory. (D) One origin for frugivory,
with secondary reversal to insectivory.
(1987). Overall, the first hypothesis is best sup-
ported by the data.
The diet of most broadbills apparently con-
sists largely of insects, spiders, land snails, and
small lizards (Delacour 1947, Chapin 1953, Smy-
thies 1960, All and Ripley 1970, Friedmann and
Williams 1970). In contrast, Calyptomena, Pseu-
docalyptomena, and Philepitta are largely frugiv-
orous, although all are known to take insects
occasionally (Rockefeller and Murphy 1933,
Rand 1936, Delacour 1947, Chapin 1953, Smy-
thies 1960, Friedmann 1970, Wong 1986, Lan-
grand 1990, S. M. Goodman pers. comm.). Neo-
drepanis feeds on insects attracted to flowers
(Langrand 1990), or insects and nectar (Rand
1936, Collar and Stuart 1985, S. M. Goodman
pers. comm.). By outgroup comparison to Pitta,
which is insectivorous and carnivorous (Dela-
cour 1947, Chapin 1953, Smythies 1960, All and
Ripley 1970, Friedmann and Williams 1970), the
insectivorous/carnivorous diet of most broad-
bills is parsimoniously hypothesized to be the
primitive condition within the broadbills and
asities.
Although the data on the diets of broadbills
and asities are limited, the evolutionary tran-
sition in diet from mainly insectivory to fru-
givory probably occurred in one of two differ-
ent, equally parsimonious ways: (i) twice,
independently in the genus Calyptomena and in
the Pseudocalyptomena-asity clade (Fig. 6C); or
(ii) as a single transition to frugivory in the
common ancestor to all genera except Smithornis
followed by a reversal to insectivory in the large
clade of Asian broadbills excluding Calyptomena
(Fig. 6D). Both hypotheses require two evolu-
tionary changes, but the former hypothesis of
two convergent origins for frugivory is more
likely for several reasons. The two alternatives
give us an opportunity to accept or reject a hy-
pothesis of ecological homology between two
frugivorous clades. Although the frugivorous
diets of Calyptomena and the Pseudocalyptomena-
asity clade are both derived from insectivory,
no details about these diets have been docu-
mented to support this hypothesis of ecological
homology with additional detail or special sim-
ilarity. In the absence of such evidence, it is
better to reject the hypothesis of dietary ho-
mology and accept these frugivorous diets as
historically independent. In addition, frugivo-
ry is often accompanied by digestive special-
izations that may be more likely to evolve twice
than to reverse evolutionarily. In either opti-
mization, the nectarivory/floral insectivory of
Neodrepanis evolved in that genus from frugi-
vory and not from insectivory, demonstrating
that frugivory is not evolutionarily completely
constrained.
The best-supported optimizations for the
evolution of diet and bill morphology can be
used to test the hypothesis that bill shape has
adapted to major transitions in the type of diet.
The current hypothesis documents two transi-
tions in diet from insectivory to frugivory and
a single transition from frugivory to floral for-
aging. Both evolutionary reductions in bill size
are exactly correlated with the two transitions
from insectivory to frugivory. Furthermore, the
unique derivations of floral insectivory and the
elongate bill are also exactly correlated. These
correlations between potential natural selection
pressures in the form of novel diets and derived
bill morphologies provide comparative support
for the hypothesis of the adaptive origin of these
morphological novelties.
All of the broadbills and asities build hang-
ing, globular nests with side entrances that are
made of interwoven sticks and vegetation (Rand
1936, Chapin 1953, Smythies 1960, Collar and
Stuart 1985, Langrand 1990). Pittas make domed
nests that usually are placed on the ground or
horizontal branches near the ground. Else-
where in suboscine passerines, woven hanging
nests are found in various lineages, including
the flatbilled tyrannids and the tyrannoid ge-
nus Pachyramphus, but these nests have been
hypothesized to be independently evolved syn-
apormophies of these two groups (Lanyon 1988,
Prum and Lanyon 1989). The hanging or glob-
ular nest architecture of the broadbills and as-
ities is derived, and constitutes an additional,
behavioral synapomorphy of the group. Inter-
estingly, the oscine sunbirds (Nectariniidae) also
build woven, hanging nests (e.g. Rand 1936,
Bannerman 1953). The strong convergent sim-
ilarity between the nests of the sunbirds and
the sunbird-asity (Neodrepanis) may have con-
tributed to the confidence of its original place-
ment in that family.
DISCUSSION
Alternative phylogenies of the broadbills and as-
ities.--The syringeal morphology of many of
the broadbills and asities has been previously
described (Forbes 1880a, b, Bates 1915, Lowe
1924, 1931, Kditz 1925, Amadon 1951, Ames
1971), but it has not been analyzed phyloge-
netically. When Lowe (1931:454) described the
syrinx of Pseudocalyptomena, he recognized
"strangely enough" that it was even more sim-
ilar to Philepitta than to other broadbills; he was
perplexed because he was convinced that "there
is no reason to regard Philepitta as a member of
the Eurylaemid [sic] group of Passeres."
Ames (1971) concluded that the syringeal
morphology of the asities and some broadbills
was very similar but that these similarities were
probably primitive. Using a phylogenetic anal-
ysis to polarize many of the syringeal features
described by Lowe, Ames, and others has yield-
ed a highly consistent, novel hypothesis of phy-
logeny for the group.
Olson (1971) concluded that variation within
broadbills and other passetines in two osteo-
logical characters--(20) unforked spina externa,
and (21) an additional free, cranial rib and cer-
vical vertebra--did not justify the taxonomic
placement of broadbills as a separate suborder
of passetines. However, he did not go on to
identify the more exclusive group of genera
that share these derived osteological features.
With a single reversal, both these skeletal nov-
elties identify Smithornis as the earliest, differ-
entiated lineage within the broadbills and asi-
ties, and are congruent with syringeal characters
in supporting the paraphyly of the broadbills.
A previous, explicit hypothesis of phylogeny
for the broadbills and asities was proposed by
Raikow (1987). Raikow identified three syna-
pomorphies of the broadbills and asities, in-
cluding the presence of the plantar viniculum.
Raikow (1987) commented on the surprising
weakness of the myological support for the
monophyly of broadbills, but he concluded that
two characters with two derived states provided
synapomorphies of the family (original char-
acter numbers 29 and 33 from Raikow 1987).
Although Raikow (1987:9) stated that analyses
of his ordered and unordered data gave the same
results, neither of these characters provides an
unambiguous synapomorphy of the broadbills
in Raikow's hypothesis of phylogeny if they are
treated as unordered.
Thus, within Raikow's (1987) data set, there
is less support for the monophyly of the broad-
bills than he supposed. Furthermore, Raikow
expressed some skeptical concern about non-
myological characters that supported two other
major broadbill clades within his hypothesis of
phylogeny: (34.1) well developed syndactyly;
and (35.1) bill enlarged.
My analysis indicates that the available char-
acters from all morphological systems are most
parsimoniously explained by the revised phy-
logenetic hypothesis proposed here. This result
is related to the extensive internal congruence
between the syringeal data set and Raikow's
(1987) myological characters. The phylogenetic
hypothesis proposed here is identical to the net-
work of interrelationships among broadbills and
asities proposed by Raikow (1987), but rooted
with Smithornis as the sister group to the other
broadbills and asities.
Within this revised phylogenetic hypothesis,
the monophyly of Smithornis, of Calyptomena, of
the clade including all other genera, and of the
asities is well supported by several derived mor-
phological characters. The clade including Eu-
rylaimus, Cymbirhynchus, Psarisomus, and Serilo-
phus is supported by a single syringeal
synapomorphy and a number of myological
novelties. The Pseudocalyptomena-asity clade is
supported by two detailed syringeal characters,
but may be considered less-well supported than
those above. The monophyly of the broadbills
and asities excluding Smithornis is supported by
two osteological synapomorphies, and may re-
quire further corroboration by other data.
Although this phylogenetic hypothesis is only
partially resolved, the optimizations are not af-
fected by this lack of resolution because all of
the taxa in the unresolved clade are identical
for all the characters analyzed. Additional or-
dering of the unordered syringeal characters (1,
2, 7) will yield the same hypothesis of relation-
ships if dorsally, hammer-shaped A elements
are primitive to paddle-shaped ones, but the
relationships of Smithornis and Calyptomena to
the clade including all other genera are equiv-
ocal if the opposite order is hypothesized. How-
ever, there is no objective basis for applying
additional ordering to these traits, and one of
the unordered characters would provide addi-
tional strength to the current hypothesis if it
were ordered (7).
Syringeal evolution.--I examined 13 of the 17
species of broadbills and asities, and described
11 different, diagnosable syringeal morpholo-
gies. In this respect, the broadbills and asities
resemble the syringeally diverse New World
suboscines, and differ strikingly from the os-
cines, which are relatively homogeneous in sy-
ringeal morphology. By comparison, only a few
families of the true oscines are known to have
distinct, diagnosable syringeal morphologies,
even though this clade includes thousands of
species (Ames 1971, 1975, 1987, Warner 1972,
Cutler in Baptista and Trail 1988).
Although the syringes of most broadbills and
asities have been described previously, I made
a number of novel observations. Intrinsic sy-
ringeal muscles have not been described pre-
viously in any Old World suboscine, however,
completely intrinsic muscles were observed in
the syrinx of male and female Calyptomena vir-
idis. These muscles have independent origins
immediately caudal to the insertion of M. trach-
eolateralis fibers and, like the intrinsic syrin-
geal muscles in other passerines, they are clear-
ly the derived caudal ends of M. tracheolateralis.
Intrinsic muscles have originated at least five
times in manakins (Pipridae; Prum 1992), at least
once in the oscines, and probably several more
times in flycatchers (Tyrannidae) and cotingas
(Cotingidae; Prum and Lanyon 1989, Prum
1990). These numerous convergent develop-
ments of syringeal muscular complexity pro-
vide many evolutionarily independent exam-
ples for comparative analysis of the role of these
muscles in syringeal function and in vocal evo-
lution. Medial syringeal cartilages, or internal
cartilages, were observed in Neodrepanis. These
structures are similar to those of the tyrannids
but are evolutionarily independent (Prum 1990).
Another interesting variation in the syringes
of the Old World suboscines is the presence or
absence of a pessulus, which divides the left
and right medial tympaniform membranes into
potentially separate sound sources. Greenewalt
(1968) hypothesized that laterally independent
musculature, innervation, and vibratile mem-
branes are necessary for control of two simul-
taneous syringeal sound sources. Greenewalt's
"two-voice" model predicts that Srnithornis and
most Pitta should lack the independent two-
voice vocal ability because they lack a pessulus
dividing the medial tympaniform membranes,
whereas all of the other broadbills and asities
that have the structural potential should have
the two-voice ability.
Biogeography of Old World tropics and Mada-
gascar.--Phylogenetic analyses of the biogeo-
graphic history of Old World tropical birds are
just beginning (Kemp and Crowe 1985, Cracraft
1986, 1988, Prum 1988, Cristidis et al. 1991).
There are few corroborated hypotheses of phy-
logeny for the numerous radiations of African
and Asian tropical birds. In addition, there are
no corroborated phylogenetic hypotheses for
the relationships of the other Madagascan en-
demic radiations to other Old World tropical
birds (e.g. Mesornithidae, Leptostomatidae,
Brachypteraciidae, Hyposittidae, Vangidae).
This investigation supports a closest biogeo-
graphic relationship between the avifauna of
Madagascar and Africa. The asities are most
closely related to Pseudocalyptomena graueri,
which is restricted in range to two small high-
land regions in eastern Zaire and southwestern
Uganda (Rockefeller and Murphy 1933, Fried-
mann 1970, Collar and Stuart 1985). Although
Madagascar and Africa are relatively close geo-
graphically, the two land masses apparently be-
gan separating between 165 and 130 million
years ago during the Middle Jurassic (Coffin
and Rabinowitz 1987). The Somali Basin that
separates the two land masses was likely the
earliest rift among the extant Gondwanan con-
tinental elements, and had reached near-mod-
ern dimensions by the Jurassic-Cretaceous
boundary (Coffin and Rabinowitz 1987). Al-
though fossil passetines from distinctive mod-
ern oscine genera have been found in late Oli-
gocene-Miocene deposits in Australia (Boles
1991), the age of the separation of Africa and
Madagascar makes a vicariant origin for this
biogeographic pattern extremely unlikely.
However, there are few objective criteria for
ageing these taxa, and this hypothesis cannot
be ruled out entirely. If the asity lineage orig-
inally dispersed to Madagascar, the phyloge-
netic evidence indicates that it was from Africa
by their common ancestor with Pseudocalypto-
mena. Additional phylogenetic studies of other
Madagascan endemic birds should be conduct-
ed to further aid in the reconstruction of the
biogeographic history of the region.
Neither the African nor Asian broadbills are
monophyletic, and the phylogenetic hypothe-
sis supported here indicates that their biogeo-
graphic history has been complex. A simple
overall scenario for their diversification is: (i) a
primary division between undifferentiated
Asian and African broadbills giving rise to
Smithornis in Africa and the common ancestor
of all other genera in Asia; (ii) diversification
of Calyptomena from other populations within
Asia; (iii) subsequent dispersal or expansion into
Africa and Madagascar of the undifferentiated
Asian lineage followed by isolation of these
Asian and Afro-Madagascan lineages; (iv) iso-
lation of Madagascan lineage from African pro-
to-Pseudocalyptomena and subsequent diversifi-
cation of asities in Madagascar; and (v) complex
diversification of the remaining genera in Asia.
Although this hypothesis is not strictly testable,
it is parsimonious, given that secondary expan-
sion or dispersal is necessary to explain their
phylogenetic interrelationship and current dis-
tributions. The lack of phylogenetic resolution
among most Asian broadbills and their second-
ary sympatry also limits further analysis of their
biogeographic history.
Evolution of ecology and behavior.--The broad-
bills and asities exhibit a wide variety of bill
morphologies and diets. A phylogenetic hy-
pothesis for the group provides an historical
perspective on the process of this diversifica-
tion.
Within the broadbills and asities, phyloge-
netic correlation between novel diets and de-
rived bill shapes supports the hypothesis that
bill shape has adapted to ecological natural se-
lection (Fig. 6A, C). There are two independent
phylogenetic associations between the transi-
tion from insectivory to frugivory and the re-
duction in bill size: in Calyptomena; and in the
Pseudocalyptomena-asity clade. In both cases, the
primitive wide gape was retained through the
transition to frugivory. The reduced bill size in
these genera apparently constitutes an adapta-
tion to frugivory, but the wide gape itself can-
not be an adaptation to frugivory in broadbills
because it originated earlier in a lineage with
the primitive insectivorous diet.
In traditional classifications (Peters 1951,
Amadon 1979), the closest relatives to the asities
were insectivores, implying that the morphol-
ogy of Philepitta was itself a derived adaptation
to frugivory. However, this revised phylogeny
of the group supports the origin of frugivory
prior to the differentiation of the asities. The
bill morphology of Philepitta has evolved in ap-
parent response to detailed aspects of frugivory
on Madagascar (e.g. a depauperate flora), rather
than as an adaptation to frugivory itself. Like-
wise, the diversification of bill morphology in
the insectivorous/carnivorous Asian broadbill
genera occurred within the context of a prim-
itive insectivorous/omnivorous diet.
The evolution of the elongate, decurved bill
in Neodrepanis is phylogenetically correlated
with the evolution of nectarivory or floral in-
sectivory found in the genus, and consitutes a
putative adaptation to that diet. The history of
the bill of Neodrepanis is apparently a continuity
of successive reductions in the primitive bill
morphology of the group. The striking and fre-
quently cited convergence in bill shape and
ecology among Neodrepanis, the oscine sun-
birds, and the Hawaiian honeycreepers (Salo-
monsen 1934, 1965, Areadon 1951, Langrand
1990) is even more remarkable given that the
sunbird-asities are essentially broadbills.
PROPOSED CLASSIFICATION
I propose an explicit phylogenetic classifica-
tion of the broadbills and asities. Wiley (1981)
and Raikow (1985) have discussed the advan-
tages of phylogenetic classifications in detail.
In order to reflect the best supported hypothesis
of the evolutionary history of these birds, I pro-
pose placing all genera of broadbills and asities
in a single, monophyletic family. The name Eu-
rylaimidae Lesson, 1831 has priority over Phi-
lepittidae Sharpe, 1870 (W. Bock pets. comm.).
Continued recognition of the Eurylaimidae as
separate from the Philepittidae would require
acceptance of an ahistorical, paraphyletic
group--the broadbills--that can only be char-
acterized arbitrarily by the absence of the de-
rived features that diagnose the monophyletic
asities.
Within the Eurylaimidae, I place all of the
broadbills and asities in five subfamilies. These
subfamilies are arranged by a sequencing con-
vention so that each subfamily is the sister group
to the remaining subfamilies in the sequence
(Raikow 1985). For example, Eurylaiminae is the
sister group to the Pseudocalyptomeninae and
Philepittinae. Among the many options for rec-
ognizing intrafamilial taxa for the broadbills
and asities, I have chosen the present level of
subfamily designations to preserve previously
recognized subfamilies (Calyptomeninae, Eu-
rylaiminae, and Philepittinae) and limit the
number of new taxonomic names.
Family Eurylaimidae
Subfamily Smithornithinae, new, type genus =
Smithornis.
Genus Smithornis
Subfamily Calyptomeninae
Genus Calyptomena
Subfamily Eurylaiminae
Genus Cymbirhynchus, sedis mutabilis
Genus Psarisomus, sedis mutabilis
Genus Serilophus, sedis mutabilis
Genus Eurylaimus, sedis mutabilis
Genus Corydon, incertae sedis
Subfamily Pseudocalyptomeninae, new, type
genus = Pseudocalyptomena
Genus Pseudocalyptomena
Subfamily Philepittinae
Genus Philepitta
Genus Neodrepanis
The classification includes two new subfam-
ilies: Smithornithinae and Pseudocalyptomen-
inae. I chose not to recognize the available sub-
family group name Neodrepanidinae Areadon,
1979 to include Neodrepanis alone, because
placement of the genus itself within the mono-
phyletic Philepittinae communicates efficiently
both its monophyly and its phylogenetic rela-
tionships.
No spirit specimens of the genus Corydon were
available (Wood et al. 1982), so Corydon is in-
cluded in the Eurylaiminae incertae sedis as a
preliminary hypothesis requiring further in-
vestigation. The other genera in the Eurylaimi-
nae are labeled sedis mutablis to indicate that
their interrelationships to one another are not
resolved (Wiley 1981, Raikow 1985).
ACKNOWLEDGMENTS
The research was completed during my tenure as
a Chapman Fellow at the American Museum of Nat-
ural History, and was funded by the Frank M. Chap-
man Memorial Fund. Curators and colleagues of the
various museums permitted me to borrow and study
specimens in their care: G. F. Barrowclough, AMNH;
G. Cowles, BM(NH); G. K. Hess, DMNH; S. M. Lanyon,
FMNH; W. E. Lanyon, AMNH; M. C. McKitrick,
UMMZ; David Willard, FMNH; and R. L. Zusi, USNM.
Amy Lathtop prepared the final illustrations of sy-
ringes, map, and area cladogram with support from
the University of Kansas Museum of Natural History.
Robert Raikow, Mary McKitrick, and Joel Cracraft
provided useful comments on the manuscript. George
Barrowclough, Waiter Bock, and Steve Goodman pro-
vided interesting insights during the research.
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APPENDIX
SYRINGEAL MORPHOLOGY OF THE
OLD WORLD SUBOSCINES
The syringeal terminology used follows Ames (1971)
and Prum (1992). Hornology among syringeal sup-
porting elements was based on special similarities in
shape, relative position to other elements and muscle
insertions, and composition (in decreasing impor-
tance). An alternative, functional terminology based
on relative position to the tracheobronchial junction
(Kin. g 1989) is completely inappropriate for compar-
ative or systematic studies, since evolutionary changes
in the relative position of the tracheobronchial junc-
tion to the supporting elements will produce mistakes
in hornology assignments among elements.
The syrinx of the Old World suboscines is trach-
eobronchial, incorporating specialized tracheal and
bronchial elements. The ringlike supporting syrin-
Meal elements are divided into two classes or series:
A elements, which are the more cranial series in-
cluding tracheal and some bronchial elements; and B
elements, which are the caudal, entirely bronchial
series. Each series is numbered beginning with the
first element in each series near and proceeding away
from the tracheobronchial junction either cranially
(A series) or caudally (B series). These ringlike ele-
ments can be described as: complete or incomplete;
single or double; ossified, partially ossified, or carti-
laginous; and fused or unfused to other elements. In
contrast, Ames (1971) described double, medially in-
complete elements as "divided," and double, com-
plete elements as "double."
In addition, there are accessory syringeal support-
ing elements that are not ringlike. These include the
pessulus (a transverse bar at the tracheobronchial
junction that separates the roedial tympaniform mere-
branes) and various novel cartilaginous structures in
this area. A pessulus is present in all asities and most
broadbills, but is absent in Smithornis and most Pitta.
Other accessory cartilages are found in Calyptomena
and Neodrepanis, and are described below.
The syringeal musculature of the Old World sub-
oscines includes two paired muscles that are found
in all passerine birds: M. tracheolateralis, which orig-
inates on the cranial end of the trachea and the cricoid
cartilages and usually inserts on A1; M. sternotra-
chealis, which originates on medial surface of cranio-
lateral process of the sternum and inserts on lateral
surfaces of trachea. Both muscles are classified here
as extrinsic. In these Old World suboscine genera,
intrinsic syringeal muscles are found only in Calyp-
tomena viridis, and are referred to here simply as lateral
intrinsic muscles. Specialized structures associated
with the medial tympaniform membranes are present
in some species and these are described below.
Specimens examined were from the collections of
the American Museum of Natural History, AMNH;
Delaware Museum of Natural History, DMNH; Brit-
ish Museum (Natural History), BM; Field Museum of
Natural History, FMNI-I; U.S. National Museum of
Natural History, USNM; and University of Michigan
Museum of Zoology, UMMZ. Specimens followed by
an asterisk (*) were cleared and double stained.
Pitta species (Fig. 1A)
Supporting elements.--All A elements ossified. From
A1-2 to A1-4 double and medially incomplete. Sub-
sequent A elements single and complete. In some
species, dorsal ends of double A elements tipped with
cartilage. A5 dorsally cartilaginous in some species,
whereas in a few other species, A4-5 dorsally fused.
No A elements obliquely angled. In most species, a
pessulus absent. In P. sordida and P. brachyura, ossified
pessulus fused ventrally to A3 and dorsally unfused.
All B elements double, medially incomplete, and car-
tilaginous, and none fused, straight, or ossified.
Musculature.--M. tracheolateralis restricted to lat-
eral surfaces of trachea, and inserts on lateral surface
of A1. M. sternotrachealis inserts on lateral surface
of trachea between A8 and All.
Membranes.--No specialized membranous struc-
tures observed.
Specimens examined.--angolensis, AMNH 8262', 8940,
9680; baudi, DMNH 61995, 61998; brachyura, AMNH
2237*; caerulea, BM 1970.27.1'; erythrogaster, AMNH
2236', 4373, uncat. TG-15, uncat. TL-163; granatina,
BM 1906.3.16.11; guajana, AMNH 4034*; iris, AMNH
4530; oatesi, AMNH 2234', 2235*; sordida, AMNI-I
4033', 8259*; soror, BM 1928.6.26.1832'; superba,
AMNH 2239*; versicolor, AMNH 4374, 4376', 4378*.
Smithornis rufolateralis and
S. capensis (Fig. lB)
Supporting elements.--All A elements ossified. A1-2
double and medially incomplete. A1-2 angled oblique
to midsagittal plane at about 45 ø. A1 robust, and its
dorsal end widened caudally in hammer shape and
caudally tipped with cartilage. A1 larger in capensis
than rufolateralis. A2 and subsequent elements nar-
rower. A3 and above single, complete, and unfused.
Large membrane gap on ventral surface of trachea
between oblique A2 elements and normally oriented
A3. No pessulus. All B elements cartilaginous, double,
medially incomplete, and rounded. Small lateral
membrane gap between B1 and A1. Medial tympan-
iform membrane continuous between two bronchi
and connected to dorsal and ventral end of B ele-
ments, A1-2, and dorsocaudal section of A3.
Musculature.--M. tracheolateralis restricted to lat-
eral surface of trachea and inserts on A4 (in 1 capensis
specimen), on A3 on left side and A4 on right (in 2
rufolateralis specimens), or on A5 (in 1 rufolateralis
specimen). M. sternotrachealis thin and inserts di-
rectly on M. tracheolateralis at A5-7, immediately
cranial to insertion of M. tracheolateralis.
Membranes.--No specialized membranous struc-
tures observed.
Specimens observed.--S. rufolateralis, AMNH 2232',
2232A*, uncat. S. capensis, UMMZ RBP4023.
Smithornis sharpei
None available for examination (Wood et al. 1982).
Previous description by Bates (1915) consistent with
these observations of other species of Smithornis.
Calyptomena viridis (Fig. 1C)
Supporting elements.--All A elements ossified and
all B elements cartilaginous. A1-4 double, medially
incomplete, rounded, and normal in orientation. A1
straighter and longer dorsally than other double A
elements, and it juts out dorsally beyond other sup-
porting elements. A1-2 ventrally tipped with carti-
lage. A5 and subsequent elements single, complete
and unfused. (In one specimen, one anomalous half
ring (A4L) on left side fused dorsally and ventrally
to A5.) Series of single A elements increase in di-
ameter craniad (from A8 to 11) and then decrease in
diameter (from A11 to 16), producing prominent bulge
in trachea. Trachea widens from approximately 2.5-
2.8 mm in diameter to 3.8-4.2 mm. (More accurate
measurements not possible because of presence of M.
tracheolateralis.) Flat ossified pessulus fused dorsally
to A5 and ventrally to A4 or A5. All B elements dou-
ble, medially incomplete, and rounded. B1-3 broadly
fused at ventral ends. Dorsomedial surface of each
bronchus composed of sheet of cartilage fused to dor-
sal and ventral ends of A3-4 and to pessulus. This
accessory cartilage sheet forms dorsal margin of me-
dial tympaniform membrane. Lateral membrane be-
tween A1 and B1 narrow and not tympaniform.
Accessory cartilages and membranes.--A large sheet of
cartilage forms cranial margin of lateral tympaniform
membrane and fused to pessulus and to dorsal and
caudal ends of double, medially incomplete A ele-
ments (A1-4).
Musculature.--M. tracheolateralis well developed
and restricted to lateral surfaces of trachea. Muscle
forms prominent belly at tracheal expansion between
A8-15. A few fibers originate on lateral surface of
trachea at cranial margin of drum and join deep fibers
of muscle. M. tracheolateralis splits into dorsal and
ventral bundles at insertion of M. sternotrachealis at
A8-9, and these separate bellies insert on dorso- and
ventrolateral surfaces of trachea at A6-7. An inde-
pendent, intrinsic group of lateral fibers originate on
lateral surface of A5-7 in complex interdigitating pat-
tern with inserting fibers of M. tracheolateralis. These
intrinsic fibers continue caudad to insert on lateral
surface of lateral membrane between A1 and B1. M.
sternotrachealis also robust, and inserts through gap
in M. tracheolateralis onto lateral surface of A7-8 at
caudal margin of tracheal expansion.
Membranes.--Caudoventral margin of accessory
cartilage sheet connected by narrow transverse mem-
brane in most specimens.
Specimens observed.--AMNH 7999*; DMNH 60813,
60971, 61648, 61849, 61997.
Calyptomena whiteheadi
Syrinx of this species not examined, but previously
described by Ames (1971). Syrinx apparently gener-
ally similar to C. viridis. Accessory cartilages present
on medial surface of bronchi. However, Ames (1971)
did not mention any expansion in diameter of trachea.
He did not describe any intrinsic belly in M. trach-
eolateralis. Completely extrinsic M. tracheolateralis
apparently inserts on lateral A1-B1 membrane as in
C. viridis.
Calyptomena hosei
No previous descriptions. No specimens available
for examination (Wood et al. 1982).
Eurylaimus ochromalus, E. javanicus, and
E. steerii (Fig. 2A)
Supporting elements.--Generally, as in Cymbirhyn-
chus except as follows. A1 elements less oblique and
do not meet extensively at ventral ends. A2 also less
expanded ventrally. B1-2 elements less steeply an-
gled than in Cymbirhynchus since AI-2 not as long
ventrally. B elements ossified only to B3-6. In och-
romalus, B1 elements thin and B2 more robust, as in
Cymbirhynchus, but in steerii both B1-2 relatively thin.
In javanicus, both B1-2 relatively robust. Syrinx of
steerii also generally smaller in diameter than Cym-
birhynchus and other Eurylaimus.
Musculature.--Generally as in Cymbirhynchus. M.
sternotrachealis inserts on trachea between A7-11.
Membranes.--No specialized membranous struc-
tures.
Specimens observed.--ochromalus, USNM 223462*,
540477, 540478; steerii, USNM 432343, 510278; javan-
icus, USNM 509475, 509476.
Cymbirhynchus macrorhynchus (Fig. 1E)
Supporting elements.--All A elements ossified and
complete. A1 double, medially incomplete, and acute-
ly oblique to sagittal plane. A1 generally broad,
rounded dorsally, and elongate at ventral end. Cra-
nial margins of these oblique ventral ends meet ex-
tensively on ventral midline. A2 single, complete,
and fused dorsally and ventrally to ossified pessulus.
Dorsal and ventral surfaces of A2 triangular and ex-
panded caudad and closely nested to A1. A3 and above
single, complete, unfused rings. All B elements dou-
ble, medially incomplete, and at least partially ossi-
fied. B1-2 completely ossified, weakly curved, and
slightly oblique to sagittal plane. B1 thin and B2 more
robust. B1-2 closely nested next to one another and
dorsal and ventral ends close to those of A1; also
angled craniocaudally from their dorsal to their ven-
tral ends, producing narrow lateral tympaniform
membranes between A1-B1 and between B2-B3. Ven-
tral ends of A1, B1-2 fused with cartilage. B3 trans-
versely oriented, almost completely straight, and ex-
tends dorsally beyond ends of A1 and other B elements.
B3 ossified for dorsal half, and ossification of subse-
quent B elements gradually reduces to lateral third
by B7. B4 and subsequent B elements transversely
oriented, and successively more rounded.
Musculature.--M. tracheolateralis restricted to lat-
eral surface of trachea. Inserts on lateral and dorso-
lateral surface of A1. M. sternotrachealis robust mus-
cle, and inserts on lateral surface of trachea between
A8-A12. Caudodorsal fibers continuous with M.
tracheolateralis, but cranioventral fibers insert di-
rectly on A elements at ventral margin of M. trach-
eolateralis. M. sternotrachealis constitutes large por-
tion of mass of M. tracheolateralis cranial to its
insertion at A8, and, consequently, M. tracheolateralis
much less massive caudal to A8.
Membranes.--All but one specimen has prominent,
oval fibrous mass in center of medial tympaniforrn
membrane medial to B1 and B2.
Specimens observed.--DMNH 60941, 61226, 61267,
61300.
Serilophus lunatus (Fig. 2B)
Supporting elements.--Generally as in Cymbirhynchus,
except as follows. A1 and A2 not elongated ventrally.
B1 broad laterally, arched, not dorsoventrally angled,
and lies close to A1, eliminating any lateral tympan-
iforra membrane. B2 thinner and lies close to B1 and
B3. Caudal margin of B3 distinctively tapered at its
ventral end. Ossification of B elements continues cau-
dad until at least Bll.
Musculature.--M. tracheolateralis restricted to lat-
eral surfaces of trachea. Inserts by broad sheet of con-
nective tissue on A1 element and A1-B1 lateral mem-
brane. M. sternotrachealis robust and inserts on lateral
surface of A6-9. Serilophus lack fibrous mass on inter-
nal tympaniform membrane.
Membranes.--Small patch of fibrous tissue forms
knobby structure on medial tympaniform membrane.
Caudal end of this structure continuous with broad
strip of connective tissue that extends to interclavi-
cular air sac.
Specimens observed.--USNM 505628, 509479, 509480',
534659.
Psarisomus dalhousiae (Fig. 1D)
Supporting elements.--All A elements completely os-
sifted. A1 double, medially incomplete, and acutely
oblique to mid-sagittal plane. Dorsal ends of A1 wid-
ened, rounded and tipped with cartilage, but element
also broad laterally and ventrally. A2 single, com-
plete, and fused dorsally and ventrally to wide ossi-
fied pessulus. Left and right halves of A2 weakly
angled obliquely. A3 and subsequent elements single,
complete, and unfused. All B elements double and
medially incomplete. B1-2 thin, straight, closely nest-
ed to one another, and ossified except for dorsal ends.
Ventral ends nearly meet ventral ends of A1-2, pro-
ducing extensive lateral tympaniform membrane be-
tween B1 and oblique A1. B3 slightly curved, wider
than B1-2, and ossified except for dorsal eighth and
ventral tip. B4 and subsequent elements broad,
rounded, unfused and ring-like in shape. Ventrolat-
eral halves and quarters of B5 and B6 ossified, re-
spectively. Subsequent B elements cartilaginous.
Musculature.--M. tracheolateralis restricted to lat-
eral surfaces of trachea. Caudal to A8, it gradually
expands dorsad to insert on lateral surface of A2 and
dorsolateral surface of A1. M. sternotrachealis well
developed and inserts on ventrolateral surface of A8-
10, ventral to M. tracheolateralis. Lateral fibers of both
muscles continuous at insertion.
Membranes.--No specialized membranous struc-
tures.
Specimens observed.--AMNH 7998*; USNM 509482-
509484.
Corydon sumatranus
No specimens available for examination (Wood et
al. 1982). Previous description by Miller (1847, 1878)
refers only to absence of intrinsic syringeal muscles
(Ames 1971).
Pseudocalyptomena graueri (Fig. 2C)
Supporting elements.--All A elements ossified. A1
double and narrow, and each side acutely oblique to
mid-sagittal plane of syrinx. Dorsal ends of A1 wid-
ened and fused to pessulus by small cartilaginous
extensions. A2-3 single and dorsally unfused. Ven-
trally, A2-3 completely fused, and combined element
expanded caudally to occupy area between narrow,
acutely oblique ventral ends of A1 elements. Cranial
margins of A2-3 element transversely oriented. A4
and above single and unfused. A wide ossified pes-
sulus fused dorsally and ventrally to A2. All B ele-
ments double, medially incomplete, and partially os-
sifted. B1 elements narrow, almost straight, oblique,
and ossified except for dorsal tips. Bls situated in
center of an extensive lateral tympaniform mem-
brane. B2 elements almost straight, slightly oblique,
and ossified for their ventrolateral third. Ventral ends
of A1 and B1-2 fused with cartilage. All subsequent
B elements rounded, ringlike, transverse, and par-
tially ossified. B3 ossified for about of element, and
ossification reduced gradually to lateral quarter of
element at B12.
Musculature.--M. tracheolateralis restricted to lat-
eral surface of trachea. Muscle splits into dorsolateral
and ventrolateral portions at A7-5, where M. ster-
notrachealis inserts directly on lateral surface of tra-
chea. Muscle reunites at A4-5 into continuous sheet,
and inserts on ventrolateral and lateral surfaces of A1
and dorsolateral surface of A2. M. sternotrachealis
inserts directly on lateral surface of A5-8, passing
through gap in fibers of M. tracheolateralis.
Specimens observed.--AMNH 2233, BM 1930.10.19.2'.
Philepitta castanea (Fig. 2D)
Supporting elements.--All A and B elements com-
pletely ossified. A1 double, medially incomplete, and
each side acutely oblique to mid-sagittal plane. Dorsal
ends of A1 widened but A1 thin laterally and narrow
and pointed at ventral ends. A2 single and complete.
Lateral portions thin, nested closely to A1 elements,
and acutely oblique. Dorsal portion of A2 widened
in triangular shape, but ventrally two thin, oblique
sections of A2 fuse in an acute V-shape. A2 continuous
dorsally and ventrally with narrow, curved pessulus.
A3 and above single, complete and unfused. All B
elements double, medially incomplete, and complete-
ly ossified. B1-2 thin and only slightly curved. B1
narrow and bladelike in shape, and acutely oblique.
Its dorsal and ventral ends nearly touch ends of A1,
but its lateral portion greatly separated from A1 form-
ing large lateral tympaniform membrane. B2 slightly
more rounded than B1, but lies close next to that
element. Ventral ends of A1 and B1-2 weakly fused
by cartilage. B3 and subsequent elements double, un-
fused, transverse, medially incomplete rings. A sec-
ond, smaller lateral tympaniform membrane present
between straightened B2 and round B3.
Musculature.--M. tracheolateralis forms well de-
veloped sheet around trachea from above A20 with
only small gap at dorsal midline. Muscle divides on
ventral midline at A8 and inserts on dorsal margin
of A1 and possibly A2. Insertion extends from oblique
ventral to dorsolateral portions of A1 (illustrated in
Fig. 2D). In some male specimens, insertion extends
dorsally to extreme widened dorsal ends of A1 ele-
ment. In some specimens, fibers on dorsal and ventral
midlines insert on surface of A2. M. sternotrachealis
inserts on lateral midline of trachea on A8-10, and
fibers partially continuous with M. tracheolateralis
fibers after insertion.
Membranes.--Large, tear-drop-shaped piece of fi-
brous tissue present on medial tympaniform mem-
brane between B3 and B5. Dorsal margin broadly
rounded and caudal end narrow and free from mem-
brane. Thin thread of connective tissue extends from
caudal tip of structure and to surface of interclavicular
air sac just lateral to midline of trachea.
Specimens observed.--AMNH 2213, 2228', 2229,
2230*; BM 1968.30.46; FMNH 345696, 345697, 345708-
345710.
Philepitta schlegeli
Supporting elements.--As in P. castanea (Fig. 2D) ex-
cept as follows. Ventral fusion of A1 and B1-2 more
extensive. B1-3 completely ossified as in castanea, but
ossification of subsequent B elements reduced. B4 os-
sifted for its ventrolateral third, and B5 ossified for
ventrolateral quarter. Subsequent B elements com-
pletely cartilaginous.
Musculature.--Apparently as in P. castanea (Fig. 2D),
except as follows. M. tracheolateralis surrounds dor-
sal surface of trachea caudal to A10. Ventrally, it di-
vides on midline into left and right sides at A5 and
inserts as in castanea. Dorsally, it remains in contin-
uous sheet and inserts on dorsal ends of A1 and pos-
sibly on dorsal surface of A2.
Membranes.--Fibrous structure on medial tympan-
iform membrane smaller than in P. castanea. Caudal
end continuous with thin thread of connective tissue
that may connect with interclavicular air sac.
Specimens observed.--BM 1968.30.44'.
Neodrepanis coruscans (Fig. 2E)
Supporting elements.--All A elements completely os-
sifted. A1 double, thin, slightly widened at dorsal
ends, and completely fused to A2 at dorsolateral cor-
ner of that element. A2 single, complete, and broad
and triangular dorsally. Combined A1-2 element
acutely angled oblique along its lateral portions, and
fused ventrally in an acute V-shape. Extreme caudo-
ventral end of combined A1-2 element a finely split
fork, which may be ventral ends of fused Als. A3 and
above single, complete and unfused. Thin, ossified
pessulus fused dorsally to A2 and ventrally to com-
bined A1-2 element. A pair of broad, curved, horn-
shaped medial cartilages connected to dorsal ends of
A1-2 and pessulus, and they extend medioventrally
into medial tympaniform membrane. All B elements
double, transversely oriented and medially incom-
plete. B1-3 nearly straight, closely nested to one an-
other, producing an extensive lateral tympaniform
membrane between A! and B!. B! completely ossi-
fied, and its ventral end dorsally widened. B2 ossified
except for dorsal and ventral eighths. B!-3 fused ven-
trally to A1-2-pessulus complex by square of carti-
lage. B3 and subsequent elements cartilaginous. B4
and below double, medially incomplete, rounded,
ringlike, and unfused.
Musculature.--Cranially, M. tracheolateralis re-
stricted to lateral surface of trachea. At A8, it begins
to expand ventrally and inserts on lateral and ven-
trolateral surfaces of combined A1-2 element. M. ster-
notrachealis narrow and inserts on ventrolateral sur-
face of A11-12, at ventral margin of M. tracheolateralis.
Fibers of M. sternotrachealis continuous with M.
tracheolateralis cranial to their insertion.
Membranes.--No specialized membranous struc-
tures.
Specimens observed.--AMNH 223!*, BM !968.30. ! !2',
FMNH 345711.
Neodrepanis hypoxantha
No previous descriptions. No specimens available
for examination (Wood et al. !982).