.--The presence of an aftershaft in
the Jacamars (Galbulidae) and its alleged absence in the closely-related Puff-birds
(Bucconidae) has long been used as an important character separating these two
piciform families. The supposed absence of the structure in puff-birds apparently
originated with the statement by Nitzsch (1840:94-95) who examined the species known
today (Peters, 1948) as Bucco tamatia, B. capensis, Nystalus chacuru and Malacoptila
]usca. Forbes' diagnosis of the family in the monograph by Sclater (1882) also indi-
cated the aftershaft as absent. In subsequent publications Selater (1891; 1909) used
the same diagnosis. Ridgway (1914:371), apparently following Sclater, used "contour
feathers without aftershafts" as a character separating the puff-birds from the jacamars.
Beddard (1898:189) recorded that in the puff-bird Malacoptila ]usca "the aftershaft
is absent." Beddard's statement is probably the source of Stresemann's (1927-1934:839)
notation that Malacoptila is without an aftershaft. Stresemann's statement is so worded
as to imply that this is the only genus of jacamars and puff-birds entirely lacking
an aftershaft.
In an attempt to resolve the seemingly differing opinions as to the occurrence of
the aftershaft in the Bucconidae, ventral contour feathers from several species of puff-
birds have been examined. Several members of the Galbulidae have been studied for
comparison.
In all of the jacamars examined the aftershaft is present and originates as a single
shaft from the proximal margin of the superior umbilicus. This single shaft subdivides
to form a tuft of approximately 15 (12 to 17 counted) barbs. The barbules lack
hamuli and this downy tuft constitutes the vane of the aftershaft. The junction of
the hyporhachis with the rhachis of the main feather is discrete and well separated
from the proximal barbs of the vane of the main feather.
In the puff-birds the condition of the aftershaft is somewhat different. Instead of
arising from a single shaft there is a group of barbs, each arising separately from the
proximal margin of the superior umbilicus. That these barbs are homologous to the
well-formed aftershaft of the jacamars is indicated by their position, their number
(approximately 12) and their direction, namely, parallel to the rhachis of the main
feather, not lateral to it as with the barbs of the vane. There is not, however, a
September 1956 GENERAL NOTES 253
Vol. 68, No. 3
sharp break between the lateral barbs and those forming the aftershaft group. The
most proximal lateral barbs originate progressively toward the ventral midline of the
feather and thus gradually come into alignment with the aftershaft group. It may have
been this situation which led Forbes to the conclusion that no aftershaft was present.
A point of difference between the aftershaft barbs and the lateral vane barbs lies
in the structure of the axis or shafts of these barbs. The shafts of the aftershaft group
are fine, round filaments; those of the lateral barbs are relatively broad and flat.
Additional evidence that this group of barbs is homologous to a true aftershaft is
found in the studies of Lillie and Juhn (1937) on the origin of the aftershaft. Their
observations indicate that barbs arising in the center of the "ventral triangle," and
having a vertical arrangement, are properly considered homologous with the aftershaft.
If, in view of this evidence, the aftershaft in the Galbulidae is regarded as homologous
to the group of barbs described above in the Bucconidae, the latter group should be
diagnosed as possessing an aftershaft. The marked and consistent differences in
aftershaft structure however, still provide a mutually exclusive pair of diagnostic
family characters.
The species examined were as follows: Galbulidae: Galbalcyrhynchus leucotis, Brachy-
galba lugubris, Jacarrralcyon tridactyla, Galbula alblrostris, Galbula galbula, Galbula
tombacea, Galbula ru/icauda, Galbula leucogastra, Galbula dea and Jacamerops aurea.
Bucconidae: Notharcus rrcrorhynchos, Notharcus pectoralis, Notharcus tectus, Bucco
rrcrodactylus, Bucco tarrtia, Bucco capensis, Hypnelus rujicollis, Malacoptila striata,
Malacoptila panamensis, Malacoptila mystacalis, Monasa atra and Chelidoptera tenebrosa.
All specimens were examined with a 20X binocular microscope.
LITERATURE CITED
BEDDARD, 1 .
1898 The structure and classification of birds. Longroans, Green, and Co., London.
LILLIE, F. R. AND M. JUHN
1937 The origin of the after-feather in fowl: a process of twinning. Science,
86:38-39.
NITZSCH, C. L.
1840 System der pterylographie. English translation by P. L. Sclater, 1867. Ray
Society, London.
PETERS, J. L.
1948 Check-list of birds of the world. Vol. 6. Harvard Univ. Press, Cambridge.
RIm;WAY, R.
1914 The birds of nort.h and middle America. Part 6. U.S. Nat. Mus. Bull., 50.
SCLATER, P. L.
1882 A monograph of the jacamars and puff-birds, or families Galbulidae and
Bucconidae. Porter, London.
1891 Catalogue of the birds in the British Museum. Volume 19. British Museum,
London.
1909 Fam. Galbulidae. In, Wytsman, Genera Avium. V. Verteneuil and L.
Desmet, Brussels.
STRESEMANN, E.
1927-1934 Aves. In, Kukenthal and Krumbach, Handbuch der Zoologie, vol. 7.
Walter de Gruyter and Co., Berlin and Leipzig.
CHARLES G. SIBLEY, Department o! Conservation, Cornell University, Ithaca, New York,
March 6, 1956.