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NUMBER 89 213
AM AL AM AL AM AL AM AM AL AM
FIGURE 3.—Comparison of coracoid of Apodiformes: A, Aegialomis gallicus; B, Hemiprocne mystacea;
C, Argornis caucasicus, new genus, new species; D, Jungornis tesselatus; E, Palescyvus escampensis;
F, Apus apus; G, Archilochus colubris. AM=angulus medialis, AL=angulus lateralis. Arrows indicate
proc. lateralis. Left side, dorsal view, standardized for comparison. (Scale-1 mm.)
lis is not pronounced. The sulcus of M. humerotricipitis is wide
and shallow.
Ulna: The shaft is slender and straight. Both ends are relatively
narrow. The olecranon is tapered, with a narrow base.
The cotyla ventralis is shallow. The ridge separating the cotyla
dorsalis and cotyla ventralis is low and smooth. The tuberculum
bicipitale is located close to the distal border of the cotyla
ventralis. There is a deep fossa for M. ulnometacarpalis ventralis
on the caudoventral side of the proximal end.
Radius: The shaft is thin and slightly bowed craniad. Both
ends are relatively narrow. The tuberculum bicipitale adjoins
the ventral border of the cotyla humeralis.
Carpi ulnare: The proximal margin of the corpus is noticeably
beveled, so that the proximal border of the facies articularis
ulnaris lies much more distally than the base of the proc.
muscularis.
Carpometacarpus: The metacarpale majus is slender,
slightly bowed craniad, and beveled ventrocaudally. The protuberantia
metacarpalis projects dorsally, is proximodistally
elongated, and is placed somewhat distad to the middle of the
craniodorsal surface of the major metacarpal. A well-developed
sulcus tendinosus begins just proximocaudally of the protuberantia
metacarpalis and passes distad and somewhat
caudad, where it widens into a clearly outlined and relatively
deep depression on the dorsal side of the distal end of the major
metacarpal. There is a pronounced tuberculum of M. extensor
metacarpi ulnaris on the caudal margin of the major metacarpal
just opposite the distal border of the proximal symphysis. The
cranial margin of the labrum dorsale of the trochlea carpalis
bears the impression of M. ulnometacarpalis ventralis. The
caudal margin of the facies articularis digitalis major is deeply
concave. The distal part of metacarpale minus is absent in the
holotype; however, the facies articulares metacarpales of the
proximal phalanx of the major digit and of the minor digit are
on the same level in the holotype, which suggests that corresponding
facies articulares digitales major and minor also
should be level relative to the long axis of the carpometacarpus.
Ossa digorum manus: The phalanx digiti alulae is damaged
too badly to recognize any structural peculiarities.
Two large oval fenestrae of the phalanx proximalis digiti majoris
are separated by a dorsally pronounced, obliquely oriented
pila transversa. There is a well-developed proc. distalis on the
caudal margin. The caudal edge of the facies articularis metacarpalis
forms a deep middle concavity.
The phalanx distalis digiti majoris has a caudally enlarged
proximal articulation and a caudally widened tip.
The phalanx digiti minoris is narrow and tapering. It curves
along the caudal margin of the proximal phalanx of the major
digit and extends to the level of the distal margin of the proximal
fenestra. The facies articularis metacarpalis of phalanx digiti
minoris is placed relative to the long axis of the manus on
the same level as the metacarpal facet of the proximal phalanx
of the major digit.
Forelimb Muscles: Tendencies of Transformation
Among the living Apodiformes, the most generalized configuration
of the forelimb muscles is found in the Hemiprocnidae.
The completeness of their set of forelimb muscles reveals a relatively
low level of specialization. Many of their muscles demonstrate
a comparatively simple inner structure. In particular,
unlike the true swifts and hummingbirds, the crested swifts