. Bulletin. Natural history; Natuurlijke historie. CO >. o CD CO Deinonychus O o (DOT 1^ ^ Ornitholestes FIG. 83. Suggested phylogeny of the Dromaeosauridae. and Deinonychus may be even more similar than I have illustrated in Figure 82b and f. Only Velociraptor (Fig. 82h) and possibly Chirostenotes (Fig. 82i), among the species^^ represented in that figure, bear comparable resemblances to Deinonychus in the proportions and construction of the manus. Ornitholestes differs from Deinonychus in its long, tapered ischium; long, slender pubis; a long and low anterior process of the ilium; relativ
. Bulletin. Natural history; Natuurlijke historie. CO >. o CD CO Deinonychus O o (DOT 1^ ^ Ornitholestes FIG. 83. Suggested phylogeny of the Dromaeosauridae. and Deinonychus may be even more similar than I have illustrated in Figure 82b and f. Only Velociraptor (Fig. 82h) and possibly Chirostenotes (Fig. 82i), among the species^^ represented in that figure, bear comparable resemblances to Deinonychus in the proportions and construction of the manus. Ornitholestes differs from Deinonychus in its long, tapered ischium; long, slender pubis; a long and low anterior process of the ilium; relatively greater length of dorsal centra; the unusually short mandibular tooth row; enlarged premaxillary teeth; a robust preorbital bar with extensive contact with the maxilla and jugal; the absence of anterior serrations on the teeth; the apparent absence of a surangular foramen and an external mandibular fenestra; and the apparent absence of hyposphene-hypantrum articulations in the dorsal vertebrae. The list undoubtedly could be made longer, but it is sufficiently clear from these that there are major differences between these two taxa. Nevertheless, I consider Ornitholestes as very close, if not actually ancestral, to Deinonychus and later dromaeosaurids. 101 have reconstructed the manus of Compsognathus (Fig. 82c) differently from previous authors (, Huene, 1926, fig. 56) on the bases of a superb cast in the Peabody Museum col- lections, photographs of the original specimen and Nopcsa's interpretation (1930, pi. 18). The usual reconstruction is a tridactyl manus with an unreduced third digit. In my opinion, there is a distinct possibility that the third digit was reduced, perhaps to the extent of a vestigial metacarpal. The third metacarpal of the right manus appears to be a very short, thin, splint- like element. Whereas all the phalanges of I and II are represented, either articulated or slightly removed, there is no evidence of any phalanges of a size appropriate to the
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