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SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 6.—Vulturidae, probably a new genus and species (MLP 90-X-l-l). Proximal end of ulna and shaft: a,
external view; b, palmar view; c, anconal view. Scale bar=5 cm.
gyps reliquus, and an indeterminate vulturid that probably represents
a new genus and species.
Dryornis pampeanus and Vultur gryphus, from the early?-middle
Pliocene, constitute the earliest record of condors
in South America. The remaining two taxa come from Pleistocene
and middle Pliocene sediments, respectively.
The presence of Geronogyps reliquus (up to now restricted
to the Pleistocene of Peru) in the Pleistocene sediments of the
Pampean region extends considerably the geographic range of
the species. Thus, condors were more widely distributed during
the early?-middle Pliocene and Pleistocene than they are at
present.
Only one condor species now survives in South America,
Vultur gryphus, and its distribution is restricted to Andean regions
and arid steppes of Patagonia. It has been hypothesized
that the decline in condor diversity and the retraction of Vultur
gryphus from the Pampean region is due to climatic changes
and/or to the extinction of megaherbivorous mammals, which
were likely their main food source (as carrion) (Emslie, 1987;
Tonni and Noriega, 1998).