Ancient Jaguars

[Acinonyx sp.]

From Slaughter 1966

Panthera onca augusta (Leidy) 
A large feline is represented by various skull fragments and limb elements in the collection of the Bureau of Economic Geology, University of Texas (BEG-UT 40673-45 to 40673-80). This material differs from pumas and is like the modern jaguar in the following characters: the mastoid is larger, especially in its outward projection; the bulla is less elongate and not ridged anteroposteriorly; the anterointernal process of the entotympanic is flattened; and the fringe of the ectotympanic extends farther forward. The juncture of the bicipital crest and the deltoid ridge is lower on the humerus shaft (about midlength). All of these characters are shared with P. atrox but our material is below the size range for that species; the ulna olecranon in our specimen rises higher above the sigmoid notch and is straighter along its posterior edge. There is one character, however, that does not fit the published data on jaguars; p4 is smaller relative to M1 than in P. atrox and modern jaguars. This difference is not considered important enough to outweigh the many other totally jaguar-like characters, however, and reference to the living species is made with confidence. Simpson (1941), when reviewing the large Pleistocene felines from North America, demonstrated that much of the material is indistinguishable from the living species, P. onca. Like the Laubach Cave specimen and one described by Semkem (1961) from Longhorn Cavern in Texas, most of Simpson's specimens are slightly larger than modern specimens of P. onca milleri, the subspecies currently living closest to the United States, but probably within the size range of P. onca palustrus of South America. Even so, Simpson felt it convenient and justifiable to refer these large jaguars to an extinct race, P. o. augusta (Leidy).

*This image is copyright of its original author

*This image is copyright of its original author

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