Comparing Cats: A Discussion of Similarities & Differences

[LandSeaLion]

Dominusforti is correct. Here is the relevant section from the paper:

Quote:Unfortunately, the scarcity of clavicles in mod- ern felid collections precluded adequate known sex distributions, and therefore, sexual dimorphism could not be excluded as a possible explanation for the dimorphism exhibited in the fossil clavicle sample. Although it would have been particularly interesting to compare the two fossil morphs to sexual dimorphism in tigers and lions, none of the museums have clavicular specimens assigned to male tigers, and only one of the lion specimens was recorded as a female. This leaves the possibil- ity that the size difference seen between the mod- ern lions and tigers and in the two fossil morphs (Fig. 1 and Table 2) is the result of sexual dimor- phism. However, the single female lion in our com- parative sample has among the largest clavicles, and the differences between the clavicles of the two large modern pantherines and the two fossil morphs seems to far exceed the levels of sexual dimorphism exhibited in other skeletal elements of modern felids. The clavicles of male and female cheetah and pumas (n ratios of 1:3 and 5:6, respec- tively) do not appear to exhibit very high levels of sexual dimorphism—for only three of the seven measurements are the male cheetah clavicles larger those of the females (and only a maximum of 27% larger: acromial end thickness), and male pumas are on average larger than female pumas for only five of the seven measures (and only 37% larger for total length). Whereas the larger morph of fossil clavicles are at least 89% (for acromial end AP thickness) and up to 240% (for sternal end thickness) larger than the small morph in all seven measures. Furthermore, the qualitative dif- ferences between the large and small morphs of the Rancho La Brea specimens exceed those found within any of the modern felid species. In other words, the large Rancho La Brea specimens look very much like the clavicles of modern panther- ines, whereas the small Rancho La Brea morph looks very different than any modern felid. There- fore, evidence suggests that the dimorphism in the Rancho La Brea felid clavicle morphology exhib- ited is not sexual but taxonomic.

Reply