Pleistocene extinctions and the perceived morphofunctional structure of the neotropical felid ensemble

MORALES, MM; NORBERTO P. GIANNINI

JOURNAL OF MAMMALIAN EVOLUTION

SPRINGER

Año: 2013 p. 1 - 11

1064-7554

The felid Neotropical ensemble has experienced important changes from the Pleistocene to the present, the extinction of sabertooth cats being the most significant. Assuming that the morphofunctional structure of the Neotropical felid ensemble was maximally expressed when machairodontines were present, we added specimens of Smilodon fatalis and S. populator to a morphological dataset inclusive of all extant species of  Neotropical felids to explore the hypothetical effect of extinction of machairodontines on the perceived morphofunctional structure of the ensemble. We studied 321 specimens of 12 extant species of Neotropical felids plus S. populator and S. fatalis by measuring 123 skulland postcranial morphofunctional variables. We used Principal Component Analysis to find morphofunctional patterns of the skull, postcranium, and both combined (with and without correction for size) of both ensembles, past (with Smilodon) and present (with Smilodon lost to extinction). Canonical Phylogenetic Ordination was performed to assess the degree of phylogenetic influence on this morphospace. We also explored the effect of including homotherines in the Pleistocene guild by including specimens of North American Homotherium serum . Size was the principal factor structuring ensembles. Important morphological characters were associ- ated to ecological performance of species. A pattern of bodily proportions was apparent: morestout species with larger skull, longer rostrum, stronger bite force, and longer pectoral crests, versus gracile, jumping species with opposing characters. The felid morphospace shrankafter the extinction of Smilodon and Homotherium , but the configuration of the portion of space containing extant felids remained stable. This pattern is asso-ciated with deep phylogenetic roots.