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Patterns
of Cranial Variation in Neotropical Cats
Multivariate
Principle Components Analysis was used to analyze the skull shape
and size of eight Neotropical cat species. The eight species can be
divided into three size groups. Leopardus tigrinus (oncilla),
Leopardus colocolo (Pampas’ cat), Leopardus wiedii
(margay), and Oncifelis geoffroyi (Geoffroyi’s cat) form
the smallest group (2.2-5 kg). Leopardus pardalis (ocelot)
and Herpailurus yaguarondi (jaguarundi) fall into a medium
sized group (9-11.5 kg). Panthera onca (jaguar) and Puma
concolor (cougar) compose a large size group (85-100 kg). Six
skull measurements were examined: condylobasal length, relative breath
across canines, maxillary tooth row, zygomatic breath and mandibular
height. In each of the samples, size variation accounted for at least
85% of the variation between individual specimens. In all species
except L. pardalis, most non-size variation was due to the
diameter of the canine. Males tended to have larger canines than females
relative to size. Among the small species, L. tigrinus was
readily differentiated from the other three by both size and shape.
The other three species are remarkably similar in skull size and shape.
L. pardalis and P. yaguarondi are quite different in
both shape and size, probably reflecting trenchant differences in
ecology. Finally, P. concolor and P. onca were found
to be extremely similar in patterns of variation in size and shape
of the skull. There are plans to extend the study to include an examination
of geographic variation and character displacement.
This
research was supported by a grant from the National Science Foundation
Research Experiences for Undergraduates program, Award Number DBI
9820303.
Letter
of Gratitude
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