Paws and Claws: Ecomorphological Differences of Felid Unguals
Mentor 1
Christopher Noto
Location
Union Wisconsin Room
Start Date
24-4-2015 2:30 PM
End Date
24-4-2015 3:45 PM
Description
All living cats are members of the family Felidae. Felids have evolved a range of adaptations to their mainly carnivorous lifestyle including retractable unguals (claws). While felids are similar in overall anatomy, each species possess specialized morphology according to prey preference, predatory methods, habitat, and locomotion. Compared to studies of limb and skull anatomy, little is known about the range of ungual morphology present in extant felids. The purpose of this study is to quantify differences in ungual shape and test their relationship to selected ecological variables. A geometric morphometric analysis was performed on over 180 individual claws spanning 18 extant felid species from the Field Museum of Natural History (Chicago) and the American Museum of Natural History (New York). A series of 14 coplanar landmarks were placed on photos of claws in lateral view using the software tpsDig. Shape data were analyzed with MorphoJ. Results of principal components analysis (PCA) show that the majority of variation between species is explained by changes in the bony portion of the ungual with respect to the length and degree of curvature of the keratinous sheath. Canonical variates analysis (CVA) found that large and small prey specialists’ unguals are significantly different in shape. Furthermore, morphological differences are strongly influenced by whether or not species lived in an open or closed habitat. A linear regression showed a significant positive relationship between body size and prey preference, where a change in claw shape corresponds to body size over 22kg, confirming that prey preference is dependent on body size. These results also confirm the uniqueness of the cheetah claw, which is unlike any other felid. The margay is also an outlier, possibly due to its arboreal lifestyle. Studies like this provide an opportunity to identify ecomorphological traits common to other extant tetrapod unguals, while creating a basis for determining ecological traits of extinct felids and other fossil carnivores.
Paws and Claws: Ecomorphological Differences of Felid Unguals
Union Wisconsin Room
All living cats are members of the family Felidae. Felids have evolved a range of adaptations to their mainly carnivorous lifestyle including retractable unguals (claws). While felids are similar in overall anatomy, each species possess specialized morphology according to prey preference, predatory methods, habitat, and locomotion. Compared to studies of limb and skull anatomy, little is known about the range of ungual morphology present in extant felids. The purpose of this study is to quantify differences in ungual shape and test their relationship to selected ecological variables. A geometric morphometric analysis was performed on over 180 individual claws spanning 18 extant felid species from the Field Museum of Natural History (Chicago) and the American Museum of Natural History (New York). A series of 14 coplanar landmarks were placed on photos of claws in lateral view using the software tpsDig. Shape data were analyzed with MorphoJ. Results of principal components analysis (PCA) show that the majority of variation between species is explained by changes in the bony portion of the ungual with respect to the length and degree of curvature of the keratinous sheath. Canonical variates analysis (CVA) found that large and small prey specialists’ unguals are significantly different in shape. Furthermore, morphological differences are strongly influenced by whether or not species lived in an open or closed habitat. A linear regression showed a significant positive relationship between body size and prey preference, where a change in claw shape corresponds to body size over 22kg, confirming that prey preference is dependent on body size. These results also confirm the uniqueness of the cheetah claw, which is unlike any other felid. The margay is also an outlier, possibly due to its arboreal lifestyle. Studies like this provide an opportunity to identify ecomorphological traits common to other extant tetrapod unguals, while creating a basis for determining ecological traits of extinct felids and other fossil carnivores.
