Significance of the Scapula for Variation and Attachment of Extrinsic and Intrinsic Musculature within Felids (Mammalia Felidae)


Meeting Abstract

98-5  Saturday, Jan. 6 14:30 – 14:45  Significance of the Scapula for Variation and Attachment of Extrinsic and Intrinsic Musculature within Felids (Mammalia: Felidae) JASINSKI, SE*; CARTER, AM; DODSON, P; University of Pennsylvania; University of Pennsylvania; University of Pennsylvania jasst@sas.upenn.edu

The forelimb morphology of felids (Felidae) correlates with behaviors such as locomotion and prey capture. While the bauplan of felids is conservative, many species differ in the morphology of their scapula. This bone is a pivotal area of attachment for both extrinsic and intrinsic muscles. This may make the scapula an ideal element for predicting locomotor and hunting behaviors of felids. We collected 2D geometric morphometric and measurement data of the scapulae (n=85) of 12 extant genera and 21 species. We tested for differences in scapula morphology by comparing measurement data and using phylogenetically corrected principal components analyses based on a molecular phylogeny. The analyses indicate that semi-arboreal species that exhibit ambush hunting occupy the greatest distribution of morphospace. Some features remain common within the family, such as an enlarged caudal angle for the large m. teres major and enlarged supraglenoid tubercle for a prominent m. biceps brachii. However, the cranial border and the acromion and suprahamate processes show intrafamilial differences. Medium-sized felids show the most variation, and the suprahamate process is the most variable region of the scapula. Some felid clades are highly variable on the medial surface (e.g., Leopardus and Lynx). The medial surface of Acinonyx had the most distinct morphology, separating it from all other species, likely due to its extreme cursorial hunting behavior. Scapular morphology appears to be separating major locomotor groups within Felidae. Many of the differences likely correlate with phylogenetic signal and may indicate these morphologies were established early in the divergence of most major clades. Future inclusion of fossil felids into this dataset should allow for interpretations of possible behavior, biomechanics, and paleobiology.

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