Myology of the head, neck and thoracic region of the lesser grison (Galictis cuja) in comparison with the red panda (Ailurus fulgens) and other carnivorans: phylogenetic and functional implications

MARCOS DARIO ERCOLI; ALICIA ALVAREZ; FELIPE BUSKER; MORALES, MIRIAM MARIANA; EMILY JULIK; HEATHER F. SMITH; BRENT ADRIAN; MIKE BARTON; KEERTHI BHAGAVATULA; MEIFAWN POOLE; MATT SHAHSAVAN; RACHEL WECHSLER; REBECCA E. FISHER

JOURNAL OF MAMMALIAN EVOLUTION

SPRINGER

Lugar: Berlin; Año: 2016 vol. 24 p. 289 - 322

1064-7554

The lesser grison (Galictiscuja) and the red panda (Ailurusfulgens) represent two opposed morpho-functional musteloid extremes. Themid-sized lesser grison is primarily terrestrial, a frequent burrow-dweller, and carnivorous, while the larger, scansorial red pandaeats bamboo. This study documents the axial myology of these species,including muscle descriptions, weights, and optimizations. Muscle maps are alsoprovided for the lesser grison, representing the first axial maps for awild-caught carnivoran. The functional analyses revealed that G. cuja, contrary to A. fulgens, possesses longer, stronger,and subdivided neck muscles. It also possesses a thoraco-lumbar iliocostalissystem that is more developed than the longissimus complex; and numerous, robust,and laterally inserted deep bellies of the cervical and thoracictransversospinalis systems. These adaptations allow powerful neck movementduring hunting and transport of heavy prey as well as axial flexibility,facilitating boundinggaits and lateral movements while navigating subterranean galleries. Some myological traits of the red panda differfrom those expected in a highly herbivorous taxon (e.g., m. sternocephalicus,m. masseter),and may reflect its depredatory ancestry. The optimizationanalysis revealed phylogenetically informative traits across Carnivora,including the absence of m. longissimus capitis in Mephitidae, the absence ofspinous thoracic origins for m. biventer cervicis in Musteloidea, and thepresence of a relatively lateral insertion of m. rectus dorsalis capitisintermedius in the clade Ictonychinae+Lutrinae+Mustelinae. This study revealskey associations between axial myological and osteological adaptations thatwill prove useful for future studies of carnivorans.