Forelimb Myology of Carnivorous Marsupials (Marsupialia: Dasyuridae): Implications for the Ancestral Body Plan of the Australidelphia.

Carnivorous marsupials of the family Dasyuridae represent a more generalized anatomical condition of both craniodental and postcranial features in comparison to other groups of Australidelphian marsupials. Plesiomorphic characters include polyprotodont dentition, didactylous (rather than syndactylous) pedal morphology, the retention of clavicles and epipubic bones, and an unossified patelloid. In light of the anatomy of the postcranial skeleton, we hypothesized that the muscular anatomy of the Dasyuridae would likely display a range of plesiomorphic traits. We performed gross anatomical dissection on the forelimbs of four species of dasyurid marsupials to produce anatomical descriptions and muscle origin and insertion maps for Dasyurus geoffroii, D. hallucatus, and Phascogale tapoatafa, together with comparative notes for Antechinus flavipes. These new descriptions were then compared with those of other marsupials from the published literature in order to establish the principal patterns in forelimb muscular anatomy. In nearly all aspects of anatomy, we found that the arrangement of the muscular origins and insertions, and the relative degree of separation between muscle bellies among dasyurids, provide a natural starting point from which the anatomies of other Australidelphian marsupial groups can be derived. Anat Rec, 300:1589-1608, 2017.