A new fossil kangaroo from the Oligocene-Miocene Etadunna Formation of Ngama Quarry, Lake Palankarinna, South Australia

Abstract

Mandibular and postcranial remains attributable to a new fossil kangaroo (Macropodoidea) are described from the Oligocene-Miocene Etadunna Formation deposits of Ngama Quarry at Lake Palankarinna in north-eastern South Australia. The taxon is uniquely differentiated by its straight bunolophodont molar row, elongate P3 with distinct labial/lingual cingulids and 12–13 fine (shallowly incised) cuspids/transcristids, molars with a rectangular (length at least 0.3 > width) occlusal outline, hypolophid formed by a buccally directed crest from the entoconid, absence of a discrete M1 protostylid, transversely broad trigonid basin on the M1, M4 not markedly smaller than the anterior molars, distal end of humerus with sub-equally sized capitellum and trochlea (the latter also closely abutting the entepicondyle), and ulna with distinctly sinuous ventral edge. Relationships of the Ngama Quarry kangaroo are poorly resolved because of missing data; however, inclusion within the most comprehensive published phylogenetic dataset of Macropodoidea suggests close affinity with the currently extant potoroine/macropodid lineage.