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.

Revision of basal macropodids from the Riversleigh World Heritage Area with descriptions of new material of Ganguroo bilamina Cooke, 1997 and a new species

“…Ganguroo bilamina, G. bites, Bulungamaya delicata and Wabularoo naughtoni were recovered as a clade containing potoroines and macropodines+sthenurines, but the relationship was not resolved. Kear et al (2007) and Kear and Pledge (2008) recovered 'bulungamayines' as a paraphyletic group, more closely related to macropodines than potoroines, but with no support (bootstrap values = <50%). They recommended 'Bulungamayinae' to be treated as incertae sedis.…”

“…One specimen of G. bilamina in the fossil collections of the University of California at Berkeley (UCMP) was recovered from the Wipajiri Formation at the Leaf Locality, Lake Ngapakaldi, South Australia. Other specimens from the Etadunna Formation of South Australia in the collections of the South Australian Museum (SAM P) used in metric analyses represent Ngamaroo archeri (Kear and Pledge, 2008) and Purtia mosaicus (Case, 1984). Specimens of the modern Redlegged Pademelon (Thylogale stigmatica) and Red-necked Pademelon (Thylogale thetis) were examined from the Queensland Museum mammal collection (QM J or JM).…”

“…We assessed the phylogenetic relationships of basal macropodid species to other macropodoids using the matrix of Kear and Pledge (2008). While the matrix of Prideaux and Warburton (2010) is more recent, they acknowledged that their principle purpose was to investigate the relationship of bilophodont macropodids, and therefore not suitable to analyse more basal forms.…”

“…They mentioned that their matrix would require an extensive increase in characters and additional outgroups before it could be used for that purpose. Hence why we used the matrix of Kear and Pledge (2008), because it was explicitly generated for assessing the relationship of basal macropodiforms. Their matrix contained 108 qualitative morphological characters including cranial, dental and postcranial features.…”

“…Additional material referable to B. delicata was reported from a number of Riversleigh local faunas (LFs) in Faunal Zones B and C (Cooke, 1997b;Archer et al, 2006). Some of these specimens have been used in phylogenetic analyses (Kear and Cooke, 2001;Kear et al, 2001a;Kear et al, 2007;Kear and Pledge, 2008). However, none of these specimens have been described.…”