Thylogale sp.

Piper, Katarzyna J., 2016, The Macropodidae (Marsupialia) of the early Pleistocene Nelson Bay Local Fauna, Victoria, Australia, Memoirs of Museum Victoria 74, pp. 233-253 : 237

Thylogale sp. cf. billardierii ( Desmarest, 1822)

Referred material. NMV P173658, right I1 and partial left I1; NMV P200485, left I1; NMV P200486, right I1; NMV P200487, right I1; NMV P207870, right I1; NMV P187178, left I2 and I3; NMV P200484, left I2; NMV P200483, left I3; NMV P200634, right I3; NMV P216260b, right I3; NMV P173573, left P3; NMV P200415, left P3; NMV P200417, left P3; NMV P200418, left P3; NMV P215784, left M1?; NMV P215779, right M2 and metaloph right M1?; NMV P215872, left M2?; NMV P216889, partial right M2?; NMV P215778, right M3; NMV P200439, right trigonid M3 or M4; NMV P216105, right M 4 in maxilla fragment; NMV P215890, left anterior dentary fragment containing root of i1; NMV P215824, left i1; NMV P215906, root and posterior end of i1; NMV P165469e, left p3; NMV P215791, left p3; NMV P187860, right dp3; NMV P187861, left dp3; NMV P187862, left dp3; NMV P215964, trigonid right dp3; NMV P215804, right m 1–3 in dentary fragment; NMV P200699, left m1?; NMV P200427, hypolophid left m1; NMV P187205, hypolophid left m2; NMV P216884, right m2; NMV P173588, left m3; NMV P200425, hypolophid right m3; NMV P215801, right m3; NMV P215851, worn right m3; NMV P218243, hypolophid right m3; NMV P215860, trigonid left m3; NMV P200642, trigonid left m3 or m4?; NMV P215802, trigonid right m3 or m4; NMV P200426/P200423, left m4?

Remarks. The majority of the material consists of isolated complete and partial molars and upper incisors ( fig. 4 ). The isolated molars are very similar in morphology to Baringa nelsonensis , but can be distinguished based on size, as they are smaller. The lower molars, p3s and upper incisors are virtually indistinguishable from the extant Thylogale billardierii , but are slightly smaller. A small, isolated slightly worn i1 is referred to T. sp. cf. billardierii as it is very similar in size and morphology to T. billardierii , being long and narrow, with narrow dorsal and ventral enamel flanges, a ventrolingual enamel band and a subhorizontal wear facet (length 22.1 mm, maximum depth 6.2 mm) ( fig. 4A ).

The P3 NMV P173573 is worn, so appears to be slightly shorter than the P3 of T. billardierii , but is very similar morphologically. It was previously identified as a dP2 of Baringa nelsonensis ( Flannery and Hann, 1984; Piper and Herrmann, 2006). Some of the upper molars are virtually indistinguishable from those of T. billardierii (e.g. NMV P215779); others are more tentatively referred to T. sp. cf. billardierii .

Overall, these specimens clearly belong to Thylogale and are closest in morphology to extant T. billardierii , but are about 8% smaller. A small specimen of T. billardierii has been reported from Mt Hamilton, Victoria ( Wakefield, 1963). T. billardierii formerly occupied SE South Australia and Victoria, but is now extinct on the mainland, and is restricted to Tasmania and the larger Bass Strait islands ( Strahan, 1995).

Figures

Figure 4. Thylogale sp. cf. T. billardierii: a, NMV P215824, left i1, labial view; b, c, NMV P215804, right partial dentary with m1–3, occlusal and labial views; d, NMV P187860, right dp3, occlusal view; e, NMV P215791, left p3, labial view; f, NMV P200415, left P3, occlusal view; g, NMV P200485, left I1, NMV P187178, left I2–3, labial view; h, NMV P215784, left M1?, occlusal view; i, NMV P215779, right M1–2, occlusal view; j, NMV P215778, right M3, occlusal view; k, NMV P216105, right M4, occlusal view. Scale bars = 5 mm (h–k all to same scale).