Protemnodon 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 : 238

Protemnodon sp. cf. brehus ( Owen, 1874)

Referred material. NMV P201127, crushed left and right dentaries with i1, p3, m1–4; NMV P215985, left dentary fragment with m3–4; NMV P215991, trigonid right m; NMV P215994, tip of right i1; NMV P201153, tip of left i1; NMV P216001, right dp2; NMV P173647, left dp2; NMV P215995, right dP2.

Remarks. The specimens here referred to Protemnodon sp. cf. brehus Owen (1874) are very similar in size and morphology to P. brehus as described by Bartholomai (1973) from the eastern Darling Downs, Queensland ( fig. 5 ). They conform to the revised generic definition of Dawson (2004) with the exception of the lower incisors, which show greater similarities to Silvaroo bila Dawson, 2004 .

P. sp. cf. brehus is less common in the Nelson Bay LF than P. roechus . It is distinguished from P. roechus by the following characters, which are considered here to be enough to warrant the separation of the Nelson Bay material into two large species (see below): 1) the crest of dp2 is more markedly curved lingually at its posterior end; 2) p3 is slightly broader, has three to four well-defined vertical grooves and ridges, and is unconstricted at the posterior one-third; 3) the lower molars are relatively broader; 4) the anterior cingulum is shorter and broader, extending across the entire anterior face of the protolophid; 5) a stronger premetacristid and an anterolingual fossette are present; 6) a well-developed horizontal posterior cingulid and postentocristid are present; 7) m4 is less constricted across the talonid basin.

The lower molars of P. sp. cf. brehus from Nelson Bay differ from P. brehus from other faunas in the size of the m3 and m4, which are both relatively shorter and narrower than most other specimens. The i1s are also smaller, shallower dorsoventrally but wider buccolingually, and are more lanceolate than the i1s of P. anak , P. brehus and P. roechus . In these features the incisors are more similar to smaller Pliocene Protemnodon species e.g. P. snewini ( Bartholomai, 1978) and P. otibandus ( Plane, 1967) , but differ from them in the unusual vertical wear pattern and lack of a ventral enamel flange.

Figures

Figure 5. Protemnodon sp. cf. P. brehus: a–c, NMV P215985, left dentary fragment with m3–4, occlusal, lingual and labial views; d, e, NMV P201127, crushed dentaries, right p3, m1–4, occlusal view, and right and left i1, p3, m1–4, labial and lingual views, respectively; f–h, NMV P173647, left dp2, occlusal, lingual and labial views. Protemnodon sp. upper incisors: i, NMV P173663, right I1, I3, labial view; j, NMV P215990, right I1, labial view; k, NMV P173688, left I2–3, right I3, labial view. Scale bars = 10 mm.