Fig. 11 in Systematic Review of New Guinea Leptomys (Muridae, Murinae) with Descriptions of Two New Species

Fig. 11. Occlusal views of right maxillary (left pair) and mandibular (right pair) molar rows (X 20) drawn from juvenile examples of Leptomys. Left row in each pair is L. paulus (AMNH 158200), right row in each pair is L. ernstmayri (AMNH 194934). Maxillary rows: cusps are numbered according to Miller's (1912) scheme and referred to in the text with the prefix t; alc, anterolabial cingulum on second molar; pc, posterior cingulum. Mandibular rows: alab, anterolabial cusp; aling, anterolingual cusp; hd, hypoconid; md, metaconid; ed, entoconid; pc, posterior cingulum; pd, protoconid; plc, posterior labial cusplet. The basic pattern of cusps and cusplets seen here is common to all species of Leptomys. Two structures, however, reveal significant variation in their occurrence. Cusp t7 is absent from the second upper molar in our samples of L. paulus and L. arfakensis but generally present in samples of the other species (table 6). A conspicuous anterolabial cingulum (alc) on the second upper molar characterizes specimens of L. ernstmayri from the Huon Peninsula (and variably in samples of that species from elsewhere), but is generally lacking in the other species (table 6).