New Australian Taxa
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KUTJAMARCOOT BREVIROSTRUM Chamberlain et al. 2016
New material— UCR 21930, right M1; UCR 16155, right M1; UCR 16199, left broken M1 metastylar shelf; UCR 16213, left M2; UCR 16258, right broken M2; UCR16129, left M2 talon; UCR 15516, right M2; UCR 22884, left M3; UCR16262, right M3; UCR 21817, right M3; UCR 16173, left M3; UCR 16175, left m3; UCR 16165, right m2 or m3 talonid; UCR 15524, right m2 or m3 talonid; UCMP 99187, left broken M2; UCMP 100284, left M1; UCMP 108062, right M1; SAMUC[KT1] 131, right P3; UCMP 66841, left dentary edentulous; UCMP 107798, right m2; UCMP 100276, right m1; UCMP 66836, left dentary with p1; UCMP 66838, right dentary edentulous; UCMP 66840, right dentary edentulous; UCMP 66839, left dentary with partial p2, p3, partial m1; UCMP 108544, left m1; UCMP 107800, left mx talonid.
Age and Stratigraphy—UCR 21930 is from Mark's Micro Site, RV-8453, West side Lake Kanunka, South Australia, Etadunna Formation, Zone E. All other specimens are from Leaf Locality, RV-7231, Kutjamarpu Local Fauna, Wipajiri Formation.
Remarks— The presence of K. brevirostrum in the Etadunna Formation (UCR 21930) extends the previous age of this taxon from the early/middle Miocene to the late Oligocene. UCMP 108062 was previously identified as a dasyuromorphian (Campbell, 1976).
See Chamberlain et al. 2016.
Chamberlain et al. (2016) described the dentition of K. brevirostrum, but the M2 they described was incomplete. Here we describe a complete lightly worn M2 (UCR 15516), and another worn M2, UCR 16213. We also describe a p1 and a p3.
The M2 is only slightly longer than it is wide. StA is a large cusp connected to the paracone via the almost straight preparacrista. A small anterior cingulum is present lingual to StA. The postparacrista does not meet the premetacrista to form a centrocrista, though in UCR 16213, which is a very worn tooth, these crests do meet as a result of wear. StB and StD are both conical in shape and about as large as one another. Two short crests (remnants of StD1 and StC?) descending the posterior flank of StB and the anterior flank of StD join in the ectoflexus. No crest joins StD to the metastyle, though such crest was present in paratype SAM P50827 from Leaf Locality. The protocone is posterolingual to the paracone. The preprotocrista ends just anterior to the paracone. The postprotocrista is straight and joins to the premetaconulecrista at a 120o angle, level with the ectoflexus. The metaconule is small but distinct, and the postmetaconulecrista ends directly lingual to the metacone.
The p1 is longer than it is wide, with a large centrally positioned main cuspid, and a small posterior cuspid. The two cuspid are connected by a steep crest, almost straight in occlusal view. There is no cuspid anterior to the main cuspid. The roots are longer and wider than the crown, with more of the anterior root exposed above the horizontal ramus than the posterior root.
The p3 is similar in morphology to the p1 except as follows. The tooth is much longer and wider. The main cuspid is taller. The crest is less steep.
Figure 9. Kutjamarcoot brevirostrum., UCMP 66836, left dentary with p1 (A, lingual view; B, occlusal view); UCMP 66839, left dentary with partial p2, p3, partial m1 (C, buccal view; D, lingual view; E, occlusal view); UCMP 108062, right M1 (F, occlusal view; G, lingual view); UCR 21930, left M1 (H, occlusal view; I, lingual view); UCR 15516, right M2 (J, occlusal view; K, lingual view). Scale bars equals 5mm (A-E) and 2mm (F-K).