https://doi.org/10.24199/j.mmv.1982.43.08 8 October 1982 WARENDJA WAKEFIELD1, A NEW GENUS OF WOMBAT (MARSUPIALIA, VOMBATIDAE) FROM PLEISTOCENE SEDIMENTS IN McEACHERNS CAVE, WESTERN VICTORIA 2 By J. H. Hope 1 and H. E. Wilkinson University, 1 Department of Prehistory, Research School o\ Pacific Studies, Australian National Canberra. 2 Geological Survey Office, Department of Minerals and Energy, Bendigo. Abstract Cave, Two mandibles and six isolated teeth recovered from Pleistocene sediments in McEacherns wombat. It combines western Victoria, represent a new genus and species of a morphologically primitive unlused symphysis, unrooted, slightly bilobed molars showing little curvature, with a slender ramus, weak development of the masseteric and pterygoid fossae, a low-set articular condyle, and a broad coro- such as noid process. The associated faunal assemblage includes typical later Pleistocene taxa, Modern taxa, Zvgomaturus triiobus, Sthenurus pilli, S. ef. occidentalis and Thylacoleo carnifex, forest dominated by Rattus fuscipes, Antechinus stuartii and Perameles nasuta, indicate wet sclerophyll conditions. Introduction Systematica diagnoses are not intended to McEacherns Cave lies about 550 m south of The following at each taxonomic level, but the Glenelg River, in the Lower Glenelg Na- be exhaustive to those features which can tional Park, southwestern Victoria. In 1963, A. rather are restricted on the type and referred specimens C. Beauglehole and F. Davies discovered fossil be observed mammal bones in the cave and commenced of Warendja wakefieldi. excavations in the floor sediments. preliminary Superorder MARSUPIALIA Illiger, 1811 in 1964 and 1965 by This work was continued Order DIPROTODONTA Owen, 1866 who carried out ex- the late N. A. Wakefield, Family VOMBATIDAE Burnett, 1830 tensive excavations. In 1967, Wakefield pub- Diagnosis: Distinguished from all other Mar- lished a preliminary report describing the cave the presence of four bilobed, faunal re- supialia by and its sediments, and listing the hyposodont, labially curved and open-rooted mains from the initial excavations in 1963 and molars and open-rooted 11 and P3. 1964. The bulk of the material, only partly sorted, was deposited in the National Museum of Victoria in 1972, after Wakefield's death. In Warendja gen. nov. the 1975, J. H. Hope commenced sorting Type species; Warendja wakefieldi sp. nov. Wakefield Collection, and followed this by Known distribution: Pleistocene, western Vic- further excavations at McEacherns Cave in toria. November-December 1977. In May 1978, the Diagnosis; Distinguished from all other vom- remains of a previously undescribed genus of batids by small, sub-rectangular, minimally wombat were found in the material from the bilobed molars, which show little longitudinal 1964-5 excavation. The specimens have been curvature; smooth, unfused mandibular sym- registered in the palaeontological collection of physis; the combination of a broad ascending National Museum of Victoria. the ramus and well developed coronoid process Terminology and Measurements with poorly-developed masseteric and ptery- goid fossae; and the close approximation of the Mandibular terminology follows Stirton the plane of the mandibular Archer (1978). articular condyle to (1967), and dental morphology permanent cheek teeth tooth row. In this latter system, the Woiwuro and M5. Etymology: In the language of the of vombatids are P3, M2, M3, M4 people of the Melbourne district, warendj Measurements were made with a Mitutoyo dial means wombat (Hercus, 1969). caliper, to 0.1 mm. 109 Memoirs of the National Museum Victoria, No. 43, 1982. 110 J. H. HOPE AND H. E. WILKINSON Warendja wakefieldi sp. nov. Table 1 Plate 3, Figure 2 Measurements (mm) of the mandible of Warendja wakefieldi Holotype: NMV P48980, right mandibular fragment with P 3 , M 2 -5, and alveolus for Ii. P48980 P48982 The articular condyle is present but the upper portion of the coronoid process is broken away. Length of mandible 92.5 est. 100 Referred specimens: NMV P48982, right man- Greatest width of mandible 21.5 21.2 Depth of ramus below mid M 4 20.3 24.2 with -5 and the basal dibular fragment P 3 , M 2 Length of diastema 16.8 16.9 portion of Ii . The articular condyle and part of Length from alveolus of incisor to alveolar margin of 51.2 57.6 the coronoid process are not preserved. NMV posterior M 5 Width of ascending ramus 33.0 P48981, isolated right M 5 . NMV P165428, Condyle — transverse width in 1 3 vertical orientation 12.9 isolated left I . NMV P165429, isolated left P . 4 maximum transverse width 14.1 NMV P165430, isolated left M . NMV maximum length in an- 4 PI 65431, isolated right M . NMV PI 65432, teroposterior direction 7.8 3 Height from ventral border of isolated left M . ascending ramus to sigmoid notch 33.1 Type locality: McEacherns Cave, Lower Glenelg National Park, western Victoria. The concavity beneath the anterior root of the specimens were among material in the National ascending ramus and a convexity beneath M 4 . Museum of Victoria derived from the sediments In both mandibles the symphysis is elliptical in identified as Pleistocene by Wakefield (1967). shape. Its major axis is about 34 mm long in P48980 was collected 21 December 1964, from P48982 (the posterior end is broken in P48980), level 'R\ by N. A. Wakefield. P48982 was col- and in both specimens dips posteriorly at an lected 4-5 September 1964, from a section 24 to angle of 30° with respect to the dorsal edge of 27 feet northwest of the cave entrance, to 1 the horizontal ramus. The length of the minor inch below 'ML\ by N. A. Wakefield. P48981 axis is 9.4 mm in P48980 and 10.8 mm in was collected 22nd May 1964, from level *B2' in P48982. The surface of the symphysis is only a section 18 to 21 feet northwest of the cave en- slightly roughened in both specimens, and there trance, by N. A. Wakefield. P165428-32 were is no indication of symphyseal fusion between collected from level 'Q\ by N. A. Wakefield. left and right mandibles. Diagnosis: That of the genus until other species This condition could be taken as evidence are described. that both mandibles were juvenile, but P48980 Etymology: Named in honour of the late Nor- is certainly fully adult. A fortuitous break be- the full man Arthur Wakefield. tween P 3 and M 2 allowed inspection of length of these teeth, which have almost iden- Description tical top and bottom dimensions. In juvenile Mandible: (Table 1): The mandible is wombats, all teeth are distinctly conical, with remarkably smaller and more delicately built proximal dimensions greater than distal (wear than in all other known vombatids. In P48980 surface). The disparity reduces progressively especially, and to only a slightly lesser degree in until adulthood is reached. P48982 is an older P48982, this is emphasised by the swept-back adult specimen, showing a greater amount of appearance of the ascending ramus, the tooth wear. Therefore the lack of symphyseal anterior border of which is inclined at a lesser fusion is a valid diagnostic character. angle than in any other described species. The The diastema is simple in morphology and lightly built appearance of the mandible is due relatively short. In P48980 the diastemal to the presence of very shallow masseteric and margin is a sharp crest, folded inwards slightly, pterygoid fossae, again a feature not found in above a longitudinal groove on the labial sur- any other wombat species. face of the ramus. P48982 is similar, but is not When viewed laterally, the ventral border of as well preserved. The mental foramen in the mandible forms a very shallow curve with a P48982 is large, and lies below the anterior NEW WOMBAT GENUS II alveolar edge of P3 . In P48980 the mental P48980 it probably did not extend as far as the foramen lies anterior to P3 , below the diastema. most posterior point on the condyle. A second, smaller foramen lies posterior to There is no digastric fossa present on either this, below the posterior half of P-$. mandible. Instead, the lingual surface of the In both mandibles the anterior root of the horizontal ramus forms a smooth convexity, ascending ramus is opposite the posterior lobe with its highest point immediately behind the of Ms. Its anterior border sweeps back in a posterior limit of the symphysis. This bulge is gentle convex curve. Although the top of the caused by the large open root of the lower in- coronoid process is not preserved in either cisor, which in P48982 can be seen through a specimen, it is clear that it, and the ascending break in the bone. ramus, are larger relative to the postero-ventral width of the ramus than in any other wombat. Dentition (Tables 2, 3): The total length of the molar row in the holotype P48980 is 32.5 Angle a as defined in Figure 1 is 56° in mm (occlusal measurement), and the corresponding P48980, and 59° in P48982. The condyle is figure for the referred specimen P48982 is 37.8 preserved only in P48980. It is small and ovoid, These figures are significantly smaller than its transverse width about twice its length mm. for any other wombat currently accepted as a antero-posteriorly. It is set very low, close to valid species. All the teeth are open rooted. As the plane of the tooth row, as indicated by a in Lasiorhinus there is no measurement of 18° for angle b as defined in Vombatus and distinct cemento-enamel junction. The cemen- Figure 1 . The articular surface of the condyle is tum continues over the enamel up the column on the lingual side, approaching the line of the so in most tooth row. of the tooth to the occlusal surface, cases enamel is visible only as a rim at the oc- The masseteric fossa is well-preserved in both clusal surface.