On the identity of ‘Kolopsis’ watutense (Anderson, 1937) (Diprotodontidae, Marsupialia) and the New Guinean diprotodontid radiation

Abstract

Mackness, B.S., On the identity of ‘Kolopsis’ watutense (Anderson, 1937) and the New Guinean diprotodontid radiation. Alcheringa, 1–10. ISSN 0311-5518.

The New Guinean diprotodontid ‘Kolopsis’ watutense (Anderson, 1937) is shown to be a diprotodontine based on the position of cristids and lower molar morphology. Examination of all known diprotodontine taxa has demonstrated that its original assignment to Nototherium is the most parsimonious and is, therefore, re-instated. However, the synonymy of the enigmatic Zygomaturus nimborensis and Nototherium watutense is re-affirmed. The reassignment of N. watutense to the Diprotodontinae and recognition of the late Miocene Pyramios alcootense as its closest relative is significant as it directly challenges the orthodoxy that the entire New Guinean diprotodontid radiation occurred solely within Zygomaturinae and suggests that the current understanding of New Guinea palaeozoogeography is probably more complex than first assumed. The recognition of N. watutense in the Pliocene Awe Local Fauna is also significant in the Australian context as Nototherium is currently only recognized from Pleistocene deposits suggesting perhaps a greater temporal span for the genus or that further intermediate forms remain to be discovered.

新几内亚的‘Kolopsis’watutense (Anderson, 1937)被归为双门齿有袋类, 根据的是齿脊的位置和下臼齿形态。对所有已知双门齿有袋类分类群的研究发现, 原先将它归为Nototherium是很粗略的做法, 所以对此进行了修正。然而, Zygomaturus nimborensis和Nototherium watutense是同义名这一点得到了再肯定。将N. watutense重新归为双门齿有袋动物科, 并将中新世晚期的Pyramios alcootense认作它亲缘关系最近的分子, 是很重要的, 因为它直接挑战这样一个正统观点:新几内亚双门齿有袋类辐射只发生于Zygomaturinae之内;还说明目前对新几内亚古动物地理学的了解可能比起初认为的要复杂得多。上新世Awe Local 动物群中N. watutennse的鉴定在澳大利亚也具有重要意义, 因为Nototherium目前只见于更新世沉积物中, 表明该属的时间分布范围其实更大些, 或者其中间类型还有待发现。

Key words:

• Diprotodontinae
• Nototherium
• New Guinea
• palaeozoogeography

Acknowledgements

I wish to thank Karen Black, Michael Archer and Sue Hand and for their helpful comments on the manuscript. Ralph Molnar (retired), Queensland Museum; Bob Jones, Australian Museum; Tom Rich, National Museum of Victoria; Chris Tassel, Queen Victoria Museum; Neville Pledge (now retired), South Australian Museum; and John Long, (previously) Western Australian Museum, provided access to specimens in their institutions. Study of late Cenozoic diprotodontids was supported by Australian Research Council Grants (AA00103792 and DP0453262 to M. Archer); National Estate Program Grant (to M. Archer and A. Bartholomai); the Queensland and Australian Museums; the Australian Geographic Society; and the University of New South Wales. Ernie Lundelius and Gilbert Price kindly reviewed the paper. Sarah Stewart and Lan Zhang assisted in preparing the figures and tables.