An early Pleistocene record of a giant koala (Phascolarctidae: Marsupialia) from western Victoria.

Abstract

THE pre Holocene-Late Pleistocene record of Phascolarctos in Australia is extremely meagre. There are at least two, possibly three extinct species of Phascolarctos in addition to the extant Phascolarctos cinereus (Black 1999). P. yorkensis (syn. Cundokoala yorkensis; Black and Archer 1997) is known from the Early Pliocene Curramulka Local Fauna, South Australia (SA), and the Late Pleistocene Wellington Caves Local Fauna, New South Wales (Archer et al. 1997; Pledge 1992). P. stirtoni occurs in the Late Pleistocene Cement Mills Local Fauna, Queensland, and is known only from a partial maxilla containing P3-M2 (Bartholomai 1968, 1977). Phascolarctos material from the mid- Pleistocene Victoria Fossil Cave and Spring Cave, Naracoorte, SA, have also been referred to P. cf. stirtoni but remain undescribed (Reed and Bourne 2000; Moriarty et al. 2000). P. maris is known from a single lower molar from the Early Pliocene Sunlands Local Fauna, SA (Pledge 1987). Black (1999) cast doubt on its validity, suggesting its features may fall within the intraspecific variation of P. stirtoni. If P. maris is referable to P. stirtoni it is another South Australian instance of this species, and extends its range back to the Early Pliocene. The new phascolarctid material documented here is from the early Pleistocene Nelson Bay Local Fauna, Portland, Victoria (141o 35’ E; 38o 36’ S). It is therefore an important additional southern occurrence of a species larger than the living P. cinereus, and is the only pre- Late Pleistocene record of the Phascolarctidae in Victoria.