A comparison of skull morphology in the marsupial bandicoot genus lsoodon: its taxonomic implications and notes on a new species, lsoodon arnhemensis.

Abstract

A series of 763 skulls of the genus Isoodon, comprising all known forms from Australia and Papua New Guinea, has been examined in order to review the taxonomy of the group. Original type descriptions of all forms (species and subspecies) have been compared with our findings and a new species, Isoodon arnhemensis, is described from Cape Arnhem, Northern Territory. Particular attention has been given to a large series of skulls of lsoodon macrourus which were collected at this laboratory in the course of other studies. This series includes many skulls of animals bred in captivity and of known or estimated age, which were used in growth studies, as well as skulls of wild animals. The skulls were assigned to dental age classes based on tooth eruption, replacement and wear. The captive diet caused considerable damage to the skulls and teeth of some animals caged indoors for more than two years. Anatomical features as well as measurements were used to compare the various forms which we consider belong to the following seven species: I. obesulus – New South Wales, Victoria, Tasmania (including West Sister Island, Bass Strait), South Australia and Western Australia; I. macrourus – New South Wales, Queensland, Western Australia, Northern Territory and Papua New Guinea ; I. nauticus – Nuyts Archipelago (South Australia); I. peninsulae – Queensland; I. auratus – Western Australia, Northern Territory and South Australia; I. barrowensis – Barrow Island (Western Australia) ; I. arnhemensis n. sp. – Northern Territory.