New specimens of ektopodontids (Marsupialia: Ektopodontidae) from South Australia

Abstract

Knowledge about the extinct phalangeroid family Ektopodontidae is increased by the discovery of new material from several localities. Previously unknown teeth of Chunia illuminata and Ektopodon stirtoni are described respectively from White Sands Basin and Mammalon Hill, Lake Palankarinna, Lake Eyre Basin, South Australia, with M1 being recorded for the first time for any species of Chunia., and a full maxilla of Ektopodon stirtoni showing the positional relationship between P3 and M1 for the first time; this is even more extreme than the arrangement postulated previously. Another species Ektopodon litolophus has been described on the basis of an M1 found at the Leaf Locality, Lake Ngapakaldi, Lake Eyre Basin. Material from Lake Tarkarooloo, referred to Ektopodon stirtoni, is redescribed as a new species Ektopodon tommosi. Comparisons of M1 of Chunia and Ektopodon species now allow evolutionary trends, such as increasing number of cusps on the molar lophs, and simplification of the cusps, to be discerned.