Ngapakaldia bonythoni (Marsupialia, Diprotodontidae): new material from Riversleigh, northwestern Queensland, and a reassessment of the genus Bematherium

New fossil material of the extinct marsupial Ngapakaldia bonythoni from Riversleigh, Queensland, extends its known temporal and geographic range into multiple Oligo-Miocene deposits. The exceptional preservation of these fossils allowed for a detailed description of previously unknown cranial and dental features, supporting the reassessment that Bematherium angulum is a junior synonym of N. bonythoni. While N. bonythoni shares morphological similarities with its smaller congener N. tedfordi, their distinct distributions—N. tedfordi absent at Riversleigh—reinforce their separation as two species. The shared presence of N. bonythoni across multiple Faunal Zone A deposits and the Ngapakaldi Local Fauna further supports a late Oligocene age for these sites.

Black, K. H. (2010). Ngapakaldia bonythoni (Marsupialia, Diprotodontidae): new material from Riversleigh, northwestern Queensland, and a reassessment of the genus Bematherium. Alcheringa: An Australasian Journal of Palaeontology, 34(4), 471–492. https://doi.org/10.1080/03115511003793496