Like other Australosphenida, ausktribosphenids have tribosphenic molars.
Distribution
Given that Ausktribosphenidae has been found in Early Cretaceous deposits in Australia, its occurrence has ramifications for knowledge of early monotreme paleobiogeography because Australia was connected only to Antarctica, and placentals originated in the northern hemisphere and were confined to it until continental drift formed land connections from North America to South America, from Asia to Africa and from Asia to India. The late Cretaceous map[4] shows how the southern continents are separated. However, the cladistic analysis of Cifelliodon recovers Fruitafossor as a monotreme relative, suggesting that yinotherians may have originated in the Northern Hemisphere.[5] Remains similar to Bishops are known from the mid Cretaceous Mata Amarilla Formation of Argentina, suggesting faunal interchange.[6]
References
^Rich, Thomas H.; Vickers-Rich, Patricia; Constantine, Andrew; Flannery, Timothy F.; Kool, Lesley; van Klaveren, Nicholas (1997). "A Tribosphenic Mammal from the Mesozoic of Australia". Science. 278 (5342): 1438–1442. doi:10.1126/science.278.5342.1438. JSTOR2894756. PMID9367951.
^Thomas H. Rich; Peter Trusler; Lesley Kool; David Pickering; Alistair Evans; Karen Siu; Anton Maksimenko; Martin Kundrat; Neil J. Gostling; Steven Morton; Patricia Vickers-Rich (2020). "A third, remarkably small, tribosphenic mammal from the Mesozoic of Australia". In Guntupalli V.R. Prasad; Rajeev Patnaik (eds.). Biological consequences of plate tectonics. New perspectives on post-Gondwana break-up–A tribute to Ashok Sahni. Vertebrate Paleobiology and Paleoanthropology. Springer. pp. 67–75. doi:10.1007/978-3-030-49753-8_3. ISBN978-3-030-49752-1. S2CID229618594.
^Adam K. Huttenlocker; David M. Grossnickle; James I. Kirkland; Julia A. Schultz; Zhe-Xi Luo (2018). "Late-surviving stem mammal links the lowermost Cretaceous of North America and Gondwana". Nature. in press. doi:10.1038/s41586-018-0126-y.