Ausktribosphenidae is a family of mammals from the Early Cretaceous of Australia that are closely related to monotremes.
Classification and taxonomy
Ausktribosphenidae is closely related to monotremes
and hence the two form the yinotherian clade Australosphenida
. It includes two species, ''Ausktribosphenos nyktos
'' and ''Bishops whitmorei
'', both of which are known only from skull and jaw fragments.
Like other Australosphenida, ausktribosphenids have tribosphenic molars
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 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.
[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.]
Category:Cretaceous mammals of Australia
Category:Prehistoric mammal families