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. Remains similar to
Bishops are known from the mid Cretaceous
Mata Amarilla Formation of Argentina, suggesting faunal interchange. ==References==