Figure 1. The dentary of Early Cretaceous Bishops (1.5cm long) compared to its Late Cretaceous sister, Asioryctes, which has fewer and larger premolars and one more molar.
The genus Bishops whitmorei
(Rich et al. 2001; Early Cretaceous, Australia; Fig.1) is represented by a small mandible with a high coronoid process, six premolars and only three molars. In the LRT it nests basal to the much larger carnivorous marsupials (= creodonts), starting with the wolf-sized Arctocyon. It is a sister to Asioryctes (Fig. 1) which is basal to the herbivorous marsupials of Australia.
What makes this important?
It is the only tiny creodont known. All others are dog to wolf-sized. Cenozoic descendants of Bishops include the following carnivorous marsupials: Thylacinus, Thylacosmilus, Borhyaena, Hyaenodon and Vincelestes.
References
Rich TH, Flannery TF, Trusler P. Kool L, van Klaveren NA and Vickers-Rich P 2001. A second tribosphenic mammal from the Mesozoic of Australia. Records of the Queen Victoria Museum 110: 1-9.
The Pterosaur Heresies 