Illustration of Bishops
Image: Peter Trusler
Source: Peter Trusler
The fossil jaw of Bishops
Image: Jon Augier
Source: Museum Victoria
This fossil jaw is 1.6 cm long.
Mammals lived alongside dinosaurs for over 100 million years before the mass extinction that ended the age of dinosaurs. However, these mammals were generally small and were probably nocturnal.
Tonnes of rock were searched to find this tiny fossil. This mammal, called Bishops, was a small shrew-like creature that lived in the forests of the Victorian polar rift valley. Bishops is one of several types of mammals found in these Cretaceous sediments in Victoria, and for the most part it appears these mammals were extremely small.
The discovery in 1997 of tiny mammal jaws in Cretaceous sediments suggested that placental mammals, along with monotremes and an entirely extinct group of mammals called multituberculates, lived in Australia before marsupials, challenging previously held ideas about mammals in Australia.