Microleo (†Microleo attenboroughi (Gillespie, Archer, Hand 2016))
Dimensions: length - 30–35 cm long (excluding the tail), height - 15 сm, weight 500 - 800 g
Temporal range: lived in Australia (Early Miocene ~ 18 million years ago)
Microleo attenboroughi is a very small species of the Thylacoleonidae family of marsupials from the Early Miocene of Australia, living in the wet forest that dominated Riversleigh about 18 million years ago. The genus Microleo is currently known from a broken palate and two pieces of jaw, containing some teeth and roots that correspond to those found in other species of thylacoleonids. It was found in Early Miocene-aged deposits of the Riversleigh fossil site in Queensland, regarded as one of the most significant palaeontological sites yet discovered, and named for the naturalist David Attenborough in appreciation of his support for its heritage listing. The anatomy of Microleo suggests the genus is basal to all the known thylacoleonids, known as the marsupial lions, although its relative size prompted one discoverer to describe it as the "feisty" kitten of the family.
A very small and probably arboreal species of thylacoleonid was considered to be tiny, when compared with the previously known thylacoleonid weight range of 2 to 130 kilograms. Microleo lived in a period around 18 million years ago in the wet forested environment, preying on a rich variety of the fauna that was present in the same period.
The weight of M. attenboroughi is estimated to have been around 600 grams, the smallest of the family, but a larger predator amongst the contemporary vertebrate fauna of the earlier Miocene. The premolars of the species are sharpened and elongated, these pointed and knife edge teeth and basin like molars are characteristic of the family.
When describing the new species for a press release, the palaeontologist and leading author Anna Gillespie was quoted as saying, "Microleo attenboroughi would have been more like the cute but still feisty kitten of the family Thylacoleonidae."