Microleo is the smallest known thylacoleonid, being only the size of a
Grey squirrel (Sciurus carolinensis).
M. attenboroughi, named for British naturalist David Attenborough,
is currently known only from a palatal fragment containing an incomplete
row of teeth, from the Early Miocene of the Riversleigh World Heritage
Site, Queensland. The anatomy of Microleo suggests it is the
most primitive of all thylacoleonids, and that the family as a whole are
basal vombatomorphs that form the sister taxon of all other Vombatomorphia.
fragment of Microleo attenboroughi.
with that of Thylacoleo carnifex.
life reconstruction of Microleo attenboroughi. Courtesy: Peter
Late Oligocene - Middle
Members of the
genus Priscileo are small thylacoleonids about the size of a possum
or cuscus. The genus is currently represented by two species.
known only from a rather poorly preserved fossil maxillary fragment and
a few post-cranial bones recently found in the Late Oligocene Ngapakaldi
Local Fauna at Lake Pitakanta in northeastern South Australia.
From the Early Miocene
of the Riversleigh World Heritage Site, P. roskellyae
is known from a complete skull and most of the dentition.
skull of Priscileo roskellyae, shown as it was found in situ
among an assemblage of the bones of other other animals.
life reconstruction of Priscileo roskellyae.