The most recent and physically largest in size of all the thylacoleonid genera.  Members of this genus range from the size of a large dog to the the size of a small lion.  The most famous member of the genus is the Pleistocene T. carnifex, whose remains have been well preserved in various cave deposits in South Australia and New South Wales.

    Thylacoleo crassidentatus:

   This was a Pliocene species of Thylacoleo which was about the size of a large dog.  Its remains have been recovered from the Chinchilla Local Fauna of the Chinchilla Sand, southeastern Queensland.  Additional fossils of Thylacoleo referable to this species have been found in the Allingham Formation (Bluff Downs local fauna) of northern Queensland and the Bow local fauna of northeastern New South Wales.

    The specimen depicted is a fragment of the left side of the skull with several teeth in very good condition.

    A small Pliocene species of Thylacoleo, the holotype of which (an isolated left P3) was found at Town Cave, Curramulka, York Peninsula, South Australia.  This species was only about half the size of T. crassidentatus.  Additional specimens referable to T. hilli were found in 1979 at the Bow fossil site by students and staff of the of the University of New South Wales.

    Shown at right are two views of a dentary fragment of this species.  This specimen retains a well preserved P3 and partial I1.

    Widespread across Australia, and surviving into the late Pleistocene (40,000 years ago), T. carnifex was the largest and the last of the thylacoleonids.  Many fine fossil examples of this species have been unearthed in cave deposits.  It is the only thylacoleonid of which a complete skeleton has been found.