Marsupial Lions, Thylacoleonidae, are an extinct group of carnivorous Mammals from the Cainozoic of Australia. Many of these animals were large in size and showed dentition associated with a hypercarnivorous diet (diet composed almost entirely of meat), and are assumed to have been the top predators in the ecosystems where they lived. Members of the genus Wakaleo are dog-sized animals known from the Oligocene and Miocene of South Australia, Northern Territory and Queensland.
In a paper published in the Journal of Systematic Biology on 6 December 2017, Anna Gillespie, Michael Archer and Suzanne Hand of the PANGEA Research Centre at the University of New South Wales, describe a new species of Wakaleo from the late Oligocene to early Miocene sediments of the Riversleigh World Heritage Area in Queensland, Australia.
The new species is named Wakaleo schouteni, in honour of palaeoartist Peter Schouten, for his reconstructions of the Riversleigh fauna and other prehistoric Australian animals. It is described from an almost complete skull, preserved in two halves, with most molar teeth intact, plus several fragmentary jaw sections, and a left and right humerus (from separate locations).
Wakaleo schouteni; (A) left lateral view; (B) left lateral view with jugal removed (hatched area) and M4 included; (C), posterior view. Abbreviations: al, alisphenoid; C, canine; eam, external auditory meatus; fm, foramen magnum; for, foramen rotundum; fr, frontal; iof, infraorbital foramen; jg, jugal; lac, lacrimal; lacf, lacrimal foramen; M, molar; max, maxilla; mf, maxillary foramen; mp, mastoid process; ms, mastoid; nc, nuchal crest; ns, nasal; oc, occipital condyle; os, orbitosphenoid; P, premolar; pal, palatine; par, parietal; pgp, postglenoid process; pmx, premaxilla; pop, paroccipital process; pt, pterygoid; ptp, pterygoid process of the alisphenoid; sc, sagittal crest; so, supraoccipital; sof, sphenorbital fissure; sop, supraorbital process; spf, sphenopalatine foramen; sq,squamosal; ssf, subsquamosal fossa; tvc, transverse canal. Gillespie et al. (2017).
Wakaleo schouteni is one of the smallest members of the genus, with a total skull length of 164 mm, and an estimated living mass of between 22.6 and 24.0 kg (comparable to a Dalmation or Collie Dog). It is also one pf the earliest known members of the group, and has somewhat generalised dentition, something generally associated with an omnivorous diet, rather than a carnivorous one. This suggests that the genus may have began as small omnivorous animals with only a low amount of meat in their diet, then grown larger over time as they became more-and-more specialised for carnivorey, a pattern known from a variety of other groups.
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