Character set and phylogenetic analyses of the living and fossil egerniine scincids of Australia

The diverse living Australian lizard fauna contrasts greatly with their
limited Oligo-Miocene fossil record. New Oligo-Miocene fossil vertebrates
from the Namba Formation (south of Lake Frome, South Australia) were
uncovered from multiple expeditions from 2007–2018. Abundant
disarticulated material of small vertebrates was concentrated in shallow
lenses along the palaeo-lake edges, now exposed on the western shore. The
fossiliferous lens occurring within the Namba Formation, also known from
Billeroo Creek 2 km northeast of Lake Pinpa, includes abundant aquatic
(such as fish, platypus Obdurodon, and waterfowl) and diverse terrestrial
(such as possums, dasyuromorphs, and scincids) vertebrates and is
hereafter recognised as the Fish Lens. The stratigraphic provenance of
these deposits in relation to prior finds in the area is also established.
A new egerniine scincid taxon Proegernia mikebulli sp. nov. described
herein, is based on a near-complete reconstructed mandible, maxilla,
premaxilla, and pterygoid. Postcranial scincid elements were also
recovered with this material, but could not yet be confidently associated
with P. mikebulli. This new taxon is recovered as the sister species to P.
palankarinnensis, in a tip-dated total-evidence phylogenetic analysis,
where both are recovered as stem Australian egerniines. These taxa also
help pinpoint the timing of the arrival of scincids to Australia, with
egerniines the first radiation to reach the continent.