|Figure 1: Thylacinus yorkellus, holotype SAM P29807, incomplete left dentary. Photographs of the specimen. |
(A) Lateral view (B) medial view (C) dorsal view. Scale bar = 50 mm. Photographs by Steven Jackson.
Thylacinus yorkellus is described as a new, moderately small-bodied species of thylacinid from the latest Miocene or, more likely, earliest Pliocene of South Australia. The new species can be diagnosed by the autapomorphic presence a strongly developed precingulid that terminates in a cuspidule on the anterobuccal face of the paraconid of the lower molars and a tiny basal anterior cuspidule on P2, P3 and the lower molars. It is found by cladistic analysis to be the sister species of the recently extinct Th. cynocephalus and distinct from the approximately coeval Th. megiriani from the Northern Territory. New dentary material is described and referred to Th. megiriani. These add character data and allow this species to be re-diagnosed based on autapomorphic character traits. Each of the three known late Miocene to early Pliocene Thylacinus species (Th. potens, Th. megiriani and Th. yorkellus) suggest that, instead of declining, there was a modest radiation of Thylacinus in the late Miocene.
Dasyuromorphia Gill, 1872
Thylacinidae Bonaparte, 1838
Thylacinus Temminck, 1824
Thylacinus yorkellus sp. nov.
Holotype. South Australian Museum (hereafter SAM) P29807, incomplete left dentary with C, P1−3 and M2−3 (Figs. 1–2 and Table 1).
Locality and stratigraphic age. Corra-Lynn Cave, approximately 3 km south of Curramulka, York Peninsula, South Australia. Late Miocene or, more likely, early Pliocene in age.
Etymology. From York Peninsula and the diminutive suffix–ellus (Latin), referring to its small size relative to Th. cynocephalus.
Yates, AM. 2015. Thylacinus (Marsupialia: Thylacinidae) from the Mio-Pliocene Boundary and the Diversity of Late Neogene Thylacinids in Australia. PeerJ 3:e931. DOI: 10.7717/peerj.931