Nimiokoala greystanei, Black & Archer, 1997

Beck, Robin M. D., Voss, Robert S. & Jansa, Sharon A., 2022, Craniodental Morphology And Phylogeny Of Marsupials, Bulletin of the American Museum of Natural History 2022 (457), pp. 1-353 : 327-328

† Nimiokoala

SPECIES SCORED: † Nimiokoala greystanei (type and only described species).

GEOLOGICAL PROVENANCE OF SCORED SPECIMENS: Boid Site East (BSE) (Riversleigh Faunal Zone A or B), Riversleigh World Heritage Area, Queensland, Australia; Camel Sputum, Inabeyance, Neville’s Garden, Rat Vomit, Dirk’s Towers, and Upper sites (Riversleigh Faunal Zone B), Riversleigh World Heritage Area, Queensland, Australia.

AGE OF SCORED SPECIMENS: Arena et al. (2015) concluded that Boid Site East (BSE) was either Riversleigh Faunal Zone A or B; all other † N. greystanei specimens used here are from Riversleigh Faunal Zone B sites (Arena et al., 2015; Travouillon et al., 2006; Woodhead et al., 2014). Based on biostratigraphy, Riversleigh Faunal Zone A is interpreted to be late Oligocene, and Riversleigh Faunal Zone B is interpreted to be early Miocene (see above).

ASSIGNED AGE RANGE: 27.820 –15.970 Mya.

REMARKS: † Nimiokoala greystanei is the second fossil phascolarctid for which relatively well-preserved craniodental material is available, namely a partial cranium (QM F30483) that was described in detail by Louys et al. (2009). Black and Archer (1997b) described the dentition of † N. greystanei , based on QM F30483 and several other, less complete specimens. QM F30483 is from Boid Site East (BSE), which is part of Riversleigh Faunal Zone A or B (Arena et al., 2015; Travouillon et al., 2006; Woodhead et al., 2014), whereas the remaining specimens are from Faunal Zone B sites. Like † Litokoala (see above), † N. greystanei was smaller (estimated body mass of 2.6–4.1 kg; Black et al., 2014b) and appears to have had a less derived masticatory system (Louys et al., 2009) than the Recent koala Phascolarctos cinereus . In the phylogenetic analyses of Black et al. (2012a) and Beck et al. (2020), † Nimiokoala was recovered as sister to a clade that included Phascolarctos and † Litokoala .