Nimbacinus dicksoni, Muirhead & Archer, 1990

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 : 323-324

† Nimbacinus

SPECIES SCORED: † Nimbacinus dicksoni (type species).

GEOLOGICAL PROVENANCE OF SCORED SPECIMENS: AL90 and Henk’s Hollow sites (Riversleigh Faunal Zone C), Riversleigh World Heritage Area, Queensland, Australia.

AGE OF SCORED SPECIMENS: Riversleigh Faunal Zone C is interpreted to be middle Miocene based on biostratigraphy (Archer et al., 1989, 1994, 1995, 1997, 2006; Creaser, 1997;; Travouillon et al., 2006; Black et al., 2012b, 2013; Woodhead et al., 2014; Arena et al., 2015). AL90 site has been radiometrically dated as 14.17–15.11 Mya (Woodhead et al., 2014), but such dates are currently unavailable for Henk’s Hollow site, so we conservatively assume the entire span of the middle Miocene (Langhian-Serravallian; Cohen et al., 2013 [updated]) for this taxon.

ASSIGNED AGE RANGE: 15.970 –11.630 Mya.

REMARKS: † Nimbacinus dicksoni was originally described by Muirhead and Archer (1990) based on fragmentary dental material, most of it from the Riversleigh Henk’s Hollow site. Subsequently, a nearly complete cranium and associated mandibles (QM F36357) from the Riversleigh AL90 site were described by Wroe and Musser (2001); this specimen also includes an associated skeleton (Long et al., 2002: 61), which remains undescribed. Muirhead and Archer (1990) also identified a broken m2 from D Site at Riversleigh (Faunal Zone A, probably late Oligocene; see † Badjcinus above) and a partial right mandible from the Bullock Creek Local Fauna (probably middle Miocene; see † Mutpuracinus above) in the Northern Territory as representing † N. dicksoni . Subsequently, Murray and Megirian (2000) referred the Bullock Creek specimen mentioned by Muirhead and Archer (1990) to a new species, † N. richi , together with several additional Bullock Creek thylacinid specimens. Murray and Megirian (2000) also suggested that the D Site specimen represents a third distinct taxon. Wroe and Musser (2001) agreed with Murray and Megirian (2000) that the D Site specimen is probably not † N. dicksoni , but they questioned whether † N. richi should be recognized as a distinct species. Most recently, Rovinsky et al. (2019) concluded that † N. richi is probably synonymous with † N. dicksoni , and considered the D Site specimen referred to N. dicksoni by Muirhead and Archer (1990) to be Thylacinidae incertae sedis. Only specimens of † N. dicksoni from the Riversleigh Henk’s Hollow and AL90 sites have been used for scoring purposes here.

Published phylogenetic analyses consistently support thylacinid affinities for † Nimbacinus (Wroe and Musser, 2001; Murray and Megirian, 2006a; Yates, 2014, 2015b; Archer et al., 2016; Kealy and Beck, 2017; Rovinsky et al., 2019).