Hypsiprymnodon bartholomaii Ramsay 1876

Hypsiprymnodon

SPECIES SCORED: Hypsiprymnodon † bartholomaii .

GEOLOGICAL PROVENANCE OF SCORED SPECIMENS: Riversleigh Faunal Zone C, Riversleigh World Heritage Area, Queensland, Australia.

AGES OF SCORED SPECIMENS: Riversleigh Faunal Zone C is interpreted to be middle Miocene based on biostratigraphy (see above). In the absence of radiometric dates, we have assumed the entire span of the middle Miocene (Langhian to Serravallian; Cohen et al., 2013 [updated]) for this terminal.

ASSIGNED AGE RANGE: 15.97–11.63 Mya.

REMARKS: Hypsiprymnodon † bartholomaii was described by Flannery and Archer (1987a) based on a partial cranium and two isolated molars, all from the Gag Site, which is part of Riversleigh Faunal Zone C. If this taxon is indeed referable to Hypsiprymnodon, then it indicates that the genus originated prior to the middle Miocene. However, Flannery and Archer (1987a) noted a number of striking craniodental differences between H. † bartholomaii and the Recent species H. moschatus, notably parietal-alisphenoid versus frontal-squamosal contact and presence versus absence of a distinct postglenoid process. Three further fossil Hypsiprymnodon species have recently been described from Riversleigh Faunal zones B and C sites (Bates et al., 2014), but we did not examine these for scoring purposes. Some phylogenetic analyses have found Hypsiprymnodon to be polyphyletic (Black et al., 2014c; den Boer and Kear, 2018: fig. S11), others have found it to be paraphyletic (den Boer and Kear, 2018: figs. S9–10), and still others have failed to unambiguously support its monophyly (Bates et al., 2014; Butler et al., 2016, 2018; den Boer and Kear, 2018: supplemental data), but that of Travouillon et al. (2016) placed Recent and fossil Hypsiprymnodon species in a clade that also included the propleopines, † Ekaltadeta, † Jackmahoneya, and † Propleopus.