Dasyuromorphia Gill, 1872

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 : 217-218

Dasyuromorphia Gill, 1872

CONTENTS: † Badjcinus , † Barinya , Dasyuridae , † Mutpuracinus , Myrmecobius , and Thylacinidae .

STEM AGE: 43.7 Mya (95% HPD: 39.6–47.4 Mya).

CROWN AGE: 31.2 Mya (95% HPD: 26.6–36.5 Mya).

UNAMBIGUOUS CRANIODENTAL SYNAPOMOR- PHIES: Nasals not produced beyond premaxillary facial processes, incisive foramina exposed in dorsal view (char. 1: 0→1; ci = 1.000); postorbital processes present (char. 18: 0→1; ci = 0.042); posterolateral palatal foramina absent, posterior margins incomplete (char. 40: 0→1; ci = 0.200); stD taller than stB on M2 (char. 134: 0→1; ci = 0.250); m3 hypoconid lingual to salient protoconid (char. 173: 0→1; ci = 0.045); and lower molars with distinct posterior cingulid (char. 180: 0→1; ci = 0.333).

COMMENTS: Monophyly of Dasyuromorphia sensu Kealy and Beck (2017) —the most inclusive clade including Dasyurus viverrinus , but excluding Perameles nasuta , Notoryctes typhlops , Phalanger orientalis , and Dromiciops gliroides —is strongly supported in our total-evidence analyses (figs. 32, 33). This clade is supported by six unambiguous craniodental synapomorphies, of which four—nasals not produced beyond premaxillary facial processes, posterolateral palatal foramina absent, stD taller than stB on M2, and lower molars with distinct posterior cingulid present—show little or no homoplasy.

† Badjcinus turnbulli from the late Oligocene (Faunal Zone A) of Riversleigh World Heritage area was originally described as a thylacinid (see Muirhead and Wroe, 1998), and it is placed in Thylacinidae sensu Kealy and Beck (2017 : table 1) in our undated total-evidence analysis (fig. 32). However, in our dated total-evidence analysis, † Badjcinus is placed in a trichotomy with Thylacinidae († Nimbacinus + Thylacinus ) and a clade comprising our remaining dasyuromorphian terminals ( fig. 33). It is, therefore, unclear whether † Badjcinus is a member of the dasyuromorphian crown clade (= Dasyuroidea; Kealy and Beck, 2017). 32 In this respect, our results are broadly similar to those of Kealy and Beck (2017), who also failed to unambiguously place

32 † Badjcinus exhibits a carnivorously adapted dentition that most closely resembles those of other taxa currently placed in Thylacinidae (see Muirhead and Wroe, 1998), but it has some unusual features—most notably, fusion between stB and the paracone on M1 (char. 136), which is not seen in definitive thylacinids, but which is seen in several dasyurids (e.g., Dasycercus , Dasyuroides , Dasyurus , Sarcophilus )— together with a seemingly plesiomorphic basicranium. Most strikingly, it lacks a posterior squamosal epitympanic sinus (char. 84), a structure that is present in all other known dasyuromorphians ( Archer, 1976b; Muirhead and Wroe, 1998).

† Badjcinus within Thylacinidae , despite a much denser sampling of dasyuromorphians than that used here; instead, it was placed as sister to all other dasyuromorphians in some analyses, congruent with its antiquity (late Oligocene) and putative basicranial plesiomorphies. Kealy and Beck (2017) argued that † Badjcinus is best considered? Thylacinidae , based on current evidence. By contrast, the phylogenetic analyses of Rovinsky et al. (2019) consistently placed † Badjcinus within Thylacinidae , but these employed a less dense sampling of dasyuromorphian taxa than those of Kealy and Beck (2017).