Muramura

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 : 332

† Muramura

SPECIES SCORED: † Muramura williamsi (type species), † M. pinpensis .

GEOLOGICAL PROVENANCE OF SCORED SPECIMENS: SAM PL 8307 (Member 5) locality, Zone A (“Minkina” or “wynyardiid” Local Fauna), Lake Palankarinna, Etadunna Formation, South Australia († M. williamsi ); AMNH site B, Zone B (Pinpa Local Fauna) Namba Formation, Lake Pinpa, South Australia († M. pinpensis ).

AGE OF SCORED SPECIMENS: See † Ilaria above, for a discussion of the ages of the Etadunna and Namba formations. In the absence of radiometric dates, we have assumed the entire span of the late Oligocene (Chattian; Cohen et al., 2013 [updated]) for this terminal.

ASSIGNED AGE RANGE: 27.820 –23.030 Mya.

REMARKS: The diprotodontian family † Wynyardiidae takes its name from † Wynyardia bassiana, which is known from a single incomplete skull and associated partial postcranial skeleton collected from Table Cape (near Wynyard) in Tasmania some time before 1876 (Spencer, 1901). Unfortunately, this specimen had lost its entire dentition through erosion prior to discovery. Largely as a result of this lack of dental evidence, the relationships of † Wynyardia were controversial for many years (Spencer, 1901; Osgood, 1921; Jones, 1930; Gill, 1957; Ride, 1964; Haight and Murray, 1981). However, Aplin’s (1987) careful study of the wellpreserved auditory region of the holotype clearly supports diprotodontian, and most likely vombatiform, affinities. Tedford et al. (1977) tentatively referred a number of fossil diprotodontian specimens from Lake Pinpa to † Wynyardiidae based on postcranial similarities to † W. bassiana; this material was ultimately described as † Muramura pinpensis by Pledge (2003). Prior to this, Pledge (1987a) had described † Muramura williamsi based on two virtually complete skeletons from the Minkina Local Fauna, Lake Palankarinna, in the Etadunna Formation. We used specimens of both † M. pinpensis and † M. williamsi to score a composite † Muramura terminal. The cranial morphology of † Muramura has yet to be described in detail, but the molar dentition is noteworthy (as is that of the second wynyardiid included here, † Namilamadeta ; see below) in that it appears to be intermediate between selenodont and lophodont-type morphologies (Pledge, 1987a: fig. 2; 2003: fig. 19.2; Beck et al., 2020). Doubts have been expressed as to whether † Wynyardiidae (comprising the genera † Wynyardia , † Muramura , and † Namilamadeta ) is monophyletic (Aplin and Archer, 1987: xlviii; Long et al., 2002: 117). However, the phylogenetic analyses of Pledge (2005)—who included all three genera—and Beck et al. (2020)—who did not include † Wynyardia due to the poor preservation of the only known specimen—both supported the monophyly of † Muramura + † Namilamadeta .