Craniodental Morphology And Phylogeny Of Marsupials
Author
Beck, Robin M. D.
School of Science, Engineering and Environment University of Salford, U. K. & School of Biological, Earth & Environmental Sciences University of New South Wales, Australia & Division of Vertebrate Zoology (Mammalogy) American Museum of Natural History
Author
Voss, Robert S.
Division of Vertebrate Zoology (Mammalogy) American Museum of Natural History
Author
Jansa, Sharon A.
Bell Museum and Department of Ecology, Evolution, and Behavior University of Minnesota
text
Bulletin of the American Museum of Natural History
2022
2022-06-28
2022
457
1
353
https://bioone.org/journals/bulletin-of-the-american-museum-of-natural-history/volume-457/issue-1/0003-0090.457.1.1/Craniodental-Morphology-and-Phylogeny-of-Marsupials/10.1206/0003-0090.457.1.1.full
journal article
10.1206/0003-0090.457.1.1
0003-0090
6971356
†
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
.