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 † Microbiotherium SPECIES SCORED: † Microbiotherium tehuelchum . GEOLOGICAL PROVENANCE OF SCORED SPECIMENS : Santa Cruz Formation, Santa Cruz Province , Argentina . AGE OF SCORED SPECIMENS: The Santa Cruz Formation spans a maximum of 14–19 Mya (see account for † Stilotherium , above). ASSIGNED AGE RANGE : 19.000 –14.000 Mya. REMARKS: † Microbiotherium tehuelchum is the only fossil microbiotheriid currently known from anything other than isolated dental remains (Segall, 1969; Marshall, 1982). Of particular importance is a partial auditory region (PU 15038) that exhibits a number of distinctive cranial features that are seen only in Dromiciops among living marsupials (Segall, 1969). We scored our † Microbiotherium terminal based solely on specimens of † M. tehuelchum from the Santa Cruz Formation (Segall, 1969; Marshall, 1982). However, material from the?middle Miocene (Friasian SALMA ) Río Frias Formation in Chile (Marshall, 1990) and the early Miocene Pinturas Formation in Argentina (Bown and Fleagle, 1994; Chornogubsky and Kramarz, 2012) has also been referred to † M. tehuelchum . Goin and Abello (2013) presented a phylogenetic analysis of Microbiotheriidae , including † M. tehuelchum , based on 20 dental characters.