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 † Evolestes SPECIES SCORED: † Evolestes hadrommatos ( type and only described species), † Evolestes sp. GEOLOGICAL PROVENANCE OF SCORED SPECIMENS : Unit 6 of the Salla Beds, La Paz Department , Bolivia († Evolestes hadrommatos ); GBV-19 (“La Cantera” locality), Unit 3, Upper Puesto Almendra Member, Sarmiento Formation, Gran Barranca south of Lake Colhue-Huapi, Sarmiento Department, Chubut Province , Argentina († Evolestes sp. ). AGE OF SCORED SPECIMENS: Unit 6 (= “the Upper White interval”) of the Salla Beds is 25.82–25.89 Mya (i.e., late Oligocene) based on radiometric and magnetostratigraphic evidence (Kay et al., 1998: 191, fig. 2), whereas the “La Cantera” fossil locality is 29.5–31.1 Mya based on magnetostratigraphy (Ré et al., 2010: 57). ASSIGNED AGE RANGE : 31.100 –25.820 Mya. REMARKS: † Evolestes hadrommatos is known from a single partial cranium (the holotype MNHN-BOL-V-004017 [previously MNHN- BOL-96-400]; Goin et al., 2007). Of particular interest for this study, this specimen exhibits a molar dentition that is markedly more plesiomorphic than that of any extant paucituberculatan (Abello, 2007; Goin et al., 2007, 2010; Abello, 2013). Subsequently, additional dental material assignable to † Evolestes and possibly representing a new species was described from the “La Cantera” locality at the Gran Barranca in Argentina (Goin et al., 2010; Abello, 2013). The La Cantera material is important because it includes lower molars, which have not been described for † E. hadrommatos . Goin et al. (2010) thought that † Evolestes might be a caenolestid, but such a familial assignment is not supported by published phylogenetic analyses (Goin et al., 2007, 2009a; Abello, 2013; Forasiepi et al., 2013; Rincón et al., 2015; Engelman et al., 2016; Abello et al., 2020), which instead suggest that † Evolestes represents an early-branching lineage within Paucituberculata .