Evolestes

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 : 319

† 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 .