Zatheria McKenna, 1975

Cifelli, Richard L., Davis, Brian M. & Sames, Benjamin, 2014, Earliest Cretaceous mammals from the western United States, Acta Palaeontologica Polonica 59 (1), pp. 31-52 : 44

Superorder Zatheria McKenna, 1975

Remarks.— Kielan-Jaworowska et al. (2004) defined the Zatheria as a node-based taxon to include the last common ancestor of Peramus Owen, 1871 + Boreosphenida Luo, Cifelli, and Kielan-Jaworowska, 2001, plus all of its descendants (see Prothero 1981 for a character-based definition encompassing the same taxa). As pointed out by Martin

2002), this definition excludes taxa (e.g., Amphitherium Blainville, 1838 ; Arguimus Dashzeveg, 1979 ; Nanolestes Martin, 2002 ) generally accepted as stem-lineage(s) to the same monophyletic group. We follow Martin (2002) in recognizing the Zatheria as a stem-based taxon, including all mammals more closely related to the Tribosphenida McKenna, 1975 (=Boreosphenida, see Davis 2011b) than to the Dryolestoidea . We follow Lopatin and Averianov (2006b) and Davis (2011a) in referring to the single talonid cusp as a hypoconid rather than a hypoconulid ( Kielan-Jaworowska et al. 2004) or simply “talonid cusp” ( Sigogneau-Russell 2003).