Stagodontidae

The family Stagodontidae was proposed by Marsh (1889 c, p. 178) for the inclusion of Stagodon nitor, the genotypic species, and S. tumidus. The type specimen of S. nitor, a worn premolar, however, was later shown by Clemens (1966, p. 55) to belong to Didelphodon Marsh (1889 b). In accordance with the rules established by the International Code of Zoological Nomenclature [Art. 23 (d) and 40], Clemens (1966) retained the family Stagodontidae in preference to the other family group names, Thlaeodontinae Cope (1892), Didelphodontinae Simpson (1927 b), and Thlaeodontinae Hay (1930). The family Stagodontidae as redefined by Clemens (1966, p. 55) consists of " Large, late Cretaceous, North American marsupials in which the trigonids are anteroposteriorly shortened and paraconid and protoconid are of subequal height, and higher than the metaconid. Epitympanic sinus is large and of complex structure. Alisphenoid lacks an entoglenoid process. Bullae are well developed, apparently formed of both alisphenoid and petrosal elements. " Boreodon and Didelphodon are included in the family Stagodontidae in the present paper, but Eodelphis is excluded.