Gingerichia, Zack & Penkrot & Krause & Maas, 2005

Zack, Shawn P., Penkrot, Tonya A., Krause, David W. & Maas, Mary C., 2005, A new apheliscine “ condylarth ” mammal from the late Paleocene of Montana and Alberta and the phylogeny of “ hyopsodontids ”, Acta Palaeontologica Polonica 50 (4), pp. 809-830 : 811

Subfamily Apheliscinae Matthew, 1918

Included genera.— Apheliscus Cope, 1875 , Phenacodaptes Jepsen, 1930 , Gingerichia gen. nov., possibly Epapheliscus Van Valen, 1966 .

Age and distribution.—Late Paleocene and early Eocene of western North America and possibly late Eocene or early Oligocene of Italy.

Revised diagnosis.—Apheliscines can be distinguished from other apheliscids by the following combination of features: p4 and P4 larger than preceding and succeeding teeth; p4 with large, tall protoconid; p4 paraconid and metaconid small or absent; p4 talonid simple, with basin weak to absent, and with single prominent cusp; lower molar protoconids and metaconids with inflated bases; lower molar buccal cingulids absent or present only in hypoflexids; paracone of P4 inflated, protocone small; P4 metacone absent or very weak; centrocrista of M1–3 interrupted at midlength because premetacrista begins buccal to termination of postparacrista.

Discussion.—The Apheliscinae previously comprised two North American genera, Phenacodaptes and Apheliscus , and a European genus, Epapheliscus . The single species of Epapheliscus , E. italicus , is known only from its holotype, a maxilla from the late Eocene or early Oligocene of Italy ( Dal Piaz 1930). Van Valen (1966) lists the type specimen as MGP 6834, and describes it as a maxilla with P4–M3. MGP 6834 is actually a maxilla with only P3 and is the type of? Dyspterna helbingi Dal Piaz, 1930 . The maxilla with P4– M3 to which Van Valen is clearly referring is unnumbered and was initially identified as cf. Dyspterna woodi ( Dal Piaz 1930) . This specimen (MGP unnumbered) and not MGP 6834 is actually the type of E. italicus . Based on Dal Piaz’s (1930) illustrations, Epapheliscus italicus differs from other apheliscines in several respects, including its retention of strong internal conular cristae and its complete lack of a protocone on P4. As we have not seen the original specimen, it would be premature to completely dismiss a relationship to apheliscines. Other taxa, including artiodactyls, amphilemurid erinaceomorphs, and primates, are not dissimilar; a relationship to one of these groups would make considerably more temporal and biogeographic sense.

Phenacodaptes is represented by a single late Tiffanian species, Phenacodaptes sabulosus ( Jepsen 1930; Rose 1981; Winterfeld 1982). Apheliscus includes the Clarkforkian Apheliscus nitidus ( Simpson 1937b; Rose 1981) and at least three Wasatchian species ( Cope 1874; Matthew 1918; McKenna 1960; Delson 1971; Bown 1979; Rose 1981; Gingerich 1994; Penkrot 2002). Rose (1981) discussed nomenclatural problems within the genus. He noted that intermediate forms blur the distinction between Apheliscus and Phenacodaptes , a possibility also raised by McKenna (1980). Van Valen (1967) described a new apheliscine genus, Parapheliscus , and two new species, P. bjorni and P. wapitiensis , but Delson (1971) demonstrated that the type specimen of P. bjorni is referable to Phenacolemur and considered P. wapitiensis a junior synonym of Apheliscus nitidus . Rose (1981) suggested that A. wapitiensis may be valid but, in any case, Parapheliscus is not. Gingerich (1994) revalidated A. wapitiensis as a rare, small species of the genus and established a new species, A. chydaeus , for larger early Wasatchian Apheliscus that is nevertheless still smaller than both Clarkforkian A. nitidus and later Wasatchian A. insidiosus .