NOTOPTERNA: UN NUEVO ORDEN DE MAMIFEROS UNGULADOS EOGENOS DE AMERICA DEL SUR. PARTE I. LOS AMILNEDWARDSIDAE

Miguel F. Soria

Abstract


The Order Notoptema, recognized by Soria (1984 b), is characterized as follows: brachyodonty; strong tendency toward molarization of premolars; M1-3 bear a strong resemblance to various Paleocene- Eocene notoungulates, (for instance presence of parastyle, labial fossetes, etc.); M1-3 are selenodont, bicrescentic, resembling litopterns; the ear region exhibits certain peculiarities like a great petrosus. This paper (part 1) deals with the most primitive Notopterna, the Amilnedwardsidae Soria, 1984 a. Amilnedwardsia brevicula Ameghino, 1901, A. acutidens (Ameghino, 1901) and Rutimeyeria conulifera Ameghino, 1901, are redescribed. The family Amilnedwardsidae shows close affinities with the family Indalecidae Bond and Vucetich, 1983, such that A, acutidens may be considered a structural ancestor of lndalecia grandensis. Comparisons with the main groups of Tertiary South American ungulates were made, and homoplasies were determined on the recognition of correlated transformation series of characters. Probable ancestors were examined, and it was concluded that the origin of the Amilnedwardsidae, and thus of the Notoptema, is independet of that of other orders of Tertiary South American ungulates. The inclusion of the Notopternain any other order currently recognized would render them diphyletic. The Notopterna is included as incertae sedis within superorder Meridiungulata (sensu Soria, 1989).

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