Revisión de Kunsia (Rodentia, Cricetidae): límites genéricos y específicos

PARDIÑAS, U.F.J.; D'ELÍA, G.; TETA, P.

Praia Formosa, Aracruz, Brasil

Congreso; III Congresso Brasileiro de Mastozoologia; 2005

A preliminary revision of Kunsia Hershkovitz, 1966 was made studying almost all the available specimens including type material for (in order of nomination) Mus principalis Lund, Scapteromys fronto Winge, S. gnambiquaræ M. Ribeiro, S. chacoensis Gyldenstolpe, and Kunsia fronto planaltensis Avila-Pires. A new genus is proposed to allocate K. fronto and their subspecies. In addition, the latter are newly described and planaltensis ranked as full species. The new genus is characterized by a unique combination of traits, including among others: large size, short tail (ca. 55% of combined head and body length), hispid dorsal hair, small tail scales covered by 3 hairs each one, rounded medium-size ears, pes and manus unicolored, large nasals with acuminate posterior end reaching lacrimal level, distinctive jugal enlargement, large incisive foramina reaching first upper molar protocone, denticulate coronal suture open U-shaped, carotid circulatory pattern type 1, conspicuous coronal hypsodonty, developed mesolophids and protolophids + protoconulids in both first and second lower molars, first lower molar three rooted. Morphological comparisons of the new genus with Kunsia stricto sensu (restricted here to K. tomentosus and K. principalis) and Scapteromys (including S. aquaticus and S. tumidus) provide a basis for preliminary inferences about phylogenetic relationships. The fossil occurrences of Kunsia (beside those from Lagoa Santa area, Brazil) are briefly addressed after a new study of the original remains (from Bolivia and Argentina) concluding that they not belong to the genus Kunsia or the new genus here propossed. The new genus is restricted to three recording localities (one exclusively fossil) in Brazil and one in Argentina and has an unique record (Planaltina, Brasil) in the last four decades. Field work is urgently needed to assess the conservation status of these peculiar sigmodontine rodents.