Roedores chinchilloideos (Hystricognathi) de la Formación Pinturas, Mioceno temprano-medio de la provincia de Santa Cruz, Argentina

• Autores: Alejandro Gustavo Kramarz
• Localización: Revista del Museo Argentino de Ciencias Naturales, ISSN-e 1853-0400, ISSN 1514-5158, Vol. 4, Nº. 2, 2002, págs. 167-180
• Idioma: español
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• Resumen

  • . The chinchilloid rodents are represented in thePinturas Formation (Ameghino’s Atrapothericulan beds) by at least three species of the genus Perimys (P.intermedius sp. nov., P. erutus and Perimys sp.) and by one species of Prolagostomus. Perimysintermedius is only known from this unit. It can be distinguished from other species by having cheek teethwith narrower laminae with straight margins, wider hypoflexus and hypoflexid, lingual flexid only in m3,enamel reduced on the labial wall of the M3, completely absent on the labial wall of M1 and M2, and onthe lingual wall of the m1 and m2. Variable size of the dentition is a result of ontogeny, as in othereuhypsodont species. Based on this criterion and on morphological characters of the dentition, P. erutusAmeghino 1887 is considered as the senior synonym of the following: P. diminutus, P. reflexus, P.angulatus, P. procerus and P. scalaris. The specimens of Prolagostomus from the Pinturas Formationshow a dentition with an intermediate evolutionary condition between the Colhuehuapian and Deseadanchinchillids and the Santacrucian species of the genus Prolagostomus.