Acta Zoologica Cracoviensia, 39(1) 1996

Issue:

VOL 39(1) 1996

Keywords:

Rodents, Cricetidae, dental morphology, Ecuador, South America, late Pleistocene, Holocene

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First record of a copemyine-peromyscine cricetid (Rodentia, Mammalia) in South America: hypotheses regarding its ancestry in the Palaearctic

• Oldřich FEJFAR
• Giovanni FlCCARELLl
• Cristiana MEZZABOTTA
• Miguel MORENO ESPINOSA
• Lorenzo ROOK
• Danilo TORRE

Abstract:

Recent research in northern Ecuador (South America) has produced the first evidence of the occurrence of a copemyine-peromyscine cricetid in Late Pleistocene and Holocene deposits. Today, these forms occur only in North and Central America, and have never been reported, even in fossil faunas, in South America. This new copemyine-peromyscine form (Copemyodon ecuadorensis nov. gen et sp.) is very primitive, and resembles Copemys Wood, 1936, rather than Peromyscus Gloger, 1841. Few living species of Peromyscus (e.g., P. truei Shufeldt, 1885, and P. leucopus Rafinesque, 1818) retain such archaic characters in the occlusal pattern of molars (Fejfar et al. 1993). This record provides new evidence for the interpretation of faunal interchange between North and South America, and for the ancestry of copemyine-peromyscine cricetids in the Palearctic. Some current hypotheses are discussed.