Basal or not basal Cingulates in the middle Miocene of Peruvian Amazonia

JULIA, TEJADA; PIERRE-OLIVIER, ANTOINE; PATRICE, BABY; FRANÇOIS, PUJOS; RODOLFO, SALAS-GISMONDI

San Juan

Congreso; IV Congreso Latinoamericano de Paleontología de Vertebrados; 2011

Cingulate fossils from the Tertiary tropical region have been changing our view of the phyletic and biogeographic history of this group. Some new Paleogene (Salas-Gismondi et al., this volume) and Neogene (Antoine et al., 2007) localities in Peruvian Amazonia have yielded important, yet fragmentary, cingulate material. Here we present the remarkable cingulate assemblage from Fitzcarrald, named from a major geomorphic feature of the Amazon basin (Espurt et al., 2007), located around 10ºS latitude, in Ucayali, Peru. This fauna is middle Miocene in age (Antoine et al., 2007) and particularly interesting because of its cingulate taxonomic diversity. Indeed, Glyptodontidae material includes at least four taxa of different evolutionary "stages" comprising basal forms like Parapropalaehoplophorus and Glyptatelinae (Glyptatelus), as well as derived ones (Glyptodontinae). The record in the middle Miocene of basal morphotypes, already extinct long ago in coeval faunas from higher latitudes, point to the continued presence of basal clades at tropical areas throughout the Tertiary. Interesting is the Fitzcarrald record of Pachyarmatherium, a genus so far reported from the Plio-Pleistocene of USA (Downing & White, 1995), and Pleistocene of South America (e.g., Porpino et al., 2009; Rincón & White, 2007). This new record therefore widely predates the previous FAD of this controversial genus, and establishes temporal concurrence with Neoglyptatelus, a genus suggested as junior synonym (e.g., Vizcaíno et al., 2003). Some questions - rather than answers - arise at this point. If we consider that tropical areas represent the center of cingulates radiation, as already proposed by other authors (e.g., Carlini et al., 1997), then, it is valid to question whether plesiomorphic character states, usually based on high latitude cingulates forms, are really primitive. Given the fact that both "basal" and "derived" morphotypes are shown to be synchronous and sympatric, both states might have appeared at about the same time.