New findings of Neogene Xenarthra (Mammalia) from Ecuador : diversity and perspective

Abstract

The knowledge of Neogene xenarthrans in Ecuador is still poor compared to other regions of South America. Until now, the only recognized species is the Cingulata Dasypodini Anadasypus aequatorianus Carlini, Castro, Madden, and Scillato-Yané, 2013 coming from the Letrero Formation (Upper Miocene, Nabon Basin, southern Ecuador). However, some recent findings allow us to improve our knowledge about the Xenarthra diversity in the current territory of this country. The new remains are also coming from southern Ecuador, and they were exhumed from the Letrero Formation (upper Miocene) and Gonzanamá Formation (Catamayo basin, middle-upper Miocene). The recognized taxa include the Tardigrada Mylodontidae Mylodontinae, cf. Simomylodon sp., and the Cingulata Glyptodontidae indet. and Pampatheriidae. The morphology of the osteoderms and molariforms of the glyptodonts suggests that it could belong to new taxa, but further studies are necessary to confirm this taxonomic hypothesis. In turn, if confirmed, this represents the first report of the genus Simomylodon in Ecuador. A preliminary comparison with the Laventan fauna of Colombia reveals taxonomic differences. To summarize, this new findings shed light to our knowledge of the Neogene diversity of Xenarthra at low latitudes and underline the relevance of the Mio-Pliocene units. Certainly, new field works will produce more findings that help us to interpret more properly the diversity achieved by this clade, and its phylogenentic and paleobiogeographic relationship with faunas from coetaneous deposits of southern South America. *Financial support: PICT 201 7-0765, PI 0002.