New endemic Dasypodidae (Xenarthra, Cingulata) from the Late Miocene of Ecuador and the importance of the tropics in the cladogenesis of armadillos

The fossil remains here studied include several osteoderms from the dorsal carapace of a Dasypodinae armadillo, recovered from the Letrero Formation (c. 9 Ma) in the area of Nabón, southern Ecuador, by an interdisciplinary team from the Escuela Politécnica de Quito (Ecuador) and CONICET (Argentina). The unique combination of characters observed in this new material indicates the existence of a new genus and species. Such features include large dorsal foramina restricted to mobile osteoderms probably related to a highly developed glandular system; serrated borders of the articular portion of mobile osteoderms; and rectangular fixed osteoderms with a poorly defined ornamentation pattern including long and narrow central figures. The cladistic analysis performed in this study recovers the new genus as the sister group to a clade of late-diverging dasypodines and Plesiodasypus colombianus as the most basal Dasypodinae. This result is morphologically supported by the very different morphologies of both fixed and mobile osteoderms of Plesiodasypus and Anadasypus, compared to the analysed taxon. Interestingly, a similar diversity pattern is recorded for the Middle Miocene of La Venta, where two very divergent genera co-occur at the same locality. This new endemic armadillo from Ecuador increases the paleontological knowledge of the Neogene at lower latitudes in South America while revealing a complex early evolutionary history of Dasypodinae in the tropics. Also, it provides new data on the hypothesis of provincialism of the faunas of Nabón. https://zoobank.org/urn:lsid:zoobank.org:pub:1EF486CE-9D7C-47EF-8E4F-DFD83969921F