New records of Neogene Xenarthra (Mammalia) from eastern Puna (Argentina): diversity and biochronology

QUIÑONES, SOFÍA I.; MIÑO-BOILINI, ÁNGEL R.; ZURITA, ALFREDO E.; CONTRERAS, SILVINA A.; LUNA, CARLOS A.; CANDELA, ADRIANA M.; CAMACHO, MARÍA; ERCOLI, MARCOS D.; SOLÍS, NATALIA; BRANDONI, DIEGO

JOURNAL OF PALEONTOLOGY

PALEONTOLOGICAL SOC INC

Año: 2019 vol. 93 p. 1258 - 1275

0022-3360

Xenarthra is an endemic South American lineage of mammals, probably the sister clade of the other placentalmammals. The oldest records of Xenarthra are from the latest Paleocene, although its current diversity is much lower thanthat recorded in some intervals of the Cenozoic Era. A new Neogene Xenarthra (Pilosa and Cingulata) assemblage fromtwo localities of the Argentine Eastern Puna (Calahoyo and Casira) is described. The newly recorded taxa?Cingulata,Dasypodidae, Eutatini: Stenotatus sp. indet. and Eutatini indet., Euphractini: Macrochorobates scalabrinii (Moreno andMercerat, 1891), and Tardigrada, Mylodontinae: cf. Simomylodon sp. indet. and Simomylodon cf. S. uccasamamensisSaint-André et al., 2010?and those already published from Calahoyo?Cingulata: Macrochorobates chapadmalensis(Ameghino, 1908), Eosclerocalyptus sp. indet., and Tardigrada, Megatheriidae: Pyramiodontherium bergi (Morenoand Mercerat, 1891)?suggest a middle?late Miocene age for the fossil-bearing levels. In Calahoyo, the presence ofStenotatus sp. indet., in addition to some rodents currently under study in the lower levels, suggest a closer similaritywith the palaeofauna of Cerdas (southern Bolivia), probably involving the last part of the Miocene Climatic Optimum.The Xenarthra recorded in the middle and upper levels of Calahoyo and Casira suggest a late Miocene?Pliocene age.A comparative analysis between Calahoyo and Casira highlights the absence of Cingulata in the latter and a high diversityin the former. This situation probably indicates different paleoenvironmental conditions. Finally, we present the first certainrecord of the genus Simomylodon Saint-André et al., 2010 in Argentina, which includes the oldest record of dermalossicles for sloths in South America.