NEW MAMMAL FAUNAL DATA FROM CERDAS, BOLIVIA, A MIDDLE-LATITUDE NEOTROPICAL SITE THAT CHRONICLES THE END OF THE MIDDLE MIOCENE CLIMATIC OPTIMUM IN SOUTH AMERICA

CROFT, D.; CARLINI, A.A.; CIANCIO, M.R.; BRANDONI, D.; DREW, N.; ENGELMAN, R.K.; ANAYA, F.

JOURNAL OF VERTEBRATE PALEONTOLOGY

SOC VERTEBRATE PALEONTOLOGY

Lugar: Lawrence; Año: 2016 vol. 2016 p. 1 - 17

0272-4634

We provide new and revised identifications of mammals from the early middle Miocene (Langhian age,Colloncuran South American Land Mammal Age [SALMA]) of Cerdas, Bolivia. We also formally name a new typotherenotoungulate, Hegetotherium cerdasensis, sp. nov., that can be distinguished by the absence of an external talonid sulcus onm3 and its small size (15?25% smaller than Hegetotherium mirabile). We refer several typothere specimens from Nazareno,Bolivia, to H. cerdasensis, which suggests that the two sites are of similar age. We report the first sparassodont andastrapothere remains from Cerdas. Sparassodont remains include an associated basicranium and mostly complete mandible;the species appears to represent a new, small-bodied borhyaenoid. Astrapothere remains consist of many tooth fragmentsfrom a new species of the subfamily Uruguaytheriinae. A partial sloth dentary from Cerdas likely pertains to the subfamilyMegatheriinae and is the first report of the family Megatheriidae from the site. A newly discovered peltephilid armadillospecimen includes a partial articulated carapace that supports recognition of the Cerdas taxon as a new species. The twodasypodids of Cerdas (one Euphractini, one Eutatini) represent two new species closely related to undescribed species fromthe late middle Miocene (Serravallian age, Laventan SALMA) of Quebrada Honda, Bolivia. The mammals of Cerdasindicate that (1) the middle latitudes (southern tropics) contributed significantly to the diversity of Miocene mammalcommunities in South America; and (2) the Middle Miocene Climatic Optimum was a key factor in the differentiation ofSouth American mammal assemblages.