New cranio-dental remains of Nothrotheriinae (Mammalia, Xenarthra, Folivora) from the Late Miocene of Central Argentina

Abstract

Among extinct sloths, Nothrotheriidae nothrotheriines are characterised by caniniforms (when present) separated by a diastema from the molariform tooth row and quadrangular, rectangular or trapezoidal molariforms with longitudinal grooves on the lingual and labial surfaces. The subfamily Nothrotheriinae is recorded from the Middle Miocene of Bolivia and Argentina to the Pleistocene of different regions of South America, Central America and North America. Neogene well-known representatives include Pronothrotherium, Huilabradys, Mionothropus, Aymaratherium, Lakukullus and the recently defined genus Mcdonaldocnus, whose remains were found from Argentina, Colombia, Uruguay, Peru, Brazil and Bolivia. Mcdonaldocnus includes materials from Argentina and Bolivia previously assigned as ‘Xyophorus’. New records from Late Miocene levels of the Cerro Azul Formation cropping out in the Chasicó creek locality, Buenos Aires Province, and in the localities of Telén and Loventué, La Pampa Province, allow us to describe cranio-dental remains of Nothrotheriinae Mcdonaldocnus bondesioi and Mcdonaldocnus sp., respectively. The identification of Mcdonaldocnus sp. in the Cerro Azul Formation at La Pampa Province constitutes the first record of Nothrotheriinae for this province.