Abstract
ABSTRACT—This study describes new remains of Hegetotheriidae (Notoungulata), including a new species, from the Deseadan (late Oligocene) of Quebrada Fiera, Mendoza Province, Argentina. The assemblage is composed of four hegetotheriines, Prohegetotherium cf. P. sculptum, Prohegetotherium sp., Prohegetotherium schiaffinoi, and Prohegetotherium malalhuense, sp. nov., and the pachyrukhine Propachyrucos cf. P. simpsoni. The presence of Prosotherium cannot be totally discounted because lower molariforms are rather similar between the two pachyrukhine genera. The new species Prohegetotherium malalhuense, sp. nov., differs from all previously described hegetotheriines by having a lingually projecting, sharp parastyle and marked parastyle groove on the ectoloph of M2–3; talonid of m1–2 posterolabially projected; talonid of m3 with marked posterolabial groove; and the smaller size. Its phylogenetic affinities are not well resolved. Prohegetotherium is paraphyletic, with P. sculptum sister taxon to the remaining hegetotheres, and the new taxon more closely related to Hegetotherium mirabile than to P. schiaffinoi. The recognition of P. schiaffinoi and Prohegetotherium cf. P. sculptum emphasizes that the fauna from Quebrada Fiera shares elements with roughly contemporaneous Deseadan faunas from northern and southern latitudes, but important faunal particularities distinguish the region as well. The record of pachyrukhines at Quebrada Fiera more closely resembles Deseadan faunas in Patagonia than temporally correlative faunas from Bolivia and Uruguay, and indicates the presence of suitable habitats in mid-latitudes of Argentina for this hypselodont clade. Faunal affinities together with particular taxa from Quebrada Fiera appear to support a significant faunal provinciality in South America during the late Oligocene. http://zoobank.org/urn:lsid:zoobank.org:pub:9DF1C9A9-92ED-4C50-BB5A-738D075E5F54SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP
Highlights
Studies on Paleogene South American fossil mammals have traditionally focused on faunas from high latitudes, especially those coming from Patagonia, Argentina (Patterson and Pascual, 1972; Simpson, 1980)
Except for the new taxon and Prohegetotherium sp., the other species are known from the Deseadan of Argentina
Prohegetotherium sculptum and the pachyrukhine Propachyrucos are common in Deseadan localities of Patagonia; on the other hand, Prohegetotherium schiaffinoi is present in Uruguay and Bolivia (Reguero and Cerden~o, 2005) and was recognized in the Argentinean provinces of Corrientes and Entre Rıos
Summary
Studies on Paleogene South American fossil mammals have traditionally focused on faunas from high latitudes, especially those coming from Patagonia, Argentina (Patterson and Pascual, 1972; Simpson, 1980). Argentinean Paleogene ‘hegetotheriines’ have been referred to Prohegetotherium, a genus that occurs at La Cantera (Chubut), early Oligocene, and various Deseadan, late Oligocene, localities in Patagonia (Reguero and Prevosti, 2010); and recognized in ?early Miocene beds at Divisadero Largo, Mendoza (Lopez, 2002, 2010; Reguero and Cerden~o, 2005; Cerden~o et al, 2008). It is present in the early Oligocene (Tinguirican SALMA [South American Land Mammal Age]) of Cachapoal, Chile,. Three genera are recognized during the Paleogene: Prosotherium, Propachyrucos, and Medistylus
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