Un nuevo Notungulado Hipsodonte (Hegetotheriidae, Pachyrukhinae) del Mioceno tardío de la Cordillera Oriental, provincia de Salta, Noroeste de Argentina.

Marcelo Alfredo Reguero,Claudia I Galli,Ricardo Bonini,Damian Voglino,Adriana M Candela

doi:10.5027/andgeov42n1-a04

Abstract

Late Miocene fluvial strata of the Palo Pintado Formation are broadly exposed to the northwest of the town of Angastaco, Salta province, Northwest of Argentina. These strata accumulated in the extensional Angastaco Basin. Recent field work at the Palo Pintado Formation (late Miocene), Valle Calchaqui, Salta province, Argentina has provided fossil remains that greatly increased the knowledge of the faunal assemblage of this site. A number of notoungulates and rodents were collected. A partial left jaw was collected at Quebrada Penas Blancas along the west bank of the Rio Calchaqui. Morphological and morphometric comparisons permit referral of this specimen to a new species of hegetotheriid notoungulate Paedotherium kakai sp. nov. It represents the first report of Paedotherium for the Eastern Cordillera and one of the few well-documented occurrences of this genus outside of middle-high latitudes Argentina. The widespread geographic range of Paedotherium, combined with its restricted temporal range, suggest it may be one of the most useful biostratigraphic indicator taxa for Neogene faunas. Paedotherium kakai would have been a mixed feeder that lived in gallery forests, feeding close to water bodies of a system river and lagoons, in food plains developed under humid and subtropical climate.

Highlights

Study of Neogene South American fossil mammals has traditionally focused on faunas from the middle-high latitudes in Argentina (Patterson and Pascual, 1972; Simpson, 1980; Cione and Tonni, 1995)
Recent field work at the Palo Pintado Formation, Valle Calchaquí, Salta province, Argentina has provided fossil remains that greatly increased the knowledge of the faunal assemblage of this site
Fossil mammals previously collected from the lower levels within the Palo Pintado Formation near Calchaquí River indicate a late Miocene to early Pliocene age and palaeoenvironments characterized by relative humidity (Marshall et al, 1983; Anzótegui, 1998; Starck and Anzótegui, 2001)

Summary

Introduction

Study of Neogene South American fossil mammals has traditionally focused on faunas from the middle-high latitudes in Argentina (Patterson and Pascual, 1972; Simpson, 1980; Cione and Tonni, 1995). Voglino) collected a small fossil mandible of a pachyrukhine (Notoungulata: Hegetotheriidae) from the upper levels of the Palo Pintado Formation at Quebrada Peñas Blancas in the area of Angastaco, Salta province (Fig. 1). The hegetotheriids become abundant during the late Oligocene Deseadan SALMA (Loomis, 1914; Simpson, 1945) They are last recorded in the Pleistocene of Argentina (Cerdeño and Bond, 1998). Is described a new species of Paedotherium from the late Miocene Palo Pintado Formation, Salta province, Argentina. The presence of a hypsodont fossil ungulate species in a forested environment is discussed

Materials and methods

Geographic and geologic setting

Systematic paleontology

Biostratigraphic and biogeographic significance of the genus Paedotherium