A singular Hegetotheriinae (Notoungulata, Typotheria) from the late Oligocene-Early Miocene of the Subandean Region of Bolivia

Autor: Marcelo Alfredo Reguero, David Eric Tineo, Paula Bona, Leandro Martín Pérez, Gustavo Dardo Vergani, Gloria González Ruiz, Daniel Gustavo Poiré
Jazyk: English<br />Spanish; Castilian<br />French<br />Portuguese
Rok vydání: 2021
Předmět:
Zdroj: Brazilian Journal of Geology, Vol 51, Iss 2 (2021)
Druh dokumentu: article
ISSN: 2317-4692
2317-4889
DOI: 10.1590/2317-4889202120200067
Popis: Abstract Geological studies in the northern sector of the Chaco foreland Basin, Bolivia, yielded new fossils coming from late Oligocene-late Miocene of the Petaca Formation. Few fossil mammals were known from the Subandean Region of Bolivia. We report a partially complete mandible of a hegetotheriid Hegetotheriinae (Notoungulata, Typotheria) from Abapó (Río Grande River). The specimen (YPFB-LIT-PAL-005) is very close in size and dental morphology to the late Oligocene (Deseadan South American Land Mammal Age, SALMA) — Santacrucian (early Miocene) Prohegetotherium schiaffinoi (Kraglievich 1932) from Fray Bentos (Uruguay and Argentina), Salla (Bolivia), Divisadero Largo-Potrerillos and Quebrada Fiera (Argentina). However, mandibular characteristics, as the shape with a marked change in height along its length, increasing towards the back, a prominent masseteric crest, a deep mandibular groove, and a remarkable thickening of the ventral rim of the mandible, indicate differences between this specimen and Prohegetotherium schiaffinoi and the other Hegetotheriinae. The affinity of YPFB-LIT-PAL-005 with P. schiaffinoi suggests a late Oligocene to early Miocene for the upper bearing horizon of the Petaca Formation (in Abapó), an older age than previously assigned to the top of this unit (late Miocene), and confirms the taxon distribution between ∼ 36 ° to ∼ 17 ° south latitude.
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