THE FIRST PLIOCENE MAMMALS FROM THE NORTHEAST (MESOPOTAMIA) OF

CANDELA, A.M., NORIEGA, J.I, Y REGUERO, M.

JOURNAL OF VERTEBRATE PALEONTOLOGY

Society of Vertebrate Paleontology

Año: 2007 vol. 27 p. 476 - 483

0272-4634

ABSTRACT (nota: para abir la prueba de imprenta adjunta más abajo, la clave es 2005-0120—The record of Neogene faunas from the northeast of Argentina (Mesopotamia) is sporadic; whereas, thelate Miocene vertebrate-bearing horizons in this area contain a very abundant and diverse fauna, the Pliocene deposits are poorly known and have been unfossiliferous until now. This situation makes the understanding of the biogeographic and evolutionary history of the Mesopotamian taxa difficult. In this contribution, the first mammals are described that were recovered from the most basal levels of the Punta Gorda Group (Alvear Formation) at Entre Ríos Province,assigned to the late Pliocene (Lower Matuyama) by previous paleomagnetic studies. These beds are paleomagneticallybracketed between 1.95–2.6 Ma (late Pliocene) in the Alvear section and help to refine the biostratigraphy of these specieselsewhere in northeastern Argentina. The echimyids Paramyocastor diligens (Ameghino, 1888) and Eumysops sp., andthe hegetotheriid Paedotherium cf. typicum herein reported support a Pliocene age for the sediments from which theywere recovered. These mammals suggest a paleoenvironment characterized by semiarid and open lowlands, markedlydifferent than that inferred for the Late Miocene in this area. Alvear Formation) at Entre Ríos Province,assigned to the late Pliocene (Lower Matuyama) by previous paleomagnetic studies. These beds are paleomagneticallybracketed between 1.95–2.6 Ma (late Pliocene) in the Alvear section and help to refine the biostratigraphy of these specieselsewhere in northeastern Argentina. The echimyids Paramyocastor diligens (Ameghino, 1888) and Eumysops sp., andthe hegetotheriid Paedotherium cf. typicum herein reported support a Pliocene age for the sediments from which theywere recovered. These mammals suggest a paleoenvironment characterized by semiarid and open lowlands, markedlydifferent than that inferred for the late Miocene in this area. Alvear Formation) at Entre Ríos Province,assigned to the late Pliocene (Lower Matuyama) by previous paleomagnetic studies. These beds are paleomagneticallybracketed between 1.95–2.6 Ma (late Pliocene) in the Alvear section and help to refine the biostratigraphy of these specieselsewhere in northeastern Argentina. The echimyids Paramyocastor diligens (Ameghino, 1888) and Eumysops sp., andthe hegetotheriid Paedotherium cf. typicum herein reported support a Pliocene age for the sediments from which theywere recovered. These mammals suggest a paleoenvironment characterized by semiarid and open lowlands, markedlydifferent than that inferred for the late Miocene in this area.