Producción CyT
Congreso
Autoría
Schubert B.W.
;
Chatters, JC
;
Arroyo Cabrales, J
;
SOIBELZON, LEOPOLDO HECTOR
;
Griffith, CS
;
De Anda, G
;
Luna Herrera, P
Fecha
2016
Editorial y Lugar de Edición
Society of Vertebrate Paleontology
Resumen
Información suministrada por el agente en
SIGEVA
Short-faced bears (Subfamily Tremarctinae) are a group of American ursids that are mostly extinct. The earliest member of the group, Plionarctos, appears in the latest Miocene of North America and disappears by the middle Pliocene. Tremarctos emerges in the Pliocene and is best represented in the southeastern United States from the Pleistocene. Tremarctos ornatus is the only extant tremarctine, and is currently restricted to South America. The fossil record of T. ornatus is sparse, and isn?t kn...
Short-faced bears (Subfamily Tremarctinae) are a group of American ursids that are mostly extinct. The earliest member of the group, Plionarctos, appears in the latest Miocene of North America and disappears by the middle Pliocene. Tremarctos emerges in the Pliocene and is best represented in the southeastern United States from the Pleistocene. Tremarctos ornatus is the only extant tremarctine, and is currently restricted to South America. The fossil record of T. ornatus is sparse, and isn?t known until the Holocene. Arctodus first occurs in the late Pliocene of North America and by the middle Pleistocene was represented by A. simus, an exceedingly large bear that occurred across the continent. The genus Arctotherium appears in South America in the early Pleistocene, and in contrast to the evolutionary trajectory of Arctodus, the earliest Arctotherium species (A. angustidens) was the largest, and the terminal Pleistocene species (A. wingei) was diminutive. Here we add to the understanding of tremarctines by describing the first records of Arctotherium outside South America. These specimens are from the Yucatán Peninsula, and are recorded from three cave sites. This includes a partial right maxilla with M1 and M2 from Actun Halal, Cayo District, Belize, and two underwater sites from Mexico that have multiple individual skeletons preserved. One of these caves, Hoyo Negro from Quintana Roo, has at least six skeletons and some material has been collected. This includes complete crania from an adult and subadult, as well as dentaries and cervical vertebrae from the subadult. The adult skull has been radiocarbon dated as latest Pleistocene, and is similar in age to other large mammals from the site, including an early human (Homo sapiens) partial skeleton (known as ?Naia?). The bear material analyzed from Hoyo Negro represents the most complete examples of Arctotherium skulls from the late Pleistocene, and together with the material still in the underwater caves, represents the most complete fossil skeletons known for the entire subfamily, from Miocene through Pleistocene. The occurrence of Arctotherium in the Yucatán indicates a range extension for the genus of at least 1500 km outside South America, and demonstrates our limited knowledge of late Pleistocene communities of this region. The relative absence of Tremarctos and other bears in South America during the Pleistocene may be a reflection of Arctotherium filling the bear niche throughout Central America until their extinction in the latest Pleistocene or early Holocene.
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Palabras Clave
biogeographyMéxicoArctotherium