INVESTIGADORES
CARLINI Alfredo Armando
congresos y reuniones científicas
Título:
Preliminary Report Of Deseadan Sloths From Quebrada Fiera (Mendoza Province, Argentina).
Autor/es:
PUJOS F., CARLINI A. A., CERDEÑO E. Y PRÁMPARO M. B
Lugar:
NEUQUÉN
Reunión:
Congreso; III Congreso Latinoamericano de Paleontología de Vertebrados; 2008
Resumen:
Deseadan SALMA (29-24,5 My) is a key period in South American mammal
evolution, with the appearance of primates, the diversification of rodents and the establishing
of sloths (Tardigrada). Sloths appear at least during the early Oligocene (McKenna et al.,
2006) and begin to be abundant and diversified during the late Oligocene (Pujos & De Iuliis,
2007). The Pyrotherium fauna was identified by Ameghino (1895) in the La Flecha site
(Santa Cruz Province) and defined as Deseadan SALMA by Pascual et al. (1965). Traditional
Deseadan localities are situated in Patagonia (e.g., La Flecha and Cabeza Blanca) and the
Bolivian Altiplano (Salla and Lacayani). Recently, new Deseadan localities have been
identified in Uruguay and Argentina (Fray Bentos) and Peru (Moquegua). Currently, four sloth
clades are generally recognized: Mylodontidae, Megatheriidae, Megalonychidae, and
Nothrotheriidae. Later Engelmann (1987) described Pseudoglyptodon from Salla, a sloth with
glyptodontoid teeth. More recently, Carlini & Scillato-Yané (2004) and Pujos & De Iuliis
(2007) described some megalonychid and mylodontoid (Orophodontidae) sloths from La
Flecha and Salla, respectively. The fauna from Quebrada Fiera in Mendoza Province (centralwestern
Argentina) was noted by Gorroño et al. (1979) and listed by Pascual and de la Fuente
(1993). Recent paleontological campaigns lead by A.A.C. (1996), M.B.P. and E.C. (2006-
2008) recovered several remains of basal sloths and Cingulata. Among them, Mylodontoid
sloths are the most abundant, and the most complete remain is a humerus. This specimen is
short, massive, anteroposteriorly compressed with a strong medial epicondyle and an
entepicondylar crest. The tubercles are huge and the deltopectoral crest extends distally from
the massive greater tubercle beyond the half of the diaphysis. Megalonychidae are represented
by a small anterior spout of a dentary. Several humerus, tibia and carpal-tarsal bone
fragments complete the Tardigrada remains. The study of sloth remains from Quebrada Fiera
will allow: 1/ enhancing our knowledge of basal megalonychid and mylodontid sloths, 2/
testing the monophyly of the orophodontoids and their relationship with other mylodontoid
sloths, 3/ establishing a possible correlation of central (Bolivia) and southern (Patagonia,
Argentina) South American Deseadan sloth faunas. It will also shed light on the basal
dispersion of major sloths clades and perhaps also on the origin of Tardigrada.