INVESTIGADORES
SCANFERLA Carlos Agustin
congresos y reuniones científicas
Título:
A complete skeleton of an abelisaurid theropod from the Late Cretaceous of patagonia, Argentina
Autor/es:
JUAN IGNACIO CANALE; FERNANDO NOVAS; CARLOS AGUSTÍN SCANFERLA
Lugar:
San Juan
Reunión:
Jornada; Jornadas Argentinas de Paleontología de Vertebrados; 2006
Resumen:
A
joint exploration of the Museo "Ernesto Bachmann" of Villa El Chocon
(Neuquen) and Museo Argentino de Ciencias Naturales (Buenos Aires) resulted in
the discovery of beautifully articulated skeleton of an apparently new
abelisaurid theropod. This material constitutes the best preserved of the
oldest known abelisaurids from Gondwana. The skeleton was excavated from levels
of the Huincul Formation (Turonian-Santonian) in only one big plaster jacket,
weighting approximately 6 tons. The skeleton, depicting an opistothonic
position, preserves valuable anatomical details, especially regarding with
skull and jaws. The specimen (MMCH-FV 49) measures around 6 meters long, and
exhibits abelisaurid features. The hypertrophied cervical epipophyses of the
new abelisaurid lack the cranial projections that characterize Noasaurus,
Aucasaurus and Carnotaurus. Furthermore, the jaw exhibits wide
contacts between dentary and postdentary bones, a condition that is interpreted
as less derived than that of Carnotaurus and Majungasaurus. The
dorsal border of ilium is convex, not straight as in Carnotaurinii.
Interestingly, the new abelisaurid lacks of frontal horns, retaining simple albeit
thickned, supraorbital margins. Also recorded from beds of the Huincul Fm. is
the basal abelisaurid llokelesia aguadagrandensis Coria y Salgado, which
distinguishes from the new abelisaurid in the more primitive condition of the
postorbital bone (which is slightly expanded distally), the poorly defined
diapo-postzygapophysial laminae of cervical vertebrae, as well as in the
laterally directed transverse process of the middle caudal vertebrae, different
from the latero-posteriorly directed transverse process in the new material.
The underlying Candeleros Fm. has yielded the remains of the basal abelisaurid Ekrixinatosaurus
novasi Calvo el al., distinguishable from the new material by its
longer and less inclined contact between jugal and maxilla, and anterior
trochanter of femur more cranially projected. Available evidence indicate that
basal abelisaurids were abundant and diverse during Turonian to Santonian
times, playing the role of medium-sized
predators alongside with the big carcharodontosaurids which occupied the role
of top predators.