A new derived abelisaurid from the Bajo de la Carpa Formation, Late Cretaceous of the Neuquen Basin, Neuquen Province, Argentina
Publicado por Leonardo Filippi en 16:59
L.S. Filippi1,
R.D. Juarez Valieri2 y C.A. Garrido3
We report a new abelisaurid theropod specimen,
which represent the most complete abelisaurid theropod skeleton yet reported
from the Bajo de La Carpa Formation. It comes from the La Invernada area,
located 50 kilometers south from Rincón de los Sauces, Neuquén Province. The
partially excavated material is well preserved and display scarce signs of
deformation. The pieces recovered comprises a partial skull with complete
basicranium, both frontals, postorbitals and squamosals, four cervical
vertebrae including atlas, eight dorsals and eigth caudals, cervical and dorsal
ribs, an haemal arch, and indeterminate pieces. The frontals are flat, opposite
to the condition present in Abelisaurus,
Aucasaurus and Carnotaurus. The postorbitals present slightly convex and
ornamented dorsal margins, in contrast to Ekrixinatosaurus
and Skorpiovenator. The jugal process
of the postorbitals is anteriorly recurved thus enclosing the orbit, a
character proposed as autapomorphic of Brachyrostra. The cervical vertebrae show
anterior processes on the epipophysis and reduced neural spines as in Carnotaurus. The anterior and middle
caudal vertebrae are tipical of derived abelisaurids, with strong centrodiapophyseal
laminae and with laterodorsally projected and distally expanded transverse
processes. Is evident the presence of hyposphene-hypantrum in the anterior
caudals as in Aucasaurus and Carnotaurus, but it appear absent in the
preserved middle caudals, similar to Ilokelesia.
This new specimen is relevant both anatomically and phylogenetically, contributing
to the knowledge of the abelisaurid theropods, and increasing the diversity of
the Cretaceous vertebrates from the Bajo de la Carpa Formation.
1 Museo Municipal Argentino Urquiza.
Jujuy y Chaco s/n, 8319, Rincón de los Sauces, Neuquén, Argentina.
2 Secretaría de Cultura de la Provincia de Río
Negro, 8332 General Roca, Río Negro, Argentina.
3 Museo Provincial de Ciencias Naturales Prof.
Dr. Juan Olsacher, Dirección Provincial de Minería. Etcheluz y Ejército
Argentino, 8340, Zapala, Neuquén, Argentina.
Resumenes XXVIII Jornadas Argentinas de Paleontología de Vertebrados, Zapala-Chocón, Neuquén, Argentina. 21 al 23 de Mayo del 2014.
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