Overosaurus paradasorum, a new sauropod dinosaur from Rincón de los Sauces
1 comentarios Publicado por Leonardo Filippi en 14:21
Rodolfo
A. Coria, Leonardo S. Filippi, Luis M. Chiappe, Rodolfo García y Andrea B.
Arcucci
A new lithostrotian
sauropod, the small-sized Overosaurus paradasorum n. gen et sp. from the Anacleto Formation (Cam-panian, Late Cretaceous, Neuquén Group,
Patagonia, Argentina) is here described. The specimen (MAU-Pv-CO-439) consists of a fully articulated
vertebral series from the 10th cervical to the 20th caudal vertebra, the last
cervical ribs, several dorsal ribs in articulation with their respective
vertebrae, the complete right ilium and fragments of the left ilium. Overosaurus
paradasorum is diagnosed by a unique combination of
characters that includes (1) posterior cervical vertebrae with long pre- and
postzygapophyses that project beyond the anterior and posterior borders of the
centrum, respectively, (2) postspinal lamina absent in all dorsal neural
spines, (3) wide and massive 9th and 10th caudal centra that are slightly
exca-vated laterally and have relatively flat ventral surfaces, (4) laminar
projection on the posterior border of the second and third dorsal rib, (5)
ilium proportionally shorter anteroposteriorly and taller dorsoventrally than
in other lithostrotians, and (6) the preacetabular process of the ilium
strongly deflected laterally and with a ventrolaterally tapering end. Analysis
of the phylogenetic relationships of Overosaurus places it within the Aeolosaurini,
as the sister taxon of a monophyletic group formed by Aeolosaurus rionegrinus, A. maximus, Gondwanatitan faustoi and
Pitekunsaurus
macayai. Overosaurus is a
new representative of a highly diversified assemblage of Campanian
lithostrotians from Patagonia that includes both Aeolosaurini
and saltasaurids (e.g. Saltasaurus, Neuquensaurus) this small new taxon
falls within the low end of the size spectrum represented by these Late
Cretaceous sauropods.
Coria, R. A., Filippi, L. S., Chiappe, L. M., García, R.
& Arcucci, A. B. 2013. Overosaurus
paradasorum gen. et sp. nov., a new sauropod dinosaur (Titanosauria:
Lithostrotia) from the Late Cretaceous of Neuquén, Patagonia, Argentina. Zootaxa 3683 (4): 357-376.
Ariana Paulina Carabajal,
Juliana Sterli, Johannes Müller y André Hilger
Turtles are one
of the least explored clades regarding endocranial anatomy with few available
descriptions of the brain and inner ear of extant representatives. In addition,
the paleoneurology of extinct turtles is poorly known and based on only a few
natural cranial endocasts. The main goal of this study is to provide for the
first time a detailed description of the neuroanatomy of an extinct turtle, the
Late Jurassic Plesiochelys etalloni, including internal carotid circulation,
cranial endocast and inner ear, based on the first digital 3D reconstruction
using micro CT scans. The general shape of the cranial endocast of P. etalloni
is tubular, with poorly marked cephalic and pontine flexures. Anteriorly,
the olfactory bulbs are clearly differentiated suggesting larger bulbs than in
any other described extinct or extant turtle, and indicating a higher capacity
of olfaction in this taxon. The morphology of the inner ear of P. etalloni
is comparable to that of extant turtles and resembles those of slow-moving terrestrial
vertebrates, with markedly low, short and robust semicircular canals, and a
reduced lagena. In P. etalloni the arterial pattern is similar to that
found in extant cryptodires, where all the internal carotid branches are
protected by bone. As the knowledge of paleoneurology in turtles is scarce and
the application of modern techniques such as 3D reconstructions based on CT
scans is almost unexplored in this clade, we hope this paper will trigger
similar investigations of this type in other turtle taxa.
Carabajal AP, Sterli J, Müller J,
Hilger A (2013) Neuroanatomy of the Marine Jurassic Turtle Plesiochelys
etalloni (Testudinata, Plesiochelyidae). PLoS ONE 8(7): e69264.
doi:10.1371/journal.pone.0069264
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