A new titanosaur specimen with highly derived skull from the Santonian of northern Patagonia, Argentina
0 comentarios Publicado por Leonardo Filippi en 12:35
Filippi, L., Juárez Valieri, R., Gallina, P., Méndez, A., Gianechini, F. y Garrido, A.
Paleontological fieldworks carried out
on upper section of the Bajo de la Carpa Formation (Santonian, Upper Cretaceous)
at La Invernada area, near Rincón de los
Sauces city (northeast Neuquén Province), result in the discovery of several
specimens of derived titanosaurs, belonging to multiple
taxa. One of them, consists of an articulated modest-sized
individual with a nearly complete skull, the axial sequence from the atlas to
the last sacral vertebrae with their respective ribs, and both ilia.This
sequence is composed by thirteen cervical, ten dorsal and six sacral vertebrae.
The skull displays a spatulate snout morphology, with a straight anterior
margin, similar to the morphology previously recognized in other titanosaurs
such as Antarctosaurus, Bonitasaura and Brasilotitan. The neurocranial morphology is highly derived
compared with other titanosaur taxa with well-known skulls such as Sarmientosaurus, Nemegtosaurus, Tapuiasaurus
and Rapetosaurus, with displaced
frontals located behind the orbits, resulting in an opposite position to the
anterior margin of the snout. The occipital condyle is not preserved, but the
location of the neurocranial elements and the atlas-axis complex (found in anatomical
position) allow to infer a nearly perpendicular position for the tooth row
respect to the cervical sequence. This particular condition, confirmed for
first time in a derived titanosaur, is morphologically convergent with derived
rebbachisaurids such as Nigersaurus.
Besides, their respective biochrons are in agreement with the paleoecological
niche replacement of the rebbachisaurids by the spatulate snouted titanosaurs
in South America, as previously suggested in the post Turonian faunal turnover.
11º Congreso de la Asociación Argentina de Paleontología, Gral. Roca, Río Negro, Argentina 2016.
El MAU a punto de iniciar una nueva campaña en los alrededores de Rincón de los Sauces
0 comentarios Publicado por Leonardo Filippi en 12:22
El equipo del Museo Argentino Urquiza (Rincón de los Sauces, Neuquén, Argentina) realizó trabajos preliminares en el sitio de Cañadón Mistringa, para despejar varias toneladas de roca que cubrían un ejemplar de saurópodo parcialmente recuperado. Esta tarea, llevada adelante gracias al apoyo logístico del sector de Obras Públicas de la Municipalidad de Rincón de los Sauces, permitirá agilizar notablemente los trabajos de campo. Llega la época de campañas y la posibilidad de extraer definitivamente todo el material restante de este enorme dinosaurio.
Pterosaurs are an extinct group of highly modified flying reptiles that thrived during the Mesozoic. This group has unique and remarkable skeletal adaptations to powered flight, including pneumatic bones and an elongate digit IV supporting a wing-membrane. Two major body plans have traditionally been recognized: the primitive, primarily long-tailed paraphyletic “rhamphorhynchoids” (preferably currently recognized as non-pterodactyloids) and the derived short-tailed pterodactyloids. These two groups differ considerably in their general anatomy and also exhibit a remarkably different neuroanatomy and inferred head posture, which has been linked to different lifestyles and behaviours and improved flying capabilities in these reptiles. Pterosaur neuroanatomy, is known from just a few three-dimensionally preserved braincases of non-pterodactyloids (as Rhamphorhynchidae) and pterodactyloids, between which there is a large morphological gap. Here we report on a new Jurassic pterosaur from Argentina, Allkaruen koi gen. et sp. nov., remains of which include a superbly preserved, uncrushed braincase that sheds light on the origins of the highly derived neuroanatomy of pterodactyloids and their close relatives. A µCT ray-generated virtual endocast shows that the new pterosaur exhibits a mosaic of plesiomorphic and derived traits of the inner ear and neuroanatomy that fills an important gap between those of non-monofenestratan breviquartossans (Rhamphorhynchidae) and derived pterodactyloids. These results suggest that, while modularity may play an important role at one anatomical level, at a finer level the evolution of structures within a module may follow a mosaic pattern.
(2016) A Jurassic pterosaur from Patagonia and the origin of the pterodactyloid neurocranium. PeerJ 4:e2311 https://doi.org/10.7717/peerj.2311
El pasado fin de semana, el MAU, Museo Municipal Argentino Urquiza, Rincón de los Sauces, Neuquén, Argentina, realizó la evaluación de una denuncia de hallazgo de restos fósiles en el área La Invernada. Después de transitar por un camino de muy dificil acceso, se pudo dar con el lugar exacto de donde provenian los restos recuperados. Los materiales entregados al Museo correspondían a tres de los cinco huesos metacarpianos de una pata delantera de un dinosaurio saurópodo. La evaluación realizada en el lugar permitió determinar que el resto de los huesos faltantes aún estaban in situ, los cuales se encontraban muy bien preservados y articulados con el resto de dicha pata. En futuras salidas, el resto de los huesos serán recuperados y se evaluará si puede que el resto del dinosaurio se encuentre bajo la roca.
New Megaraptoran Dinosaur (Dinosauria, Theropoda, Megaraptoridae) from Late Cretaceous of Patagonia
0 comentarios Publicado por Leonardo Filippi en 9:27
Rodolfo
A. Coria and Philip J. Currie
A skeleton discovered in the
Upper Cretaceous Sierra Barrosa Formation (Turonian-Coniacian) of Neuquén
Province, Argentina represents a new species of theropod dinosaur related to
the long snouted, highly pneumatized Megaraptoridae. The holotype specimen of Murusraptor
barrosaensis n.gen et n.sp. includes much of the skull, axial skeleton,
pelvis and tibia. Murusraptor is unique in having several diagnostic features
that include anterodorsal process of lacrimal longer than height of preorbital
process, and a thick, shelf-like thickening on the lateral surface of surangular
ventral to the groove between the anterior surangular foramen and the insert
for the uppermost intramandibular process of the dentary. Other characteristic
features of Murusraptor barrosaensis n.gen. et n. sp. include a large
mandibular fenestra, distal ends of caudal neural spines laterally thickened into
lateral knob-like processes, short ischia distally flattened and slightly
expanded dorsoventrally. Murusraptor belongs to a Patagonian radiation of
megaraptorids together with Aerosteon, Megaraptor and Orkoraptor. In spite
being immature, it is a larger but more gracile animal than existing specimens
of Megaraptor, and is comparable in size with Aerosteon and Orkoraptor. The
controversial phylogeny of the Megaraptoridae as members of the Allosauroidea
or a clade of Coelurosauria is considered analyzing two alternative data sets.
Coria RA, Currie PJ (2016) A
New Megaraptoran Dinosaur (Dinosauria, Theropoda, Megaraptoridae) from the Late
Cretaceous of Patagonia. PLoS ONE 11(7): e0157973. doi:10.1371/ journal.pone.0157973
An Unusual New Theropod with a Didactyl from Patagonia Argentina
0 comentarios Publicado por Leonardo Filippi en 9:18
Sebastián
Apesteguía, Nathan D. Smith, Rubén Juárez Valieri, Peter J. Makovicky
Late Cretaceous terrestrial
strata of the Neuquén Basin, northern Patagonia, Argentina have yielded a rich
fauna of dinosaurs and other vertebrates. The diversity of saurischian dinosaurs
is particularly high, especially in the late Cenomanian-early Turonian Huincul
Formation, which has yielded specimens of rebacchisaurid and titanosaurian
sauropods, and abelisaurid and carcharodontosaurid theropods. Continued
sampling is adding to the known vertebrate diversity of this unit.
A new, partially articulated
mid-sized theropod was found in rocks from the Huincul Formation. It exhibits a
unique combination of traits that distinguish it from other known theropods justifying
erection of a new taxon, Gualicho shinyae gen. et sp. nov. Gualicho possesses a
didactyl manus with the third digit reduced to a metacarpal splint reminiscent
of tyrannosaurids, but both phylogenetic and multivariate analyses indicate
that didactyly is convergent in these groups. Derived characters of the
scapula, femur, and fibula supports the new theropod as the sister taxon of the
nearly coeval African theropod Deltadromeus and as a neovenatorid carcharodontosaurian.
A number of these features are independently present in ceratosaurs, and
Gualicho exhibits an unusual mosaic of ceratosaurian and tetanuran
synapomorphies distributed throughout the skeleton.
Apesteguía S, Smith ND,
Juárez Valieri R, Makovicky PJ (2016) An Unusual New Theropod with a Didactyl
Manus from the Upper Cretaceous of Patagonia, Argentina. PLoS ONE 11(7):
e0157793. doi:10.1371/journal.pone.0157793
Hallan el primer dinosaurio ornitópodo del norte neuquino
0 comentarios Publicado por Leonardo Filippi en 8:51
Durante la semana pasada el equipo del MAU, Museo Municipal Argentino Urquiza de Rincón de los Sauces, Neuquén, realizó el inesperado hallazgo de los restos de un ejemplar de dinosaurio ornitópodo, el cual se encuentra en muy buen estado de preservación. Las tareas de campo permitieron recuperar los restos integrados por la porción anterior del cuerpo del animal, integrada por las últimas cervicales y las primeras siete dorsales, articuladas con sus correspondientes costillas y ambas escapulo-coracoides. Además, excepcionalmente se halló el miembro anterior derecho completo y articulado al cuerpo. Si bien se habían hallado restos en la zona de este grupo de dinosaurios ornitisquios, este es el primer ejemplar de relevancia hallado en la zona norte de la Provincia de Neuquén, por lo que permite engrosar el conocimiento de la fauna de dinosaurios de esta región. Actualmente el material esta siendo preparado en el laboratorio del Museo.
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