9-3-2011 - En una cantera del estado de Utah, en Estados Unidos, se ha descubierto un nuevo género de dinosaurio del grupo de los saurópodos con su característico cuello largo.
El animal habría tenido una impresionante musculatura del muslo lo que hace creer a los científicos que las patas traseras habrían podido ser utilizadas por el dinosaurio para defenderse de otros animales, además de resultar muy útiles para desplazarse por terrenos abruptos. Debido a estas características ha sido bautizado como Brontomerus o “muslo de trueno“.
Los científicos británicos y estadounidenses que lo han descubierto han identificado fósiles de dos ejemplares, uno mayor, como del tamaño de un elefante grande, y uno mucho más pequeño, un juvenil por lo que podrían ser una madre y su cría pero esto es solo una conjetura. Mientras que el ejemplar grande tendría unas dimensiones de unos 14 metros de largo y pesaría unas seis toneladas el pequeño mediría entorno los 4,5 metros de longitud y los 200 kilogramos de peso.
Aunque no han aparecido esqueletos completos, sí que ha aparecido el suficiente número de piezas para estimar cómo sería el animal. Una de las piezas claves es el hueso de la cadera que, debido al gran tamaño, ha abierto la suposición de que sería para sujetar los grandes músculos de los muslos, seguramente los más grandes que se conocen dentro del grupo de los saurópodos.
Michael P. Taylor de la University College de Londres y líder del estudio que se publica en la revista Acta Palaeontologica Polonica “Cuando identificamos la forma de la cadera nos preguntamos para qué serviría y llegamos a la conclusión de que, seguramente, sería muy útil para dar patadas“.
Otro de los científicos del equipo, Matt Wedel, de la Western University de Pomoma, California, afirma que es “el saurópodo más atlético” y argumenta que como los saurópodos preferían áreas más secas y elevadas, a lo mejor “el Brontomerus vivía en un terreno accidentado y sus musculosas patas eran también algo así como la tracción 4×4 del dinosaurio“.
Los restos son de hace 110 millones de años y aunque los descubrieron en los años noventa, en un yacimiento saqueado por traficantes de fósiles, los llevaron al Museo Natural de Oklahoma, dejándolos por olvidados allí. Hasta que en 2007, Michael Taylor decidió ahondar en el estudio de esos fósiles descubriendo así que pertenecían a un dinosaurio desconocido por la Ciencia.
http://www.campodemarte.com/descubierto-un-nuevo-tipo-de-dinosaurio.html
Michael P. Taylor of the University College London who led the study published in the journal Acta Palaeontologica Polonica "When we identify how hip we wonder what it would and we conclude that, surely, would be very useful for kicking" .
Brontomerus mcintoshi ha sido identificado como un Camarasauromorpha de incierta posición en los clados.
Se han descrito 5 en este animal autopomorfías entre las que destacan: la presencia de un lóbulo preacetabular del 55% de la longitud total del ilion, más largo que en cualquier otro saurópodo y el hecho de que esté dirigido anterolateralmente 30º con respecto al plano sagital.
La gran longitud de el lóbulo preacetabular da a entender la existiencia de unos poderosos músculos protractores y abductores, cuya interpretación precisa no puede ser realizada dada la ausencia elementos con los que estarían relacionados, como el fémur o las vértebras caudales. (No obstante es fácil encontrar reconstrucciones de B mcintoshi en una utilizando esta característica a modo defensa contra los depredadores, personalmente me parece aventurarse demasiado ver a este animal propinando sus potentes patadas a depredadores como Utahraptor)
Aunque reconozco que no es tan espectacular desde el punto de vista del sensacionalismo, considero más notable el hecho de que es el octavo género de saurópodo en ser descrito en el Cretácico Inferior de Norteamérica y que en términos de registro fósil implica que probablemente a diferencia de lo que se creía, los saurópodos no experimentaron un brusco grado de desaparición en este lugar. De hecho concretando al final del jurásico la fauna estaría dominada por diplodócidos y en el cretácico el dominio correspondería a los macronarios (como los camarasauromorfos como B. mcintoshi), que serían más escasos pero diversos.
Y tras estas líneas acabo como no con las genuinas reconstrucciones de Brontomerus mcintoshi chutando cual jugador de fútbol al Utahraptor de turno XD:
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SYDNEY: Fossils have been found of a new dinosaur that not only had unusually large hip bones, but was likely to have had the largest leg muscles of any known member of the sauropod family, new research suggests.
Named Brontomerus mcintoshi, or ‘thunder-thighs’ after its enormously powerful thigh muscles, the dinosaur is, “part of a flood of new sauropod dinosaurs coming out of the Early Cretaceous of North America – a period that was originally thought to be devoid of sauropods”, said co-author Mathew Wedel, assistant professor of anatomy at Western University of Health Sciences in California.
“What it points out is that sauropods were globally successful for almost the entire Age of Dinosaurs,” said Wedel. “Very early in their evolution they committed to being big, and that just never stopped working for them.”
In this life restoration, the adult is shown as a mother, protecting her baby from a predator by using those powerful thigh muscles to deliver a devastating kick.
Used for kicking the raptors away
During the Early Cretaceous Period 110 million years ago, Brontomerus - a member of the long-necked sauropod group which includes Diplodocus and Brachiosaurus - probably had to contend with fierce ‘raptors’ such as Deinonychus and Utahraptor, so may have used its powerful thighs as a weapon to kick predators, or to help travel over rough, hilly terrain.
“When we recognised the weird shape of the hip, we wondered what its significance might be, but we concluded that kicking was the most likely,” said first author Mike Taylor, a researcher in the Department of Earth Sciences at University College London.
“The kick would probably have been used when two males fought over a female, but given that the mechanics were all in place it would be bizarre if it wasn't also used in predator defense.”
Specimens found of mother and offspring
The fossilised bones of two specimens of Brontomerus mcintoshi – an adult and a juvenile – were rescued from a previously looted and damaged quarry in eastern Utah by researchers from the Sam Noble Museum in Oklahoma.
The team suggest that the larger specimen could be the mother of the younger and would have weighed around 6 tonnes - about the size of a large elephant - and measured 14 m in length, the team naming it in honour of John ‘Jack’ McIntosh, a retired physicist at Wesleyan University, Connecticut, and lifelong avocational palaeontologist.
At a third of the size, the smaller specimen would have weighed about 200 kg - the size of a pony - and been 4.5 m long, according to the paper recently published in the journal Acta Palaeontologica Polonica.
http://www.cosmosmagazine.com/news/4077/new-dinosaur-had-biggest-known-hips-thighs?page=0,0
Skeletal inventory of the camarasauromorph sauropod Brontomerus mcintoshi gen. et sp. nov. from the Lower Cretaceous Cedar Mountain Formation of Utah, in left lateral view. Preserved elements are white, missing elements are reconstructed in gray. After a Camarasaurus grandis reconstruction kindly provided by Scott Hartman. Taken from Taylor et al., 2011.
Age and Distribution | | Horizon: Cedar Mountain Formation (upper part of the Ruby Ranch Member), Lower Cretaceous (Aptian - Albian), Utah, U.S.A. Locality: Hotel Mesa Quarry in Grand County, Utah, USA | |
| Classification | | Dinosauria Saurischia Sauropodomorpha Sauropoda Macronaria Camarasauromorpha
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Further Reading | Taylor, Michael P., Mathew J. Wedel and Richard L. Cifelli. 2011. Brontomerus mcintoshi, a new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA. Acta Palaeontologica Polonica 56(1):75-98. (Original description) |
A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA
MICHAEL P. TAYLOR, MATHEW J. WEDEL, and RICHARD L. CIFELLI
Taylor, M.P., Wedel, M.J., and Cifelli, R.L. 2011. A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain
Formation, Utah, USA.
Acta Palaeontologica Polonica
56 (1): 75–98.
Brontomerus mcintoshi is a new genus and species of sauropod dinosaur from the Hotel Mesa Quarry in Grand County,
Brontomerus is diagnosed by five autapomorphies of the type specimen: preacetabular lobe 55% of total ilium length, longer than in any other sauropod; preacetabular lobe directed anterolaterally at 30 to the sagittal, but straight in dorsal view and vertically oriented; postacetabular lobe reduced to near absence; ischiadic peduncle reduced to very low bulge; ilium proportionally taller than in any other sauropod, 52% as high as long. In a phylogenetic analysis,
Brontomerus was recovered as a camarasauromorph in all most parsimonious trees, but with uncertain position within that clade. The large preacetabular lobe of the ilium anchored powerful protractor and abductor muscles, but precise interpretation is impossible without functionally related elements such as femora and proximal caudal vertebrae.
Brontomerus is the eighth sauropod genus named from the Early Cretaceous of North America, and more remain to be described: North American sauropod diversity did not decline catastrophically at the end of the Jurassic as often assumed. The most striking differences between Late Jurassic and Early Cretaceous sauropod faunas in North America is that the former are abundant and dominated by diplodocids, whereas the latter are comparatively scarce— though still diverse—and dominated by macronarians.
Key words : Dinosauria, Sauropoda, Camarasauromorpha, Brontomerus, Brontomerus mcintoshi, diversity, Early Cretaceous, North America.
http://app.pan.pl/archive/published/app56/app20100073.pdf
Introduction
The record of Early Cretaceous sauropod dinosaurs in North
America was for many years poorly represented, with the
only generic names in use being Astrodon Leidy, 1865 and
Pleurocoelus Marsh, 1888, the former represented only by
teeth and often considered synonymous with the latter (e.g.,
Hatcher 1903a; Gilmore 1921; Carpenter and Tidwell 2005).
In recent years, this record has been greatly expanded and
clarified by the discovery and description of Sonorasaurus
Ratkevich, 1998; Cedarosaurus Tidwell, Carpenter, and
Brooks, 1999; Sauroposeidon Wedel, Cifelli, and Sanders,
2000a; Venenosaurus Tidwell, Carpenter, and Meyer, 2001;
Paluxysaurus Rose, 2007; and Abydosaurus Chure, Britt,
Whitlock, and Wilson, 2010. Further material, representing
yet more new sauropod taxa, is known and awaits descrip−
tion: for example, two new taxa from the Dalton Wells
Quarry, a camarasaurid and a titanosaurian (Eberth et al.
2006: 220); and a titanosaurian from the Yellow Cat Member
of the Cedar Mountain Formation represented by an articu−
lated sequence of five presacral vertebrae (Tidwell and Car−
penter 2007).
Here we describe a new sauropod taxon which further ex−
tends the record of Early Cretaceous North American sauro−
pods. The ilium and scapula of this sauropod were figured, but
not described, by Kirkland et al. (1997: 93), who considered
them as “comparable to Pleurocoelus” (at that time the only
known Early Cretaceous sauropod from North America).
Institutional abbreviations.—AMNH, American Museum of
Natural History, New York, USA; BMNH, the Natural His−
tory Museum, London, UK; CCG, Chengdu College of Ge−
ology, Chengdu, China; CM, Carnegie Museum of Natural
History, Pittsburgh, USA; DMNH, Denver Museum of Natu−
ral History, Denver, USA; DNM, Dinosaur National Monu−
ment, Dinosaur, USA; FMNH, Field Museum of Natural
History, Chicago, USA; FWMSH, Fort Worth Museum of
Science and History, Fort Worth, USA; HMN, Humboldt
Museum für Naturkunde, Berlin, Germany; OMNH, Okla−
homa Museum of Natural History, Norman, USA; ZDM,
Zigong Dinosaur Museum, Zigong, China.
Anatomical nomenclature.—We follow Upchurch et al.
(2004a) in describing scapulae as though oriented horizon−
tally: the coracoid articular surface is designated anterior
and the end commonly called “distal” is designated poste−
rior. See Taylor (2009: 787) for a summary of other schemes
that have been used. Names of clades are used as summa−
rized in Table 1.
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Published Papers
- Taylor, Michael P., Mathew J. Wedel and Richard L. Cifelli. 2011. A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA. Acta Palaeontologica Polonica 56(1):75-98. doi: 10.4202/app.2010.0073
[PDF] [PDF at Acta Pal Pol]
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http://es.wikipedia.org/wiki/Archivo:Brontomerus.jpg
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