Brontomerus pode ter sido um grande chutador

quarta-feira, fevereiro 23, 2011

'Thunder-Thighs' Dinosaur Discovered: Brontomerus May Have Used Powerful Thigh Muscles to Kick Predators

ScienceDaily (Feb. 23, 2011) — A new dinosaur named Brontomerus mcintoshi, or "thunder-thighs" after its enormously powerful thigh muscles, has been discovered in Utah, USA. The new species is described in a paper recently published in the journalActa Palaeontologica Polonica by an international team of scientists from the UK and the US.

Reconstruction of Brontomerus mcintoshi in combat with a predator. (Credit: Francisco Gasc)

A member of the long-necked sauropod group of dinosaurs which includes Diplodocus andBrachiosaurus, Brontomerus may have used its powerful thighs as a weapon to kick predators, or to help travel over rough, hilly terrain.Brontomerus lived about 110 million years ago, during the Early Cretaceous Period, and probably had to contend with fierce "raptors" such as Deinonychus and Utahraptor.

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. Paleontologists speculate that the larger specimen is the mother of the younger and would have weighed around 6 tons, about the size of a large elephant, and measured 14 meters in length. 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.

The authors classified the new genus based on an incomplete skeleton including bones from the shoulder, hip, ribs, vertebrae and some unidentifiable fragments. They used the bones to identify Brontomerus' unique features, primarily the shape of the ilium (hip bone), which, in the case of Brontomerus, is unusually large in comparison to that of similar dinosaurs. The wide, blade-shaped bone projects forward ahead of the hip socket, providing a proportionally massive area for the attachment of muscles.

Read more here/Leia mais aqui: Science Daily


A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA

Michael P. Taylor, Mathew J. Wedel, and Richard L. Cifelli

Acta Palaeontologica Polonica 56 (1), 2011: 75-98 doi:10.4202/app.2010.0073

Brontomerus mcintoshi is a new genus and species of sauropod dinosaur from the Hotel Mesa Quarry in Grand County, Utah, USA, in the upper part of the Ruby Ranch Member (Aptian–Albian) of the Lower Cretaceous Cedar Mountain Formation. It is known from at least two fragmentary specimens of different sizes. The type specimen is OMNH 66430, the left ilium of a juvenile individual; tentatively referred specimens include a crushed presacral centrum, a complete and well−preserved mid−to−posterior caudal vertebra, the partial centrum of a distal caudal vertebra, a complete pneumatic anterior dorsal rib from the right side, the nearly complete left scapula of a much larger, presumably adult, individual, and two partial sternal plates. 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 30o 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.

Michael P. Taylor [], Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom; Mathew J. Wedel [], College of Osteopathic Medicine of the Pacific and College of Podiatric Medicine, Western University of Health Sciences, 309 E. Second Street, Pomona, California 91766−1854, USA; Richard L. Cifelli, [], Sam Noble Oklahoma Museum of Natural History, 2401 Chautauqua, Norman, Oklahoma 73072, USA.