TOEFL---IBT閱讀材料：Curious carnivorou​​s dinosaur had a humpback

恐龍這種古老的生物有許多不同的種類，有的恐龍長著翅膀，有的擁有​​可以展開的腳爪，而最新發現的一種則長著非常特別的駝背。


Some dinosaurs had feathers; others had extendable claws or elaborate spikes. But a newly described species is the first to have been found with a distinctively humped back.

The six-meter-long theropod (Concavenator corcovatus) hunted in modern-day Spain some 125 million years ago.

Unlike a camel's fatty hump, this carnivorou​​s dinosaur's bump was made of solid bone. And it was hardly a subtle feature—the eleventh and twelfth vertebrae towered five times taller than the top of the rest of the vertebrae's centra (central portions).

The fossilized skeleton was "almost complete and exquisitely preserved," the researchers noted in the description, published online September 8 in Nature (Scientific American is part of Nature Publishing Group). It was so well conserved over the eons, that the team, led by Francisco Ortega, of the Universidad Nacional de Educacíon a Distancia in M​​adrid, think that they also found evidence of follicles on the animal's forearm—an indication that it might have sported at least a few quill feathers or other protruding elements.

The researchers didn't speculate what function the hump might have served. Other dinosaurs had striking spine-based spikes, such as Stegosaurus, that might have been used for display, fat storage or temperature control. "But the abrupt, tall…singular structure of Concavenator has no analogous structures" among other dinosaurs, the researchers noted.