When it come to dinosaurs, names say a lot: “tyrant lizard king” sums up the towering stature and carnivorous ways of Tyrannosaurus rex, and “arm lizard” gestures toward the Brachiosaurus‘s long front legs. And the same is true for the newest discovered dinosaur species, which has been dubbed “thunder-thighs.” That’s because scientists think its muscular thighs were so strong that it used them to boot its enemies.
The official name of this new sauropod species is Brontomerus mcintoshi. The first name is Greek for “thunder-thighs,” and the species name honors the Wesleyan University physics professor and amateur paleontologist Jack McIntosh. This dino is believed to have bigger leg muscles than any other sauropod.
A team of American and British scientists discovered the dinosaur in a quarry in Utah, and published their findings in the journal Acta Palaeontologica Polonica. Fragments from two skeletons were found: one from an adult (believed to be the mother) and a juvenile. These specimens are roughly 110 million year old, and the larger one would have weighed in at six tons and measured over 45 feet long.
While the researchers are delighted to have unearthed a never-before documented dinosaur species, they say the find could have been even better: The fossils are fragmentary because the site had previously been looted. As study coauthor Mike Taylor explains:
“The fossil-hunters basically pillaged this site…. They left behind broken remnants and smashed bits of bone; and in some cases they were using broken bones to hold down tarpaulins — that’s really the most disgraceful aspect of it.” [BBC News]
But they were able to salvage some remains, including a hip bone whose unusual size yielded interesting interpretations. Says Taylor:
“As you put the skeleton together, you can run muscles down from the hip-bone to join at the knee and that gives you a whopping thigh…. What’s interesting is that if it were a sauropod that could move particularly fast, you would expect to see very strong muscles on the back of the leg to pull it along. But we don’t; this is the opposite. It seems most likely to us that what this is about is being able to deliver a strong kick.” [BBC News]
The scientists suggest that these powerful legs could have been used when two males battled for the favor of a female, and could also have been used to fend off predators. This appears to be the first dinosaur whose main weapon is a kick.
The fossil find also changes paleontologists’ view of sauropods in the early Cretaceous period.
“Because sauropods were the most abundant dinosaurs found during the Jurassic Period and the rarest during the Early Cretaceous, there’s long been the perception that sauropods were successful in the Jurassic and were replaced by duckbills and horned dinosaurs in the Cretaceous,” said [study coauthor Matt Wedel]…. “In the past 20 years, however, we are finding more sauropods from the Early Cretaceous period, and the picture is changing. It now seems that sauropods may have been every bit as diverse as they were during the Jurassic, but much less abundant and so much less likely to be found.” [BBC News]
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