Anatomy analysis suggests new dinosaur family tree
Proposal would radically alter century-old groupings
NEW WAY TO RELATE The dinosaur evolutionary tree just got a makeover. One outcome of the proposed rearrangement is that meat-eating evolved twice in dinosaurs (in groups represented by Tyrannosaurus rex, bottom middle, and Staurikosaurus, right), as did traits associated with plant-eating (groups represented by Brontosaurus, left, and Triceratops, top middle).
Clockwise from left: Matt Wedel/Wikimedia Commons (CC BY 4.0); Allie_Caulfield/Wikimedia Commons (CC BY-SA 3.0); Kabacchi/Wikimedia Commons (CC By 2.0); David Monniaux/Wikimedia Commons (CC By-SA 2.0 FR)
The standard dinosaur family tree may soon be just a relic.
After examining more than 400 anatomical traits, scientists have proposed a radical reshuffling of the major dinosaur groups. The rewrite, reported in the March 23 Nature, upsets century-old ideas about dinosaur evolution. It lends support to the accepted idea that the earliest dinosaurs were smallish, two-legged creatures. But contrary to current thinking, the new tree suggests that these early dinosaurs had grasping hands and were omnivores, snapping up meat and plant matter alike.
“This is a novel proposal and a really interesting hypothesis,” says Randall Irmis, a paleontologist at the Natural History Museum of Utah and the University of Utah in Salt Lake City. Irmis, who was not involved with the work, says it’s “a possibility” that the new family tree reflects actual dinosaur relationships. But, he says,
