Dinosaur tooth reveal some have been choosy eaters

Some dinosaurs have been fussy eaters.

Certain herbivorous dinosaurs preferred specific parts of plants, difficult long-standing assumptions about their diets, a examine of fossilized dino tooth reveals. The evaluation of calcium isotopes in 150-million-year-old tooth enamel reveals that weight-reduction plan might have depended much less on the scale of dinosaurs and extra in regards to the dietary worth and texture of their meals, researchers report within the Oct. 1 Palaeogeography, Palaeoclimatology, Palaeoecology.

“My big takeaway is that the herbivores had different diets, and it is likely that the parts of a plant that these animals eat [are] a more significant driver than height,” says Liam Norris, a paleontologist on the Texas Science & Natural History Museum in Austin. “So, if they are eating softer parts like leaves versus eating twigs or maybe bark, that looks like it is more significant.”

Norris and colleagues in contrast calcium isotope ranges in dinosaur enamel with the degrees in enamel from fashionable herbivores. The crew discovered that the towering sauropod Camarasaurus ­— from the Late Jurassic interval, between about 164 million and 145 million years in the past, lengthy thought to feed primarily from treetops — ate extra woody vegetation and twigs than anticipated. But the smaller, beaked Camptosaurus most well-liked softer plant components equivalent to leaves and buds.

This discovering goes towards widespread knowledge that giant dinosaurs had the decide of what they ate.

“People have been looking at dinosaur teeth for many decades, and this is a nice new method for looking at the same kind of problem,” says dinosaur professional Paul Barrett of the Natural History Museum in London, who was not concerned within the examine. “This would be most useful in those cases where dinosaur diets are a bit ambiguous and we don’t know too much about what’s going on.”

Norris’ crew additionally measured calcium isotope ranges within the tooth of two meat-eaters and in contrast them with fashionable carnivorous animals. The crew’s outcomes recommend that the crocodile-like Eutretauranosuchus ate principally fish, and the fierce theropod Allosaurus dined totally on the flesh of different dinosaurs — however not as a lot on their bones, as did the later theropod Tyrannosaurus rex, which lived throughout the Late Cretaceous between 68 million and 66 million years in the past.

The researchers gathered a few of their samples from the Carnegie Quarry, a well-known fossil web site in Utah’s Dinosaur National Monument. The web site lies throughout the huge Morrison Formation, first found within the 1870s, which has yielded a trove of Late Jurassic fossilized dinosaur bones. Some of the tooth had already been eliminated and categorised by earlier researchers, however others Norris and colleagues sampled straight from the quarry wall itself.

While some earlier research examined calcium isotopes in fossilized teeth from the broader Morrison Formation, Norris says, the brand new examine is the primary to look at dinosaur tooth unearthed solely on the Carnegie Quarry web site — believed to have as soon as been a riverbed or oxbow lake the place dinosaur bones piled up.

The methodology of figuring out diets from calcium isotopes in tooth enamel is effectively established, however that is one in every of its first makes use of on dinosaur tooth which are so outdated, says paleontologist Michael Benton, who was not concerned within the examine. “I think this is an innovative method, and technically quite difficult,” says Benton, of the University of Bristol in England.

Barrett notes that the examine establishes the measurement of calcium isotopes in dinosaur tooth enamel as a legitimate scientific inquiry. “This is nice confirmation that these kinds of chemical signatures are preserved in the teeth for so long.”