Some dinosaurs have been fussy eaters.
Sure herbivorous dinosaurs most well-liked particular elements of crops, difficult long-standing assumptions about their diets, a research of fossilized dino tooth exhibits. The evaluation of calcium isotopes in 150-million-year-old tooth enamel reveals that weight-reduction plan could have depended much less on the dimensions 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 huge takeaway is that the herbivores had totally different diets, and it’s possible that the elements of a plant that these animals eat [are] a extra vital driver than peak,” says Liam Norris, a paleontologist on the Texas Science & Pure Historical past Museum in Austin. “So, if they’re consuming softer elements like leaves versus consuming twigs or possibly bark, that appears like it’s extra vital.”
Norris and colleagues in contrast calcium isotope ranges in dinosaur enamel with the degrees in enamel from fashionable herbivores. The workforce 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 crops and twigs than anticipated. However the smaller, beaked Camptosaurus most well-liked softer plant elements akin to leaves and buds.
This discovering goes in opposition to frequent knowledge that giant dinosaurs had the decide of what they ate.
“Individuals have been dinosaur tooth for a lot of a long time, and it is a good new technique for wanting on the identical type of drawback,” says dinosaur skilled Paul Barrett of the Pure Historical past Museum in London, who was not concerned within the research. “This is able to be most helpful in these instances the place dinosaur diets are a bit ambiguous and we don’t know an excessive amount of about what’s happening.”
Norris’ workforce additionally measured calcium isotope ranges within the tooth of two meat-eaters and in contrast them with fashionable carnivorous animals. The workforce’s outcomes counsel that the crocodile-like Eutretauranosuchus ate largely 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 through 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 website in Utah’s Dinosaur Nationwide Monument. The positioning lies inside the huge Morrison Formation, first found within the 1870s, which has yielded a trove of Late Jurassic fossilized dinosaur bones. Among the tooth had already been eliminated and labeled by earlier researchers, however others Norris and colleagues sampled instantly from the quarry wall itself.
Whereas some earlier research examined calcium isotopes in fossilized tooth from the broader Morrison Formation, Norris says, the brand new research is the primary to look at dinosaur tooth unearthed solely on the Carnegie Quarry website — believed to have as soon as been a riverbed or oxbow lake the place dinosaur bones piled up.
The tactic of figuring out diets from calcium isotopes in tooth enamel is nicely established, however that is one in every of its first makes use of on dinosaur tooth which might be so outdated, says paleontologist Michael Benton, who was not concerned within the research. “I believe that is an modern technique, and technically fairly troublesome,” says Benton, of the College of Bristol in England.
Barrett notes that the research establishes the measurement of calcium isotopes in dinosaur tooth enamel as a legitimate scientific inquiry. “That is good affirmation that these sorts of chemical signatures are preserved within the tooth for thus lengthy.”
