For those who traveled throughout what’s now North America round 75 million years in the past, you’d see vastly totally different dinosaur species in all places you went. The dramatic variation on this interval’s fossils, discovered all through the western half of the continent, has lengthy puzzled paleontologists. Some have proposed that mountains or rivers may need remoted evolving dinosaur populations, resulting in larger range. However a brand new research suggests a special chance. A part of the reply, researchers report within the journal Palaeontology, rests in what herbivorous dinosaurs have been munching on.
Paleontologists can examine dinosaur diets by taking a look at geochemical isotopes—variations of parts with totally different numbers of neutrons—present in fossilized bones. As herbivorous dinosaurs digested ferns and conifers, for instance, isotopes of oxygen, carbon and strontium from these vegetation collected in numerous proportions. Researchers have recognized the distinct ratios related to every plant kind and the areas the place it grew; measuring the isotopes in dinosaur bones can inform consultants not solely what these animals ate however the place they ventured for meals.
Within the new research, Carleton College paleontologist Thomas Cullen and his colleagues appeared on the horned ceratopsids, armored ankylosaurs and duck-billed hadrosaurs of southern Alberta’s Oldman Formation. Horned and armored dinosaurs walked on all fours with their heads close to the bottom, and isotope ratios present these dinosaurs ate low-growing vegetation in a comparatively restricted geographic space. However the duck-billed dinosaurs, Cullen and co-authors discovered, may attain larger foliage within the bushes and ate up a broader vary of vegetation—and these animals ranged so far as 100 kilometers in the hunt for sustenance. “I used to be initially shocked at simply how totally different the hadrosaurs are from the ankylosaurs and ceratopsids” of their consuming and journey habits, Cullen says.
If horned and armored dinosaurs foraged solely in comparatively constrained areas, such dietary restrictions may need helped drive the evolution of their many new species in every habitat—whereas duck-billed species, whose people had broader geographic ranges, present far much less variation. “This research is an instance of how using geochemical and high-precision analytical methods continues to permit paleontologists to make vital interpretations of ecology and biology of historical ecosystems,” says College of Arkansas geologist Celina Suarez, who was not concerned within the analysis.
Such work may supply new insights into dinosaur species’ distribution 75 million years in the past, says Andrew Farke, a curator on the Raymond M. Alf Museum of Paleontology in Claremont, Calif., who additionally was not concerned. “I’d wager the weight loss plan of hadrosaurs in all probability pertains to the broad distribution of their species,” he provides.