Two dinosaur fossils found in China might fill a 70-million-year evolutionary gap. The relatively recently unearthed dinosaur species, Bannykus and Xiyunykus, belonged to the alvarezsaurid group of dinosaurs and the scientists believe them to be the “missing link” between considerably different ancient reptiles from the late Jurassic and the upper Cretaceous periods.
Alvarezsaurid group of dinosaurs were insectivores with short arms and only one enlarged finger. They were believed to descent from the theropods lineage, a group of carnivore dinosaurs with three-fingered claws. The scientists knew already that these dinosaurs evolved from predators into insectivores in just several million years, but the researchers around the world had no clue on how this transformation took place.
“When we see a transition like that in the fossil record, we always want to know how it happened,” explained Corwin Sullivan, a paleontology professor from the University of Alberta. Sullivan also spent his last ten years collaborating with the Institute for Vertebrate Paleontology in Beijing to find the 70-million-year evolutionary gap.
The finding of Bannykus and Xiyunykus dinosaurs might be the “missing link” the scientists searched for years
Bannykus and Xiyunykus live on Earth about 120 million years ago, in the early Cretaceous period, and they are important assets in the dinosaur fossils record. “These animals are, in a sense, missing links,” Sullivan thinks.
“The teeth are quite a bit smaller, and in particular in the alvarezsaurids of the late Cretaceous, which are usually interpreted as specialized for insect-eating, the teeth get very small, they lose their serrations on a very fine scale,” the researcher added. On the other hand, the one-fingered claws of Bannykus and Xiyunykus dinosaurs means they adapted to digging for food, most probably insects.
“It’s probably a question of exploiting a food resource that was available. They would have been competing with other theropods and other kinds of predators,” explained Sullivan, referring to why these dinosaurs transformed from predators into insectivores.
According to the scientists, the newly discovered dinosaur fossils might indeed be the 70-million-year “missing link” between significantly different dinosaurs from the late Jurassic and the early Cretaceous periods.
Jasmine holds a Master’s in Journalism from Ryerson University in Toronto and writes professionally in a broad variety of genres. She has worked as a senior manager in public relations and communications for major telecommunication companies, and is the former Deputy Director for Media Relations with the Modern Coalition. Jasmine writes primarily in our LGBTTQQIAAP and Science section.