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Fish Fossil Offers More Information on Evolution of Animal Jaws: Research
After analyzing 423 million year old fish fossils, researchers from Sweden and China have offered interesting information about evolution of animal jaws. The research team analyzed fish fossils found in China's Yunnan province belonging to Qilinyu rostrata fish species. The study results have been published in journal Science.
Qilinyu rostrata was an armored fish thriving in the lower regions of oceans and belonged to prehistoric class known as placoderms. The fish could have played a role in evolution of animal jaws, the research team informed, after checking jaws of the fossils. The jaws look like sheet metal cutters, as per Dr. Per Ahlberg, a paleontologist at Uppsala University in Sweden. The research team suggests that bony fish and placoderms should not be considered as different branches of evolutionary tree.
The research team added that Qilinyu rostrata was about 12 inches long and possessed the telltale bones present in modern vertebrate jaws including in people.
Earlier research has suggested that placoderms had evolved independently and that our jaw bones must have a separate origin. Researchers found Entelognathus primordialis, another placoderm genus in 2013.
It appears they evolved from the bony plates that placoderms used to sheer flesh in lieu of teeth, said study co-author paleontologist Per Ahlberg.
Study co-leader Zhu Min, a paleontologist at Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology said, “Now we know that one branch of placoderms evolved into modern jawed vertebrates. In this sense, placoderms are not extinct.”
"In us, the lower jaw is made entirely from the dentary. Most of the upper jaw is composed from the maxilla, but the bit that carries the incisor teeth is the premaxilla," Ahlberg said.