Our Jaw Evolved From Placodermi: A 423-Million-Year-Old Armored Fish

– Meet placodermi, an extinct armored fish that lived about 360-43 million years ago. Placoderms were among the first jawed fish. Scientists who have studied two fossils of the fish have announced that humans and placodermi are closely related.

The question of where our jaw came from is not as simple question. All jaws are different and tracing our jawbone’s ancestor has been a difficult scientific task. Now, researchers state that placodermihad the same kind of bones found in our own jaws.

A group of researchers from Uppsala University, Sweden and Chinese Academy of Sciences in Beijing, China have drawn the conclusions after studying fossils of two armored fish from the Silurian period.

Placodermi, which means plate-skinned in Greek was a predator that lived in in Silurian waters.

The Silurian Period follows the Ordovician Period in the Paleozoic Era. It began around 443 million years ago and lasted for 26 million years. Like the periods that have come before, it is named for an ancient Celtic tribe that lived in Wales where the geologic evidence was found.

Placoderms were the dominant species in world seas until the end of the Devonian period. As fierce as some Placoderms were, they persisted only 50 million years, which is really a very short period of time in comparison with the 400 million year history of sharks.

Swedish and Chinese scientists studied the Entelognathus fossil, which was found in 2013 in rock formations at the Xiaoxiang reservoir in China’s Yunnan province along with another fossil of an armored fish that lived at the same time.

The results show that the two fish are very dissimilar, but taken together they confirm the view that the jawbone construction has been passed on through evolution.

“The discovery of Entelognathus revealed the presence of maxilla, premaxilla, and dentary…in a Silurian placoderm,” the researchers wrote in their study published in the journal Science.So if you are wondering if it’s really possible our jaws evolved from ancient, armored fish, then according to these scientists the answer is – yes.


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