Oxygen and the Cambrian: gills appear (Evolution)

by David Turell , Wednesday, February 09, 2022, 14:15 (806 days ago) @ David Turell

A new Chinese find, early gills from 520 million years ago:

http://www.sci-news.com/paleontology/erratus-sperare-10530.html?utm_source=feedburner&a...

"Erratus sperare lived in what is now China during the Early Cambrian epoch, some 520 million years ago.

"Its fossilized remains were discovered at the Chengjiang Fossil Site, a UNESCO World Heritage Site located in the Chinese province of Yunnan.

***

"Modern water dwelling arthropods have biramous limbs, legs that have two parts — one for breathing and one for walking — but how such specialized limbs evolved was a mystery.

"Some of the earliest fossil arthropods, like Anomalocaris, had swimming flaps that may have doubled as gills.

"But, until now, paleontologists didn’t know how arthropods made the jump from these specialized flaps to the biramous limbs of modern arthropods.

"Erratus sperare provides the missing link between stem-Euarthropoda and Deuteropoda — arthropods that used such specialised flaps and those with biramous limbs.

"According to Dr. Legg and his co-authors, the ancient arthropod had both limbs and flaps.

“'Fish aren’t the only organisms that have gills! Arthropods have gills too… they just have them on their legs,” Dr. Legg said.

“'When it came to arthropods, however, we just weren’t sure where these gills came from.”

“Thanks to this new fossil, Erratus sperare, we now have a much clearer idea,” he added.

“'These gills also probably went on to evolve into the wings of insects and the lungs of terrestrial arthropods like spiders so were a very important innovation.'”

Comment: These animals had to utilize oxygen somehow. This is probably the beginning.