Trilobites were a group of marine animals with crescent-shaped heads that resembled horseshoe crabs. And according to a new study, they breathed through their legs, with gill-like structures hanging from their thighs .
This means that we are looking at the first evidence of sophisticated respiratory organs in 450 million year old marine creatures.
High precision first scan
The research was made possible, in part, because of unusually preserved fossil specimens. More than 22,000 species of trilobites have been discovered, but the soft parts of the animals are visible in only about two dozen. According to the UCR professor of geology and co-author of the article, Nigel Hughes :
These were preserved in pyrite, fool’s gold, but it is more important than gold to us, because it is key to understanding these ancient structures.
A CT scanner was able to read the density differences between the pyrite and the surrounding rock and helped create three-dimensional models of these rarely seen gill structures. This allowed the fossil to be seen without much drilling and polishing of the rock covering the specimen .
According to paleontologist Melanie Hopkins , a member of the research team at the American Museum of Natural History:
This way we could get a view that would even be difficult to see with a microscope: really tiny trilobite anatomical structures on the order of 10 to 30 microns across.