Trilobites: gills on legs (Introduction)

by David Turell , Wednesday, March 31, 2021, 20:35 (1333 days ago) @ David Turell

A new finding:

https://phys.org/news/2021-03-million-year-old-sea-creatures-leg.html

"A new study has found the first evidence of sophisticated breathing organs in 450-million-year-old sea creatures. Contrary to previous thought, trilobites were leg breathers, with structures resembling gills hanging off their thighs.

***

"A CT scanner was able to read the differences in density between the pyrite and the surrounding rock and helped create three-dimensional models of these rarely seen gill structures.

"'It allowed us to see the fossil without having to do a lot of drilling and grinding away at the rock covering the specimen," said paleontologist Melanie Hopkins, a research team member at the American Museum of Natural History.

"'This way we could get a view that would even be hard to see under a microscope—really small trilobite anatomical structures on the order of 10 to 30 microns wide," she said. For comparison, a human hair is roughly 100 microns thick.

***

"The researchers could see how blood would have filtered through chambers in these delicate structures, picking up oxygen along its way as it moved. They appear much the same as gills in modern marine arthropods like crabs and lobsters.

"Comparing the specimens in pyrite to another trilobite species gave the team additional detail about how the filaments were arranged relative to one another, and to the legs.

"Most trilobites scavenged the ocean floor, using spikes on their lower legs to catch and grind prey. Above those parts, on the upper branch of the limbs, were these additional structures that some believed were meant to help with swimming or digging."

Comment: Amazing finding. They required oxy gen and had to breathe somehow.