(A to I) YPM 204 (part). (A) Dorsal view. (B) Posterior view of the truncated filaments in stacked (A). (C) Same area of (B) with nonstack function. (D and E) The sixth and seventh filaments showing dumbbell-shaped outline, tilted about 40° to the dorsal view. (D) High-contrast backscattered electron (BSE) image. (E) High-contrast, gaseous secondary electron (GSE) image. (F and G) The eighth filament showing dumbbell-shaped outline, tilted about 40° to the dorsal view. (F) BSE image. (G) GSE image. (H and I) Top view of the eighth and ninth filaments showing dumbbell-shaped outlines. (H) BSE image. (I) GSE image. Yellow dotted lines mark the cross section of the filaments (E and G). Arabic numbers are references for locating the cross section of filaments in (A). Asterisks locate the top and bottom inflated marginal bulbs of dumbbell-shaped filaments. Small white arrows indicate the narrow central region of dumbbell-shaped filament. The BSE image distinguishes bright filament from dark surrounding matrix. The GSE image distinguishes dark filament from bright surrounding matrix. ar, article of shaft; lob, lower branch of the limb; upb, upper branch of the limb. Scale bars, 500 μm (A), 100 μm (B and C), and 50 μm (D to I).
Science Daily has a story about trilobite gills. A paper in Science Advances looked at the limbs of trilobites and found that the biramous legs of the trilobites Triarthrus eatoni and Olenoides serratus functioned as gills in a manner similar to the gills of horseshoe crabs.
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.
Trilobites were a group of marine animals with half-moon-like heads that resembled horseshoe crabs, and they were wildly successful in terms of evolution. Though they are now extinct, they survived for more than 250 million years -- longer than the dinosaurs.
Thanks to new technologies and an extremely rare set of fossils, scientists from UC Riverside can now show that trilobites breathed oxygen and explain how they did so. Published in the journal Science Advances, these findings help piece together the puzzle of early animal evolution.
"Up until now, scientists have compared the upper branch of the trilobite leg to the non-respiratory upper branch in crustaceans, but our paper shows, for the first time, that the upper branch functioned as a gill," said Jin-Bo Hou, a UCR paleontology doctoral student who led the research.
