American and Indian scientists have discovered that millions of years ago, the most common animal in the oceans, “trilobites”, absorbed oxygen from their legs, that is, they breathed.
These animals, which appeared about 570 million years ago, ruled the oceans for a long time and became extinct about 270 million years ago.
Trilobites were so numerous not only in their species but also in their numbers that even today the fossil record contains the most of their remains, most of which are in extremely safe and complete condition.
Although trilobites belonged to the phylum Arthropoda, to which all modern-day insects belong, they are still not considered “insects.”
Along with dozens of legs, stiff shells and dismembered bodies, they could range in length from one millimeter to 700 millimeters. However, the average length of trilobites has been found to be 50 to 60 mm.
In a study published online in the latest issue of the online research journal Science Advances, scientists from the University of California (Riverside), the American Museum of Natural History (New York) and the Indian Statistical Institute (Kolkata) said: Using computerized tomography (CT) method, trilobite fossils were observed more closely than ever before.
The CT scanner obtained three-dimensional (3D) and highly detailed (high-resolution) images of trilobite fossils, which could show physical features as thin as 10 microns to 30 microns.
For comparison, the average thickness of a normal human hair is 70 microns. That is, the details seen with the help of CT scan were seven times thinner than human hair!
While examining the same images (CT scans) of Trilobites, the scientists found microscopic dumbbell-like fibers in the upper parts of their legs that resembled the gills of existing fish.
After further investigation and analysis, experts have finally come to the conclusion that trilobites absorb the oxygen in the water (ie, breathe) with the help of the same fibers on their legs.
This discovery is not only interesting in itself but also important in that it will help us to understand the evolution of the respiratory system in aquatic animals, especially the gallbladder.
In addition, meticulous 3D computerized scanning can help us in many future investigations.