Having lost almost the entire back of the body and eyes in a fight with a large predator, the trilobite managed to survive and even partially recover.
The long era of dinosaurs was preceded by the Paleozoic era. Then one of the dominant marine animals were trilobites - representatives of a separate class of arthropods that appeared more than 500 million years ago and after 250 million years were completely extinct. In this interval, trilobites flourished, and today thousands of species of these animals are known, numerous remains of which are found everywhere.
The same find was made by Czech paleontologists. It has been dated to 450 million years old and referred to as Dalmanitina socialis. The sample turned out to be extremely unusual: before the final death, this trilobite suffered severe injuries. The fossil retained only a powerful head with deep scars on its carapace and one twisted eye. Scientists write about this in an article accepted for publication in the International Journal of Paleopathology.
According to them, such injuries are usually fatal, but this trilobite somehow survived and even partially regenerated the lost eye, although it was distorted. “Shifted backward, incorrectly oriented, with a rather irregular lens organization, it was nevertheless a fully functional organ,” write the authors of the work. Note that the eyes of trilobites are perhaps the most ancient in nature, so they attract the attention of specialists.
Finds like this one are very rare: apparently, trilobites with severe eye damage were quickly eaten without a trace. One can only recall a fossil found in Norway with an eye pierced, apparently, by a sharp shell of a mollusk. The survival of the trilobite and the partial recovery of the severely damaged eye were a completely unique case.
Scientists believe that the wounds on the sample from the Czech Republic were left by one of the ancient and implacable opponents of trilobites - crustaceans (eurypterids). These animals existed in the sea at the same time as trilobites. They were relatives of modern fur-tails (and more distant relatives of arachnids), although outwardly they really looked like large, and sometimes just huge - a meter or more - half-scorpions, half-rats. Trilobites served them as food, and Czech paleontologists are sure that it was the claws of the crustacean that left deep scars on the remains.