Scientists have revealed the most anatomically complete specimens of Cambrian trilobites ever found in stunning 3D images.
The pristine fossils, which date back to the Cambrian period (541 million to 485 million years ago), were found in 2015 buried under layers of volcanic ash from the Cambrian Tatelt Formation in Morocco. This volcanic burial also preserved the soft tissues of the animals, revealing anatomical features never seen before.
“These new specimens not only preserve antennae and legs, but also mouth structures and even the entire digestive system in three dimensions (3D).” John Pattersonpaleontologist from the University of New England and corresponding author of the study, told Live Science in an email.
Researchers discovered two species of trilobites at the site – Protolenus (Hupeolenus) sp. and Gigoutella mauretanica, dating back 509 million years.
To examine the long-extinct arthropods, scientists used X-ray microtomography – an imaging technique used to see the interior of an object piece by piece – to piece together a virtual 3D model.
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These models captured “the finest details including the animals’ outer surface, every segment of their body, their legs and even the hair structures along their appendages.” Abderrazzak El Albania sedimentologist at the University of Poitiers, lead author of the study, told Live Science in an email.
The stunning preservation and high-quality 3D imaging enabled scientists to observe never-before-seen parts of the trilobite, such as the mouth structures of Protolenus (Hupeolenus) sp., including “a fleshy lobe covering the mouth, of called the labrum, which was documented for the first time in trilobites,” said Albani.
The trilobites were preserved in such good condition for half a billion years thanks to volcanic ash from an ancient eruption that buried the creatures in a manner similar to how Pompeii was preserved after the eruption of Mount Vesuvius in AD 79.
“Because the volcanic ash is so fine, not unlike talcum powder, it can form the smallest anatomical features on the outer surface of these animals, right down to the hairs on their feet,” Paterson said.
“This, along with rapid burial, allowed amazing 3D detail to be preserved in these trilobites,” added Paterson.
Volcanic ash also helped preserve the animals’ insides. In the case of the specimen with its entire digestive system intact, the unfortunate trilobite likely ingested ash in the water before it died, which halted soft tissue degradation, according to the study, published Thursday (June 27) in Science magazine.
Trilobite fossils are found all over the world and are easily recognized by their segmented bodies made of hard exoskeleton. This hard exterior is often well preserved in fossils, which has enabled scientists to identify 22,000 trilobite species that include 298 million years during the Paleozoic eraaccording to the study.