The paper, "Rapid volcanic ash entombment reveals the 3D anatomy of Cambrian trilobites," was published in the journal, Science.

The trilobites, from the Cambrian period, have been the subject of research by an international team of scientists, led by Prof Abderrazak El Albani, a geologist based at University of Poitiers and originally from Morocco. The team included Dr. Greg Edgecombe, a paleontologist at the Natural History Museum.

Dr. Greg Edgecombe said, "I've been studying trilobites for nearly 40 years, but I never felt like I was looking at live animals as much as I have with these ones. I've seen a lot of soft anatomy of trilobites, but it's the 3D preservation here that is truly astounding.

"An unexpected outcome of our work is discovering that volcanic ash in shallow marine settings could be a bonanza for exceptional fossil preservation."

Due to their hard, calcified exoskeleton often being well-preserved in the fossil record, trilobites are some of the best studied fossil marine animals. Over 20,000 species have been described by paleontologists over the past two centuries.

However, until now, comprehensive scientific understanding of this phenomenally diverse group has been limited by the relative scarcity of soft tissue preservation. Owing to the fact the Moroccan trilobites were encased in hot ash in sea water, their bodies fossilized very quickly as the ash transformed to rock—meeting a similar end to the inhabitants of Pompeii following the eruption of Mount Vesuvius.