Fossils of Silurian sea cucumber found in the United Kingdom | Paleontology



An international team of paleontologists has discovered the remains of an extinct sea cucumber in deposits rich in 430 million year old fossils (Silurian period) in Herefordshire, UK.

Reconstruction of Sollasina cthulhu. Image Credit: Elissa Martin, Invertebrate Paleontology Division, Yale Peabody Natural History Museum.

Reconstruction of Sollasina cthulhu. Image Credit: Elissa Martin, Invertebrate Paleontology Division, Yale Peabody Natural History Museum.

The researchers named the new species Sollasina cthulhu because of its resemblance to the monsters of the fictional universe of Cthulhu created by the author H.P. Lovecraft.

Although the animal was only 3 cm wide, its many tentacles (tubular feet) would have seemed quite monstrous to other small living marine creatures at the time. These tentacles are thought to have been used to catch food and crawl on the sea floor.

Thirteen specimens of Sollasina cthulhu were collected in a single locality of Herefordshire Lagerstätte (a term used by a geologist to refer to an extraordinarily well-preserved fossil bed).

An exceptionally well preserved specimen was selected for a detailed physico-optical tomography study.

3D reconstruction has allowed paleontologists to visualize Sollasina cthulhuInternal ring, which they interpreted as part of the vascular system of water – the system of liquid-filled channels used for feeding and moving living sea cucumbers and their relatives.

"Sollasina cthulhu belongs to an extinct group called ophiocistioids, and this new material provides the first information on the internal structures of the group, "said Dr. Imran Rahman, of the Natural History Museum of the University of Tokyo. Oxford.

"This includes an internal ring shape that has never been described in the group. We interpret this as the first evidence of the soft tissues of the vascular system of water in ophiocistioids. "

The new fossil has been incorporated into a computerized analysis of the evolutionary relationships of sea cucumbers and sea urchins.

The results showed that Sollasina cthulhu and his parents are more closely related to sea cucumbers, rather than sea urchins, shedding new light on the evolutionary history of the group.

"We conducted a number of analyzes to determine whether Sollasina cthulhu was more closely related to sea cucumbers or sea urchins, "said Dr. Jeffrey Thompson of University College London.

"To our surprise, the results suggest that it was an old sea cucumber."

"This helps us understand the changes that occurred during the first evolution of the group, which ultimately gave birth to the slug forms we see today."

The team's paper was published in the journal Acts of the Royal Society B: Biological Sciences.

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Imran A. Rahman et al. 2019. New ophiocistioid Silurian Herefordshire Lagerstätte conserving soft tissues and body plan evolution of sea cucumber. Acts of the Royal Society B: Biological Sciences 286 (1900); doi: 10.1098 / rspb.2018.2792


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