Scientists Have Finally Classified Mysterious Cone-Shaped Sea Creatures

Posted: Jan 12 2017, 12:32pm CST | by , Updated: Jan 12 2017, 12:41pm CST, in News | Latest Science News

 

Scientists have Finally Classified the Mysterious Cone-Shaped Creatures
The artist's impression of hyolith. Credit: Credit: Artist: Danielle Dufault. © Royal Ontario Museum
 

The extinct hylothis are closely related to brachiopods, a group of marine animals with shells

About 175 years ago, small sea creatures with cone-shaped shells and long arms and tentacles were discovered by the paleontologists. The creatures, known as hyoliths, were so unusual that it was difficult to tell where they fit on the evolutionary tree.

The interesting thing is that these marine creatures have finally found their true identity. The now-extinct hyoliths existed about 530 million years ago during the Cambrian period and were among the first animals known to have evolved external skeletons.

For years, hyoliths were thought to belong to the same family as snails, squid and other mollusks. But new research suggests that they were indeed more closely related to brachiopods, a group of marine animals that have hard shells in the upper and lower parts. Brachiopods used to open their fronts for feeding and then close it for the protection of their inner parts of the body.

Though hyoliths were abundant and widely distributed across the world but their fossil record could not yield sufficient information about the creature, mainly because of the absence of soft tissue of the critter. Therefore, the taxology and ecology of this species was largely remained unsolved. 

In 2014, a team of Canadian scientists led by 20-year-old University of Toronto undergraduate student Joseph Moysiuk, have found a hyolith fossil in the renowned fossil-rich site Burgess Shale of British Columbia with extremely well-preserved soft tissues including the tentacle-bearing organ surrounding a central mouth.

The fossils of this particular kind of hyolith, the Haplophrentis enabled researchers to reconstruct the physical features of the animal and helped them establish its classification. Researchers found that hyoliths mouth's structure is very similar to brachiopods even though they belong to totally different branches.

“Our most important and surprising discovery is the hyolith feeding structure, which is a row of flexible tentacles extending away from the mouth, contained within the cavity between the lower conical shell and upper cap-like shell,” said Moysiuk. 

“Only one group of living animals - the brachiopods - has a comparable feeding structure enclosed by a pair of valves. This finding demonstrates that brachiopods, and not molluscs, are the closest surviving relatives of hyoliths.

Most of the hylothis remains have distinctive yet similar physical structures which prevented researchers to classify them before. However, the newly discovered fossil from Cambrian Burgess Shale in British Columbia provided a fresh perspective on the evolutionary history of hylothis.

“Burgess Shale fossils are exceptional because they show preservation of soft tissues which are not usually preserved in normal conditions,” said co-author Jean-Bernard Caron. “Our most recent field discoveries were key in finally cracking their story, around 175 years after the first description of a hyolith.”

The findings are important not only for studying the origin and early evolution of this specific animal living in the Cambrian period but it also adds to researchers understanding of the Cambrian Explosion, a short evolutionary period started around 542 million years ago when most major animal groups emerge in the fossil record.

Co-author Martin Smith at Durham University in the United Kingdom says. “Our study reiterates the importance of soft tissue preservation from Burgess Shale-type deposits in illuminating the evolutionary history of creatures about which we still know very little."

 

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Hira Bashir covers daily affairs around the world.

 

 

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