Chaetae are stiff bristles made of chitin that characterize many species of annelid worms.
Shaihuludia shurikeni inhabited the Cambrian seas approximately 507 million years ago.
The ancient creature was a type of annelid, a diverse group of segmented worms found in terrestrial, freshwater and marine environments all over the world.
Shaihuludia shurikeni was 7 to 8 cm (2.8-3.1 inches) long, had a wide body and flattened fans of fused blade-like chaetae.
“Annelids are an extremely diverse phylum (around 21,000 described species) and have conquered a variety of terrestrial, freshwater, and marine environments,” said Dr. Julian Kimmig, a paleontologist at the Staatliches Museum für Naturkunde Karlsruhe and the University of North Dakota.
“However, their whole-body fossil record is sparse. Their soft-bodied nature typically results in rapid decay, restricting most of their fossil occurrences to Lagerstätten-type deposits.”
“The oldest accepted whole-body annelids appear in the early Cambrian of China and Greenland and are present from this point forward in the Lagerstätten of the Cambrian.”
“They reach a peak known-diversity within the period by the middle Cambrian, with six species from the Burgess Shale alone.”
“Most annelid taxa known from the Cambrian belong to the annelid stem group,” they added.
“These organisms typically show homonymous segmentation with a single pair of head appendages and in some cases with a median antenna.”
The single specimen of Shaihuludia shurikeni was collected from the Spence Shale Member of the Langston Formation in northern Utah and southern Idaho, the United States.
“The Cambrian Spence Shale Lagerstätte of northeastern Utah and southeastern Idaho preserves one of the most diverse Burgess Shale-type biotas in Laurentia,” the paleontologists said.
“Its fauna comprises over 90 species, of which about one-third are soft-bodied.”
“The soft-bodied remains are dominated by arthropods, but also…
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