An extinct, cone-shaped creature of the deep that lived some 540 million years ago now has a definitive place on the tree of life, 175 years after it was first discovered.
Researchers from the University of Toronto (UT), in a new study in the journal Nature, say they have found a taxonomic home for the hyolith, a cone-shaped marine animal that had stubbornly resisted definitive classification.
Hyoliths were part of the "Cambrian Explosion" of animals that took place more than 500 million years ago. They diversified and spread themselves out to marine ecosystems everywhere, holding on until about 252 million years ago, when they went extinct.
The animals had long, conical shells and a smaller shell that functioned as a kind of cap to cover the long shell's opening.
The creature was commonly considered to be within the same family as squid and snails, until more than 1,500 specimens from the famed Burgess Shale fossil site in British Columbia showed otherwise.
The specimens examined by the UT researchers had something in their favor that allowed the animal to finally be classified, something characteristic of Burgess Shale fossils: well-preserved soft tissue.