It measured between 10 and 50 millimeters, was shaped like a hockey stick, was thin as a pin, 14 spines protruded from its back, and its slender legs ended in a pair of claws. So was this worm-like creature that lived 508 million years ago and from whose family most of today’s invertebrates come , according to the latest study from the University of Cambridge (United Kingdom) and collected by the journal Nature .
The discovery of Hallucigenia sparsa (which lived during the Cambrian explosion ), as this animal is called, has been possible thanks to the reconstruction of a group of fossils discovered on the side of a mountain in Yoho National Park, in the Rocky Mountains. from Canada in the 70s. Its characteristic appearance has caused confusion in the scientific community all these years, since there were still doubts as to where exactly the head was located or if the spines were tentacles.
“When we put the fossils under the microscope, we already expected to find a pair of eyes, but our surprise came when we also found teeth that were smiling at us. This teeth is a complex morphology for such an ancient species. We were hoping to find a more primitive anatomy , ”explains Martin R. Smith, study leader.
Hallucigenia sparsa is classified within the panarthropod family , from which species such as velvet worms and arthropods derive, where arachnids or crustaceans are also found. “Our findings allow us to know that these species once had complex mouthparts that were simplified: these groups lost their teeth as evolution progressed,” says Smith.
According to the work, all species that change their skin share a common ancestor , “something that until now had only been determined through molecular DNA analysis,” says Smith.
