Of all of the unknown creatures unearthed from the Burgess Shale — a cache of exceptional Cambrian fossils deposited within the Canadian Rockies — none has been fairly as transfixing as Opabinia. And for good cause — with 5 compound eyes and a trunk-like nozzle that resulted in a claw, Opabinia appears otherworldly, like one thing imagined in a science fiction novel, moderately than a swimmer in Earth’s oceans some 500 tens of millions years in the past.
In “Fantastic Life,” his best-selling opus on the Burgess Shale, the evolutionary biologist Stephen Jay Gould labeled Opabinia as a “bizarre surprise,” and mentioned it belonged among the many pantheon of evolutionary icons like Archaeopteryx, Tyrannosaurus rex and archaic human ancestors.
Nonetheless, Opabinia has remained shrouded in evolutionary thriller due to a irritating lack of fossils. The majority of Opabinia specimens had been collected greater than a century in the past and the creature has by no means been discovered exterior of the Burgess Shale.
Which was why Stephen Pates, a paleontologist, was so perplexed when he stumbled upon an odd fossil saved on the Pure Historical past Museum at Kansas College in 2017. On the time, Dr. Pates was a graduate pupil finding out the range of radiodonts, Cambrian predators that sported greedy, claw-like appendages. However the ghostly orange imprint earlier than him lacked the trademark appendages.
“After I first checked out it, I wasn’t positive what it was, however I wasn’t offered that it was a radiodont,” mentioned Dr. Pates, who’s at present a researcher on the College of Cambridge.
The fossil had been unearthed in western Utah, and it had zigzagging physique flaps and a tail brimming with sufficient spikes to make a Stegosaurus jealous. The traits had been paying homage to Opabinia, however the creature’s poorly preserved head was little greater than a crimson smear, obscuring the proboscis and beneficiant allotment of eyes.
To find out the identification of the Cambrian creature, Dr. Pates teamed up with a number of researchers at Harvard College, the place he was a postdoctoral researcher, to run the fossil by means of a wide range of phylogenetic assessments. They in contrast 125 of the fossil’s traits with greater than 50 teams of contemporary and extinct arthropods and constructed detailed evolutionary bushes.
In accordance with Joanna Wolfe, a analysis affiliate at Harvard and co-author of the brand new analysis, the evolutionary bushes allowed the group to rule out radiodonts and conclude that the brand new fossil was doubtless intently associated to Opabinia, the Burgess Shale’s lonely surprise.
In a paper revealed Wednesday in Proceedings of the Royal Society B, the group described the fossil as solely the second opabiniid ever found. They named the brand new species Utaurora comosa, after the Roman goddess of the daybreak, Aurora, who turned her lover right into a cicada — one of many innumerable arthropods that got here after Utaurora.
Whereas the animal nonetheless appears to be like extra alien than arthropod, the researchers consider that Utaurora represents an vital predecessor to the evolution of bugs and crustaceans. Opabiniids had been the primary teams to own backward-facing mouths and their furrowed flaps seem to have been a precursor to segmentation, each frequent traits of contemporary arthropods, based on Dr. Pates.
Nonetheless, it wouldn’t resemble any arthropod dwelling at this time. Because it undulated by means of an historic sea with its flaps and spiky tail fan, Utaurora doubtless wielded its proboscis to shovel meals into its mouth. Opabinia appeared related, though there have been key variations between the 2 species. The youthful Utaurora sported extra spikes on its tail and, at simply over 1 inch lengthy, its physique was half the scale of Opabinia’s.
The researchers consider the brand new discovery places Opabinia in context, illustrating that one of many planet’s strangest creatures was not only a one hit surprise. “They had been a part of the larger image of what was happening and never simply this bizarre curiosity,” Dr. Pates mentioned.
Whereas Opabinia is not distinctive, the minuscule sea creature isn’t any much less charming to Dr. Wolfe, who grew up studying “Fantastic Life,” and credit Gould’s enthralling description of Opabinia as a catalyst for her paleontological profession.
“I assume it’s not truly such a bizarre surprise now, however I don’t assume that makes it much less of a surprise,” she says. “It’s simply not so bizarre.”