Final Turn of Ezekiels Wheel’ Tribute to Yale Fossil Hunter

The mystery of Ezekiel’s Wheel—the extinct sea creature, not the Biblical vision—may have taken its final twist, thanks to Yale paleontologists.

With this, the researchers have finally given a scientific name to the favorite fossil of a beloved amateur fossil hunter.

Samuel J. Ciurca Jr., who died in 2021, was a longtime curator at the Yale Peabody Museum. He collected tens of thousands of fossils, mainly from the Silurian rocks of New York State and southern Ontario, Canada.

He donated more than 11,000 fossil sea scorpions, called sea scorpions, to the Peabody Museum – the Ciurca Collection in the Peabody’s Division of Invertebrate Paleontology.

One of these, which may be the largest complete sea scorpion ever discovered, is a 4-foot specimen of the giant pterygotid Acutiramus macrophthalmus, which will be on display when the Peabody reopens to the public in 2024 after a major number of operations. years of renovation.

But while the vast majority of Ciurca’s fossils are eurypterids – extinct sea scorpions found around most of the world in rocks ranging in age from 465 to 250 million years – his favorite fossil was something else entirely. Something unidentified.

He called it the wheel of Ezekiel, after the Old Testament reference to the prophetic vision of a warrior in a wheeled chariot. Ciurca discovered ten specimens of the unknown animal in Ontario starting in the mid-1990s.

“He wrote the back of the best specimen, the first specimen he discovered, with the words ‘the most beautiful fossil ever found,’” says Derek Briggs, the G. Evelyn Hutchinson Professor of Earth and Planetary Sciences in the Yale Faculty of Arts . and Sciences, and a long-time Ciurca employee.

The small ones consist of a circular assembly of radiation tubes arranged in two or more levels – hence the nickname “wheel”. The length of the tubes is no less than three-quarters of an inch.

“Ezekiel’s wheel has been a mystery for a long time,” Briggs said. “Several years ago, a then graduate student of mine, Nicolás Mongiardino Koch, tried to find out what it was as a class project for my course ‘Extraordinary Glimpses of Past Life.'”

“He has made significant progress on a solution, but additional specimens that came to light as we acquired more of Sam’s collection after his death added important new information.

“With a new study,” Briggs added, “we now have an answer to the mystery.”

In a new study published in the journal Current Biology, Briggs and Mongiardino Koch, now at the University of California San Diego, identify Ezekiel’s Wheel as a 420-million-year-old representative of a group still found in modern oceans. , known as hemichordates.

Although hemichordates are now rare, their ancestors were quite abundant. The most common were known as graptolites, and were often found in Paleozoic plankton; graptolite fossils play an important role in correlating sedimentary sequences in research.

Less common ancient hemichordates were creatures called cephalodiscids that are still alive today. Both their living and extinct forms lived exclusively on the seabed – or so it was thought.

“It turns out that Sam’s fossil is a very unusual cephalodiscid that evolved a conical structure that we interpret as a float — it is the only cephalodiscid known to have colonized the plankton,” Briggs said.

The researchers named it Rotaciurca superbus: ‘rota’, which is Latin for ‘wheel’, ‘ciurca’ after the fossil hunter who found it beautiful, and ‘superbus’, the Latin word for ‘beautiful’.

They assigned Rotaciurca superbus to a new family, Ezekielidae, emphasizing its status as an extinct fossil cephalodiscid outside the living group.