The Fattest Belemnite Ever Found Rewrites a Jurassic Family Tree

The breakthrough came when fossil collector Cliff Linster found a second specimen near Ten Sleep, Wyoming, and donated it to the Wyoming Dinosaur Center in 2019. With two fossils to compare, scientists finally had enough evidence to name a new species.

Wyoming paleontologist Bill Wahl, who spotted that the specimen "stuck out like a sore thumb" among countless others, assembled an international team from the United States, the United Kingdom, and New Zealand — including belemnite expert Alexey Ippolitov, a PhD student now at Victoria University of Wellington.

The researchers used computed tomography (CT) scanning — a method that images internal structures without damaging specimens — to examine the fossils in detail.

Why does it matter for evolution?

The scans revealed a surprise: the creature belongs to an ancient belemnite family that scientists believed had disappeared millions of years before it lived. That makes Wyoteuthis linsterorum a relict — a late survivor of a lineage thought to be long gone.

Ippolitov said he was "deeply surprised" to encounter such an unusual specimen in a group already studied so extensively. He also offered a possible explanation for the animal's bulk: "A possible explanation is that their relatively large size gave them an advantage when hunting co-occurring smaller belemnites of the genus Pachyteuthis. Modern squid, after all, are hardly picky when it comes to prey: they readily hunt not only other species of cephalopods, but sometimes even their own kind."

The interpretation remains a hypothesis. Only two fossils are known, and the researchers caution that the species' extreme rarity might reflect narrow ecological specialization, as Dr. Dean Lomax of The University of Manchester noted. Much about how it lived stays uncertain.

Who was Cliff Linster?

The species name linsterorum honors Cliff Linster and his family. Linster discovered one of the only two known specimens and made sure it reached scientists. He also had an impressive fossil-hunting record, including a connection to the famous dinosaur Bambiraptor.

Linster passed away in June, before the study was published. He knew researchers were working on his fossil and looked forward to its formal recognition.

For Dr. Lomax, the naming carries personal weight. He first met the Linsters as a teenager. "I met Cliff and Sandy in 2009, when I spent a week digging up a dinosaur bonebed on their property in northern Montana," Lomax said. "I'm honored to help name this fossil after Cliff. It's bittersweet that he didn't get to see it published, but it's wonderful that we can immortalize him and his family name in the history of paleontology."

What does this change for fossil hunters?

Lippincott stressed that the find shows new species still turn up constantly — and that amateur collectors can contribute directly to science. "After spending years fossil hunting in Wyoming and collecting countless fossils of the common Pachyteuthis belemnites here in Wyoming, this one is unlike anything I have ever seen!" she said.

The study's broader lesson: even fossil groups examined for two centuries can hide major surprises, provided unusual specimens are preserved and made available to researchers.

The genus name Wyoteuthis means "a squid from Wyoming."