Wyoteuthis linsterorum: the chunkiest squid relative from Jurassic Wyoming

A fossil that locals call a squid butt has just turned out to be something much stranger. Scientists have named a new extinct relative of squid, Wyoteuthis linsterorum, from two rare fossils found in Wyoming. Its bullet-shaped inner skeleton is about 6 centimeters wide, while most belemnites from the same region measure just 1 to 2 centimeters across. That makes it the thickest known belemnite of its kind.

A sea over Wyoming, 160 million years ago

Around 160 million years ago, during the Jurassic Period, a shallow inland sea covered much of the western United States. Animals called belemnites swam in it by the thousands. They were cephalopods, which puts them in the same big family as modern squid, octopuses and cuttlefish, though they are not squid themselves. Belemnites had arms with tiny hooks, a soft body, and a hard, bullet-shaped skeleton called a rostrum inside the rear of the body.

Soft tissue almost never fossilizes, so the rostrum is usually all that remains. Wyoming has so many of them that local palaeontologists nickname them squid butts. Typical ones run about 5 to 10 centimeters long and 1 to 2 centimeters wide, and collectors find them all the time.

Two fossils that stood out

The first specimen turned up in the late 1990s. Dr. Burkhard Pohl, founder of the Wyoming Dinosaur Center, found it, and it then sat unstudied in a collection drawer for many years. Nobody had a second example to compare it with, so it stayed a curiosity.

That changed when fossil collector Cliff Linster found a second, similar rostrum near Ten Sleep, Wyoming, and donated it to the Wyoming Dinosaur Center in 2019. Wyoming palaeontologist Bill Wahl said it stuck out like a sore thumb compared with the countless other belemnites from the region. Jessica Lippincott, another Wyoming palaeontologist, called it unlike anything she had ever seen.

What makes it so chunky

The team, which includes Dr. Dean Lomax of the University of Manchester and belemnite expert Alexey Ippolitov, studied both fossils. The better specimen has a rostrum about 10 centimeters long and up to 6 centimeters wide. That is several times thicker than a typical Wyoming belemnite of similar length. Ippolitov said he was deeply surprised by it.

Because the rostrum is the only part that survives, the researchers estimated the size of the whole animal by comparing it with other belemnites. They suggest the living animal, arms included, measured about 60 centimeters, or roughly two feet. So the creature was not huge. It was simply built far stouter than its neighbors.

The scientists named the species after Cliff Linster, who died in June 2026. The fossils come from the Sundance Formation, which preserves that Jurassic seaway.

Why it matters

A new species this different, sitting in a region where belemnites are everywhere, shows how much a well-studied fossil bed can still hide. It also shows the value of museum drawers. Without the older specimen on file, the second fossil might have looked like a one-off oddity instead of part of a pattern.

Lomax said the find is incredibly rare, and that might reflect some ecological adaptation to the environment at the time. In other words, a fatter rostrum may have suited a particular way of life in that sea.

What we still do not know

Only two specimens exist, so the picture is thin. Scientists have not shown why the animal grew such a thick rostrum, and the idea of an ecological adaptation is a suggestion, not a conclusion. The two-foot body size is an estimate, not a measurement. More fossils from the same rocks could change the story.

Still, the discovery adds one more strange shape to the story of ancient cephalopods, and it started with a fossil in a drawer.

Sources

• University of Manchester news release, 10 September 2026, based on the study in Papers in Palaeontology, doi 10.1002/spp2.70123: https://www.manchester.ac.uk/about/news/peculiar-new-species-of-jurassic-squid-found-in-wyoming/
• ScienceDaily, 20 October 2026: https://www.sciencedaily.com/releases/2026/10/261019093434.htm