Wyoming Fossils Expose a Barrel-Shaped Jurassic belemnite Unlike Any Other
Two exceptionally rare fossils from Wyoming have forced a reassessment of what Jurassic cephalopods could look like. The newly named Wyoteuthis linsterorum lived about 160 million years ago in the Late Jurassic and belonged to the extinct belemnites, a group of marine animals related to modern squid and octopuses. What makes this animal so unusual is not simply its rarity, but its proportions: the internal skeleton was thick, stout, and barrel-shaped rather than the narrow bullet form seen in most other belemnite fossils from the region.
The fossil record for belemnites is usually dominated by a single structure, the rostrum or guard, which is often the only part that survives. In Wyoming’s Sundance Formation, those remains are abundant and familiar to collectors. Most measure roughly 5 to 10 centimeters long and only 1 to 2 centimeters across. Wyoteuthis linsterorum breaks that pattern completely. Its rostrum is about 10 centimeters long, yet reaches approximately 6 centimeters in width, making it the thickest known belemnite of its kind. In a group long considered well studied, this kind of anatomical departure is hard to ignore.
One fossil stood out so sharply from the surrounding material that it was impossible to mistake for the ordinary Wyoming fare.
An Ancient Cephalopod Built Like a Barrel
The animal’s unusual shape matters because body form often tracks ecology. A broader, heavier internal skeleton may reflect a different swimming style, a different mode of buoyancy control, or a hunting strategy distinct from the more familiar streamlined belemnites. Based on the preserved remains, scientists estimate the full living animal, arms included, may have reached about 60 centimeters in length, or roughly two feet. That is not giant by marine predator standards, but it would have been substantial enough to matter in a Jurassic sea crowded with smaller cephalopods and other prey.
The fossils come from the Sundance Formation, which records an ancient inland sea stretching across much of western North America. That setting matters because it was a dynamic marine ecosystem, not a static lagoon of oddities. In that environment, predators and prey were locked in continuous ecological competition, and even a modest shift in size or anatomy could have changed feeding success. The unusually thick rostrum suggests that Wyoteuthis may have occupied a niche different from its slimmer relatives, perhaps as an active predator better suited to handling certain prey items.
One plausible explanation is simple predation pressure. Belemnites were not passive drifters; they were mobile cephalopods, and modern squid offer a useful behavioral analogy. Squid often hunt other cephalopods, and they do not restrict themselves to one species. A larger body could have given this Jurassic form an edge when hunting co-occurring smaller belemnites such as Pachyteuthis. That does not prove direct predation, but it fits the anatomy and the broader biology of cephalopods, where size, speed, and agility are tightly linked to diet.
CT Scans Revealed an Unexpected Evolutionary Link
The most surprising part of the discovery emerged only after the fossils were scanned. Using computed tomography, the research team examined the internal structure without damaging the specimens. Those scans revealed an unexpected connection to an ancient belemnite family that had been thought to vanish millions of years before this animal lived. For a group studied for more than 200 years, that is a striking result. Long-known fossil lineages can still conceal relict survivors, especially when a specimen is unusual enough to have been overlooked or filed away without deeper analysis.
The species had a long path to recognition. The first specimen was found in the late 1990s by Burkhard Pohl, founder of the Wyoming Dinosaur Center, who recognized that it was much larger than the belemnites he had seen before. Even so, it sat unstudied in a museum drawer for years. A second fossil changed that. Cliff Linster later discovered another specimen near Ten Sleep, Wyoming, and donated it to the Wyoming Dinosaur Center in 2019. With two examples in hand, researchers finally had enough material to compare, confirm, and describe a new species.
The genus name Wyoteuthis means “a squid from Wyoming,” while the species name linsterorum honors Linster and his family. The naming also reflects an important reality in paleontology: major discoveries do not always begin in major laboratories. They often start with field collectors, local experts, and museum specimens that have waited years for the right question to be asked.
A Rare Fossil That Broadens the Jurassic Marine Picture
The rarity of Wyoteuthis linsterorum raises the possibility that it was ecologically specialized. Narrow specialization can make a species uncommon in the fossil record, especially if it lived in a restricted habitat or occupied a specific trophic role. Dean Lomax described the find as exceptionally rare and suggested that its scarcity may reflect adaptation to the environment of the time. Jessica Lippincott, who has spent years collecting Wyoming belemnites, said the specimen was unlike anything she had ever seen after handling countless examples of the common local forms.
That rarity is important because it widens the known range of belemnite body plans. Fossil groups often become familiar through their most common shapes, which can create a false sense of uniformity. Here, the opposite happened: an outlier fossil exposed a body form that had been hiding in plain sight. The discovery shows that even a well-sampled formation can still produce surprises when collectors preserve unusual specimens and researchers are willing to revisit old assumptions.
The final resting place of the only two known fossils is fittingly public. Both are on display at the Wyoming Dinosaur Center in Thermopolis, where they now serve as the clearest evidence yet of one of the Jurassic seas’ strangest squid relatives. The scientific paper describing the animal appears in Papers in Palaeontology, where it adds a rare but important chapter to the evolutionary history of belemnites and the marine ecosystems they inhabited.