Paleontologists have identified an entirely new squid-like creature from the Jurassic from a pair of fossils recovered from the floor of an ancient inland sea in Wyoming. They say it is one of the “thickest known species” of its prehistoric group. Wyoteuthis linsterorum is the name of the species, in recognition of the experienced fossil collector Cliff Linster, who discovered one of the fossils, but died earlier this year. It is the only species of Wyoteuthis so far. The species made its scientific debut in the journal Papers in Palaeontology. A map showing where the fossils were found, in the Redwater Shale layer of the Sundance Formation. (Ippolitov et al., Papers in Palaeontology, 2026) Wyoteuthis is a member of an extinct order of cephalopods, the belemnites, which proliferated during the Jurassic. Its living relatives include octopuses and squid. Like modern squids, belemnites had 10 appendages, but they also had a cone-shaped inner shell. Part of the shell was made of aragonite, like that of modern cephalopods. You may have seen the floating, foam-like bone of a cuttlefish washed up on the beach: that’s aragonite. But the other part of a belemnite’s internal structure, known as the guard or rostrum, is made of calcite. They are those calcitic structures found scattered throughout the Sundance Formation and other fossil deposits around the world, evidence that belemnites were once abundant in Jurassic seas. Wyoteuthis fossils are around 160 million years old. But Wyoteuthis is unlike any other belemnite experts have ever seen, with a rostrum so round that even scientists have literally described it as “one of the thickest species known in the group’s paleontological history.” Wyoming paleontologist Bill Wahl, who has been searching for fossils in Wyoming for much of his career, says the species “sticks out like a sore thumb.” Belemnite fossils found in Wyoming (and there are large quantities of them) measure 50 to 100 mm (2 to 4 in) long and 10 to 20 mm wide. “With a diameter reaching ~60 mm at the anterior end, these rostra are the thickest yet known for belemnites,” write belemnites expert Alexey Ippolitov and colleagues. The specimens are a bit broken up, but based on what remains, researchers estimate that Wyoteuthis The rostrum was between 160 and 175 mm long. “In other words, Wyoteuthis was a ‘fat’ but rather short squid,” the team writes. Existing methods for calculating the total length of a belemnite, arms and all, suggest that Wyoteuthis was between 55 and 60 cm (22 to 24 in) long, from the tip of its mantle to the end of its arms. But, the researchers add, “the size of the rostrum does not automatically indicate a large size of the animal and a high position in the trophic pyramid.” The researchers believe that its rarity could be the result of a narrow ecological specialization: perhaps it was picky about its prey or the type of habitat in which it lived. “Wyoteuthis linsterorum is a thick and peculiar belemnite, rarely seen in the Redwater Shale member of the Sundance Formation,” they note. It was part of the family Megateuthididae, which includes Megateuthis, the largest known belemnite, a group that had a very good run after the Toarcian extinction, when the ocean lost massive amounts of oxygen. Creatures that are more resistant to change can thrive under these circumstances, and cephalopods are especially known for that ability. But then, in the Middle Jurassic, most megathutidid lineages became extinct, overtaken by other belemnites. The researchers say Wyoteuthis is likely “a burly survivor of a lineage that would otherwise be lost to the depths of geological time.” The research has been published in Papers in Palaeontology. ScienceAlert stories are written, fact-checked and edited by humans, never generated by AI. Don’t miss any stories, subscribe here.Related news
