A Chunky Squid Relative Once Lived in Wyoming's Ancient Sea
Fossils dug from a Wyoming rock formation belong to a squid-like animal that was wider around the middle than any of its relatives found there before.
About 160 million years ago, the land that is now Wyoming lay under an inland sea connected to the Pacific Ocean. One of the animals swimming in it was a squid-like creature with a body far thicker than that of its relatives. It is the chunkiest member of its group ever found in the rocks there, and it now has a name.
A squid from Wyoming
The new species is called Wyoteuthis linsterorum. The first part of the name means "a squid from Wyoming." It belongs to a group called belemnites, which are extinct relatives of today's squid and octopuses. Its fossils came out of the Sundance formation, a set of rocks dating to about 160 million years ago, and then sat in museum collections until paleontologists recognized that they were looking at something new. The study appeared in Papers in Palaeontology and was led by Alexey Ippolitov, a paleontologist at the University of Wellington.
The chunkiest one yet
Belemnites had turned up in this formation before, so the animal itself was not a surprise. Its size was. The measurement that stood out was the girth of its rostrum, a bullet-shaped shell that protected the soft parts of the body. That shell measured 2.4 inches around, making this the chunkiest belemnite ever found. Even so, the researchers estimated that the whole animal was no more than 18 inches long.
Using CT scanning, the team also looked inside at two other hard parts: the chambers the animal used to control its buoyancy, and the cup that joined the pieces of its shell. All three structures set it apart from every known species. Jessica Lippincott, a paleontologist with the Wyoming Dinosaurium Project and an author of the study, said that after years of collecting the common Pachyteuthis belemnites in Wyoming, this one was unlike anything she had ever seen.
Why so stocky, and how it ended
Why the animal grew so wide is still a mystery. One idea is that being big helped it hunt. "A possible explanation is that their relatively large size gave them an advantage when hunting co-occurring smaller belemnites of the genus Pachyteuthis," Ippolitov said. In other words, it may have preyed on smaller, more delicate relatives that lived in the same sea.
Whatever the advantage was, it did not last. Belemnites were wiped out at the end of the Cretaceous, at the same time the large dinosaurs perished. The chunky squid of Wyoming disappeared with them, leaving only its shell in the rock for someone to find millions of years later.