![\"Wyoteuthis](\"https:\/\/cdn.sci.news\/images\/enlarge14\/image_15123e-Wyoteuthis-linsterorum.jpg\")
<\/a><\/p>\nWyoteuthis linsterorum. Image credit: Jason Poole.<\/p>\n
Belemnites swam in Jurassic and Cretaceous seas. They had soft bodies, but the part that fossilizes is the rostrum, a dense, pointed, calcite structure at the rear of the body, thought to have helped counterbalance the animal in the water.<\/p>\n
The fossilized rostra of Wyoteuthis linsterorum were discovered in the Sundance Formation, which records a shallow seaway that covered parts of the western United States about 160 million years ago (Late Jurassic).<\/p>\n
\u201cMost Wyoming belemnites are bullet-shaped measuring around 5 to 10 cm (2-4 inches) long and only 1 to 2 cm (0.4-0.8 inches) wide,\u201d said Victoria University of Wellington Ph.D. student Alexey Ippolitov and his colleagues.<\/p>\n
\u201cBy contrast, the newly discovered species had an unusually broad, barrel-shaped rostrum around 10 cm long but up to 6 cm (2.4 inches) wide, making it the thickest belemnite ever recorded.\u201d<\/p>\n
Because the fossils were packed with hardened sediment, the paleontologists used CT scans to study their internal structure.<\/p>\n
Along with the rostrum\u2019s shape, the angle of its internal cavity, and fine grooves and striations near its tip, this led them to assign the creature to the family Megateuthididae.<\/p>\n
Megateuthidid belemnites flourished in the Early and Middle Jurassic and were long thought to have gone extinct around the Bathonian age, about 166 million years ago.<\/p>\n
The researchers propose that Wyoteuthis linsterorum descended from an older genus called Brevibelus, and that it points to a previously unrecognized refuge for the family in the northeastern Pacific.<\/p>\n
\u201cI was deeply surprised to discover a fossil from such a well-studied group that differed so radically from anything previously known,\u201d Ippolitov said.<\/p>\n
\u201cAfter more than 200 years of paleontological research on belemnites, discoveries like this are exceptionally rare.\u201d<\/p>\n
The scientists suggest Wyoteuthis linsterorum may have been highly specialized, or may have lived mainly along the open-ocean shelf and only occasionally wandered into the Sundance Sea.<\/p>\n
\u201cAfter 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,\u201d said Jessica Lippincott, a paleontologist with the Wyoming Dinosaurium Project.<\/p>\n
\u201cIt goes to show that we are still finding new species of fossils all the time, and people who rockhound or collect invertebrate fossils can also contribute to science.\u201d<\/p>\n
\u201cThe find is incredibly rare, which might be due to some ecological adaptations to the environment at the time. Perhaps its rarity is a result of narrow specialization,\u201d said Dr. Dean Lomax, an honorary research fellow at the University of Manchester.<\/p>\n