The chunkiest squid cousin ever found hid in Wyoming for 160 million years — and its family was supposed to be long gone

Belemnites were squid-like sea creatures whose hard internal skeletons, called rostra, are among the most common fossils in Wyoming — usually slim and bullet-shaped, just 1 to 2 centimetres across. Two rare fossils from the Sundance Formation are nothing like that. Their rostra measure about 10 centimetres long but up to 6 centimetres (2.4 inches) across, making the new species, Wyoteuthis linsterorum, the thickest belemnite ever identified — the living animal was probably about 60 centimetres (2 feet) long. What matters most is its family: Megateuthididae were thought to have mostly disappeared millions of years earlier, yet this animal was still swimming in the ancient Sundance Sea about 160 million years ago. The find, published in Papers in Palaeontology, suggests the family survived in a refuge in the northeastern Pacific that no one knew existed.