Paleontologists have described an unusual new species of mosasaur based on a fossilized partial jaw and associated tooth crowns from phosphatic deposits at Sidi Chennane, Oulad Abdoun Basin, Morocco.
The newly-discovered mosasaur swam in the Late Cretaceous seas of Morocco, approximately 67 million years ago.
Dubbed Stelladens mysteriosus, the ancient reptile was around twice the size of a dolphin.
It had a unique tooth arrangement with blade-like ridges running down the teeth, arranged in a star-shaped pattern, reminiscent of a cross-head screwdriver.
Most mosasaurs had two bladelike, serrated ridges on the front and back of the tooth to help cut prey, however Stelladens mysteriosus had anywhere from four to six of these blades running down the tooth.
“It’s a surprise,” said lead author Dr. Nick Longrich, a paleontologist at the University of Bath.
“It’s not like any mosasaur, or any reptile, even any vertebrate we’ve seen before.”
No close analogues to the unique tooth morphology of Stelladens mysteriosus are known, either living or extinct.
It may have had an unusual and highly specialized diet, a specialized prey-capture strategy, or both.
“We have no idea what this animal was eating, because we don’t know of anything similar either alive today, or from the fossil record,” Dr. Longrich said.
“It’s possible it found a unique way to feed, or maybe it was filling an ecological niche that simply doesn’t exist today.”
“The teeth look like the tip of a Phillips-head screwdriver, or maybe a hex wrench.”
The teeth of Stelladens mysteriosus were small, but stout and with wear on the tips, which seemed to rule out soft-bodied prey.
The teeth weren’t strong enough to crush heavily armored animals like clams or sea urchins, however.
“That might seem to suggest it’s eating something small, and lightly armored — thin-shelled ammonites, crustaceans, or bony fish — but it’s hard to know,” Dr. Longrich said.
“There were…
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