80 million-year-old sea monster jaws filled with giant globular teeth for crushing prey discovered in Texas

Fossils from a huge, rare mosasaur with giant globular teeth have been unearthed in Texas, a new study reveals.

The two adult jaw fragments provide insights into the lifestyle of Globidens alabamaensis, which may have reached lengths of up to 20 feet (6 meters). The blunt teeth that line the jaws demonstrate the brute force the mosasaurs brought to bear on their prey.

"These structures with their mushroom shape are great for impact attacks — for shell crushing. If something is getting away and you shatter it, that's kind of it," Bethany Burke Franklin, a marine paleontologist and educator at Texas Through Time fossil museum in Hillsboro, told Live Science. Franklin, who specializes in marine reptiles, was not involved in the study.

During the Late Cretaceous period (100.5 million to 66 million years ago), many iconic marine predators such as the dolphin-like ichthyosaurs and long-necked plesiosaurs succumbed to a changing climate and ensuing alterations to the marine ecosystem. Mosasaurs became the dominant predators in the shallow seas of the epoch, assuming niches once occupied by their better-known predecessors. These reptiles rapidly diversified, filling multiple niches in the volatile and prey-rich environment.

G. alabamaensis was discovered in 1912, but only a handful of near-complete specimens of this mosasaur have ever been unearthed. Most fossil evidence consists of teeth and small jaw fragments. Four additional Globidens species have since been described.

Related: 'Closer than people think': Woolly mammoth 'de-extinction' is nearing reality — and we have no idea what happens next

While most mosasaurs boasted a formidable array of dagger-like teeth, Globidens evolved blunt, rounded teeth that were suited to crushing the shells of turtles, ammonites and bivalves. The Western Interior Seaway, which bisected what is now North America during the Late Cretaceous, would have provided G. alabamaensis with a wide variety of shelled prey.