Scientists have uncovered a new species of giant sea lizard mosasaur in Morocco that hunted other marine reptiles around 66 million years ago using its massive jaws and teeth like those of modern killer whales.
The giant marine lizard is called Thalassotitan atroxdescribed Wednesday in the journal Chalk researchgrew up to 9 m (30 ft) in length and are distant relatives of modern iguanas and lizards.
While some mosasaurs evolved to eat small prey such as fish and squid, and others crushed ammonites and clams, researchers, including those from the University of Bath in the UK, say the newly discovered evolved to prey on all the other marine reptiles.
The study suggests that Thalassotitan was an apex predator in its time, sitting at the top of the food chain.
At the bottom of the food chain were plankton that fed on nutrient-rich water from the depths of the ocean. Small fish fed on these plankton, which were then preyed upon by larger fish that fed mosasaurs and plesiosaurs.
These marine reptiles then became food for the giant, carnivorous Thalassotitan, scientists explain.
The giant marine reptile had an enormous skull measuring 1.4 m (5 ft) long, growing to nearly 9 m (30 ft) long, about the size of a killer whale.
Scientists say Thalassotitan had a short, broad snout and massive, conical teeth – similar to those of today’s killer whales – that allowed the reptile to grab and tear apart huge prey.
They found that the teeth of the giant reptile were often crushed and worn, suggesting that Thalassotitan attacked other marine reptiles, chipping, crushing and grinding its teeth as it bit into their bones and tore them apart.
Scientists also discovered the remains of Thalassotitans victims, including large predatory fish, a sea turtle, a half-metre-long plesiosaur head and the jaws and skulls of “at least three” different mosasaur species.
Scientists suspect that this prey was probably digested in Thalassotitan’s stomach before spitting out their bones.
“We cannot say for sure which animal species ate all these other mosasaurs. But we have the bones of marine reptiles killed and eaten by a large predator,” said study co-author Nick Longrich of the University of Bath.
Researchers also found evidence of injuries to Thalassotitan likely sustained in violent combat with other mosasaurs.
They say the new mosasaur lived in the last million years of the age of the dinosaurs, and unlike these, its contemporaries did not die after the extinction-driving asteroid impact, but flourished.
“The Thalassotitan was an amazing, terrifying animal. Imagine a Komodo dragon crossed with a great white shark crossed with a T rex crossed with an orca,” Dr Longrich added.
“Morocco has one of the richest and most diverse marine faunas known from the Cretaceous period. We are just beginning to understand the diversity and biology of the mosasaurs, said Nour-Eddine Jalil, a co-author on the paper from the Museum of Natural History in Paris.