Giant sea lizard Khinjaria had teeth like daggers

Paleontologists have unearthed a fascinating new species of marine lizard that thrived just before the dinosaurs’ reign came to an end. The species, known as Khinjaria acuta, possessed formidable dagger-like teeth, painting a picture of a vastly different marine ecosystem than what exists today. 

This ancient ocean was populated by a plethora of large predatory creatures that fed on sizable prey, in stark contrast to contemporary ecosystems where a limited number of apex predators, such as the great white shark, the orca, and the leopard seal, hold dominion.

Giant marine lizards 

Khinjaria acuta was a mosasaur, a group not directly related to dinosaurs but rather to giant marine lizards, akin to today’s Komodo dragons and anacondas. These creatures dominated the seas about 66 million years ago, contemporaneously with the Tyrannosaurus and Triceratops.

The newly discovered species boasted powerful jaws and long, dagger-like teeth, making it a fearsome predator within the rich and varied predator community in the Atlantic Ocean near Morocco. 

Khinjaria fossils

The findings are based on the examination of a skull and skeletal parts unearthed in a phosphate mine southeast of Casablanca, involving a collaborative effort from researchers at the University of Bath, UK, the Marrakech Museum of Natural History, the Museum National d’Histoire Naturelle (NMNH) in Paris, France, the Southern Methodist University in Texas, USA, and the University of the Basque Country, Bilbao.

Extraordinary diversity 

Dr. Nick Longrich, from the University of Bath, who led the study, remarked on the exceptional predator diversity, noting that several species exceeded the size of a great white shark. Moreover, each species showcased different dental adaptations, indicative of varied hunting strategies. 

“Some mosasaurs had teeth to pierce prey, others to cut, tear, or crush. Now we have Khinjaria, with a short face full of huge, dagger-shaped teeth. This is one of the most diverse marine faunas seen anywhere, at any time in history, and it existed just before the marine reptiles and the dinosaurs went extinct.”

Asteroid impact 

This diverse marine life existed on the brink of cataclysm, just before an asteroid impact in the Yucatan Peninsula ushered in a mass extinction event. The event obliterated dinosaurs and led to the diversification of surviving mammals, birds, and lizards on land, while similarly transformative effects occurred in the oceans. 

The aftermath saw the disappearance of mosasaurs, plesiosaurs, and giant sea turtles, making way for the evolution of whales, seals, and certain fish species. However, the post-impact ecosystem markedly differed from its predecessor.

Ecosystem structure 

“There seems to have been a huge change in the ecosystem structure in the past 66 million years,” Longrich added, highlighting the unusual diversity and abundance of apex predators in the Late Cretaceous compared to modern marine communities, where large predators are fewer.

“The Phosphates of Morocco deposit in a shallow and warm epicontinental sea, under a system of upwellings; these zones are caused by currents of deep, cold, nutrient-rich waters rising towards the surface, providing food for large numbers of sea creatures and, as a result, supporting a lot of predators. This is probably one of the explanations for this extraordinary palaeobiodiversity observed in Morocco at the end of the Cretaceous,” said senior author Nathalie Bardet, a paleontologist at NMNH.

Khinjaria, a new mosasaur

Study co-author Nour-Eddine Jalil, a paleontologist at the same institution, further explained the significance of the Moroccan phosphate deposits: “The phosphates of Morocco immerse us in the Upper Cretaceous seas during the latest geological times of the dinosaurs’ age. No deposit has provided so many fossils and so many species from this period.”

“After the ‘titan of the seas,’ Thalassotitan, the ‘saw-toothed’ mosasaur Xenodens, the ‘star-toothed’ mosasaur, Stelladens and many others, now there is Khinjaria, a new mosasaur with dagger-like teeth. The elongation of the posterior part of the skull which accommodated the jaw musculature suggests a terrible biting force,” he concluded.

The study is published in the journal Cretaceous Research.

Image Credit: Andrey Atuchin

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