A new species of marine reptile from the Cretaceous period has been identified from fossils found on the eroded banks of the Volga River.
Artist’s reconstruction of Luskhan itilensis. Image credit: Andrey Atuchin.
Pliosaurs, also known as pliosauroids, were a type of short-necked plesiosaur: marine reptiles built for speed compared to their long-necked cousins.
These creatures were not dinosaurs, but distant cousins of modern turtles.
They had four large flippers, large heads, extremely powerful jaws and enormous teeth, and hunted fish, cephalopod mollusks and other marine reptiles.
They lived between 220 million years ago (Triassic period) and 70 million years ago (Cretaceous period) and were mostly found in the prehistoric seas that covered modern-day Europe.
The newly-identified pliosaur, named Luskhan itilensis, lived during the Hauterivian age of the Early Cretaceous, approximately 130 million years ago.
Its near-complete skull was found almost 15 years ago by Ulyanovsk State University paleontologist Dr. Gleb Uspensky.
“The skull of Luskhan itilensis is about 5 feet (1.5 m) in length, indicating a large animal. But its rostrum is extremely slender, resembling that of fish-eating aquatic animals such as gharials or some species of river dolphins,” said Dr. Valentin Fischer, a researcher with the University of Liege, Belgium.
“This is the most striking feature, as it suggests that pliosaurs colonized a much wider range of ecological niches than previously assumed.”
“By analyzing two comprehensive datasets that describe the anatomy and ecomorphology of plesiosaurs with cutting edge techniques, we revealed that several evolutionary convergences took place during the evolution of plesiosaurs, notably after an important extinction event at the end of the Jurassic (145 million years ago),” the researchers said.
“The new findings have also ramifications in the final extinction of pliosaurs, which took place several tens of million years before that of dinosaurs.”
“Indeed, the results suggest that pliosaurs were able to bounce back after the latest Jurassic extinction, but then faced another extinction that would — this time — wipe them off the depths of ancient oceans, forever.”
The paper naming the new pliosaur was published today in the journal Current Biology.
_____
Valentin Fischer et al. Plasticity and convergence in the evolution of short-necked plesiosaurs. Current Biology, published online May 25, 2017; doi: 10.1016/j.cub.2017.04.052
