More than 72 million years ago, the western Pacific Ocean was home to some of the most ferocious marine predators in history.
regarding bus sizethis giant air-breathing creature was not a mammal, despite its nature. warm blood. And yet, it wasn’t even a crocodile. similar shaped head. Instead, it belonged to a group of now-extinct sea lizards that had binocular vision, huge paddle-like limbs, a long, powerful tail rudder, and possibly a dorsal fin.
Japanese scientists call it Wakayama’s “Blue Dragon” after the location where it was discovered and the mythical creature of Japanese folklore.
The nearly complete skeleton of this extinct animal was discovered along the Arida River in Wakayama Prefecture in 2006 by paleontologist Akihiro Misaki of the Kitakyushu Museum of Natural History and Human History. It took five years to extract the bones from the stone in which they were buried.
Official descriptions of the 6-meter-long creature currently classify it as an entirely new species of mosasaur. Megapterygius wakayamaensis.
Figuring out how they swam and hunted has proven to be quite difficult.
“From fish to penguins to sea turtles, there are no modern analogues with this type of body morphology.” To tell Takuya Konishi, a paleontologist at the University of Cincinnati, says: “Nobody has four large fins that they use in conjunction with the caudal fin.”
mosasaurus They are some of the largest predators of all time, Extends up to 17 meters In some cases. For about 20 million years, these fearsome beasts reigned supreme over the oceans and are the last great marine lizards.
Your jaw may be shattered or your teeth may be cut. accept almost anything, from shellfish to turtles and sharks.They are even ate other animals of the same species.
Konishi, an expert on giant marine lizards, thought he understood mosasaurs until he focused on Wakayama’s Blue Dragon.
The paddle-shaped flippers, especially the dorsal flippers, are unusually long compared to other mosasaurus fossils found in other parts of the world, including New Zealand, California, and Morocco.
The spinal spines also look different, resembling a dolphin or porpoise.
Cetaceans like dolphins and porpoises have a dorsal fin just behind their center of mass, which gives them additional stability when swimming.
Although it is still very much at the hypothetical stage, scientists studying the M. wakayamaensis It is thought that this mosasaurid also had a dorsal fin.
Based on the fact that cetaceans with long fins not only navigate but also use their limbs to maneuver while swimming, the Japanese research team suspected that the green lizard also used its front fins for similar reasons. I’m guessing that there isn’t.
The dorsal fin, which is absent in modern cetaceans, may have been used for diving and surfacing.
The tail was probably the driving force.
By comparison, plesiosaurs, ancient swimming reptiles that lived alongside mosasaurs, used their flippers rather than their tails for propulsion.
scientist think Most plesiosaurs could not compete with mosasaurs as predators, but it is unclear whether this has anything to do with their different swimming abilities.
“The question is how were all five of these hydrodynamic surfaces used? Which ones were for steering and which ones for propulsion?” explain Mr. Konishi.
“This opens up a whole can of worms that calls into question our understanding of how mosasaurs swim.”
This study Journal of Systematic Paleontology.