In 1764, a Dutch army lieutenant encountered something unexpected and strange in the hills of a limestone mine, near the modern city of Maastricht. The find was a giant skull of a prehistoric reptile, which at the time was described as a “large breathing fish”, something similar to a whale, but with very sharp teeth. They later named it Mosasaurus, meaning “lizard of the Meuse”, as it was discovered near the Meuse River. Since then the family MosasaursIt grew and we found all sorts of remains scattered across Europe, Asia, North America, South America and even Antarctica.
Mosasaurs are a large group sea predators which in many cases easily exceeded ten meters in length and became genuine kings of the chalk ocean for millions of years.
However, no matter how much we think we know about dinosaurs… sooner or later a new fossil comes along that surprises paleontologists with unknown and fascinating characteristics. This is exactly what happened just a few days ago along the Aridagawa River, in Wakayama Prefecture, Japan, where a group of researchers discovered almost complete remains of a new species of mosasaurus, never seen before.
This discovery was published in the Journal of Systematic Paleontology, and scientists called it “Megapterygius wakayamaensis“, a term that means “large winged” reptile due to its rear fins, which appear to be unusually large, while wakayamaensis refers to the Japanese prefecture in which it was found. Because scientific names are often confusing and difficult for the general public to remember, the researchers added a nickname for the new reptile and named it Wakayama Soryu, a reference to Soryuwhich is in Japanese mythology blue water dragon.
In 2006, paleontologist Akihiro Misaki was looking for ammonite fossils along the banks of the Aridagawa River when he came across a huge black vertebra. He immediately forgot about searching for shellfish and concentrated on this strange piece. It turned out to be one of the most complete mosasaurus skeletons ever found, and the remains included an impressive skull, as well as a series of cervical and dorsal vertebrae with more than 40 vertebrae, paired ribs, right and left front fins, and a left rear fin. . Of course, carefully extracting all these pieces, correctly assembling the huge puzzle, conducting exhaustive research and providing an adequate description is not an easy task, and in this case, it took paleontologists almost 17 years since Misaki found that first vertebra.
A full view of the discovered remains shows us powerful sea lizardfrom the size of a white sharkwhich had very long rear fins and large dorsal fin, similar to the dorsal fin of a killer whale. These qualities made this “blue dragon” a formidable, fast and precise predator when hunting in the waters of what would now be the Pacific Ocean, about 72 million years ago.
This mixture of shark and killer whale is something unprecedented, and experts themselves admit that “there is no modern analogue with this type of body morphology, from fish to penguins or sea turtles. “No animal that we know of has four large fins, which they use in conjunction with a caudal fin.”
“I thought I knew mosasaurs pretty well,” explains Takuya Konishi, lead author of the published study, “but we soon learned that this was something we had never seen before.”
ALSO VIDEO: Tyrannosaurus rex skeleton sold for $6.1 million
Konishi, Takuya et al. “New derived mosasaurine (Squamata: Mosasaurinae) from southwestern Japan reveals unexpected postcranial diversity among hydropedal mosasaurs.” Journal of Systematic Paleontology (2023) DOI: 10.1080/14772019.2023.2277921.
Harry Baker: “72-million-year-old ‘blue dragon’ found in Japan is unlike anything we’ve ever seen, experts say” Live Science (2023)