A Tiny Swimming Dinosaur Has Recently Been Discovered

There are, as we know, some truly vast creatures on Earth. The largest contemporary animal, per the WWF, is the antarctic blue whale. While many of us are familiar with this fact, it's difficult to comprehend just how big these creatures are. According to the outlet, they can reach a preposterous 98 feet long.

By contrast, terrestrial animals (even the very biggest) are, relatively, much smaller. Guinness World Records reports that the largest land-based animal (living) award went to the African elephant, which is up to 12 feet, 1 inches (3.7 meters) tall. These are contemporary animals, though, and in terms of land-dwellers, much larger things roamed during the time of the dinosaurs.

Based upon the limited remains unearthed, the size of the Argentinosaurus is estimated to be up to 131 feet (40 meters) long, according to Britannica. It is, hypothetically, the largest land animal in the planet's history, just another example of those extraordinary, legendary, remarkable dinosaurs. We tend to find them so intimidating and impressive purely by virtue of their huge size, but they have other unique traits, too. Millions of years after their extinction, dinosaurs keep coming up with new ways to surprise us. No true dinosaur with specific adaptations for swimming had ever been discovered, conclusively, until this fascinating new find.

The deep-sea monsters of prehistoric times

Naturally, the oceans of millions of years ago were also inhabited by enormous, nightmarish, stunning species. The mosasaurs, for example, lived alongside the dinosaurs of the Cretaceous period, Live Science reports. They came before the likes of the fearsome megalodon and today's sharks as we know them, and were a very large and toothy group of marine predator species.

They were not, however, dinosaurs. Plesiosaurs, the BBC reports, were also wiped out in the mass extinction event of 65.5 million years ago. These marine creatures developed a bit of a claim to fame from the tale of the Loch Ness Monster, and the theory that Nessie itself may be a survivor. Though reptiles like dinosaurs, however, neither plesiosaurs nor mosasaurs qualify as true dinosaurs.

Pterodactyls, often depicted right alongside dinosaurs in artists' depictions, are not dinosaurs, either. Britannica explains that this is because the creatures' families (scientifically speaking) are different, as are crucial parts of their respective anatomies: Pterodactyls do not have a characteristic gap in their hips, for instance.

The dinosaurs of prehistory, then, tend to be considered as huge terrestrial creatures almost exclusively. There are all manner of exceptions to this, however, and a newly discovered (potentially) swimming dinosaur species is just one more example.

The fascinating Natovenator polydontus

While the most familiar and iconic dinosaur species today are the vast, towering ones, they came in a range of sizes and shapes. In the December 2022 study "A non-avian dinosaur with a streamlined body exhibits potential adaptations for swimming" from Sungjin Lee et al (via Communications Biology), we're introduced to a new dinosaur species, which was discovered in the Gobi Desert. The species, the scientists report, was named Natovenator polydontus.

Per Smithsonian Magazine, this name means "many-toothed swimming hunter." Though this new species didn't boast the tremendous size of Argentinosaurus, its adaptations to life on the waves are, perhaps, just as extraordinary.

The study states: "This new taxon exhibits anatomical characteristics very similar to the aquatic adaptations in Halszkaraptor. More importantly, the configuration of its articulated dorsal ribs indicates that it had a dorsoventrally flattened and streamlined body." This is so very significant, the scientists go on, because it represents "the first compelling evidence of a streamlined body in a non-avian theropod dinosaur."

Features such as the creature's considerable neck are similar to those of other species known to have aquatic lifestyles (the aforementioned plesiosaurs among them). The streamlined body, Smithsonian Magazine adds, is a feature that seems to be exclusive to this small (around 1 foot in length) dinosaur, which had a body suited to hunting elusive aquatic prey.

Spinosaurus and other supposed water-venturers

Halzkaraptor, it seems, was discovered in 2017. In the study "Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs" from Andrea Cau et al (via Nature), the biological significance of Halszkaraptor escuilliei is discussed. The scientists reported that this fascinating specimen "coupled the obligatory bipedalism of theropods with forelimb proportions that may support a swimming function, and it developed postural adaptations convergent with short-tailed birds."

According to National Geographic, however, Halszkaraptor escuilliei was victim to that common paleontological pitfall: it was not well-preserved enough on discovery for an extensive study of its fossilized remains to be conducted. As is common in the field, then, its capacity as a swimmer, and its biological adaptations for doing so, are subject to debate.

Per Smithsonian Magazine, the hefty likes of Spinosaurus had equally hefty bones, a boon for a life spent at least partially in and around water. The March 2022 study "Dense bones allowed Spinosaurus to hunt underwater" from the University of Portsmouth (via Science Daily) corroborates this. Dr. Nizar Ibrahim concludes in the study, "... [E]ven the internal architecture of the bones is entirely consistent with our interpretation of this animal as a giant predator hunting fish in vast rivers, using its paddle-like tail for propulsion."

What Natovenator polydontus seems to have, though, are specific adaptations to support a semi-aquatic lifestyle. Hopefully, this little creature will provide a new insight into the world of dinosaurs.