Blasts from the Past: Mosasaurs, Baryonyx, Zeuglodons, and Ichthyosaurs

Artist’s rendering of a Baryonyx, a prehistoric sea predator. (Troy Therrien)

In 1780 a dinosaur jaw was discovered in a mine near the Maas River in the Netherlands. Napoleon had it carted to France in 1795 where it became the object of much discussion for years, as scientists argued whether it was from a toothed whale, alligator, or lizard. Its resemblance to lizards was finally officially recognized in 1822 when it was given the genus name mosasaurus, which means “Maas River lizard.”

Mosasaurs could reach 40 feet or more in length. They looked very similar to Coleman and Huyghe’s drawing of the classic sea serpent” with a long, alligator-like jaw and strong flippers on a mostly tubular body. One artist’s interpretation of the mososaur known as tylosaurus also shows it with a scalloped dorsal (back) fin, which could provide another explanation of the short humps sometimes seen trailing behind a monstrous head. It lived in a sea that once covered the midsection of North America, and it ate diving birds, fish, and other mosasaurs. Tylosaurus was supposed to have died out 65 million years ago. But did it? The state of Utah has become known for sightings of monsters in Bear, Sevier, Fish, Utah, and Great Salt Lakes. Living things can be tenacious. And Natural History magazine has noted several paleontologists maintain that “snakes and mosasaurs are more closely related to each other than either group is to any other group of lizards.” In that case, calling a mosasaur a “sea serpent” does not seem such a stretch.

Baryonyx was another gator-jawed creature whose fossil skeleton was first discovered in 1983 in a clay pit in the United Kingdom. The lizard-like bones were found about three-quarters complete and would have measured 20 feet long. Evidence shows that Baryonyx was a fish-eater and probably used its oversized, deadly claws to hook its prey. The odds may be less likely that this killing machine has survived until the present without detection, since it would probably wreak noticeable havoc wherever it popped up. Baryonyx would surely be termed a “water monster” if encountered by some unwary fisherman today.

Another ancient species that ranks high on the possible relict popularity scale is not a reptile at all. Zeuglodon was a primitive, toothed whale that lived around 25 million years ago and could reach lengths of 70 feet. Zeuglodon did not look much like modern whales; it was originally named Basilosaurus because it resembled a lizard in some ways. But its later placement in the whale category has also been disputed because it has many characteristics of the seal family, or pinnipeds, as well. Author Dr. Roy P. Mackal has proposed that an unknown creature observed snatching a duck from a watery surface near Vancouver in 1934 matched what we know of Zeuglodons perfectly. “Even a casual comparison,” says Mackal, “. . . reveals the striking agreement with the description of the observed animal.”

The observed animal, according to the duck hunters who saw it, was about 40 feet long and two to three feet wide with a tapering body and a three-foot-long head. The head was described as horse-like, though lacking ears or nostrils, and as dark, grayish brown marked with one horizontal, dark stripe. This is a description that could match many water creature sightings from around the world, making Zeuglodon a prime suspect in the relict category.

Zeuglodon was also tapped to explain one of the most famous sea serpent sightings ever—that of the H.M.S Daedalus in August 1848, off St. Helena, a British island in the South Atlantic Ocean. That monster was described by one witness as “a blunt-nosed animal with a neck carried about four feet above the water, which was so long as to present the appearance of a serpent . . . Two or three years after this, on reading the description of a Zeuglodon cetoides . . . it struck me that the animal seen from the Daedalus may have been a descendent of the order to which Zeuglodon belonged; and I have ever since watched with interest for reports of the ‘great sea-serpent.’ ”

While there are probably innumerable prehistoric creatures that resembled traditional sea serpents, with many still possibly undiscovered, one other is often inserted into the lineup of suspected sea monsters: the ichthyosaur, which means “fish-lizard.” The first ichthyosaur skull was found and recognized off Southern England in 1811. Ichthyosaurs varied in size and appearance from three to over 30 feet long, and from early, eel-shaped species to later versions that looked like dolphins with long, sharp beaks full of teeth. Ichthyosaurs, like mosasaurs, were reptiles, and needed to come to the surface to breathe. But they were more ancient than the mosasaurs, making it even less likely that some of them might have survived until present times.