Giant Squid vs. Mosasaur

View Images
In this University of Kansas Museum of Natural History mural, the Cretaceous squid Tusoteuthis tussles with a mosasaur. Only, there’s no evidence that such battles ever took place. Image: Courtesy Mike Everhart.

There are giant squid in Kansas. They are not pickled museum specimens rescued from a Newfoundland beach, nor, b-movie schlock like Eye of the Beast aside, are they monsters that found their way into freshwater lakes. Truth be told, the big squid have been dead for about 80 million years. What little remains of them is petrified in the rock. But in their heyday, these huge cephalopods lived and died alongside equally fantastic marine reptiles that ruled North America’s shallow inland sea.

Prehistoric squid are rare fossils. Unlike their hard-shelled cousins the ammonoids, ancient squid lacked the hard, coiled shells that were so amenable to preservation. Even then, the soft parts of shelled cephalopods rotted away, leaving us with only an outline of what the mollusks were like in life. Only cases of truly exceptional preservation can provide researchers with a near-complete view of primordial cephalopods.

All the same, paleontologists have been able to identify the teuthids of different eras thanks to certain chitinous hard parts of squid bodies. The nipping, bird-like beak is one squid organ resilient enough to enter the fossil record, and the other, called a gladius, is at the core of the squid’s body. This structure – vaguely spoon-shaped, with a rod leading into a rounded expansion – supports the mantle of the squid and anchors some of the animal’s muscles. It’s this bit of internal scaffolding that has let paleontologists track the giant squid of Kansas.

View Images
The Western Interior Seaway, circa 75 million years ago. Image: R. Blakey, from Wikipedia.

In 1898, as part of a massive review of Cretaceous fossils found in Kansas, paleontologist William Newton Logan surveyed the various marine invertebrates that evidently swum through a long-vanished seaway. While dry and landlocked now, the “Wheat State” was submerged for much of Cretaceous time.

Starting about 130 million years ago, and lasting almost to the very end of the Cretaceous, the ocean spilled over the landmass to create two subcontinents – the dinosaurs and other creatures on the western slice, called Laramidia, were separated from their eastern kin on Appalachia by a sea filled with sharks, plesiosaurs, mosasaurs, toothed birds, and other wondrous sea creatures. Of course, numerous forms of marine invertebrates were often food for these more famous and charismatic aquatic animals, including what Logan identified as huge squid.

The fossils Logan cataloged were roughly 90 to 70 million years old, and he divided his list according to the geologic formations in which they were found. From the fossils found in the Niobrara shale, now understood to be around 82 to 87 million years old, Logan described a previously-unknown genus of squid he called Tusoteuthis. The key fossil was a gladius, or pen, collected by H.T. Martin near the Smoky Hill River. Part of the structure’s shaft was missing, but the whole thing measured a little more than 20 inches long. While Logan did not speculate on the size of the entire squid itself, such a large gladius indicated an even longer cephalopod, especially if the squid had long tentacles that extended past the muscular arms.

But how big did Tusoteuthis actually get? In a sea full of sharp-toothed marine reptiles and huge fish, size most certainly mattered. Frustratingly, though, all we really know of Tusoteuthis comes from their fragile, fossilized pens found in Kansas, North Dakota, and elsewhere along the path of the vanished seaway. No one has ever found a pancaked impression of a Tusoteuthis body to fill out the rest of the details, and the biggest near-complete pens found so far are about six feet long. According to Western Interior Seaway expert Mike Everhart, who runs the richly-detailed Oceans of Kansas website, Tusoteuthis may have reached about 25 feet in length. That’s not quite as big as the 40-foot-plus giant (Architeuthis dux) and colossal (Mesonychoteuthis hamiltoni) squids that jet through today’s ocean depths, but still quite large.

View Images
An updated view of Tusoteuthis by D.Bogdanov. Image: Wikipedia.

Nevertheless, we don’t really know whether Tusoteuthis was any longer or shorter than the 25 foot estimate. Our picture of the Cretaceous squid depends on how we restore its soft tissues, and that’s constrained by where Tusoteuthis falls in the teuthid evolutionary tree. While it’s easy to think that Tusoteuthis was more or less like today’s giant squid Architeuthis, Everhart suspects that the Cretaceous form is more closely related to the bizarre, deep-sea Vampyrotheuthis. This translates to a relatively squat squid with shorter arms than previous, slimmer versions.

Let’s run with the hypothesis that Tusoteuthis was about 25 feet long, though. That’s a big squid, and it’s certainly tempting to think of the cephalopod wrapping its arms around the lizard-like mosasaurs and long-necked plesiosaurs, dragging the air-breathing reptiles into the abyss. Geologist Mark McMenamin tapped into this tantalizing imagery last year when he presented his bullshit idea that a hyper-intelligent Triassic squid drowned giant ichthyosaurs and rearranged the bones of the deceased “fish lizards” into a self portrait. McMenamin had no evidence – no body impression, gladius, or other trace of Mesozoic squid – but news services enthusiastically regurgitated his unsubstantiated claims of the artistic Kraken. Who wouldn’t love a story about real-life leviathans tearing at each other in the prehistoric deep? The famous giant squid vs. sperm whale exhibit at the American Museum of Natural History has sparked visions of real-life abyssal battles for decades, and a skirmish between a prehistoric squid and the likes of the mosasaurs would have been even more spectacular. Using the old, slender vision of Tusoteuthis, the University of Kansas Museum of Natural History even commissioned a painting of such a conflict for their exhibits.

Only, there isn’t any evidence that Tusoteuthis captured and killed the marine reptiles of its time. Granted, such traces would be rare. Like other squid, Tusoteuthis fed on flesh rather than crunching into bone, and I have no idea if anyone has ever found a squid bite mark in the fossil record. But there’s no reason to think that the squid targeted dangerous prey as large, if not larger, than itself. Tusoteuthis was undoubtedly a predator of smaller game such as fish and other cephalopods. If the squid ate marine reptiles at all, it probably only snarfed up baby ones unlucky enough to blunder across the larger cephalopod.

There’s solid evidence that Tusoteuthis was a frequent victim of other Western Interior Seaway inhabitants, though. In addition to squid pens bearing bite marks from unknown predators, one particularly unlucky fish appears to have died in the act of swallowing a Tusoteuthis. Arms trailing out of the gluttonous fish’s mouth, the fossil hints,  the squid filled its assailant’s tract so completely that water could no longer pass through the vertebrate’s gills. A final moment of payback for the giant squid of North America’s vanished sea.