Wednesday, January 21, 2015

Species That Don't Get Enough Publicity #10: Tusoteuthis

Giant squids are iconic animals. Squids by themselves are intelligent, powerful, and alien-looking. Giant squids give grandeur, epic scale, and mystery, having not been seen in their natural habitat until 2004. Although not as long as a bootlace worm or as heavy as a colossal squid, they have become legendary. Their corpses and fleeting sightings of their dying have created legends in places from Norway to Greece to Japan.  The Norse sailors and Vikings prayed for safety from the Kraken, a beast so powerful it is still part of modern popular culture.

Sadly, they don’t make many appearances in pop culture about prehistoria. And there’s a reason for that; they don’t fossilize. Octopus and squids are among the few mollusks that have lost their shell. All that’s left is the gladius or pen, a long bony structure supporting the body of the animal.  “Soft” cephalopods form the subclass Neocoleoidea, made of two groups-decapods and octopids. The first is a tiny Devonian animal, Boletzkyida. For the most part, they stayed small. Some orders only survive today with a single species, like the Ram’s horn squid  The first octopus date back to the Carboniferous, but so small it would only satisfy a Japanese child for a school lunch.

It was the Cretaceous that shows an exception. Recently, an Australian squid of the Cretaceous, Boreopeltis, was found at 6 feet long.   Earlier relatives from Germany only measured a few feet long at most, the largest the size of a human.  In 1898, W. N. Logan identified a 2-foot fossil from Kansas as a squid pen.   More squid pens were found from Kansas to Mantiboa, an area known to be the east coast of the Niobrara sea. The Niobrara sea, or Western Interior sea, existed in the Cretaceous period, cutting the continent in half.  Limestone and shale deposits across the Midwest show the wide variety of life.  While the marine reptiles and ammonite cephalopods of the area are iconic, famous, and well-known, the poorly-preserved squid and octpus are more obscure.  Logan called the giant pen Tusoteuthis longa, after the long gladius. It was, by far, the largest fossil cephalopod since the Devonian extinction.

More pens have been found since then, some intact, some fragmented. One pen was 6 feet long. If it had the same proportions as Architeuthis, its modern counterpart, this would mean it was more than 30 feet long, one of the largest cephalopods ever.  That’s a big if, however. You see, the pen is far more similar in shape to that of the Vampire Squid, which is not a true squid but more related to the octopus; it even has 8 arms. Vampire squids today are reddish black with eyes that are blue in high light and red in low light, have a webbing between their tentacles, and are only about a foot long. They live in the very deep sea, eating floating carrion and small squid and fish, and emit dim light from their photophores and bioluminescent mucus.

So, it’s very likely Tusoteuthis would have had the same proportions, albeit not the same physical adaptations. Using those proportions, it would be 20 feet long and 10 feet wide. The pen, however, is much denser and stronger than the wispy ones of the vampire and giant squids. This suggests an animal that could swim at fast speeds. While the vampire squid is relatively sluggish and docile, enveloping prey with its webbed arms, the giant squid  is not. Architeuthis has been observed aggressively devouring smaller squid and stomach contents include fish, squid, and even sharks.  It’s probably an ambush predator-slowly swimming with its huge eyes scanning the blackness then swiftly descending on prey and grabbing them with its long tentacles.

Tusoteuthis, however, lived in a shallower sea, and its pen was very robust in comparison. This would mean shallow waters where it needed more muscle. The sea was full of predators and prey-fish and reptiles of all sorts took advantage of the rich plankton and plankton-eating prey.  It’s possible it was a fast, aggressive predator that ate large fish and sea reptiles.

It did have predators of its own-an immature pen was found embedded in the gullet of a fish. This fish, Cimolicthys, was a fast-moving predator superficially resembling a barracuda.  The specimen has the broken pen stuck in the ribcage near the shoulder and a piece puncturing its gills. So, by eating the squid, the fish choked on the pen and drowned. People die from choking on fishbones, but it appears that this fish choked in turn on a squid!

Another specimen has large punctures, indicating it was badly bitten. Only one predator was big enough to have inflicted the damage-the apex predator and America’s largest lizard of all time, Tylosaurus.  Tylosaurus teeth, toothmarks, and stomach contents have suggested that this mosasaur devoured any prey it could find, and no doubt even the biggest mollusk of the Mesozoic would not be a match for it.

Tusoteuthis might have had a sister species. A huge beak was discovered in the Japanese island of Hokkaido, a beak of similar dimensions to today’s giant squid.  It has been named Yezoteuthis after the ancient name of Hokkaido. The shape suggests a true squid, but no gladius or impression has been found. Hopefully, more of both these kraken will be found!

I’m afraid there’s not much else to say about Tusoteuthis and so this is very short blog this time. It has made a single appearance in the IMAX film Sea Monsters, making a cameo as one of the many denizens of the Western Interior sea, simply swimming through the blue. You can find Tusoteuthis fossils in the Sternberg Museum in Hays, Kansas, University of Colorado Museum in Boulder, Colorado, and the Canadian Fossil Discovery Centre in Morden, Mantiboa.  The reason this species is so obscure is because we only have the gladius.  Mollusks don’t have skeletons, after all, so it would take an impression in the sediment, as well as the beak and pen, for a fossil cephalopod to be best understood. Like its modern counterpart, it is enigmatic, mysterious, powerful, alien, and fascinating.

So anyway, Hollywood, give this guy a break. Museums, put him on display. Toy companies, here’s a new fresh face. Authors, think about the crap you’re writing and how this genus could perk up the place. And remember, shop Tusoteuthis where you work or play.
Here’s some great pages on it, especially Michael Everhart’s excellent Oceans of Kansas website


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