Triassic kraken

The supposed "Kraken" beak found by Mark McMenamin. Despite claims of it and its owner's giant size, the scale bar shows it is under 5cm.

The Triassic kraken is a gigantic squid or octopus like creature hypothesized by palaeontologist Mark McMenamin to have existed in the Triassic era, in Nevada, the United States.

Background

A large fossil site in Nevada was found containing various bones of Shonisaurus, a very large ichthyosaur. Analysis revealed they died in deep water, and their bones were arranged in a curious, unnatural pattern. In 2011, McMenamin and Dianna Schulte argued that the pattern of the bones was the work of a giant "Triassic kraken" which was making a portrait of its own tentacles.

McMenamin held another talk on the subject in 2013. This time, he used what he claimed was a recently found Triassic giant squid beak as evidence. He hypothesized that the animal, in life, was the size of a school bus (i.e. 10-30 meters).

Veracity

Though there was significant media hype and coverage of the supposed "Kraken artwork" discussed by McMenamin, scientific reception of the theory was cool at best. Many contemporaneous scientists have pointed out that McMenamin glosses over numerous more likely conservative theories as to why the ichthyosaurs died or why the bones are arranged in that pattern in favor of his "Kraken".

Contrary to what he claims, cephalopods do not create "artwork" outside of their dens like the supposed kraken: the debris collected around the entrances to octopus dens is randomly scattered and serves as camouflage for the entrance. Most scientists agree that the bone formations were caused by weathering, as Dave Fastovsky points out:

“

There’s a simpler explanation. Ichthyosaurs die. They sink to the bottom, where scavengers get to work stripping their skeletons of flesh. The tendons and ligaments that held the vertebrae together rot away or are eaten. What happens to that vertebral column? Well, the first thing that happens is it sort of starts to fall over almost like a row of dominoes. The weird tiled position actually appears to be the most stable position for those falling dominoes to end up at rest. A perfectly reasonable, pedestrian, coherent story emerges that doesn’t require wholesale invention of what is unknown or unprecedented

”

Large Shonisaurus and Shastasaurus species compared in size to an average human (Source).

In 2013 McMenamin claimed he was in the possession of the beak of the Triassic Kraken. This fossil has been shown to be under 5cm long, which does not match with even the conservative estimate he gave in his follow up talk of "school bus size". Regardless, even the gigantic 100 foot specimen he proposed in 2011 would have a hard time taking down an adult Shonisaurus like the ones found in Nevada: Even at 45 feet the modern-day giant squid is only around 700 pounds, while an adult Shonisaurus is 20-30 tonnes, and Shonisaurus was a squid hunter, analogous to a beaked or sperm whale. More likely explanations for the massed dead Shonisaurus specimens include beaching and accumilation of remains over time.