Did a giant Kraken troll the Triassic seas, crushing ichthyosaurs and arranging their bones into pleasing patterns?
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This fossil discovered in Berlin-Ichthyosaur State Park in Nevada may be part of the beak
of an ancient giant cephalopod, such as an octopus or squid
[Credit: Mark McMenamin/LiveScience] |
It sounds like a Halloween tale, but researchers who first suggested the
existence of this ancient sea monster in 2011 say they now have more
evidence backing up their controversial theory. Not only have they
discovered a second example of strangely arranged bones, they've found a
fossil that appears to be the beak of an ancient squid or octopus.
"This was extremely good luck," said Mark McMenamin, a paleontologist at
Mount Holyoke College in Massachusetts who presented his findings here
Wednesday at the annual meeting of the Geological Society of America
(GSA). "This was finding the needle in the haystack, really."
Still, the Kraken theory has not gained widespread acceptance.
"A Kraken isn't really necessary," said David Fastovsky, a
paleontologist at the University of Rhode Island who attended
McMenamin's GSA presentation and penned a response to the evidence for
the Paleontological Society. "Everything can be explained by much less
exotic means."
Kraken controversy
McMenamin caused a splash when he and his colleagues first floated the
idea of the kraken at a GSA meeting in 2011. The evidence: A bizarre
arrangement of vertebrae of the ichthyosaur Shonisaurus popularis found
in Berlin-Ichthyosaur State Park in Nevada.
S. popularis was a school-bus-size, flippered marine reptile that lived
during the Triassic period, 250 million to 200 million years ago. The
bones of one of these ichthyosaurs were found in a strange linear
pattern. McMenamin and his colleagues argued that they were arranged
there by a giant cephalopod (an octopus or squid) playing with its food.
This hypothesis isn't quite as out there as it may seem: Modern
octopuses are known to manipulate bones, shells and other debris to form
middens, concealing the entrances to their dens. And today's giant
squid are known to battle it out with sperm whales, as evidenced by
tentacle scars found on whales and squid found in whale stomachs. The
bone arrangements could be the earliest evidence of cephalopod
intelligence, McMenamin said.
Still, the idea engendered a lot of backlash. Glenn Storrs, the curator
of vertebrate paleontology at the Cincinnati Museum Center, summed up
the skepticism to LiveScience in 2011, calling the weird bone
arrangement "circumstantial evidence."
The Kraken is back
Now, McMenamin has more. First, he argues, the arrangement of bones
could not have been made by natural processes such as currents or mud
compaction. The shape of the bones is such that there is "virtually
zero" probability that currents could have nudged them into that
arrangement, McMenamin told a crowded auditorium of geoscientists at
this year's meeting.
"You always go from a more ordered to a less ordered state, not the other way around," he said.
The organized state of the bones is the strongest evidence that some
intelligent creature arranged them, McMenamin told LiveScience. But
something else came up that has him convinced: A second example of the
weird bone pattern.
This one comes from an ichthyosaur fossil formerly on display at the
University of Nevada, Las Vegas Museum of Natural History. The fossil
had been laid out in the museum exactly as found in the field. The
exhibit is long gone now, but a curator passed a photo on to McMenamin.
"When I saw that photograph, basically my eyeballs popped out," McMenamin told LiveScience.
Next to the ichthyosaur was a "debris pile" of scattered bones that were
no longer in their proper place in the skeleton. And off to the side
was a double row of vertebrae in the same configuration as McMenamin and
his colleagues had seen in the original ichthyosaur remains.
The rib cage of the museum specimen shows damage, as if something —
perhaps the tentacles of a giant deep-sea monster? — had constricted
them in a bear hug.
"We think one plausible explanation of this is an attack on the icthyosaur by a much larger predator," McMenamin said.
A smoking gun?
Once he saw the museum photograph, McMenamin made a field expedition
back to Berlin-Ichthyosaur State Park, where he and his colleagues
combed through fossils weathering out of rock in search of more
cephalopod evidence. Almost unbelievably, they found it.
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One
scientist claims these vertebrae are from ichthyosaurs taken out by a
sea monster,
which then arranged the bones in a pattern [Credit: Mark
McMenamin/LiveScience] |
Among the fossils the team collected on their trip was a strange,
pointed object that McMenamin almost tossed, thinking it might be a
fish. But the fossil had un-fishlike fibers running through it, so he
hung on to it. Months later, he bought a modern Humboldt squid beak off
eBay for $60 and compared it to the ancient fossil.
The fracturing patterns and fibers matched. McMenamin thinks he has the
beak of an elusive Triassic kraken. The fossil "shows that indeed there
were giant cephalopods in this area," he said.
Or Not ... ?
If the fossil is indeed a beak, it's too fragmentary to prove the size
of the cephalopod it belonged to, Fastovsky told LiveScience. He found
the rest of McMenamin's new evidence similarly unconvincing.
The measurement McMenamin used to dismiss the notion of currents moving
the bones was "absolutely inapproprriate for the question he is
addressing," Fastovsky said. The analysis measures the probability of a
point in a circle falling in a certain pie-slice of that circle, he
said, not the relative stability of vertebrae in currents. In fact,
Fastovsky said, little is known about the currents of the time, and no
one has ever measured what it would take to shuffle vertebral fragments
around.
Fastovsky also pushed back against the modern analogues for the
hypothetical Kraken's behavior. Octopus middens aren't organized in nice
rows, he said. They're piles of debris. And sperm whales attack squid,
not the other way around.
There's a simpler explaination, Fastovsky said. 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?" Fastovsky said. "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, Fastovsky said.
"A perfectly reasonable, pedestrian, coherant story emerges that doesn't
require wholesale invention of what is unknown or unprecendented," he
said.
McMenamin says he hopes for more debate on his findings. So far, he said, the response to his talk has been positive.
"We're getting a message from the past," he said, "So I'm hoping the discussion is better this time."
