If it has a nightmarish
name, the vampire squid is not a dangerous predator.
It hides in deep, dark
water, waiting to catch crumbs of organic matter that pass by.
But since when has it been
behaving like this? An unexpected rediscovery brings new clues.
The vampire of the abyss
(Vampyroteuthis infernalis), also called vampire squid, is a small cephalopod
that lives in the ocean depths.
In spite of its relatively
frightening morphology, this animal rarely exceeds 30 centimeters in length and
does not present any danger to humans.
1. Modern vampire squid Vs old fossil
Recently, researchers have
rediscovered a 30 million year old fossil of vampire squid.
Its study should enable
scientists to understand why, today, the modern vampire squid can live at great
depths, whereas most other squid species cannot.
The modern vampire squid can thrive in deep, oxygen-poor ocean waters, unlike many other squid species that require shallower habitat along continental shelves.
However, few of the fossil
ancestors of today's vampire squid survive, so biologists are not sure when
these elusive cephalopods developed the ability to live with little oxygen.
The new analysis of the
fossils helps fill a 120 million year gap in the evolution of vampire squid;
revealing that the ancestors of modern vampire squid were already living in the
deep oceans during the Oligocene, 23 million to 34 million years ago.
These squids probably
evolved into low-oxygen waters during the Jurassic, explains Martin Košťák, a
paleontologist at Charles University in Prague.
2. A rediscovered fossil
Košťák and colleagues
found the long-lost fossil in the collections of the Hungarian Natural History
Museum in 2019, searching for fossils of cuttlefish ancestors.
The fossil was originally
discovered in 1942 by Hungarian paleontologist Miklós Kretzoi, who identified
it as a squid about 30 million years old and named it Necroteuthis hungarica.
More recent studies,
however, have argued that it was an ancestor of the cuttlefish.
In 1956, during the
Hungarian Revolution, the museum was set on fire and the fossil was reportedly
destroyed. The rediscovery was a pleasant surprise.
Košťák and his colleagues
studied the fossil by scanning electron microscopy and performed a geochemical
analysis.
They first discovered that
the initial identification of Kretzoi was correct: the fossil comes from a squid,
not a cuttlefish ancestor.
The animal's inner shell,
or gladius, which forms the backbone of its body, is about 15 centimeters long,
suggesting that the squid was about 35 cm long with the tentacles included.
This is just slightly
larger than the modern vampire squid, which reaches about 28 cm in length.
3. Animals living in the ocean depths
The sediments surrounding
the fossil show no trace of microfossils, often found on the sea floor,
suggesting that squid did not live in shallow water.
The researchers also
analyzed the levels of carbon variation in the sediment and found that the
sediment probably came from an anoxic or oxygen-poor environment.
These conditions are
characteristic of the deep ocean floor.
By observing the layers of
rock above where the fossil was deposited outside of what is now Budapest.
The researchers were also able to show that
the squid probably could not have survived in the shallower seas of the time.
The shallow sea deposits
showed very high levels of particular plankton that thrives in salt-poor and nutrient-rich
environments - conditions that modern vampire squid cannot tolerate.
Researchers at the
Monterey Bay Research Institute have discovered that when hiding in the deep
sea, these squid do not behave like the nightmarish predators their name
suggests;
Rather, they wait in their
dark habitats for crumbs of organic matter to float away.
Then they capture these
pieces with suction cups covered with mucus.
4. Vampire squid: why does it live in the abyss
New research, published in
the journal Communications Biology, shows how the ancestors of the vampire
squid learned to live where other squid couldn't.
Looking deeper into the
fossil record, the oldest fossils of this group of squid are from the Jurassic period,
between 201 million and 174 million years ago, and are generally found in anoxic
sediments.
Life in stable, low-oxygen
levels brings evolutionary advantages: low predation pressure and less
competition.
There is a gap in the
fossil record of the Lower Cretaceous, which began about 145 million years ago.
The squid may have already
moved into the deeper ocean at this stage, explains Košťák, driven by its
experiments with anoxic conditions during the Jurassic period.
This deep-sea lifestyle
could explain why squid survived the crisis that killed the non-Avian dinosaurs
at the end of the Cretaceous.
5. Summary: The rediscovery was a happy surprise.
The fossil comes from a
squid, not from an ancestor of the cuttlefish.
The inner shell of the
animal, or gladius, which forms the backbone of its body, is about 15
centimeters long, whereas the length of the squid including the arms is about
13.7 inches (35 centimeters).
This size is only slightly
larger than the modern vampire squid, which reaches an overall length of about
11 inches (28 centimeters).
The sediments surrounding the fossils show no trace of the microfossils often found on the ocean floor.
This shows that ancient squid did not live in shallow water.
The researchers also
analyzed the degree of carbon variation in the sediments and found that the
sediments probably came from an anoxic or oxygen-poor environment.
This condition is a
characteristic of the deep sea floor.
By looking at the rock layers
above where the fossils were stored outside Budapest, the researchers were also
able to show that squid might not have been able to survive in shallower seas
at that time.
The shallow marine
deposits have very high levels of certain plankton that thrive in a salt-poor
and highly nutritious environment, conditions that modern vampire squid cannot
tolerate.
Researchers at the
Monterey Bay Research Institute (MBRI) discovered that while hiding in the deep
sea, this squid did not behave as the nightmarish predator its name implies.
Instead, they wait in their dark habitat for crumbs of organic matter to fly away.
Then they caught
the pieces with a suction cup covered with mucus, found MBARI.
