Fossil reveals evidence of 200-million-year-old squid attack

Scientists have discovered the world’s oldest known example of a squid-like creature attacking its prey, in a fossil dating back almost 200 million years

The fossil was found on the Jurassic Coast of South West England in the 19th century and then mostly forgotten about. It is currently housed within the collections of the British Geological Survey in Nottingham.

In new analysis, researchers say it appears to show a squid-like creature (identified as Clarkeiteuthis montefiorei) with a herring-like fish (Dorsetichthys bechei) in its jaws.

They say the position of the arms, alongside the body of the fish, suggests this is not a fortuitous quirk of fossilisation but that it is recording an actual palaeobiological event.

They also believe it dates from between 190 and 199 million years ago, which would predate any previously recorded similar sample by more than 10 million years.

This is a most unusual if not extraordinary fossil as predation events are only very occasionally found in the geological record. It points to a particularly violent attack which ultimately appears to have caused the death, and subsequent preservation, of both animals

Professor Malcolm Hart, Emeritus Professor in Plymouth and the study’s lead author

The research was led by the University of Plymouth, in conjunction with the University of Kansas and Dorset-based company, The Forge Fossils.

In their analysis, the researchers say the fossilised remains indicate a brutal incident in which the head bones of the fish were apparently crushed by its attacker.

This suggests two possible scenarios, either the fish was too large for its attacker or became stuck in its jaws so that the pair died and sank to the seafloor.

Alternatively, the Clarkeiteuthis took its prey to the seafloor in a display of ‘distraction sinking’ to avoid the possibility of being attacked by another predator. However, in doing so it entered waters low in oxygen and suffocated.

10 facts about squid…

Squid, cuttlefish and octopus are all Cephalopods, a tiny group of highly advanced and organised, exclusively marine animals that evolved from the same mollusc ancestor. However, they are very different…

1. Squids are a different species to cuttlefish

While both may have evolved from the same mollusc ancestor, squids are different in that they all have internal bone-like structures called a pen. They look so similar that without cutting them open, even experts have difficulty telling the two apart.

2. Squids are a different species to octopus

Octopus belong to a different order of animal called octopoda. Octopi usually have rounder, squishy heads which wobble as they move whereas squid heads tend to be firmer and elongated. Octopi only have eight arms, while squid have eight arms and two tentacles. Finally, octopi prefer to stick to the sea floor and live in dens for protection, while squids prefer to live in the open.

3. Squid tentacles are very versatile

Although squids have eight arms that grow back if cut, their two tentacles do not. Their tentacles are the appendages that contain suckers along the edge, which can grip things. These allow them to either capture prey or climb up vertical surfaces when out of the water. For males, the lower half of their left tentacle lacks suckers because that end acts as their penis. The males of some species lack dedicated sex organs, using their arms to do double duty.

4. Squids have beaks

All squid species have beaks, which are sharp and pointed. These are very hard, and are used to kill and tear their prey apart. Unlike the teeth and jaws of most other animals, these beaks are made from chitin and contain no minerals whatsoever, and can even survive digestive juices. This is why squid beaks are often found inside whale stomachs when they’re opened up. Squid beaks are extremely hard to scratch or break, making them tougher and more resilient that virtually all metals and polymers.

5. Squids come in many shapes and sizes

Most squid species grow to about 24 inches long, though a number are far smaller. In the deep seas and oceans, giant squid can grow up to 43 feet long; the biggest ever found was 46 feet in length. Marine biologists suggest that they can grow bigger still, and that the only limits to their size is the available food supply.

6. Deep water squid have glow-in-the-dark organs

Deep water squid live in perpetual darkness because sunlight cannot reach the bottom of the ocean, so some species have bioluminescent organs to help them hunt for food and find their way around. This means that you can see through their skin into their organs inside, which produce their own light.

7. Squids have three hearts

This is because their bodies are very complex. Their two smaller hearts serve their gills, while the larger one pumps blood to the rest of their bodies, and all three are faintly greenish in colour. These hearts are also surrounded by their renal sacks, which is a fancy way of saying that their hearts are actually located inside their excretory organs. This layout ensures that their hearts receive extra protection.

8. Squids have the largest eyes of any animal

Compared to the size of its body, a squid’s eyes in general are very big. Giant squid, on the other hand, have the biggest eyes of any known animal in the world, even bigger than ostrich eyes. A typical giant squid eye measures some 10.62 inches across, which is roughly the size of a soccer ball. Since giant squid live only in the deep ocean where there’s no light, these eyes also come with their own light organs, meaning they literally glow in the dark.

9. Squid eyes have built-in contact lenses

Perhaps the most unusual thing about their eyes is that they change focus with their lenses. Squid eyes are protected by hard lenses, very much like the contact lenses worn by some people. If you remove these lenses, you can actually use them as magnifying glasses. When human eyes focus, we change the shape of our lenses, expanding and contracting our pupils. But when squid eyes focus, they change the position of their lenses in the same way that cameras and telescopes do.

10. One squid can shoot light

Squid and octopus can shoot black ink at predators in order to get away, but the heteroteuthis dispar does it differently. Instead of ink, they produce bioluminescent mucous in their ink sacks. When threatened, they shoot out this light-producing snot, which blinds or confuses their predators. The result is a cloud of light that takes a while to dissipate, which is why this species is also called the fire shooter.

Summary

There are 304 known species of squid, but they are so diverse that we discover new ones all the time. They range from just a few inches long to as big as several feet, but can reach over 40 feet in length. While most squirt ink as a form of self-defence, others use light, and still others make themselves invisible through camouflage. It’s hard to tell them apart from cuttlefish, but you can tell squids apart from octopi because they have eight arms and two tentacles, while octopi have only eight arms.

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