|Name Meaning||Tearing/biter lizard||Height||N/A|
|Pronunciation||Dack-oh-sore-us||Length||4 to 5 meters (13 to 16.4 feet)|
|Era||Mesozoic – Late Jurassic – Late Cretaceous||Weight||200 to 275 kgs (441 to 606 lbs)|
|Classification||Reptilia, Pseudosuchia, & Crocodylomorpha||Location||Europe and South America|
Imagine a crocodylomorph that, at first glance, looks a bit like a crocodile but, on second thought, looks more like a fish, especially with its shark-like tail fluke and flippers!
The snout does resemble a crocodilian snout, though, but it’s shorter and taller.
If you could envision such a creature, we congratulate you – you’ve met the unique Dakosaurus, a crocodylomorph with serrated teeth that was probably a fully pelagic reptile.
That’s quite a remarkable combination of physical traits, isn’t it?
If you’re curious to discover more, keep reading! You’re about to learn some incredible facts about the tearing lizard!
Although Dakosaurus was a crocodylomorph, its overall appearance is more similar to that of a fish than a crocodile.
However, Dakosaurus and modern crocodiles still have something in common.
More precisely, they both have large skulls and elongated bodies.
However, Dakosaurus snouts are short and high, their teeth are serrated, and their body shape is slightly different than that of a crocodile.
These characteristics make the Dakosaurus unique among other marine reptiles, as most are known to have had long snouts and sharp teeth used to catch fish.
Another thing that sets the Dakosaurus and the modern crocodile apart is the fact that the limbs of the Dakosaurus became flippers that allowed fast swimming.
Besides this, it had a tall dorsal fin and a fluke tail, both of which ensured propulsion through the water.
Additionally, while crocodiles have armored skin with thick, rugged scales, Dakosaurus skin was smooth and scaleless.
As for size, the Dakosaurus has been estimated to reach lengths of 4-5 meters (13-16.4 feet) and weights of 200-275 kilograms (441-606 pounds).
If we compare it to other members of the same tribe, the Geosaurini, we can notice that it was not the only Late Jurassic marine crocodile of such proportions.
The Torvoneustes had a similar size, measuring 4-4.7 meters (13-15.4 feet) long and weighing 275 kilograms (606 pounds).
On the other hand, it had a longer snout and smaller teeth.
The Tyrannoneustes measured roughly the same as its relatives – 4.65-5.04 meters (15.3-16.5 feet) in length.
The Geosaurus, however, was the smallest, reaching only 2.5–3 meters (8.2-9.8 feet) long and weighing 80 kilograms (176 pounds).
Habitat and Distribution
Dakosaurus fossils were discovered in multiple locations in Western Europe:
- Schnaitheim, Germany (and other locations)
- Vaca Muerta Formation, Argentina
- Possibly Mexico
The fossils discovered in Europe belong to Late Jurassic deposits, while those unearthed from Argentina’s Vaca Muerta Formation are thought to have been deposited from the Late Jurassic to Early Cretaceous.
During the Late Jurassic, Europe was part of the newly formed supercontinent called Laurasia, which appeared after Pangaea broke up and Laurasia and Gondwana became separated by the Tethys Sea.
As such, with the breakup of Pangaea, the sea levels started rising in Europe, transforming the territory into an archipelago of islands located at the edge of the Tethys Sea.
Europe and Eastern Russia had been flooded, thus connecting the Tethys Sea to the Atlantic and allowing new fauna to reach Europe.
By the end of the period, however, the shallow seaway retreated, the polar ice caps grew, and global temperatures dropped.
Europe was then dominated by cycads, conifers, ginkgos, and ferns.
The Dakosaurus living in Argentina likely inhabited a different environment.
At the time of deposition, the Argentinian formation was located on the eastern shore of the Pacific Ocean.
Behavior and Diet
Modern crocodiles are semi-aquatic reptiles that live in freshwater habitats like wetlands, lakes, and rivers. Only some gather in brackish water or saltwater.
The Dakosaurus, on the other hand, probably had a fully aquatic lifestyle and was swimming through our world’s prehistoric seas.
Scientists argue that the Dakosaurus could not move on land at all, so it spent all its life under the water.
Thanks to its four flipper-like limbs and shark-like tail fluke, the Dakosaurus was an excellent swimmer.
Another thing that sets crocodiles and Dakosaurus crocodylomorphs apart is the structure of their teeth and the prey they took.
While crocodile teeth are sharp and specialize in piercing and holding onto prey, they are unsuitable for capturing large prey.
The Dakosaurus, on the other hand, had lateromedially compressed, serrated teeth that allowed it to take large prey and twist feed.
This means that the Dakosaurus relied on tearing bits of flesh off the prey instead of piercing and holding onto it.
As such, the Dakosaurus may have fed on other large sea reptiles and creatures and may have even been an apex predator in its habitat.
Studies on the cranial osteology and feeding ecology of the Dakosaurus show it may have been a generalist feeder and possibly a suction feeder.
If it were a suction feeder, the Dakosaurus ingested prey by rapidly expanding the mouth and generating a flow of water.
It is well known that many fish rely on suction feeding as their primary method of capturing prey.
Was it indeed how the Dakosaurus fed? And if it were, what does it say about its taxonomic classification and evolution? Unfortunately, this is yet to be discovered.
The Dakosaurus may have possessed highly developed salt glands that were responsible for excreting excess salts.
Although no paleontological evidence fully confirms this, Geosaurus and Metriorhynchus are known to have possessed them, which is why scientists suspect Dakosaurus was no exception.
Most reptiles are known to reproduce sexually by laying eggs. But is this valid for fully aquatic reptiles like the Dakosaurus? Laying eggs would mean that they had to get out of the water.
Considering its flipper-like limbs and the shark-like tail fluke, it’s highly unlikely that Dakosaurus or other members of the Metriorhynchidae family could walk on land. So how did they reproduce?
Scientists think the Dakosaurus may have evolved to be viviparous, meaning it gave birth to live young. This behavior is widely studied in ichthyosaurs.
Another marine reptile scientists turn to while discussing the reproductive behavior of metriorhynchids is the Keichousaurus, a sauropterygian, which may have been ovoviviparous, which means that the eggs formed within the uterus and remained there until ready to hatch. This theory is further supported by pelvic characteristics.
However, if metriorhynchids were ovoviviparous, this would still imply that they had to reach land to lay the eggs, which is why scientists rule out the possibility of ovoviviparity, as well as oviparity.
Additionally, postcranial morphology doesn’t support ovoviviparity or oviparity as well, which is why viviparous behavior is more plausible.
Apparently, paleontologists discovered a pregnant Dakosaurus female that bore a baby with small paddle-like limbs similar to those of adults.
This serves as another piece of evidence that metriorhynchids gave live birth.
The fact that no Dakosaurus nesting sites have been discovered further supports this theory.
Metriorhynchids are also known to possess an unusually tall hip opening, suggesting they gave live birth.
Apart from this, very little else is known about Dakosaurus reproductive behavior and life cycle.
How long was the gestation period? How fast did the babies grow? Did the parents exhibit parental care?
The answers remain unknown, but we do hope that future findings and studies will reveal more jaw-dropping details!
Evolution and History
Dakosaurus is a metriorhynchid thalattosuchian.
Thalattosuchians probably originate from the Early Jurassic. More precisely, the oldest known remains date to the Sinemurian stage and were discovered in Chile and France.
On the other hand, since these remains are highly fragmented and not fully confirmed, the official earliest members of the Talattosuchia suborder are now considered Turnersuchus reptiles, which date to the Pliensbachian stage of the Early Jurassic.
The Turnersuchus already had somewhat elongated jaws, but its successors’ jaws were undoubtedly more elongated.
Some of its characteristics are now considered ancestral traits of the Teleosauroidea and Metriorhynchoidea groups.
Apart from these details, the evolution of metriorhynchid crocodylians remains poorly known because of the lack of in-depth studies, a poor understanding of their taxonomy, and the lack of basal specimens and complete skeletons.
It has been confirmed, however, that the evolution of Metriorhynchidae follows a route of highly diverse reptiles in terms of form, biodiversity, and function.
This diversification likely peaked before the Jurassic-Cretaceous boundary.
As such, since we cannot provide any more substantial details about the evolution of Dakosaurus and other metriorhynchids, why don’t we turn to the genus’ history of discovery?
It takes us back to the 19th century when the first Dakosaurus fossils were unearthed in Germany.
At first, the discovered teeth were thought to have belonged to Megalosaurus, a theropod dinosaur. Then, the species was named Geosaurus maximum.
Only years later were the fossils attributed to a new genus called Dakosaurus.
In 1871, other Dakosaurus fossils were wrongly attributed to Megalosaurus after the Austrian paleontologist Emanuel Bunzel named them Megalosaurus schnaitheimi.
Today, these fossils are thought to have belonged to a Dakosaurus maximum specimen.
The second species of the genus, Dakosaurus andiniensis, was discovered a century later in the Vaca Muerta Formation, Argentina.
Two skulls belonging to this species revealed that the Dakosaurus differed from other metriorhynchids by the shape of its snout, which was rather short and tall than elongated.
Interactions with Other Species
The aquatic creatures that competed for food with or fell prey to the ferocious Dakosaurus depend on which sea we’re discussing.
Naturally, the European paleofauna differed from the South American paleofauna.
In Europe, for example, the Dakosaurus likely shared its habitat with other similar predators, one of which was Geosaurus giganteus.
Other crocodyliforms included Cricosaurus suevicus and Rhacheosaurus gracilis. If they were all predators, how did they survive?
Scientists argue that the solution was niche partitioning, which means that these predators evolved to use their environment in ways that allowed them to coexist and avoid the extinction of competing species.
For example, Cricosaurus suevicus and Rhacheosaurus gracilis had elongated snouts and likely fed on fish.
The latter probably preyed on smaller fish, while the former may have been a generalist feeder.
In turn, Steneosaurus, another crocodyliform living in the same habitat, may have been a slow swimmer, so it relied on ambushing prey.
The same niche partitioning is valid for the two top predators.
This can be illustrated by the form of their teeth, which indicate that they relied on different capturing techniques and likely on different prey.
As such, the Dakosaurus had large, serrated teeth, while the Geosaurus had blade-like teeth.
As for the specific prey they went for, this remains unknown, but there probably was plenty, as the European shallow seas were abundant in fish and other marine creatures.
Fossil evidence shows that the Vaca Muerta Formation also revealed the remains of Cricosaurus and Geosaurus, indicating that niche partitioning occurred in South America as well.
A metriorhynchid found only in Argentina is Purranisaurus, but its ecological niche remains poorly studied.
Argentinian waters were likely abundant in ichthyosaurs, pterosaurs, and reptiles.
No wonder the Dakosaurus is often portrayed as pursuing an ichthyosaur called Caypullisaurus! Who knows? Maybe it did prey on this 7-meter (23 feet) ichthyosaur!
Without a doubt, the Dakosaurus is a unique prehistoric creature – crocodilian-like body, shark-like tail, scaleless skin, flippers instead of limbs, and unusually short and tall snout.
How can one not be fascinated by its appearance and lifestyle?
It’s no wonder the genus was the subject of numerous scientific papers aimed at outlining the possible behavior and evolution of these marine reptiles.
On the other hand, the Dakosaurus is probably less renowned in the media, as it is only featured in Jurassic Park Builder and Jurassic World: The Game.
We hope that future books, movies, or games will focus on the Dakosaurus as a main character, as we cannot deny its uniqueness! It would be a pity to leave it in the dark!
The Dakosaurus was a crocodylomorph living in Europe and South America.
It existed for approximately 20 million years, from the Late Jurassic until the Early Cretaceous.
Despite being a crocodylomorph, the Dakosaurus shared few characteristics with modern crocodiles.
Although at first glance the body appears crocodile-like, the snout was much shorter and taller, the limbs were, in fact, flippers, and the tail was shark-like.
Additionally, unlike modern crocodiles, the Dakosaurus had a scaleless body and was probably a fully pelagic reptile.
Is Dakosaurus a Mosasaur?
The Dakosaurus is not a mosasaur, as the latter is part of the Squamata order, which includes snakes and lizards.
The Dakosaurus, on the other hand, is part of the Pseudosuchia group, which includes living crocodilians and archosaurs closely related to crocodilians.