There were numerous kinds of marine reptiles which swam in the oceans during the Mesozoic Era, including the ichthyosaurs, plesiosaurs, and mosasaurs. Less well known are the marine crocodilians, or more accurately, crocodylomorphs. These animals are known as the thalattosuchians, or “sea crocodiles”. These were prehistoric crocodile relatives which took aquatic living to its most extreme level, with their legs turned into flippers and with lobed shark-like tails, and many species even lost their armored scutes and scales so that they would be completely smooth-skinned, like dolphins or seals. This article concerns one of the most well-known (and also rather mis-understood) species within the group – Dakosaurus.
Dakosaurus, whose name means “biter lizard”, came to the attention of the general public in November 2005 when the mainstream media announced a new discovery of a specimen in Argentina which included a fairly well-preserved skull. The media quickly dubbed this animal “Godzilla” due to its intimidating appearance and the pre-conceived idea that it was a super-predator which dominated its environment (hint: it wasn’t, and it didn’t). Since then, Dakosaurus paleo-art has been plastered all over the internet.
However, this animal has been known to the scientific community for much longer than that, since at least the middle of the 1800s. The genus Dakosaurus was officially named in 1856 by the German geologist and paleontologist Friedrich August von Quenstedt, based upon teeth. It was named Dakosaurus maximus based upon the unusually large size of these teeth, which hinted that it was an unusually large animal compared to other marine crocodylomorphs. However, when body fossils were afterwards discovered, it was shown that Dakosaurus reached approximately the same general size as most other marine crocs (around 15 feet long). However, its skull was shorter and its teeth were proportionally larger than its relatives. Later, another species was found within South America during the 1980s, and was officially named Dakosaurus andiniensis in 1996. There might be a third species from Mexico, but the remains are not diagnostic enough to tell if they belong to an already-named species or an entirely new species.
Dakosaurus maximus lived in the seas which covered Europe and possibly Mexico during the late Jurassic Period 150-147 million years ago. Its sister species Dakosaurus andiniensis (which might have evolved directly from its predecessor) lived in the sea that covered Argentina during the Jurassic/Cretaceous transition, 147-142 MYA.
Dakosaurus belonged to a group of advanced marine crocodylomorphs called the “metriorhynchids”. These animals were the most aquatically-adapted of all of the sea-going crocs, with flippered limbs, finned tails, and scale-less bodies. Genera within this group include Metriorhynchus itself, Geosaurus, Cricosaurus, Plesiosuchus, Torvoneustes, and many others. Nearly all of them had slight modifications of the same general body plan. However, Dakosaurus was different. The skull of D. maximus was short and triangular, and bore more of a resemblance to certain early theropod dinosaurs. The skull of its sister species D. andiniensis was even shorter and boxier and its dinosaur-esque head has made it a favorite subject for paleo-art. Its dinosaurian appearance led people to portray this animal as the ultimate predator within its ecosystem, like some sort of marine version of T. rex. In fact, it was nothing of the sort. The 15 foot long Dakosaurus shared its world with several marine reptiles, some of which were far bigger and more fearsome, such as the 18 foot long Plesiosuchus and the 35 foot long Pliosaurus, which would have easily gobbled little Dakosaurus down for a snack.
I chose to illustrate the earlier Jurassic species Dakosaurus maximus because there is A LOT of Dakosaurus andiniensis art out there, and I feel that its sister species has been shunted into the background. The drawing was made with black ballpoint pen, No.2 pencil, and Crayola and Prismacolor colored pencils, and augmented with some touching up on the computer.
Dakosaurus maximus. © Jason R. Abdale (September 15, 2023).
If you enjoy these drawings and articles, please click the “like” button, and leave a comment to let me know what you think. Subscribe to this blog if you wish to be immediately informed whenever a new post is published. Kindly check out my pages on Redbubble and Fine Art America if you want to purchase merch of my artwork.
Keep your pencils sharp, everyone.
Categories: Paleontology, Uncategorized
DINOSAURS AND BARBARIANS 
Beautiful work! Metriorhynchids are fascinating animals, and I love how you reconstructed the more overlooked species. 🙂 It may be fun to see a comparison between the two.