Crocodiles are the least changed of all the reptiles alive today compared to their prehistoric descendants who lived over 65 million years ago in the late Cretaceous period—although the even earlier crocodiles of the Triassic and Jurassic periods exhibited some distinctly un-crocodile-like characteristics, such as bipedal postures and vegetarian diets. Crocodiles are the least changed of all the reptiles alive today compared to their pre
The archosaurs were the “ruling lizards” of the early to middle Triassic period, and crocodiles were one of the many offspring of these “ruling lizards.” It goes without saying that the earliest dinosaurs and the earliest crocodiles looked a lot more alike than either resembled the first pterosaurs, which were also descended from archosaurs. For the most part, the structure and musculature of the earliest crocodiles’ jaws were different from those of theropod dinosaurs, making them far more lethal. They also had more spread limbs, as opposed to the straight and “locked-in” legs of theropod dinosaurs. It wasn’t until the Mesozoic Era that crocodiles developed the three key characteristics that we identify with them today: stubby legs, sleek, armored bodies, and a preference for aquatic environments.
The Triassic Period saw the appearance of the first crocodiles
Before the first true crocodiles appeared on the prehistoric landscape, there were the phytosaurs (plant lizards), which were archosaurs that looked very similar to crocodiles, except that their nostrils were located on the tops of their heads rather than the tips of their snouts. The phytosaurs (plant lizards) were archosaurs that looked very similar to crocodiles, except that their nostrils Although you may assume from their name that phytosaurs were vegetarians, these reptiles really subsisted on fish and other marine animals found in freshwater lakes and rivers all over the planet. Rutiodon and Mystriosuchus were two of the most notable phytosaurs ever discovered.
Except for the distinctive position of their noses, phytosaurs were more similar to current crocodiles than they were to the earliest real crocodiles, which was a surprising discovery. Historically, the first crocodiles were little, two-legged sprinters who lived on land, and some of them were vegetarians as well (presumably because their dinosaur cousins were better adapted to hunting for live prey). Even though the precise evolutionary connections of these early archosaurs are still disputed, Erpetosuchus and Doswellia are two of the most likely contenders for the title of “first crocodile.” Another possibility is the reclassified Xilousuchus, which lived during the early Triassic period in Asia and was a sailing archosaur with some distinguishing crocodilian features.
The truth remains that the facts on the ground throughout the middle to late Triassic era were very perplexing, regardless of the interpretation. In the area of the supercontinent, Pangea that corresponded to modern-day South America, dinosaur-like crocodiles, dinosaur-like crocodiles, and (probably) early pterosaurs that looked like both crocodiles and dinosaurs coexisted peacefully alongside one another. That it took dinosaurs to develop in a separate manner from their crocodile relatives and gradually establish their universal supremacy did not occur until the beginning of the Jurassic era. If you were transported back in time 220 million years and devoured whole, it’s unlikely that you’d be able to identify your adversary as a crocodile or a dinosaur.
Approximately 200 million years ago, at the beginning of the Jurassic era, crocodiles had mostly abandoned their terrestrial existence, most likely in reaction to the terrestrial domination attained by dinosaurs. At this point, we begin to witness the aquatic adaptations that are characteristic of contemporary crocodiles and alligators, such as lengthy bodies, splayed limbs, and snouts that are narrow, flat, and tooth-studded, with strong jaws (a necessary innovation, since crocodiles feasted on dinosaurs and other animals that ventured too close to the water). However, there was still potential for experimentation and creativity. In the case of Stomatosuchus, paleontologists assume that it subsisted on plankton and krill, similar to the way a contemporary gray whale does.
When the Cretaceous era began around 100 million years ago, certain South American crocodiles began to emulate their dinosaur relatives by growing to tremendous proportions. This occurred around the middle of that period. Known as “SuperCroc,” the massive Sarcosuchus was the king of the Cretaceous crocodiles. It spanned over 40 feet in length from head to tail and weighed in the vicinity of 10 tons, earning it the nickname “SuperCroc.” And don’t forget about the somewhat smaller Deinosuchus, whose name contains the word “deino,” which refers to the same notion as the word “dino” in the context of dinosaurs: “terrible” or “fearsome.” In addition to huge crocodiles, these giant snakes and turtles likely provided food for the giant crocodiles, with the whole South American ecology presenting an eerie similarity to Skull Island from the film “King Kong.”
When compared to their terrestrial siblings, ancient crocodiles were actually more amazing since they were able to survive the K-T extinction event, which exterminated the dinosaurs 65 million years ago and left just the crocodiles to live. What caused this is still a mystery, however, it may provide an essential insight as to why no plus-sized crocodiles were able to survive the meteor hit. Crocodiles today are very similar to their ancient counterparts, providing compelling evidence that these reptiles were, and continue to be, extraordinarily well suited to their environments.
