write 40 notes about crocodile reptile with limbs
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Answer:
When walking on land, crocodiles hold themselves high on all four legs. The characteristic sinusoidal (side-to-side) flexure of the body is caused by the movement of a front leg in concert with the opposing hind leg during each step. A cantilevered tail also balances the body.The legs can be used for steering, pushing one way or another to help guide the body. As the crocodile speeds up, however, the legs become ineffective in this role and are simply folded back against the body to reduce drag.
Answer:
crocodile, (order Crocodylia, or Crocodilia), any of 23 species of generally large, ponderous, amphibious animals of lizard-like appearance and carnivorous habit belonging to the reptile order Crocodylia. Crocodiles have powerful jaws with many conical teeth and short legs with clawed webbed toes. They share a unique body form that allows the eyes, ears, and nostrils to be above the water surface while most of the animal is hidden below. The tail is long and massive, and the skin is thick and plated.
The crurotarsans make up one of the two major clades of archosaurs. (The members of clade Avemetatarsalia, which include dinosaurs, pterosaurs, and modern birds, make up the second group.) Crurotarsans are distinguished from other archosaurs by the arrangement of the bones in their ankles; the connection between the astragalus (the talus, or medial proximal ankle bone) and the calcaneum (the lateral proximal ankle bone) in crurotarsans is a peg-in-socket, which allows for ankle rotation. This adaptation enables the animal to display a “high walk” (which elevates the body when the animal’s legs are brought inward toward the midline of the body) and a sprawling stance (which lowers the body when the legs are spread far apart from one another). In contrast, the ankle bones in other archosaurs allow the foot to bend only one way, which limited these animals to a more-erect posture.
The crurotarsans comprise several distinct lineages. Some paleontologists argue that the phytosaurs (“plant reptiles”), also known as parasuchians, were the first lineage to evolve; they were semiaquatic and possessed extended snouts similar to those found in modern gavials. Phytosaurs were so named because petrified mud filled in the grooves and leveled the teeth of the first fossil specimen. Since flattened teeth are indicative of a lifestyle that relies on crushing and grinding plant material, phytosaurs were thought to be herbivorous until researchers discovered and removed the petrified mud.