Lepidosaurs . They are a superorder of diapsid sauropsids with overlapping scales. They include tuátaras , lizards , snakes, and amphibians . Lepidosaurs are the current reptiles with the greatest evolutionary success.
Classification
- Squamous Lepidosaurs: The Squamous are an order of reptiles (superorder for some authors) that groups the suborders Ofidios (snakes and snakes) and Saurios (lizards). The name is indicative of the characteristic of the body, covered with small scales. This is the group that comprises the majority of living reptiles (about 95%).
- Saurios: They are known as lizards. These are generally long-tailed reptiles, mouth without dilation capacity, shoulder girdle, four well-developed legs that, although adapted to locomotion, do not prevent the abdomen and tail from dragging during movement. The scales that they have on the head and sometimes on other parts of the body, have their own name and give them a systematic character to determine the species. The eyelids are free (mobile).
- Ophidians: with those known as snakes and snakes. These are reptiles lacking fore and hind limbs, for this reason they crawl (in some genera there are very rudimentary forelimbs). They present an elongated trunk and tail, with a head that may be more or less differentiated from the neck. The body is lined with a thick horny layer divided into elements (can have up to 500 vertebrae, each with a pair of ribs). The ribs are very curved and have no sternum. They do not have mobile eyelids, but there is a fixed and transparent one covering the entire eyeball. The tongue is long, thin and forked. According to the distribution and shape of the teeth, ophidians are classified Aglifos, when they have solid teeth; Opistoglyphs, if they have corrugated teeth;
- Rincocephalic Lepidosaurs: they are reptiles with origins in the Mesozoic, currently represented by a single living species, the tuátara. They are characterized by presenting a long beak-shaped head. The aforementioned tutata (Sphaenodon punctatus) is a true living fossil, it has the shape of a lizard of large dimensions, a large head, well-developed eyes, and a dorsal ridge formed by thorny tubercles, which extends from the occiput to the tail. It inhabits the islands of New Zealand.
The evolution of lepidosaurs
The evolution of lepidosaurs Lizards, snakes and sphenodonts make up the group of lepidosaurs, whose origin goes back beyond the dinosaurs. The evolution of lepidosaurs in the northern hemisphere had a different course from that followed in the southern Sebastián Apesteguía as birds are among the type of diapsid reptiles, whose Before dinosaurs were dinosaurs. And the dinosaurs among the reptiles. Considered as a whole, reptiles are the group that contributes the greatest diversity to terrestrial vertebrates. There are some 15,400 living species and numerous skulls have two bone bars and two windows on each side for the passage of the chewing muscles. The history of lepidosaurs can be traced back to the beginning of the Triassic, about 250 million years ago, When living beings took over terrestrial ecosystems, lepidosaurs were already populating the ancient Pangea supercontinent, where the diversity of their species and the breadth of their adaptations and anatomical features increased. The lineage of the most fossil lepidosaurs. They were fighting to recover from one of the comes from Paleozoic precursors. Among the living reptiles, they are the most terrible extinction episodes, among which there were running forms, one of the groups plus the one from the Permian transition to the one like Paliguana and Saurosternon, and spacious. Due to their anatomy they belong Triassic. gliders, like Kuehneosaurus and Icarosaurus. However, the main milestones in the history of Lepidosaurs took place after the permo-Triassic extinction,
