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A = Anapsid, B = Synapsid, C = Diapsid. It was traditionally assumed that first reptiles were anapsids, having a solid skull with holes only for the nose, eyes, spinal cord, etc.; [10] the discoveries of synapsid-like openings in the skull roof of the skulls of several members of Parareptilia, including lanthanosuchoids, millerettids, bolosaurids, some nycteroleterids, some procolophonoids and ...
• Sea snake (bottom right) Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. Only about 100 of the 12,000 extant reptile species and subspecies are classed as marine reptiles, including marine iguanas, sea snakes, sea turtles and saltwater crocodiles. [1]
Fossils readily identifiable as snakes (though often retaining hind limbs) first appear in the fossil record during the Cretaceous period. [24] The earliest known true snake fossils (members of the crown group Serpentes) come from the marine simoliophiids , the oldest of which is the Late Cretaceous ( Cenomanian age) Haasiophis terrasanctus ...
The first ray-finned and lobe-finned bony fish appeared in the Devonian, while the placoderms began dominating almost every known aquatic environment. However, another subclass of Osteichthyes, the Sarcopterygii ( which includes lobe-finned fish like coelacanths and lungfish , as well as and tetrapods ), was the most diverse group of bony fish ...
The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. [1] Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.
Ichthyosaurian species varied from 1 to 26 metres (3 to 85 ft) in length. Ichthyosaurians resembled both modern fish and dolphins. Their limbs had been fully transformed into flippers, which sometimes contained a very large number of digits and phalanges. At least some species possessed a dorsal fin. Their heads were pointed, and the jaws often ...
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Distraction eye, many fish have spot on the tail to fool potential predators and prey; both are not sure which is the front, the direction of travel. [133] Gills appear in unrelated fish, some amphibians, some crustacean, aquatic insects and some mollusk, like freshwater snails, squid, octopus. [134]