Jurassic Animals

[Audio] Jurassic Animals. Jurassic Animals. By: Prasanna.k.

[Audio] Jurassic Animals: Index Jurassic Animals: Introduction Jurassic Ocean Animals Jurassic Ocean Reptiles Ichthyosaurs Plesiosaurs Fish Jassuric Land Animals Land Reptiles Amphibians Pterosaurs Arthropods Mammals.

[Audio] Jurassic Animals: Introduction The Jurassic Period was the second period of the Mesozoic Era. It began around 201.3 million years ago ( Mya) and ended 145 Mya. The period before the Jurassic Period was the Triassic Period. After the Jurassic Period came the Cretaceous Period. The Jurassic Period lasted around 56 million years. Although dinosaurs first appeared during the Triassic Period, they weren't the dominant land animals during that time. That position was held by another reptilian group, the pseudosuchians..

[Audio] Jurassic Ocean Animals Although dinosaurs came to dominate on land, they never adapted to live in the ocean. Here, other groups of reptiles ruled, the best-known of which were the ichthyosaurs and the plesiosaurs..

[Audio] Jurassic Ocean Reptiles Jurassic Ichthyosaurs The word ' ichthyosaur' is derived from Greek and means ' fish lizard'. Ichthyosaurs didn't evolve directly from fish; like today's whales and dolphins, they are the descendants of land animals that adapted to life in the sea. (Ichthyosaurs are descended from land reptiles, whereas today's whales and dolphins are descended from land mammals.) Ichthyosaurs first appeared in the Triassic Period and became extinct during the Late Cretaceous..

[Audio] Ichthyosaurus Ichthyosaurus was an ichthyosaur that lived in the Early Jurassic. It is the best-known ichthyosaur and gives the group its name. Specimens have been found in Belgium, England, Germany and Switzerland. Ichthyosaurus was between 2m and 3.3m ( 6.5 and 11 ft.) in length. Its body is remarkably similar to that of today's dolphins and porpoises – animals that appeared millions of years after the Ichthyosaurus became extinct. The phenomenon of unrelated animals evolving similar physical characteristics is known as ' convergent evolution'..

[Audio] Ophthalmosaurus Like ichthyosaurus, ophthalmosaurus was a streamlined, dolphin-shaped ichthyosaur. Reaching lengths of around 6 m ( 19.5 ft.), it was significantly larger than ichthyosaurus. Ophthalmosaurus is known for its huge eyes, which were around 10 cm ( 4 in.) in diameter. The size of this Jurassic animal's eyes suggest that it was a nocturnal or deep-sea hunter. With toothless jaws, it is likely that ophthalmosaurus preyed on soft-bodied animals such as squid. Ophthalmosaurus was present during the Late Jurassic. It has been found in Europe and in the Americas..

[Audio] Jurassic Plesiosaurs In the Jurassic oceans, two groups of swimming reptiles were particularly abundant: the ichthyosaurs and the plesiosaurs. Like ichthyosaurs, plesiosaurs were descended from land reptiles. Whereas ichthyosaurs propelled themselves through the water with a large tail fin, the plesiosaurs swam using strokes of their four powerful flippers. Over the course of the Jurassic Period, the plesiosaurs split into two main branches: those with long necks and small heads, and those with short necks and large heads..

[Audio] Plesiosaurus was a typical long-necked plesiosaur. It lived during the Early Jurassic and its remains have been found in southern England. This fish and squid-eating marine reptile grew to lengths of between 3.5 and 5 m ( 11.5 and 16.5 ft.). Almost half of the animal's total length was taken up by its long neck..

[Audio] Liopleurodon Liopleurodon was a member of a group of short-necked plesiosaurs known as pliosaurs. This fearsome Jurassic animal was likely to have been an apex predator, feeding on fish, cephalopods, and a variety of marine reptiles. It may have even been able to catch unwary dinosaurs who had strayed too close to the water's edge. Liopleurodon was once thought to have grown to lengths of up to 25 m ( 82 ft.). Recent estimations have brought its maximum length down to around 6.4 m ( 21 ft.); making it slightly smaller than today's killer whales..

[Audio] Jurassic Fish Fish had been swimming in the world's oceans hundreds of millions of years prior to the start of the Jurassic Period (they are, after all, the ancestors of all vertebrates). During the Jurassic Period fish continued to evolve, and, along with the reptiles, were the primary marine vertebrates..

[Audio] Leedsichthys Reaching an estimated length of 22m ( 72 ft.) (perhaps even longer), Leedsichthys may have been the largest fish ever to have lived. Despite its large size, Leedsichthys was not a shark; instead it was a member of the fish group Osteichthyes, otherwise known as the ' bony fish'. The majority of today's fish belong to this group. Leedsichthys lived during the late Jurassic. Its remains have been found in Europe and in South America..

[Audio] Spathobatis The skeletons of cartilaginous fishes such as sharks and rays are made of cartilage, a material that is more flexible than bone. The cartilaginous fishes form one of the two main fish groups, the other being the bony fish, whose skeletons, as the name suggests, are made of bone. The two groups had split long before the start of the Jurassic Period. Spathobatis had a flat, wide body. Although it is the earliest ray yet discovered, it is thought that other rays had appeared previously, during the Early Triassic..

[Audio] Lepidotes Lepidotes is a bony fish that appeared in the Early Jurassic and which became extinct in the Late Cretaceous. It is the first-known fish to be able to extend its jaws to form a tube for sucking food into its mouth ( many of today's fish species are able to do this). Lepidotes was equipped with rows of peg-like teeth with which it crushed shellfish. In medieval times fossilized specimens of the fish's teeth were thought to be a cure for poison. The fossilized teeth – which resembled smooth round buttons – were believed to come from the heads of toads, and were called toadstones..

[Audio] Jassuric Land Animals Land Reptiles Amphibians Pterosaurs PART II WILL BE COMING SOON…… Arthropods Mammals.