In 1807, the last specimen was described by the latter's cousin, Joseph Hawker. In October 1805, a newspaper article reported the find of two additional skeletons, one discovered at Weston by Jacob Wilkinson, the other, at the same village, by Reverend Peter Hawker. In 1804, Edward Donovan at St Donats uncovered a four-metre-long (13 ft) ichthyosaur specimen containing a jaw, vertebrae, ribs, and a shoulder girdle. In the early nineteenth century, this resulted in the discovery of more complete skeletons. The demand by collectors led to more intense commercial digging activities. The bones had typically been labelled as belonging to fish, dolphins, or crocodiles the teeth had been seen as those of sea lions. Those of the naturalists Ashton Lever and John Hunter were acquired in their totality by museums later, it was established that they contained dozens of ichthyosaur bones and teeth. Towards the end of the eighteenth century, British fossil collections quickly increased in size. In 1779, ichthyosaur bones were illustrated in John Walcott's Descriptions and Figures of Petrifications. In 1783, this piece was exhibited by the Society for Promoting Natural History as those of a crocodilian. In 1766, an ichthyosaur jaw with teeth was found at Weston near Bath. In 1708, the Swiss naturalist Johann Jakob Scheuchzer described two ichthyosaur vertebrae assuming they belonged to a man drowned in the Universal Deluge. Lhuyd thought that they represented fish remains. The first known illustrations of ichthyosaur bones, vertebrae, and limb elements were published by the Welshman Edward Lhuyd in his Lithophylacii Brittannici Ichnographia of 1699. Main article: Timeline of ichthyosaur research Early finds They may have had a layer of blubber for insulation. Ichthyosaurs were air-breathing, warm-blooded, and bore live young. The vertebral column, made of simplified disc-like vertebrae, continued into the lower lobe of the tail fin. These also had a more vertical tail fin, used for a powerful propulsive stroke. The neck was short, and later species had a rather stiff trunk. The eyes were very large, for deep diving. Some species had larger, bladed teeth to attack large animals.

Their heads were pointed, and the jaws often were equipped with conical teeth to catch smaller prey. At least some species possessed a dorsal fin. Their limbs had been fully transformed into flippers, which sometimes contained a very large number of digits and phalanges. Ichthyosaurs resembled both modern fish and dolphins.

Ichthyosaur species varied from 1 to 20 metres (3 to 66 ft) in length. Since the late twentieth century, there has been a revived interest in the group, leading to an increased number of named ichthyosaurs from all continents, with over fifty valid genera being now known. Later that century, many excellently preserved ichthyosaur fossils were discovered in Germany, including soft-tissue remains. In 1834, the order Ichthyosauria was named. Science became aware of the existence of ichthyosaurs during the early nineteenth century, when the first complete skeletons were found in England. Ichthyosaurs diversity declined due to environmental volatility caused by climatic upheavals in the early Late Cretaceous, becoming extinct around the Cenomanian-Turonian boundary approximately 90 million years ago. Ichthyosaurs were particularly abundant in the Late Triassic and Early Jurassic periods, until they were replaced as the top aquatic predators by another marine reptilian group, the Plesiosauria, in the later Jurassic and Early Cretaceous, though previous views of ichthyosaur decline during this period are probably overstated. During the Early Triassic epoch, ichthyosaurs and other ichthyosauromorphs evolved from a group of unidentified land reptiles that returned to the sea, in a development similar to how the mammalian land-dwelling ancestors of modern-day dolphins and whales returned to the sea millions of years later, which they gradually came to resemble in a case of convergent evolution. Ichthyosaurs thrived during much of the Mesozoic era based on fossil evidence, they first appeared around 250 million years ago ( Ma) and at least one species survived until about 90 million years ago, into the Late Cretaceous. Ichthyosaurs belong to the order known as Ichthyosauria or Ichthyopterygia ('fish flippers' – a designation introduced by Sir Richard Owen in 1842, although the term is now used more for the parent clade of the Ichthyosauria). Ichthyosaurs (Ancient Greek for 'fish lizard' – Ancient Greek: ἰχθύς, romanized: ichthys, lit.'fish' and Ancient Greek: σαῦρος, romanized: sauros, lit.'lizard') are large extinct marine reptiles.

Prehistoric kingdom animals