Grands reptiles éteints appelés ichthyosaures. Les ichtyosaures sont membres de l’Ichthyosaurie ou de l’Ichtyoptère.
Les ichtyosaures ont prospéré pendant la majeure partie de l’ère mésozoïque; Selon Fossilâ, ils ont initialement émergé il y a environ 250 millions d’années, et au moins une espèce vivait jusqu’au Crétacé supérieur, il y a environ 90 millions d’années. Les ichthyosaures ont évolué à partir d’un groupe non identifié de reptiles terrestres qui sont revenus à la mer au début de l’époque du trias est graduellement venu à res
Résolution: 601 × 460
Tamanho: 123 KB
Format d'image: .png
Télécharger dd>
Résolution: 1229 × 438
Tamanho: 372 KB
Format d'image: .png
Télécharger dd>
Résolution: 925 × 525
Tamanho: 115 KB
Format d'image: .png
Télécharger dd>
Résolution: 1100 × 542
Tamanho: 244 KB
Format d'image: .png
Télécharger dd>
Résolution: 631 × 310
Tamanho: 36 KB
Format d'image: .png
Télécharger dd>
Résolution: 1024 × 1024
Tamanho: 329 KB
Format d'image: .png
Télécharger dd>
Résolution: 1200 × 1500
Tamanho: 746 KB
Format d'image: .png
Télécharger dd>
Résolution: 693 × 800
Tamanho: 298 KB
Format d'image: .png
Télécharger dd>
Résolution: 1157 × 530
Tamanho: 261 KB
Format d'image: .png
Télécharger dd>
Résolution: 1000 × 414
Tamanho: 213 KB
Format d'image: .png
Télécharger dd>
Résolution: 1200 × 2100
Tamanho: 1746 KB
Format d'image: .png
Télécharger dd>
Résolution: 2037 × 1488
Tamanho: 1066 KB
Format d'image: .png
Télécharger dd>
Résolution: 1044 × 527
Tamanho: 654 KB
Format d'image: .png
Télécharger dd>
Résolution: 995 × 600
Tamanho: 699 KB
Format d'image: .png
Télécharger dd>
Résolution: 953 × 953
Tamanho: 274 KB
Format d'image: .png
Télécharger dd>
Résolution: 681 × 295
Tamanho: 83 KB
Format d'image: .png
Télécharger dd>
Résolution: 600 × 600
Tamanho: 27 KB
Format d'image: .png
Télécharger dd>
Résolution: 1000 × 367
Tamanho: 382 KB
Format d'image: .png
Télécharger dd>
Résolution: 1000 × 622
Tamanho: 372 KB
Format d'image: .png
Télécharger dd>
Résolution: 1024 × 1024
Tamanho: 243 KB
Format d'image: .png
Télécharger dd>
Résolution: 512 × 512
Tamanho: 44 KB
Format d'image: .png
Télécharger dd>
Résolution: 640 × 237
Tamanho: 120 KB
Format d'image: .png
Télécharger dd>
Résolution: 2560 × 1463
Tamanho: 1352 KB
Format d'image: .png
Télécharger dd>
Résolution: 1000 × 690
Tamanho: 596 KB
Format d'image: .png
Télécharger dd>
Résolution: 800 × 693
Tamanho: 606 KB
Format d'image: .png
Télécharger dd>
Résolution: 1000 × 483
Tamanho: 529 KB
Format d'image: .png
Télécharger dd>
Résolution: 1183 × 557
Tamanho: 585 KB
Format d'image: .png
Télécharger dd>
Résolution: 860 × 600
Tamanho: 15 KB
Format d'image: .png
Télécharger dd>
Résolution: 470 × 275
Tamanho: 124 KB
Format d'image: .png
Télécharger dd>
Résolution: 597 × 236
Tamanho: 38 KB
Format d'image: .png
Télécharger dd>
Résolution: 800 × 543
Tamanho: 256 KB
Format d'image: .png
Télécharger dd>
Résolution: 801 × 250
Tamanho: 120 KB
Format d'image: .png
Télécharger dd>
Résolution: 641 × 436
Tamanho: 32 KB
Format d'image: .png
Télécharger dd>
When the first complete ichthyosaur bones were discovered in England in the early 1800s, science became aware of their existence. The order Ichthyosauria was established in 1834. Many well-preserved ichthyosaur fossils, including soft-tissue remnants, were unearthed in Germany later that century. There has been a renewed interest in the group since the late twentieth century, resulting in a rise in the number of identified ichthyosaurs from all continents, with over fifty genuine taxa being recognized.
The length of several Ichthyosaur species ranged from 1 to 16 meters (3 to 52 feet). Ichthyosaurs looked like a cross between current fish and dolphins. Their limbs had been completely converted into flippers, with a high number of digits and phalanges on occasion. A dorsal fin was present in at least some species. Their heads were pointed, and their jaws typically had conical teeth to aid in the capture of smaller prey. Larger, bladed teeth were seen in some species, allowing them to attack huge animals. The eyes were enormous, which was presumably advantageous for deep dives. The neck was short, and the trunk of later species was rigid. There was also a more vertical tail fin on them, which was employed for a forceful propelling stroke. The simple disc-like vertebrae of the vertebral column persisted into the lower lobe of the tail fin. Ichthyosaurs were warm-blooded, air-breathing creatures that gave birth to live offspring. They may have been insulated by a coating of blubber.
Edward Lhuyd of Wales provided the earliest known pictures of ichthyosaur bones, vertebrae, and limb parts in his Lithophylacii Brittannici Ichnographia in 1699. They seemed to Lhuyd to be fish remnants. Johann Jakob Scheuchzer, a Swiss biologist, published two ichthyosaur vertebrae in 1708, presuming they belonged to a man perished in the Universal Deluge. An ichthyosaur jaw with teeth was discovered near Bath in 1766. The Society for Promoting Natural History presented this item in 1783 as crocodilian skin. In John Walcottâs Descriptions and Figures of Petrifications, published in 1779, ichthyosaur bones were shown. The extent of British fossil collections significantly grew at the end of the eighteenth century. Naturalists Ashton Lever and John Hunterâs collections were purchased in their whole by museums, and it was later discovered that they contained hundreds of ichthyosaur bones and teeth. The bones were usually identified as those of fish, dolphins, or crocodiles, and the teeth as those of sea lions.
Due to the increased demand from collectors, commercial digging activities became more aggressive. This led in the finding of more complete bones in the early nineteenth century. Edward Donovan discovered a four-metre-long (13-foot) ichthyosaur specimen with a jaw, vertebrae, ribs, and a shoulder girdle in St Donats in 1804. It was thought to be a massive lizard. In October 1805, a newspaper story announced the discovery of two further bones, one by Jacob Wilkinson at Weston and the other by Reverend Peter Hawker in the same settlement. Joseph Hawker, the latterâs relative, described the final specimen in 1807. As a result, geologists dubbed this specimen âHawkerâs Crocodile.â An ichthyosaur jaw was discovered in Stratford-upon-Avon in 1810, and it was merged with plesiosaur bones to create a more complete specimen, indicating that the distinctive character of ichthyosaurs was still unknown, pending the discovery of considerably better specimens.