Fossil Icthyosaur Vertebra from the Jurassic Coast, Dorset, UK
This piece is not for sale.
AGE: 160 million/Kimmeridge Clay
SPECIES: Unknown, possibly Icthyosaurus SIZE: Approx 3.4'. across x 1.1". deep LOCATION: Portland, Dorest, UK
This is a self-collected specimen from Portland, UK, found on New Year's Day of 2019.
Ichthyosaursare large extinctmarine reptiles. Ichthyosaurs belong to the order known asIchthyosauria orIchthyopterygia ('fish flippers' – a designation introduced by SirRichard Owenin 1840, although the term is now used more for the parentcladeof the Ichthyosauria). Ichthyosaurs lived during the time of thedinosaurs, but formed a separate group from the dinosaurs and may not have been closely related to them.
Ichthyosaurs thrived during much of theMesozoicera; based onfossilevidence, they first appeared around 250 million years ago and at least one species survived until about 90 million years ago,into theLate Cretaceous. During theearly Triassicperiod, ichthyosaurs 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-daydolphinsandwhalesreturned to the sea millions of years later, which they gradually came to resemble in a case ofconvergent evolution. Ichthyosaurs were particularly abundant in thelater Triassicandearly Jurassicperiods, until they were replaced as the top aquatic predators by another marine reptilian group, thePlesiosauria, in thelater JurassicandCretaceousperiods. In the Late Cretaceous, ichthyosaurs were hard hit by theCenomanian-Turonian anoxic event. Their last lineage became extinct for unknown reasons.
Mary Anning, the greatest fossilist ever to have lived, discovered the first complete Icthyosaur skeletons in England.
Science became aware of the existence of ichthyosaurs during the early nineteenth century, when the first complete skeletons were found in England by Mary Anning of Lyme Regis. In 1834, the order Ichthyosauria was named. Later that century, many excellently preserved ichthyosaur fossils were discovered in Germany, including soft-tissue remains. 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.
Ichthyosaur species varied from one to over sixteen metres in length. Ichthyosaurs 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 were equipped with conical teeth that could help to catch smaller prey. Some species had larger, bladed teeth with which they could attack large animals. The eyes were very large, probably useful when deep diving. The neck was short, and later species had a rather stiff trunk. These also had a more vertical tail fin, used for a powerful propulsive stroke. The vertebral column, made of simplified disc-like vertebrae, continued into the lower lobe of the tail fin. Ichthyosaurs were air-breathing, warm-blooded, and bore live young. They may have had a layer ofblubberfor insulation