Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are members of the largest crinoid order, Comatulida. Crinoids are echinoderms in the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. They live in both shallow water and in depths over 9,000 metres (30,000 ft).
Plesiosaurus is a genus of extinct, large marine sauropterygian reptile that lived during the Early Jurassic. It is known by nearly complete skeletons from the Lias of England. It is distinguishable by its small head, long and slender neck, broad turtle-like body, a short tail, and two pairs of large, elongated paddles. It lends its name to the order Plesiosauria, of which it is an early, but fairly typical member. It contains only one species, the type, Plesiosaurus dolichodeirus. Other species once assigned to this genus, including P. brachypterygius, P. guilielmiimperatoris, and P. tournemirensis have been reassigned to new genera, such as Hydrorion, Seeleyosaurus and Occitanosaurus.
Scelidosaurus is a genus of herbivorous armoured ornithischian dinosaur from the Jurassic of England.
Sarcosaurus is a genus of basal neotheropod dinosaur, roughly 3.5 metres (11 ft) long. It lived in what is now England and maybe Ireland and Scotland during the Hettangian-Sinemurian stages of the Early Jurassic, about 199-196 million years ago. Sarcosaurus is one of the earliest known Jurassic theropods, and one of only a handful of theropod genera from this time period. Along with Dracoraptor hanigani it is one of the two described neotheropods from the lowermost Jurassic of the United Kingdom.
Chondrosteus is a genus of extinct marine actinopterygian belonging to the family Chondrosteidae. It lived during the Hettangian and Sinemurian in what is now England. Chondrosteus is related to sturgeons and paddlefishes as part of the clade Acipenseriformes, and is one of the earliest known definitive members of the group. Similar to sturgeons, the jaws of Chondrosteus were free from the rest of the skull. Its scale cover was reduced to the upper lobe of the caudal fin like in paddlefish.
Dapedium is an extinct genus of primitive marine neopterygian ray-finned fish. The first-described finding was an example of D. politum, found in the Lower Lias of Lyme Regis, on the Jurassic Coast of England. Dapedium lived in the Late Triassic to the Middle Jurassic period, from the late Norian to the early Aalenian.
The Saltrio Formation is a geological formation in Italy. It dates back to the Early Sinemurian, and would have represented a pelagic or near-epicontinental environment, judging by the presence of marine fauna such as the nautiloid Cenoceras. The Fossils of the Formation were described on the late 1880s and revised on 1960s, finding first marine biota, such as Crinoids, Bivalves and other fauna related to Epicontinental basin deposits.
The Blue Lias is a geological formation in southern, eastern and western England and parts of South Wales, part of the Lias Group. The Blue Lias consists of a sequence of limestone and shale layers, laid down in latest Triassic and early Jurassic times, between 195 and 200 million years ago. The Blue Lias is famous for its fossils, especially ammonites.
Encrinus is an extinct genus of crinoids, and "one of the most famous". It lived during the Late Silurian-Late Triassic, and its fossils have been found in Europe.
Comatulida is an order of crinoids. Members of this order are known as feather stars and mostly do not have a stalk as adults. The oral surface with the mouth is facing upwards and is surrounded by five, often divided rays with feathery pinnules. Comatulids live on the seabed and on reefs in tropical and temperate waters.
Anningasaura is an extinct genus of basal plesiosaur. It is known from a single type species, A. lymense, discovered in Early Jurassic rocks of Lyme Regis in the United Kingdom.
Metacrinus rotundus, the Japanese sea lily, is a species of stalked crinoid in the family Isselicrinidae. It is a species found off the west coast of Japan, near the edge of the continental shelf at a depth of around 100 to 150 metres deep. This is the shallowest-living species among the extant stalked crinoids.
Agaricocrinus americanus, also known as the mushroom crinoid or American crinoid, is a species of extinct crinoid. Its fossils can be found in the U.S. states of Indiana, Tennessee and Kentucky. They date back to the Lower Mississippian, about 345 million years ago.
Bourgueticrinida is an order of crinoids that typically live deep in the ocean. Members of this order are attached to the seabed by a slender stalk and are known as sea lilies. While other groups of crinoids flourished during the Permian, bourgueticrinids along with other extant orders did not appear until the Triassic, following a mass extinction event in which nearly all crinoids died out.
Cenocrinus is a monotypic genus of stalked crinoids in the family Isselicrinidae. The great West Indian sea lily is the only species in the genus and is found in deep waters in the Caribbean Sea and Gulf of Mexico.
The Charmouth Mudstone Formation is a geological formation in England, dating to the Early Jurassic (Sinemurian–Pliensbachian). It forms part of the lower Lias Group. It is most prominently exposed at its type locality in cliff section between Lyme Regis and Charmouth but onshore it extends northwards to Market Weighton, Yorkshire, and in the subsurface of the East Midlands Shelf and Wessex Basin. The formation is notable for its fossils, including those of ammonites and marine reptiles and rare dinosaur remains. The formation played a prominent role in the history of early paleontology, with its Lyme Regis-Charmouth exposure being frequented by fossil collectors including Mary Anning.
Dracoraptor is a genus of coelophysoid dinosaur that lived during the Hettangian stage of the Early Jurassic Period of what is now Wales dated at 201.3 ± 0.2 million years old.
Delocrinus is a genus of extinct crinoids, belonging to the family Catacrinidae. Specimens have been found in Kansas, Missouri, Nebraska, Nevada, Oklahoma, Arizona, Iowa, Texas, Utah and Virginia.
The Moltrasio Formation also known as the Lombardische Kieselkalk Formation is a geological formation in Italy and Switzerland. This Formation mostly developed in the Lower or Middle Sinemurian stage of the Lower Jurassic, where on the Lombardian basin tectonic activity modified the current marine and terrestrial habitats. Here it developed a series of marine-related depositional settings, represented by an outcrop of 550–600 m of grey Calcarenites and Calcilutites with chert lenses and marly interbeds, that recovers the Sedrina, Moltrasio and Domaro Formations. This was mostly due to the post-Triassic crisis, that was linked locally to tectonics. The Moltrasio Formation is considered a continuation of the Sedrina Limestone and the Hettangian Albenza Formation, and was probably a shallow water succession, developed on the passive margin of the westernmost Southern Alps. It is known due to the exquisite preservation observed on the Outcrop in Osteno, where several kinds of marine biota have been recovered.
Flexibilia is a superorder of specialized Paleozoic crinoids. They exhibited a conserved body plan and consistent suite of characteristics throughout their long history. Previously considered a subclass with unclear affinities, later investigation determined that flexibles are well-nested within Cladida, a broad group ancestral to living articulate crinoids. The Ordovician cladid Cupulocrinus acts as an intermediate form linking the generalized anatomy of other early cladids with the distinctive anatomy of flexibles, and several studies have considered it to be ancestral to the rest of the group. Although flexibles never reached the same abundance or diversity as many other crinoid groups, they remained a reliable component of crinoid faunas, particularly from the Silurian onwards. Flexible fossils are very rare in the Ordovician, but the Late Ordovician appears to have been an interval of rapid diversification for the group.
