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One of the locations from which Agaricocrinus americanus is known is the Edwardsville Formation, in the vicinity of Crawfordsville, Montgomery County, Indiana, in the United States. In this fossil-rich bed have been found the fossils of sixty species of crinoid, distributed among more than forty genera.
While it has been known that stalked crinoids could move, before this recording the fastest motion known for a stalked crinoid was 0.6 metres (2 feet) per hour. The 2005 recording showed one of these moving across the seabed at the much faster rate of 4 to 5 cm (1.6 to 2.0 in) per second, or 144 to 180 m (472 to 591 ft) per hour.
Scyphocrinus, is an extinct genus of crinoids.Species belonging to this genus lived during the Silurian and Devonian periods (from 443.4 to 358.9 Ma). [1] [2]The crinoid genus Camarocrinus have been considered by some authors the bulbous distal end of the stem of Scyphocrinus, having the function of a root and fixing the crinoid to the sea button.
Articulata are a subclass or superorder within the class Crinoidea, including all living crinoid species. They are commonly known as sea lilies (stalked crinoids) or feather stars (unstalked crinoids). The Articulata are differentiated from the extinct subclasses by their lack of an anal plate in the adult stage and the presence of an ...
Fossil crinoid. This list of crinoid genera is an attempt to create a comprehensive listing of all genera that have ever been considered to be crinoids, excluding purely vernacular terms.
Pentacrinites are commonly found in the Pentacrinites Bed of the Early Jurassic (Lower Lias) of Lyme Regis, Dorset, England. [2] Pentacrinites can be recognized by the extensions (or cirri) all around the stem, which are long, unbranching, and of increasing length further down, the very small cup and 5 long freely branching arms.
Flexible fossils are very rare in the Ordovician (the most common taxa being Cupulocrinus and Protaxocrinus), but the Late Ordovician appears to have been an interval of rapid diversification for the group. [3] Major traits of Flexibilia include: [1] [4] Three infrabasal plates (in contrast to the five found in other dicyclic crinoids).
It is known that the arms could shut tightly in life (most Encrinus fossils are found in this position), but it is difficult to estimate the greatest angle at which they could open. It is possible that specimens recorded as being widest open demonstrate the normal angle of opening in life. [ 3 ]