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Eucladida
Cladida is a major subgroup of crinoids with a complicated taxonomic history. Cladida was originally applied to a wide assortment of extinct crinoids with a dicyclcic calyx. Under this original definition, cladids would represent a paraphyletic order ancestral to several other major crinoid groups, particularly the living Articulata. More recently, Cladida has been redefined as a monophyletic parvclass of pentacrinoids which encompasses articulates and the extinct Flexibilia (flexibles). Cladids also include various minor taxa such as the hybocrinids and " cyathocrines". As flexibles were not originally considered cladids, the new subgroup Eucladida has been erected for cladids which are more derived than flexibles. Cladida is the sister group to Disparida, another large group of extinct crinoids. Taxonomy * Parvclass Cladida ** Superorder † Porocrinoidea *** Order † Hybocrinida *** Order † Porocrinida ** Superorder †Flexibilia *** Order † Sagenocrinida *** Order � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crinoid
Crinoids are marine animals that make up the Class (biology), class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are members of the largest crinoid Order (biology), order, Comatulida. Crinoids are Echinoderm, 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 as great as . Adult crinoids are characterised by having the mouth located on the upper surface. This is surrounded by feeding arms, and is linked to a U-shaped gut, with the anus being located on the oral disc near the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognised, in most crinoids the five arms are subdivided into ten or more. These have feathery pinnules and are spread wide to gather planktonic particles from the water. At som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ulrichicrinus Coryphaeus
''Ulrichicrinus'' is an extinct genus of crinoids. Fossil records This genus is known in the fossil records of the Carboniferous period of United States (age range: from 345.3 to 342.8 million years ago). References * See also List of crinoid genera 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. The list includes all commonly accepted genera, but also genera that ar ... Cladida Prehistoric crinoid genera {{paleo-crinoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disparida
Disparida is an parvclass of extinct marine animals in the class Crinoidea. Disparids are a speciose and morphologically diverse group of crinoids distinguished by their monocyclic calyx and slender arms without pinnules. They range from the Early Ordovician (Tremadocian) to Middle Permian, reaching their highest diversity during the Late Ordovician. While many disparids had a generalized shape typical of other stalked crinoids, some subgroups achieved strange forms. The long-lasting Calceocrinidae were recumbent forms, with a flattened crown bent back onto a stalk which rested on the seafloor. Other unusual disparid families include the armless Zophocrinidae, the spiral-armed Myelodactylidae, and the diminutive, simplified Pisocrinidae. Disparids have long been classified by the structure of their radial plates and different planes of symmetry, but a cumulative phylogenetic approach has failed to confirm the validity of many proposed subgroups. Nevertheless, Disparida itsel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyrtocrinida
Cyrtocrinida is an order of sea lilies which contains two suborders and three families. Characteristics Members of this order have stems consisting of a single skeletal unit or a very small number of units. There are no cirri, and the expanded base of the stem attaches directly to the substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo .... The calyx may be asymmetrical and consists of five arms attached to five radial ossicles. The arms subdivide at arm ossicle I or II. Families The World Register of Marine Species includes the following groups in the order: * Suborder Cyrtocrinina ** Family Sclerocrinidae Jaekel, 1918 * Suborder Holopodina ** Family Eudesicrinidae Bather, 1899 ** Family Holopodidae Zittel, 1879 References Articulata (Crinoidea) Echinoderm or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comatulida
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. Taxonomy Bourgueticrinida, the sea lilies, has traditionally been viewed as an order of Articulata and a sister taxon to Comatulida. A study published in 2011 suggested that it should be renamed Bourgueticrinina and viewed as a suborder of Comatulida. Characteristics Like other echinoderms, comatulids have pentamerous symmetry (five sided) as adults though the larvae have bilateral symmetry. Late in their development, the larvae are attached to the seabed by a stalk, but this is broken at metamorphosis and the juvenile crinoid is free living. The body has an endoskeleton made from a number of articulated calcareous plates known as ossicles covered by a thin e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Millericrinida
Millericrinida is an order of articulate crinoids that originated in the Anisian In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ... (Middle Triassic). References Articulata (Crinoidea) Anisian first appearances Extant Middle Triassic first appearances Prehistoric animal orders Echinoderm orders {{crinoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
