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Aporometridae
Aporometridae is a monotypic family of crinoids, the only genus being ''Aporometra'', which contains three species, all endemic to the seas around Australia. Description Members of this family have five arms which subdivide near the base giving them ten arms in total. The arms can reach in length and at the base of the calyx there are up to 25 cirri, often longer than the arms. Unique among Comatulida, the cirri are flattened on the underside. The gonads are located on the pinnules and not on the arms, and the embryos are brooded in cavities in the arms. Species The World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialis ... lists the following species in this genus: * '' Aporometra occidentalis'' HL Clark, 1938 * '' Aporometra paedophora'' (HL Clar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aporometridae
Aporometridae is a monotypic family of crinoids, the only genus being ''Aporometra'', which contains three species, all endemic to the seas around Australia. Description Members of this family have five arms which subdivide near the base giving them ten arms in total. The arms can reach in length and at the base of the calyx there are up to 25 cirri, often longer than the arms. Unique among Comatulida, the cirri are flattened on the underside. The gonads are located on the pinnules and not on the arms, and the embryos are brooded in cavities in the arms. Species The World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialis ... lists the following species in this genus: * '' Aporometra occidentalis'' HL Clark, 1938 * '' Aporometra paedophora'' (HL Clar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aporometra Occidentalis
Aporometridae is a monotypic family of crinoids, the only genus being ''Aporometra'', which contains three species, all endemic to the seas around Australia. Description Members of this family have five arms which subdivide near the base giving them ten arms in total. The arms can reach in length and at the base of the calyx there are up to 25 cirri, often longer than the arms. Unique among Comatulida, the cirri are flattened on the underside. The gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...s are located on the pinnules and not on the arms, and the embryos are brooded in cavities in the arms. Species The World Register of Marine Species lists the following species in this genus: * '' Aporometra occidentalis'' HL Clark, 1938 * '' Aporometra paedophora'' (HL ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aporometra Wilsoni
''Aporometra wilsoni'' is a marine invertebrate, a species of crinoid or feather star in the family Aporometridae. It is found in shallow water around the coasts of southern Australia. Description This is a small species of crinoid with arms up to long. The five arms each divide close to the base giving ten arms in total, with feather-like pinnules fanning out on either side. There are also up to 25 unusual cirri with flattened undersides which may be longer than the arms. Both the gonads, and the chambers in which the larvae are brooded, are located on the pinnules in this species. Distribution This crinoid is native to the southern coasts of Australia. Its range extends from Elizabeth Reef, Perth, Western Australia, to Gabo Island, Victoria, at depths down to about . Ecology ''Aporometra wilsoni'' is found living in close association with brown algae such as '' Cystophora'' and '' Sargassum''. Crinoids are dioecious, with separate male and female individuals. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aporometra Paedophora
''Aporometra paedophora'' is a marine invertebrate, a species of crinoid or feather star in the family Aporometridae. It was first found at a depth of 22 fathoms (40.2 m) off the Manning River on the New South Wales coast. Other specimens were found off the coast of Bunbury, Western Australia at depths between 9 and 15 m (but these have since been identified as ''Aporometra wilsoni''). Based on morphological evidence of four (somewhat degraded) specimens of ''A. paedophora'' (all paratypes), Helgen & Rouse believe that this may not be a separate species from ''Aporometra wilsoni''. Description Plate XLVII shows three types of pinnules: first, second and distal pinnules (Figs 4-6), and pentacrinoid larvae (Figs 7-9) from youngest to oldest. Fig 10 shows a cirrus. In the earliest free-swimming stage, the arms are about 7 mm long and have about nine pinnules on each side. This is a small species of crinoid with arms up to long. All Clark's large specimens carried pentacrinoid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Articulata (Crinoidea)
Articulata are a subclass or superorder within the class Crinoidea, including the only 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 entoneural system. Articulata first appeared in the fossil record during the Triassic period although other, now extinct crinoid groups, originated in the Ordovician. Characteristics Articulata exhibit pentamerous symmetry. The stalk, which consists of numerous disks held together by ligaments, supports a calyx or cup made of circlets of calcerous plates. In Comatulids, the stalk develops following the larval stage, but the juveniles shed all but the topmost disk to take up a free-living existence. Five often branched arms, which consist of articulated series of ossicles, extend from the oral plate and form the food-capture mechanism of Articula ... [...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] |
Gonad
A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells. Both of these gametes are haploid cells. Some hermaphroditic animals have a type of gonad called an ovotestis. Evolution It is hard to find a common origin for gonads, but gonads most likely evolved independently several times. Regulation The gonads are controlled by luteinizing hormone and follicle-stimulating hormone, produced and secreted by gonadotropes or gonadotrophins in the anterior pituitary gland. This secretion is regulated by gonadotropin-releasing hormone produced in the hypothalamus. Development Gonads start developing as a common primordium (an organ in the earliest stage of development), in the form of genital ridges, which are only l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinoderm Families
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian. The echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. Most echinoderms are able to reproduce asexually and regenerate tissue, organs, and limbs; in some cases, they can undergo complete regeneration from a single limb. Geolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Register Of Marine Species
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the information, which is gathered from the primary scientific literature as well as from some external regional and taxon-specific databases. WoRMS maintains valid names of all marine organisms, but also provides information on synonyms and invalid names. It is an ongoing task to maintain the registry, since new species are constantly being discovered and described by scientists; in addition, the nomenclature and taxonomy of existing species is often corrected or changed as new research is constantly being published. Subsets of WoRMS content are made available, and can have separate badging and their own home/launch pages, as "subregisters", such as the ''World List of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinnule
A leaflet (occasionally called foliole) in botany is a leaf-like part of a compound leaf. Though it resembles an entire leaf, a leaflet is not borne on a main plant stem or branch, as a leaf is, but rather on a petiole or a branch of the leaf. Compound leaves are common in many plant families and they differ widely in morphology. The two main classes of compound leaf morphology are palmate and pinnate. For example, a ''hemp'' plant has palmate compound leaves, whereas some species of ''Acacia'' have pinnate leaves. The ultimate free division (or leaflet) of a compound leaf, or a pinnate subdivision of a multipinnate leaf is called a pinnule or pinnula. Image:Ветвь акации.jpg, Pinnate leaf of a legume with 10 leaflets Image:Mimosa Pudica.gif, ''Mimosa pudica'' folding leaflets inward. See also * Compound leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosyn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemism
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cirrus (biology)
In biology, a cirrus , plural ''cirri'', , (from the Latin ''cirrus'' meaning a ''curl-like tuft or fringe'') is a long, thin structure in an animal similar to a tentacle but generally lacking the tentacle's strength, flexibility, thickness, and sensitivity. In the sheep liver fluke, for example, the ''cirrus'' is the worm's muscular penis and when not in use is retained within a ''cirrus sac'' or ''pouch'' near the animal's head. The same structure exists in the various ''Taenia'' species of tapeworm. In the clam worms, however, the cirrus is the tentacular process or growth on each of the feet (''parpodia''), either the ''dorsal cirrus'' or the ''ventral cirrus'', and has nothing to do with reproduction. Among the bristleworms, a cirrus is a tentacular growth near the head or notopodium containing sense organs and may be either dorsal, ventral, or lamellar. Among the ribbonworms, the ''caudal cirrus'' is a small thread-like growth at the posterior end of the worm. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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