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Parvulastra
''Parvulastra'' is a genus of starfish belonging to the family Asterinidae. The species of this genus are found in Southern Hemisphere. The genus shows an unusual reproductive mode within Asterinidae: ''Parvulastra parvivipara'' and '' Parvulastra vivipara'' are viviparous. Prior to their description as distinct species, they were considered variants of '' Parvulastra exigua'', which has free-living (but non-feeding) larvae. Species There are five species: *'' Parvulastra calcarata'' *'' Parvulastra dyscrita'' *'' Parvulastra exigua'' *''Parvulastra parvivipara ''Parvulastra parvivipara'' is a very small species of starfish in the family Asterinidae. It is a viviparous species and gives birth to live young. It lives in rock pools on intertidal granite rocks in a limited area of South Australia. Descrip ...'' *'' Parvulastra vivipara'' References Asterinidae Asteroidea genera {{asteroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parvulastra Calcarata
''Parvulastra'' is a genus of starfish belonging to the family Asterinidae. The species of this genus are found in Southern Hemisphere. The genus shows an unusual reproductive mode within Asterinidae: ''Parvulastra parvivipara'' and '' Parvulastra vivipara'' are viviparous. Prior to their description as distinct species, they were considered variants of '' Parvulastra exigua'', which has free-living (but non-feeding) larvae. Species There are five species: *'' Parvulastra calcarata'' *'' Parvulastra dyscrita'' *'' Parvulastra exigua'' *''Parvulastra parvivipara ''Parvulastra parvivipara'' is a very small species of starfish in the family Asterinidae. It is a viviparous species and gives birth to live young. It lives in rock pools on intertidal granite rocks in a limited area of South Australia. Descrip ...'' *'' Parvulastra vivipara'' References Asterinidae Asteroidea genera {{asteroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parvulastra Exigua
''Parvulastra exigua'', or the dwarf cushion starJones, Georgina. ''A field guide to the marine animals of the Cape Peninsula.'' SURG, Cape Town, 2008. is a species of sea star in the family Asterinidae. It can be found in temperate intertidal marine communities from geographically widespread sites around the southern hemisphere (including South Africa and Australia). Description ''Parvulastra exigua'' has pentagonal body with no obvious protruding arms. Dorsal surface is tiled with a small cluster of spines at each tile. Colour is variegated, with bright patterns in orange, brown, green and white. Distribution ''Parvulastra exigua'' is found from Namibia to Mozambique on intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...s up to 3 m, on St Helena, St Paul, and so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parvulastra Parvivipara
''Parvulastra parvivipara'' is a very small species of starfish in the family Asterinidae. It is a viviparous species and gives birth to live young. It lives in rock pools on intertidal granite rocks in a limited area of South Australia. Description Adults of ''P. parvivipara'' can grow to a diameter of about and are an orange-yellow colour. They are the smallest known starfish. Distribution and habitat ''P. parvivipara'' is endemic to the coast of South Australia, where it is found within of the Eyre Peninsula. Its distribution is limited to intertidal rock pools on granite rocks. Some seemingly suitable pools contain none of these starfish, while others have large numbers. Starfish favoured pools with little wave action, but with a considerable degree of biodiversity. They also preferred pools low down the beach rather than high-level pools. Lifecycle ''P. parvivipara'' has a very unusual lifecycle for a starfish. The adults are self-fertilising hermaphrodites and the eggs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parvulastra Vivipara
''Parvulastra vivipara'', the Tasmanian live-bearing seastar, is a tiny, uniformly orange-yellow seastar, up to across. The species usually has five short arms and is a rounded, pentagon shape. Morphological variation is common and three, four or six arms are occasionally present. It is endemic to coastal waters in southeast Tasmania. Description ''P. vivipara'' is a very small, cushiony seastar with a maximum diameter of . It is normally pentagonal in shape, with five stubby arms, but individuals sometimes occur with four or six arms. The aboral (upper) surface is a plain yellowish-orange. Distribution and habitat ''P. vivipara'' is endemic to the waters of south-eastern Tasmania. It is known from thirteen separate locations and because there is no planktonic larval stage, this species has limited scope for dispersal. Its total area of occupation is estimated to be under . One of these locations was as a result of an accidental introduction in 1995 when an aquarium population ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parvulastra Dyscrita
''Parvulastra dyscrita'' is a species of starfish belonging to the family Asterinidae The Asterinidae are a large family of sea stars in the order Valvatida. Description and characteristics These are generally small sea stars, flattened dorsally and bearing very short arms, often giving a pentagonal shape in the body ;example: .... The species is found in Southern Africa. References Asterinidae Fauna of the Atlantic Ocean Fauna of the Indian Ocean Animals described in 1923 Taxa named by Hubert Lyman Clark {{Asteroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterinidae
The Asterinidae are a large family of sea stars in the order Valvatida. Description and characteristics These are generally small sea stars, flattened dorsally and bearing very short arms, often giving a pentagonal shape in the body ;example: ''Asterians rubens'' (except in some species possessing more than five arms). The periphery of the body is thin and formed by indistinct, tiny marginal plates. They are characterized by their aborale face formed by plates shaped like crescents, sometimes giving a "knitted" appearance to the skin. The abyssal species can be bigger, like those of the genus '' Anseropoda'', which can exceed 45 cm in diameter. Biology Most of the species are small and relatively cryptic: they are often found hidden under rocks or in crevices, for example. Several species have access to a fissiparous asexual reproduction, multiplying their reproductive potential. For that reason, some species of the genera '' Meridiastra'' and '' Aquilonastra'' can so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starfish
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish are also known as asteroids due to being in the class Asteroidea. About 1,900 species of starfish live on the seabed in all the world's oceans, from warm, tropical zones to frigid, polar regions. They are found from the intertidal zone down to abyssal depths, at below the surface. Starfish are marine invertebrates. They typically have a central disc and usually five arms, though some species have a larger number of arms. The aboral or upper surface may be smooth, granular or spiny, and is covered with overlapping plates. Many species are brightly coloured in various shades of red or orange, while others are blue, grey or brown. Starfish have tube feet operated by a hydraulic system and a mouth at the centre of the oral or lower surface. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viviparous
Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the mother. The term 'viviparity' and its adjective form 'viviparous' derive from the Latin ''vivus'' meaning "living" and ''pario'' meaning "give birth to". Reproductive mode Five modes of reproduction have been differentiated in animals based on relations between zygote and parents. The five include two nonviviparous modes: ovuliparity, with external fertilisation, and oviparity, with internal fertilisation. In the latter, the female lays zygotes as eggs with a large yolk; this occurs in all birds, most reptiles, and some fishes. These modes are distinguished from viviparity, which covers all the modes that result in live birth: *Histotrophic viviparity: the zygotes develop in the female's oviducts, but find their nutrients by oophagy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
