| Goniodiscaster pleyadella | |
|---|---|
 | |
| Preserved specimens of Goniodiscaster pleyadella, Muséum National d'Histoire Naturelle, Paris | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Asteroidea |
| Order: | Valvatida |
| Family: | Oreasteridae |
| Genus: | Goniodiscaster |
| Species: | G. pleyadella |
| Binomial name | |
| Goniodiscaster pleyadella | |
Goniodiscaster pleyadella is a species of sea stars in the family Oreasteridae.
The Oreasteridae are a family of sea stars in the class Asteroidea.
In biology, extinction is the termination of an organism or of a group of organisms (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" after a period of apparent absence.
The IUCN Red List of Threatened Species, founded in 1965, has evolved to become the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red List are produced by countries or organizations, which assess the risk of extinction to species within a political management unit.
The conservation status of a group of organisms indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation status: not simply the number of individuals remaining, but the overall increase or decrease in the population over time, breeding success rates, and known threats. Various systems of conservation status exist and are in use at international, multi-country, national and local levels as well as for consumer use.
An endangered species is a species which has been categorized as very likely to become extinct in the near future. Endangered (EN), as categorized by the International Union for Conservation of Nature (IUCN) Red List, is the second most severe conservation status for wild populations in the IUCN's schema after Critically Endangered (CR).
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, and in a ring species. Also, among organisms that reproduce only asexually, the concept of a reproductive species breaks down, and each clone is potentially a microspecies.
Goniodiscaster is a genus of sea stars in the family Oreasteridae.
Goniodiscaster acanthodes is a species of sea stars in the family Oreasteridae.
Goniodiscaster australiae is a species of sea stars in the family Oreasteridae.
Goniodiscaster bicolor is a species of sea stars in the family Oreasteridae.
Goniodiscaster foraminatus is a species of sea stars in the family Oreasteridae.
Goniodiscaster forficulatus is a species of sea stars in the family Oreasteridae.
Goniodiscaster granuliferus is a species of sea stars in the family Oreasteridae.
Goniodiscaster vallei is a species of sea stars in the family Oreasteridae.
Goniodiscaster porosus is a species of sea stars in the family Oreasteridae.
Goniodiscaster scaber is a species of sea stars in the family Oreasteridae. Its scientific name was first published in 1859 by Karl August Möbius, who placed it in the genus Goniodiscus.
Goniodiscaster integer is a species of sea stars in the family Oreasteridae.
Goniodiscaster insignis is a species of sea stars in the family Oreasteridae.
Goniodiscaster rugosus is a species of sea stars in the family Oreasteridae.
Goniodiscaster seriatus is a species of sea stars in the family Oreasteridae.
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