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Oonopidae
Oonopidae is a family of spiders commonly known as goblin spiders, consisting of over 1,600 described species in about 110 genera worldwide,〔 with total species diversity estimated at 2000 to 2500 species. The type genus of the family is ''Oonops'' Keyserling, 1835. They are generally tiny (1-3 mm) haplogyne araneomorph spiders. Some have hardened plates (scuta) on their abdomens. Oonopids usually have six eyes, the anterior median eyes having been lost. However, four-eyed (''Opopaea viamao''), two-eyed (e.g. ''Coxapopha'', ''Diblemma'') and even completely eyeless species (e.g. ''Cousinea'', the cave-dwelling ''Blanioonops'') are also known. The family is permeated with unusual morphological traits, many of which are limited to males. Examples include heavily modified mouthparts (e.g. ''Coxapopha'', ''Xyccarph''), sternal pouches (sometimes alternatively called holsters; e.g. ''Grymeus'') and extensions of the carapace (e.g. ''Ferchestina'', ''Unicorn''). The male pedipalps are also often highly modified. The genus ''Opopaea'', for example, exhibits an expanded palpal patella while male ''Ischnothyreus'' are characterized by completely sclerotized, pitch-black pedipalps. Members of the genus ''Orchestina'' are believed to be able to jump, as both sexes have greatly enlarged femora on the fourth leg pair. Oonopidae are seldom seen by people as they are too small to be easily noticed. Generally, oonopid spiders are found in the leaf litter layer and under rocks, but they also constitute a significant component of the spider fauna living in the canopy of tropical rain forests. Three blind Afrotropical genera (''Anophthalmoonops'', ''Caecoonops'', ''Termitoonops'') are exclusively found in termite nests. A few species, such as the pantropical ''Heteroonops spinimanus'', are thought to be parthenogenetic as no males have yet been collected.
== Fossil record ==
Oonopidae are frequently encountered as subfossils preserved in copals and as fossils preserved in amber. Oonopids even occur in more amber deposits than any other spider family, which may be accounted for by their widespread distribution, small size, and wandering behaviour, as amber appears to be biased towards trapping such spiders. In contrast, sedimentary fossils of Oonopidae are unknown.
Most fossil oonopids described from amber are assigned to the extant genus ''Orchestina''. This genus was already widespread by the end of the Cretaceous, as indicated by specimens found in amber dating back approximately 100 million years. This makes ''Orchestina'' the oldest extant spider genus along with the Archaeidae. ''Orchestinas fossil record even includes a pair of spiders that were entombed during copulation.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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