Summary:
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'''Pedipalps''' (commonly shortened to '''palps''' or '''palpi''') are the second pair of [[appendage]]s of the [[prosoma]] in the subphylum [[Chelicerata]]. They are traditionally thought to be homologous with [[Mandible_(arthropod)|mandibles]] in [[Crustacea]] and [[insects]], although more recent studies (e.g. using [[Hox genes]]) suggest they are probably homologous with the crustacean second antennae.
Chelicerate pedipalps are appendages of six articles: the coxae, a single [[Trochanter (arthropod leg)|trochanter]], the [[femur]], a short [[patella]], the [[tibia]], and the [[tarsus (skeleton)|tarsus]]. In spiders the coxae frequently have extensions called [[maxilla (arthropod mouthpart)|maxilla]]e or gnathobases, which function as [[mouth]] parts with or without some contribution from the coxae of the anterior [[arthropod leg|legs]]. The limbs themselves may be simple tactile organs outwardly resembling the legs, as in [[spider]]s, or chelate weapons of great size, as in the [[scorpion]]s. Comparative studies of pedipalpal morphology may suggest that leg-like pedipalps are primitive in [[Arachnida]]. At present, the only reasonable alternative to this view is to assume that xiphosurans reflect the morphology of the primitive [[arachnid]] pedipalp and to conclude that this appendage is primitively chelate. Chelate or sub chelate pedipalps are found in several [[arachnid]] groups, i.e. [[Ricinulei]], [[Thelyphonida]], [[Scorpiones]] and [[Pseudoscorpiones]], but the chelae in most of these taxa may not be homologous with those found in [[Xiphosura]]. The pedipalps are distinctly [[raptorial]] in [[Amblypygi]], [[Thelyphonida]], [[Schizomida]] and some [[Opiliones]] belonging to the laniatorid group.
==Spider pedipalps==
Pedipalps of [[spiders]] have the same segmentation as the [[arthropod leg|legs]], but the [[tarsus (skeleton)|tarsus]] is undivided, and the pretarsus has no lateral claws. In [[sexually mature]] male spiders, the final segment of the pedipalp, the tarsus, develops into a complicated structure (sometimes called the palpal organ or bulb) that is used to transfer sperm to the female seminal receptacles during mating. The details of this structure vary considerably between different groups of spiders and are useful for identifying species.
The '''cymbium''' is a spoon-shaped structure located at the end of the spider pedipalp that supports the palpal organ. The cymbium may also be used as a [[stridulatory organ]] in spider courtship.
{{GFDL}}
'''Pedipalps''' (commonly shortened to '''palps''' or '''palpi''') are the second pair of [[appendage]]s of the [[prosoma]] in the subphylum [[Chelicerata]]. They are traditionally thought to be homologous with [[Mandible_(arthropod)|mandibles]] in [[Crustacea]] and [[insects]], although more recent studies (e.g. using [[Hox genes]]) suggest they are probably homologous with the crustacean second antennae.
Chelicerate pedipalps are appendages of six articles: the coxae, a single [[Trochanter (arthropod leg)|trochanter]], the [[femur]], a short [[patella]], the [[tibia]], and the [[tarsus (skeleton)|tarsus]]. In spiders the coxae frequently have extensions called [[maxilla (arthropod mouthpart)|maxilla]]e or gnathobases, which function as [[mouth]] parts with or without some contribution from the coxae of the anterior [[arthropod leg|legs]]. The limbs themselves may be simple tactile organs outwardly resembling the legs, as in [[spider]]s, or chelate weapons of great size, as in the [[scorpion]]s. Comparative studies of pedipalpal morphology may suggest that leg-like pedipalps are primitive in [[Arachnida]]. At present, the only reasonable alternative to this view is to assume that xiphosurans reflect the morphology of the primitive [[arachnid]] pedipalp and to conclude that this appendage is primitively chelate. Chelate or sub chelate pedipalps are found in several [[arachnid]] groups, i.e. [[Ricinulei]], [[Thelyphonida]], [[Scorpiones]] and [[Pseudoscorpiones]], but the chelae in most of these taxa may not be homologous with those found in [[Xiphosura]]. The pedipalps are distinctly [[raptorial]] in [[Amblypygi]], [[Thelyphonida]], [[Schizomida]] and some [[Opiliones]] belonging to the laniatorid group.
==Spider pedipalps==
Pedipalps of [[spiders]] have the same segmentation as the [[arthropod leg|legs]], but the [[tarsus (skeleton)|tarsus]] is undivided, and the pretarsus has no lateral claws. In [[sexually mature]] male spiders, the final segment of the pedipalp, the tarsus, develops into a complicated structure (sometimes called the palpal organ or bulb) that is used to transfer sperm to the female seminal receptacles during mating. The details of this structure vary considerably between different groups of spiders and are useful for identifying species.
The '''cymbium''' is a spoon-shaped structure located at the end of the spider pedipalp that supports the palpal organ. The cymbium may also be used as a [[stridulatory organ]] in spider courtship.
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