Pedipalp

Source: Wikipedia, the free encyclopedia.
This article is about chelicerate pedipalps. For Lepidoptera palpi, see External morphology of Lepidoptera § Palpi.
Male striped lynx spider showing enlarged pedipalps
Green shaded pedipalps in an illustrated dorsal view of a whip scorpion

Pedipalps (commonly shortened to palps or palpi) are the secondary pair of forward appendages among chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and anterior to the first pair of walking legs.

Overview

Pedipalps are composed of six segments or articles. From the proximal end (where they are attached to the spider) to the distal, they are: the coxa, the trochanter, the femur, the short patella, the tibia, and the tarsus. In spiders, the coxae frequently have extensions called maxillae or gnathobases, which function as mouth parts with or without some contribution from the coxae of the anterior legs. The limbs themselves may be simple tactile organs outwardly resembling the legs, as in spiders, or chelate weapons (pincers) of great size, as in scorpions. The pedipalps of Solifugae are covered in setae, but have not been studied in detail.[1]

Comparative studies of pedipalpal morphology may suggest that leg-like pedipalps are

antennae
.

Chelate pedipalps

Chelate or sub-chelate (pincer-like) pedipalps are found in several arachnid groups (Ricinulei, Uropygi, scorpions and pseudoscorpions) but the chelae in most of these groups may not be homologous with those found in Xiphosura. The pedipalps are distinctly raptorial (i.e., modified for seizing prey) in the Amblypygi, Uropygi, Schizomida, and some Opiliones belonging to the laniatorid group.[citation needed]

Spider pedipalps

Unicorn catleyi

Pedipalps of

sexually mature male spiders, the final segment of the pedipalp, the tarsus, develops a complicated structure (sometimes called the palpal bulb or palpal organ) 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.[3][4] The pedipalps are also used by male spiders in courtship displays, contributing to vibratory patterns in web-shaking, acoustic signals, or visual displays.[5]

The

stridulatory organ in spider courtship.[6]

The embolus is a narrow whip-like or leaf-like extension of the palpal bulb.

References

  1. S2CID 86837385
    . Retrieved 5 September 2020.
  2. ^ "Spider specifics". Smithsonian Education (lesson plan). Under the spell of spiders. Washington, DC: Smithsonian Institution.
  3. ^ a b Comstock, John Henry (1920) [1912]. The Spider Book. Doubleday, Page & Company. pp. 106–121.
  4. ISBN 978-0-19-509594-4
    – via Internet Archive (archive.org).
  5. PMID 20696272
    . Retrieved 20 August 2020.
  6. PMID 16513934. See Fig 6 – SEM of tibio-cymbial joint on the male palp of S. stridulans

Further reading

External links
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