Pedipalps

Template:Auto images

Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of the prosoma in the subphylum Chelicerata. They are traditionally thought to be homologous with 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, the femur, a 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 of great size, as in the scorpions. 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 legs, but the 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.[1][2]

The cymbium is a spoon-shaped structure located at the end of the spider pedipalp that supports the palpal organ.[1] The cymbium may also be used as a stridulatory organ in spider courtship.[3]

References

  • Savory, T. 1977. Arachnida. 2nd edition. U.S. Edition published by Academic Press INC. LTD.340 pp.
  • Snodgrass, R. E. 1971. A Textbook Arthropod Anatomy. Published by Hafner Publishing Company, INC. 363 pp.
  • Torre-Bueno, J. R. 1989. The Torre-Bueno Glossary of Entomology compiled by Stephen W. Nichols; including Supplement A by George S. Tulloch. Published by The New York Entomological Society in cooperation with the American Museum of Natural History. 840 pp.

External links

  • Several close-up photos of a tarantula creating a sperm web - Brachypelma Vagans (Mexican Red-rump)
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.