Malleolus (arthropod)

Depiction of Rhagodima nigrocincta (a type of solifugid) showing malleoli on last pair of legs

Ventral view of a solifuge, with malleoli visible

Detail of malleoli on a solifuge

A malleolus (plural: malleoli) is a fan-shaped chemoreceptor or racquet organ, an array of which are carried in pairs on the ventral or undersides of Solifugae. ^[1] They are the counterpart of pectines in scorpions, and modified walking limbs in the uropygids and amblypygids as well as the pedipalps in spiders and other arachnids. ^{[2] [3]} Generally, solifuges have five pairs of malleoli on the ventral surface of the fourth pair of legs. Malleoli are usually larger in males. ^[4] A malleolus comprises a basal stalk and a triangular fan, with epicuticular protrusions on each anterior face, and granular structures on each stalk, with undulate surfaces at each distal end.

References

1. Mullen, Gary R. (2019-01-01), Mullen, Gary R.; Durden, Lance A. (eds.), "Chapter 24 - Solpugids (Solifugae)", Medical and Veterinary Entomology (Third Edition), Academic Press, pp. 505–506, doi:10.1016/b978-0-12-814043-7.00024-8, ISBN   978-0-12-814043-7 , retrieved 2025-02-06
2. Brownell, Philip H. (1998). "Glomerular Cytoarchitectures in Chemosensory Systems of Arachnidsa". Annals of the New York Academy of Sciences. 855 (1): 502–7. Bibcode:1998NYASA.855..502B. doi:10.1111/j.1749-6632.1998.tb10614.x. PMID   10049228. S2CID   31197930.
3. Brownell, Philip H.; Farley, Roger D. (1974). "The organization of the malleolar sensory system in the solpugid, Chanbria sp". Tissue and Cell. 6 (3): 471–85. doi:10.1016/0040-8166(74)90039-1. PMID   4432235.
4. Sombke, Andy; Klann, Anja E.; Lipke, Elisabeth; Wolf, Harald (2019). "Primary processing neuropils associated with the malleoli of camel spiders (Arachnida, Solifugae): a re-evaluation of axonal pathways". Zoological Letters. 5 (1): 26. doi: 10.1186/s40851-019-0137-z . ISSN   2056-306X. PMC   6679463 . PMID   31388441.

Further reading

• Babu, K. 1965. Anatomy of the central nervous system of arachnids. Zoologische Jahrbücher, Anatomie und Ontogenie 82: 1–154.
• Bernard, H. M. 1896. The comparative morphology of the Galeodidae. Transactions of the Linnean Society. 2d Series. Zoology 6: 305–417.*Brownell, P. H. and R. D. Farley. 1974. The organization of the malleolar sensory system in the solpugid, Chanbria sp. Tissue & Cell 6: 471–485. CrossRef, PubMed
• Harvey, M. S. 2003. Catalogue of the Smaller Arachnid Orders of the World. CSIRO Publishing, Collingwood Victoria, Australia.
• Koç, H. 2007. The solifuges (Arachnida: Solpugida) fauna of southeast Anatolia: systematic zoogeography and ecology, PhD thesis, Ege University, İzmir, 241 pp. [in Turkish]
• Muma, M. H. (1951). "The Arachnid order Solpugida in the United States". Bulletin of the American Museum of Natural History. 97: 35–141.
• Punzo, F. 1998. The Biology of Camel-spiders (Arachnida, Solifugae). Kluwer Academic Publishers, Boston, MA. 301 pp. CrossRef
• Ruhlemann, H. 1908. Uber die Facherorgane, sog. Malleoli oder Raquettes coxales, des vierten Beinpaares der Solpugiden. Zeitschrift fr wissenschaftliche Zoologie 91: 599–639.
• Nazife Yiğit, Melek Erdek, Halil Koç, and Abdullah Melekoğlu. 2011. Morphological Comparison of the Malleoli (Racquet Organs) in Biton zederbaueri and Gluviopsilla discolor (Daesiidae, Solifugae)