Chaeta


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chaeta

[′kēd·ə]
(biology)

Chaeta

 

one of numerous movable hairlike pectinate or hooked protuberances of the cuticle in invertebrates. Chaetae have many purposes. In some invertebrates they help support the body during digging (Echiuroidae, many annelid worms, Pogonophora) or crawling (annelid worms). In other invertebrates it serves a protective function (certain polychaetes and brachiopods), and in still others it is used in capturing prey (chaetognaths). In polychaetes, the chaetae are part of the primitive extremities—parapodia. Each chaeta consists of a single cell on the floor of a cutaneous invagination. The chaetae of arthropods are hairlike or feathery protuberances of the chitinous cuticle; they are sense organs (mainly of touch) and sometimes help protect the body, especially the wings, from excessive wetness. Some ticks and mites still preserve primitive metamerism in the arrangement of their chaetae.

References in periodicals archive ?
Ant IV with bilobed apical vesicle with additional bifurcate chaeta beside it.
16) Tip of Ant III, showing the special chaetae or sensillae; (17) Tip of Ant IV; (18) Labrum, showing prelabral and labral chaetae, and labral papillae; (19) Terminal chaeta of labial papilla E; (20) Female genital plate; (21) Claw of foreleg; (22) Claw of medial leg; (23) Claw of hind leg.
Maxillary outer lobe with simple palp, basal chaeta and with two sublobal hairs.
tergum I with 7-9+7-9 chaetae, chaeta m absent (i2-, Th.
The genus is characterized by the shape of the postantennal organ with numerous (11-20), compound vesicles, antennal III sense organ with 5 papillae and 2 ribbed sensory clubs, the presence of the chaeta d0 on head and chaeta p0 on abdominal tergum IV, abdominal tergum VI with 1 medial chaeta, tibiotarsal distal whorl with 9 chaetae, furcal area with 2+2 chaeta in 1 row (Weiner 1996; Pomorski 1998) and usually 2 manubrial rows mm and mp, chaetae from the ma row displaced on the level of dental microchaetae, male ventral organ usually present and anal spines absent.