Chaeta

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Related to chaetae: setae

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 ?
Spermathecal chaetae trivial (nib-shaped, distal portion with parallel edges, not twisted).
Comparison: New material mostly corresponding with original description and paratype examined (Day 1957); in the paratype the last 12 chaetigers are abranchiate, falling within the range observed in the new material, posterior inferior companion chaetae are not mentioned in the description but are present in both the new material and the paratype, although they are present on fewer chaetigers in the latter.
Coxae of legs I, II, and III with 3, 9, and 12 chaetae, respectively, trochanters with 9 chaetae each, and femora with 15 chaetae each.
tenuis at 10-13[degrees]C Event Time Fertilization 0 First polar body 30 min First cleavage 2 h 15 min Second cleavage 3 h Third cleavage 3 h 45 min Ciliogenesis 15 h Swimming blastulae 16 h Gastrulation ~24 h Episphere eyespots ~42-48 h Feeding ~70-75 h Telotroch ~16 d First accessory eyespot ~24-30 d Chaetae ~24-30 d Metamorphosis ~35 d After the onset of feeding at 70-75 h, development rate varies substantially among cultures; times recorded are for rapidly developing cultures.
First three parapodia reduced, with two or three spinigerous chaetae and no cirri (Fig.
Chaetae before clitellum by 3-4(5), backwards by 2-3, straight or slightly bent, tapering, sharp-tipped, 28-84 (most often 40-50) [micro]m long (Fig.
At the same time, we might have to reconsider the early proposal by Pruvot & Racovitza (1895:422) about the specific characters such as pigmentation pattern, length of antennae, their relative articulation, start of branchiae and their maximal filament number (size-dependent), type of pectinate chaetae, blade relative size features in compound falcigers, form and shape of the subacicular hooks, number of abranchiate posterior chaetigers, and number and length of anal cirri.
2D, E); bearing about 30 crenulated capillaries in anterior abdomen and about 15 in median abdomen, furcated chaetae not seen; prechaetal lobe supported by one or two slightly sigmoid and protruding aciculae.
16), with the principal sensory chaetae enclosed in the membrane-skin.
Common to all individuals was the lack of chaetae and the lack of segments within the roots region or following it.
longicornis: the presence of triangular subterminal processes in the spiniger-like compound chaetae of chaetiger one.