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One of a layer of flagellated cells lining the body cavity of a sponge and characterized by a collar of cytoplasm surrounding the flagellum. Also called collar cell.

[Greek khoanē, funnel (from khein, to pour; see gheu- in Indo-European roots) + -cyte.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Zoology) any of the flagellated cells in sponges that maintain a flow of water through the body. A collar of protoplasm surrounds the base of the flagellum. Also called: collar cell
[C19: from Greek khoanē funnel (from khein to pour) + -cyte]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.choanocyte - any of the flagellated cells in sponges having a collar of cytoplasm around the flagellumchoanocyte - any of the flagellated cells in sponges having a collar of cytoplasm around the flagellum; they maintain a flow of water through the body
flagellated cell - any cell or one-celled organism equipped with a flagellum
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References in periodicals archive ?
Summary: TEHRAN (FNA)- New findings challenge the long-standing idea that multi-celled animals evolved from a single-celled ancestor resembling a modern sponge cell known as a choanocyte.
Amazingly, half of the sponge's choanocyte (filtration) cells had divided and the choanocyte's cell division cycle was a phenomenally short 5.4 hours.
Darn gweddol hir tebyg i wallt ydi fflagelwm sy'n sownd i un pen o'r celloedd yma, ac wrth i hwn symud, mae'n creu cerrynt; felly os oes ganddoch lwyth o'r celloedd bach yma (choanocyte ydi eu henw nhw gyda llaw) maen nhw'n creu digon o gerrynt i dynnu dwr drwy'r cawg, ac ar yr un pryd maen nhw'n hidlo darnau bach o fwyd, a'i dynnu i mewn i'r celloedd.
In other words, the HMA sponges appear to be less well "irrigated." The narrower canals and smaller choanocyte chambers may result in a reduced water flow when compared to LMA sponges (Weisz et al., 2008; Schlappy et al., 2010).
The sponge choanocyte is considered one of the few examples of a true sieve filter in metazoans (Riisgard and Larsen, 2001).
About 36 h after settlement, choanocytes are differentiated in the inner cell mass and formation of the choanocyte chamber begins.
Male generative cells appear to originate from choanocytes that migrate into the lumen of choanocyte chambers, where spermatogenesis takes place.
A section through the sponge reveals two distinct regions: a cortical zone called ectosome, and an internal zone, the choanosome, which contains the choanocyte chambers.
The choanocytes of Acanthochaetetes wellsi possess a periflagellar sleeve; a central cell at the apopyle of the choanocyte chambers, as in the Hadromerida; and a spicule complement similar to that of the family Spirastrellidae in the order Hadromerida (Hartman and Goreau, 1975; Vacelet and Garrone, 1985; Reitner and Engeser, 1987; Boury-Esnault et al., 1990).
In the sections of sponge branches we were able to identify the following epithelial cells: exopinacocytes (covering the outer sponge surface), endopinacocytes (lining the water canals), and choanocytes (lining choanocyte chambers in the canal system).
Sometime later, a canal system and choanocyte chambers are formed in the metamorphs.
In addition, the absence of a periflagellar sleeve from around the base of the choanocyte's flagellum, which is typical of hadromerid sponges (Vos et al., 1991), also strengthens this view.