Kentrosphaera Borzì, 1883

Lectotype species: Kentrosphaera facciolaae Borzì

Currently accepted name for the type species: Scotinosphaera paradoxa Klebs

Original publication: Borzì, A. (1883). Studi algologici. Saggio di richerche sulla biologia delle Alghe. Fascicolo I. pp. [i]-vi, [i, h.t.], [i]-i 117, [i, cont.], errata slip, IX pls., uncol. liths. by author. Messina: Gaetano Capra e Co. Editori.

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Type designated in: Fott, B. (1975). Übersicht der Familie der Characiaceae (Chlorococcales) mit taxonomischen Namensänderungen und Neubeschreibungen. Preslia 47: 211-231.

Description: Thalli unicellular, mostly free-living, rarely endophytic in some aquatic plants. Cells solitary, occasionally clustered, considerably variable in shape (globose, ellipsoidal, pyriform, bean- or club-shaped to irregularly lobed), 5-200 (-370) &m in diameter or length. Cell walls initially thin, homogeneous and colorless, becoming irregularly thick, stratified and yellowish or brownish with age; often with one to several local thickenings that may develop into extensive protrusions. Cells uninucleate, nuclei increasing in size with cell volume. Chloroplast primarily parietal consisting of one to several plate-like segments with 1 or 2 pyrenoids; later axial, very massive, with numerous strands running from peripheral plates to one to several pyrenoids. Pyrenoids covered with starch grains. Asexual reproduction by zoospores and autospores. Sporogenesis initiated with accumulation of secondary carotenoids in peripheral cytoplasm and proceeding with multiple bipartitions of chloroplast prior to karyokinesis; cytokinesis more or less simultaneous. In one sporangium spores often differing in size and shape. Zoospores biflagellate, naked, produced mostly 64-250 (-500) per sporangium; released via mucilaginous vesicle. Autospores thin walled, 16-128 per sporangium; released by rupture of sporangial wall. Resting cells with thick (to 35 &m), wrinkled and highly stratified cell wall, and olive green to orange protoplast filled with storage materials (starch, oil) and fragmented chloroplast. Sexual reproduction unknown. Kentrosphaera mostly free-living, sometimes growing in mucilage of cyanobacteria and algae or endophytic in aquatic plants (e.g., Lemna); in freshwater in natural, stagnant water and artificial reservoirs, and on damp soil or wet stones; reported from Europe, North America and Antarctica. Genus considered close to Chlorochytrium, original distinguishing features based on differences in modes of reproduction and host relationships. Both criteria found to be unreliable and insufficient for distinguishing genera and they were synonymized by some authors. Recent studies distinguish genera based on sporogenesis. Additional diagnostic features relating to cell dimensions and chloroplast morphology require further study. Species of Kentrosphaera distinguished based primarily on chloroplast morphology and number and arrangement of pyrenoids in adult cells.

Information kindly contributed by M. Puncochárová but may now be outdated.

Taxonomic status: This name is currently regarded as a synonym of Scotinosphaera.

Most recent taxonomic treatment adopted: Tsarenko, P.M. (2011). Chlorococcales. In: Algae of Ukraine: diversity, nomenclature, taxonomy, ecology and geography. Volume 3: Chlorophyta. (Tsarenko, P.M., Wasser, S.P. & Nevo, E. Eds), pp. 232-264. Ruggell: A.R.A. Gantner Verlag K.-G..

Comments: Wujek & Thompson (2005) consider Scotinosphaera and Kentrosphaera to be synonymous, with the former name having priority.

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Contributors
Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in CD format. These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above. The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.

Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.

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Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 02 May 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 19 April 2024