Nematochrysopsis Chadefaud, 1947
Holotype species: Nematochrysopsis roscoffensis Chadefaud
Currently accepted name for the type species: Nematochrysopsis marina (J.Feldmann) C.Billard
Original publication and holotype designation: Chadefaud, M. (1947). Une nouvelle Chrysophycée marine filamenteuse: Nematochrysopsis roscoffensis n. g. n. sp. Bulletin de la Société Botanique de France 94: 239-243.
Description: Uniseriate, unbranched filaments, attached by a mucilaginous base of variable length produced by the elongate basal cell. Filaments 8-10 &m in diam. and up to several hundred &m in length; an ecological form with larger filaments (reaching 17 &m in diam.) has been observed (Billard, 1988). Growth of the filaments by intercalary divisions only. Each cell featuring a median constriction prior to division contains four parietal, lobate, yellow-brown chloroplasts with a prominent, bulging pyrenoid. Chrysolaminaran vacuoles and lipid droplets, with numerous muciferous bodies present in older cells. Wall of the cells thick, articulate, with H-shaped pieces, the filaments being externally coated by a thin mucilaginous layer. A single zoospore is formed per cell. Zoospores, negatively phototactic, large, ovate (6-8 ( 10-12 &m), with 2 lateral heterokont flagella (20 and 10-5 &m), inserted in the anterior third of the cell. The anterior flagellum bears tripartite mastigonemes, the posterior flagellum is smooth andacronematic. Cytological characters as in the vegetative cell. No eyespot present. No stomatocysts or sexual reproduction observed in culture. Extracellular calcified pseudocysts, similar to those of Chrysowaernella, have been recorded (Gayral and Lepailleur, 1971). This distinctive marine filamentous organism grows on a variety of substances including artificial ones. Originally described from the Atlantic coast of France (Roscoff), it is most abundant in sublittoral habitats of the Mediterranean and the Adriatic at a depth between 5-40 m where it plays a fundamental role in the formation of seasonal benthic mucilaginous aggregates. Nematochrysopsis morphologically resembles Tribonema, a freshwater genus of the Xanthophyceae, but may be distinguished by ultrastructural and biochemical characteristics (Sartoni and others 1994).
Information contributed by: C. Billard. The most recent alteration to this page was made on 2021-10-08 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as feminine.
Most recent taxonomic treatment adopted: Kristiansen, J. & Preisig, H.R. (2001). Encyclopedia of Chrysophyte genera. Bibliotheca Phycologica 110: 1-260.
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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.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=44776
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 08 October 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 21 November 2024
