Pseudoscourfieldia I.Manton, 1975

Holotype species: Pseudoscourfieldia marina (Throndsen) Manton

Original publication and holotype designation: Manton, I. (1975). Observations on the microanatomy of Scourfieldia marina Throndsen and Scourfieldia caeca (Korsch.) Belcher et Swale. Archiv für Protistenkunde 117: 358-368.

Description: Unicellular flagellates with 2 unequal flagella, held parallel and posteriorly during swimming. Cells are oblong to truncate-ovate, slightly flattened, with a posterior depression, from which the 2 flagella emerge. The cell contains a single, disc-shaped, parietal chloroplast with basal pyrenoid. An eyespot is lacking. The cell is wall-less, but all surfaces are covered by unmineralized scales. The cell body and the flagella covered with an underlayer of square to diamond-shaped scales, on the flagella in 24 longitudinal rows. Additional scales on the flagella include 24 double rows of small rods and 2 opposite rows of equally spaced hair-shaped scales. The underlayer on the cell body is covered by another layer of small scales, probably "double-scales" of arrow-shaped rods with opposite polarity. Sexual reproduction unknown. The single known species is widespread (North Atlantic, Scandinavia, South Africa, Australia) but has been sighted relatively few times. Emended description (Crépeault & al. 2024): Cells display two morphotypes that differ mainly by the presence/absence of flagella and scales. Swimming cells are oblong to truncate-ovate with a posterior depression from which emerge two flagella of unequal lengths. Their cell body is 33.5 µm long, their longer flagellum is 10–23 µm in length and their shorter flagellum is 8-14 µm in length. Flagella are held parallel and posteriorly during swimming. Flagellated cells (cell body and flagella) are entirely covered with an underlay of square to diamond-shaped scales. Scales on the fla- gella include 24 double rows of small rods and two opposite rows of equally spaced hair-shaped scales. Cell body scales are covered by another layer of small scales of arrow-shaped rods with opposite polarity. Cells lacking flagella are spherical with a diameter of 1.5–4 µm, are not covered by scales, and have a wall lacking sporopollelin.

Information contributed by: Ø. Moestrup, emended by Crépeault & al. 2024. The most recent alteration to this page was made on 2024-07-30 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Most recent taxonomic treatment adopted: Crépeault, O., Otis, C., Pombert, J.-F., Turmel, M. & Lemieux, C. (2024). Comparative plastome and mitogenome analyses indicate that the marine prasinophyte green algae Pycnococcus provasolii and Pseudoscourfieldia marina (Pseudoscourfieldiophyceae class nov., Chlorophyta) represent morphotypes of the same species. Journal of Phycology 00(00): [1–7], 2 figures, 1 table.

Comments: Ultrastructure was described in detail by Moestrup and Throndsen (1988)

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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=44986

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 30 July 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 21 November 2024