Pycnococcus Guillard, 1991
Holotype species: Pycnococcus provasolii Guillard
Currently accepted name for the type species: Pseudoscourfieldia marina (Throndsen) Manton
Original publication and holotype designation: Guillard, R.R.L., Keller, M.D., Okelly, C.J. & Floyd, G.L. (1991). Pycnococcus provasolii gen. et sp. nov., a coccoid prasinoxanthin-containing phytoplankter from the western north Atlantic and Gulf of Mexico. Journal of Phycology 27(1): 39-47.
Request PDFDescription: Unicellular picoplanktonic green cells surrounded by thin wall-like structure. Cells contain a single parietal chloroplast with one or two pyrenoids invaginated by channels from the mitochondrion. Flagella lacking. A single operculum-like region present in the wall. Cells spherical, 1.5-4 _m in diameter. A flagellate stage also known, but details of the flagellar apparatus are lacking. In swimming cells the single emergent flagellum emerges anteriorly but folds back along the cell and is directed backwards. Cell division apparently by fission. Sexual reproduction unknown. This tiny unicell is presently known from the western North Atlantic and the Gulf of Mexico. In pigmentation it shows resemblance to the primitive prasinophytes and was therefore included in this class as a separate family. The very unusual pyrenoid structure, with an invagination from the mitochondrion has a parallel in the scaly prasinophyte Pseudoscourfieldia. Unicellular picoplanktonic green cells surrounded by thin wall-like structure. Cells contain a single parietal chloroplast with one or two pyrenoids invaginated by channels from the mitochondrion. Flagella lacking. A single operculum-like region present in the wall. Cells spherical, 1.5-4 _m in diameter. A flagellate stage also known, but details of the flagellar apparatus are lacking. In swimming cells the single emergent flagellum emerges anteriorly but folds back along the cell and is directed backwards. Cell division apparently by fission. Sexual reproduction unknown. This tiny unicell is presently known from the western North Atlantic and the Gulf of Mexico. In pigmentation it shows resemblance to the primitive prasinophytes and was therefore included in this class as a separate family. The very unusual pyrenoid structure, with an invagination from the mitochondrion has a parallel in the scaly prasinophyte Pseudoscourfieldia.
Information kindly contributed by Ø. Moestrup but may now be outdated.
Taxonomic status: This name is currently regarded as a synonym of Pseudoscourfieldia.
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.
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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=44987
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 18 October 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 02 December 2024
