Micromonas Manton & Parke, 1960, nom. illeg.
Holotype species: Micromonas pusilla (Butcher) Manton & Parke
Currently accepted name for the type species: Micrinomonas pusilla (R.W.Butcher) Doweld
Original publication and holotype designation: Manton, I. & Parke, M. (1960). Further observations on a small green flagellate with special reference to possible relatives of Chromulina pusilla Butcher. Journal of the Marine Biological Association of the United Kingdom 39: 275-298, 59 figs.
Description: Motile cells ellipsoid to pyriform, slightly compressed, naked (cell wall absent, no organic body scales), 1-3 µm long, 0.7–1 µm broad; one flagellum attached laterally, less than 1 µm long, with a 1-7 µm-long hair point; tiphairs about 1 µm long at the extremity of the hair point; cells without body and flagellar scales, chloroplast single, appearing crescent-shaped in side view with a large pyrenoid filling the concavity; starch shell around the pyrenoid visible underelectron microscopy; stigma absent; one mitochondrion lying on inner face of the chloroplast; no contractile vacuole; nucleus subspherical, situated near the flagellar base; fission in motile or palmelloid phase. First base pair of Helix 11 in the nuclea rencoded small subunit rRNA is C-G instead of U-A.
Information kindly contributed by Slightly modified from emended description by Simon, Foulon & Marin in Simon et al. (2017). but may now be outdated.
Gender: This genus name is currently treated as feminine.
Most recent taxonomic treatment adopted: Simon, N., Foulon, E., Grulois, D., Six, C., Desdevises, Y., Latimier, M., Le Gall, F., Tragin, M., Houdan, A., Derelle, E., Jouenne, F., Marie, D., Le Panse, S., Vaulot, D. & Marin, B. (2017). Revision of the genus Micromonas Manton et Parke (Chlorophyta, Mamiellophyceae), of the type species M. pusilla (Butcher) Manton & Parke and of the species M. commoda van Baren, Bachy and Worden and description of two new species based on the genetic and phenotypic characterization of cultured isolates. Protist 168(5): 612-635, 8 figures, 4 tables.
Comments: One of the smallest known flagellates broadly distributed in estuaries, coastal habitats and open oceans from the poles to the equator.. M. pusilla is distributed in all seas and often occurs in very large numbers. In the Caribbean, Throndsen (1976) found M. pusilla in high numbers not only near the surface but also in ca 100,000 cells per litre at 100 m depth. Under the light microscope it is easily mistaken for a rapidly swimming bacterium. Based on pigment analysis, Micromonas shows affinities with the Mamiellales group of the Prasinophyceae, from which it differs in the lack of scales. It is probably derived from a scale-bearing type like Mantoniella, in which the scales were lost and the flagellum reduced to its present condition, which represents a unique type.
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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=44567
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 24 July 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 04 December 2023