Pyrophacus F.Stein, 1883

Holotype species: Pyrophacus horologium F.Stein

Original publication and holotype designation: Stein, F. (1883). Die naturgeschichte der arthrodelen Flagellaten. In: Der Organismus der Infusionstiere. III. Pt. 2. ( Eds), pp. 1-30. Leipzig:

Description: Unicellular phototrophic, biflagellate heterodynamic cells of various size (30-1190 µm) with cell walls of cellulosic plates. Plate number of episome and hyposome is highly variable, often with broad intercalary bands. Plate formula : Po, 5-8', 9-12", 9-14c, 8s, 9-14"', 1-11p, 3"". The pore plate has a characteristic fishhook-shaped pore. Cells are lenticular in shape, strongly compressed anterio-posteriorly, with equal or subequal altitude of episome and hyposome. In apical and antapical view cells are round with a characteristic concavity at the ventral area. Cingulum is equatorial, deeply impressed, without displacement. Sulcus restricted to the hyposoma, sulcal lists present. Chloroplasts golden-brown, numerous. Vegetative reproduction by binary fission inside the mother cell, daughter cells hatch from the mother cell wall and form a new theca; some authors reported the formation of four daughter cells. Sexual reproduction is anisogamous and heterothallic. Male gametes are smaller and rounder than vegetative cells whereas female gametes cannot be distinguished from vegetative cells. Eight or 16 male gametes are released by one cell. Fusion of the anisogamets occurs during the dark period, the resulting planozygote swims for two to three days before becoming non-motile. The hypnozygote produces the typical dumbbell-shaped cysts in about one week. The cysts have been described as separate cyst genus : Tuberculodinium Wall. These cysts have been found as fossils back to the Pleistocene. Habitat: Marine plankton from tropical to cold-temperate waters in all oceans. Tolerates brackish waters, e.g, in the Baltic Sea.

Information contributed by: M. Elbrächter. The most recent alteration to this page was made on 2021-03-05 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 masculine.

Most recent taxonomic treatment adopted: Tillmann, U., Bantle, A., Krock, B., Elbrächter, M & Gottschling, M. (2021). Recommendations for epitypification of dinophytes exemplified by Lingulodinium polyedra and molecular phylogenetics of the Gonyaulacales based on curated rRNA sequence data. Harmful Algae 103: [1-16], 8 figs, 3 tables.

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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.

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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 05 March 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 24 April 2024

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