Ornithocercus Stein, 1883
Holotype species: Ornithocercus magnificus F.Stein
Original publication and holotype designation: Stein, F. von (1883). Der Organismus der Infusionsthiere nach eigenen forschungen in systematischere Reihenfolge bearbeitet. III. Abtheilung. II. Hälfte die Naturgeschichte der Arthrodelen Flagellaten. pp. 1-30, pls I-XXV. Leipzig: Verlag von Wilhelm Engelmann.
Description: Medium-sized (30-80 µm) laterally compressed flagellate of subcircular, obovate or subtrapeziform in lateral view with characteristic elaborate wings and lists. Very broad cingular lists with many ribs but usually without cross-ribs, in few species with elaborate reticulation between the ribs, separate the reduced epicone from the large hypocone. Right sulcal list usually small, whereas the left sulcal lists are large, extending to the antapex. The small left hypothecal plate bears a list which may extend to the dorsal side of the hypothecal cingular list. These lists have ribs and may have a reticulation. The theca is similar to Dinophysis but apparently has one plate less in the apical region of the ventral apical pore, resulting in only 5 epithecal plates. There are 4 cingular, 4 sulcal, and 4 hypothecal plates as in most other genera of the Dinophysiales. In contrast to Dinophysis, the "ventral" small hypothecal plates are much more elongated, extending to the dorsal side. Nucleus located in the hypocone; chloroplasts absent, food vacuoles present so nutrition is apparently phagotrophic. On the lists and wings, in particular in between the collar-like cingular lists, always present are phaesomes, namely blue-greens of the genus Synechococcus. The exact relationship between these 2 partners is so far unknown. Division is by binary fission in the motile stage, each daughter cell receiving part of the mother theca. Sexual reproduction and cyst formation not known. Marine oceanic plankton, in tropical and subtropical waters of all oceans
Information contributed by: M. Elbrächter. The most recent alteration to this page was made on 2017-05-24 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: Kawai, H. & Nakayama, T. (2015). Introduction (Heterokontobionta p.p.), Cryptophyta, Dinophyta, Haptophyta, Heterokontophyta (except Coscinodiscophyceae, Mediophyceae, Fragilariophyceae, Bacillariophyceae, Phaeophyceae, Eustigmatophyceae), Chlorarachniophyta, Euglenophyta. In: Syllabus of plant families. Adolf Engler's Syllabus der Pflanzenfamilien. Ed. 13. Phototrophic eukaryotic Algae. Glaucocystophyta, Cryptophyta, Dinophyta/Dinozoa, Haptophyta, Heterokontophyta/Ochrophyta, Chlorarachnniophyta/Cercozoa, Chlorophyta, Streptophyta p.p. (Frey, W. Eds), pp. 11-64, 103-139. Stuttgart: Borntraeger Science Publishers.
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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=44663
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 24 May 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 23 March 2023