Ostreobium Bornet & Flahault, 1889

Holotype species: Ostreobium quekettii Bornet & Flahault

Original publication and holotype designation: Bornet, É. & Flahault, C. (1889). Sur quelques plantes vivants dans le test calcaire des mollusques. Bulletin de la Société Botanique de France 36: CXLVII-CLXVII [147-167], pls VI-XII [6-12].

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Description: Plants consisting of endozoic (endolithic) branched siphonous filaments 1-160 _m in diameter. Filaments straight and sparsely branched or forming irregular, tangled networks. Filaments more or less uniform within single thalli or highly variable, forming cylindrical portions and/or with inflated regions. Nuclei numerous. Cytoplasm in one species (O. constrictum) with numerous, colorless (protein?) bodies 4-5 _m diameter. Chloroplasts small, spherical or polyhedral to reticulate; pyrenoids absent. Cell walls thin and undifferentiated to thick and lamellose. Reproduction by quadriflagellate zoospores known only Ostreobium quekettii. Sporangia irregularly lobed and forming one to several exit tubes. Ostreobiummarine, widely distributed in tropical to temperate areas, growing primarily in calcified substrata including corals, calcified red algae and old mollusk shells; recently reported from the tunics of ascidians. Ostreobium is among the deepest growing macroalgae in both temperate and tropical regions. Species differences based on the presence or absence of differentiated filaments, presence of septa, and filament diameter. Distinctions among several described species are questionable. Most studies refer to O. quekettii or to Ostreobium sp. Variation in single plants can cross several apparent species boundaries. Extensive physiological studies on in situ photosynthesis by Ostreobium confirm low levels of light requirements and an ability to utilize near infra-red light greater than other green algae. A modified photosystem I reaction centre was hypothesized to account for this. Affinities of Ostreobium within Bryopsidales unclear, and family was suggested to comprise its own order. Presence of the pigments siphonein and siphonaxanthin consistent with placement in Bryopsidales. This is the only genus within Bryopsidales known to form quadriflagellate zoospores.

Information contributed by: D. Garbary. The most recent alteration to this page was made on 2016-12-23 by M.D. Guiry.

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

Most recent taxonomic treatment adopted: Sauvage, T., Schmidt, W.E., Suda, S. & Fredericq, S. (2016). A metabarcoding framework for facilitated survey of endolithic phototrophs with tufA. BMC Ecology 16:8: 1-22.

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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=37528

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 23 December 2016. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024