Holotype species: Tydemania expeditionis Weber Bosse
Original publication:Weber-van Bosse, A. (1901). Études sur les algues de l'Archipel Malaisien. (III). Annales du Jardin Botanique de Buitenzorg 17: 126-141, pls XVII-XIX.
Taxonomic status: currently recognized as a distinct genus.
Description: Thallus large or minute, and calcified (aragonitic morph), the commoner species (or life form) consisting of a series of almost contiguous glomeruli arising in whorls from a single or branched monosiphonous main axis or stolon composed of a single large siphon. Axis to ca. 400-450 µm diameter. Glomeruli, to 3 cm. or more in diameter, are composed of relatively finer, di- to tetrachotomously branched tapering siphons. Small, monostromatic flabella, ca. 1-1.8 cm. long, of laterally connate dichotomous siphons sometimes replace basal glomeruli. Thalli of other species or morph composed solely of flabellae strung on the monosiphonous axis. Glomeruliferous thallus grows to at least 20 cm. in length, but probably to more than a meter, with growth continuous as in Halimeda and Caulerpa; flabellate form to ca. 5 cm. Fine rhizoidal siphons, produced at intervals along main axis, anchor both types of thalli. It seems likely that the flabellate species is an environmental form of glomeruli-bearing species. Elysia spp., a genus of opisthobranch mollusk graze Tydemania, presumably feeding on its plastids. Similar relationships have been established with other bryopsidalean algae such as Codium and Halimeda. Asexual reproduction is by fragmentation. Sexual reproduction involves holocarpy, i.e. essentially entire contents of siphons are released into gametangia during their formation, with thallus dying thereafter. Gametangia are unspecialized siphons; isogametes, concentrated in siphons of glomeruli, are released in early morning.
Information contributed by: L. Hillis. The most recent alteration to this page was made on 13 Sep 2009 by Stephen Cusack.
Comments: Geographical distribution is Indo-Pacific, and essentially tropical. Glomeruliferous form commonly sprawls over and around coral rock in lagoons of coralgal reefs, where the genus may be the predominant alga of some communities. Although Tydemania has been considered a "deep water" species, its vertical range extends from about -1 m. to at least -65 m., with abundance, at some sites, increasing below about -8 m. In the lagoon of Enewetak Atoll, however, lush patches have been observed at -3 to -5 m., and extensive areas of pinnacles are festooned with it at about -8 m. At Enewetak Tydemania was not found on the outside of the atoll. Nonetheless, there, and probably elsewhere in the Marshall Islands, Tydemania ranks second to Halimeda as a carbonate producer. Flabellate forms develop as flattish caespitose patches; their known distribution is from sea level to -40m
Numbers of names and species: There are 3 species names in the database at present, of which 2 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..
Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):
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Verification of data
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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.
Created: 28 December 2000 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=41060
Please cite this record as:
Guiry, M.D. & Guiry, G.M. 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 20 April 2021.