Acetabularia J.V., 1812, nom. cons.
Holotype species: Acetabularia acetabulum (Linnaeus) P.C.Silva
Original publication and holotype designation: Lamouroux, [J.V.F.] (1812). Extrait d'un mémoire sur la classification des Polypiers coralligènes non entièrement pierreux. Nouveaux Bulletin des Sciences, par la Société Philomathique de Paris 3: 181-188.
Taxonomic status: currently recognized as a distinct genus.
Most recent taxonomic treatment adopted: Silva, P.C. (1952). A review of nomenclatural conservation in the algae from the point of view of the type method. University of California Publications in Botany 25: 241-323.
Description: Thallus unbranched unicell 1-6 cm long, composed of a compact rhizoid, a tubular stalk ca. 1 mm diam., whorls of thrice-branched sterile laterals and a more or less flattened apical cap 0.5-1.5 cm dia. Whorls periodical from the apex of the stalk and deciduous leaving scars. The mature cap composed of 30-75 free or joined, terminally tapered or rounded elongate rays, which are associated basally with whorls of enlargements, the basipetal inferior corona and the apical superior corona from which project sterile laterals. Thallus lightly to heavily calcified. Thallus size, cap diameter and cap morphology are important species characteristics. Numerous parietal, discoid, grass green plastids without pyrenoids circulate in the peripheral cytoplasm which surrounds a large central vacuole. Chloroplast ultrastructure variable, without or with stacked grana; variable species specific. Starch grains in chloroplast and cytoplasm, the latter not membrane bound. Vegetative cells with a single diploid primary nucleus 75-200 mm dia. located in a branch of the rhizoid. Nucleate and anucleate fragments regenerate normal thalli. Primary nuclear division meiotic followed by a series of mitotic divisions forming secondary nuclei which migrate up the stalk establishing themselves in the rays. Uninucleate aggregations of cytoplasm become thick-walled cysts the nuclei of which further divide and form biflagellate isogametes. Number of cysts per ray variable into the 100's. Gametes 20-50 per cyst . Gametes from heterogenetic cysts fuse after liberation through an ostiole formed by a structured operculum, the cysts liberated from the rays. From zygote germination to gamete liberation takes ca 1 yr. Asexual reproduction by fragmentation, regeneration or development from basal rhizoids. Parthenogenesis of gametes reported in culture but thalli did not form normal apices. Acetabularia pantropical and subtropical. A. calyculus found at 37.5%N and A. mobii at 34%N in Japan. Common in brackish to hypersaline shallow waters. Thalli firmly attached to solid substrates such as stones, coral rubble, shells as well as to wood and industrial detritus such as rubber. Variable seasonal life history especially at the cool extremes of the range. Known from fossil record to Tertiary. The development, nucleo-cytoplasmic interactions, biochemistry, photobiology, genetics and molecular biology of Acetabularia species have been extensively studied. Changes in microtubules and microfilaments associated with key phenomena during growth and differentiation. The taxonomy remains uncertain with some authors accepting the generic segregates Chalmasia and Polyphysa, and others segregating Acetabularia in family Polyphysaceae with Halicoryne or place these genera in a subfamily of Dasycladaceae.
Information contributed by: L.B. Liddle. The most recent alteration to this page was made on 19 Oct 2015 by M.D. Guiry.
German: Schirmchenalge (Braune 2008).
Numbers of names and species: There are 33 species names in the database at present, as well as 6 infraspecific names. Of the species names, 12 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):
Click here to also show infraspecific names in the list below.
Zechman, F.W. (2003). Phylogeny of the Dasycladales (Chlorophyta, Ulvophyceae) based on analyses of RUBISCO large subunit (rbcL) gene sequences. Journal of Phycology 39: 819-827.
Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
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: 29 December 2000 by M.D. Guiry
Verified by: 19 October 2015 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=32940
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 10 December 2018.