Arthrothamnus, 1848: 67
Holotype species: Arthrothamnus kurilensis Ruprecht
Original publication:Ruprecht, F.J. (1848). Bemerkungen über den bau und das wachstum einiger grossen algen-stamme, und über die mittel, das alter derselben zu bestimmen. Mémoires de l'Académie Impériale des Sciences de Saint-Pétersbourg, Sér. 6, Sciences Naturelles 6: 59-70.
Taxonomic status: currently recognized as a distinct genus.
Description: Life history diplohaplontic with alternation of large sporophyte bearing unilocular meiosporangia with paraphyses (sori) and microscopic dioecious and oogamous, heteromorphous gametophytes (for detail, see Laminaria). Haploid chromosome number in A. bifidus is n = 22 (Yabu and Tokida 1963). Sporophyte perennial, composed of holdfast, stipe and blade. Blade formation is unique within the Laminariaceae. Blade is linear in shape and produces an auriculate outgrowth on both sides of its base when maturing. Both auriculate outgrowth develop into a new stipe and blade while the old overwintering blade is shed in spring leaving a scar extending from the broadened top of the stipe to the base of each outgrowth. This probably annual blade regeneration pattern results in a ramificated stipe, the number of ramifications being equivalent to the age of the sporophyte. Original holdfast composed of short hapteres. Secondary stipes also produce hapteres along lower margin. Sori on A. bifidus develop in winter on both blade surfaces as irregular longitudinal line in the central portion of the blade. Structure of sporophyte as in Laminaria composed of photosynthetic meristoderm, parenchymatic cortex and central medulla.
Comments: Genus endemic to the northern parts of the Pacific (probably from the Aleutian islands to Hokkaido, Japan; also Kamchatka and Saghalien), growing subtidally.
NCBI Nucleotide Sequences
Numbers of names and species: There are 5 species (and infraspecific) names in the database at present, of which 2 have been flagged as currently accepted taxonomically.
Names: ('C' indicates a name that is currently 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):
Arthrothamnus bifidus (S.G.Gmelin) J.Agardh C
Arthrothamnus bongardianus (Postels & Ruprecht) J.Agardh S
Arthrothamnus kurilensis Ruprecht C - type
Arthrothamnus longipes (Bory) J.Agardh P
Arthrothamnus radicans Ruprecht P
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: http://www.algaebase.org/search/genus/detail/?genus_id=41248
Cite this record as:
Guiry, M.D. & Guiry, G.M. 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 10 December 2013.
Algaebase taxon LSID: urn:lsid:algaebase.org:taxname:7797