Metagoniolithon Weber-van Bosse, 1904

Lectotype species: Metagoniolithon charoides (J.V.Lamouroux) Weber Bosse

Currently accepted name for the type species: Metagoniolithon radiatum (Lamarck) Ducker

Original publication: Weber-van Bosse, A. (1904). Corallinaea verae of the Malay Archipelago. Siboga-Expeditie Monographie 61: 78-110, Plates XIV-XVI.

Type designated in: Manza, A.V. (1937). The genera of the articulated corallines. Proceedings of the National Academy of Science of the United States of America 23: 44-48.

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Description: Thalli comprising crustose holdfasts bearing branched and articulated fronds. Epilithic and epiphytic holdfasts attached with the aid of haustoria. Fronds of calcified, cylindrical intergenicula separated by uncalcified genicula. Branch apices covered by caps of mucilaginous material; apical meristematic cells below caps separated from one another. Intergenicula of arching tiers of medullary cells of uniform height; surrounded by a photosynthetic cortex and a unistratose layer of epithallial cells. Genicula conspicuous and meristematic, branching dichotomously at branch apices and, except in one variety (M. chara var. dichotomum), subsequently producing secondary branches arranged more or less in whorls; intergenicula not branching. Genicular cells not in tiers. Cells in contiguous filaments often joined by fusions; secondary pit-connections lacking. Epithallial cells in intergenicula wider than tall, those in the genicula taller than wide. Trichocytes usually abundant. Reproductive cells formed within conceptacles on the lateral surfaces of intergenicula. Tetrasporangia initiated in cortical tissue in peripheral ring; cells inside ring (cavity cells) elongating and, eventually, disintegrating to form conceptacle chamber. Procarps forming in coherent patch below cap and disintegrating cortical cells; roof formed by overarching filaments. Each carposporangial conceptacle containing a thin, broad fusion cell producing gonimoblast filaments from its periphery. Spermatangial conceptacles apparently develop in a similar manner, with spermatangia forming on the conceptacle floor in low chambers. Details of spore germination unknown.

Information contributed by: H.W. Johansen. The most recent alteration to this page was made on 2016-07-15 by Wendy Guiry.

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

Most recent taxonomic treatment adopted: Kylin, H. (1956). Die Gattungen der Rhodophyceen. pp. i-xv, 1-673, 458 figs. Lund: C.W.K. Gleerups.

Comments: Metagoniolithon contains three species endemic to western and southern Australia where they are common on rocks, algae, and seagrasses. Holdfasts of M. stelliferum attached to the seagrass Amphibolis via an intermediate host: a species of Fosliella epiphytic on the seagrass. Haustoria of Metagoniolithon extend through the thin Fosliellato directly contact the seagrass epidermal cells. Metagoniolithon, the only genus is the Metagoniolithoideae, shares some important characters with Amphiroa, such as conceptacle development, but differs markedly from that genus in many other characteristics, such as cells being joined by fusions rather than secondary pit-connections.

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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=34584

Citing AlgaeBase
Cite this record as:
Wendy Guiry in Guiry, M.D. & Guiry, G.M. 15 July 2016. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024