Synarthrophyton R.A.Townsend, 1979
Holotype species: Synarthrophyton patena (Hooker f. & Harvey) R.A.Townsend
Original publication and holotype designation: Townsend, R.A. (1979). Synarthrophyton, a new genus of Corallinaceae (Cryptonemiales, Rhodophyta) from the southern hemisphere. Journal of Phycology 15: 251-259, 18 figs, 1 table.
Request PDFPrecise date of publication: 29 August 1979 (stated on front cover of journal issue) The requirements for valid publication are specified in the ICBN (International Code of Botanical Nomenclature).
Description: Plants calcified, lacking genicula, entirely pseudoparenchymatous; encrusting to warty, fruticose, discoid, layered or foliose; epigenous and growing partially to completely attached to the surface of various substrates (e.g. algae, sponges, rock); unattached free-living rhodoliths not recorded; haustoria unknown.
Thallus organization generally dorsiventral in crustose portions but more or less radial in branches; thallus construction monomerous throughout, consisting of a single system of branched laterally coherent filaments that contribute to a ventral or central core and a peripheral region where portions of core filaments or their derivatives curve outwards towards the thallus surface; coaxial growth (in which cells of adjacent filaments in core region are aligned in arching tiers) sometimes present in patches in some species. Most filaments terminating at the upper thallus surface in epithallial cells (generally one per filament); outermost walls of epithallial cells rounded or flattened but not flared at the corners; cell elongation occurring mainly within actively dividing subepithallial initials that are usually as long as or longer than their immediate inward derivatives. Cells of adjacent filaments linked by fusions; secondary pit-connections unknown.
Gametangia (where known) and carposporangia (where known) developing in uniporate conceptacles. Spermatangia (male gametangia) and carpogonia (female gametangia) produced in separate conceptacles or rarely in the same conceptacle; male and female conceptacles formed on the same or on different plants. Spermatangia (where known) formed both on branched and unbranched filaments that arise from the conceptacle chamber floor and roof; spermatangial initials (where known) at first each overlain by a ‘protective cell’ that soon degenerates; spermatangial conceptacle roof formation (where known) occurring centripetally from groups of vegetative filaments peripheral to developing spermatangial filaments on the conceptacle chamber floor. Carpogoina (where known) terminating 2-4 celled unbranched filaments that arise from the conceptacle chamber floor. Carposporophytes (where known) developing in carpogonial conceptacles after presumed fertilization; mature carposporophytes apparently lacking a large conspicuous central fusion cell but composed of an irregularly shaped fusion cell or a several-celled fusion-cell-complex (not always evident) and possessing several-celled filaments bearing terminal carposporangia.
Tetrasporangia/bisporangia formed in conceptacles on separate plants from gametangia and carposporangia. Roofs of tetrasporangial/bisporangial conceptacles multiporate and composed of cells. Tetrasporangia each containing four zonately arranged spores and producing an apical plug that blocks a roof pore before spore release. Bisporangia each containing two spores but otherwise similar to tetrasporangia.
Information contributed by: Wm. J. Woelkerling. The most recent alteration to this page was made on 2024-02-23 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as feminine.
Most recent taxonomic treatment adopted: Athanasiadis, A. & Ballantine, D.L. (2024). Anatomy and classification of the Mesophyllaceae (Corallinales, Rhodophyta), based on phylogenetic principles. Smithsonian Contributions to Botany 118: [i]-xii, [1]-216, 83 figures, 6 tables.
Comments: Information on the taxonomic history, nomenclature, and other matters associated with the name Synarthrophyton is contained in Woelkerling (1988: 210-215). Growth form terminology (encrusting, lumpy, fruticose, etc.) follows Woelkerling et al. (1993).
Data on the lectotype specimen of S. patena (J.D. Hooker & W.H. Harvey in W.H. Harvey) Townsend, the type species of Synarthrophyton, is provided in May & Woelkerling (1988). Most currently recognized species of Synarthrophyton have been the subject of detailed studies (see references in AlgaeBase species accounts), and Maneveldt et al. (2007) provide a comparison of all species recognized up to that date.
Biogeographically, Synarthrophyton is recorded mainly from temperate and colder waters in the southern hemisphere, with one species (S. chejuensis –see Kim et al. 2004) recorded from Korea and Japan. The greatest species biodiversity appears to occur in southern African waters.
The lists below of diagnostic characters of Synarthrophyton, and of the higher taxa to which it belongs, are derived from data in Harvey, Broadwater, Woelkerling & Mitrovski (2003), Harvey, Woelkerling & Millar (2003), Le Gall & Saunders (2007), Woelkerling et al. (2008: 282) and/or Le Gall et al. (2009). Diagnostic characters are those that taken together distinguish a taxon from others of the same taxonomic rank (e.g. characters distinguishing Synarthrophyton from other genera of the Hapalidiaceae, subfamily Melobesioideae). Harvey, Woelkerling & Millar (2003: 653) also provide a diagnostic comparison of Synarthrophyton with other currently recognized non-fossil genera of Melobesioideae.
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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=39500
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 23 February 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024
