153,593 species and infraspecific names are in the database, 20,980 images, 59,399 bibliographic items, 411,125 distributional records.

Synarthrophyton R.A.Townsend, 1979

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Biliphyta
Phylum Rhodophyta
Subphylum Eurhodophytina
Class Florideophyceae
Subclass Corallinophycidae
Order Hapalidiales
Family Hapalidiaceae
Subfamily Melobesioideae

Holotype species: Synarthrophyton patena (J.D.Hooker & 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.

Precise date of publication29 August 1979 (stated on front cover of journal issue) The requirements for valid publication are specified in the ICBN (International Code of Botanical Nomenclature).

Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Schneider, C.W. & Wynne, M.J. (2007). A synoptic review of the classification of red algal genera a half a century after Kylin's "Die Gattungen der Rhodophyceen". Botanica Marina 50: 197-249.

Nomenclatural notes
The ICBN rules cited below are those adopted by the Seventeenth International Botanical Congress, Vienna, Austria, July 2005 (McNeill et al. 2006).

In accordance with ICBN Art 13.3, the name Synarthrophyton Townsendis is treated as pertaining to a non-fossil taxon because its type is based on a non-fossil specimen. No species based on fossil types have been assigned to the genus to date.

The generic name Synarthrophyton is typified (ICBN Art. 10.1) by the type of S. patena, the only species originally included in the genus. - (20 Jul 2009) -

The family name Mesophyllaceae, introduced by Athanasaidis (2016: 212) is an illegitimate later homonym of Mesophyllaceae Heeg (Equisetopsida). - (30 Nov 2017) - M.D. Guiry

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 30 Nov 2017 by M.D. Guiry.

Characters considered diagnostic of Synarthrophyton: Characters collectively considered diagnostic of Synarthrophyton: Synarthrophyton is the only known genus of Hapalidiaceae, Subfamily Melobesioideae with: 1) monomerous thallus construction throughout; 2) epithallial cells with outermost walls rounded or flattened but not flared at the corners; 3); subepithallial initials usually as long as or longer than their immediate inward derivatives; 4) haustoria unknown; 5) spermatangia formed on both branched and unbranched filaments that arise from the conceptacle chamber floor and roof; 6) spermatangial initials overlain by a layer of protective cells during early stages of development; and 7) spermatangial conceptacle roof formation occurring centripetally from groups of vegetative filaments peripheral to the spermatangial filaments.

As noted by Woelkerling & Harvey (1992: 395-397, Table 2), distinctions between Synarthrophyton, Mesophyllum, and Clathromorphum currently are based on differences in spermatangial filaments (branched & unbranched in Synarthrophyton; all unbranched in Mesophyllum and Clathromorphum); the occurrence of protective cells associated with young spermatangial initials (present in Synarthrophyton and Mesophyllum; unknown in Clathromorphum), and spermatangial conceptacle roof development (centripetal from groups of vegetative filaments peripheral to spermatangial filaments in Synarthrophyton and Mesophyllum; but vertical from continued meristematic activity in filaments that form the spermatangial initials in Clathromorphum). These character states have been confirmed to occur in the type species of Synarthrophyton and Mesophyllum, but male conceptacles remain unknown in C. compactum, the type species of Clathromorphum (see Lebednik 1977: 69-71, 107). In addition, the use of spermatangial filament branching to separate Synarthrophyton from Mesophyllum requires further study (see Keats & Chamberlain 1997: 77; Keats & Maneveldt 1997: 465-466; Woelkerling 1996: 201). The assignment of species for which male conceptacles are unknown to any of the above genera therefore appears equivocal. See AlgaeBase entries for Clathromorphum and Mesophyllum for further information on those genera.

Similarly the presence or absence of coaxial growth at best provides limited indication of generic affinity. Species lacking coaxial growth occur in Clathromorphum, Mesophyllum, & Synarthrophyton, while species with at least some coaxial growth occur in both Synarthrophyton and Mesophyllum.

Coaxial growth, once considered diagnostic of Mesophyllum, is no longer used in that capacity (e.g. see Woelkerling & Harvey 1992: 395-396; Keats et al. 2000: 397) for non-fossil species, and, indeed, non-fossil species lacking coaxial growth have been assigned to the genus (e.g. Athanasiadis 1999: 240, 244). For fossil taxa, however, coaxial growth still remains in use as a generic character on pragmatic grounds (e.g. see Stockar 2000: 416; Braga 2003: 53-55; Iryu et al. 2009: 412-413) because fossil male conceptacles (see below) have yet to be found. As a result, palaeontologists, in the absence of evidence from male conceptacles, continue to place species with multiporate conceptacles, cell fusions and at least some coaxial growth in Mesophyllum although it is not possible to determine unequivocally whether such species belong to Mesophyllum or Synarthrophyton

Characters considered diagnostic of higher taxonomic ranks known/presumed to occur in all species of Synarthrophyton: Characters considered diagnostic of higher taxonomic ranks and known/presumed to occur in all species of Synarthrophyton: 1) calcification in the form of calcite; 2) pit plugs with two cap layers at cytoplasmic faces, the outer cap dome shaped; membrane absent; 3) cell walls impregnated with calcite; 4) gametangia and carposporangia produced within uniporate conceptacles; 5) tetrasporangia/bisporangia produced within conceptacles and possessing zonately arranged spores; 6) tetrasporangial/bisporangial conceptacles possessing multiporate plates or roofs; 7) tetrasporangia/bisporangia producing apical plugs; 8) tetrasporangial/bisporangial conceptacles with multiporate roofs composed of cells; lacking an acellular multiporate plate recessed below a single outer opening; and 9) cells of contiguous vegetative filaments linked exclusively by cell fusions. Characters 1-2 are considered diagnostic of the Corallinophycidae, 3-5 of the Corallinales, 6-7 of the Hapalidiaceae, and 8-9 of the Melobesioideae.

Generic synonyms: No synonyms of Synarthrophyton Townsend are known

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.

Numbers of names and species: There are 11 species names in the database at present, of which 11 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.

References
Athanasiadis, A. (1999). Mesophyllum macedonis, nov. sp. (Rhodophyta, Corallinales), a putative Tethyan relic in the north Aegean Sea. European Journal of Phycology 34: 239-252, 23 figs, 1 table.

Braga, J.C. (2003). Application of botanical taxonomy to fossil coralline algae (Corallinales, Rhodophyta). Acta Micropalaenotologica Sinica 20: 47-56.

Harvey, A.S., Broadwater, S.T., Woelkerling, W.J. & Mitrovski, P.J. (2003). Choreonema (Corallinales, Rhodophyta): 18S rDNA phylogeny and resurrection of the Hapalidiaceae for the subfamilies Choreonematoideae, Austrolithoideae and Melobesioideae. Journal of Phycology 39: 988-998.

Harvey, A.S., Woelkerling, W.J. & Millar, A.J.K. (2009). The genus Amphiroa (Lithophylloideae, Corallinaceae, Rhodophyta) from the temperate coasts of the Australian continent, including the newly described A. klochkovana. Phycologia 48: 258-290.

Harvey, W.H. (1849). Nereis australis, or algae of the southern ocean: being figures and descriptions of marine plants, collected on the shores of the Cape of Good Hope, the extra-tropical Australian colonies, Tasmania, New Zealand, and the Antarctic regions; deposited in the Herbarium of the Dublin University. [Part 2]. pp. 65-124 [ends abruptly], pls XXVI-L. London: Reeve Brothers.

Keats, D.W. & Maneveldt, G. (1997). Two new melobesioid algae (Corallinales, Rhodophyta), Synarthrophyton robbenense sp. nov. and S. munimentum sp. nov., in South Africa and Namibia. Phycologia 36: 447-467, 54 figs, 1 table.

Keats, D.W. & Maneveldt, G. (1997). Two new melobesioid algae (Corallinales, Rhodophyta), Synarthrophyton robbenense sp. nov. and S. munimentum sp. nov., in South Africa and Namibia. Phycologia 36: 447-467, 54 figs, 1 table.

Keats, D. W., Maneveldt, G. & Chamberlain, Y. M. (2000). Lithothamnion superpositum Foslie: a common crustose red alga (Corallinaceae) in South Africa. Cryptogamie Algologie 21: 381-400.

Kim, J.H., Chung, H., Choi, D.S. & Lee, I.K. (2004). A new melobesioid alga Synarthrophyton chejuensis sp. nov. (Corallinales, Rhodophyta), including comparison with Mesophyllum cystocarpideum. Phycologia 43: 501-520, 62 figs, 2 tables.

Lebednik, P.A. (1977). Postfertilization development in Clathromorphum, Melobesia and Mesophyllum with comments on the evolution of the Corallinaceae and the Cryptonemiales (Rhodophyta). Phycologia 16: 379-406.

Le Gall, L., Payri, C.E., Bittner, C.E., & Saunders, G.W. (2010). Multigene polygenetic analyses support recognition of the Sporolithales, ord. nov. Molecular Phylogenetics and Evolution 54(1): 302-305.

Le Gall, L. & Saunders, G.W. (2007). A nuclear phylogeny of the Florideophyceae (Rhodophyta) inferred from combined EF2, small subunit and large subunit ribosomal DNA: establishing the new red algal subclass Corallinophycidae. Molecular Phylogenetics and Evolution 43: 1118-1130.

Maneveldt, G. W., Keats, D. W. & Chamberlain, Y. M. (2007). Synarthrophyton papillatum sp. nov.: a new species of non-geniculate coralline algae (Rhodophyta, Corallinales, Hapalidiaceae) from South Africa and Namibia. South African Journal of Botany 73: 570-582.

May, D.I. & Woelkerling, W.J. (1988). Studies on the genus Synarthrophyton (Corallinaceae, Rhodophyta) and its type species, S. patena (J.D. Hooker et W.H. Harvey) Townsend. Phycologia 27: 50-71, 40 figs, 3 tables.

McNeill, J., Barrie, F.R., Burdet, H.M., Demouline, V., Hawksworth, D.L., Marhold, K., Nicolson, D.H., Prado, J., Silva, P.C., Skog, J.E., Wiersema, J.H. & Turland, N.J. (2006). International Code of Botanical Nomenclature (Vienna Code) adopted by the Seventeenth International Botancial Congress Vienna, Austria, July 2005. pp. [i-iv], v-xviii + 1-568. Liechtenstein: A.R.G. Gantner Verlag.

Stockar, R. (2000). Fossil coralline algae from the Paleocene Montorfano Member type-section (Tabiago Formation, northern Italy). Eclogae Geologicae Helvetiae 93: 409-427.

Theriot, E. (1988). A review of Sluiman's cladistic classification of green plants with particular reference to flagellar data and to land plant origins. Taxon 37: 913-919.

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.

Woelkerling, W.J. (1988). The Coralline Red Algae: an analysis of the genera and subfamilies of nongeniculate Corallinaceae. pp. i-xi, 1-268, 259 figs, tables numbered by chapter. London & Oxford: British Museum (Natural History) & Oxford University Press.

Woelkerling, W. J. (1996). Subfamily Melobesioideae. In: The Marine Benthic Flora of Southern Australia - Part IIIB. Gracilariales, Rhodymeniales, Corallinales and Bonnemaisoniales. (Womersley, H.B.S. Eds), pp. 164-210. Canberra: Australian Biological Resources Study.

Woelkerling, W.J. & Harvey, A. (1992). Mesophyllum incisum (Corallinaceae, Rhodophyta) in Southern Australia - implications for generic and specific delimitation in the Melobesioideae. British Phycological Journal 27: 381-399.

Woelkerling, W.J., Irvine, L.M. & Harvey, A.S. (1993). Growth-forms in non-geniculate coralline red algae (Corallinales, Rhodophyta). Australian Systematic Botany 6: 277-293.

Woelkerling, W.J., Millar, A.J.K., Harvey, A. & Baba, M. (2008). Recognition of Pachyarthron and Bossiella as distinct genera in the Corallinaceae, subfamily Corallinoideae (Corallinales, Rhodophyta). Phycologia 47: 265-293.

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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.

Created: 28 December 2000 by M.D. Guiry

Verified by: 30 November 2017 by M.D. Guiry

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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 17 November 2018.

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