Titanoderma Nägeli, 1858
Holotype species: Titanoderma pustulatum (J.V.Lamouroux) Nägeli
Original publication and holotype designation: Nägeli, C. (1858). Die Stärkekörner. In: Pflanzenphysiologisce Untersuchungen. (Nägeli, C. & Cramer, C. Eds) Vol. 2, pp. i-x, 1-623. Zürich:
Taxonomic status: currently recognized as a distinct genus.
Gender: This genus name is currently treated as neuter.
Most recent taxonomic treatment adopted: Athanasiadis, A. (2016). Phycologia Europaea Rhodophyta Vol. I. pp. [i]-xxxxviii, 1-762. Thessaloniki: Published and distributed by the author.
Monotypic when introduced. - (20 Jan 2017) - M.D. Guiry
Campbell & Woelkerling (1990: 123) and Womersley (1996: 227) consider Titanoderma Nägeli 1858 to be a heterotypic synonym of Lithophyllum Philippi 1837. However, Irvine and Chamberlain (1994: 89) consider Titanoderma to be a distinct genus. - (13 Mar 2009) - Wendy Guiry
Schneider & Wynne (2007: 203) note that the results of Bailey's (1999) study using a molecular comparison demonstrated that Titanoderma is distinct from Lithophyllum. - (13 Oct 2010) - Wendy Guiry
Description: Thalli comprising crusts, irregularly shaped or crowded with protuberances; dorsiventral and/or radial in organization. Epiphytic, epilithic, or unattached. Epiphytic plants sometimes surrounding host branches. Filaments of one (monomerous) or two (dimerous) orders; first-order filaments (primigenous filaments) growing along substrate or into protuberances; second-order filaments (postigenous filaments) growing at right angles from first-order filaments. First-order filaments often containing stratified elongated cells (palisade cells). Outermost walls of epithallial cells rounded or flattened, not flared. Cells in contiguous filaments frequently joined by secondary pit-connections; cell fusions rare. Trichocytes essentially unknown. Reproductive cells forming within uniporate conceptacles. Tetrasporangia or bisporangia arranged in periphery of conceptacle or scattered over the entire floor; central columella present or absent. Apical sporangial plugs absent. Gametangia poorly known.
Information contributed by: H.W. Joahnsen. The most recent alteration to this page was made on 20 Jan 2017 by M.D. Guiry.
Comments: Titanoderma (usually reported as Dermatolithon) appears to be widespread, but because of nomenclatural confusion the extent of its distribution is not clear. Suneson (1950, as Lithophyllum) reported on the bispore vs. tetraspore situation in Europe. Titanoderma is closest to Lithophyllum in that both genera lack haustoria (unlike Ezo) and are dorsiventrally or radially organized (unlike Tenarea). The long-held practice of citing stratified elongate cells in Titanodermato segregate it from Lithophyllum has been questioned (Woelkerling et al 1985).
Numbers of names and species: There are 29 species names in the database at present, as well as 4 infraspecific names. Of the species names, 7 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.
Bailey, J.C. (1999). Phylogenetic positions of Lithophyllum incrustans and Titanoderma pustulatum (Corallinaceae, Rhodophyta) based on 18S rRNA gene sequence analyses, with a revised classification of the Lithophylloideae. Phycologia 38: 208-216, 2 figs, 4 tables.
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.
Campbell, S.J. & Woelkerling, W.J. (1990). Are Titanoderma and Lithophyllum (Corallinaceae, Rhodophyta) distinct genera?. Phycologia 29: 114-125, 16 figs, 2 tables.
Womersley, H.B.S. (1996). The marine benthic flora of southern Australia - Part IIIB - Gracilariales, Rhodymeniales, Corallinales and Bonnemaisoniales. Vol. 5 pp. 1-392, 160 figs. Canberra & Adelaide: Australian Biological Resources Study & the State Herbarium of South Australia.
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: 28 December 2000 by M.D. Guiry
Verified by: 20 January 2017 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=32990
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 20 April 2019.