Boreolithon A.S.Harvey & Woelkerling, 1995
Holotype species: Boreolithon van-heurckii (Heydrich) A.S.Harvey & Woelkerling
Original publication and holotype designation: Harvey, A.S. & Woelkerling, W.J. (1995). An account of Austrolithon intumescens gen. et. sp. nov. and Boreolithon van-heurckii (Heydrich) gen. et. comb. nov. (Austrolithoideae subfam. nov., Corallinaceae, Rhodophyta). Phycologia 34: 362-382.
Request PDFPrecise date of publication: 25 September 1995
Description: Plants calcified, lacking genicula, entirely pseudoparenchymatous; encrusting in growth-form and epigenous, growing attached to hydroids (the only known substrate); haustoria unknown.
Thallus organization wholly dorsiventral; thallus construction dimerous throughout, composed of two groups of filaments: a ventral-most unistratose layer of filaments (primigenous filaments) from which marginal growth occurs; and epithallial cells (see comments) that arise vertically from cells of ventral filaments; outermost walls of epithallial cells apparently rounded or flattened but not flared at the corners; cell-elongation characteristics uncertain; cells of adjacent filaments apparently not linked by cell fusions or by secondary pit-connections.
Gametangia and carposporangia unknown.
Tetrasporangia unknown. Bisporangia formed in conceptacles. Roofs of bisporangial conceptacles multiporate and composed of cells. Bisporangia each containing two zonately arranged spores and producing an apical plug that blocks a roof pore before spore release.
Information contributed by: Wm. J. Woelkerling. The most recent alteration to this page was made on 2017-01-20 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
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.
Comments: Knowledge of Boreolithon is based on the original account of Harvey & Woelkerling (1995), but because the type and only known species, B. vanheurckii, is based solely on bisporangial plants, the status of Boreolithon as a distinct genus of Austrolithoideae may require further evaluation. B. vanheurckii, was originally described as a species of Lithothamnion; the rather contorted taxonomic history of the species is summarized by Harvey & Woelkerling (1995: 374). Growth-form terminology follows (Woelkerling et al. 1993).
The lectotype of B. vanheurckii has been studied and illustrated most recently by Chamberlain & Irvine (1994: 199-201, figs 95-96, as Melobesia) and by Harvey & Woelkerling (1995: 374-377, figs 42, 46-50), who listed earlier references to the species. Epithallial cells were recorded in the lectotype by Chamberlain & Irvine (1994) and also were reported by Chalon (1905) and Cabioch (1972: 179), but Harvey & Woelkerling (1995) were unable to detect epithallial cells in the lectotype. In addition, Chalon (1905: 208), Heydrich (1905: [2]), Cabioch (1972: 179) and Chamberlain & Irvine (1994: 199, 200) all suggested that the species was not calcified, whereas Harvey & Woelkerling (1995: 376) determined from scanning electron microscopy and x-ray microanalysis that lectotype plants were calcified. Neither cell fusions nor secondary pit-connections have been reported.
Biogeographically, Boreolithon presently is known only from Jersey (Channel Islands, United Kingdom) and northern France (Golfe de St. Malo, Bay of Biscay).
The lists below of diagnostic characters of Boreolithon, and of the higher taxa to which it belongs, are derived from data in Harvey & Woelkerling (1995), 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 Boreolithon from other genera of the Hapalidiaceae, subfamily Austrolithoideae.
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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.
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Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 20 January 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 19 April 2024
