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| Schizymenia jonssonii K.Gunnarsson & J.Brodie in Gunnarsson, Russell & Brodie, 2020. |
Abstract
North-Atlantic records of Schizymenia dubyi extend along the eastern shores of the North Atlantic from Morocco to southern Britain and Ireland, and the species is also recorded from Iceland. A study was undertaken to confirm the identity of the specimens from Iceland that were geographically separate from the main distribution of S. dubyi and in contrast to other species of the genus did not have gland cells. We analyzed rbcL and COI molecular sequence data from Icelandic specimens and compared the results with those for Schizymenia specimens available in GenBank. For both markers, Schizymenia was shown to be a monophyletic genus. The Icelandic specimens were clearly genetically distinct from S. dubyi and formed a well-supported clade with Schizymenia species from the Northern Pacific. Based on these results, we have described a new species, Schizymenia jonssonii, which can be distinguished by molecular phylogeny, its lack of gland cells and by being strictly intertidal. Crustose tetrasporophytes with identical COI and rbcL sequences were found at the same locations as foliose plants. Schizymenia apoda is reported for the first time in the UK, its identity confirmed by rbcL sequence data. In light of these findings, it is likely that by further molecular analysis of the genus Schizymenia in the north-eastern Atlantic and the Mediterranean, a higher diversity of Schizymenia spp. will be discovered in this region.
Keywords: COI, Iceland, molecular phylogeny, phenology, North Atlantic, rbcL, Schizymenia jonssonii
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| Holotype specimen of Schizymenia jonssonii sp. nov. (BM013844101), collected at Stekkjarvikur, SW Iceland on April 21, 2016. Scale = 2 cm. |
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| Life history phases of Schizymenia jonssonii sp. nov. growing in the lower intertidal in Stekkjarvikur, SW-Iceland. (a) Blades – gametophyte phase, July 4, 2016. (b) Crusts – tetrasporophyte phase, March 1, 2018. Scale = 2 cm. |
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| Schizymenia jonssonii sp. nov. (a) Transverse section (T.S.) of blade. (b) Cystocarps between the inner cortex and medulla in T.S. of the blade. Ostioles opening to the surface. (c) Zonate tetrasporangia just below the surface of a sporophyte crust. (d) Tetraspores being released. (e) T.S. of a tetrasporophyte with openings between layers. (f) Rhizoids on the underside of the tetrasporophyte. Scale (a–d and f) = 50 μm and (e) = 1 mm. |
Schizymenia jonssonii K.Gunnarsson & J.Brodie sp. nov.
Diagnosis: Gametophytic phase foliose with surface either flattened or with irregular ridges and depressions. Thallus lacking gland cells. Color dark red to brownish red. Tetrasporophytic phase crustose, with uneven surface having numerous small swellings. Can equally be distinguished by its nucleotide sequences of the mitochondrial COI and plastid rbcL genes.
Etymology: The species is named in honor of the Icelandic phycologist Sigurður Jónsson, for his contribution to the knowledge of Icelandic macroalgae and phycology in general.
Karl Gunnarsson, Stephen Russell and Juliet Brodie. 2020. Schizymenia jonssonii sp. nov. (Nemastomatales, Rhodophyta): A Relict or An Introduction into the North Atlantic after the last Glacial Maximum? Journal of Phycology. 56(2); 324-333. DOI: 10.1111/jpy.12957
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A new species of red algae discovered in Iceland
