Irena Kaczmarska, Regine Jahn
Taxonomic appraisal of Melosira arctica Dickie and description of a new variety (Bacillariophyta)
Original material of Melosira arctica was examined. Species circumscription is emended to include detailed frustule fine structure and, for the first time, the basic morphometrics of the population from original material have been established using light and electron microscopy. This original population, collected in 1850, was compared to three contemporary populations of this taxon, collected at Arctic Ocean stations ranging from latitude of 71° to 76° N and from longitude 77° to 173° W. As a result of morphometric examination, a new variety, M. arctica var. krembsii, is proposed. The new variety differs from the nominate variety by finer perforation of the valvocopulae, by fewer marginal rimoportulae in 10 ?m located further above the mantle margin, by fewer rimoportulae on the valve face, and by finer striation of the valves. Based on published illustrations, we suggest that M. arctica var. krembsii may be more common at latitudes south of 70° N, while the nominate variety occurs in more polar seas.
Botanica Marina, Walter de Gruyter
Print ISSN: 0006-8055
Volume: 49, 04/2006
Pages: 151 - 164
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