Syvertsenia iberica (Cymatosiraceae): a new estuarine diatom genus characterized by the position of its process Author Gomes, Ana Centre for Marine and Environmental Research (CIMA), University of Algarve, Campus de Gambelas, 8005 - 139 Faro, Portugal. aisgomes @ ualg. pt Author Witkowski, Andrzej Institute of Marine Sciences, University of Szczecin, Mickiewicza 18, 70 - 383 Szczecin, Poland. Author Dąbek, Przemysław Institute of Marine Sciences, University of Szczecin, Mickiewicza 18, 70 - 383 Szczecin, Poland. Author Boski, Tomasz Centre for Marine and Environmental Research (CIMA), University of Algarve, Campus de Gambelas, 8005 - 139 Faro, Portugal. aisgomes @ ualg. pt Author Moura, Delminda Centre for Marine and Environmental Research (CIMA), University of Algarve, Campus de Gambelas, 8005 - 139 Faro, Portugal. aisgomes @ ualg. pt Author Szkornik, Katie School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire, ST 5 5 BG, United Kingdom. Author Kurzydłowski, Krzysztof Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland text Phytotaxa 2013 2013-11-01 142 1 25 36 http://dx.doi.org/10.11646/phytotaxa.142.1.3 journal article 10.11646/phytotaxa.142.1.3 1179-3163 5099883 Syvertsenia Witkowski & Gomes gen. nov. ( Figs 2–19 ) Cells with one tubular process positioned in the central part of one of the valves mantle ( Figs 3, 4 , Figs 6–8 and Fig. 10 ). Valves linear with rostrate, protracted to distinctly set off, capitate apices. Valve face is flat, the valve mantle relatively steep and in general shallow. In the valve centre (internal view) the mantle bears a convex expansion within which a tubular process and a single adjacent areola are observed ( Figs 10, 12 and 13 ). The distribution of valve face areolae, which are probably closed with cribra, is approximately uniform/equidistant ( Figs 10, 15 ). No fascia, pseudoseptum, pili or apical spines have been observed. TABLE 2. Comparison between the morphological features of the established Cymatosiraceae genera and the new genus proposed (+ = present, - = absent, + / - = present or absent, - / + = usually absent, Inc = incomplete). Adapted from Sabbe et al. (2010) and Hasle et al . (1983).

Taxon	Valve outline	Fascia	Pseudo- septum	Pili	Marginal spines	Process	Apical spines	Other
Cymatosira	Lanceolate to elliptical	-	-	-	+	labiate	+/-	Heterovalvy
Campylosira	Sublunate	-	-	-	+	labiate	+	Heterovalvy
Plagiogrammopsis	Narrowly lanceolate	+	+/-	Inc	+	labiate	+/-	Heterovalvy
Brockmanniella	Narrowly lanceolate, oblong or subcircular with rounded apices	+	-	-	+	labiate	-	Heterovalvy
Minutocellus	Narrowly lanceolate with rostrate apices	-	-	+	-	tubular	+	Heterovalvy
Leyanella	Narrowly lanceolate	-	-	+	-	tubular	-	Heterovalvy
Arcocellulus	Linear oblong	-	-	+	-	tubular	-	Heterovalvy
Papiliocellulus	Narrowly lanceolate to shortly elliptical with subacute apices	-	-	-	-	tubular	-	Heterovalvy
Syvertsenia	Linear with rostrate, protracted to distinctly set of, capitate apices	-	-	-	+	tubular	-	Heterovalvy
Extubocellulus	Broadly lanceolate or subcircular	-	-	-	+/-	tubular, observed very rarely	-	Isovalvy
Pseudoleyanella	Lunate	-	-	-	-	absent	-	Isovalvy
Pierrecomperia	Semi-elliptical to slightly semi-arcuate	-	-	-	+	absent	-	Isovalvy
Cymatosirella	Lanceolate with rounded apices	-	-	-	-	absent	-	Isovalvy

Type species of the genus (designated here): ⎯ S yvertsenia iberica Witkowski & Gomes sp. nov. Etymology: ⎯The genus is named in honor of Dr. Erik E. Syvertsen distinguished Norwegian diatomologist and one of the authors of the family Cymatosiraceae .