Cocconeis vrangoensis Al-Handal & Riaux-Gob. 2019, sp. nov.
Creators: name: Al-Handal, Adil Y.
name: Riaux-Gobin, Catherine
name: Jahn, Regine
name: Wulff, Angela Katarina
name: Minerovic, Alison
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Chromista
Bacillariophyta
Bacillariophyceae
Achnanthales
Cocconeidaceae
Cocconeis
Cocconeis vrangoensis

description: Cocconeis vrangoensis Al-Handal & Riaux-Gob. sp. nov.
Figs 10–15, 28–45
Differential diagnosis (LM)
Valves broadly elliptic to slightly rhombic, with round apices. Apical axis 13–16 µm (13.9 ± 2.6), transapical axis 12–14 µm (12.9 ± 0.6, n = 72). Raphe straight, ending slightly before apices. Striae parallel in the middle, becoming radiate towards the apices, 24–26 in 10 µm in the RV and 14–16 in 10 µm in the SV. RV with a silica ridge close to the valve margin and following the curvature of the valve, wider near the center and narrower towards the apices.
Etymology
The specific epithet of the new species refers to the location where it was collected.
Type material
Holotype (Figs 11, 13: http://phycobank.org/1000795) SWEDEN • Vrångö Island, eastern side of Vrångö Island; 57°34´N, 11°47´E; Aug. 2016; A. Al-Handal s.n. leg.; intertidal zone, as epiphytic on Ulva intestinalis; BGBM, slide B 40 0 0 43105.
Isotype SWEDEN • Same data as for holotype; Department of Biological and Environmental Sciences, University of Gothenburg, slide V002.
Description (SEM)
Sternum valve
Convex on the external side, valve face flat to slightly depressed, with a wide mantle (Fig. 30). Axial area narrow and plain with no central area and terminating before the mantle (Fig. 30). Striae monoseriate becoming tri- to tetraseriate on the mantle. Virgae narrower than the striae and strongly raised on the internal valve face (Fig. 29). Areolae round to sub- quadrangular on both sides (Figs 29–30), sometime the septum between two adjacent areolae become very low or disappear and the areolae appear oblong with round corners (Figs 28–29). In SV internal side, the areolae are complex structure formed of 5–7 chambers (hymenate openings), one in the center and the others surrounding the central one (Fig. 32). The areolae on the mantle are long and composed of several small openings (Fig. 31). Each of these chambers is occluded by hymenes with linear perforations radially arranged (Figs 32–33). Valvocopula closed (Fig. 36), fimbriae thin, with finger-like extensions. On the advalvar side of the valvocopula, basal parts of the fimbriae are depressed and form grooves below the outer edge of the valvocopula (Fig. 35).
Raphe valve
Externally, RV slightly concave with marginal part of the mantle hyaline and void of areolae (Figs 37– 45, arrow). Raphe straight, proximal raphe endings simple and close to each other, terminal raphe endings slightly widening and terminate shortly before apices (Figs 37–45). Axial area very narrow, central area round and small. RV striae uniseriate except on the mantle where they become biseriate. Areolae round and occluded by hymenes with thin perforations radially arranged (Fig. 43). Internally, the RV face is slightly convex with very narrow hyaline area on the inner side of the mantle which is strongly raised (Figs 40–42). Mantle margin folded inwards with a hyaline area void of areolae (Fig. 41, arrow). Raphe straight, proximal raphe endings deflected in opposite directions, terminal raphe endings terminating shortly before the apices and with weakly developed helictoglossae (Figs 40–42). Axial area very narrow, central area small, strongly silicified, round and raised above valve surface (Figs 40–42). Valvocopula with long and thin fimbriae ending by a hammer-like structure with an oblong papilla (Fig. 45, arrow). Between each pair of well-developed fimbriae there are short extensions that may be vestigial fimbriae (Fig. 44, arrow).
description: Published as part of Al-Handal, Adil Y., Riaux-Gobin, Catherine, Jahn, Regine, Wulff, Angela Katarina & Minerovic, Alison, 2019, Two new marine species of Cocconeis (Bacillariophyceae) from the west coast of Sweden, pp. 1-16 in European Journal of Taxonomy 497 on page 9, DOI: 10.5852/ejt.2019.497, http://zenodo.org/record/2651618