Cocconeis magnoareolata Al-Handal, Riaux-Gob., R.Jahn & A.K.Wulff, 2019
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publication ID |
https://doi.org/ 10.5852/ejt.2019.497 |
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persistent identifier |
https://treatment.plazi.org/id/E8593F00-FFB6-FFBB-FEAE-FD998EEEFE3C |
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treatment provided by |
Plazi |
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scientific name |
Cocconeis magnoareolata Al-Handal, Riaux-Gob., R.Jahn & A.K.Wulff |
| status |
sp. nov. |
Cocconeis magnoareolata Al-Handal, Riaux-Gob., R.Jahn & A.K.Wulff sp. nov. Figs 2–7 View Figs 2–9 , 16–27 View Figs 16–21 View Figs 22–27
Differential diagnosis (LM)
Valves elliptic to broadly elliptic with rounded apices. Apical axis 6–8.5 µm (7 ± 0.8), transapical axis 4.5–6 µm (4.8 ± 0.5, n = 60). Raphe filiform and straight, axial area very narrow, RV central area very small. Striae coarse on both valves, weakly radiate to parallel at the middle and strongly radiate near the apices, 21–22 in 10 µm on both valves. Areolae subquadrangular, coarse and distinct, 4–5 in each stria at the middle of the valve.
Etymology
The epithet given to the species refers to the large shape of the areolae on both valves.
Type material
Holotype ( Figs 2, 6 View Figs 2–9 : http://phycobank.org/1000794) 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 43104 . View Materials GoogleMaps
Isotype SWEDEN • Same data as for the holotype; Department of Biological and Environmental Sciences, University of Gothenburg, slide V001 .
Description (SEM)
Sternum valve
Externally, flat to weakly convex with short mantle ( Figs 17–18 View Figs 16–21 ). Axial area narrow and straight, reaching valve apices ( Fig. 17 View Figs 16–21 ). Striae uniseriate, reaching valve margin, weakly radiate at the middle and curved on apices. Areolae large, subquandragular with round corners, becoming slightly oblong on the apices ( Figs 17–18 View Figs 16–21 ). Areolae occluded by reticular hymenes with short slits arranged on the margin of the areolae ( Fig. 19 View Figs 16–21 , arrow). Internally, virgae strongly silicified and more prominent than on the external face, sternum relatively large and straight, ending by a triangular hyaline area on apices ( Fig. 16 View Figs 16–21 ). Areolae more oblong than on the external side but the last areolae near valve margin are round ( Fig. 16 View Figs 16–21 ). SV valvocopula open, fimbriae short and triangle-like ( Figs 20–21 View Figs 16–21 ).
Raphe valve
Externally, valve face flat with a shallow mantle ( Figs 25–26 View Figs 22–27 ). Raphe straight, filiform, proximal raphe endings indistinct ( Figs 22, 26 View Figs 22–27 ), terminal raphe fissures round and slightly widening, helictoglossae very low. Axial area very narrow, central area small and round. Striae uniseriate, weakly radiate at the middle and curved on apices. Areolae coarse, increase in size from the axial area towards valve margin, occluded by hymenes with short slits arranged on areolae margins ( Fig. 27 View Figs 22–27 , arrow). Internally, valve face flat with silicified narrow rim running below the valve margin and following curvature of valve
outline, and encompassing a single longitudinal row of areolae ( Figs 23, 25 View Figs 22–27 ). Proximal raphe endings deflected in opposite directions, terminal raphe fissures ending in slightly raised and short helictoglossae ( Fig. 23 View Figs 22–27 ). Axial area very narrow, central area small, round, slightly elevated above valve face. Areolae orbicular or with irregular shape, increasing in size near the valve margin. Areolae near the valve margin are large and round. Valvocopulae not observed.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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