Staurosirella marginostriata Van de Vijver & V. Peeters, 2024

Van de Vijver, Bart, Peeters, Valérie, Hansen, Iris, Ballings, Petra & de Haan, Myriam, 2024, Five new species in the genus Staurosirella (Bacillariophyta) from European freshwater habitats, PhytoKeys 242, pp. 139-160 : 139-160

publication ID	https://doi.org/ 10.3897/phytokeys.242.122458
DOI	https://doi.org/10.5281/zenodo.11404246
persistent identifier	https://treatment.plazi.org/id/6EBB8AF9-6DA2-5E0C-ACC1-02AF71F25D51
treatment provided by	PhytoKeys by Pensoft
scientific name	Staurosirella marginostriata Van de Vijver & V. Peeters
status	sp. nov.

Treatment

Staurosirella marginostriata Van de Vijver & V. Peeters sp. nov.

Fig. 1 View Figure 1

Holotype.

BR- 4840 (Meise Botanic Garden, Belgium). Fig. 1 C View Figure 1 represents the holotype GoogleMaps .

Isotype.

Slide 442 (University of Antwerp, Belgium ).

Registration.

http://phycobank.org/104533.

Type locality.

Bosbeek (Maaseik, Province of Limburg, Belgium), sample APM 21-91 , 51 ° 5.6348 ' N, 5 ° 45.894 ' E, coll. date 25 Jun. 2021, leg. Vlaamse Milieu maatschappij ( VMM) GoogleMaps .

Description.

LM (Fig. 1 A – R View Figure 1 ). Frustules in girdle view rectangular, singular. Chains linking several cells in colonies so far not observed. Valves isopolar, strictly lanceolate with convex margins and weakly protracted, rostrate apices. Smaller valves more rhombic-lanceolate with cuneate apices (Fig. 1 R View Figure 1 ). Valve dimensions (n = 20): length 10–20 µm, width 3.0–4.5 µm. Sternum broad, lanceolate, ghost striae present. Striae short, marginal, 14–15 in 10 µm. Areolae not discernible in LM. SEM (Fig. 1 S – X View Figure 1 ). Valve face surface undulating with distinctly raised virgae extending almost up to the valve middle (Fig. 1 T View Figure 1 ), occasionally almost flat (Fig. 1 V View Figure 1 ). Virgae much broader that the striae. Striae very short, marginal, extending without interruption from the valve face onto the mantle (Fig. 1 S – U, W View Figure 1 ). Large hyaline zone present at the abvalvar mantle edge (Fig. 1 S – U View Figure 1 ), terminating at mantle edge by series of irregularly shaped mantle plaques (Fig. 1 S – U View Figure 1 ). Striae uniseriate, composed of short, slit-like, linear areolae, running parallel to the apical axis (Fig. 1 S – W View Figure 1 ). Vimines narrow, not raised. Marginal spines located on the virgae, irregular in number (1–3), shape and size (Fig. 1 S – W View Figure 1 ). Large apical pore fields present at both apices, usually similar in size and shape (Fig. 1 S, T, V View Figure 1 ), located at the valve face / mantle junction, extending more onto the valve mantle, isolated from neighboring striae. Pore fields composed of usually 4–5 rows of small, rimmed pores (Fig. 1 W View Figure 1 ). Girdle composed of several probably open, plain copulae (Fig. 1 S – U View Figure 1 ). Internally, striae distinctly sunken between the raised virgae and the sternum (Fig. 1 X View Figure 1 ).

Etymology.

The specific epithet marginostriata refers to the short, marginal striae.

Distribution.

At present, only observed in Flanders (type locality) and the Morvan region in France. Confusion with the in LM similarly looking Pseudostaurosira brevistriata (Grunow) D. M. Williams & Round ), may be at the base of the unclear distribution.

Ecology and associated diatom flora.

The type locality has an almost circumneutral pH (6.9–7.3), moderate conductivity (160–200 µS / cm), higher nitrate levels (1.4–3.3 mg / l) and sulphate levels (12–30 mg / l). The sample is dominated by Staurosirella stoksiana Van de Vijver sp. nov. (15 % of all counted valves), Aulacoseira ambigua (Grunow) Simonsen (12.5 %), Pseudostaurosira brevistriata (9.5 %), A. granulata (Grunow) Simonsen (9 %), Navicula cryptocephala Kützing (5 %), and N. lanceolata (C. Agardh) Ehrenberg (4 %), pointing to more meso-eutrophic, alkaline conditions ( Lange-Bertalot et al. 2017).