Planothidium wetzelectorianum Kopalova, Zidarova & Van de Vijver 2016, sp. nov.

• Main Authors: Kopalová, Kateřina, Zidarova, Ralitsa, Vijver, Bart Van De
• Format: Other/Unknown Material
• Language: unknown
• Published: 2016
• Subjects: Biodiversity; Taxonomy; Chromista; Bacillariophyta; Bacillariophyceae; Achnanthales; Achnanthidiaceae; Planothidium; Planothidium wetzelectorianum; Holo; Monolith; Monolith Lake; Ross Island; Antarc*; Antarctica; James Ross Island
• Online Access: https://zenodo.org/record/3853080; https://doi.org/10.5281/zenodo.3853080

Planothidium wetzelectorianum Kopalová, Zidarova & Van de Vijver sp. nov. Figs 25–57 Etymology The species is named after our dear friends and colleagues Dr. Carlos Wetzel and Prof. Luc Ector [Luxembourg Institute of Science and Technology (LIST)] in recognition of the long and fruitful collaboration we had (and have) with these two excellent diatom scientists. Type Monolith Lake, James Ross Island, Antarctica, sample JRI-011 (63°53′52.3″S 57°57′29.0″W) (leg. L. Nedbalová), coll. date: 1 Feb. 2008 (holo-: slide no. BR–4437; iso-: slide PLP–293, University of Antwerp, Belgium). Description Light microscopy (Figs 25–52) Frustules in girdle view nearly straight to weakly curved (Fig. 25). Valves linear-elliptical becoming elliptical in smaller specimens. Valve margins convex with broadly rounded, never protracted apices. Neither cavum nor sinus present. Valve dimensions (n = 25): length 5.5–10.0 µm, width 2.6–3.2 µm. Raphe valve (Figs 26–38): axial area very narrow. Central area absent or weakly enlarged due to shortening of two central striae. Raphe straight, difficult to see in LM. Proximal raphe endings indistinct, straight. Distal endings not discernible. Transapical striae weakly radiate throughout the entire valve, clearly broader than the virgae, 14–15 in 10 µm. Areolae not discernible. Rapheless valve (Figs 39–52): axial area very narrow, linear. Central area asymmetrically enlarged due to shortening of one central stria, never forming fascia. Striae radiate throughout, more radiate near the apices, as broad as or broader than the virgae, 16–18 in 10 µm. Scanning electron microscopy (Figs 53–57) Raphe valve (Figs 53–55): raphe branches almost straight terminating in indistinct straight pores (Fig. 53). Distal fissures absent (Fig. 54). Raphe terminating immediately beyond the last stria (Fig. 54). Striae composed of 3–5 rows of small, rounded areolae (Figs 53, 54). Near the axial area, each stria composed of usually 4–5 rows of areolae, towards the valve margin only 3 rows of areolae present in the ...