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Description
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Punctastriata glubokoensis D.M.Williams, Chudaev & Gololobova emend. Van de Vijver & C.E.Wetzel (Figures 34–84, 108–113) Emended description:––Frustules rectangular in girdle view, solitary or connected to each other by linking spines, forming very short colonies (Figs 34, 67, 108–109). Valves characteristically isopolar, with heteropolar forms representing uncommon exceptions (Fig. 47), elliptic-lanceolate in larger specimens, becoming almost strictly elliptical (Figs 35–84).). Apices broadly rounded in smaller valves (Figs 61–66, 68–84), acutely rounded in larger specimens (Figs 35–60). Apical pore field present on one apex, reduced, composed of only a handful of very small porelli (Fig. 111, white arrow). Valve dimensions (n=40): length 4.5–8.5 (was 4.8-5.7) µm, width 4–5.5 (was 4.1-4.5) µm. Sternum very narrow, lanceolate, zig-zag shape, almost as raised as the virgae (Figs 110–112). Striae weakly radiate throughout the entire cell division circle, 11–13 in 10 µm, stretched ovate in shape, running from mantle to sternum (Fig. 110). Striae composed of 4–5 rows of areolae at valve face-mantle junction, 1–2 rows at the sternum (Fig. 110). Welldeveloped linking spines located on virgae (Figs 108–112). Spine body flattened, solid, with bifurcating tip (Figs 108, 109). Spines usually with a flared, skirt-like projection at the base, sometimes surrounding the entire base of the spine (Fig. 108, white arrows). Abvalvar part of the mantle edge with a broad hyaline zone and small mantle plaques at the mantle edge (Figs 108, 109). Internally, virgae and sternum clearly raised with striae sunken in between (Fig. 113). Cingulum composed of at least a very broad open, unperforated valvocopula and two open copulae (Figs 108, 109, 112). To compare the newly described species with its most similar relative, the morphology of P. lancettula is briefly described based on the original Schumann material from the Koenigsberger Lager in Ost-Preussen, Germany. (2025-11-04)
***This entry has been automatically imported via OpenAlex by LIST harvest scripts. Please refer to https://doi.org/10.5281/zenodo.18416199 for the original and latest version of the publication*** (2026-07-01)
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