Isotype of this species is deposited in the Croatian National Diatom Collection as permanent slide under accession number HRNDC000008.
This species is named in honour of Prof. Anđelka Plenković-Moraj, leading professor in freshwater ecology at the University of Zagreb, Faculty of Science, Department of Biology.
CROATIA: Crveno jezero Lake, E side coast, sediment at -20 m depth, collection date: 05.05.2017; leg. B. Jalžić, G. Polić & R. Ozimec; coordinates 38.959390N 095.265483W (Accession No. MKNDC 0011245). Slide MKNDC 0011245/A (holotype). Slide BRM Zu 10/97 (isotype). Slide HRNDC 000008 (isotype).
Valves are narrowly clavate to linear and slightly heteropolar in larger specimens to clavate in smaller specimens. Longer specimens have undulated valve margin and an inflated central part, smaller valves are with convex margins. Headpole rounded, non-protracted, slightly narrower than mid-valve, footpole acutely rounded. Widest part in larger specimens is near the mid-valve, smaller specimens are widest in the upper valve half. Valves are 12–45 μm long and 3.0–6.5 μm wide. Axial area in larger specimens is rather wide, lanceolate, widening towards central area; in smaller specimens rather narrow, slightly widened near the central area. Central area wide, clearly separated from axial area. Raphe is clearly visible, straight with small, indistinct proximal endings. Internally, the proximal raphe endings are T-shaped. Distal raphe endings externally are very short, straight, slightly expanded into drop-like pores and not passing on the valve mantle, while internally terminating with distinct helictoglossae. Transapical striae weakly radiate, becoming almost parallel towards poles, 19–22 striae in 10 μm. Striae terminate at the edge of the valve face, and do not extend onto the mantle. Each stria is composed of a single areola. Externally, areolae in the mid-valve have round shape, while towards poles become slightly elongated slits. Internally, areolae appear longer than externally and are covered by fine hymenate occlusions. Two types of striae on the valve mantle were observed. In some specimens striae are composed of few (2-4) round areolae, while in other specimens mantle striae are composed of a single areola with slit-like opening. Girdle composed of several open bands, each bearing a single row of round pores. At footpole, septa, pseudosepta and apical pore field are absent.
Gligora Udovič, Marija; Žutinić, Petar; Kavre Piltaver, Ivna; Kulaš, Antonija; Ozimec, Roman; Tofilovska, Slavica (2018): Gomphosphenia plenkoviciae sp. nov. A new species from Crveno jezero, Croatia // Phytotaxa, 351; 229-238 doi:10.11646/phytotaxa.351.3.4