Isotype of this species is deposited in the Croatian National Diatom Collection as permanent slide under accession number HRNDC000005.
The species has been named after the Adriatic Sea, the area where the species has been discovered.
Croatia: Adriatic Sea, south–eastern coast (P150, N 42°32ʹ E 17°59ʹ). Plankton sample taken at 100 m depth, collected on March 8, 2016 by M. Mejdandžić. Holotype slide of the strain BIOTAII–49 deposited in The Friedrich Hustedt Diatom Study Centre, Bremerhaven, Germany as BRM ZU10/88. Isotype slides deposited at Macedonian diatom collection, Skopje, Macedonia under accession number 011646 MNDC and at Croatian National Diatom Collection, Zagreb, Croatia under accession number HRNDC000005. GenBank accession numbers for BIOTAII-49 are: MF000606 (18S rRNA), MF000632 (rbcL) and MF000618 (psbC).
Cells delicate with lightly silicified frustules and one multilobed plate plastid, usually torsioned around apical axis in various degrees: 11.3–40.4 μm long, 5.5–17.6 μm wide at constricted central part and 8.2–20.1 μm in widest part. Valves linear–lanceolate with scalpeliform apices, 11.3–40.4 μm long, 4.9–8.0 μm wide at central part. Transition from the elevated keel to the valve body creates an impression of an arcuate line. Virgae are straight, parallel, and simple, extending through whole valve body. Valve striae 40–60 in 10 μm. Keel striae 45–50 in 10 μm. The striae are closed by a hymen with round to elliptical perforations arranged in two parallel lines along the striae edges. 4–5 basal fibulae in 1 μm. Sigmoid raphe with simple and straight central and slightly downward curved terminal endings. Raphe fibulae 40–50 in 10 μm. The cingulum is composed of one valvocopulae and three copulae. Valvocopulae and copulae striae occluded by very lightly silicified hymenes perforated with round to elliptical poroids. Abvalvar interstriae in valvocopula sometimes with bifurcated and curled ends. Striae density in copulae same as in valvocopulae, 50–65 in 10 μm.
Mejdandžić, Maja; Bosak, Sunčica; Nakov, Teofil; Ruck, Elizabeth; Orlić, Sandi; Gligora Udovič, Marija; Peharec Štefanić, Petra; Špoljarić, Igor; Mršić, Gordan; Ljubešić, Zrinka (2018). Morphological diversity and phylogeny of the diatom genus Entomoneis (Bacillariophyta) in marine plankton: six new species from the Adriatic Sea // Journal of Phycology, 54, 2; 275-298. DOI:10.1111/jpy.12622.