Lyrella karayevae Nevrova, Witkowski, Kulikovskiy & Lange-Bert., 2013

Nevrova, Elena, Witkowski, Andrzej, Kulikovskiy, Maxim, Lange-Bertalot, Horst & Kociolek, J. Patrick, 2013, A revision of the diatom genus Lyrella Karayeva (Bacillariophyta: Lyrellaceae) from the Black Sea, with descriptions of five new species, Phytotaxa 83 (1), pp. 1-38 : 11-12

Lyrella karayevae Nevrova, Witkowski, Kulikovskiy & Lange-Bert. sp. nov. ( Figs 30–34 , Fig. 35 )

Valvae simillimae quoad lineamenta late elliptica cum apicibus late aliquid cuneatim rotundatis; longitudo 44–77 μ m, latitudo 25–45 μ m; ratio longitudo/latitudo 1.45–1.8. Raphe anguste-lateralis extremis centralibus distincte expansis et deflexis ad latus secundum valvae fissuris terminalibus curte hamatis ad latus idem. Area axialis anguste linearis. Area centralis transapicaliter circiter rectangulata coniunxa cum areis lateralibus semi-lanceolatis non geniculatis, 4–5 (non 7–8) μ m latis ( Figs 30–34 ). Areae laterales aliquid diffuse transapicaliter punctatae in prolongatione striarum (non nudae vel cum paucis punctis vix aspectabilibus irregulariter distributis). Striae transapicales marginales radiantes omnino, 10–11 in 10 μ m. Striae adaxiales ex 2–4 areolis compositae, modice radiantes proximaliter et leviter convergentes prope apices. Areolae circiter 14 in 10 μ m. Aspectus ultramicroscopicus externus vide Fig. 35 . Structurae punctiformes non perforantes areas laterales sed levissime in superficiem impressae.

Lyrella karayevae is very similar to Lyrella hennedyi (W. Sm.) Stickle & D.G. Mann in Round et al. (1990: 672), in terms of the valve outlines which are broadly elliptical with broadly rounded, slightly cuneate ends. Length 44–77 µm, breadth 25–45 µm. Length-to-breadth ratio 1.45–1.8. Raphe narrow-lateral, central ends conspicuously expanded and deflected to the secondary side of the valve, like the short hooked terminal fissures. Axial area narrow and linear throughout. Central area transapically expanded, approximately rectangular, connected with the semi-lanceolate lateral areas that are ca. 4–5 (not 7–8) µm broad, not geniculate in the middle ( Figs 30–34 ). The areas possess punctate ghost striae in prolongation of the marginal and adaxial striae (not devoid of structures or possessing a few irregularly distributed inconspicuous diffuse areolae). Marginal striae, composed of 2–4 areolae, are slightly radiate in proximal parts becoming convergent near the ends. Areolae ca. 14 in 10 µm. The punctate structures covering the lateral areas are not perforations but just shallow depressions. The terminal fissure is not simple, but a complicated curve towards the valve mantle ( Fig. 35 ).

Navicula hennedyi var. granulata Grunow in A. Schmidt (1874: pl. 3, fig. 3) is unquestionably not a basionym of the new taxon because it has a distinctively different valve outline, wider valves, almost 15 µm broad, irregularly punctuate lateral areas and, in particular, the central raphe ends are deflected to the primary side of the valve.

Type:— BLACK SEA. Crimea, Sevastopol, Omega Bay , station 19 (44 o 35’60”N, 33 o 26’50”E), depth 3 m, sandy substrate, Elena Nevrova , 28.07.200 4. (Holotype SZCZ slide 11094, illustrated in Fig. 31 ; isotype FR Eu- Black Sea 004 no. B152 Omega 12 003, illustrated in Fig. 35 ; praep. no. OM19 _04 in Coll. E. Nevrova, IBSS NASU, Sevastopol, Ukraine, isotype illustrated in Fig. 33 ) .

Etymology:— The species is dedicated to the late Professor Ninel Karayeva, outstanding diatomologist from Azerbaijan and the original author of the genus Lyrella .

Distribution: —Black Sea, marine species inhabiting sandy substrates, found at the south-western and south-eastern part of Crimea (e.g. Omega Bay, Balaklava Bay, Laspi Bay, Dvujakornaya Bay).

Figures

FIGURES 30–36: Figs 30-35: Lyrella karayevae sp. nov. Fig. 30: Valve view, LM, 630×, scale bar = 10 µm. Figs 31–34: Valve view, LM, 1000×, scale bar = 10 µm. Fig. 35: External view, SEM, scale bar = 10 µm. Holotype is illustrated in Fig. 31. Specimens from the Black Sea (Omega Bay, Laspi Bay, Balaklava Bay, Golubaya Bay). Fig. 36: Lyrella granulata comb. nov., stat. nov.: Reproduction of published line-drawing by Schmidt et al. 1874: pl. 3, fig. 3 as Navicula hennedyi var. granulata, scale bar = 10 µm.