Parodontella ruthenica (Witt) D. M. Williams & P.A. Sims, 2018

Sims, Pat A., Williams, David M. & Ashworth, Matt, 2018, Examination of type specimens for the genera Odontella and Zygoceros (Bacillariophyceae) with evidence for the new family Odontellaceae and a description of three new genera, Phytotaxa 382 (1), pp. 1-56 : 13

Parodontella ruthenica (Witt) D. M. Williams & P.A. Sims , comb. nov. ( Figs 36–43 )

Basionym:— Biddulphia ruthenica Witt (1885: 158 , pl. 9, figs 9, 10)

Synonym:— Denticella ruthenica (Witt) De Toni (1894: 885)

Type:— Simbirsk ( Witt 1885)

Valves broadly lanceolate with narrow outwardly directed elevations at apices and several long, hollow, curved spines on valve face, exterior openings of rimoportulae ( Figs 36, 38, 42 ); length 80–225μm, breadth 30–105μm; striae on exterior c. 14 in 10μm. Valve face lanceolate bordered by well-developed marginal ridge of spines fused at base separating valve face from deep slightly expanded mantle ( Figs 36–38 ). Summits of elevations with small rounded hyaline area on proximal face, ocellus on distal face ( Fig. 41 ).Areolae loculate with internal foramina ( Fig. 40 ), exterior with bi- or tri-seriate rows of fine pores ( Fig. 37 ). On mantle fine pores lie within rectangular areas bordered by slightly raised longitudinal costae with transverse bars ( Fig. 37 ). On valve face in bi-seriate transapical lines meeting central sternum ( Fig. 37 , arrow). Spinules on valve face and elevations ( Figs 36–38 ). Rimoportulae 4–11 ( Fig. 39 ), opening to exterior through long curved spines lying just within marginal ridge ( Fig. 38 ), on interior each opening through a transverse slit across a papillus ( Fig. 40 ).

Observations:— The description above is based on material from Moreno, California, USA ( BM).

Figures

FIGURES 36–43. Parontella ruthenica (Witt) D. M. Williams & P.A. Sims (Moreno, California, USA). Fig. 36. Exterior tilted with outwardly directed elevations at apices, marginal ridge of spines, ten long submarginal hollow spines (openings from rimoportulae); scale bar = 50 μm. Fig. 37. Valve face with transapical rows of loculi meeting at central sternum (arrow) and mantle with lines of poroids bound by barely raised longitudinal costae; scale bar = 15 μm. Fig. 38. Vale exterior tilted with 7 long hollow submarginal spines and spinules on valve face; scale bar = 43 μm. Fig. 39. Valve interior with openings from 9 rimoportulae and marginal ridge of fused spines; scale bar = 50 μm. Fig. 40. Interior with foramina and openings of two rimoportulae; scale bar = 6 μm. Fig. 41. Elevation with flattened summit and ocellus on distal face; scale bar = 5 μm. Figs 42–43. B.M. 52964, specimens from Ananino, Simbirsk. Fig. 42. Valve face 121 μm x 58 μm. Fig. 43. Mantle view, specimen 95 μm long.