Cerataulus strelnikovae P.A. Sims & D. M. Williams, 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 : 44

Cerataulus strelnikovae P.A. Sims & D. M. Williams sp. nov. ( Figs 152–153 )

Valves bipolar, apices with short, squat elevations facing opposite directions, rimmed ocellus slanted dorsally on summit ( Fig. 152 ). Valves distinctly convex with valve centre flattening out. Valve structure loculate with well-developed annulus extending between elevations ( Fig. 152 , arrow). Exterior valve surface with transapical rows of fine pores extending from central annulus to valve margin, within annulus irregularly arranged, interior with foramina. Valve surface covered with spinules, those within annulus linked ( Fig. 153 ). Rimoportulae 4–6, positioned either side of annulus, opening through stout, long tubular spines on valve exterior, internal opening unknown. Girdle bands unknown.

Type:— Vema Cruise 17, core 107, water depth 1525m [ CAS nos 39573/9 & 10] ( BM 101831, holotype, designated here).

Observations:— This description is based on specimens from type material: Vema Cruise 17, core 107.

Figures

FIGURES 148–152. Ralfsiella smithii (=Cerataulus smithii Ralfs in Pritchard) (Beaufort, South Carolina, USA). Fig. 148. Circular valve face with opposing narrow submarginal elevations; positioned midway submarginal hollow spines, the exterior openings of rimoportulae; valve surface covered in a mostly radial pattern of false pseudoloculi, valve mantle slightly indented where it joins narrow hyaline valve margin; scale bar = 10 μm. Fig. 149. Summit of elevation with rimmed ocellus; scale bar = 2 μm. Fig. 150. Frustule with attached girdle bands, flat valve face merging into rounded mantle, barely raised elevations; scale bar = 10 μm. Fig. 151. Irregular false pseudoloculi, basal layer with a single poroid areola occluded by a simple raised cribrum; scale bar = 1 μm.

FIGURES 153–156. Details of two species currently placed in Cerataulus but with characters associated with Trieres and Parodontella. Figs 153,155.Cerataulus strelnikovae P.A. Sims and D.M. Williams, sp. nov. (Vema Cruise 17, core 107, 175cm). Fig. 152. Valve exterior, broadly lanceolate valve with apical elevations lying in opposing directions, 5 stout subcentral spines, the openings of rimoportulae surrounding a central annulus; scale bar = 10 μm. Fig. 155. Detail of transapical rows of irregularly arranged fine poresr within annulus, linked spinules covering annulus (sternum); scale bar = 1 μm. Figs 154–156. Cerataulus granulata (Roper) P.A. Sims & D.M. Williams, comb. nov. (“Wunderluss”, locality unknown, ex Brigger colln, BM). Fig. 154. Valve exterior, lanceolate valve with elevations in opposing directions, an ocellus on summit, 2 stout hollow spines, the openings of rimoportulae lying centrally in a subpolar position on opposing sides of a central sternum; scale bar = 10 μm. Fig. 155. Detail of valve exterior with transapical quadruple rows of fine pores meeting annulus (sternum) extending between rimoportulae; scale bar = 1 μm.