FIGURES 153–156 in 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

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.