FIGURES 54–71 in New species and a new genus of the Orthoseirales from Patagonia, Argentina, with comments on systematic affinities within the Order

FIGURES 54–71. Orthoseira frenguellii spec. nov. Specimens of type population.54–64. LM. 65–71. SEM. 54–62. Valve views showing population variability. 54–55. Holotype. 63–64.Valves in girdle view. 65–67. External valve views. 65. Whole frustule in oblique view. 66. Detail of valve center showing external openings of carinoportulae (arrow). 67. Detail of valve in girdle view; note the thickened interstriae. 68–70. Internal valve views. 68. Whole valve. 69. Detail of valve center; note the internal opening of the carinoportula (arrow) and packed slits (arrowhead). 70. Detail of areolae showing the siliceous ingrowths on the foramina. 71. Valve in girdle view; note copulae with rows of poroids. Scale bars = 10 μm (Figs 54–65, 68, 71), 5 μm (Fig. 67), 2 μm (Fig. 66); 1 μm (Figs 69–70). Bar length is the same in all LM figures.