FIGURES 48–57 in Pseudostaurosira crateri sp. nov. (Fragilariaceae, Bacillariophyta), a new small araphid, fossil diatom species from the Pleistocene (Atlantic Forest, Brazil)

FIGURES 48–57. SEM micrographs of Pseudostaurosira crateri Marquardt & C.E.Wetzel sp. nov. from type material (holotype SP365.548) sampled from Colônia Basin, São Paulo, Brazil: (48–51) Overall characteristics of the outer surface of the valve face. Notice an apical pore field on each valve end and striae each composed of one areola on valve face and two to three on mantle (50, 51). Arrow 1 points to the volae in the inner perimeter of the areolae (50). Arrow 2 points to the rudimentary or incipient spines located on the virgae (50–52). Girdle view of a frustule showing characteristics of the cingulum. Notice (arrow 3) open girdle bands (52). Detail of the areolae open into a single depression (arrow 4) running from valve face to mantle (53). Inner valve surface showing absence of rimoportulae and areolae characteristics (55–57). Notice internal detail (arrow 5) of superimposed disks formed by depositions of siliceous material on the volae (57). Detail (arrow 6) of apical pore field (57).