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Rimosicysta sp.
Rimosicysta sp.
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Rimosicysta? sp. A
Figured in Marshall 1989: Plate 5, figs. 6-10; Text-Figure 14
Description. Marshall 1989, p. 50
Cysts compressed dorsoventrally; dorsal surface markedly convex and bearing a middorsal bulge. Dorsoventral outline uncertain, highly irregular. Cysts bilayered. Endocyst occupies center of pericyst, dorsoventral outline subtriangular. Periphragm forming a flange around periphery of cyst, no pericoel evident. Both wall layers smooth; periphragm strongly crumpled, 0.2-0.4 µm thick, with scattered perforations less than 1 µm in diameter; endophragm ca. 0.5 µm thick.
Size. Maximum dimension of pericyst 100(111)125 µm, endocyst 51(56)61 µm; 6 specimens measured.
Comparison. Marshall 1989, p. 50
Although only six specimens of this form were observed, the presence of two wall layers and the shape of the pericyst distinguish it from species of the genus with gently curved outlines, such as Rimosicysta eversa, R. kipperii, and R. ? ovata. The lack of consistency in pericyst outline prevents more detailed comparisons with these taxa. This form is questionably assigned to Rimosicosta rather than Limbicysta because it lacks pronounced horns.
Occurrence. Cook Cruise sample C4/87 21DDa.
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Rimosicysta? sp. A
Figured in Marshall 1989: Plate 5, figs. 6-10; Text-Figure 14
Description. Marshall 1989, p. 50
Cysts compressed dorsoventrally; dorsal surface markedly convex and bearing a middorsal bulge. Dorsoventral outline uncertain, highly irregular. Cysts bilayered. Endocyst occupies center of pericyst, dorsoventral outline subtriangular. Periphragm forming a flange around periphery of cyst, no pericoel evident. Both wall layers smooth; periphragm strongly crumpled, 0.2-0.4 µm thick, with scattered perforations less than 1 µm in diameter; endophragm ca. 0.5 µm thick.
Size. Maximum dimension of pericyst 100(111)125 µm, endocyst 51(56)61 µm; 6 specimens measured.
Comparison. Marshall 1989, p. 50
Although only six specimens of this form were observed, the presence of two wall layers and the shape of the pericyst distinguish it from species of the genus with gently curved outlines, such as Rimosicysta eversa, R. kipperii, and R. ? ovata. The lack of consistency in pericyst outline prevents more detailed comparisons with these taxa. This form is questionably assigned to Rimosicosta rather than Limbicysta because it lacks pronounced horns.
Occurrence. Cook Cruise sample C4/87 21DDa.
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