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Dubridinium cavatum
Dubridinium cavatum Reid, 1977
Matsuoka, 1984, considered this species to represent the encysted stage of Diplopsalopsis orbicularis (Paulsen, 1907) Meunier, 1909.
Holotype: Reid, 1977, pl.3, figs.35-37
Locus typicus: Barmouth, Wales, U.K.
Stratum typicum: Recent
Original diagnosis: Reid, 1977, p.450
Cavate, spherical or ovoid cysts. Inner capsule thin with a scabrate or finely microgranular surface. Periphragm membranous, may be close or distant from inner capsule, and may reflect the position of the girdle by forming two parallel folds. Within the pericoel granular inclusions are found which appear to act as supports for the outer membrane.
Original description: Reid, 1977, p.450
The test usually shows polar compression. An inner single layered capsule 0.7 Á thick has a scabrate surface ornament and is dark brown in colour. The periphragm is pale brown to colourless and may form ridges or folds delineating a girdle, ventral sulcus and apical horn. The girdle is excavated, circular and slightly inclined towards the posterior ventral sulcal depression. There is no evidence for a girdle on the inner capsule. Slight thickenings and folds in the outer membrane mark the apical pore scar. Granular inclusions within the pericoel vary in quantity, size and distribution. They may be semicontinuous forming a web over the inner capsule or appear as scattered granules in groups of 1 Ám¦ to 7 x 11 Ám. The archeopyle is delineated by a fracture along the upper edge of the cingulum in both the inner capsule and periphragm and almost completely circumscribes the cyst. The epitract and hypotract remain attached in the ventral area so that the epitract and hypotract appear to gape open in Iateral view.
Size: Holotype: complete cyst 54x60 Ám, inner capsule 54x56 Ám. Range of 18 specimens: complete cyst 49-63x47-63 Ám, inner capsule 42-58x35-58 Ám.
Matsuoka, 1984, considered this species to represent the encysted stage of Diplopsalopsis orbicularis (Paulsen, 1907) Meunier, 1909.
Holotype: Reid, 1977, pl.3, figs.35-37
Locus typicus: Barmouth, Wales, U.K.
Stratum typicum: Recent
Original diagnosis: Reid, 1977, p.450
Cavate, spherical or ovoid cysts. Inner capsule thin with a scabrate or finely microgranular surface. Periphragm membranous, may be close or distant from inner capsule, and may reflect the position of the girdle by forming two parallel folds. Within the pericoel granular inclusions are found which appear to act as supports for the outer membrane.
Original description: Reid, 1977, p.450
The test usually shows polar compression. An inner single layered capsule 0.7 Á thick has a scabrate surface ornament and is dark brown in colour. The periphragm is pale brown to colourless and may form ridges or folds delineating a girdle, ventral sulcus and apical horn. The girdle is excavated, circular and slightly inclined towards the posterior ventral sulcal depression. There is no evidence for a girdle on the inner capsule. Slight thickenings and folds in the outer membrane mark the apical pore scar. Granular inclusions within the pericoel vary in quantity, size and distribution. They may be semicontinuous forming a web over the inner capsule or appear as scattered granules in groups of 1 Ám¦ to 7 x 11 Ám. The archeopyle is delineated by a fracture along the upper edge of the cingulum in both the inner capsule and periphragm and almost completely circumscribes the cyst. The epitract and hypotract remain attached in the ventral area so that the epitract and hypotract appear to gape open in Iateral view.
Size: Holotype: complete cyst 54x60 Ám, inner capsule 54x56 Ám. Range of 18 specimens: complete cyst 49-63x47-63 Ám, inner capsule 42-58x35-58 Ám.