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Selenopemphix indentata
Selenopemphix? indentata Head et al., 1989
Head et al., 1989 questionably included this species in Selenopemphix.
Holotype: Head et al., 1989, pl.1, fig.1
Locus typicus: ODP leg 105, site 646, Labrador Sea
Stratum typicum: Late Miocene
Original diagnosis: Head et al., 1989, p.460
Cysts polar compressed and having a subspherical outline. Wall closely appressed biphragmal, light brown in color, with the periphragm much thinner than the endophragm. Wall surface is smooth to faintly granulate. Appressed paracingular folds (crests) surround the cyst, except in the sulcal region. Concave rounded indentations occur in the endophragm along the distal margins of the paracingular crests. Indentations are not present in the periphragm. Archeopyle is a large rounded hexa-intercalary.
Dimensions. Holotype: maximum diameter, including crests, 44 µm. Range in maximum diameter, including crests, 34(41.5)49 µm. Crest height up to around 5 µm. Nineteen specimens were measured.
Original description: Head et al., 1989, p.460
Each of the two paracingular crests that run around the perimeter of the cyst is considered to be an appressed fold, although it might be a thin solid crest. Indentations of the crest margin are rather irregularly spaced. They generally extend for about one-half the height of the crest. The presence of a very thin periphragm is only clearly seen around the cyst margin, where it overlies the indented portion of the endophragm. It provides the cyst with an entire equatorial margin in plan view. The archeopyle was rarely observed because of adherence of the operculum in most specimens. Based on a few observations, it appears to be a large hexa-intercalary, offset relative to the dorsoventral midline and typical of the genus Selenopemphix.
Discussion. The presence of broad, concave endophragmal indentations around the paracingular crests distinguishes this species from all other species of Selenopemphix. Both Selenopemphix and the dorsoventrally compressed Lejeunecysta were erected for autophragmal cyst species, although careful study of some of these might reveal a closely appressed biphragmal wall.
Head et al., 1989 questionably included this species in Selenopemphix.
Holotype: Head et al., 1989, pl.1, fig.1
Locus typicus: ODP leg 105, site 646, Labrador Sea
Stratum typicum: Late Miocene
Original diagnosis: Head et al., 1989, p.460
Cysts polar compressed and having a subspherical outline. Wall closely appressed biphragmal, light brown in color, with the periphragm much thinner than the endophragm. Wall surface is smooth to faintly granulate. Appressed paracingular folds (crests) surround the cyst, except in the sulcal region. Concave rounded indentations occur in the endophragm along the distal margins of the paracingular crests. Indentations are not present in the periphragm. Archeopyle is a large rounded hexa-intercalary.
Dimensions. Holotype: maximum diameter, including crests, 44 µm. Range in maximum diameter, including crests, 34(41.5)49 µm. Crest height up to around 5 µm. Nineteen specimens were measured.
Original description: Head et al., 1989, p.460
Each of the two paracingular crests that run around the perimeter of the cyst is considered to be an appressed fold, although it might be a thin solid crest. Indentations of the crest margin are rather irregularly spaced. They generally extend for about one-half the height of the crest. The presence of a very thin periphragm is only clearly seen around the cyst margin, where it overlies the indented portion of the endophragm. It provides the cyst with an entire equatorial margin in plan view. The archeopyle was rarely observed because of adherence of the operculum in most specimens. Based on a few observations, it appears to be a large hexa-intercalary, offset relative to the dorsoventral midline and typical of the genus Selenopemphix.
Discussion. The presence of broad, concave endophragmal indentations around the paracingular crests distinguishes this species from all other species of Selenopemphix. Both Selenopemphix and the dorsoventrally compressed Lejeunecysta were erected for autophragmal cyst species, although careful study of some of these might reveal a closely appressed biphragmal wall.