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Lejeunecysta mariae
From Fensome et al., 2019:
Lejeunecysta mariae (Harland in Harland et al., 1991, p.653, figs.4j–l) Lentin and Williams, 1993, p.383. Holotype: Harland et al., 1991, fig.4j. Originally Protoperidinium subgenus Protoperidinium section Lejeunecysta (section name not validly published; Appendix B), subsequently (and now) Lejeunecysta. Contrary to the opinion of Lentin and Williams (1993, p.383), the name Protoperidinium marieae was validly published in Harland in Harland et al. (1991) since, although Lejeunecysta as a section name was not validly published, the species was assigned to the validly published generic name Protoperidinium. Age: Early Pleistocene.
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Original description: [Harland et al., 1991]:
Protoperidinium (Protoperidinium sect. Lejeunecysta) mariea sp.nov.
Figure 4j, k, 1
Derivation of name. Named for Ms L. M. Fowler.
Description. Small, pale brown, peridinioid cyst of autophragm. Wall smooth but conspicuously thickened at the apex and antapex. Epicyst larger than hypocyst, conical with convex sides. Apical horn occurs as a low rounded cone, always thickened. Hypocyst carries two antapical horns whose tips are always thickened into a solid, low round cone or as an elongate spine that may be short or long, erect or flexuous. Cyst often folded along the line of the paracingulum. Left antapical horn larger than the right. Parasulcus marked by low depression but otherwise not conspicuous. Paracingulum occurs as a slight depression but usually only seen on the lateral ambitus, may be delineated by rows of granules along the anterior and posterior paracingular margins. Archeopyle intercalary formed by the loss of paraplate 2a, may be standard or broad hexa in style, and open or with the operculum in place.
Holotype. Figure 4j; Early Pleistocene, specimen MPK 5618, at 66.5 m, BGS Ormesby Borehole.
Dimensions. Holotype: Length 43 m, breadth 38 em.
Range: Length 34 (40.4) 50 μm, sqrt(n-1) = 5.1; breadth 34 (37.4) 40 μm, sqrt(n-1) = 1.9; n = 9.
Occurrence. P. (P.) mariea is included in the Protoperidinium spp. count and has an effective last occurrence at 53.0 m. It occurs throughout units A to D.
Remarks. The cyst is characterized by its small size, apical and antapical thickenings, the latter often developed into antapical spines, and a large epicyst which is usually conspicuous because of folding along the paracingulum. The cysts are somewhat similar to Lejeunecysta communis Biffi and Grignani, a much larger cyst with equally developed epi- and hypocyst, and L. pulchra Biffi and Grignani again a larger cyst, of more globose habit with no apical thickenings. Selenopemphix sp. of Corradini & Biffi (1988, plate 4, fig. 10) from the Pliocene of Cava Serredi, Italy may
be conspecific with P. mariea. Cristadinium diminutiuum Head, Norris & Mudie, 1989 is also similar but differs in possessing epicystal crests and a granulate autophragm.
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Supplemental description: Head, 1993, p.31
Cysts light brown in color, wall thin and composed of two closely appressed layers. Wall surface moderately to faintly granulate under LM: under SEM surface bears granules/gemmae (0.5 µm or less in diameter) which are themselves covered in minute (<0.1 µm) granules that densely cover entire surface. Blunt spines less than 1.0 µm high occur along paracingular margins and may also be present elsewhere. Epicystlonger than hypocyst, conical and with convex sides. Apical horn weakly developed and indicated by a slightly thickened (< 1.5 µm) apical boss. Hypocyst outline rounded trapezoidal in dorsoventral view, with two equally developed antapical horns that are moderately to strongly divergent and bear solid, acuminate tips. Paracingulum fairly pronounced and indicated by transverse folding. Parasulcus is shallow. Archeopyle intercalary hexa 2a isodeltaform with short H3 and H5 sides; operculum free, sometimes adherent on adcingular margin. There are no other indications of paratabulation.
Dimensions.--Length, 27(36.8)47 µm; width, 27(33.4)38 µm; antapical horn tip length (from base of solid thickening), 1.7(4.1)5.7 µm. Twenty-two specimens measured.
Comparison.--This species most closely compares with Lejeunecysta convexa Matsuoka and Bujak, 1988, described from the upper Oligocene to lower Miocene of the Bering Sea. Lejeunecysta convexa differs in its larger average size (length, 46-59 µm, albeit overlapping with L. mariea), smooth wall surface, and an archeopyle stated to be trapezoidal (Matsuoka and Bujak, 1988, p. 57 and text-fig. 11). Lejeunecysta pulchra Biffi and Grignani, 1983, described from the Oligocene of the Niger Delta is also larger (length, 55-80 µm) than L. mariea and has a smooth wall surface.
Lejeunecysta mariae (Harland in Harland et al., 1991, p.653, figs.4j–l) Lentin and Williams, 1993, p.383. Holotype: Harland et al., 1991, fig.4j. Originally Protoperidinium subgenus Protoperidinium section Lejeunecysta (section name not validly published; Appendix B), subsequently (and now) Lejeunecysta. Contrary to the opinion of Lentin and Williams (1993, p.383), the name Protoperidinium marieae was validly published in Harland in Harland et al. (1991) since, although Lejeunecysta as a section name was not validly published, the species was assigned to the validly published generic name Protoperidinium. Age: Early Pleistocene.
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Original description: [Harland et al., 1991]:
Protoperidinium (Protoperidinium sect. Lejeunecysta) mariea sp.nov.
Figure 4j, k, 1
Derivation of name. Named for Ms L. M. Fowler.
Description. Small, pale brown, peridinioid cyst of autophragm. Wall smooth but conspicuously thickened at the apex and antapex. Epicyst larger than hypocyst, conical with convex sides. Apical horn occurs as a low rounded cone, always thickened. Hypocyst carries two antapical horns whose tips are always thickened into a solid, low round cone or as an elongate spine that may be short or long, erect or flexuous. Cyst often folded along the line of the paracingulum. Left antapical horn larger than the right. Parasulcus marked by low depression but otherwise not conspicuous. Paracingulum occurs as a slight depression but usually only seen on the lateral ambitus, may be delineated by rows of granules along the anterior and posterior paracingular margins. Archeopyle intercalary formed by the loss of paraplate 2a, may be standard or broad hexa in style, and open or with the operculum in place.
Holotype. Figure 4j; Early Pleistocene, specimen MPK 5618, at 66.5 m, BGS Ormesby Borehole.
Dimensions. Holotype: Length 43 m, breadth 38 em.
Range: Length 34 (40.4) 50 μm, sqrt(n-1) = 5.1; breadth 34 (37.4) 40 μm, sqrt(n-1) = 1.9; n = 9.
Occurrence. P. (P.) mariea is included in the Protoperidinium spp. count and has an effective last occurrence at 53.0 m. It occurs throughout units A to D.
Remarks. The cyst is characterized by its small size, apical and antapical thickenings, the latter often developed into antapical spines, and a large epicyst which is usually conspicuous because of folding along the paracingulum. The cysts are somewhat similar to Lejeunecysta communis Biffi and Grignani, a much larger cyst with equally developed epi- and hypocyst, and L. pulchra Biffi and Grignani again a larger cyst, of more globose habit with no apical thickenings. Selenopemphix sp. of Corradini & Biffi (1988, plate 4, fig. 10) from the Pliocene of Cava Serredi, Italy may
be conspecific with P. mariea. Cristadinium diminutiuum Head, Norris & Mudie, 1989 is also similar but differs in possessing epicystal crests and a granulate autophragm.
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Supplemental description: Head, 1993, p.31
Cysts light brown in color, wall thin and composed of two closely appressed layers. Wall surface moderately to faintly granulate under LM: under SEM surface bears granules/gemmae (0.5 µm or less in diameter) which are themselves covered in minute (<0.1 µm) granules that densely cover entire surface. Blunt spines less than 1.0 µm high occur along paracingular margins and may also be present elsewhere. Epicystlonger than hypocyst, conical and with convex sides. Apical horn weakly developed and indicated by a slightly thickened (< 1.5 µm) apical boss. Hypocyst outline rounded trapezoidal in dorsoventral view, with two equally developed antapical horns that are moderately to strongly divergent and bear solid, acuminate tips. Paracingulum fairly pronounced and indicated by transverse folding. Parasulcus is shallow. Archeopyle intercalary hexa 2a isodeltaform with short H3 and H5 sides; operculum free, sometimes adherent on adcingular margin. There are no other indications of paratabulation.
Dimensions.--Length, 27(36.8)47 µm; width, 27(33.4)38 µm; antapical horn tip length (from base of solid thickening), 1.7(4.1)5.7 µm. Twenty-two specimens measured.
Comparison.--This species most closely compares with Lejeunecysta convexa Matsuoka and Bujak, 1988, described from the upper Oligocene to lower Miocene of the Bering Sea. Lejeunecysta convexa differs in its larger average size (length, 46-59 µm, albeit overlapping with L. mariea), smooth wall surface, and an archeopyle stated to be trapezoidal (Matsuoka and Bujak, 1988, p. 57 and text-fig. 11). Lejeunecysta pulchra Biffi and Grignani, 1983, described from the Oligocene of the Niger Delta is also larger (length, 55-80 µm) than L. mariea and has a smooth wall surface.