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Lejeunecysta denticulata
From Fensome et al., 2019:
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Original Description Morgenroth et al., 2008:
Derivation of name: Latin, denticulus, small tooth, with reference to the denticulate cingulum.
Holotype: Pl. 7, Figs 12, 13. Sample CP-24, single grain slide CP-24/5.
Paratypes: Single grain slides CP-24/3, CP-24/4, CP-25/7, CP-25/21, CP-25/66 and CP-25/76, samples CP-24 and CP-25.
Type locality: Cipamingkis River, West Java (Text-fig. 2). Cisubuh Formation, Late Miocene, Age-N17.
Diagnosis: An intermediate species of Lejeunecysta with a smooth autophragm and a cingulum marked by two parallel denticulate ridges which are interrupted on the ventral side of the cyst. Apex flattened or slightly rounded, antapical horns of about equal length and pointed. Archeopyle intercalary.
Description: Cysts proximate, peridinoid in outline, compressed dorsoventrally, pentagonal. Epicyst about equal to hypocyst, with convex to straight sides. Hypocyst with straight to concave sidesand with two pointed antapical horns of about equal length; antapical depression prominent. Apical horn short, mostly truncate, on some specimens pointed. Cingulum defined by two parallel ridges, both of which are clearly
denticulate. Cingulum interrupted on the ventral side by the unornamented parasulcus. Only a few specimens show a precingular intercalary archeopyle, which seems to correspond to 2a, located mid-dorsal and almost extending to the cingulum.
Dimensions: Length of autoblast 54 (63) 74 μm, holotype 65 μm, width of autoblast 50 (75) 95 μm,
holotype 75 μm. 25 specimens measured.
Comparison: Lejeunecysta cinctoria (BUJAK 1980) LENTIN and WILLIAMS 1981 described from the Late Eocene of England and reported from the Oligocene of the Niger Delta has also a denticulate cingulum but can be distinguished from the new species by the different shape and smaller size of the cyst, and the apical horn (BIFFI & GRIGNANI 1983: 130, pl. 3, fig. 6). Lejeunecysta denticulata differs from Lejeunecysta tenella (MORGENROTH) LENTIN and WILLIAMS in the smooth autophragm, lacking spines, although both species have a denticulate cingulum (MORGENROTH, 1966b: 4, pl. 1, fig. 8). Lejeunecysta paratenella BENEDEK has denticles restricted to the lower ridge of the cingulum (BENEDEK 1972: 41, text-fig. 18). Lejeunecysta lata BIFFI and GRIGNANI from the Oligocene of the Niger Delta has a paracingulum, which is sometimes slightly denticular. However, the species is considerably larger (BIFFI & GRIGNANI 1983: 136).
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Original Description Morgenroth et al., 2008:
Derivation of name: Latin, denticulus, small tooth, with reference to the denticulate cingulum.
Holotype: Pl. 7, Figs 12, 13. Sample CP-24, single grain slide CP-24/5.
Paratypes: Single grain slides CP-24/3, CP-24/4, CP-25/7, CP-25/21, CP-25/66 and CP-25/76, samples CP-24 and CP-25.
Type locality: Cipamingkis River, West Java (Text-fig. 2). Cisubuh Formation, Late Miocene, Age-N17.
Diagnosis: An intermediate species of Lejeunecysta with a smooth autophragm and a cingulum marked by two parallel denticulate ridges which are interrupted on the ventral side of the cyst. Apex flattened or slightly rounded, antapical horns of about equal length and pointed. Archeopyle intercalary.
Description: Cysts proximate, peridinoid in outline, compressed dorsoventrally, pentagonal. Epicyst about equal to hypocyst, with convex to straight sides. Hypocyst with straight to concave sidesand with two pointed antapical horns of about equal length; antapical depression prominent. Apical horn short, mostly truncate, on some specimens pointed. Cingulum defined by two parallel ridges, both of which are clearly
denticulate. Cingulum interrupted on the ventral side by the unornamented parasulcus. Only a few specimens show a precingular intercalary archeopyle, which seems to correspond to 2a, located mid-dorsal and almost extending to the cingulum.
Dimensions: Length of autoblast 54 (63) 74 μm, holotype 65 μm, width of autoblast 50 (75) 95 μm,
holotype 75 μm. 25 specimens measured.
Comparison: Lejeunecysta cinctoria (BUJAK 1980) LENTIN and WILLIAMS 1981 described from the Late Eocene of England and reported from the Oligocene of the Niger Delta has also a denticulate cingulum but can be distinguished from the new species by the different shape and smaller size of the cyst, and the apical horn (BIFFI & GRIGNANI 1983: 130, pl. 3, fig. 6). Lejeunecysta denticulata differs from Lejeunecysta tenella (MORGENROTH) LENTIN and WILLIAMS in the smooth autophragm, lacking spines, although both species have a denticulate cingulum (MORGENROTH, 1966b: 4, pl. 1, fig. 8). Lejeunecysta paratenella BENEDEK has denticles restricted to the lower ridge of the cingulum (BENEDEK 1972: 41, text-fig. 18). Lejeunecysta lata BIFFI and GRIGNANI from the Oligocene of the Niger Delta has a paracingulum, which is sometimes slightly denticular. However, the species is considerably larger (BIFFI & GRIGNANI 1983: 136).