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Atopodinium chleuh
Atopodinium chleuh, (Below, 1981), Masure, 1991; Emendation as Maghrebinia chleuh: Masure, 1988a, p. 365-366
NOW Montanarocysta. Originally Maghrebinia, subsequently Atopodinium, thirdly (and now) Montanarocysta.
Holotype: Below, 1981a, pl.1, figs.5a-b; text-figs.13a-b; and Masure, 1988a, pl.2, figs.1-8; text-figs.3a-b; Fensome et al., 1991, figs.1-4 - p.619; Fauconnier and Masure, 2004, pl.9, figs.1-3.
Paratypes: Below, 1981
Locus typicus: Imi Quadder, Morocco
Stratum typicum: Vraconian-Cenomanian
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Original description as Maghrebinia chleuh: [Below, 1981, p. 22-23]: (Translations: LPP):
Diagnosis:
Chorate, bilayered cyst, consisting of, in outline, semispherical epicyst and slightly larger trapezoidal to nearly trigonal hypocyst. Periphragm and endophragm smooth to psilate. Parasutures bear isolated or sometimes proximally partially interconnected, perforate, distally polyfurcate processes. Along with four apicals, several precingulars and postcingulars, an antapical paraplate is fixed in this way. They are arranged as in Maghrebinia perforata (Clarke and Verdier, 1967) Below, 1981. Equatorially arranged processes of similar construction mark the spiral paracingulum. A very wide, undifferentiated parasulcal zone is developed ventrally.
An archaeopyle was not observed.
The surface is smooth to psilate.
Description (annotated):
Striking characteristic of the new species are the processes, arranged on the on the parasutures and paracingulum, consisting of coarsely perforated endophragm, standing on the smooth periphragm. They stand isolated gonally or they are proximally partially interconnected by low membranes. Hollow or solid at the bases, round or taeniate in cross section, they broaden distally and terminate unbranched with concave, convex or straight, finely denticulate margin, or are first and second order furcate. The processes correspond to the reinforcement band in the straight parasutural membranes in Magrebinia perforata (Clarke and Verdier, 1967) Below, 1981. Both species are thus related. Transitional forms with more or less strongly reduced membranes and numerous, isolated processes are present in the Moroccan material. Both species also correspond in paratabulation. Especially interesting is the apical region of M. chleuh, since because it helps to clarify the paraplate arrangement in M. perforata, which remained unclear due to the variable reduction of the apical processes: around the apex we find four processes. They are all considered remnants of membranes between the four apical paraplates. Posterior to these, a second crown of several (in the holotype 10) processes occurs - the remnants of hollow membranes between precingular and apical paraplates.
An archaeopyle was not observed in any specimen. Based on the relation to M. perforata, an apical archaeopyle can be expected.
Dimensions:
Holotype: Length (without processes) 55 µm; width (without processes) 48 µm; processes 12-18 µm; other specimens: length (without processes) 45-60 µm (average 53 µm); width (without processes) 40-54 µm (average 47 µm); processes 7-18 µm. 28 specimens.
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Emended description as Maghrebinia chleuh:
Masure, 1988, p. 365-366:
Diagnosis:
Chorate to proximochorate dinoflagellate cyst, acavate, subspherical, in outline rounded polygonal. Wall formed consisting of autophragm or closely appressed endophragm and periphragm, surface smooth to scabrate, granular at the bases of the processes. Paratabulation sexiform gonyaulacoid, indicated by intratabular, penitabular and parasutural processes. Ventral area undifferentiated. Processes granular and perforate, distally free, frequently interconnected proximally. Archaeopyle apical, type (tA)a, with accessory precingular sutures. Operculum composite adnate.
Description:
Chorate to proximochorate, subspherical cyst, slightly dorsoventrally compressed. The polygonal outline is rounded asymmetrical, the epicysts maller than the hypocyst. Wall consisting of autophragm or closely appressed endophragm and periphragm. Surface smooth to scabrate, granular at the bases of the processes. The granular and perforate processes, distally free, truncate or ramified, are frequently interconnected proximally. The paratabulation follows the sexiform gonyaulacoid model. According to the distribution of the processes, the apparent paratabulation is formed by 0-?2 preapical(s), 4 apicals, 6 precingulars, X cingulars, 5 postcingulars, ?1 postintercalary, 1 antapical, X sulcals. The sulcal paraplates and the sutures between the sulcus and adjacent paraplates (2, 1i, X, II and IV) are not expressed by reliefs. A preapical process may be present. Four or more processes ornament the apical penitabular processes, with adcingular interruptions, border the anterior part of the precingular paraplates. The sagging paracingulum is indicated by intratabular processes. Only the four postcingular parasutures II/III, III/IV, IV/V and V/VI bear processes. The antapical paraplate Y is delimited by parasutural processes; it may bear a bifid process.
The apical archaeopyle is of the (tA)a type, with accessory sutures developed between the precingulars. The composite opeculum is adnate.
Affinities:
Maghrebinia chleuh differs from the other Maghrebinia species in its distally isolated and proximally interconnected processes. According to Below, 1984, transitional forms between M. chleuh and M. mirabilis do exist.
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Modified description:
Masure, 1991, p. 65-66:
Slightly dorsoventrally compressed, subspheroidal, acavate, proximate dinocyst. A sexiform gonyaulacoid thecal tabulation is inferred. Paratabulation is incompletely delineated by penitabular rows of grana or gemmae and folds. These elements of relief suggest that the paratabulation is composed of ?0-2 preapical(s) (P,Q), I anterior intercalary (K) 4 apicals (lu,B,C,A), 6 precingulars (li, 2-6), X cingulars, 5-?6 postcingulars (?Iu, II-VI), ? I posterior intercalary (X), I antapical (Y), and X sulcals. The apical ornamentation is weakly expressed. Penitabular adcingular rows of grana or gemmae mark the edges of the precingular paraplates. Two rows of grana or gemmae mark the descending paracingulum. The ventral area is untabulated. The sulcal paraplates and the parasutures between the sulcus and the precingular (2, li), postcingular (Iu, II, VI) and posterior intercalary (X) paraplates are not expressed by surface features. Only four postcingular parasutures (II/III, III/IV, IV/V, V/VI) are expressed by penitabular ornament of adjacent paraplates in close contact with one another. The postcingular IV is below precingular 4, and the postcingular parasuture IV/V is aligned with the precingular 4/5. The antapical paraplate Y is more densely granulate than the rest of the cyst, invaginated Y imparts flattened shape to the antapex outline, and devaginated Y convex, rounded antapex. The apical archeopyle is of (tA)a type, with precingular accessory parasutures. The simple, polyplacoid operculum is adnate to the sulcal ai, and precingular 2 and Ii paraplates.
NOW Montanarocysta. Originally Maghrebinia, subsequently Atopodinium, thirdly (and now) Montanarocysta.
Holotype: Below, 1981a, pl.1, figs.5a-b; text-figs.13a-b; and Masure, 1988a, pl.2, figs.1-8; text-figs.3a-b; Fensome et al., 1991, figs.1-4 - p.619; Fauconnier and Masure, 2004, pl.9, figs.1-3.
Paratypes: Below, 1981
Locus typicus: Imi Quadder, Morocco
Stratum typicum: Vraconian-Cenomanian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Maghrebinia chleuh: [Below, 1981, p. 22-23]: (Translations: LPP):
Diagnosis:
Chorate, bilayered cyst, consisting of, in outline, semispherical epicyst and slightly larger trapezoidal to nearly trigonal hypocyst. Periphragm and endophragm smooth to psilate. Parasutures bear isolated or sometimes proximally partially interconnected, perforate, distally polyfurcate processes. Along with four apicals, several precingulars and postcingulars, an antapical paraplate is fixed in this way. They are arranged as in Maghrebinia perforata (Clarke and Verdier, 1967) Below, 1981. Equatorially arranged processes of similar construction mark the spiral paracingulum. A very wide, undifferentiated parasulcal zone is developed ventrally.
An archaeopyle was not observed.
The surface is smooth to psilate.
Description (annotated):
Striking characteristic of the new species are the processes, arranged on the on the parasutures and paracingulum, consisting of coarsely perforated endophragm, standing on the smooth periphragm. They stand isolated gonally or they are proximally partially interconnected by low membranes. Hollow or solid at the bases, round or taeniate in cross section, they broaden distally and terminate unbranched with concave, convex or straight, finely denticulate margin, or are first and second order furcate. The processes correspond to the reinforcement band in the straight parasutural membranes in Magrebinia perforata (Clarke and Verdier, 1967) Below, 1981. Both species are thus related. Transitional forms with more or less strongly reduced membranes and numerous, isolated processes are present in the Moroccan material. Both species also correspond in paratabulation. Especially interesting is the apical region of M. chleuh, since because it helps to clarify the paraplate arrangement in M. perforata, which remained unclear due to the variable reduction of the apical processes: around the apex we find four processes. They are all considered remnants of membranes between the four apical paraplates. Posterior to these, a second crown of several (in the holotype 10) processes occurs - the remnants of hollow membranes between precingular and apical paraplates.
An archaeopyle was not observed in any specimen. Based on the relation to M. perforata, an apical archaeopyle can be expected.
Dimensions:
Holotype: Length (without processes) 55 µm; width (without processes) 48 µm; processes 12-18 µm; other specimens: length (without processes) 45-60 µm (average 53 µm); width (without processes) 40-54 µm (average 47 µm); processes 7-18 µm. 28 specimens.
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Emended description as Maghrebinia chleuh:
Masure, 1988, p. 365-366:
Diagnosis:
Chorate to proximochorate dinoflagellate cyst, acavate, subspherical, in outline rounded polygonal. Wall formed consisting of autophragm or closely appressed endophragm and periphragm, surface smooth to scabrate, granular at the bases of the processes. Paratabulation sexiform gonyaulacoid, indicated by intratabular, penitabular and parasutural processes. Ventral area undifferentiated. Processes granular and perforate, distally free, frequently interconnected proximally. Archaeopyle apical, type (tA)a, with accessory precingular sutures. Operculum composite adnate.
Description:
Chorate to proximochorate, subspherical cyst, slightly dorsoventrally compressed. The polygonal outline is rounded asymmetrical, the epicysts maller than the hypocyst. Wall consisting of autophragm or closely appressed endophragm and periphragm. Surface smooth to scabrate, granular at the bases of the processes. The granular and perforate processes, distally free, truncate or ramified, are frequently interconnected proximally. The paratabulation follows the sexiform gonyaulacoid model. According to the distribution of the processes, the apparent paratabulation is formed by 0-?2 preapical(s), 4 apicals, 6 precingulars, X cingulars, 5 postcingulars, ?1 postintercalary, 1 antapical, X sulcals. The sulcal paraplates and the sutures between the sulcus and adjacent paraplates (2, 1i, X, II and IV) are not expressed by reliefs. A preapical process may be present. Four or more processes ornament the apical penitabular processes, with adcingular interruptions, border the anterior part of the precingular paraplates. The sagging paracingulum is indicated by intratabular processes. Only the four postcingular parasutures II/III, III/IV, IV/V and V/VI bear processes. The antapical paraplate Y is delimited by parasutural processes; it may bear a bifid process.
The apical archaeopyle is of the (tA)a type, with accessory sutures developed between the precingulars. The composite opeculum is adnate.
Affinities:
Maghrebinia chleuh differs from the other Maghrebinia species in its distally isolated and proximally interconnected processes. According to Below, 1984, transitional forms between M. chleuh and M. mirabilis do exist.
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Modified description:
Masure, 1991, p. 65-66:
Slightly dorsoventrally compressed, subspheroidal, acavate, proximate dinocyst. A sexiform gonyaulacoid thecal tabulation is inferred. Paratabulation is incompletely delineated by penitabular rows of grana or gemmae and folds. These elements of relief suggest that the paratabulation is composed of ?0-2 preapical(s) (P,Q), I anterior intercalary (K) 4 apicals (lu,B,C,A), 6 precingulars (li, 2-6), X cingulars, 5-?6 postcingulars (?Iu, II-VI), ? I posterior intercalary (X), I antapical (Y), and X sulcals. The apical ornamentation is weakly expressed. Penitabular adcingular rows of grana or gemmae mark the edges of the precingular paraplates. Two rows of grana or gemmae mark the descending paracingulum. The ventral area is untabulated. The sulcal paraplates and the parasutures between the sulcus and the precingular (2, li), postcingular (Iu, II, VI) and posterior intercalary (X) paraplates are not expressed by surface features. Only four postcingular parasutures (II/III, III/IV, IV/V, V/VI) are expressed by penitabular ornament of adjacent paraplates in close contact with one another. The postcingular IV is below precingular 4, and the postcingular parasuture IV/V is aligned with the precingular 4/5. The antapical paraplate Y is more densely granulate than the rest of the cyst, invaginated Y imparts flattened shape to the antapex outline, and devaginated Y convex, rounded antapex. The apical archeopyle is of (tA)a type, with precingular accessory parasutures. The simple, polyplacoid operculum is adnate to the sulcal ai, and precingular 2 and Ii paraplates.