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Maghrebinia
From Williams et al., 2017:
[Maghrebinia, Below, 1981a, p. 22; Emendation: Masure, 1988a, p. 362–363.
Type species: originally as Dinopterygium perforatum, Clarke and Verdier, 1967 (pl.6, figs.1–2)] ; Maghrebinia perforata, emend. Below, 1981; emend. Masure, 1988
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Original description: [Below, 1981]: (Translation: Stover and Williams, 1987, p. 154):
Diagnosis:
Cysts are acavate, chorate to proximochorate, lenticular, two-layered, with spheroidal to hexagonal outlines. Paratabulation determined as 4`, 4``, Oc, 4``,1````, 0s. Additional precingular and postcingular paraplates possibly integrated within the broad,undifferentiated ventral sulcal zone. Paracingulum not subdivided, marked by a single, high, often incised membrane, which is also parasutural. Intersections of parasutural membranes are often reinforced. With the exception of the supported gonal lists, partial and complete reduction of the septa is possible. Archeopyle apical type A.
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Modified description:
Stover and Williams, 1987, p. 153:
Synopsis:
Cysts proximochorate to skolochorate, lenticular; body with continuous or discontinuous parasutural septa or processes; some of the latter are gonal whereas the apical processes appear to be intratabular; paratabulation indicated by parasutural features and presumably intratabular processes, formula: 3`-?4`, 4-5``, Xc, 4```,1``````; archeopyle apical, type [tA], operculum free.
Description:
Shape: Body lenticular, outline subcircular to elliptical; septate forms may have a somewhat hexagonal outline.
Wall relationships: Wall layers appressed except where septa or processes are formed.
Wall features: Parasutural features consist of continuous or discontinuous septa, together with simple and branched processes which may be isolated or connected distally. Processes in the apical area apparently intratabular; surface features and/ or wall layers smooth, or perforate. Mid-dorsal and mid-ventral areas more or less without septa or processes.
Archeopyle: Apical, type [tA]; trace of principal archeopyle suture unknown.
Paratabulation: Indicated by parasutural features and presumably intratabular processes in the apical area; formula: 3-?4`, 4-5", Xc, 4"`,1"".
Paracingulum: Expressed by single transverse septum or by equatorial processes, of which some are clearly wider than others.
Parasulcus: Apparently lies within broad, undifferentiated ventral area free of septa and processes.
Size: Intermediate; width including processes and septa, about 65 µm to nearly 100 µm.
Affinities:
Maghrebinia is similar to Cyclonephelium Deflandre and Cookson 1955 emended Stover and Evitt 1978 in having a lenticular body and relatively large medial, process-free areas on the dorsal and ventral surfaces. Cyclonephelium does not have 3 or 4 isolated processes within the apical area as on Maghrebinia, however, and the outline of the archeopyle in Cyclonephelium clearly indicates the presence of 6 precingular paraplates. Because the shape of the archeopyle is unknown and more precise information about the paratabulation of Maghrebinia is not available, no additional comparative remark is offered.
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Emended description:
Masure, 1988: (Translation: Fensome et al., 1991, p. 340-341, LPP (affinities)):
Diagnosis:
Acavate dinoflagellate cyst, chorate to proximate, subspherical, in outline polugonal to oval. Wall formed by autophragm or by closely appressed endophragm and periphragm, outer surface smooth to granulate. Paratabulation sexiform gonyaulacoid, reflected by septa and/or intratabular, penitabular and parasutural processes. Ventral area not tabulated by the reliefs, undifferentiated. Archaeopyle apical, type (tA)a, with accessory precingular sutures. Operculum composite adnate.
Description:
Shape: Subspherical cyst, slightly compressed dorsoventrally, elongated or not by a horned preapical process. The oval to polygonal outline is the result of a short epicyst and a long hypocyst.
Wall: Delicate, formed by an autophragm or closely appressed endophragm and periphragm.
Wall features: Surface smooth, scabrate, granulate near the bases of the ornamental reliefs and on the antapical area. The septa and/or processes are smooth, granulate or striate and perforate. The septa have smooth, denticulate or profoundly indented crests, which may be replaced by an alignment of processes, sometimes interconnected proximally.
Paratabulation: Sexiform gonyaulacoid, indicated by elevated or low (aligned granae) septa and processes which may be intratabular, penitabular and parasutural on the same cyst. According to these reliefs, the apparent paratabulation is formed by 0-?2 preapical(s), 4 apicals, ?1 anterior intercalary, 6 precingulars, X cingulars, 5 postcingulars, 1 antapical, ?1 postintercalary, X sulcals. The precingular paraplate 4 and postcingular IV are superimposed and middorsal. The preapical paraplate(s) P and Q? may form a horned process. The apical paraplates may or may not bear processes. On the precingular paraplates, the reliefs are penitabular, with adcingular interruptions. The paracingulum is sagging. The postcingular paraplates and antapical Y are delimited by parasutral reliefs. Only four postcingular parasutures are ornamented: II/III, III/IV, IV/V and V/VI. The antapical paraplate Y has a symmetrical arrangement in dorsoventral compression. Its centre is situated on the axis of the cyst. It may bear a distally bifid process.
Archaeopyle: Apical, type (tA)a. The accessory precingular sutures of the archaeopyle may be well-developed. The operculum, composite and adnate, remains attached at the precingular paraplates 1i and 2 and sulcal ai.
Paracingulum: Sagging, indicated by a septum or intratabular processes. The "single" septum has two distal lips.
Parasulcus: Oriented longitudinally, probably type L? (Evitt, 1985). The sulcal paraplates and the sutures between the sulcus and adjacent paraplates (2, 1i, X, II and VI) are not expressed by the reliefs.
Dimensions: Variable, 60-100 µm long.
Affinities:
Magrebinia differs from Dinopterygium in its apical archaeopyle and adnate operculum. Dinopterygium has a combination archaeopyle and the composite operculum is free. The morphology of Magrebinia is comparable to that of Atopodinium Drugg, 1978. The archaeopyle is apical in both genera. The operculum is free in Atopodinium, adnate in Maghrebinia. At the present state of knowledge, the paratabulation of the genus Atopodinium ( 1`, 5``, Xc, 5```, 1````) is different from that of Maghrebinia.
[Maghrebinia, Below, 1981a, p. 22; Emendation: Masure, 1988a, p. 362–363.
Type species: originally as Dinopterygium perforatum, Clarke and Verdier, 1967 (pl.6, figs.1–2)] ; Maghrebinia perforata, emend. Below, 1981; emend. Masure, 1988
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Below, 1981]: (Translation: Stover and Williams, 1987, p. 154):
Diagnosis:
Cysts are acavate, chorate to proximochorate, lenticular, two-layered, with spheroidal to hexagonal outlines. Paratabulation determined as 4`, 4``, Oc, 4``,1````, 0s. Additional precingular and postcingular paraplates possibly integrated within the broad,undifferentiated ventral sulcal zone. Paracingulum not subdivided, marked by a single, high, often incised membrane, which is also parasutural. Intersections of parasutural membranes are often reinforced. With the exception of the supported gonal lists, partial and complete reduction of the septa is possible. Archeopyle apical type A.
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Modified description:
Stover and Williams, 1987, p. 153:
Synopsis:
Cysts proximochorate to skolochorate, lenticular; body with continuous or discontinuous parasutural septa or processes; some of the latter are gonal whereas the apical processes appear to be intratabular; paratabulation indicated by parasutural features and presumably intratabular processes, formula: 3`-?4`, 4-5``, Xc, 4```,1``````; archeopyle apical, type [tA], operculum free.
Description:
Shape: Body lenticular, outline subcircular to elliptical; septate forms may have a somewhat hexagonal outline.
Wall relationships: Wall layers appressed except where septa or processes are formed.
Wall features: Parasutural features consist of continuous or discontinuous septa, together with simple and branched processes which may be isolated or connected distally. Processes in the apical area apparently intratabular; surface features and/ or wall layers smooth, or perforate. Mid-dorsal and mid-ventral areas more or less without septa or processes.
Archeopyle: Apical, type [tA]; trace of principal archeopyle suture unknown.
Paratabulation: Indicated by parasutural features and presumably intratabular processes in the apical area; formula: 3-?4`, 4-5", Xc, 4"`,1"".
Paracingulum: Expressed by single transverse septum or by equatorial processes, of which some are clearly wider than others.
Parasulcus: Apparently lies within broad, undifferentiated ventral area free of septa and processes.
Size: Intermediate; width including processes and septa, about 65 µm to nearly 100 µm.
Affinities:
Maghrebinia is similar to Cyclonephelium Deflandre and Cookson 1955 emended Stover and Evitt 1978 in having a lenticular body and relatively large medial, process-free areas on the dorsal and ventral surfaces. Cyclonephelium does not have 3 or 4 isolated processes within the apical area as on Maghrebinia, however, and the outline of the archeopyle in Cyclonephelium clearly indicates the presence of 6 precingular paraplates. Because the shape of the archeopyle is unknown and more precise information about the paratabulation of Maghrebinia is not available, no additional comparative remark is offered.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Masure, 1988: (Translation: Fensome et al., 1991, p. 340-341, LPP (affinities)):
Diagnosis:
Acavate dinoflagellate cyst, chorate to proximate, subspherical, in outline polugonal to oval. Wall formed by autophragm or by closely appressed endophragm and periphragm, outer surface smooth to granulate. Paratabulation sexiform gonyaulacoid, reflected by septa and/or intratabular, penitabular and parasutural processes. Ventral area not tabulated by the reliefs, undifferentiated. Archaeopyle apical, type (tA)a, with accessory precingular sutures. Operculum composite adnate.
Description:
Shape: Subspherical cyst, slightly compressed dorsoventrally, elongated or not by a horned preapical process. The oval to polygonal outline is the result of a short epicyst and a long hypocyst.
Wall: Delicate, formed by an autophragm or closely appressed endophragm and periphragm.
Wall features: Surface smooth, scabrate, granulate near the bases of the ornamental reliefs and on the antapical area. The septa and/or processes are smooth, granulate or striate and perforate. The septa have smooth, denticulate or profoundly indented crests, which may be replaced by an alignment of processes, sometimes interconnected proximally.
Paratabulation: Sexiform gonyaulacoid, indicated by elevated or low (aligned granae) septa and processes which may be intratabular, penitabular and parasutural on the same cyst. According to these reliefs, the apparent paratabulation is formed by 0-?2 preapical(s), 4 apicals, ?1 anterior intercalary, 6 precingulars, X cingulars, 5 postcingulars, 1 antapical, ?1 postintercalary, X sulcals. The precingular paraplate 4 and postcingular IV are superimposed and middorsal. The preapical paraplate(s) P and Q? may form a horned process. The apical paraplates may or may not bear processes. On the precingular paraplates, the reliefs are penitabular, with adcingular interruptions. The paracingulum is sagging. The postcingular paraplates and antapical Y are delimited by parasutral reliefs. Only four postcingular parasutures are ornamented: II/III, III/IV, IV/V and V/VI. The antapical paraplate Y has a symmetrical arrangement in dorsoventral compression. Its centre is situated on the axis of the cyst. It may bear a distally bifid process.
Archaeopyle: Apical, type (tA)a. The accessory precingular sutures of the archaeopyle may be well-developed. The operculum, composite and adnate, remains attached at the precingular paraplates 1i and 2 and sulcal ai.
Paracingulum: Sagging, indicated by a septum or intratabular processes. The "single" septum has two distal lips.
Parasulcus: Oriented longitudinally, probably type L? (Evitt, 1985). The sulcal paraplates and the sutures between the sulcus and adjacent paraplates (2, 1i, X, II and VI) are not expressed by the reliefs.
Dimensions: Variable, 60-100 µm long.
Affinities:
Magrebinia differs from Dinopterygium in its apical archaeopyle and adnate operculum. Dinopterygium has a combination archaeopyle and the composite operculum is free. The morphology of Magrebinia is comparable to that of Atopodinium Drugg, 1978. The archaeopyle is apical in both genera. The operculum is free in Atopodinium, adnate in Maghrebinia. At the present state of knowledge, the paratabulation of the genus Atopodinium ( 1`, 5``, Xc, 5```, 1````) is different from that of Maghrebinia.