Back
Lejeunia
From Fensome et al., 2019:
"Lejeunia", Gerlach, 1961, p.169.
Emendations: Kjellström, 1972, p.467, Lentin and Williams, 1976, p.68–69 and Bujak in Bujak et al., 1980, p.68, all as Lejeunia -- however, see Head (1993, p.30–31). Name illegitimate -- senior homonym: Lejeunea Libert, 1820. Substitute name: Lejeunecysta. Originally Lejeunia Gerlach, 1961 (generic name illegitimate), subsequently (and now) Lejeunecysta, thirdly Protoperidinium subgenus Protoperidinium section Lejeunecysta (section name not validly published).
Taxonomic senior synonym: Quinquecuspis, by implication in Matsuoka (1987, p.57), who incorrectly considered Lejeunecysta to be the senior
name -- however, this synonymy has not been generally followed.
Type: Gerlach, 1961, pl.26, figs.10–11, as Lejeunia hyalina.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Lejeunia: [Gerlach, 1961]: (Translation: Stover and Evitt, 1978, p. 111):
Diagnosis:
Theca bilaterally symmetrical-polygonal, with apical horn and two antapical horns; without tabulation. Course of transverse furrow spiral, longitudinal furrow suggested.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description as Lejeunia:
Kjellström, 1972:
Description:
Proximate dinoflagellate cysts pentagonal in shape, more or less well defined apical horn and two antapical horns. Cingulum present or absent. Sulcus weakly defined or absent. No tabulation. Archaeopyle precingular.
---------------------------------------
Lentin and Williams, 1976:
Diagnosis:
Pericyst: Ambitus rhomboidal to peridinioid, pentagonal, usually elongated in an anterio-posterior direction. Apex rounded or prolonged into an apical horn of variable length which usually merges imperceptibly with the anterior epipericyst. Antapex with two unequal symmetrically located antapical lobes separated by a concavity, or with two more or less equal symmetrically located antapical horns. These usually merge imperceptibly with the posterior hypopericyst. The right antapical horn is sometimes reduced. Epipericyst and hypopericyst of more or less equal size. Length to breadth ratio generally >1. Compression dorso-ventral, often extreme.
Endocyst: Not always observable. In some taxa appears to be appressed to pericyst throughout.
Pericoels: May be present as small cavities at the tips of the apical and antapical horns.
Phragma: Usually of constant thickness and rarely separable into periphragm and endophragm. Surface laevigate or striate.
Pericyst: Paratabulation indeterminate other than in the vicinity of the archaeopyle.
Pericingulum: Present or absent. When present may be delineated by folding, by one parasuture only, or by anterior and posterior parasutures. The parasutures may be raised with entire or denticulate margins. Commonly indented. Planar or helicoidal.
Perisulcus: Extending onto epipericyst but considerably larger on the hypopericyst. Widening posteriorly.
Endocyst: Paratabulation indeterminate.
Archaeopyle: When observable standard hexa resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. This paraplate extends almost to the pericingulum in several specimens. Operculum free or remaining attached along parasuture H4. Since the endophragm and periphragm are appressed in the vicinity of the archaeopyle, there is no separation of the endoperculum and perioperculum so that effectively there is one archaeopyle and one operculum. Transverse archaeopyle index is 0.36-0.47. Transverse archaeopyle ratio is 0.58-0.88.
Archaeopyle Formula: I/I (2a/2a).
---------------------------------------
Stover and Evitt, 1978:
Synopsis:
Cysts proximate, roundly pentagonal to compressed peridinioid, typically with a short apical and two antapical projections or horns; autophragm smooth or with scattered, normally isolated features of low relief; paratabulation indicated by archeopyle and paracingulum, either together or separately; archeopyle, when discernible, intercalary, Type I; archeopyle index 0.3 to 0.4.
Description:
Shape: Roundly pentagonal to peridinioid, with a single short apical and two antapical protrusions or horns.
Wall relationships: Autophragm only.
Wall features: No parasutural features. Autophragm smooth or with scattered features of low relief; ornamentation may show indications of alignment or be concentrated in specific areas.
Paratabulation: Generally indicated by archeopyle and paracingulum, either together or separately.
Archeopyle: Intercalary, Type I (2a only); archeopyle index 0.3 to 0.4; operculum free. Archeopyle not always discernible; specimens in which the archeopyle is visible, and others in which it is not, occur together. Antapical margin of archeopyle is near the paracingulum and commonly appears as a precingular rather than an intercalary archeopyle.
Paracingulum: Not indicated, or indicated at the widest part of the cyst by one or more of the following: (1) poorly to sharply delimited transverse folds or ridges, (2) transverse row of denticles, (3) slight convexities or concavities at lateral margins.
Parasulcus: Not indicated, or indicated only by slight longitudinal concavity, usually confined to hypocyst.
Size: Intermediate to large.
Affinities:
Lejeunia differs from Morkallacysta in that it lacks well-developed apical and antapical horns. It differs from Phelodinium in having an autophragm and convex rather than straight or slightly concave sides. In addition, the horns on most species of Phelodinium are considerably longer than those on Lejeunia.
---------------------------------------
Bujak in Bujak et al., 1980:
Diagnosis:
Autocyst peridinioid with dorsoventral compression and a pentagonal ambitus. The epicyst and hypocyst lengths are approximately equal. The apex is rounded or prolonged into a small distinct boss. The antapex has two approximately equal, symmetrically located horns which are small, pointed, and solid. Autophragm laevigate to chagrinate. Paratabulation is only indicated near the archaeopyle and paracingulum. A planar or very slightly helicoidal paracingulum is delimited by two folds and a shallow indentation. The folds are distally entire and may be continuous or partite. When partite, the paracingulum is separated into seven anterior and five posterior divisions. The parasulcus is marked by a shallow depression. The archaeopyle is intercalary 2a and is symmetrically located on the middorsal line. It extends almost to the paracingulum. The operculum is free or remains attached along the posterior margin. Transverse archaeopyle index= 0.34-0.51, longitudinal archaeopyle index= 0.59-0.63, archaeopyle ratio= 0.72-0.94.
Affinities:
The genus Lejeunia differs from Selenopemphix Benedek, 1972, in having an intercalary archaeopyle that is symmetrically located on the middorsal line.
"Lejeunia", Gerlach, 1961, p.169.
Emendations: Kjellström, 1972, p.467, Lentin and Williams, 1976, p.68–69 and Bujak in Bujak et al., 1980, p.68, all as Lejeunia -- however, see Head (1993, p.30–31). Name illegitimate -- senior homonym: Lejeunea Libert, 1820. Substitute name: Lejeunecysta. Originally Lejeunia Gerlach, 1961 (generic name illegitimate), subsequently (and now) Lejeunecysta, thirdly Protoperidinium subgenus Protoperidinium section Lejeunecysta (section name not validly published).
Taxonomic senior synonym: Quinquecuspis, by implication in Matsuoka (1987, p.57), who incorrectly considered Lejeunecysta to be the senior
name -- however, this synonymy has not been generally followed.
Type: Gerlach, 1961, pl.26, figs.10–11, as Lejeunia hyalina.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Lejeunia: [Gerlach, 1961]: (Translation: Stover and Evitt, 1978, p. 111):
Diagnosis:
Theca bilaterally symmetrical-polygonal, with apical horn and two antapical horns; without tabulation. Course of transverse furrow spiral, longitudinal furrow suggested.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description as Lejeunia:
Kjellström, 1972:
Description:
Proximate dinoflagellate cysts pentagonal in shape, more or less well defined apical horn and two antapical horns. Cingulum present or absent. Sulcus weakly defined or absent. No tabulation. Archaeopyle precingular.
---------------------------------------
Lentin and Williams, 1976:
Diagnosis:
Pericyst: Ambitus rhomboidal to peridinioid, pentagonal, usually elongated in an anterio-posterior direction. Apex rounded or prolonged into an apical horn of variable length which usually merges imperceptibly with the anterior epipericyst. Antapex with two unequal symmetrically located antapical lobes separated by a concavity, or with two more or less equal symmetrically located antapical horns. These usually merge imperceptibly with the posterior hypopericyst. The right antapical horn is sometimes reduced. Epipericyst and hypopericyst of more or less equal size. Length to breadth ratio generally >1. Compression dorso-ventral, often extreme.
Endocyst: Not always observable. In some taxa appears to be appressed to pericyst throughout.
Pericoels: May be present as small cavities at the tips of the apical and antapical horns.
Phragma: Usually of constant thickness and rarely separable into periphragm and endophragm. Surface laevigate or striate.
Pericyst: Paratabulation indeterminate other than in the vicinity of the archaeopyle.
Pericingulum: Present or absent. When present may be delineated by folding, by one parasuture only, or by anterior and posterior parasutures. The parasutures may be raised with entire or denticulate margins. Commonly indented. Planar or helicoidal.
Perisulcus: Extending onto epipericyst but considerably larger on the hypopericyst. Widening posteriorly.
Endocyst: Paratabulation indeterminate.
Archaeopyle: When observable standard hexa resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. This paraplate extends almost to the pericingulum in several specimens. Operculum free or remaining attached along parasuture H4. Since the endophragm and periphragm are appressed in the vicinity of the archaeopyle, there is no separation of the endoperculum and perioperculum so that effectively there is one archaeopyle and one operculum. Transverse archaeopyle index is 0.36-0.47. Transverse archaeopyle ratio is 0.58-0.88.
Archaeopyle Formula: I/I (2a/2a).
---------------------------------------
Stover and Evitt, 1978:
Synopsis:
Cysts proximate, roundly pentagonal to compressed peridinioid, typically with a short apical and two antapical projections or horns; autophragm smooth or with scattered, normally isolated features of low relief; paratabulation indicated by archeopyle and paracingulum, either together or separately; archeopyle, when discernible, intercalary, Type I; archeopyle index 0.3 to 0.4.
Description:
Shape: Roundly pentagonal to peridinioid, with a single short apical and two antapical protrusions or horns.
Wall relationships: Autophragm only.
Wall features: No parasutural features. Autophragm smooth or with scattered features of low relief; ornamentation may show indications of alignment or be concentrated in specific areas.
Paratabulation: Generally indicated by archeopyle and paracingulum, either together or separately.
Archeopyle: Intercalary, Type I (2a only); archeopyle index 0.3 to 0.4; operculum free. Archeopyle not always discernible; specimens in which the archeopyle is visible, and others in which it is not, occur together. Antapical margin of archeopyle is near the paracingulum and commonly appears as a precingular rather than an intercalary archeopyle.
Paracingulum: Not indicated, or indicated at the widest part of the cyst by one or more of the following: (1) poorly to sharply delimited transverse folds or ridges, (2) transverse row of denticles, (3) slight convexities or concavities at lateral margins.
Parasulcus: Not indicated, or indicated only by slight longitudinal concavity, usually confined to hypocyst.
Size: Intermediate to large.
Affinities:
Lejeunia differs from Morkallacysta in that it lacks well-developed apical and antapical horns. It differs from Phelodinium in having an autophragm and convex rather than straight or slightly concave sides. In addition, the horns on most species of Phelodinium are considerably longer than those on Lejeunia.
---------------------------------------
Bujak in Bujak et al., 1980:
Diagnosis:
Autocyst peridinioid with dorsoventral compression and a pentagonal ambitus. The epicyst and hypocyst lengths are approximately equal. The apex is rounded or prolonged into a small distinct boss. The antapex has two approximately equal, symmetrically located horns which are small, pointed, and solid. Autophragm laevigate to chagrinate. Paratabulation is only indicated near the archaeopyle and paracingulum. A planar or very slightly helicoidal paracingulum is delimited by two folds and a shallow indentation. The folds are distally entire and may be continuous or partite. When partite, the paracingulum is separated into seven anterior and five posterior divisions. The parasulcus is marked by a shallow depression. The archaeopyle is intercalary 2a and is symmetrically located on the middorsal line. It extends almost to the paracingulum. The operculum is free or remains attached along the posterior margin. Transverse archaeopyle index= 0.34-0.51, longitudinal archaeopyle index= 0.59-0.63, archaeopyle ratio= 0.72-0.94.
Affinities:
The genus Lejeunia differs from Selenopemphix Benedek, 1972, in having an intercalary archaeopyle that is symmetrically located on the middorsal line.