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Hapsidaulax
From Williams et al., 2017:
[Hapsidaulax, Sarjeant, 1975b, p. 143-144
Type species: Hapsidaulax margarethae, Sarjeant, 1975b (pl.1, figs.c–d; text-figs.1A–D)] ; emend. Stancliffe and Sarjeant, 1990
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Original description: [Sarjeant, 1975]:
Diagnosis:
Proximochorate to proximate dinoflagellate cysts. Overall shape spheroidal to ovoidal or subpolygonal, with or without a slight apical prominence but without a true apical horn and wholly lacking median or precingular horns. Central body ellipsoidal to spheroidal or broadly ovoidal in shape, with or without an apical prominence.
Reflected tabulation 5`, 1-2a, 7``, 0c, 6```, 1p, 0-1pv, 1````; one or more sulcal plateareas are present, one or more pre-apical plates may also be present. Tabulation outlined by trabeculace supported by gonal and sutural processes; crests may link the trabeculae with the surface of the central body or may be partly or wholly leaking. (The pattern of trabeculae and the degree of development of crests varies, not only between individuals but even on a single individual cyst.) No indication of a cingulum, the trabeculae bounding the precingular plate-areas posteriorly also bounding the postcingular plate areas anteriorly. Mode of archaeopyle formation not established with certainty, but probably by loss of the third precingular plate-area.
Affinities:
Heslertonia and Egmontodinium have high crests but exhibit a more complex tabulation pattern. Adnatosphaeridium has a much more elaborate meshwork of trabeculae whose tabulation pattern has not yet been determined, if indeed it is determinable. The plate-areas of Polystephanephorus, Taeniophora, Systematophora and Epiplosphaera are essentially intratabular rather than gonal or sutural and are not consistently linked one to another. Moreover, all these last five genera have apical archaeopyles, whereas the archaeopyle of Hapsidaulax appears to be developed by the throwing-off of a single precingular plate-area and is quite certainly not apical.
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Modified description:
Stover and Evitt, 1978, p. 232:
Synopsis:
Cysts proximochorate; body subspherical to ellipsoidal and surrounded by a network (ectophragm) of single parasutural trabeculae supported by gonal and intergonal processes; trabeculae without gonal or intergonal branches; paratabulation indicated by parasutural features, formula: 5`, 1-2a, 7", 0c, 6```, 1p, 1````; archeopyle not observed.
Description:
Shape: Body subspherical to ellipsoidal; surrounding trabecular network more or less concentric to body.
Wall relationships: Autophragm surrounded by an ectophragmal network of single parasutural trabeculae supported by gonal and intergonal processes.
Wall features: Parasutural trabeculae form large-mesh ectophragmal network; trabeculae vary in width and supporting processes vary in width and height: both are smooth, striate or perforate; autophragm thin.
Paratabulation: Indicated by parasutural trabeculae and supporting processes; formula: 5`,1-2a, 7", 0c, 6```,1p, 1````; parasulcal and preapical paraplates may be indicated.
Archeopyle: Not observed.
Paracingulum: Not expressed, per se; precingular and postcingular paraplates are adjacent and are separated by a series of transverse
trabeculae.
Parasulcus: Confined mainly to hypocyst and may be subdivided.
Size: Small to intermediate.
Affinities:
Hapsidaulax differs from Cannosphaeropsis in lacking small branches along the trabeculae and Spiniferites-type processes, and in having a paratabulation formula that is not gonyaulacacean.
[Hapsidaulax, Sarjeant, 1975b, p. 143-144
Type species: Hapsidaulax margarethae, Sarjeant, 1975b (pl.1, figs.c–d; text-figs.1A–D)] ; emend. Stancliffe and Sarjeant, 1990
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Sarjeant, 1975]:
Diagnosis:
Proximochorate to proximate dinoflagellate cysts. Overall shape spheroidal to ovoidal or subpolygonal, with or without a slight apical prominence but without a true apical horn and wholly lacking median or precingular horns. Central body ellipsoidal to spheroidal or broadly ovoidal in shape, with or without an apical prominence.
Reflected tabulation 5`, 1-2a, 7``, 0c, 6```, 1p, 0-1pv, 1````; one or more sulcal plateareas are present, one or more pre-apical plates may also be present. Tabulation outlined by trabeculace supported by gonal and sutural processes; crests may link the trabeculae with the surface of the central body or may be partly or wholly leaking. (The pattern of trabeculae and the degree of development of crests varies, not only between individuals but even on a single individual cyst.) No indication of a cingulum, the trabeculae bounding the precingular plate-areas posteriorly also bounding the postcingular plate areas anteriorly. Mode of archaeopyle formation not established with certainty, but probably by loss of the third precingular plate-area.
Affinities:
Heslertonia and Egmontodinium have high crests but exhibit a more complex tabulation pattern. Adnatosphaeridium has a much more elaborate meshwork of trabeculae whose tabulation pattern has not yet been determined, if indeed it is determinable. The plate-areas of Polystephanephorus, Taeniophora, Systematophora and Epiplosphaera are essentially intratabular rather than gonal or sutural and are not consistently linked one to another. Moreover, all these last five genera have apical archaeopyles, whereas the archaeopyle of Hapsidaulax appears to be developed by the throwing-off of a single precingular plate-area and is quite certainly not apical.
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Modified description:
Stover and Evitt, 1978, p. 232:
Synopsis:
Cysts proximochorate; body subspherical to ellipsoidal and surrounded by a network (ectophragm) of single parasutural trabeculae supported by gonal and intergonal processes; trabeculae without gonal or intergonal branches; paratabulation indicated by parasutural features, formula: 5`, 1-2a, 7", 0c, 6```, 1p, 1````; archeopyle not observed.
Description:
Shape: Body subspherical to ellipsoidal; surrounding trabecular network more or less concentric to body.
Wall relationships: Autophragm surrounded by an ectophragmal network of single parasutural trabeculae supported by gonal and intergonal processes.
Wall features: Parasutural trabeculae form large-mesh ectophragmal network; trabeculae vary in width and supporting processes vary in width and height: both are smooth, striate or perforate; autophragm thin.
Paratabulation: Indicated by parasutural trabeculae and supporting processes; formula: 5`,1-2a, 7", 0c, 6```,1p, 1````; parasulcal and preapical paraplates may be indicated.
Archeopyle: Not observed.
Paracingulum: Not expressed, per se; precingular and postcingular paraplates are adjacent and are separated by a series of transverse
trabeculae.
Parasulcus: Confined mainly to hypocyst and may be subdivided.
Size: Small to intermediate.
Affinities:
Hapsidaulax differs from Cannosphaeropsis in lacking small branches along the trabeculae and Spiniferites-type processes, and in having a paratabulation formula that is not gonyaulacacean.