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Corculodinium
From Williams et al., 2017:
[Corculodinium, Batten and Lister, 1988, p. 350; Emendation: Courtinat, 2000, p.172.
Type species: Corculodinium uniconicum, Batten and Lister, 1988 (figs.3h–i)]
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Original description: [Batten and Lister, 1988]:
Diagnosis:
Small, proximate, heart-shaped cyst; epicyst without apical horn or prominence, usually slightly indented at apex when undehisced, broader than hypocyst which is typically conical. Phragma thin, consisting of two closely adpressed layers, sometimes with a minute antapical pericoel, but periphragm may not be developed in some specimens; when present it is laevigate and endophragm is scabrate to minutely granulate. Paratabulation either indiscernible or partly indicated by archeopyle development and sometimes by crumpling of periphragm, interpreted as peridiniacean. Archeopyle, combination apicalintercalary (tAtI), formed by partial dehiscence of simple operculum which is adnate ventrally, sometimes enlarged by secondary splitting at aperture margin along accessory sutures between some precingular paraplates.
Affinities:
Although the peridiniacean affinity of the type species is evident in some specimens, its diminutive size, the lack of well-developed cavation or apparent absence of a periphragm, the indented apex and conical hypocyst serve to distinguish it from the majority of two-layered peridinioid genera. The most closely comparable genus is Ascodinium Cookson and Eisenack, 1960 emend. Helenes, 1984 which is, however, much larger and usually has a relatively conspicuous pericoel. Species referred to this genus are also either circumcavate or cornucavate with an apical and two antapical pericystal horns, the left more prominent than the right, and the endocyst is commonly ovoid or spherical. The morphology of C. uniconicum is sufficiently different from these to merit its designation as the type species of a new genus.
[Corculodinium, Batten and Lister, 1988, p. 350; Emendation: Courtinat, 2000, p.172.
Type species: Corculodinium uniconicum, Batten and Lister, 1988 (figs.3h–i)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Batten and Lister, 1988]:
Diagnosis:
Small, proximate, heart-shaped cyst; epicyst without apical horn or prominence, usually slightly indented at apex when undehisced, broader than hypocyst which is typically conical. Phragma thin, consisting of two closely adpressed layers, sometimes with a minute antapical pericoel, but periphragm may not be developed in some specimens; when present it is laevigate and endophragm is scabrate to minutely granulate. Paratabulation either indiscernible or partly indicated by archeopyle development and sometimes by crumpling of periphragm, interpreted as peridiniacean. Archeopyle, combination apicalintercalary (tAtI), formed by partial dehiscence of simple operculum which is adnate ventrally, sometimes enlarged by secondary splitting at aperture margin along accessory sutures between some precingular paraplates.
Affinities:
Although the peridiniacean affinity of the type species is evident in some specimens, its diminutive size, the lack of well-developed cavation or apparent absence of a periphragm, the indented apex and conical hypocyst serve to distinguish it from the majority of two-layered peridinioid genera. The most closely comparable genus is Ascodinium Cookson and Eisenack, 1960 emend. Helenes, 1984 which is, however, much larger and usually has a relatively conspicuous pericoel. Species referred to this genus are also either circumcavate or cornucavate with an apical and two antapical pericystal horns, the left more prominent than the right, and the endocyst is commonly ovoid or spherical. The morphology of C. uniconicum is sufficiently different from these to merit its designation as the type species of a new genus.