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Walvisia
From Williams et al., 2017:
[Walvisia, Miles, 1990, p.82–84.
Type species: Walvisia woodii, Miles, 1990 (pl.2, figs.1–3)]
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Original description: [Miles, 1990]:
Diagnosis:
Chorate dinoflagellate cysts with an ovoidal to spheroidal main body and an apical horn. The cyst wall is two-layered, with a psilate endophragm and a fibro-reticulate periphragm.
The processes are complex and variable each comprising numerous fibrous elements that are intricately interlinked. The fibrous elements radiate out onto the cyst surface, where they ramify and interconnect with fibers from adjacent processes, forming the strongly fibro-reticulate periphragm. The distribution of the processes reflects a typical gonyaulacoid tabulation formula (Taylor/Evitt notation in parentheses): x pr, 4` (A-C, lu), 6" (li, 2-6), 6c (au, b-e, fi), 6``` (Iu, II-VI), lp (X), I```` (Y), Ss (ai, fu, li, Im, Z). The processes are paraplate-centered, with one process per plate, with the exception of the cingular series. The cingular paraplates are represented by pairs of simple processes. The sulcal arrangement conforms to the L-type sexiform group of Evitt (1985).
A two-plate precingular archeopyle is formed by the loss of paraplates 2" and 3". Operculum not observed.
Remark:
The characteristic features of this genus are the two-plate precingular archeopyle, the strongly fibro-reticulate periphragm, the fibrous processes that reflect a gonyaulacoid tabulation formula, and the apical horn.
[Walvisia, Miles, 1990, p.82–84.
Type species: Walvisia woodii, Miles, 1990 (pl.2, figs.1–3)]
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Original description: [Miles, 1990]:
Diagnosis:
Chorate dinoflagellate cysts with an ovoidal to spheroidal main body and an apical horn. The cyst wall is two-layered, with a psilate endophragm and a fibro-reticulate periphragm.
The processes are complex and variable each comprising numerous fibrous elements that are intricately interlinked. The fibrous elements radiate out onto the cyst surface, where they ramify and interconnect with fibers from adjacent processes, forming the strongly fibro-reticulate periphragm. The distribution of the processes reflects a typical gonyaulacoid tabulation formula (Taylor/Evitt notation in parentheses): x pr, 4` (A-C, lu), 6" (li, 2-6), 6c (au, b-e, fi), 6``` (Iu, II-VI), lp (X), I```` (Y), Ss (ai, fu, li, Im, Z). The processes are paraplate-centered, with one process per plate, with the exception of the cingular series. The cingular paraplates are represented by pairs of simple processes. The sulcal arrangement conforms to the L-type sexiform group of Evitt (1985).
A two-plate precingular archeopyle is formed by the loss of paraplates 2" and 3". Operculum not observed.
Remark:
The characteristic features of this genus are the two-plate precingular archeopyle, the strongly fibro-reticulate periphragm, the fibrous processes that reflect a gonyaulacoid tabulation formula, and the apical horn.