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Wrevittia
From Williams et al., 2017:
[Wrevittia, Helenes and Lucas-Clark, 1997, p. 186-187
Type species: Gonyaulax helicoidea, Eisenack and Cookson, 1960, (pl.1, fig.4)]
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Wrevittiam Helenes and Lucas-Clark, 1997. According to Helenes and Lucas-Clark (1997, p.186-187), Wrevittia has a gonyaulacoid tabulation indicated by parasutural features. Apical horn of variable length and formed from the periphragm only. Epicyst apically cavate or cornucavate. Hypocyst suturocavate. Paratabulation includes a symmetrical-quadrate 1"", S-type sulcus with an elongate Iu and subtriangular 1i and the contacts Q/B (Q/2`), A/ai (4`/as), A/1i (4`/6"), and au/Iu (1c/1"' ). A porichnion located at the A/Q/1u triple junction. In W. cassidata, the parasutural ridges low to high, smooth, serrate or spiny, varying even within the same specimen. Intratabular features vary from smooth walls, to small granules, to spines, to numerous thick granules. Length ca 50 µm, width ca 35 µm, horn 15 µm. The genus includes W. helicoidea, W.cassidata and W. diutina. It has a cornucavate epicyst and suturocavate hypocyst. The K plate is diminutive or absent. Forms included in this genus have been described from Berriasian to Cenomanian rocks. The paratabulation pattern of this genus is commonly found in Tertiary forms and in the living species Gonyaulax spinifera .
[Wrevittia, Helenes and Lucas-Clark, 1997, p. 186-187
Type species: Gonyaulax helicoidea, Eisenack and Cookson, 1960, (pl.1, fig.4)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Wrevittiam Helenes and Lucas-Clark, 1997. According to Helenes and Lucas-Clark (1997, p.186-187), Wrevittia has a gonyaulacoid tabulation indicated by parasutural features. Apical horn of variable length and formed from the periphragm only. Epicyst apically cavate or cornucavate. Hypocyst suturocavate. Paratabulation includes a symmetrical-quadrate 1"", S-type sulcus with an elongate Iu and subtriangular 1i and the contacts Q/B (Q/2`), A/ai (4`/as), A/1i (4`/6"), and au/Iu (1c/1"' ). A porichnion located at the A/Q/1u triple junction. In W. cassidata, the parasutural ridges low to high, smooth, serrate or spiny, varying even within the same specimen. Intratabular features vary from smooth walls, to small granules, to spines, to numerous thick granules. Length ca 50 µm, width ca 35 µm, horn 15 µm. The genus includes W. helicoidea, W.cassidata and W. diutina. It has a cornucavate epicyst and suturocavate hypocyst. The K plate is diminutive or absent. Forms included in this genus have been described from Berriasian to Cenomanian rocks. The paratabulation pattern of this genus is commonly found in Tertiary forms and in the living species Gonyaulax spinifera .