Back
Weiachia
From Williams et al., 2017:
[Weiachia, Feist-Burkhardt, 1995b, p.212–213
Type species: Weiachia fenestrata, Feist-Burkhardt, 1995b (pl.1, fig.9; text-fig.3)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Feist-Burkhardt, 1995b]:
Synopsis:
Proximate dinoflagellate cysts, dorso-ventrally flattened and cavate. Pericyst outline subcircular, subpentagonal to rounded triangular; endocyst outline subcircular, subpentagonal to rounded triangular, or peridinioid. Peri- and endophragm thin, psilate to scabrate. Periphragm with or without claustra or fenestrae. Endoarcheopyle intercalary, type Ia, operculum (2a) camerate, adnate to the precingular paraplates. Paratabulation generally not expressed on endocyst, except for archeopyle. Paratabulation on pericyst may be indicated by folds and/or fenestrae.
Description:
Shape: Proximate dinoflagellate cysts, dorso-ventrally flattened. Pericyst subcircular, subpentagonal to rounded triangular; endocyst subcircular, subpentagonal to rounded triangular, or peridinioid. Endo- and pericyst with more or less pronounced apex or protuberances.
Wall Relationships: Cysts two-layered, cavate.
Wall Features: Endophragm thin, psilate to scabrate. Periphragm thin, psilate to scabrate, sometimes folded, with or without claustra,which may correspond to paraplates (= fenestrae).
Archeopyle: Endoarcheopyle intercalary, type Ia, operculum (2a) camerate, adnate to the precingular paraplates. Periarcheopyle not observed. Paratabulation: Endocyst: generally indicated by archeopyle only; apex on endocyst marked by an oval ring-like structure, corresponding probably to the pop paraplate. Pericyst: may be indicated by folds in the periphragm and/or fenestrae corresponding to apical, anterior intercalary, precingular, postcingular and/or antapical paraplates.
Paracingulum: Endocingulum may be marked by folds and/or a large indentation of the cyst. Pericingulum may be marked by folds.
Parasulcus: Generally not indicated, flagellar pore imprint sometimes visible.
Size: Small, pericyst about 30 µm to 40 µm in maximum length.
Remarks:
The genus Weiachia is erected to accommodate cavate cysts with an Ia (2a) archeopyle type.
Affinities/Comparison:
The genus Weiachia differs from the genus Moesiodinium Antonescu 1974 emend. Below 1987 in having an intercalary archeopyle with an adnate operculum, rather than a free operculum . The genus Sirmiodiniopsis Drugg 1978 also displays large claustra in the hypocystal periphragm, but differs in having an apical archeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Weiachia Feist-Burkhardt, 1995b. This genus is cavate and has a type I archeopyle with an adnate operculum. Synopsis, from Feist-Burkhardt (1995b, p.212), proximate dinoflagellate cysts, dorso-ventrally flattened and cavate. Pericyst outline subcircular, subpentagonal to rounded triangular; endocyst outline subcircular, subpentagonal to rounded triangular, or peridinioid. Peri- and endophragm thin, psilate to scabrate; periphragm with or without claustra or fenestrae. Endoarcheopyle intercalary type I@, operculum (2a) camerate, adnate to the precingular paraplates. Paratabulation generally not expressed on endocyst, except for archeopyle. Paratabulation on pericyst may be indicated by folds and/or fenstrae.
[Weiachia, Feist-Burkhardt, 1995b, p.212–213
Type species: Weiachia fenestrata, Feist-Burkhardt, 1995b (pl.1, fig.9; text-fig.3)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Feist-Burkhardt, 1995b]:
Synopsis:
Proximate dinoflagellate cysts, dorso-ventrally flattened and cavate. Pericyst outline subcircular, subpentagonal to rounded triangular; endocyst outline subcircular, subpentagonal to rounded triangular, or peridinioid. Peri- and endophragm thin, psilate to scabrate. Periphragm with or without claustra or fenestrae. Endoarcheopyle intercalary, type Ia, operculum (2a) camerate, adnate to the precingular paraplates. Paratabulation generally not expressed on endocyst, except for archeopyle. Paratabulation on pericyst may be indicated by folds and/or fenestrae.
Description:
Shape: Proximate dinoflagellate cysts, dorso-ventrally flattened. Pericyst subcircular, subpentagonal to rounded triangular; endocyst subcircular, subpentagonal to rounded triangular, or peridinioid. Endo- and pericyst with more or less pronounced apex or protuberances.
Wall Relationships: Cysts two-layered, cavate.
Wall Features: Endophragm thin, psilate to scabrate. Periphragm thin, psilate to scabrate, sometimes folded, with or without claustra,which may correspond to paraplates (= fenestrae).
Archeopyle: Endoarcheopyle intercalary, type Ia, operculum (2a) camerate, adnate to the precingular paraplates. Periarcheopyle not observed. Paratabulation: Endocyst: generally indicated by archeopyle only; apex on endocyst marked by an oval ring-like structure, corresponding probably to the pop paraplate. Pericyst: may be indicated by folds in the periphragm and/or fenestrae corresponding to apical, anterior intercalary, precingular, postcingular and/or antapical paraplates.
Paracingulum: Endocingulum may be marked by folds and/or a large indentation of the cyst. Pericingulum may be marked by folds.
Parasulcus: Generally not indicated, flagellar pore imprint sometimes visible.
Size: Small, pericyst about 30 µm to 40 µm in maximum length.
Remarks:
The genus Weiachia is erected to accommodate cavate cysts with an Ia (2a) archeopyle type.
Affinities/Comparison:
The genus Weiachia differs from the genus Moesiodinium Antonescu 1974 emend. Below 1987 in having an intercalary archeopyle with an adnate operculum, rather than a free operculum . The genus Sirmiodiniopsis Drugg 1978 also displays large claustra in the hypocystal periphragm, but differs in having an apical archeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Weiachia Feist-Burkhardt, 1995b. This genus is cavate and has a type I archeopyle with an adnate operculum. Synopsis, from Feist-Burkhardt (1995b, p.212), proximate dinoflagellate cysts, dorso-ventrally flattened and cavate. Pericyst outline subcircular, subpentagonal to rounded triangular; endocyst outline subcircular, subpentagonal to rounded triangular, or peridinioid. Peri- and endophragm thin, psilate to scabrate; periphragm with or without claustra or fenestrae. Endoarcheopyle intercalary type I@, operculum (2a) camerate, adnate to the precingular paraplates. Paratabulation generally not expressed on endocyst, except for archeopyle. Paratabulation on pericyst may be indicated by folds and/or fenstrae.