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Palaeohystrichophora
From Fensome et al., 2019:
Palaeohystrichophora, Deflandre, 1935, p.230.
Emendations: Deflandre and Cookson, 1955, p.257; Santos et al., 2018, p.167. This genus was not validly published in Deflandre (1934, caption to fig.8 -- p.967) since no description was provided.
Type: Deflandre, 1935, pl.8, fig.4, as Palaeohystrichophora infusorioides.
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Original description: [Deflandre, 1935]:
Diagnosis: (after the lengthy description of Deflandre, 1936 translated by Stover and Evitt, 1978, p. 234):
This genus has been created for an organism whose cell is covered with flexible hairs, becoming more tenuous towards the apex; a double series of these hairs borders the edges of a slightly depressed transverse furrow.
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Emended description:
Deflandre and Cookson, 1955:
Description:
Dinoflagellates with a generally thin theca furnished with a transverse girdle, longitudinal furrow clear or indistinct, plates absent, membrane covered with irregularly disposed, stiff or soft spines or hairs.
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Modified descriptions:
Stover and Evitt 1978, p. 234-235:
Synopsis:
Cysts bicavate, pericyst biconical to compressed peridinoid, endocyst subspherical to ellipsoidal; apical and antapical pericoels present; periphragm with short to long hairlike processes; paracingulum usually clearly delimited; no archeopyle.
Description:
Shape: Pericyst biconical to compressed peridinoid.
Wall relationships: Bicavate, subsphaerical to ellipsoidal; endocyst separated from pericyst apically and antapically, appressed elsewhere; pericoel usually prominent.
Wall features: Low parasutural ridges generally indicate the margins of the paracingulum. Periphragm bears few to numerous short to long hairlike processes, of which some are aligned along the parasutural ridges delimiting the paracingulum. Other processes are distributed randomly or discontinuous lines not clearly parasutural.
Paratabulation: Indications absent, except for paracingulum.
Archeopyle: Absent.
Paracingulum: Indicated by low parallel, transverse ridges surmounted with processes.
Parasulcus: Not indicated, or poorly expressed as a folded and apparently depressed area on the hypocyst.
Size: Small to intermediate.
Affinities:
Palaeohystrichophora differs from Subtilisphaera, which also lacks an archeopyle, in having hairlike processes and in being generally more elongate.
Palaeohystrichophora, Deflandre, 1935, p.230.
Emendations: Deflandre and Cookson, 1955, p.257; Santos et al., 2018, p.167. This genus was not validly published in Deflandre (1934, caption to fig.8 -- p.967) since no description was provided.
Type: Deflandre, 1935, pl.8, fig.4, as Palaeohystrichophora infusorioides.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Deflandre, 1935]:
Diagnosis: (after the lengthy description of Deflandre, 1936 translated by Stover and Evitt, 1978, p. 234):
This genus has been created for an organism whose cell is covered with flexible hairs, becoming more tenuous towards the apex; a double series of these hairs borders the edges of a slightly depressed transverse furrow.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Deflandre and Cookson, 1955:
Description:
Dinoflagellates with a generally thin theca furnished with a transverse girdle, longitudinal furrow clear or indistinct, plates absent, membrane covered with irregularly disposed, stiff or soft spines or hairs.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified descriptions:
Stover and Evitt 1978, p. 234-235:
Synopsis:
Cysts bicavate, pericyst biconical to compressed peridinoid, endocyst subspherical to ellipsoidal; apical and antapical pericoels present; periphragm with short to long hairlike processes; paracingulum usually clearly delimited; no archeopyle.
Description:
Shape: Pericyst biconical to compressed peridinoid.
Wall relationships: Bicavate, subsphaerical to ellipsoidal; endocyst separated from pericyst apically and antapically, appressed elsewhere; pericoel usually prominent.
Wall features: Low parasutural ridges generally indicate the margins of the paracingulum. Periphragm bears few to numerous short to long hairlike processes, of which some are aligned along the parasutural ridges delimiting the paracingulum. Other processes are distributed randomly or discontinuous lines not clearly parasutural.
Paratabulation: Indications absent, except for paracingulum.
Archeopyle: Absent.
Paracingulum: Indicated by low parallel, transverse ridges surmounted with processes.
Parasulcus: Not indicated, or poorly expressed as a folded and apparently depressed area on the hypocyst.
Size: Small to intermediate.
Affinities:
Palaeohystrichophora differs from Subtilisphaera, which also lacks an archeopyle, in having hairlike processes and in being generally more elongate.