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Desmocysta
From Williams et al., 2017:
[Desmocysta, Duxbury, 1983, p. 43-44
Type species: Desmocysta plekta, Duxbury, 1983 (pl.8, fig.11; text-fig.20D)]
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Original description: [Duxbury, 1983]:
Diagnosis:
Spheroidal to ovoidal dinoflagellate cysts. Paratabulation is absent except where indicated by a two-paraplate, precingular archeopyle, whose precise paraplate equivalence may not be discerned. Long, fine filaments extend from the antapex.
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Modified description:
Stover and Williams, 1987, p. 75:
Synopsis:
Cysts subspherical to ovoidal, proximate, with antapical filaments; paratabulation not indicated except for 2P archeopyle, operculum free, plate
equivalents of opercular pieces undetermined, presumably 2"+3" or 3"+4".
Description:
Shape: Subspherical to ovoidal.
Wall relationships: Autophragm only.
Wall features: Autophragm smooth; antapical filaments extend posteriorly to form commonly entangled "rope" which terminates in an amorphous mass.
Archeopyle: Precingular, type 2P, operculum free; exact plate equivalents of opercular pieces not determined, presumably 2"+3" or 3"+4".
Paratabulation: Expressed solely by archeopyle.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small, about 35 to 50 µm in length; length of filaments from 0.5 to approximately 1.5 times the body length.
Affinities:
Desmocysta differs from Ophiobolus O. Wetzel 1933 emended Evitt 1968 in having a 2P archeopyle rather than "An opening, formed by the parting in the wall .... near the end opposite the filaments" (Evitt, 1968, p. 6). Duxbury (1983, p. 43-44) expressed the opinion that the openings on some specimens of Ophiobolus .... "appear to show parasutural splits between pre-cingular paraplates". He then stated that Ophiobo/us possesses some type of apical, or at least precingular, archeopyle. Regardless of how one interprets the openings in the two genera,
Ophiobolus has an essentially polar opening, whereas in Desmocysta it is non-polar.
[Desmocysta, Duxbury, 1983, p. 43-44
Type species: Desmocysta plekta, Duxbury, 1983 (pl.8, fig.11; text-fig.20D)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Duxbury, 1983]:
Diagnosis:
Spheroidal to ovoidal dinoflagellate cysts. Paratabulation is absent except where indicated by a two-paraplate, precingular archeopyle, whose precise paraplate equivalence may not be discerned. Long, fine filaments extend from the antapex.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams, 1987, p. 75:
Synopsis:
Cysts subspherical to ovoidal, proximate, with antapical filaments; paratabulation not indicated except for 2P archeopyle, operculum free, plate
equivalents of opercular pieces undetermined, presumably 2"+3" or 3"+4".
Description:
Shape: Subspherical to ovoidal.
Wall relationships: Autophragm only.
Wall features: Autophragm smooth; antapical filaments extend posteriorly to form commonly entangled "rope" which terminates in an amorphous mass.
Archeopyle: Precingular, type 2P, operculum free; exact plate equivalents of opercular pieces not determined, presumably 2"+3" or 3"+4".
Paratabulation: Expressed solely by archeopyle.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Small, about 35 to 50 µm in length; length of filaments from 0.5 to approximately 1.5 times the body length.
Affinities:
Desmocysta differs from Ophiobolus O. Wetzel 1933 emended Evitt 1968 in having a 2P archeopyle rather than "An opening, formed by the parting in the wall .... near the end opposite the filaments" (Evitt, 1968, p. 6). Duxbury (1983, p. 43-44) expressed the opinion that the openings on some specimens of Ophiobolus .... "appear to show parasutural splits between pre-cingular paraplates". He then stated that Ophiobo/us possesses some type of apical, or at least precingular, archeopyle. Regardless of how one interprets the openings in the two genera,
Ophiobolus has an essentially polar opening, whereas in Desmocysta it is non-polar.