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Lagenorhytis
From Williams et al., 2017:
[Lagenorhytis, Duxbury, 1979b, p. 587; Emendation: Piasecki, 1984, p. 149
Substitute name for Speetonia, Duxbury, 1977, p.48–49 (an illegitimate name)
Type species: originally as Speetonia delicatula, Duxbury, 1977 (pl.12, fig.4)] ; Lagenorhytis delicatula, Duxbury 1979; emend. Piasecki 1984
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Original description Speetonia: [Duxbury, 1977]:
Description:
Spheroidal to ovoidal cysts with a strong apical horn which is distally closed. No indication of tabulation except for a large, two-plate precingular archeopyle.
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Emended description Lagenorhytis:
Piasecki, 1984:
Description:
Proximate, spheroidal to ovoidal dinoflagellate cysts with a two-plate precingular archaeopyle, presumably 3" and 4". The operculum is compound of two plates, the one (4") often remaining attached. No cingulum, sulcus or tabulation are reflected by the morphology apart from the shape of the archaeopyle. The cyst wall is single layered (autophragm) and unstructured. If present, surface sculpture is low. A hollow apical protuberance or horn may be present.
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Modified description:
Stover and Williams, 1987, p. 143:
Synopsis:
Cysts proximate, autophragm subspherical to ovoidal with a hollow apical protuberance or horn; surface ornamented with features of low relief; archeopyle type 2P, presumably 3" and 4", opercular pieces free or adnate posteriorly.
Description:
Shape: Body subspherical to ovoidal with a hollow apical horn or low protuberance.
Wall relationships: Autophragm only.
Wall features: No features indicating paratabulation except for archeopyle. Wall smooth or ornamented with features of low relief.
Archeopyle: Type 2P; released paraplates are presumably 3"+4"; opercular pieces free or 4" may be adnate posteriorly.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Intermediate to large; length about 75 to 120 µm.
Affinities:
Lagenorhytis differs from Apteodinium Eisenack 1958 and Komewuia Cookson and Eisenack 1960b emended Chen 1982 in having a 2P archeopyle rather than a simple P archeopyle. Both Bitectatodinium Wilson 1973 and Gongylodinium Fensome et al. 1980, which also possess 2P archeopyles, have more complexly structured walls than Lagenorhytis.
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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.
Lagenorhytis Duxbury, 1979b. Synopsis from Stover and Williams (1987, p.143). Cysts proximate, autophragm subspherical to ovoidal with a hollow apical protuberance or horn; surface ornamented with features of low relief; archeopyle type 2P, presumably 3" and 4", opercular pieces free or adnate posteriorly.
[Lagenorhytis, Duxbury, 1979b, p. 587; Emendation: Piasecki, 1984, p. 149
Substitute name for Speetonia, Duxbury, 1977, p.48–49 (an illegitimate name)
Type species: originally as Speetonia delicatula, Duxbury, 1977 (pl.12, fig.4)] ; Lagenorhytis delicatula, Duxbury 1979; emend. Piasecki 1984
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description Speetonia: [Duxbury, 1977]:
Description:
Spheroidal to ovoidal cysts with a strong apical horn which is distally closed. No indication of tabulation except for a large, two-plate precingular archeopyle.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description Lagenorhytis:
Piasecki, 1984:
Description:
Proximate, spheroidal to ovoidal dinoflagellate cysts with a two-plate precingular archaeopyle, presumably 3" and 4". The operculum is compound of two plates, the one (4") often remaining attached. No cingulum, sulcus or tabulation are reflected by the morphology apart from the shape of the archaeopyle. The cyst wall is single layered (autophragm) and unstructured. If present, surface sculpture is low. A hollow apical protuberance or horn may be present.
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Modified description:
Stover and Williams, 1987, p. 143:
Synopsis:
Cysts proximate, autophragm subspherical to ovoidal with a hollow apical protuberance or horn; surface ornamented with features of low relief; archeopyle type 2P, presumably 3" and 4", opercular pieces free or adnate posteriorly.
Description:
Shape: Body subspherical to ovoidal with a hollow apical horn or low protuberance.
Wall relationships: Autophragm only.
Wall features: No features indicating paratabulation except for archeopyle. Wall smooth or ornamented with features of low relief.
Archeopyle: Type 2P; released paraplates are presumably 3"+4"; opercular pieces free or 4" may be adnate posteriorly.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Intermediate to large; length about 75 to 120 µm.
Affinities:
Lagenorhytis differs from Apteodinium Eisenack 1958 and Komewuia Cookson and Eisenack 1960b emended Chen 1982 in having a 2P archeopyle rather than a simple P archeopyle. Both Bitectatodinium Wilson 1973 and Gongylodinium Fensome et al. 1980, which also possess 2P archeopyles, have more complexly structured walls than Lagenorhytis.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Lagenorhytis Duxbury, 1979b. Synopsis from Stover and Williams (1987, p.143). Cysts proximate, autophragm subspherical to ovoidal with a hollow apical protuberance or horn; surface ornamented with features of low relief; archeopyle type 2P, presumably 3" and 4", opercular pieces free or adnate posteriorly.