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Phanerodinium
From Williams et al., 2017:
[Phanerodinium, Deflandre, 1937a, p. 110; Emendations: Below, 1987b, p. 36–38; Slimani, 1994, p. 43.
Tax. jr. syn.: Fibradinium, Microdinium, Rhiptocorys and Subtilidinium, all according to Below (1987b, p.36) — however, Lentin and Williams (1989, p.135,243,316,354) retained all four genera. Stover and Evitt (1978, p.236) noted that the type of Phanerodinium, Phanerodinium cayeuxii, is embedded in flint so the nature of the archeopyle is uncertain. Accordingly, Lentin and Williams (1989, p.289) recommended that only Phanerodinium cayeuxii and Phanerodinium setiferum be included in Phanerodinium.
Type species: Palaeoperidinium cayeuxii (name not validly published), Deflandre, 1935 (pl. 6, fig.3)]
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Original description: [Deflandre, 1937]: (Translation: Stover and Evitt, 1978, p. 236):
Diagnosis:
The theca is divided into two very unequal parts by a generally deep, circular transverse furrow. In the orientation arbitrarily adopted, the epitheca is about three times higher than the hypotheca. The transverse furrow is somewhat less high than the hypotheca. It has not yet been possible to recognize a longitudinal furrow. The epitheca is appreciably pyramidal in form, with truncated apex; however, the faces can sometimes be a little swelled, which gives the whole of the organism a somewhat less prismatic appearance. The hypotheca is pyramidal or rounded. The plates that make up the theca are well visible and clearly delineated, the hypotheca being usually less easy to examine. None of the approximately 30 specimens of P.cayeuxi encountered so far has been enabled me to count the ant-equatorial plates. These plates are connected by an apical system which compromises a large, in all probability pentagonal, plate and a small rectangular, or rather elongated trapezoidal, plate. The latter could also be considered as an intercalary plate if judged from its lateral position.
The tabulation of the hypotheca is unknown. The transverse furrow, traversed by several sutures, is composed of several plates.
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Modified description:
Stover and Evitt 1978, p. 236:
Synopsis:
Cysts proximate, compressed ellipsoidal with an obtusely angular apex; epicyst much shorter than hypocyst; paratabulation indicated by parasutural ridges; ridges with or without gonal spines; archeopyle type uncertain.
Description:
Shape: Basically compressed ellipsoidal with an obtusely angular apex; antapex rounded or truncated. Epicyst much shorter than hypocyst.
Wall relationships: Autophragm only.
Wall features: Parasutural ridges usually clearly discernible on hypocyst, and generally less well expressed to indistinct on epicyst; ridges low, smooth or denticulate, and may be surmounted with slender acuminate gonal spines.
Paratabulation: Indicated mainly on the hypocyst by parasutural features; probably gonyaulacacean, formula: ?`, ?``, x-5c(6c), 4-6```, 1p, 1````. Usually only four postcingular paraplates are delimited completely, and these are interpreted as representing plates 2``` to 5```.
Archeopyle: Type uncertain; may be a triangular opening on the dorsal surface of the epicyst immediately above the paracingulum and to the right of the midline.
Paracingulum: Indicated by parallel, transverse, parasutural ridges, with or without connecting longitudinal ridges.
Parasulcus: Generally not indicated; the antapical position of the parasulcus may be inferred by a medial declivity in the parasutural ridge above paraplate 1````.
Size: Small.
Affinities:
Phanerodinium differs from Glyphanodinium in that some forms have serrate crests and gonal spines. Lack of precise information about the paratabulation on the epicyst and the archeopyle type in Phanerodinium precludes a more detailed comparison.
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Emended descriptions:
Below, 1987: (Translation: after Translation Bureau of the Secretary of State, Canada. p. 98-99)
Diagnosis:
Arrangement of vesicles/plates of the dinoflagellate amphiesma cop, pop, cap, 4`, 4a, 7``, 7c, 6```, 2````, as, FM subdivided into several periplagellar areae, ls, rs, ps; pentagonal 1```` and hexagonal 2```` partiform; omegaform ps very large; adelopore on suture 1`/4`; growth of plates only on the overlapping margin, in the gonyaulacoidal fashion.
Cyst habit proximate, proximochorate, acavate to cavate, spheroidal, ovoidal, ovaloidal, polyhedral, size usually small; wall composed of thin pedium and luxuria, surface glabrous or ornamented, nonareate or areate, areation marked by finate ornament, limbi, and intraareate ornament, areation formula NR PR/cop, pop, cap, NR"/4`, NRa/4a, NR``/7``, NRc/7c, NR```/5```, NR````/2````, NRs/as, FM subdivided into several very small areas, ls, rs, ps; 2 antapicals partiform, large omegaform ps; porichnion on finis 1`/4`; finis 3``/4`` usually in characteristic dorsal location; archaeopyle apical/anterior intercalary, PR+1`+2`+3`+4`+1a+2a+3a+4a, operculum foederate, adnate to as, general opercular formula (PR+1`+2`+3`+4`+1a+2a+3a+4a)(a).
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Slimani, 1994:
Diagnosis:
Cyst small, proximate to proximochorate, acavate, spheroidal, ovoidal or polyhedrical, the epicyst much smaller than the hypocyst. Only the dorsal surface has parasutural crests which are low or relatively high, smooth, perforate or denticulate to crenulate and potentially with gonal processes at their junctions.
Paratabulation: ?`, 3-?6``, 2-?6c, 3-?6```, 0-1p, 1````. Often there are 3 precingular paraplates, 2-3 paracingulars, 3-4 postcingulars.
The paracingulum, segmented or not, is indicated by parallel parasutural crests.
The archaeopyle is precingular type P (1 single paraplate ?3``) with a free operculum, corresponding to the median precingular paraplate which is often situated to the right of a longitudinal median line.
[Phanerodinium, Deflandre, 1937a, p. 110; Emendations: Below, 1987b, p. 36–38; Slimani, 1994, p. 43.
Tax. jr. syn.: Fibradinium, Microdinium, Rhiptocorys and Subtilidinium, all according to Below (1987b, p.36) — however, Lentin and Williams (1989, p.135,243,316,354) retained all four genera. Stover and Evitt (1978, p.236) noted that the type of Phanerodinium, Phanerodinium cayeuxii, is embedded in flint so the nature of the archeopyle is uncertain. Accordingly, Lentin and Williams (1989, p.289) recommended that only Phanerodinium cayeuxii and Phanerodinium setiferum be included in Phanerodinium.
Type species: Palaeoperidinium cayeuxii (name not validly published), Deflandre, 1935 (pl. 6, fig.3)]
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Original description: [Deflandre, 1937]: (Translation: Stover and Evitt, 1978, p. 236):
Diagnosis:
The theca is divided into two very unequal parts by a generally deep, circular transverse furrow. In the orientation arbitrarily adopted, the epitheca is about three times higher than the hypotheca. The transverse furrow is somewhat less high than the hypotheca. It has not yet been possible to recognize a longitudinal furrow. The epitheca is appreciably pyramidal in form, with truncated apex; however, the faces can sometimes be a little swelled, which gives the whole of the organism a somewhat less prismatic appearance. The hypotheca is pyramidal or rounded. The plates that make up the theca are well visible and clearly delineated, the hypotheca being usually less easy to examine. None of the approximately 30 specimens of P.cayeuxi encountered so far has been enabled me to count the ant-equatorial plates. These plates are connected by an apical system which compromises a large, in all probability pentagonal, plate and a small rectangular, or rather elongated trapezoidal, plate. The latter could also be considered as an intercalary plate if judged from its lateral position.
The tabulation of the hypotheca is unknown. The transverse furrow, traversed by several sutures, is composed of several plates.
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Modified description:
Stover and Evitt 1978, p. 236:
Synopsis:
Cysts proximate, compressed ellipsoidal with an obtusely angular apex; epicyst much shorter than hypocyst; paratabulation indicated by parasutural ridges; ridges with or without gonal spines; archeopyle type uncertain.
Description:
Shape: Basically compressed ellipsoidal with an obtusely angular apex; antapex rounded or truncated. Epicyst much shorter than hypocyst.
Wall relationships: Autophragm only.
Wall features: Parasutural ridges usually clearly discernible on hypocyst, and generally less well expressed to indistinct on epicyst; ridges low, smooth or denticulate, and may be surmounted with slender acuminate gonal spines.
Paratabulation: Indicated mainly on the hypocyst by parasutural features; probably gonyaulacacean, formula: ?`, ?``, x-5c(6c), 4-6```, 1p, 1````. Usually only four postcingular paraplates are delimited completely, and these are interpreted as representing plates 2``` to 5```.
Archeopyle: Type uncertain; may be a triangular opening on the dorsal surface of the epicyst immediately above the paracingulum and to the right of the midline.
Paracingulum: Indicated by parallel, transverse, parasutural ridges, with or without connecting longitudinal ridges.
Parasulcus: Generally not indicated; the antapical position of the parasulcus may be inferred by a medial declivity in the parasutural ridge above paraplate 1````.
Size: Small.
Affinities:
Phanerodinium differs from Glyphanodinium in that some forms have serrate crests and gonal spines. Lack of precise information about the paratabulation on the epicyst and the archeopyle type in Phanerodinium precludes a more detailed comparison.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended descriptions:
Below, 1987: (Translation: after Translation Bureau of the Secretary of State, Canada. p. 98-99)
Diagnosis:
Arrangement of vesicles/plates of the dinoflagellate amphiesma cop, pop, cap, 4`, 4a, 7``, 7c, 6```, 2````, as, FM subdivided into several periplagellar areae, ls, rs, ps; pentagonal 1```` and hexagonal 2```` partiform; omegaform ps very large; adelopore on suture 1`/4`; growth of plates only on the overlapping margin, in the gonyaulacoidal fashion.
Cyst habit proximate, proximochorate, acavate to cavate, spheroidal, ovoidal, ovaloidal, polyhedral, size usually small; wall composed of thin pedium and luxuria, surface glabrous or ornamented, nonareate or areate, areation marked by finate ornament, limbi, and intraareate ornament, areation formula NR PR/cop, pop, cap, NR"/4`, NRa/4a, NR``/7``, NRc/7c, NR```/5```, NR````/2````, NRs/as, FM subdivided into several very small areas, ls, rs, ps; 2 antapicals partiform, large omegaform ps; porichnion on finis 1`/4`; finis 3``/4`` usually in characteristic dorsal location; archaeopyle apical/anterior intercalary, PR+1`+2`+3`+4`+1a+2a+3a+4a, operculum foederate, adnate to as, general opercular formula (PR+1`+2`+3`+4`+1a+2a+3a+4a)(a).
-------------------------------------
Slimani, 1994:
Diagnosis:
Cyst small, proximate to proximochorate, acavate, spheroidal, ovoidal or polyhedrical, the epicyst much smaller than the hypocyst. Only the dorsal surface has parasutural crests which are low or relatively high, smooth, perforate or denticulate to crenulate and potentially with gonal processes at their junctions.
Paratabulation: ?`, 3-?6``, 2-?6c, 3-?6```, 0-1p, 1````. Often there are 3 precingular paraplates, 2-3 paracingulars, 3-4 postcingulars.
The paracingulum, segmented or not, is indicated by parallel parasutural crests.
The archaeopyle is precingular type P (1 single paraplate ?3``) with a free operculum, corresponding to the median precingular paraplate which is often situated to the right of a longitudinal median line.