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Palaeoperidinium
From Williams et al., 2017:
[Palaeoperidinium, Deflandre, 1934, p. 968 ex Sarjeant, 1967b, p. 246-247; Emendation: Evitt et al., 1998, p. 46, 48.
Tax. jr. syn.: Morkallacysta according to Lentin and Williams (1976, p.150,160,161) - however, Stover and Evitt (1978, p.113-114) retained Morkallacysta.
The name Palaeoperidinium was not validly published in Deflandre (1934) since that author did not designate a type, which he was obliged to do as he was using zoological nomenclature (I.C.Z.N. Article 13b). No type was designated until Sarjeant (1967b) did so; he also brought the generic name under the auspices of the I.C.B.N. (now the I.C.N.). This interpretation differs from that in Lentin and Williams (1993) and accords with that of Loeblich Jr. and Loeblich III (1966) and, in essence, also that of Sarjeant (1967b). In contrast to the contention of Tappan and Loeblich Jr. (1967, p.526), Deflandre (1934, p.968) did publish a description of Palaeoperidinium as a footnote. In validating the generic name, Sarjeant (1967b, p.246) provided an emended diagnosis.
Type species: Peridinium pyrophorum, Ehrenberg, 1837b (pl.1, fig.4)]
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Original description: [Deflandre, 1935]: (Translation: Stover and Evitt, 1978, p. 217):
Diagnosis:
Under the name of Palaeoperidinium I group all the dinoflagellates of flint with the physiognomy of Peridinium, whose tabulation, although present, cannot be studied in detail. This fact, consequently, does not allow them to classified with certainty in one of the extant genera, which differ among themselves only in tabulation.
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Sarjeant, 1967:
Description:
Proximate cysts, ovoidal or polygonal to subpolygonal in outline, with apical horn and two antapical horns.
Reflected tabulation 4`, 3a, 7``, 5-?7c, 5```, 2````; sutures with or without raised crests.
Archaeopyle epitractal.
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Modified description:
Stover and Evitt 1978, p. 217-218:
Synopsis:
Cysts proximate, compressed peridinoid; an apical and two antapical horns typically well developed; paratabulation, when discernible peridiniacean; combination archeopyle, Type AtI3P, operculum free or adherent, separated from epicyst by transapical suture, and may have a suture along the dorsal apical margin of paracingulum.
Description:
Shape: Compressed Peridinoid, typically with well-developed apical and antapical horns; outline may be modified by folding.
Wall relationships: Endophragm conspicuous to obscure, and may be undetectable or absent; when visible, cysts are generally circumcavate.
Wall features: No parasutural features. Periphragm smooth to finely ornamented or with reticulate or granulate intratabulare areas; later separated by striated pandasuturate bands, with most striations perpendicular to margins of intratabular areas.
Paratabulation: Indicated by archeopyle only, or by intratabular features in conjunction with pandasuturate areas; peridiniacaen, formula: 4`, 3a, 7``, 0-6c, 5```, 2````, 0-5s.
Archeopyle: Combination, Type AtI3P, large, occupies most of the dorsal surface of the epicyst; operculum free or adherent, comprises paraplates 3`, 1a-3a and 3``-5``, separates from the cyst along a transapical suture located at the dorsal apical margin of the paracingulum.
Paracingulum: Faintly to clearly indicated by low, transverse, parallel parasutural ridges.
Parasulcus: Poorly to clearly indicated on the midventral part of the hypocyst by the presence of paraplates or by the lack of ornamentation.
Size: Intermediate to large.
Afinities:
Palaeoperidinium differs from Saeptodinium, which has the same type archeopyle, in having prominent apical and antapical horns and less rounded outline. Laciniadinium and Luxadinium differ from Palaeoperidinium in not having a third apical paraplate involved in the formation of the archeopyle.
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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.
Palaeoperidinium Deflandre, 1934 ex Sarjeant, 1967b, emend. Evitt et al., 1998. According to Evitt et al. (1998), Palaeoperidinium has a typically pentagonal (peridinioid) ambitus with one apical and two antapical horns. There may be three walls. The outermost, principal wall is an exophragm whose interior surface preserves details of the exterior surface of the theca in negative relief (as a cast). In addition, thin and delicate periphragm and endophragm may constitute a structure that resembles a conventional cornucavate to circumcavate cyst and lies close to or remote from the exophragm, but this structure may be absent or difficult to demonstrate. Relief on exterior exophragm surface (corresponding to relief on exterior of theca) depends on relative exophragm thickness and ranges from theca-like with distinctly reticulate and spinose plates and corrugate growth bands (thinnest exophragm) to subdued but with major features distinguishable (moderately thick), to virtually smooth. Tabulation: Developed on exophragm only, ortho-hexa peridinioid (4`, 3a, 7", 5c, t, 5``` , 2```` , 4s). Principal plates polygonal typically with reticulate pattern; plates separated by transversely corrugate growth bands. Cingulum with five plates; small transitional plate in addition. Anterior sulcal extends notably onto epicyst, posterior sulcal large and subtriangular, other small sulcals may be visible. Apical pore plate and small ventral canal plate present at apex. Archeopyle known only in exophragm, hemiepicystal and operculate (Type A3I3P). Reticulum. Network of grooves representing ridges on theca. Trichocyst pores. Pore fillings form papillae on interior exophragm surface. Lists or septa. A list along each edge of the cingulum, a pair of parallel lists along the sulcus, and lists extending from apex along sides of first apical plate may be present. Right sulcal list rises from sulcal plates.
[Palaeoperidinium, Deflandre, 1934, p. 968 ex Sarjeant, 1967b, p. 246-247; Emendation: Evitt et al., 1998, p. 46, 48.
Tax. jr. syn.: Morkallacysta according to Lentin and Williams (1976, p.150,160,161) - however, Stover and Evitt (1978, p.113-114) retained Morkallacysta.
The name Palaeoperidinium was not validly published in Deflandre (1934) since that author did not designate a type, which he was obliged to do as he was using zoological nomenclature (I.C.Z.N. Article 13b). No type was designated until Sarjeant (1967b) did so; he also brought the generic name under the auspices of the I.C.B.N. (now the I.C.N.). This interpretation differs from that in Lentin and Williams (1993) and accords with that of Loeblich Jr. and Loeblich III (1966) and, in essence, also that of Sarjeant (1967b). In contrast to the contention of Tappan and Loeblich Jr. (1967, p.526), Deflandre (1934, p.968) did publish a description of Palaeoperidinium as a footnote. In validating the generic name, Sarjeant (1967b, p.246) provided an emended diagnosis.
Type species: Peridinium pyrophorum, Ehrenberg, 1837b (pl.1, fig.4)]
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Original description: [Deflandre, 1935]: (Translation: Stover and Evitt, 1978, p. 217):
Diagnosis:
Under the name of Palaeoperidinium I group all the dinoflagellates of flint with the physiognomy of Peridinium, whose tabulation, although present, cannot be studied in detail. This fact, consequently, does not allow them to classified with certainty in one of the extant genera, which differ among themselves only in tabulation.
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Sarjeant, 1967:
Description:
Proximate cysts, ovoidal or polygonal to subpolygonal in outline, with apical horn and two antapical horns.
Reflected tabulation 4`, 3a, 7``, 5-?7c, 5```, 2````; sutures with or without raised crests.
Archaeopyle epitractal.
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Modified description:
Stover and Evitt 1978, p. 217-218:
Synopsis:
Cysts proximate, compressed peridinoid; an apical and two antapical horns typically well developed; paratabulation, when discernible peridiniacean; combination archeopyle, Type AtI3P, operculum free or adherent, separated from epicyst by transapical suture, and may have a suture along the dorsal apical margin of paracingulum.
Description:
Shape: Compressed Peridinoid, typically with well-developed apical and antapical horns; outline may be modified by folding.
Wall relationships: Endophragm conspicuous to obscure, and may be undetectable or absent; when visible, cysts are generally circumcavate.
Wall features: No parasutural features. Periphragm smooth to finely ornamented or with reticulate or granulate intratabulare areas; later separated by striated pandasuturate bands, with most striations perpendicular to margins of intratabular areas.
Paratabulation: Indicated by archeopyle only, or by intratabular features in conjunction with pandasuturate areas; peridiniacaen, formula: 4`, 3a, 7``, 0-6c, 5```, 2````, 0-5s.
Archeopyle: Combination, Type AtI3P, large, occupies most of the dorsal surface of the epicyst; operculum free or adherent, comprises paraplates 3`, 1a-3a and 3``-5``, separates from the cyst along a transapical suture located at the dorsal apical margin of the paracingulum.
Paracingulum: Faintly to clearly indicated by low, transverse, parallel parasutural ridges.
Parasulcus: Poorly to clearly indicated on the midventral part of the hypocyst by the presence of paraplates or by the lack of ornamentation.
Size: Intermediate to large.
Afinities:
Palaeoperidinium differs from Saeptodinium, which has the same type archeopyle, in having prominent apical and antapical horns and less rounded outline. Laciniadinium and Luxadinium differ from Palaeoperidinium in not having a third apical paraplate involved in the formation of the 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.
Palaeoperidinium Deflandre, 1934 ex Sarjeant, 1967b, emend. Evitt et al., 1998. According to Evitt et al. (1998), Palaeoperidinium has a typically pentagonal (peridinioid) ambitus with one apical and two antapical horns. There may be three walls. The outermost, principal wall is an exophragm whose interior surface preserves details of the exterior surface of the theca in negative relief (as a cast). In addition, thin and delicate periphragm and endophragm may constitute a structure that resembles a conventional cornucavate to circumcavate cyst and lies close to or remote from the exophragm, but this structure may be absent or difficult to demonstrate. Relief on exterior exophragm surface (corresponding to relief on exterior of theca) depends on relative exophragm thickness and ranges from theca-like with distinctly reticulate and spinose plates and corrugate growth bands (thinnest exophragm) to subdued but with major features distinguishable (moderately thick), to virtually smooth. Tabulation: Developed on exophragm only, ortho-hexa peridinioid (4`, 3a, 7", 5c, t, 5``` , 2```` , 4s). Principal plates polygonal typically with reticulate pattern; plates separated by transversely corrugate growth bands. Cingulum with five plates; small transitional plate in addition. Anterior sulcal extends notably onto epicyst, posterior sulcal large and subtriangular, other small sulcals may be visible. Apical pore plate and small ventral canal plate present at apex. Archeopyle known only in exophragm, hemiepicystal and operculate (Type A3I3P). Reticulum. Network of grooves representing ridges on theca. Trichocyst pores. Pore fillings form papillae on interior exophragm surface. Lists or septa. A list along each edge of the cingulum, a pair of parallel lists along the sulcus, and lists extending from apex along sides of first apical plate may be present. Right sulcal list rises from sulcal plates.