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Palaeoperidinium pyrophorum
Palaeoperidinium *pyrophorum (Ehrenberg, 1837b, pl.1, figs.1,4 ex Wetzel, 1933a, p.164–165) Sarjeant, 1967b, p.246. Emendations: Sarjeant, 1967b, p.246–247; Gocht and Netzel, 1976, p.403–405; Evitt et al., 1998, p.48–49; all as Palaeoperidinium pyrophorum.
Holotype: Ehrenberg, 1837b, pl.1, fig.4; Lejeune-Carpentier, 1938b, figs.1–4.
Originally Peridinium (Appendix B), subsequently (and now) Palaeoperidinium.
Taxonomic junior synonyms:
Peridinium (as Palaeoperidinium) basilium and Palaeoperidinium deflandrei, both according to Stover and Evitt (1978, p.218);
Pentagonum marginatum, Pentagonum sibiricum, and (at specific rank) Peridinium conicum subsp. larjakiense (subsequently Palaeoperidinium larjakiensis), all according to Lentin and Vozzhennikova (1990, p.61).
This combination was not validly published in Deflandre (1934, caption to text-fig.1) and Deflandre (1935, p.224) since the generic name was not validly published until 1967. The name Peridinium pyrophorum was not validly published in Ehrenberg (1837b) and Ehrenberg (1854, caption to pl.37) since no description was provided. Of Ehrenberg's (1837b) illustrations, only pl.1, fig.4 is of a single specimen, which thus has subsequently been accepted as the holotype. The specimen illustrated by Sarjeant (1967b, fig.3) as the holotype appears to be a different specimen.
Age: Late Cretaceous.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Palaeoperidinium pyrophorum (Ehrenberg, 1838) Sarjeant, 1967b, emend. Sarjeant, 1967b, emend. Gocht and Netzel, 1976, emend. Evitt et al., 1998. According to Evitt et al. (1998)
Shape: Ambitus pentagonal (peridinioid), with one apical horn and two antapical horns. Primary dorso-ventral compression strong. Episome and hyposome about equally long, their sides nearly straight to slightly concave; posterior margins concave between antapical horns; horns short, the left one more prominent than the right.
Phragma: Exophragm may occur alone or may enclose a thin-walled cornucavate to circumcavate intrathecal cyst, also with peridinioid ambitus; periphragm and exophragm not connected by pore fillings. Exophragm relatively thick (ca. 0.6 µm), its exterior surface nearly smooth or revealing only much subdued expression of the interior relief.
Tabulation: Completely delineated.
Archeopyle: Known only for exophragm.
Reticulum: Grooves/muri with rounded crests and smooth surface; lumina smooth to granulate, apiculate or corrugate. Trichocyst pores; Restricted to grooves/muri of reticulum, not isolated in lumina. Lists or septa; only sulcal lists present. Right list prominent; long, nearly straight, slightly inclined to anterior-posterior axis, with hook-like posterior terminus. Left list arcuate, about two-thirds as long as right.
Cingulum and reticulate areas of plates bounded by low ridges with simple crests.
Size: holotype length 92 µm, width 74 µm. Variability, length 88-136 µm, width 62-100 µm.
Affinities: This species differs from Deflandrea webbii which has a type I/3I archeopyle, and an overall shape that is typically deflandreoid. P.pyrophorum differs from P.cretaceum in general outline, the latter being subpentagonal with the sides of the episome tending to be convex and the horn bases tending to expand abruptly. Also useful is the width of the reticulate area in 3" and the denticulate outline at the base of the antapical horns.
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Original description: Ehrenberg, 1838, p. 110: Peridinium? (Glenodiniuim?) pyrophorum
New diagnosis: Lejeune-Carpentier, 1938, p.3: Peridinium pyrophorum
Theca, in ventral view, presenting a quite rounded outline, the hypotheca and even more the epitheca appearing clearly domed. A marked dorsoventral flattening.
A rather pronounced apical horn, broad at the base and blunt at the tip. Antapical horns, both swollen at the bases, the extremity of the left one elongate, the right one appearing so much the shorter, because it is slightly recurved ventrally.
Girdle: equatorial, hardly spiral, laevorotatoy, with marked borders especially at the hypotheca.
Anterior plate of ventral area ("sulcus") reaching well into the epitheca, the posterior plate hollowed into a straight groove, recurved at its extremity, curved to the right and fading into a beak. This depression halts at some distance from the antapical pole.
Tabulation: 4', 3a, 7'', 5''', 2''''. 1' diamond shaped, at the apex of which an apical pore opens, in contact with with two apicals: 2' and 4' and with two preequatorials: 1'' and 7''. Intercalaries 1a and 3a extending to the tip of the apical horn. 2a hexagonal. The sutures between plates 1' and 2' on one side, and 1'' and 2'' on the other side (just like the similar ones on the other side) forming a jagged line.
Preequatorial 1'' somewhat longer than 7''. Asymmetry of the hypotheca much more pronounced. Postequatorial 1''' descending only onto the middle of the distance between the girdle and the left antapical horn, while 5''' reaches the point where the right antapical horn thickens. Posterior 1'''' longer but less wide than 2''''.
Theca, appearing very thin, presents a marked sculpture over the entire surface, polygonal areolae succeeding each other, in certain places, in such a way, that, at low magnification, they give the impression of irregular lines.
Dimensions: Holotype: Length (including horns) 92 µm; width (at the level of the furrow of the girdle) 68 µm; idem (including the edges of the girdle) 74 µm.
Emended diagnosis: Sarjeant, 1967, p. 247
Shell ovoidal to subpolygonal, dorsoventrally somewhat flattened, with a short, rounded apical horn and two pointed antapical horns. The right-hand antapical horn is typically (or constantly) longer than the left-hand one. Tabulation 4', 3a, 7'', ?5c, 5''', 2'''': sutures and borders of cingulum marked by high, striate crests. Cingulum narrow, only slightly laevorotatory (its two ends scarcely differing in antero-posterioir position). Sulcus broadening from epitract to antapex, subdivided by poorly marked sutures. Shell surface markedly areolate. Archaeopyle formed by schism anterior to the cingulum, the sulcus typically (or constantly) remaining attached to the hypotract.
Dimensions (microns): Holotype: length 92, width 74, width of shell alone 67. Range: Length 88-136, width 62-100.
Supplemental description: Hultberg, 1985, p. 138
Proximate cyst, composed of endophragm and periphragm, closely appressed. The surface of the cyst is slightly reticulate. The shape of the cyst is typically peridinioid, with one apical and two antapical horns. Paratabulation is incompletely expressed by striate pandasutural bands. The striation is perpendicular to the parasutures. The paratabulation is typically peridiniacean, paratabulation formula:
4', 3a, 7'', xc, 5''', 2''''. The archeopyle is formed by the detachment of apical, intercalary, and precingular paraplates. The exact type of archeopyle can not be determined. Paracingulum is clearly indicated by folds in the cyst wall. It is slightly laevorotatory.
Holotype: Ehrenberg, 1837b, pl.1, fig.4; Lejeune-Carpentier, 1938b, figs.1–4.
Originally Peridinium (Appendix B), subsequently (and now) Palaeoperidinium.
Taxonomic junior synonyms:
Peridinium (as Palaeoperidinium) basilium and Palaeoperidinium deflandrei, both according to Stover and Evitt (1978, p.218);
Pentagonum marginatum, Pentagonum sibiricum, and (at specific rank) Peridinium conicum subsp. larjakiense (subsequently Palaeoperidinium larjakiensis), all according to Lentin and Vozzhennikova (1990, p.61).
This combination was not validly published in Deflandre (1934, caption to text-fig.1) and Deflandre (1935, p.224) since the generic name was not validly published until 1967. The name Peridinium pyrophorum was not validly published in Ehrenberg (1837b) and Ehrenberg (1854, caption to pl.37) since no description was provided. Of Ehrenberg's (1837b) illustrations, only pl.1, fig.4 is of a single specimen, which thus has subsequently been accepted as the holotype. The specimen illustrated by Sarjeant (1967b, fig.3) as the holotype appears to be a different specimen.
Age: Late Cretaceous.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Palaeoperidinium pyrophorum (Ehrenberg, 1838) Sarjeant, 1967b, emend. Sarjeant, 1967b, emend. Gocht and Netzel, 1976, emend. Evitt et al., 1998. According to Evitt et al. (1998)
Shape: Ambitus pentagonal (peridinioid), with one apical horn and two antapical horns. Primary dorso-ventral compression strong. Episome and hyposome about equally long, their sides nearly straight to slightly concave; posterior margins concave between antapical horns; horns short, the left one more prominent than the right.
Phragma: Exophragm may occur alone or may enclose a thin-walled cornucavate to circumcavate intrathecal cyst, also with peridinioid ambitus; periphragm and exophragm not connected by pore fillings. Exophragm relatively thick (ca. 0.6 µm), its exterior surface nearly smooth or revealing only much subdued expression of the interior relief.
Tabulation: Completely delineated.
Archeopyle: Known only for exophragm.
Reticulum: Grooves/muri with rounded crests and smooth surface; lumina smooth to granulate, apiculate or corrugate. Trichocyst pores; Restricted to grooves/muri of reticulum, not isolated in lumina. Lists or septa; only sulcal lists present. Right list prominent; long, nearly straight, slightly inclined to anterior-posterior axis, with hook-like posterior terminus. Left list arcuate, about two-thirds as long as right.
Cingulum and reticulate areas of plates bounded by low ridges with simple crests.
Size: holotype length 92 µm, width 74 µm. Variability, length 88-136 µm, width 62-100 µm.
Affinities: This species differs from Deflandrea webbii which has a type I/3I archeopyle, and an overall shape that is typically deflandreoid. P.pyrophorum differs from P.cretaceum in general outline, the latter being subpentagonal with the sides of the episome tending to be convex and the horn bases tending to expand abruptly. Also useful is the width of the reticulate area in 3" and the denticulate outline at the base of the antapical horns.
--------------------------------------------------
Original description: Ehrenberg, 1838, p. 110: Peridinium? (Glenodiniuim?) pyrophorum
New diagnosis: Lejeune-Carpentier, 1938, p.3: Peridinium pyrophorum
Theca, in ventral view, presenting a quite rounded outline, the hypotheca and even more the epitheca appearing clearly domed. A marked dorsoventral flattening.
A rather pronounced apical horn, broad at the base and blunt at the tip. Antapical horns, both swollen at the bases, the extremity of the left one elongate, the right one appearing so much the shorter, because it is slightly recurved ventrally.
Girdle: equatorial, hardly spiral, laevorotatoy, with marked borders especially at the hypotheca.
Anterior plate of ventral area ("sulcus") reaching well into the epitheca, the posterior plate hollowed into a straight groove, recurved at its extremity, curved to the right and fading into a beak. This depression halts at some distance from the antapical pole.
Tabulation: 4', 3a, 7'', 5''', 2''''. 1' diamond shaped, at the apex of which an apical pore opens, in contact with with two apicals: 2' and 4' and with two preequatorials: 1'' and 7''. Intercalaries 1a and 3a extending to the tip of the apical horn. 2a hexagonal. The sutures between plates 1' and 2' on one side, and 1'' and 2'' on the other side (just like the similar ones on the other side) forming a jagged line.
Preequatorial 1'' somewhat longer than 7''. Asymmetry of the hypotheca much more pronounced. Postequatorial 1''' descending only onto the middle of the distance between the girdle and the left antapical horn, while 5''' reaches the point where the right antapical horn thickens. Posterior 1'''' longer but less wide than 2''''.
Theca, appearing very thin, presents a marked sculpture over the entire surface, polygonal areolae succeeding each other, in certain places, in such a way, that, at low magnification, they give the impression of irregular lines.
Dimensions: Holotype: Length (including horns) 92 µm; width (at the level of the furrow of the girdle) 68 µm; idem (including the edges of the girdle) 74 µm.
Emended diagnosis: Sarjeant, 1967, p. 247
Shell ovoidal to subpolygonal, dorsoventrally somewhat flattened, with a short, rounded apical horn and two pointed antapical horns. The right-hand antapical horn is typically (or constantly) longer than the left-hand one. Tabulation 4', 3a, 7'', ?5c, 5''', 2'''': sutures and borders of cingulum marked by high, striate crests. Cingulum narrow, only slightly laevorotatory (its two ends scarcely differing in antero-posterioir position). Sulcus broadening from epitract to antapex, subdivided by poorly marked sutures. Shell surface markedly areolate. Archaeopyle formed by schism anterior to the cingulum, the sulcus typically (or constantly) remaining attached to the hypotract.
Dimensions (microns): Holotype: length 92, width 74, width of shell alone 67. Range: Length 88-136, width 62-100.
Supplemental description: Hultberg, 1985, p. 138
Proximate cyst, composed of endophragm and periphragm, closely appressed. The surface of the cyst is slightly reticulate. The shape of the cyst is typically peridinioid, with one apical and two antapical horns. Paratabulation is incompletely expressed by striate pandasutural bands. The striation is perpendicular to the parasutures. The paratabulation is typically peridiniacean, paratabulation formula:
4', 3a, 7'', xc, 5''', 2''''. The archeopyle is formed by the detachment of apical, intercalary, and precingular paraplates. The exact type of archeopyle can not be determined. Paracingulum is clearly indicated by folds in the cyst wall. It is slightly laevorotatory.