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Cribroperidinium
From Williams et al., 2017:
[Cribroperidinium, Neale and Sarjeant, 1962, p. 443; Emendations: Davey, 1969a, p. 125; Sarjeant, 1982b, p. 40-41; Helenes, 1984, p. 112-113.
Type species: Cribroperidinium sepimentum, Neale and Sarjeant, 1962 (pl.19, fig.4; text-fig.3a–b)]
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Original description: [Neale and Sarejeant, 1962]:
Diagnosis: Theca of varied shape and ornament, with longitudinal and transversal furrows and with the following tabulation: 6`, 1-5a, 8``, 9```, 1p, 2pv, 6-?7 pc, 0````.
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Emended description:
Davey, 1969:
Diagnosis:
Proximate cysts, subspherical to ovoidal, thick-walled. Crests numerous and well developed. Tabulation ?6`, (1-5a), 8-9``, 0c, 9```, 1p, 1-3 p.v. (5-7 p.c.), 0```` (--?2````). Cingulum laevo-rotatory.
Archaeopyle precingular.
---------------------------------
Sarjeant, 1982:
Diagnosis:
Proximate to proximochorate dinoflagellates, typically of intermediate to large, rarely (or never) of small, size. Ambitus spheroidal to broadly ellipsoidal or subpolygonal, typically with an apical prominence or horn; acavate to acrocavate or cornucavate. Parasutures marked by lines, ridges or crests of varied height and form; accessory crests partially or completely subdivide the larger paraplates and mask the paratabulation. The latter, when determinable, accords with the pattern 0-2pa, 3-4`, 0-?2a, 6``, X or 6-7c, 5-6```,; 1p, 1-?````; the sulcus is usually undivided. Paraplate 4` is elongate, almost as long as 1` and having only a short boundary with 6``; the latter paraplate is typically roughly triangular, with concave to markedly convex lateral flanks. The boundary between paraplates 4` and 6" intersects the right lateral boundary of 1` in a position anterior to the junction of the latter paraplate with the sulcus. Gonal spines are lacking. Surface of phragma smooth, granular, nodose, punctate or reticulate. Archaeopyle single-plate precingular, formed by loss of paraplate 3``; operculum reduced.
Affinities:
Cribroperidinium differs from Millioudodinium, and resembles Corrudinium, in its intensive development of secondary crests; it differs from the latter genus in size and the development of an apical horn.
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Helenes, 1984:
Description:
Shape: Body subspherical to ovoidal. Equatorial section is circular with a slight indentation in the sulcal area. Outline in ventral view ranges from
circular to elliptical, to almost rhomboidal. An apical horn of variable size and shape is usually present.
Size: Small to large. Total length ranges from c. 30 µm to c. 150 µm.
Wall structure: Acavate. Autophragm only, it may be differentiated into a homogeneous and structureless inner part and a vesicular to "spongy looking" outer part, but without separation between layers.
Archeopyle: Precingular archeopyle, Type P4 (mid-dorsal paraplate 4). Operculum is usually enlarged especially along the cingular side. Archeopyle normally has a rounded appearance. Operculum free, although it may be adherent.
External features: Low parasutural ridges that may be continuous or discontinuous, simple or complicated, or may be represented by rows of
granules or spines. Low intratabular ridges and/or granules or low spines are usually present. The intratabular ridges commonly seem to delineate growth bands.
Paratabulation: Parasutural features define the following paraplates (Text-Figure 2): 1 preapical (P), 4 apicals (A, B, C, and 1u), 6 precingulars (2, 3, 4, 5, 6, and 1i), 6 cingulars (au, b, c, d, e, and fi), 5 sulcals (fu, ai, li, Im and Z), 6 postcingulars (lu, II, III, IV, V, and Vl), 1 posterior intercalary (X), and 1 antapi- cal (Y). The paratabulation pattern is characterized by an L-type ventral organization, with a roughly pentagonal 1i contacting both apicals A and 1u; elongated A and 1u, small lu, and crescent-shaped X and Z. The apical area includes relatively small and quadrate B and C, and dorsal contact of A and B; a constriction at the tip of the apical horn reflects the presence of the preapical structure P; a porichnion has been observed in all the species studied in detail. Postcingular paraplate IV is located partially or totally on the left side of the hypocyst, so that the postcingular parasuture IV/V lies to the left of the precingular parasuture 4/5. Postcingular paraplate II is small, while V is very large, the contact V/Y ranges from rectilinear to gabled; antapical paraplate Y is sexiform (i.e., six-sided), oblong (i.e., longer than wide), asymmetrical (right side longer than left), and its longitudinal axis is inclined to the left relative to the dorso-ventral axis.
Affinities:
Species in this genus differ from one another chiefly by the height and shape of the parasutural and intratabular ridges; geometry, size and abundance of the intratabular elements of ornamentation (commonly short spines or granules, or ridges); size and shape of the body and apical horn; thickness of the wall, and relative sizes of the epicyst and hypocyst. Some characteristics useful in recognizing a Cribroperidinium - like paratabulation pattern are, in ventral view: arcuate- shaped Z and X together with an L-type ventral organization, and the relatively anterior position of the parasuture VI/Y relative to X/Y; in antapical view: the oblong, sexiform, asymmetric form of Y, the relatively large size of IV and especially V, and the almost mid-dorsal position of IV/V.
An extensive discussion on Cribroperidinium and related taxa within the "Cribroperidinium Complex" is given in Helenes, 1984.
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Modified description:
Stover and Evitt 1978, p. 149-150:
Synopsis:
Cysts proximate, autocyst subspherical to ellipsoidal, usually with a prominent apical horn; paratabulation gonyaulacacean, indicated by parasutural ridges septa, or rows of closely spaced projections; accessory ridges or septa present on most paraplates; archeopyle precingular, Type P.
Description:
Shape: Body subspherical to ellipsoidal, usually with a prominent apical horn.
Wall relationships: Generally autophragm only; individual wall layers may be discernible on some species.
Wall features: Parasutural ridges or septa, continuous or interrupted, smooth, perforate or striate; may have smooth, serrate, or spinulate crests. On some forms, parasutural features are rows of closely spaced spinules. On most paraplates, accessory ridges or septa, like those in parasutural positions, extend completely or partly across the paraplate and may be curved or straight. Additionally, features of low to moderate relief may occur on paraplates.
Paratabulation: Indicated by parasutural features, often masked or of intricate appearance because of accessory ridges or septa; gonyaulacacean, formula: 3-4`, 0-1a, 6``, Xc, 5-6```, 1p, 1````, 0-1s.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Normally indicated by parallel transverse ridges only; occasionally crossbars (number unknown) may be present.
Parasulcus: Margined by parasutural features and generally free of ornamentation; may be mainly on hypocyst.
Size: Intermediate to large, generally the latter.
Affinities:
Cribroperidinium differs from Millioudodinium in having accessory ridges in the areas between parasutural ridges; in Millioudodinium, these areas lack accessory ridges. Cribroperidinium differs from Corrudinium in being considerably larger and in usually having an apical horn, which Corrudinium lacks.
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Poulsen, 1996, p.71:
Remarks:
Fensome et al. (1993, p. 84) and Williams et al. (1993) discussed dinoflagellate cysts in which the boundary between the postcingular paraplates 4"` and 5"` is significantly distal in location relative to the boundary between precingular paraplates 3" and 4", that is with a hypocyst which is twisted proximally relative to the epicyst. Fensome et al. (1993, p. 84) referred to such a configuration as dextrally contorted. This is found in, for example, Cribroperidinium.
The twisted hypocyst has a major impact on the tabulation of Cribroperidinium. The first two postcingular paraplates (1"` and 2"`) are reduced in size. The antapical paraplate 1"", tends to be strongly asymmetrical. Williams et al. (1993) terms this an inclined sexiform 1"" in which the right lateral side is longer than either the left lateral or dorsal side and the contact between 1"" and the postcingular paraplate 6"` is appreciably closer to the paracingulum than the 1""/1p contact.
Another effect of dextral contortion is that the posterior paraplates lp and ps tend to become narrow (Helenes, 1984) and together form a U-shape around the posterior end of the sulcus (Williams, written commun., 1991). These features are shown in the illustrations of Acanthaulax granulatum and Acanthaulax granuliferum in Brenner (1988, pl. 1, figs. 3a, 4a, 5, pl. 2, fig. 1a).
Brenner (1988, text-fig. 16) describes two preparaplates in Acanthaulax; however, in my opinion the figured specimen (Brenner, 1988, pl. 1, fig. 6) only shows one preapical paraplate. It appears to be similar to the preapical paraplate shown in Helenes (1984, pl. 4, figs. 1, 2, 13, 14, pl. 5, figs. 7, 10, 11).
Helenes (1984, p. 116) suggested that: `if the paratabulation pattern of Acanthaulax venusta proves to be compatible with that of Cribroperidinium as defined herein, then this species should be considered as a taxonomic junior synonym of Cribroperidinium granulatum, and consequently the genus Acanthaulax should be considered as a taxonomic junior synonym of Cribroperidinium`.
Acanthaulax venusta, which is the type species of Acanthaulax, is transferred to Cribroperidinium, making Acanthaulax a taxonomic junior synonym of Cribroperidinium.
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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.
Cribroperidinium Neale and Sarjeant, 1962, emend. Helenes, 1984. From the synopsis provided by Helenes (1984) who emended the diagnosis of the genus, Subspherical to ovoidal proximate cysts having a sexiform gonyaulacoid paratabulation pattern indicated by parasutural features in the intratabular areas of major paraplates. Ventral organization L-type; precingular 1i (6") contacts apicals A(4`) and 1u(1`); X(1p) and Z (ps) narrow, arcuate; Iu(1"') distinct, but small, II(2"') relatively small; Y(1"'') asymmetric, oblong in conjunction with nearly did-dorsal position of IV/V(4/5"') which lies to the left of 4/5(3/4"). Apical area includes P (but not Q) and B(2`) contacts A(4`) dorsal to P. Apical horn usually present: porichnion visible with suitable magnification.
[Cribroperidinium, Neale and Sarjeant, 1962, p. 443; Emendations: Davey, 1969a, p. 125; Sarjeant, 1982b, p. 40-41; Helenes, 1984, p. 112-113.
Type species: Cribroperidinium sepimentum, Neale and Sarjeant, 1962 (pl.19, fig.4; text-fig.3a–b)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Neale and Sarejeant, 1962]:
Diagnosis: Theca of varied shape and ornament, with longitudinal and transversal furrows and with the following tabulation: 6`, 1-5a, 8``, 9```, 1p, 2pv, 6-?7 pc, 0````.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Davey, 1969:
Diagnosis:
Proximate cysts, subspherical to ovoidal, thick-walled. Crests numerous and well developed. Tabulation ?6`, (1-5a), 8-9``, 0c, 9```, 1p, 1-3 p.v. (5-7 p.c.), 0```` (--?2````). Cingulum laevo-rotatory.
Archaeopyle precingular.
---------------------------------
Sarjeant, 1982:
Diagnosis:
Proximate to proximochorate dinoflagellates, typically of intermediate to large, rarely (or never) of small, size. Ambitus spheroidal to broadly ellipsoidal or subpolygonal, typically with an apical prominence or horn; acavate to acrocavate or cornucavate. Parasutures marked by lines, ridges or crests of varied height and form; accessory crests partially or completely subdivide the larger paraplates and mask the paratabulation. The latter, when determinable, accords with the pattern 0-2pa, 3-4`, 0-?2a, 6``, X or 6-7c, 5-6```,; 1p, 1-?````; the sulcus is usually undivided. Paraplate 4` is elongate, almost as long as 1` and having only a short boundary with 6``; the latter paraplate is typically roughly triangular, with concave to markedly convex lateral flanks. The boundary between paraplates 4` and 6" intersects the right lateral boundary of 1` in a position anterior to the junction of the latter paraplate with the sulcus. Gonal spines are lacking. Surface of phragma smooth, granular, nodose, punctate or reticulate. Archaeopyle single-plate precingular, formed by loss of paraplate 3``; operculum reduced.
Affinities:
Cribroperidinium differs from Millioudodinium, and resembles Corrudinium, in its intensive development of secondary crests; it differs from the latter genus in size and the development of an apical horn.
---------------------------------
Helenes, 1984:
Description:
Shape: Body subspherical to ovoidal. Equatorial section is circular with a slight indentation in the sulcal area. Outline in ventral view ranges from
circular to elliptical, to almost rhomboidal. An apical horn of variable size and shape is usually present.
Size: Small to large. Total length ranges from c. 30 µm to c. 150 µm.
Wall structure: Acavate. Autophragm only, it may be differentiated into a homogeneous and structureless inner part and a vesicular to "spongy looking" outer part, but without separation between layers.
Archeopyle: Precingular archeopyle, Type P4 (mid-dorsal paraplate 4). Operculum is usually enlarged especially along the cingular side. Archeopyle normally has a rounded appearance. Operculum free, although it may be adherent.
External features: Low parasutural ridges that may be continuous or discontinuous, simple or complicated, or may be represented by rows of
granules or spines. Low intratabular ridges and/or granules or low spines are usually present. The intratabular ridges commonly seem to delineate growth bands.
Paratabulation: Parasutural features define the following paraplates (Text-Figure 2): 1 preapical (P), 4 apicals (A, B, C, and 1u), 6 precingulars (2, 3, 4, 5, 6, and 1i), 6 cingulars (au, b, c, d, e, and fi), 5 sulcals (fu, ai, li, Im and Z), 6 postcingulars (lu, II, III, IV, V, and Vl), 1 posterior intercalary (X), and 1 antapi- cal (Y). The paratabulation pattern is characterized by an L-type ventral organization, with a roughly pentagonal 1i contacting both apicals A and 1u; elongated A and 1u, small lu, and crescent-shaped X and Z. The apical area includes relatively small and quadrate B and C, and dorsal contact of A and B; a constriction at the tip of the apical horn reflects the presence of the preapical structure P; a porichnion has been observed in all the species studied in detail. Postcingular paraplate IV is located partially or totally on the left side of the hypocyst, so that the postcingular parasuture IV/V lies to the left of the precingular parasuture 4/5. Postcingular paraplate II is small, while V is very large, the contact V/Y ranges from rectilinear to gabled; antapical paraplate Y is sexiform (i.e., six-sided), oblong (i.e., longer than wide), asymmetrical (right side longer than left), and its longitudinal axis is inclined to the left relative to the dorso-ventral axis.
Affinities:
Species in this genus differ from one another chiefly by the height and shape of the parasutural and intratabular ridges; geometry, size and abundance of the intratabular elements of ornamentation (commonly short spines or granules, or ridges); size and shape of the body and apical horn; thickness of the wall, and relative sizes of the epicyst and hypocyst. Some characteristics useful in recognizing a Cribroperidinium - like paratabulation pattern are, in ventral view: arcuate- shaped Z and X together with an L-type ventral organization, and the relatively anterior position of the parasuture VI/Y relative to X/Y; in antapical view: the oblong, sexiform, asymmetric form of Y, the relatively large size of IV and especially V, and the almost mid-dorsal position of IV/V.
An extensive discussion on Cribroperidinium and related taxa within the "Cribroperidinium Complex" is given in Helenes, 1984.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt 1978, p. 149-150:
Synopsis:
Cysts proximate, autocyst subspherical to ellipsoidal, usually with a prominent apical horn; paratabulation gonyaulacacean, indicated by parasutural ridges septa, or rows of closely spaced projections; accessory ridges or septa present on most paraplates; archeopyle precingular, Type P.
Description:
Shape: Body subspherical to ellipsoidal, usually with a prominent apical horn.
Wall relationships: Generally autophragm only; individual wall layers may be discernible on some species.
Wall features: Parasutural ridges or septa, continuous or interrupted, smooth, perforate or striate; may have smooth, serrate, or spinulate crests. On some forms, parasutural features are rows of closely spaced spinules. On most paraplates, accessory ridges or septa, like those in parasutural positions, extend completely or partly across the paraplate and may be curved or straight. Additionally, features of low to moderate relief may occur on paraplates.
Paratabulation: Indicated by parasutural features, often masked or of intricate appearance because of accessory ridges or septa; gonyaulacacean, formula: 3-4`, 0-1a, 6``, Xc, 5-6```, 1p, 1````, 0-1s.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Normally indicated by parallel transverse ridges only; occasionally crossbars (number unknown) may be present.
Parasulcus: Margined by parasutural features and generally free of ornamentation; may be mainly on hypocyst.
Size: Intermediate to large, generally the latter.
Affinities:
Cribroperidinium differs from Millioudodinium in having accessory ridges in the areas between parasutural ridges; in Millioudodinium, these areas lack accessory ridges. Cribroperidinium differs from Corrudinium in being considerably larger and in usually having an apical horn, which Corrudinium lacks.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Poulsen, 1996, p.71:
Remarks:
Fensome et al. (1993, p. 84) and Williams et al. (1993) discussed dinoflagellate cysts in which the boundary between the postcingular paraplates 4"` and 5"` is significantly distal in location relative to the boundary between precingular paraplates 3" and 4", that is with a hypocyst which is twisted proximally relative to the epicyst. Fensome et al. (1993, p. 84) referred to such a configuration as dextrally contorted. This is found in, for example, Cribroperidinium.
The twisted hypocyst has a major impact on the tabulation of Cribroperidinium. The first two postcingular paraplates (1"` and 2"`) are reduced in size. The antapical paraplate 1"", tends to be strongly asymmetrical. Williams et al. (1993) terms this an inclined sexiform 1"" in which the right lateral side is longer than either the left lateral or dorsal side and the contact between 1"" and the postcingular paraplate 6"` is appreciably closer to the paracingulum than the 1""/1p contact.
Another effect of dextral contortion is that the posterior paraplates lp and ps tend to become narrow (Helenes, 1984) and together form a U-shape around the posterior end of the sulcus (Williams, written commun., 1991). These features are shown in the illustrations of Acanthaulax granulatum and Acanthaulax granuliferum in Brenner (1988, pl. 1, figs. 3a, 4a, 5, pl. 2, fig. 1a).
Brenner (1988, text-fig. 16) describes two preparaplates in Acanthaulax; however, in my opinion the figured specimen (Brenner, 1988, pl. 1, fig. 6) only shows one preapical paraplate. It appears to be similar to the preapical paraplate shown in Helenes (1984, pl. 4, figs. 1, 2, 13, 14, pl. 5, figs. 7, 10, 11).
Helenes (1984, p. 116) suggested that: `if the paratabulation pattern of Acanthaulax venusta proves to be compatible with that of Cribroperidinium as defined herein, then this species should be considered as a taxonomic junior synonym of Cribroperidinium granulatum, and consequently the genus Acanthaulax should be considered as a taxonomic junior synonym of Cribroperidinium`.
Acanthaulax venusta, which is the type species of Acanthaulax, is transferred to Cribroperidinium, making Acanthaulax a taxonomic junior synonym of Cribroperidinium.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Cribroperidinium Neale and Sarjeant, 1962, emend. Helenes, 1984. From the synopsis provided by Helenes (1984) who emended the diagnosis of the genus, Subspherical to ovoidal proximate cysts having a sexiform gonyaulacoid paratabulation pattern indicated by parasutural features in the intratabular areas of major paraplates. Ventral organization L-type; precingular 1i (6") contacts apicals A(4`) and 1u(1`); X(1p) and Z (ps) narrow, arcuate; Iu(1"') distinct, but small, II(2"') relatively small; Y(1"'') asymmetric, oblong in conjunction with nearly did-dorsal position of IV/V(4/5"') which lies to the left of 4/5(3/4"). Apical area includes P (but not Q) and B(2`) contacts A(4`) dorsal to P. Apical horn usually present: porichnion visible with suitable magnification.