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Wilsonidium
From Williams et al., 2017:
[Wilsonidium, Lentin and Williams, 1976, p.138–139; Emendation: Williams et al., 2015, p. 318.
Type species: as Wetzeliella tabulata, Wilson, 1967c (figs.4–6)]
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Original description: [Lentin and Williams, 1976]:
Description:
Pericyst: Ambitus rhomboidal to pentagonal (peridinioid). Apex rounded or more commonly prolonged into an apical horn. Two equal precingular horns usually present, occasionally reduced or absent. Antapex prolonged into one eccentrically located antapical horn, the left, or two unequal symmetrically located antapical horns, the left always being the longer, the right being reduced or vestigial. From the position of the pericingular horns, the epipericyst and hypopericyst may be equal in size, or unequal, in which case the hypopericyst is always the larger. Compression dorso-ventral, usually extreme.
Endocyst: Ambitus circular to ovoidal to ellipsoidal. Rarely may be completely appressed to the pericyst when it has the same shape. Generally only partially in contact with the pericyst and then in the interhorn areas. Compression dorso-ventral.
Pericoels: When the endocyst and pericyst are in contact in the interhorn areas, there result an apical, two cingular and one or two antapical pericoels. Alternatively the pericoels may be united when the endocyst and pericyst are separated by a single ambital pericoel.
Periphragm: Thin (usually less than 2 μm) and of a constant thickness. Surface ornamented with parasutural granules, septa and/or processes. Intratabular ornamentation reduced or absent.
Endophragm: <1 µm to several μm thick. Surface laevigate to granulate.
Pericyst: The parasutures deIineate a typical peridinioid paratabulation of 4`, 3a, 7``, 5```, 2```` plus sulcals. In the apical series, paraplate 1` is pentagonal, 2`, 3` and 4` are considerably smaller. The 1 a and 3a paraplates appear to be pentagonal and extend closer to the pericingulum than the quadra 2a. Of the precingulars 1" and 7`` are rhomboidal with their longest axis parallel to the pericingulum, 2`` and 6`` are elongate narrow, 3`` and 5`` are four-sided, and 4`` is six-sided with its longest axis parallel to the pericingulum. The width of the 4`` is greater than that of 2a. The postcingular paraplates consist of 1``` and 5``` which are four-sided and of more or less equal size, 2``` and 4``` which are likewise four-sided and of equal size, and the distinctive pentagonal 3```. The two large antapicals are located primarily on the dorsal surface and are more or less equal in size.
Pericingulum: Produced into two pericingular horns. Delineated by parasutural ornamentation, or apparently penetabular ornamentation as linearfeatures. Commonly indented as can be seen at the distal extremity of the pericingular horns. Slightly helicoidal.
Perisulcus: Clearly delineated. Large on both epipericyst and hypopericyst. Widening posteriorly and extending onto the antapical horns. The largest paraplate is the posterior sulcal. Flagellar pore imprints occasionally visible.
Endocyst: Paratabalation indeterminate other than in the vicinity of the endoarcheopyle.
Periarcheopyle: Quadra intercalary resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. Perioperculum free or remaining attached along the anterior parasuture.
Endoarcheopyle: Quadra intercalary resulting from the loss of the second anterior intercalary paraplate 2a. Operculum usually free. May be of greater width than the periarcheopyle.
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Modified description:
Stover and Evitt, 1978, p. 133:
Synopsis:
Cysts proximate to proximochorate, circumcavate, compressed peridinioid, typically with one apical, two lateral, and two antapical horns, of which some may be reduced or absent; paratabulation peridiniacean, quadra style, expressed on periphragm by parasutural arrangement of (1) spines or processes that may arise from low ridges, or (2) other features of low relief; archeopyle intercalary, Type l/l.
Description:
Shape: Compressed peridinioid; apical, typically with one apical, two lateral, and two antapical horns, of which some may be reduced or absent.
Wall relationships: Cysts circumcavate; endocyst outline subcircular to broadly elliptical.
Wall features: Periphragm with features of low relief (e.g., granulae and coni), spines or processes in parasutural rows; spines or processes may arise from low ridges or folds. Periphragm between parasutural features smooth to faintly ornamented.
Paratabulation: Indicated by parasutural features; peridiniacean, quadrastyle, formula:4`, 3a, 7", Xc, 5"`, 2"", 0-1s; complete paratabulation not always expressed.
Archeopyle: Intercalary, Type l/l (2a only); operculum free.
Paracingulum: Indicated by one or two transverse rows of parasutural features; position may be emphasized by lateral horns.
Parasulcus: Not indicated, or expressed as a poorly delimited shallow depression mainly on the hypocyst; flagellar scar may be present.
Size: Intermediate to large.
Affinities:
Wilsonidium differs from Wetzeliella and Kisselovia in that its paratabulation is expressed by parasutural features rather than having intratabular or nontabular features.
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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.
Wilsonidium, Lentin and Williams, 1976. Diagnosis from Lentin and Williams (1976, p.138-139). Pericyst ambitus rhomboidal to pentagonal (peridinioid). Apex rounded or more commonly prolonged into an apical horn. Two equal precingular horns usually present, occasionally reduced or absent. Antapex prolonged into one eccentrically located antapical horn, the left, or two unequal symmetrically located antapical horns, the left always being the longer, the right being reduced or vestigial. From the position of the pericingular horns, the epipericyst and hypopericyst may be equal in size, or unequal, in which case the hypopericyst is always the larger. Compression dorso-ventral, usually extreme. Endocyst ambitus circular to ovoidal to ellipsoidal. Rarely may be completely appressed to the pericyst when it has the same shape. Generally only partially in contact with the pericyst and then in the interhorn areas. Compression dorso-ventral. Pericoels. When the endocyst and pericyst are in contact in the interhorn areas, there result an apical, two cingular and one or two antapical pericoels. Alternatively the pericoels may be united when the endocyst and pericyst are separated by a single ambital pericoel. Periphragm thin (usually less than 2 μm) and of a constant thickness. Surface ornamented with parasutural granules, septa, and or processes. Intratabular ornamentation reduced or absent. Endophragm less than 1 μm to several microns thick. Surface laevigate to granulate. Paratabulation. Pericyst. The parasutures delineate a typical peridinioid paratabulation of 4`, 3a, 7", 5"' . 2"'' , plus sulcals. In the apical series, paraplate 1` is pentagonal, 2`, 3` and 4` are considerably smaller. The 1a and 3a paraplates appear to be pentagonal and extend closer to the paracingulum than the quadra 2a. Of the precingulars 1" and 7" are rhomboidal with their longest axis parallel to the pericingulum, 2" and 6" are elongate narrow, 3" and 5" are four-sided, and 4" is six-sided with its longest axis parallel to the pericingulum. The width of the 4" is greater than that of 2a. The postcingular paraplates consist of 1"' and 5"' which are four-sided and of more or less equal size, 2"' and 4"' which are likewise four-sided and of equal size, and the distinctive pentagonal 3"'. The two large antapicals are located primarily on the dorsal surface and are more or less equal in size. Pericingulum is produced into two pericingular horns. Delineated by parasutural ornamentation, or apparently penitabular ornamentation as linear features. Commonly indented as can be seen at the distal extremity of the pericingular horns. Slightly helicoidal. Perisulcus clearly delineated. Large on both epipericyst and hypopericyst. Widening posteriorly and extending onto the antapical horns. The largest paraplate is the posterior sulcal. Flagellar pore imprints occasionally visible. Endocyst paratabulation indeterminate other than in the vicinity of the endoarcheopyle. Periarcheopyle quadra intercalary resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. Perioperculum free or remaining attached along the anterior parasuture. Endoarcheopyle quadra intercalary resulting from the loss of the second anterior intercalary paraplate 2a. Operculum free. May be of greater width than the periarcheopyle.
Dimensions: Pericyst length 50-171 µm, width 50-156 µm. Endocyst length 50-99 µm, width 50-102 µm.
[Wilsonidium, Lentin and Williams, 1976, p.138–139; Emendation: Williams et al., 2015, p. 318.
Type species: as Wetzeliella tabulata, Wilson, 1967c (figs.4–6)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Lentin and Williams, 1976]:
Description:
Pericyst: Ambitus rhomboidal to pentagonal (peridinioid). Apex rounded or more commonly prolonged into an apical horn. Two equal precingular horns usually present, occasionally reduced or absent. Antapex prolonged into one eccentrically located antapical horn, the left, or two unequal symmetrically located antapical horns, the left always being the longer, the right being reduced or vestigial. From the position of the pericingular horns, the epipericyst and hypopericyst may be equal in size, or unequal, in which case the hypopericyst is always the larger. Compression dorso-ventral, usually extreme.
Endocyst: Ambitus circular to ovoidal to ellipsoidal. Rarely may be completely appressed to the pericyst when it has the same shape. Generally only partially in contact with the pericyst and then in the interhorn areas. Compression dorso-ventral.
Pericoels: When the endocyst and pericyst are in contact in the interhorn areas, there result an apical, two cingular and one or two antapical pericoels. Alternatively the pericoels may be united when the endocyst and pericyst are separated by a single ambital pericoel.
Periphragm: Thin (usually less than 2 μm) and of a constant thickness. Surface ornamented with parasutural granules, septa and/or processes. Intratabular ornamentation reduced or absent.
Endophragm: <1 µm to several μm thick. Surface laevigate to granulate.
Pericyst: The parasutures deIineate a typical peridinioid paratabulation of 4`, 3a, 7``, 5```, 2```` plus sulcals. In the apical series, paraplate 1` is pentagonal, 2`, 3` and 4` are considerably smaller. The 1 a and 3a paraplates appear to be pentagonal and extend closer to the pericingulum than the quadra 2a. Of the precingulars 1" and 7`` are rhomboidal with their longest axis parallel to the pericingulum, 2`` and 6`` are elongate narrow, 3`` and 5`` are four-sided, and 4`` is six-sided with its longest axis parallel to the pericingulum. The width of the 4`` is greater than that of 2a. The postcingular paraplates consist of 1``` and 5``` which are four-sided and of more or less equal size, 2``` and 4``` which are likewise four-sided and of equal size, and the distinctive pentagonal 3```. The two large antapicals are located primarily on the dorsal surface and are more or less equal in size.
Pericingulum: Produced into two pericingular horns. Delineated by parasutural ornamentation, or apparently penetabular ornamentation as linearfeatures. Commonly indented as can be seen at the distal extremity of the pericingular horns. Slightly helicoidal.
Perisulcus: Clearly delineated. Large on both epipericyst and hypopericyst. Widening posteriorly and extending onto the antapical horns. The largest paraplate is the posterior sulcal. Flagellar pore imprints occasionally visible.
Endocyst: Paratabalation indeterminate other than in the vicinity of the endoarcheopyle.
Periarcheopyle: Quadra intercalary resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. Perioperculum free or remaining attached along the anterior parasuture.
Endoarcheopyle: Quadra intercalary resulting from the loss of the second anterior intercalary paraplate 2a. Operculum usually free. May be of greater width than the periarcheopyle.
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Modified description:
Stover and Evitt, 1978, p. 133:
Synopsis:
Cysts proximate to proximochorate, circumcavate, compressed peridinioid, typically with one apical, two lateral, and two antapical horns, of which some may be reduced or absent; paratabulation peridiniacean, quadra style, expressed on periphragm by parasutural arrangement of (1) spines or processes that may arise from low ridges, or (2) other features of low relief; archeopyle intercalary, Type l/l.
Description:
Shape: Compressed peridinioid; apical, typically with one apical, two lateral, and two antapical horns, of which some may be reduced or absent.
Wall relationships: Cysts circumcavate; endocyst outline subcircular to broadly elliptical.
Wall features: Periphragm with features of low relief (e.g., granulae and coni), spines or processes in parasutural rows; spines or processes may arise from low ridges or folds. Periphragm between parasutural features smooth to faintly ornamented.
Paratabulation: Indicated by parasutural features; peridiniacean, quadrastyle, formula:4`, 3a, 7", Xc, 5"`, 2"", 0-1s; complete paratabulation not always expressed.
Archeopyle: Intercalary, Type l/l (2a only); operculum free.
Paracingulum: Indicated by one or two transverse rows of parasutural features; position may be emphasized by lateral horns.
Parasulcus: Not indicated, or expressed as a poorly delimited shallow depression mainly on the hypocyst; flagellar scar may be present.
Size: Intermediate to large.
Affinities:
Wilsonidium differs from Wetzeliella and Kisselovia in that its paratabulation is expressed by parasutural features rather than having intratabular or nontabular features.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Wilsonidium, Lentin and Williams, 1976. Diagnosis from Lentin and Williams (1976, p.138-139). Pericyst ambitus rhomboidal to pentagonal (peridinioid). Apex rounded or more commonly prolonged into an apical horn. Two equal precingular horns usually present, occasionally reduced or absent. Antapex prolonged into one eccentrically located antapical horn, the left, or two unequal symmetrically located antapical horns, the left always being the longer, the right being reduced or vestigial. From the position of the pericingular horns, the epipericyst and hypopericyst may be equal in size, or unequal, in which case the hypopericyst is always the larger. Compression dorso-ventral, usually extreme. Endocyst ambitus circular to ovoidal to ellipsoidal. Rarely may be completely appressed to the pericyst when it has the same shape. Generally only partially in contact with the pericyst and then in the interhorn areas. Compression dorso-ventral. Pericoels. When the endocyst and pericyst are in contact in the interhorn areas, there result an apical, two cingular and one or two antapical pericoels. Alternatively the pericoels may be united when the endocyst and pericyst are separated by a single ambital pericoel. Periphragm thin (usually less than 2 μm) and of a constant thickness. Surface ornamented with parasutural granules, septa, and or processes. Intratabular ornamentation reduced or absent. Endophragm less than 1 μm to several microns thick. Surface laevigate to granulate. Paratabulation. Pericyst. The parasutures delineate a typical peridinioid paratabulation of 4`, 3a, 7", 5"' . 2"'' , plus sulcals. In the apical series, paraplate 1` is pentagonal, 2`, 3` and 4` are considerably smaller. The 1a and 3a paraplates appear to be pentagonal and extend closer to the paracingulum than the quadra 2a. Of the precingulars 1" and 7" are rhomboidal with their longest axis parallel to the pericingulum, 2" and 6" are elongate narrow, 3" and 5" are four-sided, and 4" is six-sided with its longest axis parallel to the pericingulum. The width of the 4" is greater than that of 2a. The postcingular paraplates consist of 1"' and 5"' which are four-sided and of more or less equal size, 2"' and 4"' which are likewise four-sided and of equal size, and the distinctive pentagonal 3"'. The two large antapicals are located primarily on the dorsal surface and are more or less equal in size. Pericingulum is produced into two pericingular horns. Delineated by parasutural ornamentation, or apparently penitabular ornamentation as linear features. Commonly indented as can be seen at the distal extremity of the pericingular horns. Slightly helicoidal. Perisulcus clearly delineated. Large on both epipericyst and hypopericyst. Widening posteriorly and extending onto the antapical horns. The largest paraplate is the posterior sulcal. Flagellar pore imprints occasionally visible. Endocyst paratabulation indeterminate other than in the vicinity of the endoarcheopyle. Periarcheopyle quadra intercalary resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. Perioperculum free or remaining attached along the anterior parasuture. Endoarcheopyle quadra intercalary resulting from the loss of the second anterior intercalary paraplate 2a. Operculum free. May be of greater width than the periarcheopyle.
Dimensions: Pericyst length 50-171 µm, width 50-156 µm. Endocyst length 50-99 µm, width 50-102 µm.