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Herendeenia pisciformis
Herendeenia piciformis (Cookson and Eisenack, 1958, p.61, pl.8, fig.6) Wiggins, 1969, p.146. Emendation: Stover and Helby, 1987b, p.154, as Herendeenia pisciformis, as a revised description.
Originally Omatia, subsequently (and now) Herendeenia.
Stover and Evitt, 1978, retained this species in Omatia Cookson and Eisenack, 1958. Stover and Helby, 1987, included it in Herendeenia and also provided a revised description.
Holotype: Cookson and Eisenack, 1958, pl.8, fig.6
Locus typicus: Omati, Papua
Stratum typicum: Late Jurassic
Hypotype. Wiggins 1969: (plate 1, figures 1-3).
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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.
Herendeenia pisciformis (Cookson and Eisenack, 1958) Wiggins, 1969, emend. Stover and Helby, 1987b. According to Stover and Helby (1987b, p.154), Herendeenia pisciformis has parasutural ridges or folds in the apical and antapical areas and occasionally elsewhere. The archeopyle is precingular. It has an apical projection and a truncated antapex. The two wall layers are separated near the poles, where the periphragm forms parasutural ridges or less commonly folds. Ornamentation of generally low circular, elliptical and elongate curved projections, appearing as denticulations along the edge of the wall and on the crests. Paratabulation 4', 0a, 5", xc, 5"’, 1p, 1"”. Size: length 156-180 µm, width 62-75 µm, length to width ratio 2.3-2.6.
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Original description: Cookson and Eisenack, 1958, p. 61: Omatia pisciformis
Apex of shell broadly rounded, with a short, pointed solid process which supports the outer membrane; antapex bluntly rounded. Shell membrane granular, thin outer membrane homogeneous, appearantly restricted to the apical and antapical regions. In the single specimen available a large pylome is situated to one side of the mid-line and slightly below the apex; the "lid", which is oval in outline, is partially detached. Dimensions - Holotype 142 µm long.
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Revised diagnosis: Wiigins 1969, p. 146, 148: Herendeenia pisciformis
Same as the genus with the following additional remarks. The tabulation is indistinct or
only partially discernible unless the sutures are accompanied by the finlike membrane. The difficulty in delineating this pattern increases with coarser theca ornamentation. The operculum is normally discarded, but in rare instances it can be found in place within the archeopyle, or collapsed into the central cyst. The finlike membrane surrounds the margins of the 1', 2', 3', and 1'"' plates, and extends partially along the precingular, postcingular, and posterior intercalary plate margins. Eight prominent peaks are formed by membrane juncture in the apical region, and six less prominent ones are similarly formed in the antapical region. The theca and finlike membrane surfaces are granulose, with a variable degree of coarseness.
Dimensions. Hypotype, over-all length 96 microns, width 35 microns. Over-all length 56-116 microns, width 18-40 microns, on 150 specimens measured. The average over-all length was 86 microns, and the average over-all width was 30 microns
Age and occurrence. Neocomian, probably late Hauterivian to Barremian, of unnamed Lower Cretaceous stratigraphic unit, Kamishak Hills, Alaska Peninsula, and of Herendeen Limestone, Herendeen Bay, Alaska Peninsula. Upper Jurassic of Omati, Papua, New Guinea.
Comments. The holotype is larger than any of the measured specimens from Alaska. However, size is a highly variable characteristic in this species.
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Revised description: Stover and Helby, 1987, p. 154-155
Cysts proximate, elongate ellipsoidal, with a truncated antapex as seen in dorsal-ventral view, and an apical projection formed by the periphragm. Cyst wall 1.5-2 µm thick over most of cyst, consisting of an inner unsculptured part, and an outer ornamented part; boundary between the two not always sharply differentiated. Separation of the layers occurs near the poles where periphragm forms parasutural ridges, or less commonly, folds. Ornamentation of generally low, circular, elliptical, and elongate, curved projections, appearing as denticulation along the edge of the wall and on the crests (Figs 8C,H, 10). Paratabulation formula 4', 0a, 5", Xc, 5''', 1p, 1'''' (Fig.9A,B). On the epicyst, parasutural ridges delineating 4 apical paraplates and the anterior parts of 5 precingular paraplates. Paraplates 1' and 4' on the midventral area, 4-sided, and longitudinally elongate; 1' slightly narrower than 4', and the posterior ridges of both paraplates may be aligned, or the posterior ridge of 1' may extend slightly beyond the limit of 4', or it may be undeveloped. Dorsal paraplates 2' and 3' also 4-sided, wider and shorter than 1' and 4'. Of the 5 precingular paraplates, 2' ' and 4" probably 4-sided, 3" 5-sided, and shapes of 1'' and 5" undetermined. Parasutural ridges which define the lateral boundaries of the precingular and the 5 postcingular paraplates diminish in height equatorially, leaving a broad circumcentral area without indications of paratabulation. The exact shapes of the 4 or 5 postcingular paraplates not ascertained. The 6-sided paraplate 1'''', with 3 short and 3 long sides, occupies most of the posterior ventral surface of the hypocyst. Of the 3 short sides, the middle one concave (Figs 8H,10) and interpreted as marking the posterior limit of the parasulcus; the other 2 straight, representing the boundaries between the antapical paraplate and paraplates 5''' and 1p (Fig.9A). On occasional specimens, longitudinal ridges separating paraplates 5''' and 1p from the parasulcus and the diagonal ridge between 1''' and 1p not developed. Indications of the paracingulum normally absent; those of the parasulcus limited to the hypocyst. Archeopyle precingular, type P, and formed by the release of paraplate 3"; operculum usually missing. Measurements of 12 complete specimens: length, 156-180 µm; width, 62-75 µm; the length to width ratio is 2.3-2.6. Variability. The parasutural features are longer and/or higher on some specimens. Those with the more prominent features generally reveal more of the paratabulation, and show it more clearly. Otherwise H. pisciformis shows little intraspecific variability.
Affinities:
Cookson and Eisenack, 1958, p. 61: Omatia pisciformis
Omatia pisciformis differs from O. montgomeryi principally in the homogeneous texture of the thin outer membrane. No sign of the supporting processes evident in O. montgomeryi has been observed.
Originally Omatia, subsequently (and now) Herendeenia.
Stover and Evitt, 1978, retained this species in Omatia Cookson and Eisenack, 1958. Stover and Helby, 1987, included it in Herendeenia and also provided a revised description.
Holotype: Cookson and Eisenack, 1958, pl.8, fig.6
Locus typicus: Omati, Papua
Stratum typicum: Late Jurassic
Hypotype. Wiggins 1969: (plate 1, figures 1-3).
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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.
Herendeenia pisciformis (Cookson and Eisenack, 1958) Wiggins, 1969, emend. Stover and Helby, 1987b. According to Stover and Helby (1987b, p.154), Herendeenia pisciformis has parasutural ridges or folds in the apical and antapical areas and occasionally elsewhere. The archeopyle is precingular. It has an apical projection and a truncated antapex. The two wall layers are separated near the poles, where the periphragm forms parasutural ridges or less commonly folds. Ornamentation of generally low circular, elliptical and elongate curved projections, appearing as denticulations along the edge of the wall and on the crests. Paratabulation 4', 0a, 5", xc, 5"’, 1p, 1"”. Size: length 156-180 µm, width 62-75 µm, length to width ratio 2.3-2.6.
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Original description: Cookson and Eisenack, 1958, p. 61: Omatia pisciformis
Apex of shell broadly rounded, with a short, pointed solid process which supports the outer membrane; antapex bluntly rounded. Shell membrane granular, thin outer membrane homogeneous, appearantly restricted to the apical and antapical regions. In the single specimen available a large pylome is situated to one side of the mid-line and slightly below the apex; the "lid", which is oval in outline, is partially detached. Dimensions - Holotype 142 µm long.
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Revised diagnosis: Wiigins 1969, p. 146, 148: Herendeenia pisciformis
Same as the genus with the following additional remarks. The tabulation is indistinct or
only partially discernible unless the sutures are accompanied by the finlike membrane. The difficulty in delineating this pattern increases with coarser theca ornamentation. The operculum is normally discarded, but in rare instances it can be found in place within the archeopyle, or collapsed into the central cyst. The finlike membrane surrounds the margins of the 1', 2', 3', and 1'"' plates, and extends partially along the precingular, postcingular, and posterior intercalary plate margins. Eight prominent peaks are formed by membrane juncture in the apical region, and six less prominent ones are similarly formed in the antapical region. The theca and finlike membrane surfaces are granulose, with a variable degree of coarseness.
Dimensions. Hypotype, over-all length 96 microns, width 35 microns. Over-all length 56-116 microns, width 18-40 microns, on 150 specimens measured. The average over-all length was 86 microns, and the average over-all width was 30 microns
Age and occurrence. Neocomian, probably late Hauterivian to Barremian, of unnamed Lower Cretaceous stratigraphic unit, Kamishak Hills, Alaska Peninsula, and of Herendeen Limestone, Herendeen Bay, Alaska Peninsula. Upper Jurassic of Omati, Papua, New Guinea.
Comments. The holotype is larger than any of the measured specimens from Alaska. However, size is a highly variable characteristic in this species.
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Revised description: Stover and Helby, 1987, p. 154-155
Cysts proximate, elongate ellipsoidal, with a truncated antapex as seen in dorsal-ventral view, and an apical projection formed by the periphragm. Cyst wall 1.5-2 µm thick over most of cyst, consisting of an inner unsculptured part, and an outer ornamented part; boundary between the two not always sharply differentiated. Separation of the layers occurs near the poles where periphragm forms parasutural ridges, or less commonly, folds. Ornamentation of generally low, circular, elliptical, and elongate, curved projections, appearing as denticulation along the edge of the wall and on the crests (Figs 8C,H, 10). Paratabulation formula 4', 0a, 5", Xc, 5''', 1p, 1'''' (Fig.9A,B). On the epicyst, parasutural ridges delineating 4 apical paraplates and the anterior parts of 5 precingular paraplates. Paraplates 1' and 4' on the midventral area, 4-sided, and longitudinally elongate; 1' slightly narrower than 4', and the posterior ridges of both paraplates may be aligned, or the posterior ridge of 1' may extend slightly beyond the limit of 4', or it may be undeveloped. Dorsal paraplates 2' and 3' also 4-sided, wider and shorter than 1' and 4'. Of the 5 precingular paraplates, 2' ' and 4" probably 4-sided, 3" 5-sided, and shapes of 1'' and 5" undetermined. Parasutural ridges which define the lateral boundaries of the precingular and the 5 postcingular paraplates diminish in height equatorially, leaving a broad circumcentral area without indications of paratabulation. The exact shapes of the 4 or 5 postcingular paraplates not ascertained. The 6-sided paraplate 1'''', with 3 short and 3 long sides, occupies most of the posterior ventral surface of the hypocyst. Of the 3 short sides, the middle one concave (Figs 8H,10) and interpreted as marking the posterior limit of the parasulcus; the other 2 straight, representing the boundaries between the antapical paraplate and paraplates 5''' and 1p (Fig.9A). On occasional specimens, longitudinal ridges separating paraplates 5''' and 1p from the parasulcus and the diagonal ridge between 1''' and 1p not developed. Indications of the paracingulum normally absent; those of the parasulcus limited to the hypocyst. Archeopyle precingular, type P, and formed by the release of paraplate 3"; operculum usually missing. Measurements of 12 complete specimens: length, 156-180 µm; width, 62-75 µm; the length to width ratio is 2.3-2.6. Variability. The parasutural features are longer and/or higher on some specimens. Those with the more prominent features generally reveal more of the paratabulation, and show it more clearly. Otherwise H. pisciformis shows little intraspecific variability.
Affinities:
Cookson and Eisenack, 1958, p. 61: Omatia pisciformis
Omatia pisciformis differs from O. montgomeryi principally in the homogeneous texture of the thin outer membrane. No sign of the supporting processes evident in O. montgomeryi has been observed.