Back
Flamingoia cometa
Flamingoia cometa Stevens and Helby, 1987
Holotype: Stevens and Helby, 1987, fig.9A-C
Locus typicus: Eendracht-1 well, W Australia
Stratum typicum: Early Berriasian
Original description: Stevens and Helby, 1987, p.175-176
Cysts skolochorate with a subspherical, smooth autophragm, up to 1 Ám thick, and a trabeculate ectophragm. Six solid, intratabular processes 2-3 Ám in diameter and 8-28 Ám in length extending radially from supraequatorial locations. Distal tapered tip of each process inclined 3-8 Ám anteriorly from the point of emanation of a single, long (54-93 Ám in length) trabecular strand connecting with the posterior ectophragm. A 1-1.5 Ám wide sinuous process, originating subequatorially, and a robust, hollow, distally flared process (up to 70 Ám posterior diameter, 70-102 Ám long) originating from the antapex. extend posteriorly. Flared end of the antapical process merging with the base of a basket-shaped, trabeculate ectophragm, located posterior to the autocyst. Ectophragm attached anteriorly to the distal ends of the 6 radial intratabular processes interpreted as projecting from the precingular paraplate series. Ectophragm showing a consistent trabeculate pattern with major lacunae arranged in 2 subconcentric rings around the antapical process; Subconcentric arrangement apparently reflecting paraplate series, but direct paraplate analogies (Fig.8) not demonstrable. Archeopyle apical, type [tA], with a zigzag principal suture, short accessory sutures and a relatively deep sulcal notch. Archeopyle margin commonly folded and distorted, however on some specimens 6 precingular paraplates may be identified. Operculum gently convex, smooth, lacking processes, generally free but may be adherent. Isolated opercula not recognized. Paratabulation apparently gonyaulacacean, interpreted as ?4", 6"", Xc, X""", ?1p, 1"""", expressed by the archeopyle, with accessory archeopyle and opercular sutures, and intratabular processes reflecting the precingular paraplate series, the ?posterior intercalary and the antapical paraplates. Cingular, postcingular and sulcal paraplate series not evident on the autophragm, may be reflected as subconcentric rings of irregular lacunae in the trabecular pattern in the ectophragm. Position of the parasulcus on the autophragm marked by the sulcal notch (Fig.9D,H). On some specimens a suggestion of ventral offset of the paracingular lacunae reflecting the parasulcus. Measurements. Total cyst length 70-125 Ám, autocyst length (dehisced and excluding processes) 24(35)54 Ám, autocyst width 32(44)64 Ám (13 specimens). Variability. The size and shape of the cyst and of the processes are fairly constant. The points of origin of the 8 posteriorly extended processes, their relationship to the trabeculation and the trabeculation pattern itself, appear to be consistent features. The archeopyle margin is commonly folded, obscuring its zigzag principal suture and the sulcal notch (Fig.9B,C,E). The operculum is generally free but may be adherent (Fig.9G,J) and is always without processes or ectophragm. The thin autophragm, the narrow processes and the trabeculae are commonly folded, broken and distorted (Fig.9F).
Paratabulation: The paratabulation expressed above is our interpretation from the specimens available. We are uncertain about several features. Specifically, the anterior processes are interpreted as originating from the precingular paraplates due to their supraequatorial location and the possibility that the anterior row of lacunae in the ectophragm may represent the paracingulum. However, these processes might be interpreted as arising from the cingular paraplates. In addition, the narrow process arising from a posterior location on the autocyst is interpreted as an intratabular, posterior intercalary (lp) process. Alternatively, this process might be interpreted as arising from a sulcal (?ms or ps) paraplate. Although we have examined several adherent opercula it has not been possible to determine the number of apical paraplates in these opercula. Our interpretation of 4 paraplates in the apical series is based on the shape of the archeopyle margin.
Affinities:
Stover and Helby, 1987, p.176-177: Flamingoia cometa resembles 2 undescribed species which we assign to Flamingoia. Flamingoia sp. A (Fig.lOA-C) most closely resembles F. cometa, but is distinguished by the absence of the large, robust, hollow antapical process of the latter. Flamingoia sp. B (Fig. 10D-F) is smaller, lacks a large, hollow antapical process and has a substantially different trabeculate pattern on the ectophragm. Flamingoia cometa resembles Arachnodinium antarcticum Wilson & Clowes 1982 but is readily distinguished (Table 1). Flamingoia cometa resembles Palcattia cirrifera Cookson and Eisenack 1974 in having an antapical "basket-like plexus" (Cookson & Eisenack, 1974, p.74). However, in the latter species an apical "plexus" (ectophragmal protuberance) is present and the processes supporting the ectophragm in B. cirrifera are interpreted as nontabular. Hapsocysta peridictya (Eisenack & Cookson) Davey 1979 resembles F. cometa in having a reticulate ectophragm/ periphragm which appears to be posteriorly disposed in some compressions (Davey, 1979, pl.4, fig.2). Davey implied by his assignment of H.peridictya to Hapsocysta Davey 1979 that H. ceridictva has a precingular archeopyle. Rigaudella aemula (Deflandre) Below 1982, which occurs in the same samples as F. cometa, has intratabular processes emanating from each paraplate in both the precingular and postcingular series and the connecting trabeculation is essentially global.
Holotype: Stevens and Helby, 1987, fig.9A-C
Locus typicus: Eendracht-1 well, W Australia
Stratum typicum: Early Berriasian
Original description: Stevens and Helby, 1987, p.175-176
Cysts skolochorate with a subspherical, smooth autophragm, up to 1 Ám thick, and a trabeculate ectophragm. Six solid, intratabular processes 2-3 Ám in diameter and 8-28 Ám in length extending radially from supraequatorial locations. Distal tapered tip of each process inclined 3-8 Ám anteriorly from the point of emanation of a single, long (54-93 Ám in length) trabecular strand connecting with the posterior ectophragm. A 1-1.5 Ám wide sinuous process, originating subequatorially, and a robust, hollow, distally flared process (up to 70 Ám posterior diameter, 70-102 Ám long) originating from the antapex. extend posteriorly. Flared end of the antapical process merging with the base of a basket-shaped, trabeculate ectophragm, located posterior to the autocyst. Ectophragm attached anteriorly to the distal ends of the 6 radial intratabular processes interpreted as projecting from the precingular paraplate series. Ectophragm showing a consistent trabeculate pattern with major lacunae arranged in 2 subconcentric rings around the antapical process; Subconcentric arrangement apparently reflecting paraplate series, but direct paraplate analogies (Fig.8) not demonstrable. Archeopyle apical, type [tA], with a zigzag principal suture, short accessory sutures and a relatively deep sulcal notch. Archeopyle margin commonly folded and distorted, however on some specimens 6 precingular paraplates may be identified. Operculum gently convex, smooth, lacking processes, generally free but may be adherent. Isolated opercula not recognized. Paratabulation apparently gonyaulacacean, interpreted as ?4", 6"", Xc, X""", ?1p, 1"""", expressed by the archeopyle, with accessory archeopyle and opercular sutures, and intratabular processes reflecting the precingular paraplate series, the ?posterior intercalary and the antapical paraplates. Cingular, postcingular and sulcal paraplate series not evident on the autophragm, may be reflected as subconcentric rings of irregular lacunae in the trabecular pattern in the ectophragm. Position of the parasulcus on the autophragm marked by the sulcal notch (Fig.9D,H). On some specimens a suggestion of ventral offset of the paracingular lacunae reflecting the parasulcus. Measurements. Total cyst length 70-125 Ám, autocyst length (dehisced and excluding processes) 24(35)54 Ám, autocyst width 32(44)64 Ám (13 specimens). Variability. The size and shape of the cyst and of the processes are fairly constant. The points of origin of the 8 posteriorly extended processes, their relationship to the trabeculation and the trabeculation pattern itself, appear to be consistent features. The archeopyle margin is commonly folded, obscuring its zigzag principal suture and the sulcal notch (Fig.9B,C,E). The operculum is generally free but may be adherent (Fig.9G,J) and is always without processes or ectophragm. The thin autophragm, the narrow processes and the trabeculae are commonly folded, broken and distorted (Fig.9F).
Paratabulation: The paratabulation expressed above is our interpretation from the specimens available. We are uncertain about several features. Specifically, the anterior processes are interpreted as originating from the precingular paraplates due to their supraequatorial location and the possibility that the anterior row of lacunae in the ectophragm may represent the paracingulum. However, these processes might be interpreted as arising from the cingular paraplates. In addition, the narrow process arising from a posterior location on the autocyst is interpreted as an intratabular, posterior intercalary (lp) process. Alternatively, this process might be interpreted as arising from a sulcal (?ms or ps) paraplate. Although we have examined several adherent opercula it has not been possible to determine the number of apical paraplates in these opercula. Our interpretation of 4 paraplates in the apical series is based on the shape of the archeopyle margin.
Affinities:
Stover and Helby, 1987, p.176-177: Flamingoia cometa resembles 2 undescribed species which we assign to Flamingoia. Flamingoia sp. A (Fig.lOA-C) most closely resembles F. cometa, but is distinguished by the absence of the large, robust, hollow antapical process of the latter. Flamingoia sp. B (Fig. 10D-F) is smaller, lacks a large, hollow antapical process and has a substantially different trabeculate pattern on the ectophragm. Flamingoia cometa resembles Arachnodinium antarcticum Wilson & Clowes 1982 but is readily distinguished (Table 1). Flamingoia cometa resembles Palcattia cirrifera Cookson and Eisenack 1974 in having an antapical "basket-like plexus" (Cookson & Eisenack, 1974, p.74). However, in the latter species an apical "plexus" (ectophragmal protuberance) is present and the processes supporting the ectophragm in B. cirrifera are interpreted as nontabular. Hapsocysta peridictya (Eisenack & Cookson) Davey 1979 resembles F. cometa in having a reticulate ectophragm/ periphragm which appears to be posteriorly disposed in some compressions (Davey, 1979, pl.4, fig.2). Davey implied by his assignment of H.peridictya to Hapsocysta Davey 1979 that H. ceridictva has a precingular archeopyle. Rigaudella aemula (Deflandre) Below 1982, which occurs in the same samples as F. cometa, has intratabular processes emanating from each paraplate in both the precingular and postcingular series and the connecting trabeculation is essentially global.