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Leptodinium bab
Leptodinium bab (Below, 1981) Sarjeant, 1985
Now Pterodinium. Originally (and now) Pterodinium, subsequently Leptodinium.
Jan du Chêne et al., 1986, retained this species in Pterodinium Eisenack, 1958.
Holotype: Below, 1981, pl.7, figs.11a-c and Jan du Chene et al., 1986, pl.87, fig.8; Fensome et al., 1991, figs.1-3 - p.581
Paratype: Below, 1981, pl.7, figs.10a-b.
Locus typicus: Yahia ou Said, SW Morocco
Stratum typicum: Late Hauterivian
Translation Below, 1981: Fensome et al., 1991, p. 582-584
Original diagnosis: Below, 1981, p. 113: Pterodinium bab
Proximate cyst, pentagonal to elongate-oval in outline. Epicyst and hypocyst of equal size. The smooth to psilate autophragm has coarsely perforate, distally undulate or dentate septa, or appendages that are distally and proximally connected to form arcade-like structures. The height of these parasutures is approximately 1/6 of the diameter of the central body, subdividing the cyst according to the gonyaulacoid scheme 4", 6"" 6c, 6""", pc, 1"""", Xs. The hexatabulate paracingulum is strongly spirai and the parasulcus is sigmoidal. Archeopyle of type P(3"").
Original description: Below, 1981, p. 113: Pterodinium bab
The habit of the species is reminiscent of the Jurassic species Leptodinium regale Gocht 1970. However, the individual parasutural appendages have not only fused distally to form arcade-like structures but have also fused proximally. The appendages are rarely slender ([Below, 1981a] text-fig.73a). Solid, broad appendages are the rule. Increased thickening or even fusion of adjacent appendages results in irregularly and coarsely perforated ([Below, 1981a] text-fig.73a) or only finely perforated membranes ([Below, 1981a] text-fig.73c). The distal margin of the septa is undulate, notched, or has short, blunt teeth. The parasutures meet apically and form a horn that extends only slightly beyond the cyst outline.
The important features of the paratabulation scheme ([Below, 1981a] text-fig.72) are summarized as follows. Polygonal 2" and 3" and the very narrow, subparallel 1" and 4", which are of equal length and are only divided by a ridge that is often absent, constitute the apical series of paraplates. This development of the fourth apical is substantially different from that in Leptodinium regale Gocht 1970, whose 4" is shorter than 1" and is rhomboid in outline. It [4" in Leptodinium regale] extends into the deep posterior angle between 5" and the trapezoidal 6"". In Pterodinium bab n.sp., 4" is directly anterior to, and shares only a short parasuture with, a subtriangular 6". The parasulcus is neither straight nor parallel to the polar axis, as in Jurassic species of Leptodinium, but is sigmoidal. In extreme instances both ends of the strongly spiral hexatabular paracingulum occur one below the other and, thus, do not diverge horizontally. Related to this is the typical narrowing of the anterior part of the sixth precingular at the expense of the parasulcus. The parasulcus is divided longitudinally into three parts. From the posterior margin of the left end of the paracingulum, a horizontal parasuture crosses the parasulcus and meets 6". The section of the longitudinal furrow delimited in this manner is the anterior sulcal. A second parasuture bridges the parasulcus between the anterior margin of ra and the approximate centre of a very narrow 1""". It is possible that this central field contains the flagellar marks. The posterior part of the parasulcus extends to 1"""" and is usually not differentiated. The boundaries between rs and ps, rs and ls, and ps and ls are rarely indicated by fine lines.
The paraplates are either unornamented or have randomly distributed tubercles, bacula or large granules, which may number up to 10, but usually only 1-3 occur.
The archeopyle is precingular, middorsal. The operculum corresponds to paraplate 3" and is "reduced".
Now Pterodinium. Originally (and now) Pterodinium, subsequently Leptodinium.
Jan du Chêne et al., 1986, retained this species in Pterodinium Eisenack, 1958.
Holotype: Below, 1981, pl.7, figs.11a-c and Jan du Chene et al., 1986, pl.87, fig.8; Fensome et al., 1991, figs.1-3 - p.581
Paratype: Below, 1981, pl.7, figs.10a-b.
Locus typicus: Yahia ou Said, SW Morocco
Stratum typicum: Late Hauterivian
Translation Below, 1981: Fensome et al., 1991, p. 582-584
Original diagnosis: Below, 1981, p. 113: Pterodinium bab
Proximate cyst, pentagonal to elongate-oval in outline. Epicyst and hypocyst of equal size. The smooth to psilate autophragm has coarsely perforate, distally undulate or dentate septa, or appendages that are distally and proximally connected to form arcade-like structures. The height of these parasutures is approximately 1/6 of the diameter of the central body, subdividing the cyst according to the gonyaulacoid scheme 4", 6"" 6c, 6""", pc, 1"""", Xs. The hexatabulate paracingulum is strongly spirai and the parasulcus is sigmoidal. Archeopyle of type P(3"").
Original description: Below, 1981, p. 113: Pterodinium bab
The habit of the species is reminiscent of the Jurassic species Leptodinium regale Gocht 1970. However, the individual parasutural appendages have not only fused distally to form arcade-like structures but have also fused proximally. The appendages are rarely slender ([Below, 1981a] text-fig.73a). Solid, broad appendages are the rule. Increased thickening or even fusion of adjacent appendages results in irregularly and coarsely perforated ([Below, 1981a] text-fig.73a) or only finely perforated membranes ([Below, 1981a] text-fig.73c). The distal margin of the septa is undulate, notched, or has short, blunt teeth. The parasutures meet apically and form a horn that extends only slightly beyond the cyst outline.
The important features of the paratabulation scheme ([Below, 1981a] text-fig.72) are summarized as follows. Polygonal 2" and 3" and the very narrow, subparallel 1" and 4", which are of equal length and are only divided by a ridge that is often absent, constitute the apical series of paraplates. This development of the fourth apical is substantially different from that in Leptodinium regale Gocht 1970, whose 4" is shorter than 1" and is rhomboid in outline. It [4" in Leptodinium regale] extends into the deep posterior angle between 5" and the trapezoidal 6"". In Pterodinium bab n.sp., 4" is directly anterior to, and shares only a short parasuture with, a subtriangular 6". The parasulcus is neither straight nor parallel to the polar axis, as in Jurassic species of Leptodinium, but is sigmoidal. In extreme instances both ends of the strongly spiral hexatabular paracingulum occur one below the other and, thus, do not diverge horizontally. Related to this is the typical narrowing of the anterior part of the sixth precingular at the expense of the parasulcus. The parasulcus is divided longitudinally into three parts. From the posterior margin of the left end of the paracingulum, a horizontal parasuture crosses the parasulcus and meets 6". The section of the longitudinal furrow delimited in this manner is the anterior sulcal. A second parasuture bridges the parasulcus between the anterior margin of ra and the approximate centre of a very narrow 1""". It is possible that this central field contains the flagellar marks. The posterior part of the parasulcus extends to 1"""" and is usually not differentiated. The boundaries between rs and ps, rs and ls, and ps and ls are rarely indicated by fine lines.
The paraplates are either unornamented or have randomly distributed tubercles, bacula or large granules, which may number up to 10, but usually only 1-3 occur.
The archeopyle is precingular, middorsal. The operculum corresponds to paraplate 3" and is "reduced".