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Acanthaulax granulata
Acanthaulax granulata, (Klement, 1960), Brenner, 1988; Emendation as Meristaulax granulata: Sarjeant, 1984a, p. 161-162
NOW Cribroperidinium. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly (and now) Cribroperidinium, fourthly Rhynchodiniopsis, fifthly Meristaulax Sarjeant, sixthly Acanthaulax.
Poulsen (1996, p.73) retained this species in Cribroperidinium.
Tax. jr. syn.: Gonyaulax (as Cribroperidinium) venusta, according to Schrank (2005, p.56); Gonyaulax (now Cribroperidinium) granuligera, according to Fisher and Riley (1980, p.321) — however, Sarjeant (1984a, p.156–158) retained Gonyaulax (as Cryptarchaeodinium) granuligera; Gonyaulacysta (as Acanthaulax?, now Cribroperidinium) angulosa, according to Fisher and Riley (1980, p.321) — however, Sarjeant and Gocht in Sarjeant (1984a, p.160) retained Gonyaulacysta (as Meristaulax) angulosa.
For further discussion, see Cribroperidinium granulatum.
Holotype: Klement, 1960, pl.4, figs.10–11; text-figs.18–20; Fensome et al., 1995, figs.1–2 — p.1525; disintegrated according to Sarjeant (1984a, p.162).
Lectotype (designated by Sarjeant, 1984a, p.162): Sarjeant, 1984a, pl.3, figs.3–4; text-fig.3; Jan du Chêne et al., 1986a, pl.27, figs.7–10; Brenner, 1988, pl.3, figs.2a–b; Fensome et al., 1995, figs.5–6 — p.1525 — however, Brenner (1988, p.35) argued that this specimen is not conspecific with the holotype.
Lectotype (designated by Brenner, 1988, p.35): Brenner, 1988, pl.1, figs.3a–c; Fensome et al., 1995, figs.7–9 — p.1525.
Age: middle Oxfordian–early Kimmeridgian.
Locus typicus: Borehole Scherstetten 1
Stratum typicum: Malm-Lower Delta
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Original description as Gonyaulax granulata: [Klement 1960, p. 39] (Translation: GSC):
Diagnosis:
A species of the genus Gonyaulax with the following tabulation scheme: 4', 6'', 6''', 1p. 1ppl. 1''''. Envelope is of a spheroidal to thick-set egg-shaped form, with plates which display pronounced convex curvatures. Protuberance on apex is not always fully developed; at times, only a thin, solid process shows up on the apex, whereas at other times 3-4 isolated filaments are visible. Sutures range from being granulated to being tuberculated, at times, they are covered with fine spines. The surface of the plates ranges from being granulated to being covered with spines. The appearance on the plates of parallel suture "duplications" is actually due to the linear, uniform arrangement of tubercles on the surface plates. Girdle furrow is of helicoidal shape, it is displaced distally by about 1.5 to 2.5 times its own width, and is noticeably indented. Longitudinal furrow extends from the 1st. apical to the antapex.
Description:
The present type embodies one of the variable Gonyaulax species, in the case of which an ornamentation of the sutures, through longer furcation-branches or through superimposed broad combs and lists, is missing. Without any exceptions, the thecas -- which ranged from possessing a spheroidal to thick-set - ovaloidal shape, were preserved in a completely three-dimensional state, which enabled us to study the structural characteristics in great detail.
The plates, which display pronounced convex curvatures, possess a surface which ranges from being finely granulated to being covered, on rarer occasions, by low tubercles and, in part, by short, fine spines. The sutures are likewise built-up of rows of individual tubercules lying close to one another, whereby - in analogous manner - said tubercles can develop into numerous, short fine spines. This can be seen particularly will in the optical median cross-section; here we find specimens with an almost smooth contour, next to those displaying a contour which is covered with fine spines. What seems noteworthy here, is a particular type of ornamentation of the plates, reminding one of the plate ornamentation discovered by DEFLANDRE in the case of the Gonyaulax pachyderma. This plate ornamentation consists therein that more or less distinct, parallel suture "duplications" occur on the plates, which had been created by a linear arrangement of the granulation. The phenomenon which shows up regularly and proved to be particularly characteristic in this connection, is the repetition of the sutures between plates 1'''', 2''' and 3'''; this gives the impression as if one was dealing with a parallel shifting of the suture system with a small horizontal displacement distance; the same can be said for the dorsal postequatorial plates in which the displacement involves, in each case, two trapezoids which become concentrically telescoped. For this reason we have to be careful and distinguish in each case between the true sutures (which, as a rule, are somewhat thicker than the suture "duplications") and the peculiar repetition of the sutures on the plates (referred to as suture "duplications").
The apex is formed by four plates, of which plate 1' is especially elongated and lies as a direct extension of the longitudinal furrow and is furthermore adjacent to plate 4'. However, plates 2' and 3' lie dorsally and have a trapeze-like shape. Particularly in the case of thick-set - ovaloidal representatives, the apical plates can be drawn upwardly in slightly angular manner. An apex - protuberance is not always present. In some specimens, we found a short, thin solid horn with a three-fold distal tuberculation. However, in other instances, this [apical] horn is replaced by a structure consisting of three to four isolated processes which stand close to one another.
Of the 6 pre-cingular plates, plates 2'', 3'' and 4'' have a trapezium-like contour, whereas plates 1'', 5'' and 6'' have a trapezoidal shape. In nearly all representatives, a pylome is found in place of plate 3''.
The girdle furrow (of an average width of 4-5 microns) takes a helocoidal course and, in the case of the spherical types, is displaced distally 1.5 times its own width and, in the case of the egg-shaped representatives, is displaced distally 2.5 times its own width. This girdle furrow is noticeably indented and is likewise bordered by low, tuberculated lists.
The longitudinal furrow extends from the 1st. apical plate to the antapex and it becomes wider on the hypovalva. In part, an intercalary lower plate could be observed.
The hypotheca is formed by 6 post-cingular plates, as well as by an accessory plate (1p) and by a polygonal, convex antapical plate. Of these post-cingular plates, plate 1''' is greatly reduced and can easily be overlooked; plate 2''', likewise, has not as yet attained full growth and shows the contour of a spherical triangle.
In the case of the spherical representatives, both epitheca and hypotheca are almost of the same order of magnitude; however, the thick-set - ovaloidal representatives possess a slightly elongated hypotheca with a semi-ovaloidal contour.
The basic colour of the membrane is light yellow; however, due to the darker granulation, the membrane gives the overall impression as being of a more dark brown coloration. We found two specimens with a distinct, small-meshed reticulation of the envelope.
Relationships:
The closest related form is the species Gonyaulax granuligera (note: now Acanthaulax granuligera). Differentiating criteria are here the general habitus of the theca and the manner in which the apex proturberance is developed, with the latter being characterized by an elongated - polyhedral shape with conical transition of the epitheca to a thick horn which is formed by four upwardly drawn apical plates. Great differences separate G. granulata n.sp. from the G. pachyderma DEFLANDRE, which shows analogous linear structures on the plates, with said structures running parallel to the sutures. With the G.ambigua DEFLANDRE the present form has the following in common, namely the granulation of the plates and of the sutures, however, in the case of the G.ambigua DEFLANDRE the suture -"duplications" and the spine coverage, which are so very characteristic for the present form, are never mentioned. Furthermore, differences exist with respect to the arrangement of the ventral tabulation of the hypovalva, as - on the whole - in the coverage of the sutures which, in the case of the G. ambigua DEFLANDRE, consists of low lists, whereas here it consists more of striation-like thickenings.
NOW Cribroperidinium. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly (and now) Cribroperidinium, fourthly Rhynchodiniopsis, fifthly Meristaulax Sarjeant, sixthly Acanthaulax.
Poulsen (1996, p.73) retained this species in Cribroperidinium.
Tax. jr. syn.: Gonyaulax (as Cribroperidinium) venusta, according to Schrank (2005, p.56); Gonyaulax (now Cribroperidinium) granuligera, according to Fisher and Riley (1980, p.321) — however, Sarjeant (1984a, p.156–158) retained Gonyaulax (as Cryptarchaeodinium) granuligera; Gonyaulacysta (as Acanthaulax?, now Cribroperidinium) angulosa, according to Fisher and Riley (1980, p.321) — however, Sarjeant and Gocht in Sarjeant (1984a, p.160) retained Gonyaulacysta (as Meristaulax) angulosa.
For further discussion, see Cribroperidinium granulatum.
Holotype: Klement, 1960, pl.4, figs.10–11; text-figs.18–20; Fensome et al., 1995, figs.1–2 — p.1525; disintegrated according to Sarjeant (1984a, p.162).
Lectotype (designated by Sarjeant, 1984a, p.162): Sarjeant, 1984a, pl.3, figs.3–4; text-fig.3; Jan du Chêne et al., 1986a, pl.27, figs.7–10; Brenner, 1988, pl.3, figs.2a–b; Fensome et al., 1995, figs.5–6 — p.1525 — however, Brenner (1988, p.35) argued that this specimen is not conspecific with the holotype.
Lectotype (designated by Brenner, 1988, p.35): Brenner, 1988, pl.1, figs.3a–c; Fensome et al., 1995, figs.7–9 — p.1525.
Age: middle Oxfordian–early Kimmeridgian.
Locus typicus: Borehole Scherstetten 1
Stratum typicum: Malm-Lower Delta
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Original description as Gonyaulax granulata: [Klement 1960, p. 39] (Translation: GSC):
Diagnosis:
A species of the genus Gonyaulax with the following tabulation scheme: 4', 6'', 6''', 1p. 1ppl. 1''''. Envelope is of a spheroidal to thick-set egg-shaped form, with plates which display pronounced convex curvatures. Protuberance on apex is not always fully developed; at times, only a thin, solid process shows up on the apex, whereas at other times 3-4 isolated filaments are visible. Sutures range from being granulated to being tuberculated, at times, they are covered with fine spines. The surface of the plates ranges from being granulated to being covered with spines. The appearance on the plates of parallel suture "duplications" is actually due to the linear, uniform arrangement of tubercles on the surface plates. Girdle furrow is of helicoidal shape, it is displaced distally by about 1.5 to 2.5 times its own width, and is noticeably indented. Longitudinal furrow extends from the 1st. apical to the antapex.
Description:
The present type embodies one of the variable Gonyaulax species, in the case of which an ornamentation of the sutures, through longer furcation-branches or through superimposed broad combs and lists, is missing. Without any exceptions, the thecas -- which ranged from possessing a spheroidal to thick-set - ovaloidal shape, were preserved in a completely three-dimensional state, which enabled us to study the structural characteristics in great detail.
The plates, which display pronounced convex curvatures, possess a surface which ranges from being finely granulated to being covered, on rarer occasions, by low tubercles and, in part, by short, fine spines. The sutures are likewise built-up of rows of individual tubercules lying close to one another, whereby - in analogous manner - said tubercles can develop into numerous, short fine spines. This can be seen particularly will in the optical median cross-section; here we find specimens with an almost smooth contour, next to those displaying a contour which is covered with fine spines. What seems noteworthy here, is a particular type of ornamentation of the plates, reminding one of the plate ornamentation discovered by DEFLANDRE in the case of the Gonyaulax pachyderma. This plate ornamentation consists therein that more or less distinct, parallel suture "duplications" occur on the plates, which had been created by a linear arrangement of the granulation. The phenomenon which shows up regularly and proved to be particularly characteristic in this connection, is the repetition of the sutures between plates 1'''', 2''' and 3'''; this gives the impression as if one was dealing with a parallel shifting of the suture system with a small horizontal displacement distance; the same can be said for the dorsal postequatorial plates in which the displacement involves, in each case, two trapezoids which become concentrically telescoped. For this reason we have to be careful and distinguish in each case between the true sutures (which, as a rule, are somewhat thicker than the suture "duplications") and the peculiar repetition of the sutures on the plates (referred to as suture "duplications").
The apex is formed by four plates, of which plate 1' is especially elongated and lies as a direct extension of the longitudinal furrow and is furthermore adjacent to plate 4'. However, plates 2' and 3' lie dorsally and have a trapeze-like shape. Particularly in the case of thick-set - ovaloidal representatives, the apical plates can be drawn upwardly in slightly angular manner. An apex - protuberance is not always present. In some specimens, we found a short, thin solid horn with a three-fold distal tuberculation. However, in other instances, this [apical] horn is replaced by a structure consisting of three to four isolated processes which stand close to one another.
Of the 6 pre-cingular plates, plates 2'', 3'' and 4'' have a trapezium-like contour, whereas plates 1'', 5'' and 6'' have a trapezoidal shape. In nearly all representatives, a pylome is found in place of plate 3''.
The girdle furrow (of an average width of 4-5 microns) takes a helocoidal course and, in the case of the spherical types, is displaced distally 1.5 times its own width and, in the case of the egg-shaped representatives, is displaced distally 2.5 times its own width. This girdle furrow is noticeably indented and is likewise bordered by low, tuberculated lists.
The longitudinal furrow extends from the 1st. apical plate to the antapex and it becomes wider on the hypovalva. In part, an intercalary lower plate could be observed.
The hypotheca is formed by 6 post-cingular plates, as well as by an accessory plate (1p) and by a polygonal, convex antapical plate. Of these post-cingular plates, plate 1''' is greatly reduced and can easily be overlooked; plate 2''', likewise, has not as yet attained full growth and shows the contour of a spherical triangle.
In the case of the spherical representatives, both epitheca and hypotheca are almost of the same order of magnitude; however, the thick-set - ovaloidal representatives possess a slightly elongated hypotheca with a semi-ovaloidal contour.
The basic colour of the membrane is light yellow; however, due to the darker granulation, the membrane gives the overall impression as being of a more dark brown coloration. We found two specimens with a distinct, small-meshed reticulation of the envelope.
Relationships:
The closest related form is the species Gonyaulax granuligera (note: now Acanthaulax granuligera). Differentiating criteria are here the general habitus of the theca and the manner in which the apex proturberance is developed, with the latter being characterized by an elongated - polyhedral shape with conical transition of the epitheca to a thick horn which is formed by four upwardly drawn apical plates. Great differences separate G. granulata n.sp. from the G. pachyderma DEFLANDRE, which shows analogous linear structures on the plates, with said structures running parallel to the sutures. With the G.ambigua DEFLANDRE the present form has the following in common, namely the granulation of the plates and of the sutures, however, in the case of the G.ambigua DEFLANDRE the suture -"duplications" and the spine coverage, which are so very characteristic for the present form, are never mentioned. Furthermore, differences exist with respect to the arrangement of the ventral tabulation of the hypovalva, as - on the whole - in the coverage of the sutures which, in the case of the G. ambigua DEFLANDRE, consists of low lists, whereas here it consists more of striation-like thickenings.