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Acanthaulax granuligera
Acanthaulax granuligera, (Klement, 1960, p. 41-42, pl. 5, figs. 4-5), Brenner, 1988, p. 35-36; Emendation as Cryptarchaeodinium granuligerum: Sarjeant, 1984a, p.156.
NOW Cribroperidinium. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly (and now) Cribroperidinium, fourthly Rhynchodiniopsis, fifthly Cryptarchaeodinium, sixthly Acanthaulax - however Poulsen (1996) retained this species in Cribroperidinium
Tax. sr. syn.: Gonyaulax (as Gonyaulacysta) granulata, according to Fisher and Riley (1980, p.321) - however, Sarjeant (1984a, p.156) retained Acanthaulax (as Cryptarchaeodinium) granuligera.
Holotype: Klement, 1960, pl.5, figs.4-5; Sarjeant, 1984a, pl.1, figs.3-4; text-fig.1; Jan du Chêne et al., 1986a, pl.27, figs.11-14.
Age: Mid Oxfordian-Early Kimmeridgian.
Locus typicus: Borehole Scherstetten 1
Stratum typicum: Malm-Lower Delta
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Original description as Gonyaulax granuligera: [Klement 1960, p. 41-42] (Translation: GSC):
Diagnosis:
A species of the genus Gonyaulax with the following tabulation scheme: 4'',6'',6''',1p, 1ppl, 1''''. Elongated polyhedral theca, apically developing into a thick long horn (without a constricted area being present in the transition area from theca to horn). Plates and sutures ranging from being granulated to being tuberculated. Plates frequently display parallel, granulated suture "duplications". Helicoidal girdle furrow, displaced distally about 1.5 to 2 times its won width. Longitudinal furrow extending from the 1st. apical plate to the antapex, divergently widening on the hypotheca, with intercalary lower plate.
Description:
This species, which occurs much more seldom than Gonyaulax granulata KLEMENT, differs from G. granulata by virtue of the elongated-polyhedral shape of the theca which displays a thick apical horn.
The tabulation, as well as the location and structure of the sutures and the type of ornamentation on the plates correspond in all details to those described in the case of the G.granulata n.sp. (In analogous manner, characteristic parallel suture "duplications' are present here as well).
In this species, the theca displays a slightly polygonal, elongated contour with a conically terminating epitheca which, without any construction, turns into the apical horn, namely via the four upwardly drawn apical plates. This horn appears to be relatively long and thick and was found to be hollow in its lower third portion and connected with the internal area of the cell, whereas the remaining 2/3 portion is solid. The distal extremity appears to bear a three-fold denticulation; in the case of the holotype, an additional lateral spine arises from a point located about 2/3 up on the horn.
Centrally, the plates of the theca show a shallow indentation and, toward the sutures, they are curved upwardly in an arch-like manner. This can be seen particularly well when viewing the curved upper edge of the pylome (taking the place of plate 3''), in the center of which the suture between plate 2' and plate 3' terminates, as well as when viewing the lateral boundaries of said pylome.
The helicoidal girdle furrow does not appear to be very indented; distally, its is displaced 1.5 to slightly more than 2 times its own width.
The longitudinal furrow is noticeable indented and, on the hypotheca, shows a particularly pronounced divergent widening. An intercalary lower plate could be ascertained unequivocally.
The membrane displays light yellow to brownish colorations and is finely granulated. We could not find any reticulated specimens.
Relationships:
The closest related species is G.granulata KLEMENT, see there for detailed differential-diagnosis.
NOW Cribroperidinium. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly (and now) Cribroperidinium, fourthly Rhynchodiniopsis, fifthly Cryptarchaeodinium, sixthly Acanthaulax - however Poulsen (1996) retained this species in Cribroperidinium
Tax. sr. syn.: Gonyaulax (as Gonyaulacysta) granulata, according to Fisher and Riley (1980, p.321) - however, Sarjeant (1984a, p.156) retained Acanthaulax (as Cryptarchaeodinium) granuligera.
Holotype: Klement, 1960, pl.5, figs.4-5; Sarjeant, 1984a, pl.1, figs.3-4; text-fig.1; Jan du Chêne et al., 1986a, pl.27, figs.11-14.
Age: Mid Oxfordian-Early Kimmeridgian.
Locus typicus: Borehole Scherstetten 1
Stratum typicum: Malm-Lower Delta
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Original description as Gonyaulax granuligera: [Klement 1960, p. 41-42] (Translation: GSC):
Diagnosis:
A species of the genus Gonyaulax with the following tabulation scheme: 4'',6'',6''',1p, 1ppl, 1''''. Elongated polyhedral theca, apically developing into a thick long horn (without a constricted area being present in the transition area from theca to horn). Plates and sutures ranging from being granulated to being tuberculated. Plates frequently display parallel, granulated suture "duplications". Helicoidal girdle furrow, displaced distally about 1.5 to 2 times its won width. Longitudinal furrow extending from the 1st. apical plate to the antapex, divergently widening on the hypotheca, with intercalary lower plate.
Description:
This species, which occurs much more seldom than Gonyaulax granulata KLEMENT, differs from G. granulata by virtue of the elongated-polyhedral shape of the theca which displays a thick apical horn.
The tabulation, as well as the location and structure of the sutures and the type of ornamentation on the plates correspond in all details to those described in the case of the G.granulata n.sp. (In analogous manner, characteristic parallel suture "duplications' are present here as well).
In this species, the theca displays a slightly polygonal, elongated contour with a conically terminating epitheca which, without any construction, turns into the apical horn, namely via the four upwardly drawn apical plates. This horn appears to be relatively long and thick and was found to be hollow in its lower third portion and connected with the internal area of the cell, whereas the remaining 2/3 portion is solid. The distal extremity appears to bear a three-fold denticulation; in the case of the holotype, an additional lateral spine arises from a point located about 2/3 up on the horn.
Centrally, the plates of the theca show a shallow indentation and, toward the sutures, they are curved upwardly in an arch-like manner. This can be seen particularly well when viewing the curved upper edge of the pylome (taking the place of plate 3''), in the center of which the suture between plate 2' and plate 3' terminates, as well as when viewing the lateral boundaries of said pylome.
The helicoidal girdle furrow does not appear to be very indented; distally, its is displaced 1.5 to slightly more than 2 times its own width.
The longitudinal furrow is noticeable indented and, on the hypotheca, shows a particularly pronounced divergent widening. An intercalary lower plate could be ascertained unequivocally.
The membrane displays light yellow to brownish colorations and is finely granulated. We could not find any reticulated specimens.
Relationships:
The closest related species is G.granulata KLEMENT, see there for detailed differential-diagnosis.