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Gonyaulax venusta
Gonyaulax venusta Klement, 1960
Taxonomic senior synonym: Gonyaulax (as Cribroperidinium) granulata, according to Schrank (2005, p.56).
NOW Cribroperidinium. Originally Gonyaulax, subsequently Acanthogonyaulax (combination not validly published), thirdly Acanthaulax, fourthly Gonyaulacysta, fifthly (and now) Cribroperidinium.
Possible tax. jr. synonym of Cribroperidinium granulatum (Klement, 1960) Stover and Evitt, 1978, according to Helenes, 1984. Jan du Chêne et al., 1986, retained Acanthaulax venusta as a separate species.
Holotype: Klement, 1960, pl.5, figs.10-11
Age: Middle Oxfordian-Kimmeridgian
Original diagnosis: Klement 1960, p.44-45: Gonyaulax venusta
A species of the genus Gonyaulax, possessing the following tanualtion scheme: 4', 6'', 6''', 1p, 1''''. Sheroidal to thick-set-ovaloidal theca, apically displaying a thin proturberance, which is either solid or consists of three filamentous processess which stand close to one another. Plates are covered with closely spaced, short spines. Sutures are thickened in a striation-like manner, they are granulated and are likewise covered with short spines. The helicoidal girdle furrow is shallow and, distally, displaced one to two times its on width. Longitudinal furrow extends from the 1st. apical plate to the antapex.
Description: Klement 1960, p. 44-45: Gonyaulax venusta
This species, which - likewise - does not occur very frequently, has a sharp ranging from being spheroidal to thick-set-ovaloidal. The plates are definitely convex; they are covered with closely spaced, short spines which, distally, terminate in a knobular manner. It is for this reason that, when viewed from the top, one gains the impression of viewing a surface which is considerably punctated. On the sutures (which are thickened in straition-like manner), we also find short spines displaying the aforementioned knobular terminations.
The epitheca is made up of 4 apical plates and 6 precingular plates which, in form and arrangement, coorespond to the plates of the precedingly described species (note: Gonyaulax aculeata). As apex proturberance, we find three isolated, closely spaced , filamentous processess or a single process which is somewhat thicker.
The helocoidal girdle furrow has a width of about 4-5 microns and is displaces distally 1.5 to 2 times its own width; furthermore, it is not very much indented. What is noteworthy here is the fact that the girdle furrow is likewise covered with spines and, thus, has a punctuated appearance. However, the longitudinal furrow (which extends from the 1st. apical plate to the antapex), is mostly not covered by spines.
The hypotheca consists of 6 postcingular plates, of one accessory plate (1p) and of one polygonal, convex antapical plate. Here agian, plate 1''' is greatly reduced, and plate 2''' likewise has not as yet reached the normal size of the remaining postequatorial plates.
The range of variations of this species is of a small order of magnitude and is limited to slight deviations from the spherical shape of the envelope anf to different lengths of the spines located on plates and sutures; however, even in the extreme case, these spines can not attian lenghts of more than 4 microns.
The membrane apperas to be have a light yellow coloration, however, due to the spine coverage, gives an overall appearance of being somewhat darker.
Relationships: This species differs from the G. aculeata in that the plates display here a dense and isoalted spine-coverage (whereas in the case of G. aculeata the plates are ornemented with vermicular, low tubercle seams); a further criterium is the fact that the granualted sutures, which are developed in a striation-like manner, are not very prominent here.
Taxonomic senior synonym: Gonyaulax (as Cribroperidinium) granulata, according to Schrank (2005, p.56).
NOW Cribroperidinium. Originally Gonyaulax, subsequently Acanthogonyaulax (combination not validly published), thirdly Acanthaulax, fourthly Gonyaulacysta, fifthly (and now) Cribroperidinium.
Possible tax. jr. synonym of Cribroperidinium granulatum (Klement, 1960) Stover and Evitt, 1978, according to Helenes, 1984. Jan du Chêne et al., 1986, retained Acanthaulax venusta as a separate species.
Holotype: Klement, 1960, pl.5, figs.10-11
Age: Middle Oxfordian-Kimmeridgian
Original diagnosis: Klement 1960, p.44-45: Gonyaulax venusta
A species of the genus Gonyaulax, possessing the following tanualtion scheme: 4', 6'', 6''', 1p, 1''''. Sheroidal to thick-set-ovaloidal theca, apically displaying a thin proturberance, which is either solid or consists of three filamentous processess which stand close to one another. Plates are covered with closely spaced, short spines. Sutures are thickened in a striation-like manner, they are granulated and are likewise covered with short spines. The helicoidal girdle furrow is shallow and, distally, displaced one to two times its on width. Longitudinal furrow extends from the 1st. apical plate to the antapex.
Description: Klement 1960, p. 44-45: Gonyaulax venusta
This species, which - likewise - does not occur very frequently, has a sharp ranging from being spheroidal to thick-set-ovaloidal. The plates are definitely convex; they are covered with closely spaced, short spines which, distally, terminate in a knobular manner. It is for this reason that, when viewed from the top, one gains the impression of viewing a surface which is considerably punctated. On the sutures (which are thickened in straition-like manner), we also find short spines displaying the aforementioned knobular terminations.
The epitheca is made up of 4 apical plates and 6 precingular plates which, in form and arrangement, coorespond to the plates of the precedingly described species (note: Gonyaulax aculeata). As apex proturberance, we find three isolated, closely spaced , filamentous processess or a single process which is somewhat thicker.
The helocoidal girdle furrow has a width of about 4-5 microns and is displaces distally 1.5 to 2 times its own width; furthermore, it is not very much indented. What is noteworthy here is the fact that the girdle furrow is likewise covered with spines and, thus, has a punctuated appearance. However, the longitudinal furrow (which extends from the 1st. apical plate to the antapex), is mostly not covered by spines.
The hypotheca consists of 6 postcingular plates, of one accessory plate (1p) and of one polygonal, convex antapical plate. Here agian, plate 1''' is greatly reduced, and plate 2''' likewise has not as yet reached the normal size of the remaining postequatorial plates.
The range of variations of this species is of a small order of magnitude and is limited to slight deviations from the spherical shape of the envelope anf to different lengths of the spines located on plates and sutures; however, even in the extreme case, these spines can not attian lenghts of more than 4 microns.
The membrane apperas to be have a light yellow coloration, however, due to the spine coverage, gives an overall appearance of being somewhat darker.
Relationships: This species differs from the G. aculeata in that the plates display here a dense and isoalted spine-coverage (whereas in the case of G. aculeata the plates are ornemented with vermicular, low tubercle seams); a further criterium is the fact that the granualted sutures, which are developed in a striation-like manner, are not very prominent here.