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Cribroperidinium wetzelii
From Fensome et al., 2019:
Cribroperidinium wetzelii (Lejeune-Carpentier, 1939, p.B526; text-figs.1–2) Helenes, 1984, p.124. Emendations: Lejeune-Carpentier,
1946, p.B189–B190, as Gonyaulax wetzelii; Lejeune-Carpentier and Sarjeant, 1981, p.2–3, as Gonyaulacysta
wetzelii. Holotype: Lejeune-Carpentier, 1939, text-figs.1–2; Lejeune-Carpentier and Sarjeant, 1981, pl.5, figs.5–6.
Originally Gonyaulax (Appendix B), subsequently Gonyaulacysta, thirdly Gonyaulacysta?, fourthly (and now)
Cribroperidinium, fifthly Millioudodinium. Lentin and Williams (1989, p.84) retained this species in
Cribroperidinium. Age: Senonian.
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Original description: [Lejeune-Carpentier, 1939] (translated from French):
Gonyaulax Wetzeli n. sp. (fig. 1-2).
Polyhedral, barely taller than wide, the sides of the epitheca being flat or slightly concave, those of the hypotheca more or less rounded. There appears to be no apical horn. At the other end of the theca, small projections appear similar at first glance to the antapical spines of some extant Gonyaulax. They are due to the fact that the sutures, most of which are very raised, rise even more at the points where they meet. Other points of intersection of the sutures are similarly prominent.
Deeply hollowed girdle, with very prominent lips and appearing to have supporting ribs. Viewed from the dorsal side of the theca, the girdle appears roughly equatorial. On the ventral side, it is strongly helical and levorotatory, with its ends offset by more than twice its width. This can be estimated at an average of 5 µ, a dimension that is typical for extant species.
Ventral area very slightly curved, reaching the epitheca at a height equal to about one and a half times the average width of the girdle and descending into the hypotheca where it forms a notch in the antapical plate. At its anterior end, the area is about as wide as the girdle; it is twice as wide at the posterior end.
Tabulation: We are unable to describe the apical region. Two plates are clearly visible on the ventral surface: 1' and its unnumbered neighbor (on the left in the drawing). We assume there are four plates at the apex, but cannot specify whether these plates have an intercalary. The rest of the tabulation is consistent with what is shown in extant Gonyaulax: 6''; 6; 6"'; 1p; 1" ". 1' particularly wide; to its left, our figure 1 shows a large triangular apical at the lower angle of which a ventral pore could be found. 6" quadrangular. The portion missing from the epitheca would correspond to the third preequatorial, 3" (the one which is also often missing from Jurassic samples).
1"' narrow, extending little into the ventral area; 6"' relatively small (compared to its dimensions in most other species); 1p pentagonal, with a concave edge on the longitudinal groove side; 1"" quite narrow and heavily indented by the ventral area.
The plates of the ventral area have been delineated only with difficulty.
The anterior plate, trapezoidal in shape, is heavily indented by the flagellar pore area; there follow four intermediate plates, wider on the left side (in the figure) than on the right side; the posterior plate is kidney-shaped.
Theca ornamentation: a punctuated surface between the very loose and irregular meshes, drawn by certain lines that raise it. Here and there, but especially on the plates on the dorsal side, small spines are visible. (These details will need to be reviewed when more specimens are available).
Dimensions: total height ........................... 73 μ
width ...................................... 71 μ
Provenance: Glacial flint pebble from Eutin (Germany).
Holotype: O. Wetzel Collection (Eutin) n° 495.
Our species can be compared first to the already known Gonyaulax that are chronologically closest to it, i.e., the species from the Jurassic marls. These include more or less polyhedral forms, including one, G. eisenacki Defl., which, despite a distinctly different general appearance, shares some similarities with ours. The girdle is also highly helical, the ventral area exhibits the same development, and the plates surrounding it have roughly the same relative dimensions. However, the apicals on the ventral side are as narrow in the Jurassic microfossil as they are wide in G. Wetzeli. The latter also lacks the denticulate fringes that adorn G. eisenacki.
Among the recent forms currently known, most of which already appear in Kofoid's masterful monograph (1911), we find that the older species, G. polyedra Stein, is quite similar to G. Wetzeli. Both show angular contours, the same offset of the ends of the girdle, and some plates of the same shape. The fossil's outline is distinguished by a slightly more considerable elevation of the epitheca, or rather of the preequatorial region (with the exception of 6", which is, on the contrary, more reduced). Its hypotheca is also not very truncated, so that, ventrally, 1"" is visible under the posterior plate of the longitudinal groove.
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Emended description: [Lejeune-Carpentier, 1946] (translated from French):
Gonyaulax Weizeli Lejeune-Carpentier (fig. 1).
Based on the information provided by the new specimen shown here, the original diagnosis of the species should be amended as follows:
The apical horn, supposedly absent, is perfectly present and is even quite developed.
Four plates exist at the apex, all of which appear apical. The first, 1', is narrower than the holotopsis and can be seen to extend to the apex of the horn.
The 4' plate is also narrower, very similar in shape to 1'. Note that the 3" plate is missing from this specimen, as it was from the type specimen.
Dimensions of the specimen shown:
Height (without the horn) = 73 u;
Total height = 86 u;
Width, including the edges of the transverse groove = 73 u.
Provenance: Flint pebble collected near Eutin (northern Germany).
O. Wetzel Collection (Eutin), n° 335.
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Emended description: [Lejeune-Carpentier and Sarjeant, 1981]:
Emended diagnosis
Cyst rounded-polyhedral ; length slightly greater than breadth. The flanks of the epitract, as seen in ambital view, are flat to slightly concave; those of the hypotract are convex. Apex surmounted by a strong apical horn of moderate length. Boundaries of paraplates, cingulum and sulcus are marked by raised crests of moderate height and simple, unornamented structure. Tabulation 4', 0a, 6", 6c, 6"', 1p, 1pv, 1'"', 6s. Phragma finely and irregularly punctate, the punctations sometimes forming irregular lines. Cingulum deeply hollowed and markedly laevorotatory ; sulcus short, broad. and divided into small paraplates, exhibiting clear flagellar marks. Paraplate 3" is lost in archaeopyle formation.
Remarks
The diagnosis is emended to clarify the cingular paratabulation and to indicate the nature of the archaeopyle. The apical horn of the holotype is present but distorted (see Pl. 5 : 5-6), causing problems in its interpretation. The new observations are thus based essentially on the paratype, which is better preserved and presented. However, the same features (and, in particular, the same type of archaeopyle) are developed on both.
It should be noted that the absence of paraplate 3" was recognised from the outset (see Lejeune-Carpentier, 1946, p. B189) but the significance of this observation was not originally appreciated.
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Transfer to Cribroperidinium wetzelii: [Helenes, 1984]:
Cribroperidinium wetzelii
(Lejeune-Carpentier 1938) comb. nov.
Gonyaulax wetzeli Lejeune-Carpentier, 1938, p. 526-529, text-fig. 1, 2, (Senonian; West Germany) [basionym].
Gonyaulacysta wetzeli (Lejeune-Carpentier) Sarjeant in Davey et al., 1969, p. 10.
Cribroperidinium wetzelii (Lejeune-Carpentier, 1939, p.B526; text-figs.1–2) Helenes, 1984, p.124. Emendations: Lejeune-Carpentier,
1946, p.B189–B190, as Gonyaulax wetzelii; Lejeune-Carpentier and Sarjeant, 1981, p.2–3, as Gonyaulacysta
wetzelii. Holotype: Lejeune-Carpentier, 1939, text-figs.1–2; Lejeune-Carpentier and Sarjeant, 1981, pl.5, figs.5–6.
Originally Gonyaulax (Appendix B), subsequently Gonyaulacysta, thirdly Gonyaulacysta?, fourthly (and now)
Cribroperidinium, fifthly Millioudodinium. Lentin and Williams (1989, p.84) retained this species in
Cribroperidinium. Age: Senonian.
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Original description: [Lejeune-Carpentier, 1939] (translated from French):
Gonyaulax Wetzeli n. sp. (fig. 1-2).
Polyhedral, barely taller than wide, the sides of the epitheca being flat or slightly concave, those of the hypotheca more or less rounded. There appears to be no apical horn. At the other end of the theca, small projections appear similar at first glance to the antapical spines of some extant Gonyaulax. They are due to the fact that the sutures, most of which are very raised, rise even more at the points where they meet. Other points of intersection of the sutures are similarly prominent.
Deeply hollowed girdle, with very prominent lips and appearing to have supporting ribs. Viewed from the dorsal side of the theca, the girdle appears roughly equatorial. On the ventral side, it is strongly helical and levorotatory, with its ends offset by more than twice its width. This can be estimated at an average of 5 µ, a dimension that is typical for extant species.
Ventral area very slightly curved, reaching the epitheca at a height equal to about one and a half times the average width of the girdle and descending into the hypotheca where it forms a notch in the antapical plate. At its anterior end, the area is about as wide as the girdle; it is twice as wide at the posterior end.
Tabulation: We are unable to describe the apical region. Two plates are clearly visible on the ventral surface: 1' and its unnumbered neighbor (on the left in the drawing). We assume there are four plates at the apex, but cannot specify whether these plates have an intercalary. The rest of the tabulation is consistent with what is shown in extant Gonyaulax: 6''; 6; 6"'; 1p; 1" ". 1' particularly wide; to its left, our figure 1 shows a large triangular apical at the lower angle of which a ventral pore could be found. 6" quadrangular. The portion missing from the epitheca would correspond to the third preequatorial, 3" (the one which is also often missing from Jurassic samples).
1"' narrow, extending little into the ventral area; 6"' relatively small (compared to its dimensions in most other species); 1p pentagonal, with a concave edge on the longitudinal groove side; 1"" quite narrow and heavily indented by the ventral area.
The plates of the ventral area have been delineated only with difficulty.
The anterior plate, trapezoidal in shape, is heavily indented by the flagellar pore area; there follow four intermediate plates, wider on the left side (in the figure) than on the right side; the posterior plate is kidney-shaped.
Theca ornamentation: a punctuated surface between the very loose and irregular meshes, drawn by certain lines that raise it. Here and there, but especially on the plates on the dorsal side, small spines are visible. (These details will need to be reviewed when more specimens are available).
Dimensions: total height ........................... 73 μ
width ...................................... 71 μ
Provenance: Glacial flint pebble from Eutin (Germany).
Holotype: O. Wetzel Collection (Eutin) n° 495.
Our species can be compared first to the already known Gonyaulax that are chronologically closest to it, i.e., the species from the Jurassic marls. These include more or less polyhedral forms, including one, G. eisenacki Defl., which, despite a distinctly different general appearance, shares some similarities with ours. The girdle is also highly helical, the ventral area exhibits the same development, and the plates surrounding it have roughly the same relative dimensions. However, the apicals on the ventral side are as narrow in the Jurassic microfossil as they are wide in G. Wetzeli. The latter also lacks the denticulate fringes that adorn G. eisenacki.
Among the recent forms currently known, most of which already appear in Kofoid's masterful monograph (1911), we find that the older species, G. polyedra Stein, is quite similar to G. Wetzeli. Both show angular contours, the same offset of the ends of the girdle, and some plates of the same shape. The fossil's outline is distinguished by a slightly more considerable elevation of the epitheca, or rather of the preequatorial region (with the exception of 6", which is, on the contrary, more reduced). Its hypotheca is also not very truncated, so that, ventrally, 1"" is visible under the posterior plate of the longitudinal groove.
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Emended description: [Lejeune-Carpentier, 1946] (translated from French):
Gonyaulax Weizeli Lejeune-Carpentier (fig. 1).
Based on the information provided by the new specimen shown here, the original diagnosis of the species should be amended as follows:
The apical horn, supposedly absent, is perfectly present and is even quite developed.
Four plates exist at the apex, all of which appear apical. The first, 1', is narrower than the holotopsis and can be seen to extend to the apex of the horn.
The 4' plate is also narrower, very similar in shape to 1'. Note that the 3" plate is missing from this specimen, as it was from the type specimen.
Dimensions of the specimen shown:
Height (without the horn) = 73 u;
Total height = 86 u;
Width, including the edges of the transverse groove = 73 u.
Provenance: Flint pebble collected near Eutin (northern Germany).
O. Wetzel Collection (Eutin), n° 335.
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Emended description: [Lejeune-Carpentier and Sarjeant, 1981]:
Emended diagnosis
Cyst rounded-polyhedral ; length slightly greater than breadth. The flanks of the epitract, as seen in ambital view, are flat to slightly concave; those of the hypotract are convex. Apex surmounted by a strong apical horn of moderate length. Boundaries of paraplates, cingulum and sulcus are marked by raised crests of moderate height and simple, unornamented structure. Tabulation 4', 0a, 6", 6c, 6"', 1p, 1pv, 1'"', 6s. Phragma finely and irregularly punctate, the punctations sometimes forming irregular lines. Cingulum deeply hollowed and markedly laevorotatory ; sulcus short, broad. and divided into small paraplates, exhibiting clear flagellar marks. Paraplate 3" is lost in archaeopyle formation.
Remarks
The diagnosis is emended to clarify the cingular paratabulation and to indicate the nature of the archaeopyle. The apical horn of the holotype is present but distorted (see Pl. 5 : 5-6), causing problems in its interpretation. The new observations are thus based essentially on the paratype, which is better preserved and presented. However, the same features (and, in particular, the same type of archaeopyle) are developed on both.
It should be noted that the absence of paraplate 3" was recognised from the outset (see Lejeune-Carpentier, 1946, p. B189) but the significance of this observation was not originally appreciated.
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Transfer to Cribroperidinium wetzelii: [Helenes, 1984]:
Cribroperidinium wetzelii
(Lejeune-Carpentier 1938) comb. nov.
Gonyaulax wetzeli Lejeune-Carpentier, 1938, p. 526-529, text-fig. 1, 2, (Senonian; West Germany) [basionym].
Gonyaulacysta wetzeli (Lejeune-Carpentier) Sarjeant in Davey et al., 1969, p. 10.