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Ctenidodinium capitatum
From Fensome et al., 2019:
Ctenidodinium capitatum Wheeler and Sarjeant, 1990, p.304,306, pl.7, figs.5–6; pl.8, figs.1–2; text-fig.9 ex Wheeler and Sarjeant,
1992, p.381. Holotype: Wheeler and Sarjeant, 1990, pl.7, figs.5–6; pl.8, fig.1; text-fig.9. This name was not validly
published in Wheeler and Sarjeant (1990), since the lodgement of the holotype was not cited (ICN Article 40.7).
Age: Middle Jurassic.
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Original description: [Wheeler and Sarjeant, 1990]:
Ctenidodinium capitatum sp. nov. (Plate 7 figs. 5-6; Plate 8 figs. 1-2; Text-figure 9)
?1970 Ctenidodinium aff. tenellum Defiandre. Gocht, “Form B" p. 142, pl. 32, Figure 18, text-figure 7.
?1979 Ctenidodinium ornatum (Eisenack) Deflandre. Ashraf, p. 130, pl. 4, figure 16.
Figured specimen: Pl. 7 figures 5-6, PI. 8 figure 1--G. Mus. Pd. 168; 138.3/10.9. P1.8 figure 2--G. Mus. Pd. 142; 129.3/08.1.
Derivation of name: L., capitatus, having a head. After the capitate form of the processes.
Diagnosis: A species of Ctenidodinium having a pronouncedly polygonal central body, essentially equidimensional, with only a slight tendency to be broader than long. Because of this shape, specimens are commonly encountered in polar view. The cyst is proximochorate, with an holotabulate autophragm.. Parasutures are marked by rows of processes joined proximally by low crests. The processes are short (1/5 cyst diameter) and solid. They appear circular in cross-section, tapering gently. Distally, they are capitate to briefly bifid, rarely acuminate. Gonal processes are longer than intergonal processes. Phragma densely granulate.
Paratabulation gonyaulacacean; formula 1pr?, 4', 1a, 6", 6c?, 6'", 1p, 1"". Archaeopyle epitractal, Type tAtP, the archaeopyle suture being immediately anterior to the cingulum. Operculum (epitract) usually dissociated from hypotract. Epitract less robust than the hypotract and tends to disintegrate more often, thus depleting the assemblage with respect to epitracts.
The cingulum displays no ventral offset. Its anterior margin (where the schism
takes place) bears no parasutural features. Conversely, the posterior margin is marked by very prominent parasutural processes and septa. In general, the parasutural features of the hypotract are more strongly developed than those of the epitract. On well-preserved specimens a sulcus is discernible on the hypotract only.
Material: Thirty-seven specimens, encountered in samples 1265, 1266 and 1267, all Dalichai Formation.
Dimensions: Holotype (P1. 7, figures 5, 6; P1. 8, figure 1; Text-figure 9) - length 76 um, breadth 76 um, intergonal processes 11 m, gonal processes 15 um. Second specimen, in antapical view (Pl. 8 figure 2) - diameter 65 um. Range: length 46 (59) 76 um, breadth 48 (69) 76 um, processes 8 (10) 15 um, (9 specimens measured).
Remarks: C. capitatum is comparable in spine number and spacing to C. tenellum Deflandre (1938, p. 182, pl. 9 figures 3-10), but differs in its larger size, thicker wall, and uniformly capitate spines. In other respects, the characteristics of C. tenellum are obscure. Regarding Deflandre's type material of that species, contained in chert flakes, the second author has noted: I have examined the holotype and consider it to be of too obscure a character to be a fit basis for a species and to be not a Ctenidodinium, as that genus is presently understood. (Sarjeant, 1978, p. 37).
Use of the name C. tenellum since its proposal by Deflandre has been limited. An epitract from the English Bathonian, illustrated and attributed to this species by Benson (1985, pl. 2 figure 3), appears to us more probably attributable to Dichadogonyaulax sellwoodiü Sarjeant, 1975. In addition, Gocht (1970) described two cyst forms which he regarded as related to C. tenellum but which differed markedly in known details. One of these, Forma B, is sufficiently similar to C. capitatum to be tentatively placed by us into its synonymy. It is conceivable that C. tenellum may be
rendered utilizable by later studies and may prove to incorporate, within its range, forms of the morphology here described. However, our present feeling is that use of the name tenellum should be limited to the type material. Ctenidodinium elegantulum Millioud (1969, p. 427, pl. 2 figures 1-2) is similar to C. capitatum, but was diagnosed as having a strongly helicoid cingulum (though this feature is not apparent in Millioud's figures) and has much larger crest spines, with only minimal basal linkage. One of the specimens figured by Ashraf (1979, pl. 4 figure 16), from the Middle to Late Jurassic of Afghanistan, appears referable to this new species rather than to C. ornatum, in which it was placed. However, for the moment, C. capitatum can be said to have been recognized with certainty only from Iran.
Ctenidodinium capitatum Wheeler and Sarjeant, 1990, p.304,306, pl.7, figs.5–6; pl.8, figs.1–2; text-fig.9 ex Wheeler and Sarjeant,
1992, p.381. Holotype: Wheeler and Sarjeant, 1990, pl.7, figs.5–6; pl.8, fig.1; text-fig.9. This name was not validly
published in Wheeler and Sarjeant (1990), since the lodgement of the holotype was not cited (ICN Article 40.7).
Age: Middle Jurassic.
---------------------------------------------------------------------------------------------------
Original description: [Wheeler and Sarjeant, 1990]:
Ctenidodinium capitatum sp. nov. (Plate 7 figs. 5-6; Plate 8 figs. 1-2; Text-figure 9)
?1970 Ctenidodinium aff. tenellum Defiandre. Gocht, “Form B" p. 142, pl. 32, Figure 18, text-figure 7.
?1979 Ctenidodinium ornatum (Eisenack) Deflandre. Ashraf, p. 130, pl. 4, figure 16.
Figured specimen: Pl. 7 figures 5-6, PI. 8 figure 1--G. Mus. Pd. 168; 138.3/10.9. P1.8 figure 2--G. Mus. Pd. 142; 129.3/08.1.
Derivation of name: L., capitatus, having a head. After the capitate form of the processes.
Diagnosis: A species of Ctenidodinium having a pronouncedly polygonal central body, essentially equidimensional, with only a slight tendency to be broader than long. Because of this shape, specimens are commonly encountered in polar view. The cyst is proximochorate, with an holotabulate autophragm.. Parasutures are marked by rows of processes joined proximally by low crests. The processes are short (1/5 cyst diameter) and solid. They appear circular in cross-section, tapering gently. Distally, they are capitate to briefly bifid, rarely acuminate. Gonal processes are longer than intergonal processes. Phragma densely granulate.
Paratabulation gonyaulacacean; formula 1pr?, 4', 1a, 6", 6c?, 6'", 1p, 1"". Archaeopyle epitractal, Type tAtP, the archaeopyle suture being immediately anterior to the cingulum. Operculum (epitract) usually dissociated from hypotract. Epitract less robust than the hypotract and tends to disintegrate more often, thus depleting the assemblage with respect to epitracts.
The cingulum displays no ventral offset. Its anterior margin (where the schism
takes place) bears no parasutural features. Conversely, the posterior margin is marked by very prominent parasutural processes and septa. In general, the parasutural features of the hypotract are more strongly developed than those of the epitract. On well-preserved specimens a sulcus is discernible on the hypotract only.
Material: Thirty-seven specimens, encountered in samples 1265, 1266 and 1267, all Dalichai Formation.
Dimensions: Holotype (P1. 7, figures 5, 6; P1. 8, figure 1; Text-figure 9) - length 76 um, breadth 76 um, intergonal processes 11 m, gonal processes 15 um. Second specimen, in antapical view (Pl. 8 figure 2) - diameter 65 um. Range: length 46 (59) 76 um, breadth 48 (69) 76 um, processes 8 (10) 15 um, (9 specimens measured).
Remarks: C. capitatum is comparable in spine number and spacing to C. tenellum Deflandre (1938, p. 182, pl. 9 figures 3-10), but differs in its larger size, thicker wall, and uniformly capitate spines. In other respects, the characteristics of C. tenellum are obscure. Regarding Deflandre's type material of that species, contained in chert flakes, the second author has noted: I have examined the holotype and consider it to be of too obscure a character to be a fit basis for a species and to be not a Ctenidodinium, as that genus is presently understood. (Sarjeant, 1978, p. 37).
Use of the name C. tenellum since its proposal by Deflandre has been limited. An epitract from the English Bathonian, illustrated and attributed to this species by Benson (1985, pl. 2 figure 3), appears to us more probably attributable to Dichadogonyaulax sellwoodiü Sarjeant, 1975. In addition, Gocht (1970) described two cyst forms which he regarded as related to C. tenellum but which differed markedly in known details. One of these, Forma B, is sufficiently similar to C. capitatum to be tentatively placed by us into its synonymy. It is conceivable that C. tenellum may be
rendered utilizable by later studies and may prove to incorporate, within its range, forms of the morphology here described. However, our present feeling is that use of the name tenellum should be limited to the type material. Ctenidodinium elegantulum Millioud (1969, p. 427, pl. 2 figures 1-2) is similar to C. capitatum, but was diagnosed as having a strongly helicoid cingulum (though this feature is not apparent in Millioud's figures) and has much larger crest spines, with only minimal basal linkage. One of the specimens figured by Ashraf (1979, pl. 4 figure 16), from the Middle to Late Jurassic of Afghanistan, appears referable to this new species rather than to C. ornatum, in which it was placed. However, for the moment, C. capitatum can be said to have been recognized with certainty only from Iran.