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Canninginopsis denticulata
Canninginopsis denticulata, Cookson and Eisenack, 1962; Marshall, 1990, provided a detailed description of this species.
Holotype: Cookson and Eisenack 1962b, Pl. 1, fig. 16.
Locus typicus: Australia
Stratum typicum: ?
Age: Albian- Cenomanian
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Original description: [Cookson and Eisenack 1962b, p. 488]:
Description:
Shell slightly longer than broad, usually flattened by compression, apical projection usually low and bluntly rounded, antapical projections short, blunt, sometimes scarcely noticeable, generally slightly different in size. Girdle shallow, marginal indentations generally clearly defined. Longitudinal furrow obliquely directed toward the right-hand side of shell, relatively broad and shallow in the hypotheca, narrower and level with the surface in the epitheca. Fields outlined by small tooth-like projections which are sometimes only faintly indicated.
Tabulation (text figure 1 a b): 4', 6", 6"', l p, 1 "". In the region of the longitudinal furrow there are (a) a large field which lies adjacent to plate l""; (b) a group of small fields; and (c) a long narrow field, the-upper limit of which reaches the line along which the apical part of the shell or "lid" becomes detached. The surface of the "lid" is marked out into four approximately equal fields (plate 1, fig. 18).
Dimensions:
Holotype: 120 µm long, 111 µm broad. Range: 90-120 µm long, 95-128 µm broad.
Age end occurrence: (?)Albian-Aptian: Rakich's bore at 350-355 ft.; Jandacot bore at 450 ft. Albian: Santos Oodnadatta bore at 307 and 327 ft. Probablv Albian: Gingin, Wapet's seismic shot holes L9 at 305 ft. and L8 at 240 ft.; Osborne formation, Attadale bore at 374 509, 529 and 539 ft.; Pearce bore No. 3 (Bullsbrook) between 154 and 200 ft.; Power House bore at 478 and 590 ft.; Mt. Lyall bore No. 5 at 886 ft.; Guildford bore at 300 ft. (?)Upper Albian to Cenomanian: Gingin, Wapet's seismic shot hole B 1 at 190, 200,210, and 220 ft.; Osborne formation, Fremantle Traffic Bridge bores No. 5 at 100 ft. and No. 2 at 114, 144, 168 ft.; Roberts Street bore between 470 and 490 ft.; Attadale bore at 164, 354, and 374 ft.; Subiaco bore at 358 and 436 ft.- King Edward Street bore between 265 and 295 ft., Hampden Road bore between 398 and 430 ft. Probably Cenomanian: Brickhouse bore (1950) at 1210 ft.
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Supplemental description:
Marshall 1990, p. 82-84:
Discussion/description:
Specimens encountered during this study agree closely with the type material (Cookson & Eisenack, 1962, p. 488, pl. I, figs 16-19, text-fig. 2a, b), and those described and illustrated by Morgan (1980, p. 17, pl. 3, figs 9-14). In addition, some faint morphological features are evident on the present specimens which have not been recorded by earlier authors.
Firstly, six equatorial paraplates are evident within the paracingulum, and secondly, the rounded to polygonal field between paraplates lu and 1i sometimes contains one or two low ridges or knobs that are occasionally set in a shallow depression. These appear to be flagellar markings. The anterior margin of paraplate 2 appears to have a variable outline ranging from planate to camerate. On specimens with camerate margins, the point of inflection is close to the lateral boundary between paraplates 2 and 3, and it is often difficult to distinguish the individual outlines, especially when an accessory suture is developed between paraplates 2 and 3 (Fig. 4A-K).
The species has a sexiform, gonyaulacoid paratabulation, and the pattern shown in Fig. 5A-E is generally consistent with that determined in most other studies of the taxon (Cookson & Eisenack, 1962; Morgan 1980; Wall & Evitt, 1975; Evitt, 1985; Bint, 1986). However, the sulcal paraplates were not numbered by the earlier authors. These are labelled on the present specimens because their arrangement is similar to that of the analogous plates on the modern genus Gonyaulax Diesing 1866 (Evitt, 1985, fig. 5.15). The relationship between paraplates fu and ai is usually uncertain because their boundaries adjoining the flagellar marking are extremely faint and incomplete. However, on one specimen (Fig. 5C-D), these paraplates are in contract between the flagellar marking and 1i as on Gonyaulax.
A different interpretation of the paratabulation on C. denticulata has been proposed by Duxbury (1983; p. 27, text-fig. 9), using the diagram of the species given in Cookson & Eisenack (1962; text-fig. 2), and this stems from his belief that the paraplates have a ceratioid arrangement. His interpretation differs from that presented here in the labeling of the paraplates on the paracingulum and hypocyst. His interpretation is rejected for two reasons. Firstly, six rather than five paraplates are evident within the paracingulum. Secondly, two paraplates, Y and Z, are evident within the area assigned to the antipolar paraplate, I"" in Kofoid notation, by Duxbury, and these are separated by a boundary extending between the antapical horns. This boundary is evident on the type material (Cookson & Eisenack, 1962 pl. 1, figs 16, 17). These two misinterpretations make Duxbury's pattern inconsistent with both ceratioid and sexiform gonyaulacoid paratabulations.
Some paraplate boundaries on C. denticulata appear to be marked by two closely spaced rows of granules rather than just a single parasutural row. These apparent double rows are most clear near paraplate triple junctions, and usually merge to form single rows over the remainder of the paraplate outlines. This feature is evident on the illustrations of the type material (Cookson & Eisenack, 1962, pl. 1, figs 16, 17), which has also been noted by Morgan (1980), where paraplate outlines are marked by either a single or double row of granules. This explains the frequent occurrence of a row granules along either side of the archeopyle suture on the pre-equatorial and polar paraplates (e.g. Fig. 6E, K).
Dimensions:
Cyst without operculum, length 66(73)80 µm; width 73(85)98 µm (14 specimens).
Distribution:
The species has been recorded from the late Albian-Cenomanian to possibly Turonian of the Perth Basin in Dandaragan boreholes D33 (51-75 m) and D31 (97-98 m). Known previously from the Albian-Cenomanian of the Perth Basin (Cookson & Eisenack, 1962, 1968; Morgan, 1980), ?early-middle Albian to Cenomanian of DSDP Site 258, on the Naturaliste Plateau (Morgan, 1980), Albian-Cenomanian of the Browse Basin (Morgan, 1980), late Albian-Cenomanian of the Bonaparte Basin (Morgan, 1980), Cenomanian of the Money Shoal Basin (Norvick & Burger, 1976), and late Albian of the Eromanga Basin (Cookson & Eisenack, 1962; Morgan, 1980). Helby et al. (1987) consider that it ranges from early-middle Albian to Cenomanian in Australia. The specimen referred to C. denticulata by Kjellstrom (1973; p. 14, fig. 6), from the early-middle Maastrichtian of Sweden, bears little resemblance to the Australian specimens.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Canninginopsis denticulata Cookson and Eisenack, 1962b, according to Cookson and Eisenack (1962), has an apical projection usually low and bluntly rounded and antapical projections short, blunt, sometime scarcely noticeable, generally of unequal development. Girdle shallow, longitudinal furrow oblique and widening posteriorly. Fields outlined by small tooth-like projections which are sometimes only faintly indicated. Size: length 90-120 µm, width 95-128 µm.
Holotype: Cookson and Eisenack 1962b, Pl. 1, fig. 16.
Locus typicus: Australia
Stratum typicum: ?
Age: Albian- Cenomanian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack 1962b, p. 488]:
Description:
Shell slightly longer than broad, usually flattened by compression, apical projection usually low and bluntly rounded, antapical projections short, blunt, sometimes scarcely noticeable, generally slightly different in size. Girdle shallow, marginal indentations generally clearly defined. Longitudinal furrow obliquely directed toward the right-hand side of shell, relatively broad and shallow in the hypotheca, narrower and level with the surface in the epitheca. Fields outlined by small tooth-like projections which are sometimes only faintly indicated.
Tabulation (text figure 1 a b): 4', 6", 6"', l p, 1 "". In the region of the longitudinal furrow there are (a) a large field which lies adjacent to plate l""; (b) a group of small fields; and (c) a long narrow field, the-upper limit of which reaches the line along which the apical part of the shell or "lid" becomes detached. The surface of the "lid" is marked out into four approximately equal fields (plate 1, fig. 18).
Dimensions:
Holotype: 120 µm long, 111 µm broad. Range: 90-120 µm long, 95-128 µm broad.
Age end occurrence: (?)Albian-Aptian: Rakich's bore at 350-355 ft.; Jandacot bore at 450 ft. Albian: Santos Oodnadatta bore at 307 and 327 ft. Probablv Albian: Gingin, Wapet's seismic shot holes L9 at 305 ft. and L8 at 240 ft.; Osborne formation, Attadale bore at 374 509, 529 and 539 ft.; Pearce bore No. 3 (Bullsbrook) between 154 and 200 ft.; Power House bore at 478 and 590 ft.; Mt. Lyall bore No. 5 at 886 ft.; Guildford bore at 300 ft. (?)Upper Albian to Cenomanian: Gingin, Wapet's seismic shot hole B 1 at 190, 200,210, and 220 ft.; Osborne formation, Fremantle Traffic Bridge bores No. 5 at 100 ft. and No. 2 at 114, 144, 168 ft.; Roberts Street bore between 470 and 490 ft.; Attadale bore at 164, 354, and 374 ft.; Subiaco bore at 358 and 436 ft.- King Edward Street bore between 265 and 295 ft., Hampden Road bore between 398 and 430 ft. Probably Cenomanian: Brickhouse bore (1950) at 1210 ft.
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Supplemental description:
Marshall 1990, p. 82-84:
Discussion/description:
Specimens encountered during this study agree closely with the type material (Cookson & Eisenack, 1962, p. 488, pl. I, figs 16-19, text-fig. 2a, b), and those described and illustrated by Morgan (1980, p. 17, pl. 3, figs 9-14). In addition, some faint morphological features are evident on the present specimens which have not been recorded by earlier authors.
Firstly, six equatorial paraplates are evident within the paracingulum, and secondly, the rounded to polygonal field between paraplates lu and 1i sometimes contains one or two low ridges or knobs that are occasionally set in a shallow depression. These appear to be flagellar markings. The anterior margin of paraplate 2 appears to have a variable outline ranging from planate to camerate. On specimens with camerate margins, the point of inflection is close to the lateral boundary between paraplates 2 and 3, and it is often difficult to distinguish the individual outlines, especially when an accessory suture is developed between paraplates 2 and 3 (Fig. 4A-K).
The species has a sexiform, gonyaulacoid paratabulation, and the pattern shown in Fig. 5A-E is generally consistent with that determined in most other studies of the taxon (Cookson & Eisenack, 1962; Morgan 1980; Wall & Evitt, 1975; Evitt, 1985; Bint, 1986). However, the sulcal paraplates were not numbered by the earlier authors. These are labelled on the present specimens because their arrangement is similar to that of the analogous plates on the modern genus Gonyaulax Diesing 1866 (Evitt, 1985, fig. 5.15). The relationship between paraplates fu and ai is usually uncertain because their boundaries adjoining the flagellar marking are extremely faint and incomplete. However, on one specimen (Fig. 5C-D), these paraplates are in contract between the flagellar marking and 1i as on Gonyaulax.
A different interpretation of the paratabulation on C. denticulata has been proposed by Duxbury (1983; p. 27, text-fig. 9), using the diagram of the species given in Cookson & Eisenack (1962; text-fig. 2), and this stems from his belief that the paraplates have a ceratioid arrangement. His interpretation differs from that presented here in the labeling of the paraplates on the paracingulum and hypocyst. His interpretation is rejected for two reasons. Firstly, six rather than five paraplates are evident within the paracingulum. Secondly, two paraplates, Y and Z, are evident within the area assigned to the antipolar paraplate, I"" in Kofoid notation, by Duxbury, and these are separated by a boundary extending between the antapical horns. This boundary is evident on the type material (Cookson & Eisenack, 1962 pl. 1, figs 16, 17). These two misinterpretations make Duxbury's pattern inconsistent with both ceratioid and sexiform gonyaulacoid paratabulations.
Some paraplate boundaries on C. denticulata appear to be marked by two closely spaced rows of granules rather than just a single parasutural row. These apparent double rows are most clear near paraplate triple junctions, and usually merge to form single rows over the remainder of the paraplate outlines. This feature is evident on the illustrations of the type material (Cookson & Eisenack, 1962, pl. 1, figs 16, 17), which has also been noted by Morgan (1980), where paraplate outlines are marked by either a single or double row of granules. This explains the frequent occurrence of a row granules along either side of the archeopyle suture on the pre-equatorial and polar paraplates (e.g. Fig. 6E, K).
Dimensions:
Cyst without operculum, length 66(73)80 µm; width 73(85)98 µm (14 specimens).
Distribution:
The species has been recorded from the late Albian-Cenomanian to possibly Turonian of the Perth Basin in Dandaragan boreholes D33 (51-75 m) and D31 (97-98 m). Known previously from the Albian-Cenomanian of the Perth Basin (Cookson & Eisenack, 1962, 1968; Morgan, 1980), ?early-middle Albian to Cenomanian of DSDP Site 258, on the Naturaliste Plateau (Morgan, 1980), Albian-Cenomanian of the Browse Basin (Morgan, 1980), late Albian-Cenomanian of the Bonaparte Basin (Morgan, 1980), Cenomanian of the Money Shoal Basin (Norvick & Burger, 1976), and late Albian of the Eromanga Basin (Cookson & Eisenack, 1962; Morgan, 1980). Helby et al. (1987) consider that it ranges from early-middle Albian to Cenomanian in Australia. The specimen referred to C. denticulata by Kjellstrom (1973; p. 14, fig. 6), from the early-middle Maastrichtian of Sweden, bears little resemblance to the Australian specimens.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Canninginopsis denticulata Cookson and Eisenack, 1962b, according to Cookson and Eisenack (1962), has an apical projection usually low and bluntly rounded and antapical projections short, blunt, sometime scarcely noticeable, generally of unequal development. Girdle shallow, longitudinal furrow oblique and widening posteriorly. Fields outlined by small tooth-like projections which are sometimes only faintly indicated. Size: length 90-120 µm, width 95-128 µm.