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Canningia reticulata
Canningia reticulata, Cookson and Eisenack, 1960; emend. Below, 1981; emend. Helby, 1987
Holotype: Cookson and Eisenack, 1960, pl.38, fig.1; Helby, 1987, fig.27J
Locus typicus: Jarlemai Siltstone, West Australia
Stratum typicum: Tithonian
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Original description: [Cookson and Eisenack, 1960, p. 251]:
Description:
Shell with straight or rounded sides; apical projection not prominent, basal indention clearly marked; a girdle is usually present slightly above the equator. Shell-membrane densely and irregular reticulate, the reticulum low, small-meshed and thick-walled.
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Emendations:
Below, 1981, p. 32:
Diagnosis:
Two-layered cyst. The smooth endophragma forms the sphaeroidal, lenticular inner body. Periphragm smooth, forming the in outline sphaeriodal to pentagonal outer body. ?Endophragmal, spongious, matted lattice structure fills pericoel.
Paratabulation weakly indicated, seemingly gonyaulaciodal.
Paracingulum spiral, indented into outer body, parasulcus just as thick, undifferentiated dent recognisable.
Archaeopyle apical, Type "Aa", operculum enlarged.
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Helby, 1987, p. 322:
Description:
Cyst lenticular with obtuse, low apical horn, 2 low rounded antapical horns, with that on the left larger and much further from the paracingulum. Ectophragm usually protrusive at the paracingulum. Autophragm and ectophragm relatively close to each other, and ectocoel wider below horns and paracingulum than elsewhere.
Supporting structures within the ectocoel varying in length and distribution and longest and most closely packed in parasutural areas (up to 6 µm long). Ectophragm finely reticulate to rugoreticulate, although some specimens may have granulate or smooth areas.
Paratabulation indicated by principal and accessory archeopyle sutures. However, on some specimens paraplate boundaries marked by low external ridges underlain by longer ectophragm supports. Paratabulation formula 4', 6'', 6c, 6''' ,1 p, 1'''' (Fig.28).
Archeopyle apical, type [tA], principal archeopyle suture zigzag with offset parasulcal notch and operculum free.
Parasulcus often marked by a reduction in the extent, or even absence, of ectocoel development and characteristically sinuous.
Paracingulum indicated laterally by equatorial protrusion of wall layers and transversely by slight parasutural ridges. Paracingulum markedly offset adjacent to the parasulcus (Fig.28).
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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.
Canningia reticulata Cookson and Eisenack, 1960b, emend. Below, 1981a, emend. Helby, 1987, is holocavate but over most of the surface the ectophragm is closely appressed to the autophragm. Ectocoel wider below horns and paracingulum than elsewhere. Supporting structures with ectocoel of varying length, up to 6 µm. Ectophragm finely reticulate to rugoreticulate. Paratabulation indicated by principal and accessory archeopyle sutures. Below (1981) said that the operculum was attached. He thought this significant and included similar forms with free opercula in Cyclonephelium. Helby (1987) in his emendation states that the operculum is free. Size according to Helby (1987), overall length 100-115 µm, overall width 70-97 µm.
Holotype: Cookson and Eisenack, 1960, pl.38, fig.1; Helby, 1987, fig.27J
Locus typicus: Jarlemai Siltstone, West Australia
Stratum typicum: Tithonian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Eisenack, 1960, p. 251]:
Description:
Shell with straight or rounded sides; apical projection not prominent, basal indention clearly marked; a girdle is usually present slightly above the equator. Shell-membrane densely and irregular reticulate, the reticulum low, small-meshed and thick-walled.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emendations:
Below, 1981, p. 32:
Diagnosis:
Two-layered cyst. The smooth endophragma forms the sphaeroidal, lenticular inner body. Periphragm smooth, forming the in outline sphaeriodal to pentagonal outer body. ?Endophragmal, spongious, matted lattice structure fills pericoel.
Paratabulation weakly indicated, seemingly gonyaulaciodal.
Paracingulum spiral, indented into outer body, parasulcus just as thick, undifferentiated dent recognisable.
Archaeopyle apical, Type "Aa", operculum enlarged.
-----------------------------------------------------
Helby, 1987, p. 322:
Description:
Cyst lenticular with obtuse, low apical horn, 2 low rounded antapical horns, with that on the left larger and much further from the paracingulum. Ectophragm usually protrusive at the paracingulum. Autophragm and ectophragm relatively close to each other, and ectocoel wider below horns and paracingulum than elsewhere.
Supporting structures within the ectocoel varying in length and distribution and longest and most closely packed in parasutural areas (up to 6 µm long). Ectophragm finely reticulate to rugoreticulate, although some specimens may have granulate or smooth areas.
Paratabulation indicated by principal and accessory archeopyle sutures. However, on some specimens paraplate boundaries marked by low external ridges underlain by longer ectophragm supports. Paratabulation formula 4', 6'', 6c, 6''' ,1 p, 1'''' (Fig.28).
Archeopyle apical, type [tA], principal archeopyle suture zigzag with offset parasulcal notch and operculum free.
Parasulcus often marked by a reduction in the extent, or even absence, of ectocoel development and characteristically sinuous.
Paracingulum indicated laterally by equatorial protrusion of wall layers and transversely by slight parasutural ridges. Paracingulum markedly offset adjacent to the parasulcus (Fig.28).
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Canningia reticulata Cookson and Eisenack, 1960b, emend. Below, 1981a, emend. Helby, 1987, is holocavate but over most of the surface the ectophragm is closely appressed to the autophragm. Ectocoel wider below horns and paracingulum than elsewhere. Supporting structures with ectocoel of varying length, up to 6 µm. Ectophragm finely reticulate to rugoreticulate. Paratabulation indicated by principal and accessory archeopyle sutures. Below (1981) said that the operculum was attached. He thought this significant and included similar forms with free opercula in Cyclonephelium. Helby (1987) in his emendation states that the operculum is free. Size according to Helby (1987), overall length 100-115 µm, overall width 70-97 µm.