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Canningia pistica
Canningia pistica, Helby, 1987
Holotype: Helby, 1987, fig.30I-L
Locus typicus: Australia
Stratum typicum: Hauterivian
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Original description: [Helby, 1987, p. 326-327]:
Description:
Cysts lenticular with a low, obtuse apical horn, and 2 small antapical horns, of which the left horn is usually larger and more distant from the paracingulum. Distinct lateral protrusions evident at paracingulum (Fig.29E).
Wall layers separated by ectophragm supports up to 10 µm in length, 0.5-2 µm at base, often expanding distally to 3 µm at their junctions with ectophragm reticulum. Distribution of the supports variable, generally concentrated in the vicinity of parasutural boundaries, but also as intratabular clusters (Fig.30L). Autophragm smooth to scabrate between ectophragm supports, about 1 µm thick. Ectophragm thin, finely reticulate (Fig.30L) often incomplete in the parasulcal area.
Paratabulation usually indicated on the epicyst by the principal and accessory archeopyle sutures and by faint parasutural alignment of more substantial ectophragm supports. Parasutural lineation of supports most clearly expressed on the hypocyst, particularly along the paracingulum. Complete paratabulation formula not determined.
Archeopyle apical, type [tA], principal suture zigzag with offset parasulcal notch; operculum free.
Paracingulum indicated by transverse subequatorial protrusion of both wall layers, by the greater length and concentration of the larger and wider ectophragm supports and by obvious offsetting of the ends of the paracingulum.
Dimensions:
See Fig. 24 for key to measurements.
Seventeen specimens from Plover-2 well at 607.5m, in the M. testudinaria Zone were measured as:
A, 85(94)115 µm; C, 67(86)100 µm; E, 100(100)135 µm; F, 87-115 µm.
Thirty specimens from Plover-2 well at 612.6m, in the M. testudinaria Zone were measured as:
A, 77(114)160 µm; B, 70(102)140 µm; C, 74(102)137 µm; D, 87(93)115 µm; E, 145-152 µm (2 specimens).
Affinities:
Canningia grandis is generally larger than C. pistica, lacks distinct parasutural alignment of ectophragm supports and has a much more robust ectophragm reticulum. Canningia reticulata has smaller, more densely packed ectophragm supports and a more closely appressed, very finely reticulate to rugoreticulate ectophragm. Circulodinium attadalicum (Cookson & Eisenack) and C. hirtella Alberti 1961 may superficially resemble C. pistica but lack an ectophragm.
Holotype: Helby, 1987, fig.30I-L
Locus typicus: Australia
Stratum typicum: Hauterivian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Helby, 1987, p. 326-327]:
Description:
Cysts lenticular with a low, obtuse apical horn, and 2 small antapical horns, of which the left horn is usually larger and more distant from the paracingulum. Distinct lateral protrusions evident at paracingulum (Fig.29E).
Wall layers separated by ectophragm supports up to 10 µm in length, 0.5-2 µm at base, often expanding distally to 3 µm at their junctions with ectophragm reticulum. Distribution of the supports variable, generally concentrated in the vicinity of parasutural boundaries, but also as intratabular clusters (Fig.30L). Autophragm smooth to scabrate between ectophragm supports, about 1 µm thick. Ectophragm thin, finely reticulate (Fig.30L) often incomplete in the parasulcal area.
Paratabulation usually indicated on the epicyst by the principal and accessory archeopyle sutures and by faint parasutural alignment of more substantial ectophragm supports. Parasutural lineation of supports most clearly expressed on the hypocyst, particularly along the paracingulum. Complete paratabulation formula not determined.
Archeopyle apical, type [tA], principal suture zigzag with offset parasulcal notch; operculum free.
Paracingulum indicated by transverse subequatorial protrusion of both wall layers, by the greater length and concentration of the larger and wider ectophragm supports and by obvious offsetting of the ends of the paracingulum.
Dimensions:
See Fig. 24 for key to measurements.
Seventeen specimens from Plover-2 well at 607.5m, in the M. testudinaria Zone were measured as:
A, 85(94)115 µm; C, 67(86)100 µm; E, 100(100)135 µm; F, 87-115 µm.
Thirty specimens from Plover-2 well at 612.6m, in the M. testudinaria Zone were measured as:
A, 77(114)160 µm; B, 70(102)140 µm; C, 74(102)137 µm; D, 87(93)115 µm; E, 145-152 µm (2 specimens).
Affinities:
Canningia grandis is generally larger than C. pistica, lacks distinct parasutural alignment of ectophragm supports and has a much more robust ectophragm reticulum. Canningia reticulata has smaller, more densely packed ectophragm supports and a more closely appressed, very finely reticulate to rugoreticulate ectophragm. Circulodinium attadalicum (Cookson & Eisenack) and C. hirtella Alberti 1961 may superficially resemble C. pistica but lack an ectophragm.