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Canningia palliata
Canningia palliata, Brideaux, 1977
Tax. jr. synonym of Canningia reticulata Cookson and Eisenack, 1960, according to Helby, 1987.
Holotype: Brideaux, 1977, pl.3, figs.1-4
Locus typicus: Richardson Mountains, District of Mackenzie, Canada
Stratum typicum: Barremian
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Original description: [Brideaux, 1977, p. 11-12]:
Diagnosis:
Shape: Pericyst ambitus ovoid to ovoid-pentagonal; the apex produced into a short, rounded apical prominence; the antapex rounded or with development of one or two antapical prominences, of the two, the left one larger; maximum width occurring at the latitude of the pericingulum. Endocyst closely appressed to the pericyst except at the antapex where expression of antapical endocyst prominences may be less strongly developed, forming one or two antapical pericoels; dorso-ventral compression.
Phragma: Periphragm discontinuous, consisting of a reticulate to imperfect rugulo-reticulate meshwork; the muri low, 0.5 µm high and 1-2 µm wide, and bearing baculate, bifid or simple projections, 1-3 µm high; the lumina irregularly shaped, up to 5 µm in maximum diameter. Endophragm scabrate, 1.5-2.0 µm thick.
Paratabulation: Operculum, archeopyle outline and development of accessory parasutures in the precingular paraplate series denotes a paratabulation of 4", 6", c, x""", ?p on both pericyst and endocyst. Formula A.
Archeopyle/operculum: Archeopyle formed by the loss of the four apical paraplates. Operculum simple and free occasionally remaining partly attached ventrally, the two layers separating as a unit.
Pericingulum/perisulcus: Pericingulum indistinctly represented by reduction of periphragm on some specimens, but generally not represented- perisulcal position indicated by reduction or absence of periphragm; perisulcus offset and inclined left to right, terminating at the antapex.
Dimensions:
Overall length (2 complete specimens), 74-77 µm; overall width, 65-95 µm; length of incomplete specimens, 62-83 µm.
Affinities:
Canningia palliata differs from Canningia reticulata Cookson and Eisenack, 1960 in that the periphragm does not show evidence of paratabulation; it differs from Cyclonephelium vannophorum Davey 1969 in that the periphragm is reduced only in the parasulcal region, and the processes arising from the reticulate periphragm are baculate to bifid rather than fan-shaped and complex.
Tax. jr. synonym of Canningia reticulata Cookson and Eisenack, 1960, according to Helby, 1987.
Holotype: Brideaux, 1977, pl.3, figs.1-4
Locus typicus: Richardson Mountains, District of Mackenzie, Canada
Stratum typicum: Barremian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Brideaux, 1977, p. 11-12]:
Diagnosis:
Shape: Pericyst ambitus ovoid to ovoid-pentagonal; the apex produced into a short, rounded apical prominence; the antapex rounded or with development of one or two antapical prominences, of the two, the left one larger; maximum width occurring at the latitude of the pericingulum. Endocyst closely appressed to the pericyst except at the antapex where expression of antapical endocyst prominences may be less strongly developed, forming one or two antapical pericoels; dorso-ventral compression.
Phragma: Periphragm discontinuous, consisting of a reticulate to imperfect rugulo-reticulate meshwork; the muri low, 0.5 µm high and 1-2 µm wide, and bearing baculate, bifid or simple projections, 1-3 µm high; the lumina irregularly shaped, up to 5 µm in maximum diameter. Endophragm scabrate, 1.5-2.0 µm thick.
Paratabulation: Operculum, archeopyle outline and development of accessory parasutures in the precingular paraplate series denotes a paratabulation of 4", 6", c, x""", ?p on both pericyst and endocyst. Formula A.
Archeopyle/operculum: Archeopyle formed by the loss of the four apical paraplates. Operculum simple and free occasionally remaining partly attached ventrally, the two layers separating as a unit.
Pericingulum/perisulcus: Pericingulum indistinctly represented by reduction of periphragm on some specimens, but generally not represented- perisulcal position indicated by reduction or absence of periphragm; perisulcus offset and inclined left to right, terminating at the antapex.
Dimensions:
Overall length (2 complete specimens), 74-77 µm; overall width, 65-95 µm; length of incomplete specimens, 62-83 µm.
Affinities:
Canningia palliata differs from Canningia reticulata Cookson and Eisenack, 1960 in that the periphragm does not show evidence of paratabulation; it differs from Cyclonephelium vannophorum Davey 1969 in that the periphragm is reduced only in the parasulcal region, and the processes arising from the reticulate periphragm are baculate to bifid rather than fan-shaped and complex.