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Canningia minor
Canningia minor, Cookson and Hughes, 1964
Now Kallosphaeridium? helbyi. Originally Canningia minor, subsequently Canningia? minor, thirdly Batiacasphaera minor, fourthly Chytroeisphaeridia minor, fifthly (and now) Kallosphaeridium? helbyi; see also Kallosphaeridium? minus (combination illegitimate).
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Canningia.
Holotype: Cookson and Hughes, 1964, pl.8, fig.1
Locus typicus: Barrington, Cambridgeshire, England
Stratum typicum: Late Albian-Early Cenomanian
Age: Albian-Early Cenomanian
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Original description: [Cookson and Hughes, 1964, p.43]:
Diagnosis:
Shell almost circular in outline, in well-preserved examples slightly longer than broad, opening by the removal of an apical segment along a zigzag line, the freed edge of the shell showing notches at intervals; apex with or without a short prominence, antapex usually unindented. Girdle absent; wall c. 1 µm thick, surface scabrate.
Dimensions:
Holotype 70 x 73 µm. Range 42-73 µm long, 36-73 µm broad.
Affinities: (p. 44):
Of the three described species of Canngia C. minor most closely resembles the Australian Aptian species C. colliveri Cookson and Eisenack 1960. However, it can be distinguished from this species by the less frequent occurrence of an apical prominence and indented antapex, its consistently smaller size (average dimensions of 19 specimens 56 x 52 µm), and the finer ornamentation of the shell-membrane.
In the majority of specimens the apex is partially detached and crumpled so that a more accurate ratio of length to breadth has not been possible. Plate 8, fig. 4 shows a specimen with a girdle developed; in spite of several similarities to C. minor we prefer to record this as Canngia? sp.
Now Kallosphaeridium? helbyi. Originally Canningia minor, subsequently Canningia? minor, thirdly Batiacasphaera minor, fourthly Chytroeisphaeridia minor, fifthly (and now) Kallosphaeridium? helbyi; see also Kallosphaeridium? minus (combination illegitimate).
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Canningia.
Holotype: Cookson and Hughes, 1964, pl.8, fig.1
Locus typicus: Barrington, Cambridgeshire, England
Stratum typicum: Late Albian-Early Cenomanian
Age: Albian-Early Cenomanian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Cookson and Hughes, 1964, p.43]:
Diagnosis:
Shell almost circular in outline, in well-preserved examples slightly longer than broad, opening by the removal of an apical segment along a zigzag line, the freed edge of the shell showing notches at intervals; apex with or without a short prominence, antapex usually unindented. Girdle absent; wall c. 1 µm thick, surface scabrate.
Dimensions:
Holotype 70 x 73 µm. Range 42-73 µm long, 36-73 µm broad.
Affinities: (p. 44):
Of the three described species of Canngia C. minor most closely resembles the Australian Aptian species C. colliveri Cookson and Eisenack 1960. However, it can be distinguished from this species by the less frequent occurrence of an apical prominence and indented antapex, its consistently smaller size (average dimensions of 19 specimens 56 x 52 µm), and the finer ornamentation of the shell-membrane.
In the majority of specimens the apex is partially detached and crumpled so that a more accurate ratio of length to breadth has not been possible. Plate 8, fig. 4 shows a specimen with a girdle developed; in spite of several similarities to C. minor we prefer to record this as Canngia? sp.