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Bacchidinium polypes ssp. clavulum
Bacchidinium polypes ssp. clavulum, (Davey, 1969), (Lentin and Williams, 1981)
Now Impletosphaeridium clavulum. Originally Cleistosphaeridium polypes var. clavulum, subsequently Cleistosphaeridium polypes subsp. clavulum, thirdly Impletosphaeridium polypes subsp. clavulum, fourthly Bacchidinium polypes subsp. clavulum, fifthly Cleistosphaeridium clavulum, sixthly Impletosphaeridium clavulum, seventhly (and now) Impletosphaeridium clavulum. This combination was not validly published in Davey (1979b, p.553), since that author did not fully reference the basionym.
Holotype: Davey, 1969, pl.6, fig.9
Occurrence: lowermost Cenomanian samples at Fetcham Mill and Compton Bay; previously recorded by Cookson & Hughes (I964) from Upper Albian-basal Cenomanian of England
Age: Cenomanian
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Original description as Cleistosphaeridium polypes var. clavulum: [Davey, 1969a, p. 154, 155]:
Diagnosis:
A variety of C. polypes possessing fine, capitate processes. Processes terminating with fine spines are extremely rare.
Dimensions:
Type: diameter of central body 29 by 32 µm, length of processes 12-13 µm.
Range: diameter of central body 29 (31.5) 39 µm, maximum length of processes 13 (14.7) 15 µ.m Numbers of specimens measured: 10.
Affinities/Remarks:
C. polypes var. clavulum differs from C. polypes in that the processes are capitate, the terminal bulge being flattened and resembling the head of a pin. Two specimens have been observed each possessing. One process of the type characteristic of C. polypes thus indicating a relationship between the two forms. C. polypes probably evolved from this variety, spiny processes replacing the capitate ones.
Now Impletosphaeridium clavulum. Originally Cleistosphaeridium polypes var. clavulum, subsequently Cleistosphaeridium polypes subsp. clavulum, thirdly Impletosphaeridium polypes subsp. clavulum, fourthly Bacchidinium polypes subsp. clavulum, fifthly Cleistosphaeridium clavulum, sixthly Impletosphaeridium clavulum, seventhly (and now) Impletosphaeridium clavulum. This combination was not validly published in Davey (1979b, p.553), since that author did not fully reference the basionym.
Holotype: Davey, 1969, pl.6, fig.9
Occurrence: lowermost Cenomanian samples at Fetcham Mill and Compton Bay; previously recorded by Cookson & Hughes (I964) from Upper Albian-basal Cenomanian of England
Age: Cenomanian
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Original description as Cleistosphaeridium polypes var. clavulum: [Davey, 1969a, p. 154, 155]:
Diagnosis:
A variety of C. polypes possessing fine, capitate processes. Processes terminating with fine spines are extremely rare.
Dimensions:
Type: diameter of central body 29 by 32 µm, length of processes 12-13 µm.
Range: diameter of central body 29 (31.5) 39 µm, maximum length of processes 13 (14.7) 15 µ.m Numbers of specimens measured: 10.
Affinities/Remarks:
C. polypes var. clavulum differs from C. polypes in that the processes are capitate, the terminal bulge being flattened and resembling the head of a pin. Two specimens have been observed each possessing. One process of the type characteristic of C. polypes thus indicating a relationship between the two forms. C. polypes probably evolved from this variety, spiny processes replacing the capitate ones.