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Kiokansium hesperus
Kiokansium hesperus (Davey, 1979) Stover and Williams, 1987
Now Nexosispinum. Originally (and now) Nexosispinum, subsequently Kiokansium. Prössl, 1990, retained this species in Nexosispinum Davey, 1979.
Holotype: Davey, 1979, pl.6, fig.5
Age: Aptian-Albian
Original description (davey, 1979):
Nexosispinum hesperum sp. nov. (Plate 6, Figures 1-5)
Derivation of name: Latin, hesperus, west — with reference to the westerly occurrence of this species relative to Europe.
Diagnosis: A species of Nexosispinum possessing a thin, lightly punctate or intraperforate wall. Simple processes are common; others anastomoze in an uncomplicated manner with one or two neighboring processes. The anastomozing is generally proximal or medial. The processes are either irregularly arranged over the cyst surface or they sometimes occur in small clumps or alignments. Distally, they are generally capitate or briefly bifurcate. An archeopyle is normally present.
Holotype: MPK 1723, DSDP Leg 48, Hole 402A, Sample 15-6, 23-26 cm. Albian, northern Bay of Biscay.
Dimensions: Endocyst diameter, holotype: 40 × 41 µm, range: 38 (47) 69 µm. Process length, holotype 6-7 µm, range 6-9 µm.
Description: The thickness of the cyst wall and the processes are both about 0.5 µm. The exact shape of the archeopyle is normally very difficult to discern because of cyst distortion; occasionally the operculum remains in position.
Remarks: N. hesperum sp. nov. differs from N. vetusculum comb. nov. by having a punctate wall and by the processes which are fewer in number, shorter, and less complexly linked. N. vetusculum has not been recorded above the early Barremian of England (Davey, 1974; Duxbury, 1977).
Now Nexosispinum. Originally (and now) Nexosispinum, subsequently Kiokansium. Prössl, 1990, retained this species in Nexosispinum Davey, 1979.
Holotype: Davey, 1979, pl.6, fig.5
Age: Aptian-Albian
Original description (davey, 1979):
Nexosispinum hesperum sp. nov. (Plate 6, Figures 1-5)
Derivation of name: Latin, hesperus, west — with reference to the westerly occurrence of this species relative to Europe.
Diagnosis: A species of Nexosispinum possessing a thin, lightly punctate or intraperforate wall. Simple processes are common; others anastomoze in an uncomplicated manner with one or two neighboring processes. The anastomozing is generally proximal or medial. The processes are either irregularly arranged over the cyst surface or they sometimes occur in small clumps or alignments. Distally, they are generally capitate or briefly bifurcate. An archeopyle is normally present.
Holotype: MPK 1723, DSDP Leg 48, Hole 402A, Sample 15-6, 23-26 cm. Albian, northern Bay of Biscay.
Dimensions: Endocyst diameter, holotype: 40 × 41 µm, range: 38 (47) 69 µm. Process length, holotype 6-7 µm, range 6-9 µm.
Description: The thickness of the cyst wall and the processes are both about 0.5 µm. The exact shape of the archeopyle is normally very difficult to discern because of cyst distortion; occasionally the operculum remains in position.
Remarks: N. hesperum sp. nov. differs from N. vetusculum comb. nov. by having a punctate wall and by the processes which are fewer in number, shorter, and less complexly linked. N. vetusculum has not been recorded above the early Barremian of England (Davey, 1974; Duxbury, 1977).