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Spiniferites vermiculatus
Derivation of name. The species epithet vermiculatus (Latin for ‘worm-like’) refers to the coarse, irregular vermiculate ornamentation characteristic of the cyst surface.
Holotype. Plate 6, figure 1; from a cuttings sample at 2460m, well 25/10-17S. Cyst size with processes 62um, length =47um, width =39um, process length =10um.
Type locality. Norwegian North Sea Quad 25.
Diagnosis. Cyst spherical to sub-spherical with a moderately thick wall (up to 1–2 mm), ornamented with coarse, low, irregular vermiculate sculpture. Processes are gonal and intergonal, varying in number across plates, solid or fibrous, proximally united by a thin membranous crest. Distally, processes are characteristically bi- and/or trifurcate with bifid terminations. Archeopyle is precingular, formed by the displacement of plate 3''.
Description. Intermediate-sized, proximochorate dinoflagellate cyst, spherical to sub-spherical in shape, typically exhibiting strong dorso-ventral compression. The cyst wall is composed of two closely adpressed layers: a thin, smooth periphragm and a thicker endophragm ornamented with coarse, low, irregular vermiculate sculpture. Processes are predominantly gonal, solid or fibrous in appearance, with their number and size varying between plates. Proximally, the processes are united by a thin membranous sutural crest. Distally, they are bi- to trifurcate, terminating in bifid apices. Tabulation is generally obscured due to surface folding. The archeopyle is precingular, formed by the loss of plate 300, and the operculum is frequently detached.
Dimensions. Cyst diameter (with processes): 57 (66) 79 mm; cyst diameter (without processes): 42 (48) 57 mm; process length 8 (10) 11 mm; number of specimens measured: 16.
Comparison. Spiniferites vermiculatus sp. nov. is distinguished by its coarse vermiculate ornamentation and bifurcate to trifurcate processes. It closely resembles Spiniferites crassus sp. nov. but differs in its pronounced surface sculpture and slightly larger cyst size. The unique vermiculate ornamentation provides a clear diagnostic character separating it from other members of the genus.
Remarks. This species was first recognized and recorded in the 1990s by palynologists at Ichron Limited (now Petrostrat Limited), under the informal designation Spiniferites ‘vermiculata’. It was observed within Thanetian sediments of the Lista Formation in the North Sea Basin. Spiniferites vermiculatus sp. nov. represents a particularly useful biostratigraphical marker within the Lista Formation due to its relatively high abundance and restricted stratigraphical range (see Figure 1).
Holotype. Plate 6, figure 1; from a cuttings sample at 2460m, well 25/10-17S. Cyst size with processes 62um, length =47um, width =39um, process length =10um.
Type locality. Norwegian North Sea Quad 25.
Diagnosis. Cyst spherical to sub-spherical with a moderately thick wall (up to 1–2 mm), ornamented with coarse, low, irregular vermiculate sculpture. Processes are gonal and intergonal, varying in number across plates, solid or fibrous, proximally united by a thin membranous crest. Distally, processes are characteristically bi- and/or trifurcate with bifid terminations. Archeopyle is precingular, formed by the displacement of plate 3''.
Description. Intermediate-sized, proximochorate dinoflagellate cyst, spherical to sub-spherical in shape, typically exhibiting strong dorso-ventral compression. The cyst wall is composed of two closely adpressed layers: a thin, smooth periphragm and a thicker endophragm ornamented with coarse, low, irregular vermiculate sculpture. Processes are predominantly gonal, solid or fibrous in appearance, with their number and size varying between plates. Proximally, the processes are united by a thin membranous sutural crest. Distally, they are bi- to trifurcate, terminating in bifid apices. Tabulation is generally obscured due to surface folding. The archeopyle is precingular, formed by the loss of plate 300, and the operculum is frequently detached.
Dimensions. Cyst diameter (with processes): 57 (66) 79 mm; cyst diameter (without processes): 42 (48) 57 mm; process length 8 (10) 11 mm; number of specimens measured: 16.
Comparison. Spiniferites vermiculatus sp. nov. is distinguished by its coarse vermiculate ornamentation and bifurcate to trifurcate processes. It closely resembles Spiniferites crassus sp. nov. but differs in its pronounced surface sculpture and slightly larger cyst size. The unique vermiculate ornamentation provides a clear diagnostic character separating it from other members of the genus.
Remarks. This species was first recognized and recorded in the 1990s by palynologists at Ichron Limited (now Petrostrat Limited), under the informal designation Spiniferites ‘vermiculata’. It was observed within Thanetian sediments of the Lista Formation in the North Sea Basin. Spiniferites vermiculatus sp. nov. represents a particularly useful biostratigraphical marker within the Lista Formation due to its relatively high abundance and restricted stratigraphical range (see Figure 1).