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Spiniferites multispinulus
Spiniferites multispinulus Pearce, 2010, p.55–56, pl.7, figs.1–6.
Holotype: Pearce, 2010, pl.7, figs.1–6.
Type locality and horizon. Trunch borehole, Norfolk, UK; 269.9–270.0 m, Burnham–Flamborough Chalk (undifferentiated), low Gonioteuthis quadrata Zone (mid-lower Campanian).
Age: middle early Campanian.
Diagnosis (Pearce, 2010). A species of Spiniferites consistently possessing two intergonal spines on the pre- and postcingular paraplates which are close to half the diameter of the central body in length.
Description. Small to medium-sized, spiniferate chorate dinoflagellate with a prolate ellipsoid central body. The wall is two-layered, comprising a thin (w0.5 μm) and smooth endophragm and a thin (w0.5 μm) and smooth periphragm, the latter of which develops partially hollow processes. Trifurcating gonal and bifurcating intergonal processes are typically around half the diameter of the central body in length (with furcations up 6 μm in length), and terminate in a minute bifurcation (<1 μm long). Gonal processes often possess a single vacuole at the mid-length. Two intergonal processes are consistently present on the lateral boundaries of the larger pre- and postcingular paraplates. The processes are united proximally by well-developed parasutural crests, highest against the processes and which may reach 6 μm high in between, particularly those at the paracingulum, and clearly delineate the standard gonyaulacacean paratabulation. The paracingulum is weakly laevorotatory, typically by one paracingulum width; the parasulcus lacks clearly developed parasutures. The archaeopyle is precingular (Type 1P, operculum detached) and formed by the loss of the third precingular paraplate (3").
Comparison. Differs from all other species of Spiniferites by consistently possessing two intergonal processes on the lateral margins of the pre- and postcingular paraplates.
Holotype: Pearce, 2010, pl.7, figs.1–6.
Type locality and horizon. Trunch borehole, Norfolk, UK; 269.9–270.0 m, Burnham–Flamborough Chalk (undifferentiated), low Gonioteuthis quadrata Zone (mid-lower Campanian).
Age: middle early Campanian.
Diagnosis (Pearce, 2010). A species of Spiniferites consistently possessing two intergonal spines on the pre- and postcingular paraplates which are close to half the diameter of the central body in length.
Description. Small to medium-sized, spiniferate chorate dinoflagellate with a prolate ellipsoid central body. The wall is two-layered, comprising a thin (w0.5 μm) and smooth endophragm and a thin (w0.5 μm) and smooth periphragm, the latter of which develops partially hollow processes. Trifurcating gonal and bifurcating intergonal processes are typically around half the diameter of the central body in length (with furcations up 6 μm in length), and terminate in a minute bifurcation (<1 μm long). Gonal processes often possess a single vacuole at the mid-length. Two intergonal processes are consistently present on the lateral boundaries of the larger pre- and postcingular paraplates. The processes are united proximally by well-developed parasutural crests, highest against the processes and which may reach 6 μm high in between, particularly those at the paracingulum, and clearly delineate the standard gonyaulacacean paratabulation. The paracingulum is weakly laevorotatory, typically by one paracingulum width; the parasulcus lacks clearly developed parasutures. The archaeopyle is precingular (Type 1P, operculum detached) and formed by the loss of the third precingular paraplate (3").
Comparison. Differs from all other species of Spiniferites by consistently possessing two intergonal processes on the lateral margins of the pre- and postcingular paraplates.