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Unipontidinium
From Fensome et al., 2019:
Unipontidinium Wrenn, 1988, p.148. Type: Piasecki, 1980, pl.1, figs.1–3, as Nematosphaeropsis aquaeductus.
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Original description: [Wrenn, 1988]:
Diagnosis:
Subspherical dinocyst with two wall layers. The central body gives rise to processes (gonal, or gonal and intergonal) that are joined at their distal terminations by single parasutural trabeculae.
Processes may or may not be joined proximally by parasutural features on the central body.
Paratabulation formula is 3-4`, 6``, 6c, 5-6```, 1p, 1````.
Parasulcal paraplates may be present.
The precingular archeopyle (Type P) is formed by the loss of the 3`` paraplate.
Affinities:
Unipontidinium differs from Spiniferites by having its processes joined distally by trabeculae, from Nematosphaeropsis by having single parasutural trabeculae rather than pairs of penitabular trabeculae joining adjacent processes, and from Cannosphaeropsis by having parasutural trabeculae joining processes at their distal terminations, rather than along the process shafts, proximal of their distal termination. Some species of Unipontidinium also bear well-developed parasutural ridges on the central body connecting the bases of adjacent processes. Unipontidinium differs from Impagidinium by having processes, trabeculae and parasutural features (on some species) delineating paratabulation, rather than only parasutural ridges or membranes, as on the latter genus.
Comments:
Unipontidinium is part of a dinocyst complex that includes the genera Impagidinium, Spiniferites and Nematosphaeropsis. These genera exhibit the same or very similar paratabulation formula (where paratabulation is evident), and differ primarily in the expression of parasutural and paratabular development.
Unipontidinium Wrenn, 1988, p.148. Type: Piasecki, 1980, pl.1, figs.1–3, as Nematosphaeropsis aquaeductus.
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Original description: [Wrenn, 1988]:
Diagnosis:
Subspherical dinocyst with two wall layers. The central body gives rise to processes (gonal, or gonal and intergonal) that are joined at their distal terminations by single parasutural trabeculae.
Processes may or may not be joined proximally by parasutural features on the central body.
Paratabulation formula is 3-4`, 6``, 6c, 5-6```, 1p, 1````.
Parasulcal paraplates may be present.
The precingular archeopyle (Type P) is formed by the loss of the 3`` paraplate.
Affinities:
Unipontidinium differs from Spiniferites by having its processes joined distally by trabeculae, from Nematosphaeropsis by having single parasutural trabeculae rather than pairs of penitabular trabeculae joining adjacent processes, and from Cannosphaeropsis by having parasutural trabeculae joining processes at their distal terminations, rather than along the process shafts, proximal of their distal termination. Some species of Unipontidinium also bear well-developed parasutural ridges on the central body connecting the bases of adjacent processes. Unipontidinium differs from Impagidinium by having processes, trabeculae and parasutural features (on some species) delineating paratabulation, rather than only parasutural ridges or membranes, as on the latter genus.
Comments:
Unipontidinium is part of a dinocyst complex that includes the genera Impagidinium, Spiniferites and Nematosphaeropsis. These genera exhibit the same or very similar paratabulation formula (where paratabulation is evident), and differ primarily in the expression of parasutural and paratabular development.