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Dinogymnium circulos
Plate 4, Figures 17, 18, 22
Holotype: Plate 4, Figure 22
Type Locality: Vergol outcrop, early Valanginian, Bed V91M, inostranzewi ammonite Zone, inostranzewi Sub-zone. Holotype: Slide V91M(Schulze), E.F. P44.0.
Derivation of Name: From the Latin circulos, circle - in reference to the surface folds.
Diagnosis: A small, proximate, acavate species with an ovoidal to almost square ambitus. The epi- and hypocyst can be symmetrical or the epicyst may be longer than the hypocyst and narrow slightly towards the apex. The test wall is thin and smooth, without obvious trichocyst pores and bears a small number of sub-circular, unornamented ridges each with a small number of longitudinal ridges within them. The cingulum is broad and slightly indented. The "archeopyle" is apical.
Dimensions: Holotype 41 × 41 μm.
Overall 48 (44) 41 μm × 41 (37) 35 μm.
Specimens measured - 2.
Remarks: The sub-circular ridged areas displayed by Dinogymnium circulos n. sp. appear to be a unique feature within this genus. They are restricted to regions directly adjacent to the cingulum and may reflect pre- and post-cingular plate series. Only two specimens of this species were recorded here, but it is considered sufficiently distinctive to include as a new species. Both of the specimens recovered were from the early Valanginian, inostranzewi ammonite Zone, Beds V91M (inostranzewi Subzone) and V97M (platycostatus Sub-zone).
Holotype: Plate 4, Figure 22
Type Locality: Vergol outcrop, early Valanginian, Bed V91M, inostranzewi ammonite Zone, inostranzewi Sub-zone. Holotype: Slide V91M(Schulze), E.F. P44.0.
Derivation of Name: From the Latin circulos, circle - in reference to the surface folds.
Diagnosis: A small, proximate, acavate species with an ovoidal to almost square ambitus. The epi- and hypocyst can be symmetrical or the epicyst may be longer than the hypocyst and narrow slightly towards the apex. The test wall is thin and smooth, without obvious trichocyst pores and bears a small number of sub-circular, unornamented ridges each with a small number of longitudinal ridges within them. The cingulum is broad and slightly indented. The "archeopyle" is apical.
Dimensions: Holotype 41 × 41 μm.
Overall 48 (44) 41 μm × 41 (37) 35 μm.
Specimens measured - 2.
Remarks: The sub-circular ridged areas displayed by Dinogymnium circulos n. sp. appear to be a unique feature within this genus. They are restricted to regions directly adjacent to the cingulum and may reflect pre- and post-cingular plate series. Only two specimens of this species were recorded here, but it is considered sufficiently distinctive to include as a new species. Both of the specimens recovered were from the early Valanginian, inostranzewi ammonite Zone, Beds V91M (inostranzewi Subzone) and V97M (platycostatus Sub-zone).