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Impagidinium diversum
From Fensome et al., 2019:
Impagidinium diversum Duxbury, 2001, p.107–108, fig.9, nos.1–6. Holotype: Duxbury, 2001, fig.9, no.5. Age: late Barremian
(holotype caved into middle Barremian according to Duxbury, 2001, p.107).
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Original description (Duxbury, 2001):
Impagidinium diversum n. sp.
Holotype: Figure 9.5.
Type Locality: Well 14/30b-3 at 10360 ft (ditch cuttings), Middle Barremian (caved), E.F. L20.4.
Derivation of Name: From the Latin diversus, diverse - in reference to the variable crestal development of this species.
Diagnosis: A small, gonyaulacacean dinocyst species with a smooth, spheroidal endocyst, and a short, blunt apical structure is present in some
specimens. A paratabulation typical of the genus is outlined by fenestrate parasutural crests of very variable form. These range from fairly low, distally finely denticulate, often sinuous crests with many, small fenestrations to high, trabeculate structures. The archeopyle is single paraplate precingular (3").
Dimensions: Holotype: 48 x 47 μm
Overall: 53 (48) 45 x 59 (51) 43 μm
Specimens Measured – 6
Comments: The parasutural crests of this species show considerable variability, particularly in their height and in the character of the fenestra-
tions developed. They range from fairly low crests with numerous fenestrations (Figures 9.1-9.4) to very high crests with few fenestrations, effectively forming trabeculae (Figures 9.5, 9.6). There is a continuous gradation between these types, although the higher-crested types are very reminiscent of the genus Rotosphaeropsis DAVEY, 1988. Although the height of parasutural crests can vary significantly, the overall size of this species remains fairly constant, since there appear to be a consistent reduction in the size of the endocyst with increasing crestal height.
This species is restricted to the Late Barremian interval in the study area.
Impagidinium diversum Duxbury, 2001, p.107–108, fig.9, nos.1–6. Holotype: Duxbury, 2001, fig.9, no.5. Age: late Barremian
(holotype caved into middle Barremian according to Duxbury, 2001, p.107).
---------------------------------------------------------------------------------------------------
Original description (Duxbury, 2001):
Impagidinium diversum n. sp.
Holotype: Figure 9.5.
Type Locality: Well 14/30b-3 at 10360 ft (ditch cuttings), Middle Barremian (caved), E.F. L20.4.
Derivation of Name: From the Latin diversus, diverse - in reference to the variable crestal development of this species.
Diagnosis: A small, gonyaulacacean dinocyst species with a smooth, spheroidal endocyst, and a short, blunt apical structure is present in some
specimens. A paratabulation typical of the genus is outlined by fenestrate parasutural crests of very variable form. These range from fairly low, distally finely denticulate, often sinuous crests with many, small fenestrations to high, trabeculate structures. The archeopyle is single paraplate precingular (3").
Dimensions: Holotype: 48 x 47 μm
Overall: 53 (48) 45 x 59 (51) 43 μm
Specimens Measured – 6
Comments: The parasutural crests of this species show considerable variability, particularly in their height and in the character of the fenestra-
tions developed. They range from fairly low crests with numerous fenestrations (Figures 9.1-9.4) to very high crests with few fenestrations, effectively forming trabeculae (Figures 9.5, 9.6). There is a continuous gradation between these types, although the higher-crested types are very reminiscent of the genus Rotosphaeropsis DAVEY, 1988. Although the height of parasutural crests can vary significantly, the overall size of this species remains fairly constant, since there appear to be a consistent reduction in the size of the endocyst with increasing crestal height.
This species is restricted to the Late Barremian interval in the study area.