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Druggidium confirmatum
Plate 16, Figures 17, 18, 24
Druggidium sp. in Harding 1986b, p. 24, Pl. 3, Figs. 4-14
Holotype: Plate 16, Figure 18
Type Locality: late Hauterivian, Speeton Clay Formation, marginatus ammonite Zone. Holotype: Slide midC3(4), E.F. X44.0.
Derivation of Name: From the Latin confirmatum, strengthened, fortified – in reference to the robust nature of this species, particularly the well-developed crestal thickenings.
Diagnosis: Asmall, spherical to broadly ellipsoidal species with a clear tabulation apparently typical for the genus. Tabulation is expressed as thick, low, distally entire, strong surface ridges which are of similar height over the entire cyst; the cyst outline shows some gonal angularity. A spatulate sulcal area and a broad, distinct cingulum are clearly expressed, the latter separating a squat epicyst and a longer hypocyst. Surface sculpture is alveolate, typically resembling a clear reticulum over the entire cyst. The archeopyle involves plates 3'' and 4''.
Dimensions: Holotype: Length - 20 μm. Width - 18 μm. Overall: 28 (24) 20 μm × 25 (22) 18 μm. Specimens Measured: 8.
Remarks: This species was included in Harding 1986b as Druggidium sp. from the Otto Gott clay pit, Sarstedt, Lower Saxony Basin, with the following measurements: Length: 25 (20.5) 16 μm, Width: 23 (17.9) 13 μm (26 specimens measured); Harding’s specimens are therefore smaller than those at Speeton.
In his remarks, Harding (1986b, p. 24) stated that, “This species bears some resemblance to Druggidium deflandrei (Millioud) Habib. The electron micrograph of this species illustrated by Habib (1973, pl. 3, Fig. 4) shows an alveolate surface sculpture very like that of D. sp.”. He also stated that, “ The present specimens compared with the description of D. deflandrei are smaller, less anteroposteriorly elongated and have a higher C.I. (cingulum index)”.
Considering the archeopyle type demonstrated by this species, Harding (op. cit.) remarked that, “The archaeopyle seems to be a 2P type with the paraplates involved (3''' [4i] (sic) and 4"[4u]) sometimes remaining adherent adcingularly. However the adjacent precingular paraplates (2"[3] and 5"[5]) often appear torn and the remaining epicystal paraplates collapse inwards making interpretation difficult. Tabulation is of the D. jubatum type (i.e. 7"[li] somewhat reduced but still in contact with 6c[fi] -Evitt 1985, fig. 5. 18B)”.
Although all of his illustrations of “Druggidium sp.” (Harding 1986b, Pl. 3, Figs. 4-14) were from the Gott Clay Pit, Harding (op. cit., p. 24) stated that this species was, “a good marker for the latest Hauterivian to very earliest Barremian at Gott and Speeton”. Harding did not include this species in his 1990 publication (where the Gott and Speeton sections were described in detail), but comparison of Harding (1986b, p. 24) with Harding (1990, text-fig. 2) shows that his 1986b specimens range from his sample 50/1/79 (gottschei Zone - Harding’s deepest sample at Gott) to his sample 100/1/83 (Aulacoteuthis Zone). Contrary to Harding’s assertion, this covers much of the late Hauterivian and early Barremian. In the present study, D. confirmatum was recorded at Speeton between Beds C4C and LB2D (late Hauterivian to early Barremian, gottschei to fissicostatum Zones), a very similar range, although it was rare below Bed LB5D (early Barremian, rarocinctum Zone).
Druggidium sp. in Harding 1986b, p. 24, Pl. 3, Figs. 4-14
Holotype: Plate 16, Figure 18
Type Locality: late Hauterivian, Speeton Clay Formation, marginatus ammonite Zone. Holotype: Slide midC3(4), E.F. X44.0.
Derivation of Name: From the Latin confirmatum, strengthened, fortified – in reference to the robust nature of this species, particularly the well-developed crestal thickenings.
Diagnosis: Asmall, spherical to broadly ellipsoidal species with a clear tabulation apparently typical for the genus. Tabulation is expressed as thick, low, distally entire, strong surface ridges which are of similar height over the entire cyst; the cyst outline shows some gonal angularity. A spatulate sulcal area and a broad, distinct cingulum are clearly expressed, the latter separating a squat epicyst and a longer hypocyst. Surface sculpture is alveolate, typically resembling a clear reticulum over the entire cyst. The archeopyle involves plates 3'' and 4''.
Dimensions: Holotype: Length - 20 μm. Width - 18 μm. Overall: 28 (24) 20 μm × 25 (22) 18 μm. Specimens Measured: 8.
Remarks: This species was included in Harding 1986b as Druggidium sp. from the Otto Gott clay pit, Sarstedt, Lower Saxony Basin, with the following measurements: Length: 25 (20.5) 16 μm, Width: 23 (17.9) 13 μm (26 specimens measured); Harding’s specimens are therefore smaller than those at Speeton.
In his remarks, Harding (1986b, p. 24) stated that, “This species bears some resemblance to Druggidium deflandrei (Millioud) Habib. The electron micrograph of this species illustrated by Habib (1973, pl. 3, Fig. 4) shows an alveolate surface sculpture very like that of D. sp.”. He also stated that, “ The present specimens compared with the description of D. deflandrei are smaller, less anteroposteriorly elongated and have a higher C.I. (cingulum index)”.
Considering the archeopyle type demonstrated by this species, Harding (op. cit.) remarked that, “The archaeopyle seems to be a 2P type with the paraplates involved (3''' [4i] (sic) and 4"[4u]) sometimes remaining adherent adcingularly. However the adjacent precingular paraplates (2"[3] and 5"[5]) often appear torn and the remaining epicystal paraplates collapse inwards making interpretation difficult. Tabulation is of the D. jubatum type (i.e. 7"[li] somewhat reduced but still in contact with 6c[fi] -Evitt 1985, fig. 5. 18B)”.
Although all of his illustrations of “Druggidium sp.” (Harding 1986b, Pl. 3, Figs. 4-14) were from the Gott Clay Pit, Harding (op. cit., p. 24) stated that this species was, “a good marker for the latest Hauterivian to very earliest Barremian at Gott and Speeton”. Harding did not include this species in his 1990 publication (where the Gott and Speeton sections were described in detail), but comparison of Harding (1986b, p. 24) with Harding (1990, text-fig. 2) shows that his 1986b specimens range from his sample 50/1/79 (gottschei Zone - Harding’s deepest sample at Gott) to his sample 100/1/83 (Aulacoteuthis Zone). Contrary to Harding’s assertion, this covers much of the late Hauterivian and early Barremian. In the present study, D. confirmatum was recorded at Speeton between Beds C4C and LB2D (late Hauterivian to early Barremian, gottschei to fissicostatum Zones), a very similar range, although it was rare below Bed LB5D (early Barremian, rarocinctum Zone).