Back
Apteodinium emslandense
From Fensome et al., 2019:
Apteodinium emslandense (Gerlach, 1961, p.172–173, pl.26, figs.13–14) Stover and Evitt, 1978, p.141. Emendation: Benedek and Sarjeant, 1981, p.316–318, as Apteodinium emslandense. Holotype: Gerlach, 1961, pl.26, fig.13; Benedek and Sarjeant, 1981, fig.1, no.1; Jan du Chêne et al., 1986a, pl.10, figs.17–19. Originally Emslandia, subsequently (and now) Apteodinium. Age: Middle Oligocene–Middle Miocene.
---------------------------------------------------------------------------------------------------
Original description as Emslandia emslandensis: [Gerlach, 1961, p. 172]: (Translation: LPP)
Diagnosis:
A species of the genus Emslandia with a thickened marginal membrane. Girdle furrow spiral, with a large offset of 2-3 girdle widths. Longitudinal furrow more or less clear ventrally on the hypotheca. Membrane finely punctate or with scarred surface.
Description:
The shape of the theca varies between spherical and elongated oval forms, which extend apically into a short lobe. The shape of these lobes can vary (Figs. 9 and 10). In some specimens, the apical process tapers gradually and ends distally in a small, quadrangular appendage. However, the majority of the forms are characterized by simpler lobes.
The margin is smooth, and only the distally tapered end shows a small notch.
The theca is surrounded dorsoventrally by a relatively delicate membrane,
as can be clearly seen when looking into a pyloma. In contrast, the marginal membrane is strongly bulged and thickens, reaching dimensions of up to 6 microns.
The epidermis and hypodermis are separated into almost equal-sized parts by a noticeably depressed girdle groove. The lateral edges of the theca appear clearly notched by the girdle groove. The longitudinal furrow runs ventrally along the hypodermis from the antapex to the ends of the transverse furrow, which are spaced apart by 2 to 3 furrow widths.
The sinus membrane appears finely punctured or scarred.
A trapezoidal archeopyle was always found, usually wider than it was high. It begins below the apical cusp and is bordered by the epithet by the girdle furrow. The exposed eversion covers could often be observed inside the carapaces. Thus, all specimens with archeopyles are abandoned shells from which the protoplast had already emerged.
Representatives of the genus Emslamdia are quite common in the Middle Miocene, Upper, and Middle Oligocene, but relatively few specimens show complete preservation or an ideal position for observation.
The coloration of the forms is yellow to brownish. No inner capsule was found in any of the specimens.
Dimensions:
Holotype: 94:69
Paratypes: 84:63, 80:53
Average: 87:67 (10 specimens)
------------------------------------------------------------------------------------------------------------------------------
Original description Emslandia emslandensis Gerlach, 1961:
Holotype Pr1170/26 (200), Plate 26 Fig. 13
Paratypes Pr1170/27 (666), Pr1170.28 (678) and Pr1170/80 (252)
Locus Typicus: Bohrung Emsburen 7.
Stratum Typicum: Middle Miocene; 134m height.
Derivation of name: "emslandensis", after the Emsland.
Diagnosis:
A species of the genus Emslandia with a bulbous, thickened marginal membrane. The girdle furrow is spiral, with a high offset of 2 to 3 furrow widths. The longitudinal groove is more or less distinct ventrally on the hypocyst. The membrane is finely punctured or has a pitted surface.
-------------------------------------------------------------------------------------
Emended diagnosis as Emslandia emslandensis:
Sarjeant and Benedek, 1981, p. 318:
Diagnosis:
Cyst proximate, ovoidal, with a short, blunt apical horn. Phragma thick, two-layered, the periphragm approximately four times as thick as the endophragm and further thickened at the apex, to form the apical horn. Paracingulum clearly defined by raised periphragmal ridges, its two ends offset by two to three times its width. Parasulcus defined posteriorly to the paracingulum by raised ridges, well or poorly marked, which diverge somewhat towards the antapex. Surface of periphragm generally finely punctate to irregularly scabrate, however, this ornament is reduced or absent on paracingulum and parasulcus.
Archaeopyle single-plate precingular, Type P.
Apteodinium emslandense (Gerlach, 1961, p.172–173, pl.26, figs.13–14) Stover and Evitt, 1978, p.141. Emendation: Benedek and Sarjeant, 1981, p.316–318, as Apteodinium emslandense. Holotype: Gerlach, 1961, pl.26, fig.13; Benedek and Sarjeant, 1981, fig.1, no.1; Jan du Chêne et al., 1986a, pl.10, figs.17–19. Originally Emslandia, subsequently (and now) Apteodinium. Age: Middle Oligocene–Middle Miocene.
---------------------------------------------------------------------------------------------------
Original description as Emslandia emslandensis: [Gerlach, 1961, p. 172]: (Translation: LPP)
Diagnosis:
A species of the genus Emslandia with a thickened marginal membrane. Girdle furrow spiral, with a large offset of 2-3 girdle widths. Longitudinal furrow more or less clear ventrally on the hypotheca. Membrane finely punctate or with scarred surface.
Description:
The shape of the theca varies between spherical and elongated oval forms, which extend apically into a short lobe. The shape of these lobes can vary (Figs. 9 and 10). In some specimens, the apical process tapers gradually and ends distally in a small, quadrangular appendage. However, the majority of the forms are characterized by simpler lobes.
The margin is smooth, and only the distally tapered end shows a small notch.
The theca is surrounded dorsoventrally by a relatively delicate membrane,
as can be clearly seen when looking into a pyloma. In contrast, the marginal membrane is strongly bulged and thickens, reaching dimensions of up to 6 microns.
The epidermis and hypodermis are separated into almost equal-sized parts by a noticeably depressed girdle groove. The lateral edges of the theca appear clearly notched by the girdle groove. The longitudinal furrow runs ventrally along the hypodermis from the antapex to the ends of the transverse furrow, which are spaced apart by 2 to 3 furrow widths.
The sinus membrane appears finely punctured or scarred.
A trapezoidal archeopyle was always found, usually wider than it was high. It begins below the apical cusp and is bordered by the epithet by the girdle furrow. The exposed eversion covers could often be observed inside the carapaces. Thus, all specimens with archeopyles are abandoned shells from which the protoplast had already emerged.
Representatives of the genus Emslamdia are quite common in the Middle Miocene, Upper, and Middle Oligocene, but relatively few specimens show complete preservation or an ideal position for observation.
The coloration of the forms is yellow to brownish. No inner capsule was found in any of the specimens.
Dimensions:
Holotype: 94:69
Paratypes: 84:63, 80:53
Average: 87:67 (10 specimens)
------------------------------------------------------------------------------------------------------------------------------
Original description Emslandia emslandensis Gerlach, 1961:
Holotype Pr1170/26 (200), Plate 26 Fig. 13
Paratypes Pr1170/27 (666), Pr1170.28 (678) and Pr1170/80 (252)
Locus Typicus: Bohrung Emsburen 7.
Stratum Typicum: Middle Miocene; 134m height.
Derivation of name: "emslandensis", after the Emsland.
Diagnosis:
A species of the genus Emslandia with a bulbous, thickened marginal membrane. The girdle furrow is spiral, with a high offset of 2 to 3 furrow widths. The longitudinal groove is more or less distinct ventrally on the hypocyst. The membrane is finely punctured or has a pitted surface.
-------------------------------------------------------------------------------------
Emended diagnosis as Emslandia emslandensis:
Sarjeant and Benedek, 1981, p. 318:
Diagnosis:
Cyst proximate, ovoidal, with a short, blunt apical horn. Phragma thick, two-layered, the periphragm approximately four times as thick as the endophragm and further thickened at the apex, to form the apical horn. Paracingulum clearly defined by raised periphragmal ridges, its two ends offset by two to three times its width. Parasulcus defined posteriorly to the paracingulum by raised ridges, well or poorly marked, which diverge somewhat towards the antapex. Surface of periphragm generally finely punctate to irregularly scabrate, however, this ornament is reduced or absent on paracingulum and parasulcus.
Archaeopyle single-plate precingular, Type P.