Back
Kallosphaeridium brevibarbatum
From Fensome et al., 2019:
Kallosphaeridium brevibarbatum de Coninck, 1969, p.44–45, pl.13, figs.14–15. Emendation: Jan du Chêne et al., 1985a, p.10. Holotype: de Coninck, 1969, pl.13, figs.14–15; Jan du Chêne et al., 1985a, pl.1, fig.3; text-fig.4A. Age: Early Eocene.
---------------------------------------------------------------------------------------------------
Original description (De Coninck, 1968):
Kallosphaeridium brevibarbatum nov. sp. (Pl. XIII, fig. I l cl 1J.)
Holotype. — Kallo -315 m. Preparation 5; coord. 34.7-103.5.
Diagnosis. — The body is globose. Its wall is thick, covered with innumerable dense and very short hairs. The archaeopyl is apical and the operculum is attached. Possible accessory sutures of the archaeopyl indicate six precingulate plates from which the operculum has detached.
Body dimensions: about 60 µm
Hair length: about 4 µm
Total wingspan: 68 µm
Remarks. — Of the two individuals found, only one is fairly well preserved. Its characteristic archaeopyle allowed me to conclude that it belongs to the Dinophyceae. The archaeopyle is of a type close to that of Forma L in EVITT, 1967, Stanf. Publ. Geol. Sc., 10, nr. 3, pl. 1, fig. 15, which has an apical archaeopyle with the operculum attached and accessory sutures that reveal the existence of the precingulate plates. However, in Forma L, only 5 precingulate plates detached from the operculum can be seen in the photo. This differentiates it from the genus Kallosphaeridium.
---------------------------------------------------------------------------------------------------
Jan du Chene et al. 1985a, p. 10
The following emendation incorporates the characteristics stated in the original description (De Coninck, 1969, p. 44) plus information from recent observations of the type and other specimens.
Emended description: Jan du Chene et al. 1985a, p. 10
Subspherical proximate cysts with a homogeneous untextured, thin (about 0.5 Ám) endophragm and a thicker (about 1.5 Ám) appressed periphragm. Periphragm has an internal granular appearance and externally bears a dense cover of slender, hairlike projections up to 4 Ám in length. Paratabulation is expressed by the principal and accessory archeopyle sutures which indicate a formula of 4", la, 6" for the epicyst. In the precingular series, 2" is typically four-sided, 1", 3"-6" are five-sided. Hypocystal paratabulation, paracingulum and parasulcus are not expressed. Archeopyle type [4AI]@; opercula are small relative to cyst diameter; OW/CD ratio = 0.41 to 0.29. Constituent opercular paraplate boundaries marked by short accessory archeopyle sutures and faint parasutural features on some specimens (pl. 1, fig. 7 - 10); preapical paraplate(s) not indicated. Diameter, between 45 and 70 Ám; 10 specimens measured.
Kallosphaeridium brevibarbatum de Coninck, 1969, p.44–45, pl.13, figs.14–15. Emendation: Jan du Chêne et al., 1985a, p.10. Holotype: de Coninck, 1969, pl.13, figs.14–15; Jan du Chêne et al., 1985a, pl.1, fig.3; text-fig.4A. Age: Early Eocene.
---------------------------------------------------------------------------------------------------
Original description (De Coninck, 1968):
Kallosphaeridium brevibarbatum nov. sp. (Pl. XIII, fig. I l cl 1J.)
Holotype. — Kallo -315 m. Preparation 5; coord. 34.7-103.5.
Diagnosis. — The body is globose. Its wall is thick, covered with innumerable dense and very short hairs. The archaeopyl is apical and the operculum is attached. Possible accessory sutures of the archaeopyl indicate six precingulate plates from which the operculum has detached.
Body dimensions: about 60 µm
Hair length: about 4 µm
Total wingspan: 68 µm
Remarks. — Of the two individuals found, only one is fairly well preserved. Its characteristic archaeopyle allowed me to conclude that it belongs to the Dinophyceae. The archaeopyle is of a type close to that of Forma L in EVITT, 1967, Stanf. Publ. Geol. Sc., 10, nr. 3, pl. 1, fig. 15, which has an apical archaeopyle with the operculum attached and accessory sutures that reveal the existence of the precingulate plates. However, in Forma L, only 5 precingulate plates detached from the operculum can be seen in the photo. This differentiates it from the genus Kallosphaeridium.
---------------------------------------------------------------------------------------------------
Jan du Chene et al. 1985a, p. 10
The following emendation incorporates the characteristics stated in the original description (De Coninck, 1969, p. 44) plus information from recent observations of the type and other specimens.
Emended description: Jan du Chene et al. 1985a, p. 10
Subspherical proximate cysts with a homogeneous untextured, thin (about 0.5 Ám) endophragm and a thicker (about 1.5 Ám) appressed periphragm. Periphragm has an internal granular appearance and externally bears a dense cover of slender, hairlike projections up to 4 Ám in length. Paratabulation is expressed by the principal and accessory archeopyle sutures which indicate a formula of 4", la, 6" for the epicyst. In the precingular series, 2" is typically four-sided, 1", 3"-6" are five-sided. Hypocystal paratabulation, paracingulum and parasulcus are not expressed. Archeopyle type [4AI]@; opercula are small relative to cyst diameter; OW/CD ratio = 0.41 to 0.29. Constituent opercular paraplate boundaries marked by short accessory archeopyle sutures and faint parasutural features on some specimens (pl. 1, fig. 7 - 10); preapical paraplate(s) not indicated. Diameter, between 45 and 70 Ám; 10 specimens measured.