Back
Dracodinium astra
Dracodinium astra (Denison in Costa et al., 1978, p.263, text-fig.2) Williams et al., 2015, p.304.
Originally Wetzeliella, subsequently (and now) Dracodinium.
Holotype: Costa et al., 1978, text-fig.2; Jolley and Spinner, 1989, pl.1, figs.3–4.
Age: early Eocene.
Original Diagnosis: Costa et al. 1978, p. 263
A species of Wetzeliella with a rounded- pentagonal pericyst produced into five small horns, of which the right antapical horn is strongly reduced. Thin-walled endocyst, separated from the pericyst by a distinct though narrow pericoel. Periphragm bearing abundant hollow intratabular processes, distally open, flaring into 4-7 (usually 6) secae. Peri- and endo-archeopyle subquadrangular, type I/I (2a/2a), the periarcheopyle being slightly more elongate in the axial direction than the endoarcheopyle.
Dimensions. Holotype: pericyst length 100 µm, breadth 98 µm; endocyst length 63 µm, breadth 66 µm; processes length 5-8 µm. Range: pericyst length 105-89 µm, breadth 103-85 µm; endocyst length 65-57 µm, breadth 69-6t µm: processes length 5-8 µm. Specimens measured: 9.
Remarks: Costa et al. 1978, p. 263
W. astra differs from W. aniculala Eisenack in its smaller size, narrower pericoel, denser ornament and strongly asymmetrical outline. W. meckelfeldensis Gocht and W. Iunaris Gocht are larger, have longer horns, and a periarcheopyle distinctly more elongate than the endoarcheopyle. W astra is closely similar in shape to, and presumably derives from, W (Apectodinium) paniculata Costa & Downie. The latter lacks the distinct pericoel of W. astra and the processes do not show the characteristic distal terminations of W astra. W. astra is the oldest typical Wetzeliella known so far and is probably a link between Welzeliella (Wetzeliella) and Wetzeliella (Apectodinium).
Distribution. Lower London Clay, SE England; Unter Eozan 1, Meckelfeld, N Germany; Formation de Varengeville (lower part), Phare d Ailly, near Dieppe, France.
Originally Wetzeliella, subsequently (and now) Dracodinium.
Holotype: Costa et al., 1978, text-fig.2; Jolley and Spinner, 1989, pl.1, figs.3–4.
Age: early Eocene.
Original Diagnosis: Costa et al. 1978, p. 263
A species of Wetzeliella with a rounded- pentagonal pericyst produced into five small horns, of which the right antapical horn is strongly reduced. Thin-walled endocyst, separated from the pericyst by a distinct though narrow pericoel. Periphragm bearing abundant hollow intratabular processes, distally open, flaring into 4-7 (usually 6) secae. Peri- and endo-archeopyle subquadrangular, type I/I (2a/2a), the periarcheopyle being slightly more elongate in the axial direction than the endoarcheopyle.
Dimensions. Holotype: pericyst length 100 µm, breadth 98 µm; endocyst length 63 µm, breadth 66 µm; processes length 5-8 µm. Range: pericyst length 105-89 µm, breadth 103-85 µm; endocyst length 65-57 µm, breadth 69-6t µm: processes length 5-8 µm. Specimens measured: 9.
Remarks: Costa et al. 1978, p. 263
W. astra differs from W. aniculala Eisenack in its smaller size, narrower pericoel, denser ornament and strongly asymmetrical outline. W. meckelfeldensis Gocht and W. Iunaris Gocht are larger, have longer horns, and a periarcheopyle distinctly more elongate than the endoarcheopyle. W astra is closely similar in shape to, and presumably derives from, W (Apectodinium) paniculata Costa & Downie. The latter lacks the distinct pericoel of W. astra and the processes do not show the characteristic distal terminations of W astra. W. astra is the oldest typical Wetzeliella known so far and is probably a link between Welzeliella (Wetzeliella) and Wetzeliella (Apectodinium).
Distribution. Lower London Clay, SE England; Unter Eozan 1, Meckelfeld, N Germany; Formation de Varengeville (lower part), Phare d Ailly, near Dieppe, France.