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Wetzeliella astra
From Fensome et al., 2019:
Wetzeliella astra Denison in Costa et al., 1978, p.263, text-fig.2.
Holotype: Costa et al., 1978, text-fig.2; Jolley and Spinner, 1989, pl.1, figs.3–4.
NOW Dracodinium. Originally Wetzeliella, subsequently (and now) Dracodinium. NIA.
Age: Early Eocene.
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Synonyms:
1966 Wetzeliella (Wetzeliella) ovalis Eisenack, Williams & Downie, p. 192, pl. 18, fig. 10.
1969 Wetzeliella sp. 1, Gocht, pp. 2t-2, pl. 10, fig. 8;
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.
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Emende description Denison, 2021
Emended diagnosis. Dorso-ventrally compressed cysts with rounded pentagonal outline produced into five horns, which can be well developed to quite subdued, but typically with a larger left antapical horn. Circumcavate; pericoel may be narrow between horns. Intercalary archaeopyle, narrow and short. Operculum may be attached anteriorly, the archaeopyle appearing soleiform (Fig. 4a, d and j), or peri- and endo-operculum may be detached, the archaeopyle then appearing equipeliform (Fig. 4c, e and g). Cingulum not clearly delineated but laevo-rotatory, indicated by offset of lateral horns. Processes distally free, non-tabular, arising from a broad base and tapering to a closed tip. Processes are mostly single, but may bifurcate or rarely trifurcate, either near the base or at variable distances along the process. Process terminations have radiating tapering spines, as few as two or three, more commonly five or six, slightly to markedly recurved, up to 2 µm in length.
Discussion. The emendation is to emphasize the variability of the operculum and the nature of the processes. Transfer to Dracodinium by Williams et al. (2015) is rejected, as that genus has a latipeliform archaeopyle, in which periarchaeopyle and endarchaeopyle are relatively broad.
Wetzeliella astra Denison in Costa et al., 1978, p.263, text-fig.2.
Holotype: Costa et al., 1978, text-fig.2; Jolley and Spinner, 1989, pl.1, figs.3–4.
NOW Dracodinium. Originally Wetzeliella, subsequently (and now) Dracodinium. NIA.
Age: Early Eocene.
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Synonyms:
1966 Wetzeliella (Wetzeliella) ovalis Eisenack, Williams & Downie, p. 192, pl. 18, fig. 10.
1969 Wetzeliella sp. 1, Gocht, pp. 2t-2, pl. 10, fig. 8;
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.
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Emende description Denison, 2021
Emended diagnosis. Dorso-ventrally compressed cysts with rounded pentagonal outline produced into five horns, which can be well developed to quite subdued, but typically with a larger left antapical horn. Circumcavate; pericoel may be narrow between horns. Intercalary archaeopyle, narrow and short. Operculum may be attached anteriorly, the archaeopyle appearing soleiform (Fig. 4a, d and j), or peri- and endo-operculum may be detached, the archaeopyle then appearing equipeliform (Fig. 4c, e and g). Cingulum not clearly delineated but laevo-rotatory, indicated by offset of lateral horns. Processes distally free, non-tabular, arising from a broad base and tapering to a closed tip. Processes are mostly single, but may bifurcate or rarely trifurcate, either near the base or at variable distances along the process. Process terminations have radiating tapering spines, as few as two or three, more commonly five or six, slightly to markedly recurved, up to 2 µm in length.
Discussion. The emendation is to emphasize the variability of the operculum and the nature of the processes. Transfer to Dracodinium by Williams et al. (2015) is rejected, as that genus has a latipeliform archaeopyle, in which periarchaeopyle and endarchaeopyle are relatively broad.