Back
Triblastula wilsonii
From Fensome et al., 2019:
Triblastula wilsonii Slimani, 1994, p.60–62, pl.9, fig.3; pl.10, figs.10–12.
Holotype: Slimani, 1994, pl.10, figs.10–11.
Taxonomic junior synonym: Triblastula fibrata (name not validly published), according to Slimani (2001a, p.194).
Age: latest early to earliest late Maastrichtian.
---------------------------------------------------------------------------------------------------
Original description (Slimani, 1994): Translation PKB 2024
Triblastula wilsonii sp. nov. (P1.9, Fig.3, Pl. 10, Fig. 10-12)
Derivation of name: In honor of Dr. Graeme J. WILSON who first described the same type of cyst in his unpublished Ph.D. work.
Hololvpe: Turnhout -850.72 m, slide 1, EF coord. E46.
Type locality: Turnhout -850.72 m.
Typical horizon: Lower Maastrichtian.
Synonymy:
1974: Triblastulafibrata sp. nov. in Wilson, p. 164 - 165; pl. 10; fig. 2, 3, 6; text-fig. 27.
Diagnosis: Triblastula cyst, fibrous, with a wide apical and antapical pericoel; the apical part of the pericyst is dome-shaped and bears a short apical horn (10 to 14 µm in length and 10 µm in width) which is rounded and typically surmounted by a small solid papilla 2 to 3 µm in length. The antapical part with a subsquare and rounded outline bears a very discreet antapical protuberance less than 1 µm in size. The endophragm and periphragm are connected by filiform projections in the apical and antapical region. The paratabulation is vaguely indicated: 6", ?6c, 5'", 1"", xs. The archaeopyle is precingulate type P (3") with a free or attached operculum.
Description: The cyst is bicavate; the endocyst is ovoid to subspheroidal with a small apical protrusion (1 to 2 µm in length); The pericyst is elongated longitudinally with a broad apical pericoel and an antapical pericoel, of equal size (30 to 40 µm in length), which have slight constrictions near the anterior and posterior ends of the endocyst. The endophragm is quite thick (around 2 pm) and smooth. The periphragm is microreticulate with a generally fibrous appearance, and bears parasutural membranous ridges (up to 14 µm in height) higher at their junctions, particularly on the paracingulum, and often intercalated with hollow vesicles (2 to 20 µm in diameter). ) larger and more numerous especially on the paracingulum. The latter is wide (6 to 14 µm), laevotatory and marked by the alignment in a single row of vesicles and/or sometimes possible spines (6 to 14 µm) that are weakly developed. The parasulcus may have 2 to 3 short spines. Forms that lack spines probably show early beginnings of gonal processes indicated by an increase in the height of the ridges at the points of their gonal junctions. This slight variability is considered intraspecific because all intermediate forms are present in the material studied.
Dimensions: Holotype: maximum endocyst diameter: 70 µm; pericyst. length: 130 µm, width: 80 µm. Variations: endocyst diameter: 50 - 70 µm; pericyst, length: 80 - 130 µm, width: 70 - 80 µm. Number of specimens measured: 8.
Material: 12 copies.
Comparison: This species is very comparable to Triblastula fibrata in the unpublished work of WILSON (1974), this author mentioned in his remark p. 165 that he found rare specimens with weakly developed processes in the paracingulate region and he considered them as intermediate forms between T. fibrata and T. utinensis O. WETZEL (1933b) emend. SARJEANT (1985b); in the present work we group forms with and without processes into a single species. With the exception of its possible processes, T. wilsonii sp. nov. is distinguished from T. utinensis (Pl. 9, fig. 1,2) by its rounded pericyst in the apical and antapical region and especially by its dome-shaped apical part, by its shorter apical horn surmounted by a small papilla, by the presence of numerous vesicles mainly marking the paracingulum and also by the absence of a true antapical horn. T. utinensis has a pericyst of subpolygonal outline with an apical part almost in the form of a minaret (SARJEANT, 1985b: p. 139) extended by a much longer apical horn, and an antapical part provided with a more pronounced antapical horn; the processes are more numerous and more developed both on the paracingulum and elsewhere.
Stratigraphic distribution: Turnhout: -850.72 to -836.95 m, late Maastrichtian inf. - early upper Maastrichtian. In WILSO N (1974), Maastrichtian inf. (occidentalis/lanceolata Zone), Hvidskud. Klint, Denmark.
Triblastula wilsonii Slimani, 1994, p.60–62, pl.9, fig.3; pl.10, figs.10–12.
Holotype: Slimani, 1994, pl.10, figs.10–11.
Taxonomic junior synonym: Triblastula fibrata (name not validly published), according to Slimani (2001a, p.194).
Age: latest early to earliest late Maastrichtian.
---------------------------------------------------------------------------------------------------
Original description (Slimani, 1994): Translation PKB 2024
Triblastula wilsonii sp. nov. (P1.9, Fig.3, Pl. 10, Fig. 10-12)
Derivation of name: In honor of Dr. Graeme J. WILSON who first described the same type of cyst in his unpublished Ph.D. work.
Hololvpe: Turnhout -850.72 m, slide 1, EF coord. E46.
Type locality: Turnhout -850.72 m.
Typical horizon: Lower Maastrichtian.
Synonymy:
1974: Triblastulafibrata sp. nov. in Wilson, p. 164 - 165; pl. 10; fig. 2, 3, 6; text-fig. 27.
Diagnosis: Triblastula cyst, fibrous, with a wide apical and antapical pericoel; the apical part of the pericyst is dome-shaped and bears a short apical horn (10 to 14 µm in length and 10 µm in width) which is rounded and typically surmounted by a small solid papilla 2 to 3 µm in length. The antapical part with a subsquare and rounded outline bears a very discreet antapical protuberance less than 1 µm in size. The endophragm and periphragm are connected by filiform projections in the apical and antapical region. The paratabulation is vaguely indicated: 6", ?6c, 5'", 1"", xs. The archaeopyle is precingulate type P (3") with a free or attached operculum.
Description: The cyst is bicavate; the endocyst is ovoid to subspheroidal with a small apical protrusion (1 to 2 µm in length); The pericyst is elongated longitudinally with a broad apical pericoel and an antapical pericoel, of equal size (30 to 40 µm in length), which have slight constrictions near the anterior and posterior ends of the endocyst. The endophragm is quite thick (around 2 pm) and smooth. The periphragm is microreticulate with a generally fibrous appearance, and bears parasutural membranous ridges (up to 14 µm in height) higher at their junctions, particularly on the paracingulum, and often intercalated with hollow vesicles (2 to 20 µm in diameter). ) larger and more numerous especially on the paracingulum. The latter is wide (6 to 14 µm), laevotatory and marked by the alignment in a single row of vesicles and/or sometimes possible spines (6 to 14 µm) that are weakly developed. The parasulcus may have 2 to 3 short spines. Forms that lack spines probably show early beginnings of gonal processes indicated by an increase in the height of the ridges at the points of their gonal junctions. This slight variability is considered intraspecific because all intermediate forms are present in the material studied.
Dimensions: Holotype: maximum endocyst diameter: 70 µm; pericyst. length: 130 µm, width: 80 µm. Variations: endocyst diameter: 50 - 70 µm; pericyst, length: 80 - 130 µm, width: 70 - 80 µm. Number of specimens measured: 8.
Material: 12 copies.
Comparison: This species is very comparable to Triblastula fibrata in the unpublished work of WILSON (1974), this author mentioned in his remark p. 165 that he found rare specimens with weakly developed processes in the paracingulate region and he considered them as intermediate forms between T. fibrata and T. utinensis O. WETZEL (1933b) emend. SARJEANT (1985b); in the present work we group forms with and without processes into a single species. With the exception of its possible processes, T. wilsonii sp. nov. is distinguished from T. utinensis (Pl. 9, fig. 1,2) by its rounded pericyst in the apical and antapical region and especially by its dome-shaped apical part, by its shorter apical horn surmounted by a small papilla, by the presence of numerous vesicles mainly marking the paracingulum and also by the absence of a true antapical horn. T. utinensis has a pericyst of subpolygonal outline with an apical part almost in the form of a minaret (SARJEANT, 1985b: p. 139) extended by a much longer apical horn, and an antapical part provided with a more pronounced antapical horn; the processes are more numerous and more developed both on the paracingulum and elsewhere.
Stratigraphic distribution: Turnhout: -850.72 to -836.95 m, late Maastrichtian inf. - early upper Maastrichtian. In WILSO N (1974), Maastrichtian inf. (occidentalis/lanceolata Zone), Hvidskud. Klint, Denmark.