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Wanaea talea
From Fensome et al., 2019:
Wanaea talea Riding and Helby, 2001b, p.45,47,49, figs.7C,8A–I.
Holotype: Riding and Helby, 2001b, figs.7C,8I.
Age: middle Oxfordian.
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Original description (Riding & Helby, 2001b):
Wanaea talae sp. nov. (Figs 7C, 8A-I)
1958 Wanaea spectabilis (Deflandre & Cookson 1955); Cookson & Eisenack, p. 57, pl. 9
1981 Wanaea spectabilis (Deflandre & Cookson 1955) Cookson & Eisenack 1958; Fensome, fig. 3
1987 Wanaea spectabilis (Deflandre & Cookson 1955) Cookson & Eisenack 1958; Helby et al., fig. 18A.
Previous Australian usage:
Wanaea spectabilis – Ott (1970, pl. 8, figs 19, 20)
Wanaea spectabilis – Parker (1986, pl. 41, fig 9)
Wanaea spectabilis – Helby.
Description. An acavate, intermediate to large species of Wanaea with a conical hypocyst and with or without a short, distally blunt and rounded antapical horn which may be slightly inclined. The epicyst is essentially flat. Autophragm smooth. Paratabulation is absent on the hypocyst, apart from a prominent posterior paracingular flange; although accessory Archeopyle sutures are not uncommon on the epicyst. The paracingular flange is 5-11 µm wide, equatorial in position and interrupt at the indented parasulcus. The flange comprises a short (1-4 µm) proximal zone, which is entirely to rarely irregularly vacuolated. This is surmounted by simple, slender (1-2 µm wide), solid, processes which are linked distally by a continuous trabeculum. The processes vary from 3-9 µm in length, however, most are between 5 and 7 µm. The trabeculum is c. 1 µm in width, parallel sides and imparts a smooth distal margin of the flange. The processes are inserted densely and regularly are approximately every 1 to 2 µm along the flange. The flange is not always perfectly regular and small, irregular areas where the processes appear to coalesce may occur. In these areas, the flange is usually solid or sparsely and irregularly vacuolated. Rarely, some processes bifurcate distally or are connected medially. Principal Archeopyle suture generally smooth, located immediately anterior of the anterior paracingular parasuture. The operculum is frequently attached ventrally.
Dimensions (µm, n = 28): Min.(Mean)Max.
Length of hypocyst: 49 (62) 73
Width of cyst (incl. paracingular flange): 90 (107) 134
Width of cyst (excl. paracingular flange): 73 (92) 115
Width of paracingular flange: 5 (7) 11
Length of processes in paracingular flange: 3 (5) 9
Length of antapical horn: 5 (9) 18
The epicyst of this species is profoundly flattened and no epicyst were observed in lateral view, therefor the length of the entire cyst is approximately equal to the length of the hypocyst. It proved difficult to accurately and consistently measure the antapical horn because a distinct protuberance on the hypocyst is not always developed.
The measured specimens are from sidewall cores in Circinus-1 ST1 well at 3517.50m, Crux-1 well at 3266.60m and Buang-1 well at 3518.50m and sample 40, ditch cuttings between 4285.54m and 4288.59m from Island Exploration Company Omati-1 well, south-east Papua New Guinea (Cookson & Eisenack, 1958, figs. 1, 2).
Comments: The most characteristic feature of this species is the trabeculum which forms a distinct, regular, outer rim t the paracingular flange (Figs 7C, 8). The epicyst of Wanaea talea is flat, which is consistent with other species of Wanaea with prominent posterior paracingular flanges. Typically, the hypocyst is relatively low and wide, has subtriangular outline, typically with no clearly differentiated antapical horn. The postcingular flange is extremely characteristic, having a narrow, largely solid proximal zone surmounted by prominent parallel to subparallel, simple processes which are distally trabeculate. The proximal zone of the flange is normally 2-3 µm across, it is rarely reduced to 1 µm Restricted, irregularly vacuolare areas may occur in the flange. Rarely, some processes are distally bifurcate or medial connections are developed.
Comparison: Wanaea talea is similar to other members of the genus with prominent posterior paracingular flanges. Of these, it is most similar to Wanaea spectabilis, with which it intergrades. However, the flange of W. talea is much more simple than that of W. spectabilis, having a short, entire proximal zone which is surmounted by simple processes which are distally connected at a single trabeculate strand. The flange of W. spectabilis is much wider, has longer, more complex processes and a thin outer reticulate to vacuolated rim. The posterior paracingular flange of W. clathrate resembles that of W. talea in having a smooth distal margin. However, the flange f W. chalthrata can be extremely wide and is vacuolated, comprising elements which form a reltively regular, complex pattern (Cookson & Eisenack 1958, pl. 9, fig 7, 8). Wanaea digitate g=has a two-layered posteror paracingular flange, which lacks a distal trabeculum. The inner zone is fenestate to vacuolated and is surmounted by spines (Cookson & Eisenack, 1958, pl. 9, figs 4, 5; Woollam, 1982, fig. 1Bi). Wanaea talea is also similar to Wanaea thysanota and W. fimbriate. The resemblance is closest in W. thysanota, which has simple, solid distal processes which are occasionally connected. However, the posterior paracingular flanges of both these species are irregular, and there is no consistent distal trabeculum (Woollam, 1982, figs 1Bii,, 1Biv.
Derivation of name: From the Latin talea, meaning slender staff, rod, or stick and referring to the distinctive, simple, rod-like trabeculum at the distal side of the posterior paracingular flange.
Holotype and type locality: Figures 7C, 8I, Museum of Victoria specimen P.17297, sample 40, ditch cuttings between 4285.54m and 4288.59m from Island Exploration Company Omati-1 well, south-east Papua New Guinea (Cookson & Eisenack, 1958, figs 1, 2).
Stratigraphical distribution. Wanaea talea is confined to the Oxfordian, upper part of the Wanaea spectabilis Zone (subzones 6cib-6cia) (Figs 11, 12; Foster, this volume; Helby & Partridge, in prep.) It is an inconsistent, relatively rare, component of the lower subzone (6cib), however, it may occur prominently in the upper part of the zone (subzone 6cia).
Wanaea talea Riding and Helby, 2001b, p.45,47,49, figs.7C,8A–I.
Holotype: Riding and Helby, 2001b, figs.7C,8I.
Age: middle Oxfordian.
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Original description (Riding & Helby, 2001b):
Wanaea talae sp. nov. (Figs 7C, 8A-I)
1958 Wanaea spectabilis (Deflandre & Cookson 1955); Cookson & Eisenack, p. 57, pl. 9
1981 Wanaea spectabilis (Deflandre & Cookson 1955) Cookson & Eisenack 1958; Fensome, fig. 3
1987 Wanaea spectabilis (Deflandre & Cookson 1955) Cookson & Eisenack 1958; Helby et al., fig. 18A.
Previous Australian usage:
Wanaea spectabilis – Ott (1970, pl. 8, figs 19, 20)
Wanaea spectabilis – Parker (1986, pl. 41, fig 9)
Wanaea spectabilis – Helby.
Description. An acavate, intermediate to large species of Wanaea with a conical hypocyst and with or without a short, distally blunt and rounded antapical horn which may be slightly inclined. The epicyst is essentially flat. Autophragm smooth. Paratabulation is absent on the hypocyst, apart from a prominent posterior paracingular flange; although accessory Archeopyle sutures are not uncommon on the epicyst. The paracingular flange is 5-11 µm wide, equatorial in position and interrupt at the indented parasulcus. The flange comprises a short (1-4 µm) proximal zone, which is entirely to rarely irregularly vacuolated. This is surmounted by simple, slender (1-2 µm wide), solid, processes which are linked distally by a continuous trabeculum. The processes vary from 3-9 µm in length, however, most are between 5 and 7 µm. The trabeculum is c. 1 µm in width, parallel sides and imparts a smooth distal margin of the flange. The processes are inserted densely and regularly are approximately every 1 to 2 µm along the flange. The flange is not always perfectly regular and small, irregular areas where the processes appear to coalesce may occur. In these areas, the flange is usually solid or sparsely and irregularly vacuolated. Rarely, some processes bifurcate distally or are connected medially. Principal Archeopyle suture generally smooth, located immediately anterior of the anterior paracingular parasuture. The operculum is frequently attached ventrally.
Dimensions (µm, n = 28): Min.(Mean)Max.
Length of hypocyst: 49 (62) 73
Width of cyst (incl. paracingular flange): 90 (107) 134
Width of cyst (excl. paracingular flange): 73 (92) 115
Width of paracingular flange: 5 (7) 11
Length of processes in paracingular flange: 3 (5) 9
Length of antapical horn: 5 (9) 18
The epicyst of this species is profoundly flattened and no epicyst were observed in lateral view, therefor the length of the entire cyst is approximately equal to the length of the hypocyst. It proved difficult to accurately and consistently measure the antapical horn because a distinct protuberance on the hypocyst is not always developed.
The measured specimens are from sidewall cores in Circinus-1 ST1 well at 3517.50m, Crux-1 well at 3266.60m and Buang-1 well at 3518.50m and sample 40, ditch cuttings between 4285.54m and 4288.59m from Island Exploration Company Omati-1 well, south-east Papua New Guinea (Cookson & Eisenack, 1958, figs. 1, 2).
Comments: The most characteristic feature of this species is the trabeculum which forms a distinct, regular, outer rim t the paracingular flange (Figs 7C, 8). The epicyst of Wanaea talea is flat, which is consistent with other species of Wanaea with prominent posterior paracingular flanges. Typically, the hypocyst is relatively low and wide, has subtriangular outline, typically with no clearly differentiated antapical horn. The postcingular flange is extremely characteristic, having a narrow, largely solid proximal zone surmounted by prominent parallel to subparallel, simple processes which are distally trabeculate. The proximal zone of the flange is normally 2-3 µm across, it is rarely reduced to 1 µm Restricted, irregularly vacuolare areas may occur in the flange. Rarely, some processes are distally bifurcate or medial connections are developed.
Comparison: Wanaea talea is similar to other members of the genus with prominent posterior paracingular flanges. Of these, it is most similar to Wanaea spectabilis, with which it intergrades. However, the flange of W. talea is much more simple than that of W. spectabilis, having a short, entire proximal zone which is surmounted by simple processes which are distally connected at a single trabeculate strand. The flange of W. spectabilis is much wider, has longer, more complex processes and a thin outer reticulate to vacuolated rim. The posterior paracingular flange of W. clathrate resembles that of W. talea in having a smooth distal margin. However, the flange f W. chalthrata can be extremely wide and is vacuolated, comprising elements which form a reltively regular, complex pattern (Cookson & Eisenack 1958, pl. 9, fig 7, 8). Wanaea digitate g=has a two-layered posteror paracingular flange, which lacks a distal trabeculum. The inner zone is fenestate to vacuolated and is surmounted by spines (Cookson & Eisenack, 1958, pl. 9, figs 4, 5; Woollam, 1982, fig. 1Bi). Wanaea talea is also similar to Wanaea thysanota and W. fimbriate. The resemblance is closest in W. thysanota, which has simple, solid distal processes which are occasionally connected. However, the posterior paracingular flanges of both these species are irregular, and there is no consistent distal trabeculum (Woollam, 1982, figs 1Bii,, 1Biv.
Derivation of name: From the Latin talea, meaning slender staff, rod, or stick and referring to the distinctive, simple, rod-like trabeculum at the distal side of the posterior paracingular flange.
Holotype and type locality: Figures 7C, 8I, Museum of Victoria specimen P.17297, sample 40, ditch cuttings between 4285.54m and 4288.59m from Island Exploration Company Omati-1 well, south-east Papua New Guinea (Cookson & Eisenack, 1958, figs 1, 2).
Stratigraphical distribution. Wanaea talea is confined to the Oxfordian, upper part of the Wanaea spectabilis Zone (subzones 6cib-6cia) (Figs 11, 12; Foster, this volume; Helby & Partridge, in prep.) It is an inconsistent, relatively rare, component of the lower subzone (6cib), however, it may occur prominently in the upper part of the zone (subzone 6cia).