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Voodooia tabulata
Voodooia tabulata Riding and Helby, 2001d, p.95,97, figs.17A–B,18A–O.
Taxonomic junior synonyms: Samsonia tabulata and Broomea tabulata (both names not validly published), both according to Riding and Helby (2001d, p.95).
Holotype: Riding and Helby, 2001d, fig.18M.
Age: early late Callovian.
Original description (Riding & Helby, 2001d):
Voodooia tabulata sp. nov. (Figs. 17A-B, 18A-O)
1996 Pareodinia spp.; Burger, pl. 8, figs S, T.
Previous Austtralian usage
Broomea tabulate – Ott (1970, pl. 9, figs 4-6)
Imbatodinium sp. – Lister/Burmah (BOC).
M.P. 707 – Helby
Samsonia tabulate – Morgan.
Description. A species of Voodooia which is not primarily dorsoventrally compressed and had microgranulate to occasionally microscabrate autophragm. The widest part of the cyst is at, or anterior of the prominent paracingulum. Apart from the tapering apical horn, the narrowest part of the cyst is posterior to the paracingulum, where a distinct ‘waist’ is developed close to the level of the antapical margin of the 4’’’paraplate. The dorsal side of the cyst is frequently slightly inflated. The three horns are rounded distally and are of variable length, especially the paired antapical horns. A small capitate structure may be developed on the distal part of the apical horn and rarely, small, solid spinules are developed on the antapical horns. The apical horn is generally distinct, and the rest of the epicyst is cone-shaped. Paratabulation is indicated by low, smooth parasutural ridges, which are most prominent at, and adjacent to, the paracinulum. The parasulcus is indented. Generally the paratabulation is fully indicated, however the parasutural ridges may be suppressed, especially in the apical and antapical regional.
Dimensions (µm, n=35): Min.(Mean)Max.
Length of cyst body incl. horns: 84 (105) 136
Length h of cyst body excl. horns: 52 (63) 80
Length of epicyst incl. apical horn: 53 (67) 94
Length of hypocyst incl. antapical horns: 21 (32) 43
Length (height) of paracingulum: 5 (8) 10
Width of cyst body: 25 (36) 44
Length of apical horn: 17 (28) 45
Length of antapical horns: 4 (16) 30
The specimens measured are from a conventional core sample at 3221.47m in Layang-1 well and from sidewall core samples in Challis-11 ST1 well at 1552.50m, Challis-11 ST2 well at 1842.00m and Montebello-1 well at 2575.00m.
Comments: Voodooia tabulate is a distinctive, elongate species. The precingular paraplates, in particular, are extremely long. However, the degree of elongation is extremely variable. The species appears o be either slightly squat in outline or markedly slender and elongate. Most specimens are large in size , but a minority are intermediate. In lateral view, this species is commonly asymmetrical; this is caused by the inflation of the dorsal side. This feature can often be a useful oriental criterion. Note that the average length of the hypocyst, including the antapical horns, is over half the length of the epicyst including the apical horn. Many specimens were observed in oblique lateral views, indicating that this species is not primarily dorsoventrally compressed. The species is often damages presumably mechanically, and it seems to split along parasutures. Dark, subspherical accumulation bodies are commonly present within the cyst. Some definite disruption of the anterior intercalary paraplate series was noted, which is interpreted as being related to archeopyle formation. The precise paraplate equivalence and whether the opercular piece(s) are adnate or free, however, is not clear. Some specimens do not appear to exhibit an excystement aperture.
Derivation of name: from the fact that this cyst is fully paratabulate
Holotype and type locality: Figure 18M, CPC 35484, Challis-11 ST1 well, sidewall core sample at 1552.50m
Stratigrapical distribution: Voodooia tabulate occurs in the lower part of the late Callovian Rigaudella aemua Zone (7ai) in the Timor Sea region (Foster, this volume; Helby & Partridge, in prep.). The speices is confined to subzones 7aiibia-7aiia in the Bayu-Undan Gas Field
Taxonomic junior synonyms: Samsonia tabulata and Broomea tabulata (both names not validly published), both according to Riding and Helby (2001d, p.95).
Holotype: Riding and Helby, 2001d, fig.18M.
Age: early late Callovian.
Original description (Riding & Helby, 2001d):
Voodooia tabulata sp. nov. (Figs. 17A-B, 18A-O)
1996 Pareodinia spp.; Burger, pl. 8, figs S, T.
Previous Austtralian usage
Broomea tabulate – Ott (1970, pl. 9, figs 4-6)
Imbatodinium sp. – Lister/Burmah (BOC).
M.P. 707 – Helby
Samsonia tabulate – Morgan.
Description. A species of Voodooia which is not primarily dorsoventrally compressed and had microgranulate to occasionally microscabrate autophragm. The widest part of the cyst is at, or anterior of the prominent paracingulum. Apart from the tapering apical horn, the narrowest part of the cyst is posterior to the paracingulum, where a distinct ‘waist’ is developed close to the level of the antapical margin of the 4’’’paraplate. The dorsal side of the cyst is frequently slightly inflated. The three horns are rounded distally and are of variable length, especially the paired antapical horns. A small capitate structure may be developed on the distal part of the apical horn and rarely, small, solid spinules are developed on the antapical horns. The apical horn is generally distinct, and the rest of the epicyst is cone-shaped. Paratabulation is indicated by low, smooth parasutural ridges, which are most prominent at, and adjacent to, the paracinulum. The parasulcus is indented. Generally the paratabulation is fully indicated, however the parasutural ridges may be suppressed, especially in the apical and antapical regional.
Dimensions (µm, n=35): Min.(Mean)Max.
Length of cyst body incl. horns: 84 (105) 136
Length h of cyst body excl. horns: 52 (63) 80
Length of epicyst incl. apical horn: 53 (67) 94
Length of hypocyst incl. antapical horns: 21 (32) 43
Length (height) of paracingulum: 5 (8) 10
Width of cyst body: 25 (36) 44
Length of apical horn: 17 (28) 45
Length of antapical horns: 4 (16) 30
The specimens measured are from a conventional core sample at 3221.47m in Layang-1 well and from sidewall core samples in Challis-11 ST1 well at 1552.50m, Challis-11 ST2 well at 1842.00m and Montebello-1 well at 2575.00m.
Comments: Voodooia tabulate is a distinctive, elongate species. The precingular paraplates, in particular, are extremely long. However, the degree of elongation is extremely variable. The species appears o be either slightly squat in outline or markedly slender and elongate. Most specimens are large in size , but a minority are intermediate. In lateral view, this species is commonly asymmetrical; this is caused by the inflation of the dorsal side. This feature can often be a useful oriental criterion. Note that the average length of the hypocyst, including the antapical horns, is over half the length of the epicyst including the apical horn. Many specimens were observed in oblique lateral views, indicating that this species is not primarily dorsoventrally compressed. The species is often damages presumably mechanically, and it seems to split along parasutures. Dark, subspherical accumulation bodies are commonly present within the cyst. Some definite disruption of the anterior intercalary paraplate series was noted, which is interpreted as being related to archeopyle formation. The precise paraplate equivalence and whether the opercular piece(s) are adnate or free, however, is not clear. Some specimens do not appear to exhibit an excystement aperture.
Derivation of name: from the fact that this cyst is fully paratabulate
Holotype and type locality: Figure 18M, CPC 35484, Challis-11 ST1 well, sidewall core sample at 1552.50m
Stratigrapical distribution: Voodooia tabulate occurs in the lower part of the late Callovian Rigaudella aemua Zone (7ai) in the Timor Sea region (Foster, this volume; Helby & Partridge, in prep.). The speices is confined to subzones 7aiibia-7aiia in the Bayu-Undan Gas Field