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Tringadinium bjaerkei
Tringadinium bjaerkei Riding and Helby, 2001e, p.128,130–131, figs.10A–T,11A–T.
Taxonomic junior synonym: Bulbosia tithonica (name not validly published), according to Riding and Helby (2001e, p.128).
Holotype: Riding and Helby, 2001e, figs.10Q–S.
Age: Callovian–Berriasian.
Original description (Riding & Helby, 2001e):
Tringadinium bjaerkei sp.nov. (Figs 10A-T, 11A-T)
1988 Gen. et sp. Nov. B (M.P.36) ; Helby et al., fig 15L
Previous Australian usage
Bulbosia tithonica – Ott (1970, pl. 7, figs 10, 11)
Gen et ap. Indet. A – Parker, 1986, p. 191, pl. 44, fig. 3)
M.P. 36 – Helby
Description: A species of Tringadinium which is rounded subpolygonal in outline, and with a pronounced paracigular constriction. The hypocyst is significantly larger tin length and width . Autophrragm extremely variable; it may be smooth, microreticulate, or surmounted by low relief ornamentation. The microreticulation, where developed, is normally sparse and the fenestrae are irregularly distributed; the fenestrae are 0.5 to 1.0 µm in diameter. Where present, the positive ornamentation varies in height and density, and it is possible for individual specimens to exhibit more than one ornament type. Individual elements of the ornamentation normally are between 0.5 and 1.0 µm, although rarely they may attain up to 2 µm in height. The autophragm may be scabrate, granulate or rarely, tuberculate and is extended into prominent intratabular rounded inflations or protuberances in the apical, precingular, postcingular and antapical paraplate series. These protuberances are usually wider and higher on the hypocyst than on the epicyst and are distally flat to rounded. The inflations on the apical paraplate series are extremely low in relief. Each protuberance normally has a subcircular to subquadrangular ridge or rim in a distal position. The rims are low and may be surmounted by low relief ornamentation, typically denticles, tubercles or pila up to 1 µm long. Some coalescence f this ornament may occur, giving rise to continuous subcircular ridges. Generally the interiors of the rims/ridges exhibit relatively dense intratabular ornament such as scabrae, granules and tubercules. The hypocyst may be symmetrical due to the differing sizes of the intratabular inflation on the antapical paraplates. This species is slightly primarily flattened dorsoventrally and the wide, midventral parasulcus is slightly indented.
Dimensions (µm, n=26, including ornament and/or protuberances where appropriate): Min.(Mean)Max.
Length of cyst, incl. operculum: 25 (33) 41
Length of loistocyst: 23 (32) 40
Length of epicyst: 6 (10) 18
Length of cyst at parcingulum: 3 (6) 10
Length of hypocyst: 11 (17) 25
Maximum width of epicyst: 15 (23) 34
Width of cyst at paracingulum: 12 (20) 32
Maximum width of hypocyst: 21 (28) 38
Maximum height of protuberance: 3 (5) 9
The measure specimens are from sidewall cores from Arunta-1 well at 1805.00m, 1919.00m and 2135.00m; Challis-11 ST-1 well at 1552.50m; Sandpiper-1 well at 658.38m; Serrurier-1 well at 1440.00m; Taltarni-1 well at 2950.00m; ditch cuttings from Peak-1 well from between 1493.54m and 1496.59m and Tithonian outcrop samples 81FH05 and 81FH11 from the Lelinta Formation (Fageo Group) Misool, eastern Indonesia.
Tringadinium bjaerkei is variable in size. Specimens from the W. spectabilis Zone of offshore north-western Australia are significantly smaller, and have more prominent ornamentation, than those from the Tithonian of Australia and Misool, Indonesia. 26 specimens from W. spectabilis Zone of offshore northwestern Australia gave the following data:
Dimensions, (µm, n=26): Min.(Mean)Max.
Length of cyst, incl. operculum: 25 (30) 33
Length of loistocyst: 23 (28) 35
Length of epicyst: 6 (9) 14
Length of cyst at parcingulum: 4 (6) 8
Length of hypocyst: 11 (15) 20
Maximum width of epicyst: 16 (20) 23
Width of cyst at paracingulum: 12 (17) 22
Maximum width of hypocyst: 21 (25) 30
Maximum height of protuberance: 3 (4.5) 7
By contrast, 36 specimens from the Tithonian of offshore north-western Australia and Missol, eastern Indonesia, gave the following size ranges:
Dimensions, (µm, n=36): Min.(Mean)Max.
Length of cyst, incl. operculum: 31 (36) 41
Length of loistocyst: 29 (34) 40
Length of epicyst: 7 (11) 18
Length of cyst at parcingulum: 3 (6) 10
Length of hypocyst: 15 (19) 25
Maximum width of epicyst: 18 (24) 34
Width of cyst at paracingulum: 14 (22) 32
Maximum width of hypocyst: 25 (31) 38
Maximum height of protuberance: 3 (5) 9
The sizes of the Tithonian material are consistently significantly greater than those of the Oxfordian (W. spectabilis Zone) specimens (see above). The most marked average size differences are in the lengths of the entire cyst, the length of the loistocyst and the width of the hypocyst. The size differences observed between the Oxfordian and Tithonian of north-western Australia and Indonesia may represent a potential morphostratigraphical lineage (Monteil, 1990; 1991). Furthermore, the older, Oxfordian material tends to have a granulate autophragm. The Tithonian specimens, by contrast, tend to have smooth autophragms outside the intratabular protuberances. Despite these differences, all the specimens are considered unequivocally to belong to Tringadinium bjaerkei because of significant overlap between the two morphotypes.
Comments: Tringadinium bjaerkei is rounded subpolygonal in outline. Frequently it is subhexagonal, the shape being distorted by prominent intratabular protuberances. The constriction at the apically offset paracingulum is also significantly variable in depth. The hypocyst is relatively large in comparsison to the paracingular area and the epicyst. The species also exhibits great variability in the nature and distribution or ornamentation. Typically, the interiors of the distal rims on each intratabular protuberance contain low relief ornamentation. This feature is similar to the penitabular/intratabular ornamental distribution in T. comptum sp. nov. However, in some Tithonian specimens, nontabular scarbae, granules and tubercules are present outside the intratbaular areas. These are normally significantly less dense than the intratabular ornamentation. Most Oxfordian specimens exhibit a uniform density of ornamentation over the entire cyst. Some may be smooth and/or irregularly microreticulate outside the intrtabular protuberances. The majority of the ornamentation lies inside the subcircular to subquadrangular distal rims on the intratabular protuberances. These rims or ridges are normally surmounted by low relief ornamentation. Rarely they are absent, their positions indicated only by vague rings of intratabular granules. The two antapical protuberances may be equal in size; however, frequently one is significantly larger than the other.
Comparison: Tringadinium bjaerkei differs from T. comptum sp. nov. in the consistent occurrence of prominent intratabular protuberances/inflations. The intratabular features, together with the size and shape, make T. bjaerkei significantly similar in appearance to the Early-Mid Jurassic taxon Susadinium scrofoides, and the other members of the Parvocysta suite (Riding, 1984) have a different paratabulation pattern and single paraplate anterior intercalary, type I, archeopyles. Susadinium scrofoides has five apical, three anterior intercalary, seven precingular, severn paracingular and five postcingular paraplates (Bjaerke, 1980); Evitt, 1985; Below, 1987a). the involvement of the apical paraplates in the Archeopyle and the intratabular protuberances make Susadinium? Australis Riding & Helby (this volume) similar in overall appearance to T. bjaerkei. However, the paratabulation pattern of S? australis conforms to that of Susadinium and S? australis lacks the smaller ornamental feature which are typical of T. bjaerkei. Furthermore, S? australis appears to have a combination (apical and anterior intercalary) archeopyle.
Derivation of name: In honour of Dr. Tor Bjaerke.
Holotype and type locality: Figures 10Q-S, CPC 35578, Sandpiper-1 well, sidewall core sample at 658.38m
Stratigrapical distribution: Tringadinium bjaerkei ranges from the Callovian, lower Rigeudella aemula Zone (7aiibi) to the Tithonian-Berriadian, Pseudoceratium iehiense Zone (4ci) on the North West shelf of Australia (Foster, this volume; Helby and Partridge, in prep.). it has also been recorded from the Tithonian Lelinta Formation (Fageo Group) of Misool, eastern Indonesia (Helby & Hasibuan, 1988). IN the New Zealand, it is recorded from the Kimmeridgian Waikutakuta Siltstone to the Tithonian Puti Siltstone (Helby et al., 1988).
Taxonomic junior synonym: Bulbosia tithonica (name not validly published), according to Riding and Helby (2001e, p.128).
Holotype: Riding and Helby, 2001e, figs.10Q–S.
Age: Callovian–Berriasian.
Original description (Riding & Helby, 2001e):
Tringadinium bjaerkei sp.nov. (Figs 10A-T, 11A-T)
1988 Gen. et sp. Nov. B (M.P.36) ; Helby et al., fig 15L
Previous Australian usage
Bulbosia tithonica – Ott (1970, pl. 7, figs 10, 11)
Gen et ap. Indet. A – Parker, 1986, p. 191, pl. 44, fig. 3)
M.P. 36 – Helby
Description: A species of Tringadinium which is rounded subpolygonal in outline, and with a pronounced paracigular constriction. The hypocyst is significantly larger tin length and width . Autophrragm extremely variable; it may be smooth, microreticulate, or surmounted by low relief ornamentation. The microreticulation, where developed, is normally sparse and the fenestrae are irregularly distributed; the fenestrae are 0.5 to 1.0 µm in diameter. Where present, the positive ornamentation varies in height and density, and it is possible for individual specimens to exhibit more than one ornament type. Individual elements of the ornamentation normally are between 0.5 and 1.0 µm, although rarely they may attain up to 2 µm in height. The autophragm may be scabrate, granulate or rarely, tuberculate and is extended into prominent intratabular rounded inflations or protuberances in the apical, precingular, postcingular and antapical paraplate series. These protuberances are usually wider and higher on the hypocyst than on the epicyst and are distally flat to rounded. The inflations on the apical paraplate series are extremely low in relief. Each protuberance normally has a subcircular to subquadrangular ridge or rim in a distal position. The rims are low and may be surmounted by low relief ornamentation, typically denticles, tubercles or pila up to 1 µm long. Some coalescence f this ornament may occur, giving rise to continuous subcircular ridges. Generally the interiors of the rims/ridges exhibit relatively dense intratabular ornament such as scabrae, granules and tubercules. The hypocyst may be symmetrical due to the differing sizes of the intratabular inflation on the antapical paraplates. This species is slightly primarily flattened dorsoventrally and the wide, midventral parasulcus is slightly indented.
Dimensions (µm, n=26, including ornament and/or protuberances where appropriate): Min.(Mean)Max.
Length of cyst, incl. operculum: 25 (33) 41
Length of loistocyst: 23 (32) 40
Length of epicyst: 6 (10) 18
Length of cyst at parcingulum: 3 (6) 10
Length of hypocyst: 11 (17) 25
Maximum width of epicyst: 15 (23) 34
Width of cyst at paracingulum: 12 (20) 32
Maximum width of hypocyst: 21 (28) 38
Maximum height of protuberance: 3 (5) 9
The measure specimens are from sidewall cores from Arunta-1 well at 1805.00m, 1919.00m and 2135.00m; Challis-11 ST-1 well at 1552.50m; Sandpiper-1 well at 658.38m; Serrurier-1 well at 1440.00m; Taltarni-1 well at 2950.00m; ditch cuttings from Peak-1 well from between 1493.54m and 1496.59m and Tithonian outcrop samples 81FH05 and 81FH11 from the Lelinta Formation (Fageo Group) Misool, eastern Indonesia.
Tringadinium bjaerkei is variable in size. Specimens from the W. spectabilis Zone of offshore north-western Australia are significantly smaller, and have more prominent ornamentation, than those from the Tithonian of Australia and Misool, Indonesia. 26 specimens from W. spectabilis Zone of offshore northwestern Australia gave the following data:
Dimensions, (µm, n=26): Min.(Mean)Max.
Length of cyst, incl. operculum: 25 (30) 33
Length of loistocyst: 23 (28) 35
Length of epicyst: 6 (9) 14
Length of cyst at parcingulum: 4 (6) 8
Length of hypocyst: 11 (15) 20
Maximum width of epicyst: 16 (20) 23
Width of cyst at paracingulum: 12 (17) 22
Maximum width of hypocyst: 21 (25) 30
Maximum height of protuberance: 3 (4.5) 7
By contrast, 36 specimens from the Tithonian of offshore north-western Australia and Missol, eastern Indonesia, gave the following size ranges:
Dimensions, (µm, n=36): Min.(Mean)Max.
Length of cyst, incl. operculum: 31 (36) 41
Length of loistocyst: 29 (34) 40
Length of epicyst: 7 (11) 18
Length of cyst at parcingulum: 3 (6) 10
Length of hypocyst: 15 (19) 25
Maximum width of epicyst: 18 (24) 34
Width of cyst at paracingulum: 14 (22) 32
Maximum width of hypocyst: 25 (31) 38
Maximum height of protuberance: 3 (5) 9
The sizes of the Tithonian material are consistently significantly greater than those of the Oxfordian (W. spectabilis Zone) specimens (see above). The most marked average size differences are in the lengths of the entire cyst, the length of the loistocyst and the width of the hypocyst. The size differences observed between the Oxfordian and Tithonian of north-western Australia and Indonesia may represent a potential morphostratigraphical lineage (Monteil, 1990; 1991). Furthermore, the older, Oxfordian material tends to have a granulate autophragm. The Tithonian specimens, by contrast, tend to have smooth autophragms outside the intratabular protuberances. Despite these differences, all the specimens are considered unequivocally to belong to Tringadinium bjaerkei because of significant overlap between the two morphotypes.
Comments: Tringadinium bjaerkei is rounded subpolygonal in outline. Frequently it is subhexagonal, the shape being distorted by prominent intratabular protuberances. The constriction at the apically offset paracingulum is also significantly variable in depth. The hypocyst is relatively large in comparsison to the paracingular area and the epicyst. The species also exhibits great variability in the nature and distribution or ornamentation. Typically, the interiors of the distal rims on each intratabular protuberance contain low relief ornamentation. This feature is similar to the penitabular/intratabular ornamental distribution in T. comptum sp. nov. However, in some Tithonian specimens, nontabular scarbae, granules and tubercules are present outside the intratbaular areas. These are normally significantly less dense than the intratabular ornamentation. Most Oxfordian specimens exhibit a uniform density of ornamentation over the entire cyst. Some may be smooth and/or irregularly microreticulate outside the intrtabular protuberances. The majority of the ornamentation lies inside the subcircular to subquadrangular distal rims on the intratabular protuberances. These rims or ridges are normally surmounted by low relief ornamentation. Rarely they are absent, their positions indicated only by vague rings of intratabular granules. The two antapical protuberances may be equal in size; however, frequently one is significantly larger than the other.
Comparison: Tringadinium bjaerkei differs from T. comptum sp. nov. in the consistent occurrence of prominent intratabular protuberances/inflations. The intratabular features, together with the size and shape, make T. bjaerkei significantly similar in appearance to the Early-Mid Jurassic taxon Susadinium scrofoides, and the other members of the Parvocysta suite (Riding, 1984) have a different paratabulation pattern and single paraplate anterior intercalary, type I, archeopyles. Susadinium scrofoides has five apical, three anterior intercalary, seven precingular, severn paracingular and five postcingular paraplates (Bjaerke, 1980); Evitt, 1985; Below, 1987a). the involvement of the apical paraplates in the Archeopyle and the intratabular protuberances make Susadinium? Australis Riding & Helby (this volume) similar in overall appearance to T. bjaerkei. However, the paratabulation pattern of S? australis conforms to that of Susadinium and S? australis lacks the smaller ornamental feature which are typical of T. bjaerkei. Furthermore, S? australis appears to have a combination (apical and anterior intercalary) archeopyle.
Derivation of name: In honour of Dr. Tor Bjaerke.
Holotype and type locality: Figures 10Q-S, CPC 35578, Sandpiper-1 well, sidewall core sample at 658.38m
Stratigrapical distribution: Tringadinium bjaerkei ranges from the Callovian, lower Rigeudella aemula Zone (7aiibi) to the Tithonian-Berriadian, Pseudoceratium iehiense Zone (4ci) on the North West shelf of Australia (Foster, this volume; Helby and Partridge, in prep.). it has also been recorded from the Tithonian Lelinta Formation (Fageo Group) of Misool, eastern Indonesia (Helby & Hasibuan, 1988). IN the New Zealand, it is recorded from the Kimmeridgian Waikutakuta Siltstone to the Tithonian Puti Siltstone (Helby et al., 1988).