Back
Phallocysta elongata
Phallocysta elongata (Beju, 1971, p.289–290, pl.3, figs.7–10; text-figs.6A–E) Riding, 1994, p.16. Emendations: Feist-Burkhardt and Monteil, 1994, p.9, as Andreedinium elongatum; Riding, 1994, p.16, as Phallocysta elongata.
Holotype: Beju, 1971, pl.3, fig.7; text-fig.6A.
Originally Fromea (Appendix A), subsequently Fromea? (Appendix A), thirdly Wallodinium, fourthly Palaeostomocystis (Appendix A), fifthly Andreedinium, sixthly (and now) Phallocysta.
Nomenclatural junior synonym: Phallocysta minuta, which see for details.
Taxonomic senior synonym: Prismatocystis (now Wallodinium) cylindrica, according to Duxbury (1983, p.68) — however, Feist-Burkhardt and Monteil in Feist-Burkhardt (1990, p.615) retained Phallocysta (as Andreedinium) elongata.
Taxonomic junior synonym: Phallocysta subconica, according to Riding (1994, p.16). Age: Bajocian–Oxfordian.
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Phallocysta elongata (Beju, 1971) Riding, 1994, emend. Feist-Burkhardt and Monteil, 1994. According to Feist-Burkhardt and Monteil (1994), this species (as Andreedinium elongatum) differs from Phallocysta erregulensis in having the periphragm and endophragm closely appressed in the hypocyst, rather than there being hypopericoels. In P.elongata, the endocyst is restricted to the hypocyst. Emended description. Proximate, epicavate, with straight longitudinal axis. Pericyst elongate ovoidal, with tapered epicyst and a weak constriction in its anterior part at about the three-quarters cyst length; apex narrowly rounded or slightly pointed; antapex broadly rounded. Endocyst subspherical to ellipsoidal, occupying most of the hypocyst, closely appressed to the pericyst in the hypocystal region. Periphragm and endophragm psilate to finely punctate; periphragm sometimes faintly longitudinally striped. Periarcheopyle intercalary type 3Ia. Periopercular pieces posteriorly adnate to the precingular paraplates. Endoarcheopyle type indeterminate, frequently developed. Paratabulation expressed by archeopyle only. Paracingulum and parasulcus not indicated. Size: length of pericyst 42-56 µm, width 24-32 µm, length of endocyst 24-35 µm, width 24-32 µm.
--------------------------------------------------
Original diagnosis: Beju 1971, p. 289: Shell formed of two distinct parts: a subspherical or slightly elongated chamber prolonged by a subcylindrical or slightly conical nack, wide opened at its apical end. The transition from the chamber to the nack is gradual but always recognizable on the borders. Neck/chamber ratio 1/4 to 1/3. Shell wall relatively thin (0.5-1.5 microns), levigate to finely punctate. Opening wide, subcircular with smooth or slightly undulated margins.
Remarks: The presence of an equatorial cingulum could not be observed in any of the numerous specimens met with.This species differs from Fromea amphora Cookson and Eisenack 1958 by its neck.
Dimensions (on more than 250 specimens). Overall length: 46-70 µm; overall width: 24-36 µm.
Occurrence: Common in J2 zone, present in J3 zone (Craiova, Ciuresti, Poiana Mare, Oporelu, Plaveceni, Glavanesti, Aldesti, etc.).
--------------------------------------------------------------------------------------------------------------------------------------------------
Emended Diagnosis. Riding 1994, p. 16-17
Proximate, epicavate, small to intermediate (of Stover and Evitt, 1978) dinoflagellate cysts with an elongate, ovoidal ambitus. The pericyst is subconical, narrowing markedly in an apical direction; apical region subangular. Antapex rounded. Endocyst spherical to subspherical, antapically positioned; extends to the paracingular area. Periphragm and endophragm closely appressed, smooth to scabrate. Periphragm relatively thin; endophragm relatively thick. Periarcheopyle anterior intercalary, type 3I; periopercula free; this feature is the only manifestation of paratabulation.
Description. Riding 1994, p. 16-17
A smooth or occasionally scabrate species of Phallocysta. The pericyst is subconical to flask-shaped, becoming markedly constricted apically. Flask-shaped specimens exhibit a distinct area of narrowing within the epicyst anterior of the paracingular region (Plate 1, figures 1, 2,6-8). The apical part of the endocyst may occasionally be flattened. Both cyst layers are in close mutual contact. The periarcheopyle is anteriorintercalary, heperioperculum comprises all three anterior intercalary paraplates, which are free. Therefore, the periarcheopyle is relatively large (Plate l, figures 1-10). The paratabulation is expressed by the principal periarcheopyle suture only. The endo-archeopyle style has not been observed.
Dimensions (µm). 65 specimens measured.
Minimum Mean Maximum
Pericyst length 44.6 49.7 60.3
Peri- & endocyst width 25.4 29.2 38.4
Endocyst length 26.1 31.2 38.5
Remarks: Riding 1994, p. 16-17
Wallodinium cylindricum (Habib 1970) Duxbury 1983 emend. nov. (and Wallodinium sp. A), despite being subcylindrical and having apical peri- and endoarcheopyles, are similar in overall morphology to some specimens of Phallocysta elongata. This is the principal reason why the taxonomic confusion surrounding Wallodinium cylindricum and Phallocysta elongata has occurred. Using the type material of 'Fromea' elongata (Beju,1971) as an example, it is evident why the specimens in his pl. 3, fig. 7 (the holotype) and text-fig. 6A-E were interpreted as having apical periarcheopyles. The figured specimen pl. 3, fig. 8 of Beju (1971) has an intercalary periarcheopyle (see also Plate 1, figs. 1-13 herein). The phenomenon here is not periarcheopyle variability, but simply that poorly preserved specimens of Phallocysta elongata may appear to have apical periarcheopyles due to apical truncation caused by mechanical damage. The fact that this species has an anterior intercalary periarcheopyle (type 3I) was first mentioned by Feist-Burkhardt (1990, p. 615); this author also contended that the periopercula are adnate to the precingular paraplates. Study of well-preserved material from Britain confirms the periarcheopyle to be consistently intercalary. However, most of the specimens observed (and the type material) appear to have free opercula (see Plate 1, figures 1-12). Phallocysta? erregulensis (Filatoff 1975) Stover & Helby 1987 also resembles Phallocysta elongata. However, Phallocysta? erregulensis has a single paraplate peri- and endoarcheopyle. It typically has a broadly rounded apex, the pericyst may be trilobate and the endocyst may be roundedtriangular. Furthermore, Phallocysta? Erregulensis is generally epicavate but may be bicavate, circumcavate or cornucavate, Phallocysta elongata is consistently epicavate. The ambitus of Phallocysta? erregulensis is markedly variable and cornucavate forms may be laterally elongate; P. elongata invariably has an elongate pericyst. The endocyst of Phallocysta? erregulensis fills the entire hypocyst and extends into the epicyst. By contrast, Phallocysta elongata has a relatively small endocyst. The granulate morphotypes of Phallocysta elongata have low-relief, typically sparse ornamentation. The granulation, where present, of Phallocysta? erregulensis is relatively dense and is uniform and the endophragm may be spinate.
Stratigraphic and Geographic Distribution. Phallocysta elongata has been recorded from the uppermost Toarcian (D. Ievesquei Zone) to the lower Bajocian (W. Iaeviuscula Zone) (Lower-Middle Jurassic) of north- west Europe (Riding,1987; De Vains,1988; Prauss,1989; Feist-Burkhardt, 1990; Riding et al.,1991; Feist-Burkhardt and Wille, 1992, Colin et al., 1992; Riding and Thomas, 1992). Studies of independently dated material from northwest Europe indicate that the range top of this species is normally in the lowermost Bajocian (H. discites Zone) (Riding, 1987; Prauss, 1980). The report of the species from the base of the overlying S. ovalis Subzone of the W. laeviuscula Zone of Scotland by Riding et al. (1991, text-fig. A3) is based on a small number of specimens compared to relatively abundant material below. This may indicate that the S. ovalis Subzone material is reworked, a contention supported by the fact that this section was deposited in relatively high energy conditions. The original report from Romania(Beju,1971)was stated to be Bajocian-Bathonian to Callovian-Oxfordian (Middle-Upper Jurassic). The latter occurrences may represent local reworking. De Vains (1988, p. 464) also reported granulate Wallodinium spp. from the upper Toarcian (G. thouarsene Zone) of southern France. These forms, however, were not illustrated thus is is not clear if they are referable to Phallocysta elomgata. Granulate morphotypes (e.g. De Vains, 1988, p. 464; Riding et al. 1991, pl. 2, figs. 21-25; Plate 1, figure 12) tend to be confined to the upper Toarcian. Specimens from the AAlenian and lower Bajocian are consistently psilate.This distinction can be confidently used as an example of morphostratigraphy. Further study may allow a subspecific distinction to be made.
Holotype: Beju, 1971, pl.3, fig.7; text-fig.6A.
Originally Fromea (Appendix A), subsequently Fromea? (Appendix A), thirdly Wallodinium, fourthly Palaeostomocystis (Appendix A), fifthly Andreedinium, sixthly (and now) Phallocysta.
Nomenclatural junior synonym: Phallocysta minuta, which see for details.
Taxonomic senior synonym: Prismatocystis (now Wallodinium) cylindrica, according to Duxbury (1983, p.68) — however, Feist-Burkhardt and Monteil in Feist-Burkhardt (1990, p.615) retained Phallocysta (as Andreedinium) elongata.
Taxonomic junior synonym: Phallocysta subconica, according to Riding (1994, p.16). Age: Bajocian–Oxfordian.
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Phallocysta elongata (Beju, 1971) Riding, 1994, emend. Feist-Burkhardt and Monteil, 1994. According to Feist-Burkhardt and Monteil (1994), this species (as Andreedinium elongatum) differs from Phallocysta erregulensis in having the periphragm and endophragm closely appressed in the hypocyst, rather than there being hypopericoels. In P.elongata, the endocyst is restricted to the hypocyst. Emended description. Proximate, epicavate, with straight longitudinal axis. Pericyst elongate ovoidal, with tapered epicyst and a weak constriction in its anterior part at about the three-quarters cyst length; apex narrowly rounded or slightly pointed; antapex broadly rounded. Endocyst subspherical to ellipsoidal, occupying most of the hypocyst, closely appressed to the pericyst in the hypocystal region. Periphragm and endophragm psilate to finely punctate; periphragm sometimes faintly longitudinally striped. Periarcheopyle intercalary type 3Ia. Periopercular pieces posteriorly adnate to the precingular paraplates. Endoarcheopyle type indeterminate, frequently developed. Paratabulation expressed by archeopyle only. Paracingulum and parasulcus not indicated. Size: length of pericyst 42-56 µm, width 24-32 µm, length of endocyst 24-35 µm, width 24-32 µm.
--------------------------------------------------
Original diagnosis: Beju 1971, p. 289: Shell formed of two distinct parts: a subspherical or slightly elongated chamber prolonged by a subcylindrical or slightly conical nack, wide opened at its apical end. The transition from the chamber to the nack is gradual but always recognizable on the borders. Neck/chamber ratio 1/4 to 1/3. Shell wall relatively thin (0.5-1.5 microns), levigate to finely punctate. Opening wide, subcircular with smooth or slightly undulated margins.
Remarks: The presence of an equatorial cingulum could not be observed in any of the numerous specimens met with.This species differs from Fromea amphora Cookson and Eisenack 1958 by its neck.
Dimensions (on more than 250 specimens). Overall length: 46-70 µm; overall width: 24-36 µm.
Occurrence: Common in J2 zone, present in J3 zone (Craiova, Ciuresti, Poiana Mare, Oporelu, Plaveceni, Glavanesti, Aldesti, etc.).
--------------------------------------------------------------------------------------------------------------------------------------------------
Emended Diagnosis. Riding 1994, p. 16-17
Proximate, epicavate, small to intermediate (of Stover and Evitt, 1978) dinoflagellate cysts with an elongate, ovoidal ambitus. The pericyst is subconical, narrowing markedly in an apical direction; apical region subangular. Antapex rounded. Endocyst spherical to subspherical, antapically positioned; extends to the paracingular area. Periphragm and endophragm closely appressed, smooth to scabrate. Periphragm relatively thin; endophragm relatively thick. Periarcheopyle anterior intercalary, type 3I; periopercula free; this feature is the only manifestation of paratabulation.
Description. Riding 1994, p. 16-17
A smooth or occasionally scabrate species of Phallocysta. The pericyst is subconical to flask-shaped, becoming markedly constricted apically. Flask-shaped specimens exhibit a distinct area of narrowing within the epicyst anterior of the paracingular region (Plate 1, figures 1, 2,6-8). The apical part of the endocyst may occasionally be flattened. Both cyst layers are in close mutual contact. The periarcheopyle is anteriorintercalary, heperioperculum comprises all three anterior intercalary paraplates, which are free. Therefore, the periarcheopyle is relatively large (Plate l, figures 1-10). The paratabulation is expressed by the principal periarcheopyle suture only. The endo-archeopyle style has not been observed.
Dimensions (µm). 65 specimens measured.
Minimum Mean Maximum
Pericyst length 44.6 49.7 60.3
Peri- & endocyst width 25.4 29.2 38.4
Endocyst length 26.1 31.2 38.5
Remarks: Riding 1994, p. 16-17
Wallodinium cylindricum (Habib 1970) Duxbury 1983 emend. nov. (and Wallodinium sp. A), despite being subcylindrical and having apical peri- and endoarcheopyles, are similar in overall morphology to some specimens of Phallocysta elongata. This is the principal reason why the taxonomic confusion surrounding Wallodinium cylindricum and Phallocysta elongata has occurred. Using the type material of 'Fromea' elongata (Beju,1971) as an example, it is evident why the specimens in his pl. 3, fig. 7 (the holotype) and text-fig. 6A-E were interpreted as having apical periarcheopyles. The figured specimen pl. 3, fig. 8 of Beju (1971) has an intercalary periarcheopyle (see also Plate 1, figs. 1-13 herein). The phenomenon here is not periarcheopyle variability, but simply that poorly preserved specimens of Phallocysta elongata may appear to have apical periarcheopyles due to apical truncation caused by mechanical damage. The fact that this species has an anterior intercalary periarcheopyle (type 3I) was first mentioned by Feist-Burkhardt (1990, p. 615); this author also contended that the periopercula are adnate to the precingular paraplates. Study of well-preserved material from Britain confirms the periarcheopyle to be consistently intercalary. However, most of the specimens observed (and the type material) appear to have free opercula (see Plate 1, figures 1-12). Phallocysta? erregulensis (Filatoff 1975) Stover & Helby 1987 also resembles Phallocysta elongata. However, Phallocysta? erregulensis has a single paraplate peri- and endoarcheopyle. It typically has a broadly rounded apex, the pericyst may be trilobate and the endocyst may be roundedtriangular. Furthermore, Phallocysta? Erregulensis is generally epicavate but may be bicavate, circumcavate or cornucavate, Phallocysta elongata is consistently epicavate. The ambitus of Phallocysta? erregulensis is markedly variable and cornucavate forms may be laterally elongate; P. elongata invariably has an elongate pericyst. The endocyst of Phallocysta? erregulensis fills the entire hypocyst and extends into the epicyst. By contrast, Phallocysta elongata has a relatively small endocyst. The granulate morphotypes of Phallocysta elongata have low-relief, typically sparse ornamentation. The granulation, where present, of Phallocysta? erregulensis is relatively dense and is uniform and the endophragm may be spinate.
Stratigraphic and Geographic Distribution. Phallocysta elongata has been recorded from the uppermost Toarcian (D. Ievesquei Zone) to the lower Bajocian (W. Iaeviuscula Zone) (Lower-Middle Jurassic) of north- west Europe (Riding,1987; De Vains,1988; Prauss,1989; Feist-Burkhardt, 1990; Riding et al.,1991; Feist-Burkhardt and Wille, 1992, Colin et al., 1992; Riding and Thomas, 1992). Studies of independently dated material from northwest Europe indicate that the range top of this species is normally in the lowermost Bajocian (H. discites Zone) (Riding, 1987; Prauss, 1980). The report of the species from the base of the overlying S. ovalis Subzone of the W. laeviuscula Zone of Scotland by Riding et al. (1991, text-fig. A3) is based on a small number of specimens compared to relatively abundant material below. This may indicate that the S. ovalis Subzone material is reworked, a contention supported by the fact that this section was deposited in relatively high energy conditions. The original report from Romania(Beju,1971)was stated to be Bajocian-Bathonian to Callovian-Oxfordian (Middle-Upper Jurassic). The latter occurrences may represent local reworking. De Vains (1988, p. 464) also reported granulate Wallodinium spp. from the upper Toarcian (G. thouarsene Zone) of southern France. These forms, however, were not illustrated thus is is not clear if they are referable to Phallocysta elomgata. Granulate morphotypes (e.g. De Vains, 1988, p. 464; Riding et al. 1991, pl. 2, figs. 21-25; Plate 1, figure 12) tend to be confined to the upper Toarcian. Specimens from the AAlenian and lower Bajocian are consistently psilate.This distinction can be confidently used as an example of morphostratigraphy. Further study may allow a subspecific distinction to be made.