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Rhynchodiniopsis cladophora
Rhynchodiniopsis cladophora (Deflandre, 1938) Below, 1981
Originally Gonyaulax, subsequently Gonyaulacysta, thirdly Hystrichogonyaulax, fourthly (and now) Rhynchodiniopsis.
Tax. sr. synonym of Apteodinium (originally Gonyaulacysta) gottisii (Dupin, 1968) Helenes, 1984, according to Jan du Chene et al., 1986 and Jan du Chene and Fauconnier, 1986.
Tax. sr. synonym of Gonyaulacysta (as Hystrichogonyaulax) canadensis Pocock, 1972, according to Fisher and Riley, 1980. Jansonius, 1986 retained Gonyaulacysta (as Rhynchodiniopsis) canadensis as a separate species, but Kunz, 1990 agreed with Fisher and Riley, 1980.
Tax. sr. synonym of Gonyaulacysta downiei Pocock, 1972, according to Fisher and Riley, 1980. Jansonius, 1986 retained Gonyaulacysta (as Rhynchodiniopsis) downiei as a separate species, but Kunz, 1990 agreed with Fisher and Riley, 1980. Brenner, 1988 stated that Rhynchodiniopsis cladophora ssp. hemipolyedrica (Klement, 1960) Below, 1981, Rhynchodiniopsis cladophora ssp. extensa (Klement, 1960) Below, 1981 and Rhynchodiniopsis cladophora ssp. isovaluata (Klement, 1960) Below, 1981 are jr. synonyms of Rhynchodiniopsis cladophora. Lentin and Williams, 1993, presumed that Brenner intended to imply that the three subspecies are tax. jr. synonyms of the autonym Rhynehodiniopsis cladophora ssp. eladophora. However, pending clarification of this point, they retained the three subspecies as separate taxa. Lentin and Williams, 1981 retained the species in Hystrichogonyaulax Sarjeant, 1969; however, Jan du Chene et al., 1986 agreed with Below, 1981.
Holotype: Deflandre, 1938, pl.7, fig.1; Jan du Chene et al., 1986, pl.94, fig.6
Paratpes: Deflandre, 1938
Locus typicus: Villers-sur-Mer, Calvados, France
Stratum typicum: Early Oxfordian
Translation Deflandre, 1938: LPP
Translation Courtinat, 1989: LPP
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rhynchodiniopsis cladophora (Deflandre, 1939a) Below, 1981a. Rhynchodiniopsis has a well developed but short apical horn. It has a tabulation of 1-2PR, 4', 1-2a, 6", Xc, 6"’, 1p, 1"”. The parasutures are denoted by septa which distally are crested, bearing spines that can be acuminate or bifid distally. Size: length 68-117 µm, width 86-102 µm.
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Deflandre 1938, p.173-176: Gonyaulax cladophora.
Annotated description: body spherical, but appears sometimes somewhat polyhedrical, especially with flattened specimens. The sides are almost always convex, however deformed they may be. The strongly helicoidal transverse furrow separates the theca in two nearly equal parts. The epitheca bears a tabulated apical horn, usually denticulate at its extremity. The hypotheca is regularly rounded, nearly semispherical. The longitudinal furrow extends from the apex to the antapex and mostly widens on the hypovalve. The plates are limited by series of horns, sometimes reduced to spines, which branch in an irregular way, producing short branches, which again end in small spines. Often these processes are simply furcated, but sometimes double or triple furcations occur.
Because of the lack of complete or well-oriented specimens, the tabulation could not be established. However, many specimens show the ventral area, and the presence of a very small postequatorial plate could be demonstrated. The epitheca possesses six pre-equatorial plates, the first and the sixth being considerably smaller than the others. The ventral view shows, near the apex, the existence of at least two plates on the right side, and one on the left.
The tabulation of the hypotheca is less unclear: six postequatorial plates, the first of which is very reduced and hard to see. The antapical plate, almost quadrangular, is connected to two first postequatorial plates by an intermediate plate, and the whole corresponds to the tabulation characteristic of Gonyaulax. This antapical plate shows a rectangular recess, where the longitudinal furrow and the intermediate plate end.
The holotype is 95 µm long and 95 µm wide. This may be a mean value, but dimensions vary considerably (e.g. length: 68-117 µm). Some specimens may be wider than long.
The membrane of the theca is, often indistinctly, punctate, which becomes visible only after coloration.
Remark: Courtinat, 1989, p.204
R. cladophora represents a species group taking into account the fact that these forms are essentially marked by the nature of the processes on the septa. These forms present different paratabulations of the preapical and anterior intercalary paraplates. The orientation of Deflandre's holotype does not allow an interpretation of the epicyst paratabulation as far as the above-mentioned are concerned. Klement (1960) erects 4 subspecies which, at least some of them, differ from the type cladophora cladophora. The subspecies hemipolyedrica does not possess the horn of cladophora. The wall of R. cladophora is strongly granulate and not perforate; the archaeopyle is reduced (the detachment takes place parallel to the sutures and not at the sutures). In the holotype, the gonal processes are more robust. The specimens from the Jura, which strictly present these characteristics, show a Q/B type apical arrangement and an anterior intercalary paraplate. Other specimens show two anterior intercalary paraplates; finally, some specimens have neither anterior intercalary paraplates nor a horn. In that case the cyst wall is smooth. These different forms correspond to characteristic species; but to be able to designate them one would have to describe anew those species synonymized with R. cladophora, "Gonyaulacysta" canandensis Pocock,"Gonyaulacysta" downiei Pocock.
Originally Gonyaulax, subsequently Gonyaulacysta, thirdly Hystrichogonyaulax, fourthly (and now) Rhynchodiniopsis.
Tax. sr. synonym of Apteodinium (originally Gonyaulacysta) gottisii (Dupin, 1968) Helenes, 1984, according to Jan du Chene et al., 1986 and Jan du Chene and Fauconnier, 1986.
Tax. sr. synonym of Gonyaulacysta (as Hystrichogonyaulax) canadensis Pocock, 1972, according to Fisher and Riley, 1980. Jansonius, 1986 retained Gonyaulacysta (as Rhynchodiniopsis) canadensis as a separate species, but Kunz, 1990 agreed with Fisher and Riley, 1980.
Tax. sr. synonym of Gonyaulacysta downiei Pocock, 1972, according to Fisher and Riley, 1980. Jansonius, 1986 retained Gonyaulacysta (as Rhynchodiniopsis) downiei as a separate species, but Kunz, 1990 agreed with Fisher and Riley, 1980. Brenner, 1988 stated that Rhynchodiniopsis cladophora ssp. hemipolyedrica (Klement, 1960) Below, 1981, Rhynchodiniopsis cladophora ssp. extensa (Klement, 1960) Below, 1981 and Rhynchodiniopsis cladophora ssp. isovaluata (Klement, 1960) Below, 1981 are jr. synonyms of Rhynchodiniopsis cladophora. Lentin and Williams, 1993, presumed that Brenner intended to imply that the three subspecies are tax. jr. synonyms of the autonym Rhynehodiniopsis cladophora ssp. eladophora. However, pending clarification of this point, they retained the three subspecies as separate taxa. Lentin and Williams, 1981 retained the species in Hystrichogonyaulax Sarjeant, 1969; however, Jan du Chene et al., 1986 agreed with Below, 1981.
Holotype: Deflandre, 1938, pl.7, fig.1; Jan du Chene et al., 1986, pl.94, fig.6
Paratpes: Deflandre, 1938
Locus typicus: Villers-sur-Mer, Calvados, France
Stratum typicum: Early Oxfordian
Translation Deflandre, 1938: LPP
Translation Courtinat, 1989: LPP
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Rhynchodiniopsis cladophora (Deflandre, 1939a) Below, 1981a. Rhynchodiniopsis has a well developed but short apical horn. It has a tabulation of 1-2PR, 4', 1-2a, 6", Xc, 6"’, 1p, 1"”. The parasutures are denoted by septa which distally are crested, bearing spines that can be acuminate or bifid distally. Size: length 68-117 µm, width 86-102 µm.
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Deflandre 1938, p.173-176: Gonyaulax cladophora.
Annotated description: body spherical, but appears sometimes somewhat polyhedrical, especially with flattened specimens. The sides are almost always convex, however deformed they may be. The strongly helicoidal transverse furrow separates the theca in two nearly equal parts. The epitheca bears a tabulated apical horn, usually denticulate at its extremity. The hypotheca is regularly rounded, nearly semispherical. The longitudinal furrow extends from the apex to the antapex and mostly widens on the hypovalve. The plates are limited by series of horns, sometimes reduced to spines, which branch in an irregular way, producing short branches, which again end in small spines. Often these processes are simply furcated, but sometimes double or triple furcations occur.
Because of the lack of complete or well-oriented specimens, the tabulation could not be established. However, many specimens show the ventral area, and the presence of a very small postequatorial plate could be demonstrated. The epitheca possesses six pre-equatorial plates, the first and the sixth being considerably smaller than the others. The ventral view shows, near the apex, the existence of at least two plates on the right side, and one on the left.
The tabulation of the hypotheca is less unclear: six postequatorial plates, the first of which is very reduced and hard to see. The antapical plate, almost quadrangular, is connected to two first postequatorial plates by an intermediate plate, and the whole corresponds to the tabulation characteristic of Gonyaulax. This antapical plate shows a rectangular recess, where the longitudinal furrow and the intermediate plate end.
The holotype is 95 µm long and 95 µm wide. This may be a mean value, but dimensions vary considerably (e.g. length: 68-117 µm). Some specimens may be wider than long.
The membrane of the theca is, often indistinctly, punctate, which becomes visible only after coloration.
Remark: Courtinat, 1989, p.204
R. cladophora represents a species group taking into account the fact that these forms are essentially marked by the nature of the processes on the septa. These forms present different paratabulations of the preapical and anterior intercalary paraplates. The orientation of Deflandre's holotype does not allow an interpretation of the epicyst paratabulation as far as the above-mentioned are concerned. Klement (1960) erects 4 subspecies which, at least some of them, differ from the type cladophora cladophora. The subspecies hemipolyedrica does not possess the horn of cladophora. The wall of R. cladophora is strongly granulate and not perforate; the archaeopyle is reduced (the detachment takes place parallel to the sutures and not at the sutures). In the holotype, the gonal processes are more robust. The specimens from the Jura, which strictly present these characteristics, show a Q/B type apical arrangement and an anterior intercalary paraplate. Other specimens show two anterior intercalary paraplates; finally, some specimens have neither anterior intercalary paraplates nor a horn. In that case the cyst wall is smooth. These different forms correspond to characteristic species; but to be able to designate them one would have to describe anew those species synonymized with R. cladophora, "Gonyaulacysta" canandensis Pocock,"Gonyaulacysta" downiei Pocock.