Hystrichogonyaulax cladophora (Deflandre, 1938) Stover and Evitt, 1987

Now Rhynchodiniopsis. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly Hystrichogonyaulax, fourthly (and now) Rhynchodiniopsis.
Tax. sr. synonym of Gonyaulacysta gottisii Dupin, 1968, according to Jan du Chêne et al., 1986, and Jan du Chêne and Fauconnier, 1986.
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.
Tax. sr. synonym of Gonyaulax canadensis Pocock, 1972, according to Fisher and Riley, 1980. Jansonius, 1986, retained that species as Rhynchodiniopsis canadensis (Pocock, 1972) Jansonius, 1986, but Kunz, 1990, agreed with Fisher and Riley, 1980.
Brenner, 1988, stated that Hystrichogonyaulax (as Rhynchodiniopsis) cladophora ssp. hemipolyedrica (Klement, 1960) Stover and Evitt, 1978, Hystrichogonyaulax (as Rhynchodiniopsis) cladophora ssp. extensa (Klement, 1960) Stover and Evitt, 1978 and Hystrichogonyaulax (as Rhynchodiniopsis) cladophora ssp. isovalvata (Klement, 1960) Stover and Evitt, 1978 are jr. synonyms of Hystrichogonyaulax (as Rhynchodiniopsis) cladophora. Lentin and Williams, 1993, presumed that Brenner intended to imply that the three subspecies are tax. jr. synonyms of the autonym Hystrichogonyaulax (as Rhynchodiniopsis) cladophora ssp. cladophora. However, pending clarification of this point, they retained the three subspecies as separate taxa.

Holotype: Deflandre, 1938, pl.7, fig.1; Jan du Chêne 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

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 interm ediate plate end.
The holotype is 95 Ám long and 95 Ám wide. This may be a mean value, but dimensions vary considerably (e.g. length: 68-117 Ám). Some specimens may be wider than long.
The membrane of the theca is, often indistinctly, punctate, which becomes visible only after coloration.