Back
Dichadogonyaulax irregularis
Dichadogonyaulax irregularis Benson, 1985
Holotype: Benson, 1985, pl.2, figs.5-6
Locus typicus: Winn Parish, Louisiana, USA
Stratum typicum: Neocomian
Original description: Benson, 1985, p. 154
Gonyaulacoid dinocyst with epicystal (type E) archeopyle, operculum generally free. Paratabulation formula: 1pr, 4", 0a, 6""", xc, 1p, 6"""", xs, expressed by discontinuous parasutural crests which are ornamented with acuminate spines of varying lengths. Paraplates 2" and 4" in contact, preapical paraplate displaced posteroventrally. Antapical paraplate only slightly asymmetric and very large (pl. 2, figs. 11, 12). Cyst surface chagrenate to microreticulate.
Dimensions: Holotype: 49 Ám in diameter. Range: 43 (48.5) 51 Ám in diameter (20 specimens).
Affinities:
Benson, 1985, p. 154: D. irregulare is most similar to D. pannea but differs by being slightly smaller, having parasutural crests that are discontinuous in distribution, and by having higher crest ornamentation on the epicyst. D. irregulare differs from D. culmula in having accuminate terminations on the crest spines rather than bifid terminations as in D. culmula. In addition, the parasutural crests of D. irregulare do not exhibit the basal perforations that are present in D. culmula. The antapical paraplate is larger than in other species of Dichadogonyaulax, generally being about half the diameter of the hypocyst.
Holotype: Benson, 1985, pl.2, figs.5-6
Locus typicus: Winn Parish, Louisiana, USA
Stratum typicum: Neocomian
Original description: Benson, 1985, p. 154
Gonyaulacoid dinocyst with epicystal (type E) archeopyle, operculum generally free. Paratabulation formula: 1pr, 4", 0a, 6""", xc, 1p, 6"""", xs, expressed by discontinuous parasutural crests which are ornamented with acuminate spines of varying lengths. Paraplates 2" and 4" in contact, preapical paraplate displaced posteroventrally. Antapical paraplate only slightly asymmetric and very large (pl. 2, figs. 11, 12). Cyst surface chagrenate to microreticulate.
Dimensions: Holotype: 49 Ám in diameter. Range: 43 (48.5) 51 Ám in diameter (20 specimens).
Affinities:
Benson, 1985, p. 154: D. irregulare is most similar to D. pannea but differs by being slightly smaller, having parasutural crests that are discontinuous in distribution, and by having higher crest ornamentation on the epicyst. D. irregulare differs from D. culmula in having accuminate terminations on the crest spines rather than bifid terminations as in D. culmula. In addition, the parasutural crests of D. irregulare do not exhibit the basal perforations that are present in D. culmula. The antapical paraplate is larger than in other species of Dichadogonyaulax, generally being about half the diameter of the hypocyst.