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Rhynchodiniopsis pennata
Rhynchodiniopsis pennata (Riley in Fisher and Riley, 1980) Jan du Chêne et al. 1985
Originally Gonyaulacysta, subsequently Hystrichogonyaulax, thirdly Millioudodinium, fourthly (and now) Rhynchodiniopsis.
Holotype: Fisher and Riley, 1980, pl.1, fig.10-11; Jan du Chêne et al., 1986, pl.98, fig.5
Locus typicus: Argiles de Wimereux, Boulonais, France
Stratum typicum: Late Kimmeridgian
Original diagnosis: Riley, 1980, p.321: Gonyaulacysta pennata
A species of Gonyaulacysta with an elongate-ovoidal cyst. Apex tapering to form a strong, abruptly rounded apical horn of varying length bearing a feather-like expansion formed from periphragm only. Plate boundaries indicated by low ridge formed from the periphragm, from which arise spines, either simple and isolated or confluent, particularly in the antapical region, to form a loosely constructed sutural net-like structure up to 5 µm heigth. Cingulum relatively narrow, dividing the cyst unequally, epitract larger than hypotract. Sulcus long and narrow, extending into both epitract and hypotract. Cyst wall thick, two-layered, densely, but finely granular and irregularly perforate.
Dimensions: Holotype - overall length 84 µm, breadth 47 µm, length of apical horn 5µm, length pf feather-like apical extension 12 µm, heigth of sutural-crests, up to 5 µm. Range - overall length 75-93 µm, breadth 47-68 .
Affinities:
Riley, 1980, p.321: Gonyaulacysta pennata
G. pennata differs from all previously described species of Gonyaulacysta by the combination of its distinctive sutural ornamentation and apical structure.
Originally Gonyaulacysta, subsequently Hystrichogonyaulax, thirdly Millioudodinium, fourthly (and now) Rhynchodiniopsis.
Holotype: Fisher and Riley, 1980, pl.1, fig.10-11; Jan du Chêne et al., 1986, pl.98, fig.5
Locus typicus: Argiles de Wimereux, Boulonais, France
Stratum typicum: Late Kimmeridgian
Original diagnosis: Riley, 1980, p.321: Gonyaulacysta pennata
A species of Gonyaulacysta with an elongate-ovoidal cyst. Apex tapering to form a strong, abruptly rounded apical horn of varying length bearing a feather-like expansion formed from periphragm only. Plate boundaries indicated by low ridge formed from the periphragm, from which arise spines, either simple and isolated or confluent, particularly in the antapical region, to form a loosely constructed sutural net-like structure up to 5 µm heigth. Cingulum relatively narrow, dividing the cyst unequally, epitract larger than hypotract. Sulcus long and narrow, extending into both epitract and hypotract. Cyst wall thick, two-layered, densely, but finely granular and irregularly perforate.
Dimensions: Holotype - overall length 84 µm, breadth 47 µm, length of apical horn 5µm, length pf feather-like apical extension 12 µm, heigth of sutural-crests, up to 5 µm. Range - overall length 75-93 µm, breadth 47-68 .
Affinities:
Riley, 1980, p.321: Gonyaulacysta pennata
G. pennata differs from all previously described species of Gonyaulacysta by the combination of its distinctive sutural ornamentation and apical structure.