Back
Rhynchodiniopsis tenuitabulata
Rhynchodiniopsis tenuitabulata (Gerlach, 1961) emend. Sarjeant, 1984
Now Cribroperidinium. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly Millioudodinium, fourthly (and now) Cribroperidinium, fifthly Rhynchodiniopsis. Lentin and Williams, 1985 retained this species in Cribroperidinium.
Holotype: Gerlach, 1961, pl.25, figs.10-11
Lectotype: Sarjeant, 1984, pl.2, fig.3; pl.4, fig.3
Paratype: Sarjeant, 1984
Locus typicus: Emsb³ren boring no. 7, NW Germany
Stratum typicum: Middle Oligocene-middle Miocene
Translation Gerlach, 1961: Sarjeant, 1984
Original diagnosis: Gerlach, 1961, p. 160: Gonyaulax tenuitabulatum
Shell thin-walled, broadly spheroidal, with short, blunt apical horn. Tabulation pattern: 4", 6", 6""", 1p, 1pv, 1"""". Plates enclosed by low, narrow crests. Girdle furrow spiral, with an offset of about 1 1/2 furrow widths. Membrane finely granulate.
Emended diagnosis: Sarjeant, 1984, p.77-78
Cyst proximate, holotabulate, apically cornucavate (monocornucavate). Ambitus spheroidal to broadly rounded-subpolygonal, with epitract and hypotract of almost equal shape and relative size. Apical horn short, tapering and blunt. Low, narrow crests, entire to undulate distally, delimit the paraplates: the crests on the horn may impart to it a trifid appearance. Paratabulation 2pr, 4", 6", 6c, 6""", 1p, 1"""", ?8s. Paraplate 4" is quite large and asymmetrically quadrate, having a long boundary with an almost rectangular 6"; their mutual boundary intersects that of paraplate 1" just anterior to the junction of the latter paraplate with the sulcus. Paraplate 1" broadens considerably in its posterior portion. Paraplate 3" is unusually small, whereas paraplates 2" and 3" are somewhat larger than usual. Paraplate 1""" is reduced and elongate and 2""" reduced and quadrate, both paraplates being separated from the antapex by paraplate 1p. Cingulum of moderate breadth and degree of spirality, its two ends differing in anteroposterior position by 1 1/2 times its width. The sulcus is moderately broad, extending from mid-point on the epitract to the antapex; it is subdivided by faint lines into at least six, perhaps eight or more, small paraplates. Surface of phragma granulate. Archaeopyle single-plate precingular (type P), formed by loss of paraplate 3": operculum free. Dimensions. Holotype: overall length 84µm, breadth 74.5 µm. Lectotype: overall length 88 µm, breadth 79.7 µm. Paratype: overall length 84 µm, breadth 77.8 µm. Range of dimensions: overall length 84-93 µm (mean 88,1 µm), breadth 74.5-95 µm (mean 82 µm). Material: 10 specimens.
Now Cribroperidinium. Originally Gonyaulax, subsequently Gonyaulacysta, thirdly Millioudodinium, fourthly (and now) Cribroperidinium, fifthly Rhynchodiniopsis. Lentin and Williams, 1985 retained this species in Cribroperidinium.
Holotype: Gerlach, 1961, pl.25, figs.10-11
Lectotype: Sarjeant, 1984, pl.2, fig.3; pl.4, fig.3
Paratype: Sarjeant, 1984
Locus typicus: Emsb³ren boring no. 7, NW Germany
Stratum typicum: Middle Oligocene-middle Miocene
Translation Gerlach, 1961: Sarjeant, 1984
Original diagnosis: Gerlach, 1961, p. 160: Gonyaulax tenuitabulatum
Shell thin-walled, broadly spheroidal, with short, blunt apical horn. Tabulation pattern: 4", 6", 6""", 1p, 1pv, 1"""". Plates enclosed by low, narrow crests. Girdle furrow spiral, with an offset of about 1 1/2 furrow widths. Membrane finely granulate.
Emended diagnosis: Sarjeant, 1984, p.77-78
Cyst proximate, holotabulate, apically cornucavate (monocornucavate). Ambitus spheroidal to broadly rounded-subpolygonal, with epitract and hypotract of almost equal shape and relative size. Apical horn short, tapering and blunt. Low, narrow crests, entire to undulate distally, delimit the paraplates: the crests on the horn may impart to it a trifid appearance. Paratabulation 2pr, 4", 6", 6c, 6""", 1p, 1"""", ?8s. Paraplate 4" is quite large and asymmetrically quadrate, having a long boundary with an almost rectangular 6"; their mutual boundary intersects that of paraplate 1" just anterior to the junction of the latter paraplate with the sulcus. Paraplate 1" broadens considerably in its posterior portion. Paraplate 3" is unusually small, whereas paraplates 2" and 3" are somewhat larger than usual. Paraplate 1""" is reduced and elongate and 2""" reduced and quadrate, both paraplates being separated from the antapex by paraplate 1p. Cingulum of moderate breadth and degree of spirality, its two ends differing in anteroposterior position by 1 1/2 times its width. The sulcus is moderately broad, extending from mid-point on the epitract to the antapex; it is subdivided by faint lines into at least six, perhaps eight or more, small paraplates. Surface of phragma granulate. Archaeopyle single-plate precingular (type P), formed by loss of paraplate 3": operculum free. Dimensions. Holotype: overall length 84µm, breadth 74.5 µm. Lectotype: overall length 88 µm, breadth 79.7 µm. Paratype: overall length 84 µm, breadth 77.8 µm. Range of dimensions: overall length 84-93 µm (mean 88,1 µm), breadth 74.5-95 µm (mean 82 µm). Material: 10 specimens.