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Geiselodinium paeminosum
Geiselodinium paeminosum Drugg, 1978, p.68-69
Originally Geiselodinium, subsequently Subtilisphaera, thirdly Subtilisphaera?.
Taxonomic senior synonym: Geiselodinium (now Corculodinium) inaffectum, according to Courtinat (2000, p.173).
Holotype: Drugg, 1978, pl.3, fig.8
Isotypes: Drugg, 1978, pl.3, figs.5--7,9
Locus typicus: Samkeweg, Saxony, Germany
Stratum typicum: Middle Kimmeridgian
Original description: Drugg, 1978, p. 69-70
Cyst outline pentagonal to broadly elliptical. Endocyst circular to broadly elliptical.
Degree of pericoel development variable from specimen to specimen, usually present apically and antapically, sometimes present laterally as well. Apical horn low and broad, often capped with a short, blunt, solid projection. Endophragm slightly thicker than periphragm but both are thin. Periphragm granulate to finely pustulate. Endophragm more coarsely ornamented with pustulae which sometimes grade into verrucae. Most specimens exhibit an endocyst but occasionally it is lacking. Laevorotatory paracingulum about 6 Ám wide is delineated by low ridges which are present on both endophragm and periphragm but are slightly more pronounced on the endophragm. Numerous specimens examined and any suggestions of an archeopyle are virtually lacking. Three specimens, however, were missing the apical portions of the cyst but the breaks could be accidental. One specimen also exhibits a partial separation at the paracingulum which is probably accidental. The overall length ranges from about 49 to 60 Ám and the width ranges from about 39 to 50 Ám.
Affinities:
Drugg, 1978, p. 70: This species closely resembles Geiselodinium inaffectum but differs primarily in possessing a pustulate-verrucate ornamentation. Both species occur at about the samc stratigraphic level and are closely related. There is no doubt that the lack of any archeopyle development is typical of this species.
However three specimens exhibit what could be interpreted as an apical archeopyle. If so then this species perhaps should be transferred to Ovoidinium Davey, 1970.
Originally Geiselodinium, subsequently Subtilisphaera, thirdly Subtilisphaera?.
Taxonomic senior synonym: Geiselodinium (now Corculodinium) inaffectum, according to Courtinat (2000, p.173).
Holotype: Drugg, 1978, pl.3, fig.8
Isotypes: Drugg, 1978, pl.3, figs.5--7,9
Locus typicus: Samkeweg, Saxony, Germany
Stratum typicum: Middle Kimmeridgian
Original description: Drugg, 1978, p. 69-70
Cyst outline pentagonal to broadly elliptical. Endocyst circular to broadly elliptical.
Degree of pericoel development variable from specimen to specimen, usually present apically and antapically, sometimes present laterally as well. Apical horn low and broad, often capped with a short, blunt, solid projection. Endophragm slightly thicker than periphragm but both are thin. Periphragm granulate to finely pustulate. Endophragm more coarsely ornamented with pustulae which sometimes grade into verrucae. Most specimens exhibit an endocyst but occasionally it is lacking. Laevorotatory paracingulum about 6 Ám wide is delineated by low ridges which are present on both endophragm and periphragm but are slightly more pronounced on the endophragm. Numerous specimens examined and any suggestions of an archeopyle are virtually lacking. Three specimens, however, were missing the apical portions of the cyst but the breaks could be accidental. One specimen also exhibits a partial separation at the paracingulum which is probably accidental. The overall length ranges from about 49 to 60 Ám and the width ranges from about 39 to 50 Ám.
Affinities:
Drugg, 1978, p. 70: This species closely resembles Geiselodinium inaffectum but differs primarily in possessing a pustulate-verrucate ornamentation. Both species occur at about the samc stratigraphic level and are closely related. There is no doubt that the lack of any archeopyle development is typical of this species.
However three specimens exhibit what could be interpreted as an apical archeopyle. If so then this species perhaps should be transferred to Ovoidinium Davey, 1970.