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Subtilisphaera paeminosa

Subtilisphaera? paeminosa (Drugg, 1978) Bujak and Davies, 1983

Originally Geiselodinium, subsequently Subtilisphaera, thirdly (and now)
Subtilisphaera?. Lentin and Williams, 1985 questionably included this species in 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

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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999

Subtilisphaera? paeminosa, (Drugg, 1978) Bujak and Davies, 1983. According to Drugg (1978, p.68-69), Subtilisphaera? paeminosa has a pentagonal to broadly elliptical pericyst. The endocyst is circular to broadly elliptical. The degree of pericoel development is variable from specimen to specimen, usually present apically and antapically, and sometimes laterally. Apical horn low, broad, often with a short, blunt solid projection. Periphragm and endophragm thin, periphragm granulate to finely pustulate. Endophragm more coarsely ornamented with pustulae that sometimes grade into verrucae. Endocyst usually present. Laevorotatory cingulum denoted by low ridges, present on both endophragm and periphragm. No obvious archeopyle but three specimens without an apex. This species differs from S? inaffecta in having pustulate-verrucate ornamentation. Size: length is 49-60 µm, width 39-50 µm.
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Original description: Drugg, 1978, p. 69-70: Geiselodinium paeminosum
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 6Ám 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 µm and the width ranges from about 39 to 50 µm.

Affinities:
Drugg, 1978, p. 70: Geiselodinium paeminosum
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.

Poulsen 1996, p. 86
Subtilisphaera? paeminosa (Drugg 1978) Bujak & Davies 1983, Pl. 27, Figs. 8-9
Recorded occurrences.
Denmark: Endoscrinium luridum Zone, Perisseiasphaeridium pannosum Subzone - Glossodinium dimorphum Zone, Subzone a.
Poland: Rare occurrence from the earliest Divisum Zone, common from mid-Divisum to Autissiodorensis Zones.
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