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Polygonifera staffinensis
Polygonifera staffinensis (Gitmez, 1970, p.276–278, pl.3, fig.1; text-figs.20A–B) Davey, 1982b, p.31. Emendation: Poulsen and Riding, 1992, p.26, as Ambonosphaera? staffinensis.
NOW Ambonosphaera?. Originally Meiourogonyaulax, subsequently Lithodinia, thirdly Polygonifera, fourthly (and now) Ambonosphaera?, fifthly Lithodinia?.
Taxonomic junior synonyms: Senoniasphaera? frisia, according to Poulsen and Riding (1992, p.26); Hexagonifera (now Senoniasphaera) jurassica, according to Williams et al. (1993, p.32) — however, elsewhere in the same publication, Williams et al. (1993, p.56) retained Hexagonifera (now Senoniasphaera) jurassica.
Holotype: Gitmez, 1970, pl.3, fig.1, text-figs.20A-B
Locus typicus: Shale from 100 ft. above the second dolerite sill, Staifin Bay, Skye (SS 627), England
Stratum typicum: Early Kimmeridgian
Original diagnosis: Gitmez, 1970, p.276-277: Meiourogonyaulax staffinensis
Meiourogonyaulax having a subspherical to elongate theca, lacking the apex in all specimens seen. Tabulation: ?", ?0a, 6", 6c, 6""", 2p, 1pv and 1"""". Crests are moderately high, slightly granulate with smooth distal edges. Cingulum and sulcus are characteristically marked by deep furrows. The cingulum is slightly helicoid, laevorotatory, the sulcus broads towards the antapex. The shell surface is densely granular, sometimes tuberculate.
Dimensions: Holotype: overall length (apex lacking) 50 µm, breadth 55 µm; crests 3-8 µm high; cingulum c. 6 µm broad. Range of the English specimens (7 specimens measured): overall length (apex lacking) 48-80 µm, breadth 50-78 µm; French specimens (6 specimens measured): overall length (apex lacking) 65-75 µm, breadth 58-80 µm; Scottish samples (4 specimens measured): overall length (apex lacking) 50-60 µm, breadth 45-70 µm.
Original description: Gitmez, 1970, p.278: Meiourogonyaulax staffinensis
A proximate cyst of subspherical to elongate outline, with a dome-shaped hypotract. Because of the densely granulate surface, determination of the tabulation was difficult. The apex, with all the apical plates, was always lost to form the apical archaeopyle. No intercalary plate was observed. Six precingular plates are present: plate 1" is the smallest of the precingular plates, the others being almost uniform of size. Six postcingular plates are also present, plates 1""" and 2""" being reduced to accommodate posterior intercalary plates, 1p, 2p and 1pv; plate 6""" is much larger. The positions of the boundaries between the plates 3""" and 4""", and between the sulcus and plate 1pv, could not be confirmed. The antapex is occupied by a single plate 1"""". The cingulum is broad, not less than one tenth of the shell length, being slightly laevorotatory spiral. The sulcus is likewise broad, extending onto both epitract and hypotract, being much broader towards the posterior. The shell surface is densely granular and sometimes coarsely tuberculate. The tubercles have a diameter of approximately 0.5-1 µm; they are scattered at random over the generally finely granulate surface. The crests on the sutures are moderately high, smooth or slightly granulate and faintly striate.
Affinities:
Gitmez, 1970, p.278: Meiourogonyaulax staffinensis
Specimens were observed in the assemblages from England, Scotland and France; they differ in the nature of the crests, surface ornamentation and general aspect from all previously described species of Meiourogonyaulax.
NOW Ambonosphaera?. Originally Meiourogonyaulax, subsequently Lithodinia, thirdly Polygonifera, fourthly (and now) Ambonosphaera?, fifthly Lithodinia?.
Taxonomic junior synonyms: Senoniasphaera? frisia, according to Poulsen and Riding (1992, p.26); Hexagonifera (now Senoniasphaera) jurassica, according to Williams et al. (1993, p.32) — however, elsewhere in the same publication, Williams et al. (1993, p.56) retained Hexagonifera (now Senoniasphaera) jurassica.
Holotype: Gitmez, 1970, pl.3, fig.1, text-figs.20A-B
Locus typicus: Shale from 100 ft. above the second dolerite sill, Staifin Bay, Skye (SS 627), England
Stratum typicum: Early Kimmeridgian
Original diagnosis: Gitmez, 1970, p.276-277: Meiourogonyaulax staffinensis
Meiourogonyaulax having a subspherical to elongate theca, lacking the apex in all specimens seen. Tabulation: ?", ?0a, 6", 6c, 6""", 2p, 1pv and 1"""". Crests are moderately high, slightly granulate with smooth distal edges. Cingulum and sulcus are characteristically marked by deep furrows. The cingulum is slightly helicoid, laevorotatory, the sulcus broads towards the antapex. The shell surface is densely granular, sometimes tuberculate.
Dimensions: Holotype: overall length (apex lacking) 50 µm, breadth 55 µm; crests 3-8 µm high; cingulum c. 6 µm broad. Range of the English specimens (7 specimens measured): overall length (apex lacking) 48-80 µm, breadth 50-78 µm; French specimens (6 specimens measured): overall length (apex lacking) 65-75 µm, breadth 58-80 µm; Scottish samples (4 specimens measured): overall length (apex lacking) 50-60 µm, breadth 45-70 µm.
Original description: Gitmez, 1970, p.278: Meiourogonyaulax staffinensis
A proximate cyst of subspherical to elongate outline, with a dome-shaped hypotract. Because of the densely granulate surface, determination of the tabulation was difficult. The apex, with all the apical plates, was always lost to form the apical archaeopyle. No intercalary plate was observed. Six precingular plates are present: plate 1" is the smallest of the precingular plates, the others being almost uniform of size. Six postcingular plates are also present, plates 1""" and 2""" being reduced to accommodate posterior intercalary plates, 1p, 2p and 1pv; plate 6""" is much larger. The positions of the boundaries between the plates 3""" and 4""", and between the sulcus and plate 1pv, could not be confirmed. The antapex is occupied by a single plate 1"""". The cingulum is broad, not less than one tenth of the shell length, being slightly laevorotatory spiral. The sulcus is likewise broad, extending onto both epitract and hypotract, being much broader towards the posterior. The shell surface is densely granular and sometimes coarsely tuberculate. The tubercles have a diameter of approximately 0.5-1 µm; they are scattered at random over the generally finely granulate surface. The crests on the sutures are moderately high, smooth or slightly granulate and faintly striate.
Affinities:
Gitmez, 1970, p.278: Meiourogonyaulax staffinensis
Specimens were observed in the assemblages from England, Scotland and France; they differ in the nature of the crests, surface ornamentation and general aspect from all previously described species of Meiourogonyaulax.