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Meiourogonyaulax pila
Meiourogonyaulax pila Gitmez and Sarjeant, 1972
Originally (and now) Meiourogonyaulax, subsequently Lithodinia. This species is here retained in Meiourogonyaulax following the retention of the genus by Riding and Helby (2001d, p.81,83).
Gocht, 1976, transferred this species to Lithodinia Eisenack, 1935. Stover and Evitt, 1978, retained it in Meiourogonyaulax. Williams et al., 1993, agreed with Gocht, 1976.
Holotype: Gitmez and Sarjeant, 1972, pl.4, fig.5, text-fig.23
Locus typicus: Dorset, England
Stratum typicum: Middle-Late Kimmeridgian
Original diagnosis: Gitmez and Sarjeant, 1972, p.226
Cyst almost circular in outline, without an apical horn and rounded at the antapex. Wall moderately thin, surface finely granular. Tabulation 4", 6", 6c, 6""", 1p, 1pv, 1"""". Plate boundaries faintly indicated. The cingulum forms a feebly laevorotatory spiral. Apical archaeopyle typically present, with operculum attached ventrally.
Dimensions: Holotype: overall length 60 Ám, breadth 55 Ám. Range of the observed specimens (19 in number): length 55-75 Ám breadth 55-70 Ám.
Original description: Gitmez and Sarjeant, 1972, p.226-227
The spherical cyst is divided by the moderately wide and more or less equitorial cingulum into two parts, the epitract and the hypotract; these may be equal in size or the hypotract may be slightIy longer than the epitract. The sulcus is relatively short, mainly placed on the hypotract. Plate 1" is elongate, the other three apical plates are more or less similar in shape and size. The precingular plates are generally almost equal in size, except that plate 6" is smaller than the others. The postcingular plates are of variable size; plate 1""" is relatively smalI, plate 4""" is the largest of all the pIates. A quite large intercalary plate (1p) is situated between the plates 2""" and 1""""; plate 2""" is correspondingly reduced. A large postcrior ventral plate (1pv) separates the sulcus from the antapex. A single antapical plate, broad and slightly convex, occupies the antapex. PIate boundaries are marked by low ridges.
Remark:
Courtinat, 1989, p.178: Meiourogonyaulax cf. valensi and M. cf. pilla
M. cf. alensi possesses serrate crests but the septa are less well developed than in M. valensi. M. cf. pilla presents an autophragm without traces of paratabulation except for the paracingulum, whilst M. pilla is characterized by a faint paratabulation indicated by delicate ribs.
Originally (and now) Meiourogonyaulax, subsequently Lithodinia. This species is here retained in Meiourogonyaulax following the retention of the genus by Riding and Helby (2001d, p.81,83).
Gocht, 1976, transferred this species to Lithodinia Eisenack, 1935. Stover and Evitt, 1978, retained it in Meiourogonyaulax. Williams et al., 1993, agreed with Gocht, 1976.
Holotype: Gitmez and Sarjeant, 1972, pl.4, fig.5, text-fig.23
Locus typicus: Dorset, England
Stratum typicum: Middle-Late Kimmeridgian
Original diagnosis: Gitmez and Sarjeant, 1972, p.226
Cyst almost circular in outline, without an apical horn and rounded at the antapex. Wall moderately thin, surface finely granular. Tabulation 4", 6", 6c, 6""", 1p, 1pv, 1"""". Plate boundaries faintly indicated. The cingulum forms a feebly laevorotatory spiral. Apical archaeopyle typically present, with operculum attached ventrally.
Dimensions: Holotype: overall length 60 Ám, breadth 55 Ám. Range of the observed specimens (19 in number): length 55-75 Ám breadth 55-70 Ám.
Original description: Gitmez and Sarjeant, 1972, p.226-227
The spherical cyst is divided by the moderately wide and more or less equitorial cingulum into two parts, the epitract and the hypotract; these may be equal in size or the hypotract may be slightIy longer than the epitract. The sulcus is relatively short, mainly placed on the hypotract. Plate 1" is elongate, the other three apical plates are more or less similar in shape and size. The precingular plates are generally almost equal in size, except that plate 6" is smaller than the others. The postcingular plates are of variable size; plate 1""" is relatively smalI, plate 4""" is the largest of all the pIates. A quite large intercalary plate (1p) is situated between the plates 2""" and 1""""; plate 2""" is correspondingly reduced. A large postcrior ventral plate (1pv) separates the sulcus from the antapex. A single antapical plate, broad and slightly convex, occupies the antapex. PIate boundaries are marked by low ridges.
Remark:
Courtinat, 1989, p.178: Meiourogonyaulax cf. valensi and M. cf. pilla
M. cf. alensi possesses serrate crests but the septa are less well developed than in M. valensi. M. cf. pilla presents an autophragm without traces of paratabulation except for the paracingulum, whilst M. pilla is characterized by a faint paratabulation indicated by delicate ribs.