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Meristaulax angulosa
Meristaulax angulosa (Gitmez, 1970) Sarjeant and Gocht in Sarjeant, 1984
Now Cribroperidinium Originally Gonyaulacysta, subsequently Acanthaulax, thirdly Meristaulax, fourthly Acanthaulax?, fifthly Rhynchodiniopsis, sixthly (and now) Cribroperidinium.
Tax. jr. synonym of Cribroperidinium granulatum (Klement, 1960) Stover and Evitt, 1978, according to Fisher and Riley, 1980. Sarjeant and Gocht in Sarjeant, 1984, retained Meristaulax angulosa as a separate species.
Stover and Williams, 1987, retained this species in Acanthaulax.
Holotype: Gitmez, 1970, pl.2, figs.4-5, text-figs.7A-B; Jan du Chêne et al., 1986, pl.2, figs. 11-15
Age: Early Kimmeridgian
Original diagnosis: Gitmez, 1970, p.252
Gonyaulacysta with a thick wall, composed of two layers; the polygonal theca terminates in a strong apical horn formed from both shell layers. Tabulation: 4', 1a, 6", 6c, 6''', 1p, 1pv, 1''''. Plates are bordered by denticulate crests of moderate height. Cingulum laevoratotory. Sulcus broad, extending onto both parts of the shell. Surface granular; simple, solid, short spines occasionally present. Single-plate precingular archaeopyle forms by loss of plate 3".
Dimensions: Holotype: overall length 75 µm, breadth 58 µm; horn length 7 µm breadth 3 µm. Range of the dimensions: overall length 65-75 µm, breadth 50-58 µm horn length 6-8 µm. Measured specimens 3 in number.
Original description: Gitmez, 1970, p.252
The elongate shell bears an apical horn which is developed from the apical plates 1', 2' and 3'; plate 4' is placed on the top of the horn. Epitract is slightly longer than the hypotract. The nearly square anterior intercalary plate ra is located between plates 3' and 6". Precingular plates are relatively large.
Six postcingular plates are present, with plates 1''' and 2''' reduced and angular in shape; an elongate posterior intercalary plate between them and antapex. Plate 4''' very large and occupies nearly the whole dorsal side of the hypotract. A single rather quadrate plate is present on the antapex; this antapical plate is separated from the sulcus by a crescent-shaped posterior ventral intercalary plate (1pv).
Affinities:
Gitmez, 1970, p.252: This is an infrequent species: of four specimens encountered, one (holotype) is well preserved, the other three are severely damaged.
This new species, in general appearance, structure and the tabulation, agrees with those of the genus Gonyaulacysta.
G. angulosa may be compared with G. cladophora because of the structure of the sutures; but the tabulation, with plates 1a, 1pv, details of the plates 4' and 1'''' and presence of the small sulcal plates, is different.
Now Cribroperidinium Originally Gonyaulacysta, subsequently Acanthaulax, thirdly Meristaulax, fourthly Acanthaulax?, fifthly Rhynchodiniopsis, sixthly (and now) Cribroperidinium.
Tax. jr. synonym of Cribroperidinium granulatum (Klement, 1960) Stover and Evitt, 1978, according to Fisher and Riley, 1980. Sarjeant and Gocht in Sarjeant, 1984, retained Meristaulax angulosa as a separate species.
Stover and Williams, 1987, retained this species in Acanthaulax.
Holotype: Gitmez, 1970, pl.2, figs.4-5, text-figs.7A-B; Jan du Chêne et al., 1986, pl.2, figs. 11-15
Age: Early Kimmeridgian
Original diagnosis: Gitmez, 1970, p.252
Gonyaulacysta with a thick wall, composed of two layers; the polygonal theca terminates in a strong apical horn formed from both shell layers. Tabulation: 4', 1a, 6", 6c, 6''', 1p, 1pv, 1''''. Plates are bordered by denticulate crests of moderate height. Cingulum laevoratotory. Sulcus broad, extending onto both parts of the shell. Surface granular; simple, solid, short spines occasionally present. Single-plate precingular archaeopyle forms by loss of plate 3".
Dimensions: Holotype: overall length 75 µm, breadth 58 µm; horn length 7 µm breadth 3 µm. Range of the dimensions: overall length 65-75 µm, breadth 50-58 µm horn length 6-8 µm. Measured specimens 3 in number.
Original description: Gitmez, 1970, p.252
The elongate shell bears an apical horn which is developed from the apical plates 1', 2' and 3'; plate 4' is placed on the top of the horn. Epitract is slightly longer than the hypotract. The nearly square anterior intercalary plate ra is located between plates 3' and 6". Precingular plates are relatively large.
Six postcingular plates are present, with plates 1''' and 2''' reduced and angular in shape; an elongate posterior intercalary plate between them and antapex. Plate 4''' very large and occupies nearly the whole dorsal side of the hypotract. A single rather quadrate plate is present on the antapex; this antapical plate is separated from the sulcus by a crescent-shaped posterior ventral intercalary plate (1pv).
Affinities:
Gitmez, 1970, p.252: This is an infrequent species: of four specimens encountered, one (holotype) is well preserved, the other three are severely damaged.
This new species, in general appearance, structure and the tabulation, agrees with those of the genus Gonyaulacysta.
G. angulosa may be compared with G. cladophora because of the structure of the sutures; but the tabulation, with plates 1a, 1pv, details of the plates 4' and 1'''' and presence of the small sulcal plates, is different.