Back
Glabridinium apatelum
Glabridinium apatelum (Cookson and Eisenack, 1960b, p.249, pl.37, figs.12–13) Brideaux, 1977, p.35. Emendation: Sarjeant, 1982b, p.42, as Tubotuberella apatela.
Now Tubotuberella. Originally Scriniodinium, subsequently Psaligonyaulax, thirdly (and now) Tubotuberella, fourthly Glabridinium.
Sarjeant, 1982, retained this species in Tubotuberella Vozzhennikova, 1967.
Holotype: Cookson and Eisenack, 1960b, pl.37, fig.12; Jan du Chêne et al., 1986a, pl.124, figs.1–2; Fensome et al., 1993a, fig.1 — p.921.
Locus typicus: Canning Basin, W Austalia
Stratum typicum: Oxfordian-Lower Kimmeridgian
Age: Late Jurassic
Original description: Cookson and Eisenack, 1960, p. 249: Scriniodinium apatelum
Shell flat, the main portion ovoidal to somewhat rhomboidal; epitheca with a small, thin-walled, cylindrical and truncate horn; hypotheca narrowing distally towards a square opening with a smooth or serrated edge and sometimes with a short spine-like projection at each angle. The girdle is circular, occasionally well marked but usually only indicated by narrow ledges on the two sides. Membranes of shell thin, smooth, perforate or serrate at the sides. The capsule, which fills the shell laterally and follows its outline in the middle region, terminates in a short apical prominence. A relatively large, hoof-shaped pylome extends from just beneath the apex to the level of the girdle. Dimensions: Holotype 120 µm long, 58 µm broad; capsule 80 µm long, 58 µm broad. Range 70-145 µm x 42-72 µm.
Supplemental diagnosis: Brideaux, 1977, p. 35
As for the genus with these particular features: pericyst length/width ratio approximately two to one, pericyst tapering gently at the apex; endocyst ovoid to subrhombic, the epiendocyst slightly longer than the hypoendocyst; peri- and endoperculum elongate, hoof-shaped; pericingulum indistinct, marked by narrow, thin cingular parasutures slightly below the mid-latitude of the pericyst; and perisulcus absent.
Affinities:
Cookson and Eisenack, 1960, p. 249: Scriniodinium apatelum
S. apelatum has some of the features of Gonyaulax jurassica Defl. and G. eisenacki Defl., but non of the specimens have shown any sign of tabulation.
Brideaux, 1977, p. 35: The species is distinguished from Tubotuberella rhomkiformis Vozzhennikova by the absence of paratabulation and development of an apical horn.
Now Tubotuberella. Originally Scriniodinium, subsequently Psaligonyaulax, thirdly (and now) Tubotuberella, fourthly Glabridinium.
Sarjeant, 1982, retained this species in Tubotuberella Vozzhennikova, 1967.
Holotype: Cookson and Eisenack, 1960b, pl.37, fig.12; Jan du Chêne et al., 1986a, pl.124, figs.1–2; Fensome et al., 1993a, fig.1 — p.921.
Locus typicus: Canning Basin, W Austalia
Stratum typicum: Oxfordian-Lower Kimmeridgian
Age: Late Jurassic
Original description: Cookson and Eisenack, 1960, p. 249: Scriniodinium apatelum
Shell flat, the main portion ovoidal to somewhat rhomboidal; epitheca with a small, thin-walled, cylindrical and truncate horn; hypotheca narrowing distally towards a square opening with a smooth or serrated edge and sometimes with a short spine-like projection at each angle. The girdle is circular, occasionally well marked but usually only indicated by narrow ledges on the two sides. Membranes of shell thin, smooth, perforate or serrate at the sides. The capsule, which fills the shell laterally and follows its outline in the middle region, terminates in a short apical prominence. A relatively large, hoof-shaped pylome extends from just beneath the apex to the level of the girdle. Dimensions: Holotype 120 µm long, 58 µm broad; capsule 80 µm long, 58 µm broad. Range 70-145 µm x 42-72 µm.
Supplemental diagnosis: Brideaux, 1977, p. 35
As for the genus with these particular features: pericyst length/width ratio approximately two to one, pericyst tapering gently at the apex; endocyst ovoid to subrhombic, the epiendocyst slightly longer than the hypoendocyst; peri- and endoperculum elongate, hoof-shaped; pericingulum indistinct, marked by narrow, thin cingular parasutures slightly below the mid-latitude of the pericyst; and perisulcus absent.
Affinities:
Cookson and Eisenack, 1960, p. 249: Scriniodinium apatelum
S. apelatum has some of the features of Gonyaulax jurassica Defl. and G. eisenacki Defl., but non of the specimens have shown any sign of tabulation.
Brideaux, 1977, p. 35: The species is distinguished from Tubotuberella rhomkiformis Vozzhennikova by the absence of paratabulation and development of an apical horn.