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Acanthaulax downiei
From Fensome et al., 2019:
Acanthaulax ?downiei, (Sarjeant, 1960a, p. 138-139), Sarjeant, 1976c, p. 6.
Holotype: Downie, 1957, pl.20, fig.10, as Hystrichosphaeridium pattei; Jan du Chêne et al., 1986a, pl.3, figs.7–9.
NOW Cribroperidinium?.
Originally Baltisphaeridium (Appendix A), subsequently Acanthaulax, thirdly Acanthaulax?, fourthly Cyclonephelium, fifthly (and now) Cribroperidinium?
Questionable assignment: Stover and Evitt (1978, p.137) — however, Sarjeant (1982b, p.47) retained the species in Acanthaulax without question.
Age: Kimmeridgian.
Locus typicus: France
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Original description as Hystrichosphaeridium pattei: [Downie, 1957, p. 425]:
Description:
The test is sphaerical, 32 - 50 µm in diameter. There is a very large number of small processes, 4 - 5 µm long, forking distally into two short branches with a wide angle between. The figure indicates low ridges linking the processes.
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Description as Baltisphaeridium downiei:
Sarjeant, 1960, p. 138:
Diagnosis:
A species of Baltisphaeridium having a spheroidal to ovoidal shell densely covered by very short spines, knobbed or briefly bifurcate, sometimes connected by low ridges on the shell surface. The spines are in number such that 70 to 90 are seen around the shell periphery: their length is of the order of one-thirtieth the longest shell diameter.
Dimensions:
Type specimen: overall long diameter 50 µm, short diameter 45 µm (slightly damaged). Spines 1 to 1.5 µm in length. Range: overall diameters 32 to 50 µm.
Affinities: (p. 139):
Baltisphaeridium downiei differs from Baltisphaeridium fimbriatum (White, 1842) of the Cretaceous of England, and from Baltisphaeridium cf. fimbriatum (White) Sarjeant, 1960, in the relative length of its processes, around one-thirtieth instead of one-tenth the shell diameter.
Acanthaulax ?downiei, (Sarjeant, 1960a, p. 138-139), Sarjeant, 1976c, p. 6.
Holotype: Downie, 1957, pl.20, fig.10, as Hystrichosphaeridium pattei; Jan du Chêne et al., 1986a, pl.3, figs.7–9.
NOW Cribroperidinium?.
Originally Baltisphaeridium (Appendix A), subsequently Acanthaulax, thirdly Acanthaulax?, fourthly Cyclonephelium, fifthly (and now) Cribroperidinium?
Questionable assignment: Stover and Evitt (1978, p.137) — however, Sarjeant (1982b, p.47) retained the species in Acanthaulax without question.
Age: Kimmeridgian.
Locus typicus: France
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Original description as Hystrichosphaeridium pattei: [Downie, 1957, p. 425]:
Description:
The test is sphaerical, 32 - 50 µm in diameter. There is a very large number of small processes, 4 - 5 µm long, forking distally into two short branches with a wide angle between. The figure indicates low ridges linking the processes.
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Description as Baltisphaeridium downiei:
Sarjeant, 1960, p. 138:
Diagnosis:
A species of Baltisphaeridium having a spheroidal to ovoidal shell densely covered by very short spines, knobbed or briefly bifurcate, sometimes connected by low ridges on the shell surface. The spines are in number such that 70 to 90 are seen around the shell periphery: their length is of the order of one-thirtieth the longest shell diameter.
Dimensions:
Type specimen: overall long diameter 50 µm, short diameter 45 µm (slightly damaged). Spines 1 to 1.5 µm in length. Range: overall diameters 32 to 50 µm.
Affinities: (p. 139):
Baltisphaeridium downiei differs from Baltisphaeridium fimbriatum (White, 1842) of the Cretaceous of England, and from Baltisphaeridium cf. fimbriatum (White) Sarjeant, 1960, in the relative length of its processes, around one-thirtieth instead of one-tenth the shell diameter.