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Eisenackia circumtabulata
Eisenackia circumtabulata Drugg, 1967
NOW Alisocysta. Originally Eisenackia, subsequently Hystrichokolpoma, thirdly (and now) Alisocysta, fourthly Agerasphaera (generic name illegitimate). Quattrocchio and Sarjeant (2003, p.146) retained this species in Eisenackia, but Fensome et al. (in press) returned it to Alisocysta.
Taxonomic junior synonym: Hystrichokolpoma mentitum, according to Schumacker-Lambry (1978, p.42) — however, Lentin and Williams (1981, p.135) retained Hystrichokolpoma mentitum.
Holotype: Drugg, 1967, pl.1, fig.12
Paratype: Drugg, 1967
Locus typicus: Escarpado Canyon, California, U.S.A.
Stratum typicum: Danian
Original description: Drugg, W. 1967, p.15
Diagnosis: Test ellipsoidal in outline, somewhat compressed. Wall thick, very finely punctate on some specimens. The plates are deliniated by low membranous walls. The tabulation is identical to that of Eisenackia crassitabulata Deflandre and Cookson 1955. The test opens by means of an apical operculum. Size range, 36 to 47 µm wide, 37 to 47 µm high (six specimens).
Affinities:
Drugg, W. 1967, p. 15: This species differs from Eisenackia crassitabulata in that the plates are marked by raised walls, the interiors of which are not filled with a thick-walled mesh.
NOW Alisocysta. Originally Eisenackia, subsequently Hystrichokolpoma, thirdly (and now) Alisocysta, fourthly Agerasphaera (generic name illegitimate). Quattrocchio and Sarjeant (2003, p.146) retained this species in Eisenackia, but Fensome et al. (in press) returned it to Alisocysta.
Taxonomic junior synonym: Hystrichokolpoma mentitum, according to Schumacker-Lambry (1978, p.42) — however, Lentin and Williams (1981, p.135) retained Hystrichokolpoma mentitum.
Holotype: Drugg, 1967, pl.1, fig.12
Paratype: Drugg, 1967
Locus typicus: Escarpado Canyon, California, U.S.A.
Stratum typicum: Danian
Original description: Drugg, W. 1967, p.15
Diagnosis: Test ellipsoidal in outline, somewhat compressed. Wall thick, very finely punctate on some specimens. The plates are deliniated by low membranous walls. The tabulation is identical to that of Eisenackia crassitabulata Deflandre and Cookson 1955. The test opens by means of an apical operculum. Size range, 36 to 47 µm wide, 37 to 47 µm high (six specimens).
Affinities:
Drugg, W. 1967, p. 15: This species differs from Eisenackia crassitabulata in that the plates are marked by raised walls, the interiors of which are not filled with a thick-walled mesh.