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Mikrocysta rugosa
Mikrocysta rugosa Below, 1987
Holotype: Below, 1987, pl. 3, fig. 7-10; Fensome et al., 1993, p.1307, figs.1-2
Locus typicus: Knerten Hill near DeGeerdalen, Spitsbergen
Stratum typicum: Toarcian
Translation Below, 1987: Fensome et al., 1993
Original description: Below, 1987, p. 19
Diagnosis (annotated): Arrangement of vesicles/plates of the dinoflagellate amphiesma PR, 5", 3a- 4a, 7"", 7c, 6""", 2"""", as, Fm, subdivided into several periflagellar platelets, ls, rs, ps; pentagonal 1"""" and hexagonal 2"""" partiform; omegaform ps very large. Cyst habit proximate, acavate to holocavate, cruciform, seldom ovaloidal, epicyst transversely ellipsoidal, hypocyst transversily ellipsoidal and protuberant especially laterally and antapically, epicyst distinctly smaller than the hypocyst in height and breadth and separated from it by a broad, indented weakly helicoid laevorotatory cingulum, sulcus not reflected or only weakly indented, equatorial section of cyst lenticular to oval; size small; wall composed of thin pedium, luxuria spongy, firm, directly superposed on the pedium or separated from it by a low pericoel, surface rugulate, nonareate; areation formula NR PR, NR1", NR2", 3"arch, 4"arch, NR5", NRa, NRc/Xc, NR""", NR"""", NRs/Xs; archeopyle apical, amplificate, 3" + 4"; operculum solvate, secate, opercular formula 3"s + 4"s.
Dimensions of Holotype: Length 33 Ám, breadth 30 Ám, thickness 20 Ám.
Remarks: Because of the amplificate opercular plates, the archeopyle is nearly circular (Plate 3, Fig. 12). In contrast to Mikrocysta erugata, in which one of the two opercular pieces was occasionally found in situ, in the material of Mikrocysta granulata n. sp. at my disposal, the exit hole was always fully formed, so that evidence of a solvate or a foederate operculum could not be had. Therefore the opercular formula was inferred by analogy with Mikrocysta erugata.
Holotype: Below, 1987, pl. 3, fig. 7-10; Fensome et al., 1993, p.1307, figs.1-2
Locus typicus: Knerten Hill near DeGeerdalen, Spitsbergen
Stratum typicum: Toarcian
Translation Below, 1987: Fensome et al., 1993
Original description: Below, 1987, p. 19
Diagnosis (annotated): Arrangement of vesicles/plates of the dinoflagellate amphiesma PR, 5", 3a- 4a, 7"", 7c, 6""", 2"""", as, Fm, subdivided into several periflagellar platelets, ls, rs, ps; pentagonal 1"""" and hexagonal 2"""" partiform; omegaform ps very large. Cyst habit proximate, acavate to holocavate, cruciform, seldom ovaloidal, epicyst transversely ellipsoidal, hypocyst transversily ellipsoidal and protuberant especially laterally and antapically, epicyst distinctly smaller than the hypocyst in height and breadth and separated from it by a broad, indented weakly helicoid laevorotatory cingulum, sulcus not reflected or only weakly indented, equatorial section of cyst lenticular to oval; size small; wall composed of thin pedium, luxuria spongy, firm, directly superposed on the pedium or separated from it by a low pericoel, surface rugulate, nonareate; areation formula NR PR, NR1", NR2", 3"arch, 4"arch, NR5", NRa, NRc/Xc, NR""", NR"""", NRs/Xs; archeopyle apical, amplificate, 3" + 4"; operculum solvate, secate, opercular formula 3"s + 4"s.
Dimensions of Holotype: Length 33 Ám, breadth 30 Ám, thickness 20 Ám.
Remarks: Because of the amplificate opercular plates, the archeopyle is nearly circular (Plate 3, Fig. 12). In contrast to Mikrocysta erugata, in which one of the two opercular pieces was occasionally found in situ, in the material of Mikrocysta granulata n. sp. at my disposal, the exit hole was always fully formed, so that evidence of a solvate or a foederate operculum could not be had. Therefore the opercular formula was inferred by analogy with Mikrocysta erugata.