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Microdinium carinatum

Microdinium carinatum (Below, 1987) Lentin and Williams, 1989

Originally Phanerodinium, subsequently (and now) Microdinium.
Holotype: Below, 1987, pl.10, figs.1-5
Locus typicus: Pit IV, Misburg, Germany
Stratum typicum: Late Campanian
Translation Below, 1987: Fensome et al., 1993

Original Description: Below, 1987, p.41: Phanerodinium carinatum
Arrangement of vesicles/plates on the dinoflagellate amphiesma cop, pop, cap, 4", 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; adelopore on suture 1"/4"; growth of plates gonyaulacoid.
Cyst form proximate, acavate-finicavate, spheroidal, slightly ovaloidal, hypocyst twice as long as epicyst, equatorial section circular, maximum diameter at the posterior cingular margin; size small; wall composed of thin pedium and rigid luxuria fused distally to form a tegillum, surface glabrous to shagreenate; numerous pits or perforations diffusely intraareate or aligned congruently to the area margin reflect trichocyst pores; tegillum rising from a broad, finate base to form hollow distal carinae, tapering to smooth, sharp edges; the carinae, symmetrical or leaning in one direction, directly imitate the overlapping of thecal plates; areation formula XPR/COP, pop, cap, X"/4", Xa/4a, 7", 7c, 6""", 2"""", as, FM, ls, rs, ps; PR, apicals, and anterior intercalaries reflected only rudimentarily, or cop very small, circular, surrounded by an annular pop, small planate cap (V); 4 small apicals, steno VII 1" (V), VIII 2" (L),VIII 3" (R), steno V 4" (VVR), porichnion on finis 4"/1"; 4 small anterior intercalaries, small caroidal 1a (DL), fastigiate 2a (D), deltaform inverse-camerate 3a (DR),V 4a (RVR); 7 precingulars, anteriorly geniculate V-nE 1" (VVL), anteriorly geniculate V-nE 2" (L), anteriorly geniculate V-nE 3" (DDL), anteriorly geniculate V-nE 4" (DDR), finis 3"/4" characteristically somewhat dorsal, anteriorly geniculate V-nE 5" (R), anteriorly geniculate V-nE 6" (VR), small anteriorly geniculate V-nE 7" (VVR); cingulum planispiral or very weakly helicoid laevorotatory, level or only slightly indented, heptapartite, lati 1c to 6c, isofastigiate 7c; 6 postcingulars, posteriorly linear V-nE 1""" (VVL), posteriorly linear IV-nE 2""" (VL), posteriorly geniculate V-nE 3""" (DL), posteriorly linear IV-nE 4""" (DDR), posteriorly linear IV-nE 5""" (R), posteriorly linear V-nE 6""" (VR); 2 antapicals partiform, V 1"""" descending towards VL, VI 2"""" towards R; sulcus slightly indented on the hypocyst, partite, small VI as, small oval FM subdivided into several small areae, small V ls, small V rs, large omegaform VI ps; archeopyle apical/anterior intercalary, PR+1"+ 2" + 3" + 4 + 1a + 2a + 3a + 4a; operculum foederate, adnate, general opercular formula (PR+1" + 2" + 3" + 4" + 1a + 2a + 3a + 4a)a.
Size: Holotype: length 36 Ám, breadth 33 Ám, thickness 33 Ám.
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