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Microdinium horridum
From Fensome et al., 2019:
Microdinium? horridum (Below, 1987b, p.49–50, pl.17, figs.1–6; text-figs.11a–h) Lentin and Williams, 1989, p.245. Holotype: Below, 1987b, pl.17, figs.1–6; Fensome et al., 1993a, figs.1–4 — p.1229. Originally Phanerodinium, subsequently (and now) Microdinium?. Lentin and Williams (1993, p.426) retained this species in Microdinium. Questionable assignment: Lentin and Williams (1989, p.245). Age: middle Albian–early Cenomanian.
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Locus typicus: Wissant, Boulonnais, France
Stratum typicum: Middle Albian
Original description: Below 1987b, p. 49-50: Phanerodinium horridum
Vesicle/plate arrangement on amphiesma cop, pop, cap, 4', 4a, 7'', 7c, 6''', 2'''', as, FM subdivided into peri- flagellar platelets, ls, rs, ps; pentagonal 1'''' and hexagonal 2'''' partiform; omegaform ps very large; adelopore on suture 1'/4'. Growth of thecal plates gonyaulacoidal. Cyst proximochorate, acavate, polyhedral, extremely lenticular with parallel dorsal and ventral sides, epicyst very small, flattened-tholiform, hypocyst 4-6 times as long, prismatic and antapically roof-shaped, maximal diameter at the posterior cingular margin; size small; wall composed of thin pedium and fibrose luxuria fused distally into a tegillum connected by fibers wich are very low on intraareate spaces and sometimes reduced to granules or absent, but long on the limbi, bridging the entire finate pericoel; surface of tegillum scabrate to levigate; on the fines, the tegillum forms very low ridges between areae, but between large areae it forms carinate, distally glabrous ribs produced gonally into high, broad-based, distally acuminate spines; paratabulation cop, pop, cap, 4', 4a, 7'', 7c, 6''', 2'''', as, FM, ls, rs, ps; cop very small, circular, surrounded by annular pop, small planate cap (V); very small apicals, steno VII 1' (V), VIII 2' (L), VIII 3' (R), steno V 4' (VVR) with porichnion on finis 4'/1'; 4 very small anterior intercalaries, caroidal 1a (DL), fastigiate 2a (D), deltaform inverse-camerate 3a (DR), V 4a (RVR); 7 precingulars, anteriorly geniculate V-nE 1'' (VVL), V-nE 2'' (L), V-nE 3'' (DDL), V-nE 4'' (DDR), V-nE 5'' (R) and V-nE 6'' (VR), small anteriorly geniculate V-nE 7'' (VVR); finis 3''/4'' often dorsal; cingulum planispiral, beginning and end of cingulum forming a shallow v-shaped configuration with the sulcus, shallowly indented or level, heptapartite, lati 1c to 6c, iso fastigiate 7c; 6 very large steno postcingulars, posterior linear V-nE 1''' (VVL) and IV-nE 2''' (VL), posteriorly geniculate V-nE 3''' (DL), posteriorly linear IV-nE 4''' (DDR), IV-nE 5''' and V-nE 6''' (VR); 2 quasi-planar antapicals descending laterally on each side of the pole, V 1'''' (L), VI 2'''' R; sulcus level or lightly indented on the hypocyst, partite, small VI as, small oval FM subdivided into several very small eareae, small V ls, small V rs, large deltaform fastigiate ps; archaeopyle 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.
Dimensions of holotype: Length 46 µm, Breath 47 µm, Thickness 20 µm.
Microdinium? horridum (Below, 1987b, p.49–50, pl.17, figs.1–6; text-figs.11a–h) Lentin and Williams, 1989, p.245. Holotype: Below, 1987b, pl.17, figs.1–6; Fensome et al., 1993a, figs.1–4 — p.1229. Originally Phanerodinium, subsequently (and now) Microdinium?. Lentin and Williams (1993, p.426) retained this species in Microdinium. Questionable assignment: Lentin and Williams (1989, p.245). Age: middle Albian–early Cenomanian.
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Locus typicus: Wissant, Boulonnais, France
Stratum typicum: Middle Albian
Original description: Below 1987b, p. 49-50: Phanerodinium horridum
Vesicle/plate arrangement on amphiesma cop, pop, cap, 4', 4a, 7'', 7c, 6''', 2'''', as, FM subdivided into peri- flagellar platelets, ls, rs, ps; pentagonal 1'''' and hexagonal 2'''' partiform; omegaform ps very large; adelopore on suture 1'/4'. Growth of thecal plates gonyaulacoidal. Cyst proximochorate, acavate, polyhedral, extremely lenticular with parallel dorsal and ventral sides, epicyst very small, flattened-tholiform, hypocyst 4-6 times as long, prismatic and antapically roof-shaped, maximal diameter at the posterior cingular margin; size small; wall composed of thin pedium and fibrose luxuria fused distally into a tegillum connected by fibers wich are very low on intraareate spaces and sometimes reduced to granules or absent, but long on the limbi, bridging the entire finate pericoel; surface of tegillum scabrate to levigate; on the fines, the tegillum forms very low ridges between areae, but between large areae it forms carinate, distally glabrous ribs produced gonally into high, broad-based, distally acuminate spines; paratabulation cop, pop, cap, 4', 4a, 7'', 7c, 6''', 2'''', as, FM, ls, rs, ps; cop very small, circular, surrounded by annular pop, small planate cap (V); very small apicals, steno VII 1' (V), VIII 2' (L), VIII 3' (R), steno V 4' (VVR) with porichnion on finis 4'/1'; 4 very small anterior intercalaries, caroidal 1a (DL), fastigiate 2a (D), deltaform inverse-camerate 3a (DR), V 4a (RVR); 7 precingulars, anteriorly geniculate V-nE 1'' (VVL), V-nE 2'' (L), V-nE 3'' (DDL), V-nE 4'' (DDR), V-nE 5'' (R) and V-nE 6'' (VR), small anteriorly geniculate V-nE 7'' (VVR); finis 3''/4'' often dorsal; cingulum planispiral, beginning and end of cingulum forming a shallow v-shaped configuration with the sulcus, shallowly indented or level, heptapartite, lati 1c to 6c, iso fastigiate 7c; 6 very large steno postcingulars, posterior linear V-nE 1''' (VVL) and IV-nE 2''' (VL), posteriorly geniculate V-nE 3''' (DL), posteriorly linear IV-nE 4''' (DDR), IV-nE 5''' and V-nE 6''' (VR); 2 quasi-planar antapicals descending laterally on each side of the pole, V 1'''' (L), VI 2'''' R; sulcus level or lightly indented on the hypocyst, partite, small VI as, small oval FM subdivided into several very small eareae, small V ls, small V rs, large deltaform fastigiate ps; archaeopyle 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.
Dimensions of holotype: Length 46 µm, Breath 47 µm, Thickness 20 µm.