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Phanerodinium dentatum
Phanerodinium dentatum (Vozzhennikova, 1967); emend. Below, 1987
Now Microdinium?. Originally Microdinium, subsequently (and now) Microdinium?, thirdly Phanerodinium. Lentin and Williams, 1989 retained the species in Microdinium Cookson and Eisenack, 1960.
Holotype: Vozzhennikova, 1967, pl.38, fig.2a-e; Lentin and Vozzhennikova, 1990, pl.12, figs. 5-7; text-fig.59
Locus typicus: Smolensk region, USSR
Stratum typicum: Late Cretaceous
Translation Vozzhennikova, 1967: Lee in Sarjeant (ed.) 1971, p. 144
Translation Below, 1987: LPP
Original diagnosis:
Vozzhennikova 1967, p. 94-95: Microdinium dentatum Theca spherical or ovoid. Epitheca smaller than hypotheca. Arrangement of plates as in Microdinium ornatum. Plates and margins of transverse furrow bounded by light coloured toothed crest. Theca pale yellow in colour, the surface granular.
Dimensions: length:
32.4-40.5 µm; breadth: 32.4-37 µm; width of transverse furrow: 5.4 µm; width of crest: 4-5 µm.
Emended description: Below, 1987, p.45-46
Vesicle/plate arrangement on amphiesma pop, cop, cap, 4", 4a, 7"", 7c, 6""", 2"""", as, FM subdivided into periflagellar platelets, ls, rs, ps; pentagonal 1"""" and hexagonal 2"""" partiform; omegaform ps very large; adelopore on suture 1"/4". Growth of plates gonyaulacoidal. Cyst proximate-proximochorate, acavate-finicavate, ovaloidal-polyhedral with tholiform epicyst and larger tentiriate hypocyst, equatorial section circular to slightly oval; size small; wall composed of thin pedium and spongy luxuria which closes distally into a tegillum, surface glabrous to scabrate, each area completely surrounded by a basally peniareate, distally denticulate septum; the septa of neighbouring areae converge towards each other and their distal teeth interlock exactly at the finis, forming an apparently homogenous, finate, carinate, distally denticulate rib; paratabulation X PR/cop, pop, cap, X"/4", Xa/4a, 7"", 7c, 6""", 2"""", as, FM, ls, rs, ps; PR undifferentiated or cop very small, circular, surrounded by an annular pop, small planate cap (V); 4 very small, often rudimentary reflected apicals, steno V 1" (VVR), VIII 2" (L), VIII 3" (R), steno V 4" (VVR); 4 very small anterior intercalaries, their position only poorly defined by finate rows of granules, or caroidal 1a (DL), fastigiate 2a (D), deltaform inverse-camerate 3a (DR), V 4a (RVR); 7 precingulars, anteriorly geniculate V-nE 1"" (L), 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"" approximately dorsal; cingulum weakly helicoid, indented, heptapartite, lati 1c-6c, iso fastigiate 7c; 6 postcingulars, posteriorly 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""" (R) and V-nE 6""" (VR); 2 antapicals partiform, V 1"""" descending towards VL, VI 2"""" towards R; sulcus lightly indented on the hypocyst, partite, small VI as, small oval FM subdivided into very small areae, small V ls, small V rs, large omegaform VI 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.
Affinities:
Vozzhennikova 1967, p. 94-95: Microdinium dentatum differs from related forms in having a toothed crest on the boundaries of the plates and on the margin of the transverse furrow. Note: Some members of this species have a different shape of theca: in some it is ovoid, in others spherical. This is the basis for the separation of two forms: f. dentatum and f. sphaericum.
Below 1987, p.46: Phanerodinium dentatum, is very similar to P. setosum (Sarjeant 1966), but latter forms finate ridges bearing spines and spinules.
Now Microdinium?. Originally Microdinium, subsequently (and now) Microdinium?, thirdly Phanerodinium. Lentin and Williams, 1989 retained the species in Microdinium Cookson and Eisenack, 1960.
Holotype: Vozzhennikova, 1967, pl.38, fig.2a-e; Lentin and Vozzhennikova, 1990, pl.12, figs. 5-7; text-fig.59
Locus typicus: Smolensk region, USSR
Stratum typicum: Late Cretaceous
Translation Vozzhennikova, 1967: Lee in Sarjeant (ed.) 1971, p. 144
Translation Below, 1987: LPP
Original diagnosis:
Vozzhennikova 1967, p. 94-95: Microdinium dentatum Theca spherical or ovoid. Epitheca smaller than hypotheca. Arrangement of plates as in Microdinium ornatum. Plates and margins of transverse furrow bounded by light coloured toothed crest. Theca pale yellow in colour, the surface granular.
Dimensions: length:
32.4-40.5 µm; breadth: 32.4-37 µm; width of transverse furrow: 5.4 µm; width of crest: 4-5 µm.
Emended description: Below, 1987, p.45-46
Vesicle/plate arrangement on amphiesma pop, cop, cap, 4", 4a, 7"", 7c, 6""", 2"""", as, FM subdivided into periflagellar platelets, ls, rs, ps; pentagonal 1"""" and hexagonal 2"""" partiform; omegaform ps very large; adelopore on suture 1"/4". Growth of plates gonyaulacoidal. Cyst proximate-proximochorate, acavate-finicavate, ovaloidal-polyhedral with tholiform epicyst and larger tentiriate hypocyst, equatorial section circular to slightly oval; size small; wall composed of thin pedium and spongy luxuria which closes distally into a tegillum, surface glabrous to scabrate, each area completely surrounded by a basally peniareate, distally denticulate septum; the septa of neighbouring areae converge towards each other and their distal teeth interlock exactly at the finis, forming an apparently homogenous, finate, carinate, distally denticulate rib; paratabulation X PR/cop, pop, cap, X"/4", Xa/4a, 7"", 7c, 6""", 2"""", as, FM, ls, rs, ps; PR undifferentiated or cop very small, circular, surrounded by an annular pop, small planate cap (V); 4 very small, often rudimentary reflected apicals, steno V 1" (VVR), VIII 2" (L), VIII 3" (R), steno V 4" (VVR); 4 very small anterior intercalaries, their position only poorly defined by finate rows of granules, or caroidal 1a (DL), fastigiate 2a (D), deltaform inverse-camerate 3a (DR), V 4a (RVR); 7 precingulars, anteriorly geniculate V-nE 1"" (L), 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"" approximately dorsal; cingulum weakly helicoid, indented, heptapartite, lati 1c-6c, iso fastigiate 7c; 6 postcingulars, posteriorly 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""" (R) and V-nE 6""" (VR); 2 antapicals partiform, V 1"""" descending towards VL, VI 2"""" towards R; sulcus lightly indented on the hypocyst, partite, small VI as, small oval FM subdivided into very small areae, small V ls, small V rs, large omegaform VI 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.
Affinities:
Vozzhennikova 1967, p. 94-95: Microdinium dentatum differs from related forms in having a toothed crest on the boundaries of the plates and on the margin of the transverse furrow. Note: Some members of this species have a different shape of theca: in some it is ovoid, in others spherical. This is the basis for the separation of two forms: f. dentatum and f. sphaericum.
Below 1987, p.46: Phanerodinium dentatum, is very similar to P. setosum (Sarjeant 1966), but latter forms finate ridges bearing spines and spinules.