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Dapcodinium polyedricum
Dapcodinium polyedricum Below, 1987
Holotype: Below, 1987, pl.23, fig.1, 4-5
Locus typicus: Athyrid Limestone, East Cape Bogal, Misol, Moluccas, Indonesia
Stratum typicum: Norian
Translation: Bureau of Translation, Secretary of State Canada, 1988, p. 370-373
Original description: Below, 1987, p. 144-149
Description: Arrangement of vesicles/plates on the dinoflagellate amphiesma PR,, 5", 4a, 7"", 8c, 8"""-7"""-6""", 3"""", as, y, z, ps.
Cystic habit proximate, acavate, polyhedral, apically somewhat acuminate, antapically rounded or flattened, dorsoventrally somewhat compressed or circular, size small; wall composed of thin pedium, surface smooth, subdivided into areae by low luxuriate ribs ranging from bulges to septa; areation PR, 5", 4a, 7"", 8c, 8"""-6""", 3"""", as, y, z, ps; PR pentagonal;
- 5 Apicals; VI 1" (V), quasifastigiate 2" (VL), VII 3" (DL), omegaform linteloid 4" (DR), VI 5" (VR); caroidal 1a (L), caroidal 2a (DL), V 3a (DDR), caroidal 4a (R);
- 7 precingulars, anteriorly geniculate V-nE 1"" (VVL), anteriorly geniculate VI-nE 2"" (LVL), anteriorly bigeniculate VI-nE 3"" (DL), anteriorly geniculate V-nE 4"" (D), anteriorly bigeniculate VI-nE 5"" (DR), anteriorly geniculate V-nE 6"" (VR), anteriorly geniculate V-nE 7"" (VVR);
- cingulum equatorial, helicoid laevorotatory, comprising 8 areae of equal size, 1c and 8c non-finate towards the sulcus;
- generally 7 postcingulars, posteriorly linear V-nE 1""" (VVL), posteriorly linear IV-nE 2""" (VL), posteriorly geniculate V-nE 3""" (L), posteriorly linear IV nE 4""" (DDL), posteriorly geniculate V-nE 5""" (DDR), posteriorly linear IV-nE 6""" (R), posteriorly linear V-nE 7""" (VR), VII 1"""" (VL), V 2"""" (DDL), VI 3"""" (R); or hypocystal variant with 8 postcingulars, posteriorly linear V-nE 1""", posteriorly linear IV-nE 2""", posteriorly geniculate V-nE 3""", posteriorly linear IV-nE 4""", posteriorly linear IV-nE 5""", posteriorly geniculate V-nE 6""", posteriorly linear IVnE 7""", posteriorly geniculate VI-nE 8""", VII 1"""" (VL), VI 2"""" (DDL), VI 3"""" (R); or hypocystal variant with six postcingulars, posteriorly linear V-nE 1""", posteriorly linear IV-nE 2""", posteriorly geniculate V-nE 3""", posteriorly geniculate V-nE 4""", posteriorly linear IV-nE 5""", posteriorly geniculate V-nE 6""", VII 1"""", IV 2"""", VI 3""""; sulcus slanting dextral to the posterior, broad, nonareate or with traces of areation with a small V-nE as, antero-posteriorly superposed y, z, and sigmoid IV ps bending into 3""""; - archeopyle apical and anterior intercalary, 3" + 4" + 2a + 3a; operculum ?solvate, ?foederate, secate, operular formula 3"s + 4"s + 2as + 3as or pylome-like.
Dimensions: Holotype: length 31 Ám, breadth 25 Ám, thickness 25 Ám.
Remarks: Excepting the sulcus and mediodorsal regions, the areation is well developed. The sulcus is distinctly bounded from adsulcal areas, but its own subdivision into the column of areae as, y, z, and ps is only indicated (Plate 23, Fig. 17). 3", 4", 2a and 3a usually form a single large, nonareate mediodorsal surface. Only short extensions of finis 2a/3a and finis 3"/4" enter this sector, starting from points 2a.3a.4"" and PR, respectively. These fines do not extend towards each other, but deviate respectively sinistrad and dextrad from an imaginary straight line connecting PR with point 2a.3a.4"". We should therefore assume also a very short finis 3""/3a, so that the four mediodorsal areae do not meet at one point, but 2a and 4" are separated by the combined area 3a/3" - as in fact is evidenced by specimen s2-1477(KO)10/9. Another infrequent occurrence is short, finely ornamented fines starting at points 2a.3".3"" and 3a.4".5"" and oriented towards the apex. These two points can always be recognized as angles of the anterior fines of 3"" and 5"" just next to the beginning of fines 1a/3" and 4a/4", respectively (Plate 23, Fig. 12 and 13), so that they mark the abutment of three areae. The reconstruction of the mediodorsal surface shows that 3" and 4" extend posteriorly to the precingulars, thus obviously isolating 1a and 4a from the dorsal group of anterior intercalaries 2a and 3a. This separation is eliminated, e.g., in the later Dapcodinium ovale n. sp., in which all anterior intercalaries are in contact with each other.
The positions of cingular and adcingular areae vary individually to a minor degree, as partical area series rotate slightly in relation to each other. This somewhat alters the relative position of respective areae, as shown by examples in Figure 76. In the diagrams, to facilitate comparison, the positions of the postcingular areae are defined as constant. The positions of the fines of cingular and precingular areae are shown in relation to the fines of the postcingulars. The geometry of the adcingular areae deviates accordingly from the typical arrangement (Figure 75). Overlapping of thecal plates is extensively reflected on the cyst. For example, if thecal plate 3"" is overlapped by 4"" this can be seen from the cyst, because fines 3""/4"" and 4""/2"" project slightly outward towards the reflected overlapped 3"" and 2"" or, at a triple contact point, e.g., 3"".4"".c, finis 3""/4"" turns with the same thickness as finis 4""/4c, whereas finis 3""/4c thins out on the side facing 4"" and abuts the turning of finis 3""/4""/4c at a distinct angle (Plate 23, fig. 15 and 16; Plate 26e). The material from the Moluccas reveals the overlapping shown in Figure 74a and b.
Holotype: Below, 1987, pl.23, fig.1, 4-5
Locus typicus: Athyrid Limestone, East Cape Bogal, Misol, Moluccas, Indonesia
Stratum typicum: Norian
Translation: Bureau of Translation, Secretary of State Canada, 1988, p. 370-373
Original description: Below, 1987, p. 144-149
Description: Arrangement of vesicles/plates on the dinoflagellate amphiesma PR,, 5", 4a, 7"", 8c, 8"""-7"""-6""", 3"""", as, y, z, ps.
Cystic habit proximate, acavate, polyhedral, apically somewhat acuminate, antapically rounded or flattened, dorsoventrally somewhat compressed or circular, size small; wall composed of thin pedium, surface smooth, subdivided into areae by low luxuriate ribs ranging from bulges to septa; areation PR, 5", 4a, 7"", 8c, 8"""-6""", 3"""", as, y, z, ps; PR pentagonal;
- 5 Apicals; VI 1" (V), quasifastigiate 2" (VL), VII 3" (DL), omegaform linteloid 4" (DR), VI 5" (VR); caroidal 1a (L), caroidal 2a (DL), V 3a (DDR), caroidal 4a (R);
- 7 precingulars, anteriorly geniculate V-nE 1"" (VVL), anteriorly geniculate VI-nE 2"" (LVL), anteriorly bigeniculate VI-nE 3"" (DL), anteriorly geniculate V-nE 4"" (D), anteriorly bigeniculate VI-nE 5"" (DR), anteriorly geniculate V-nE 6"" (VR), anteriorly geniculate V-nE 7"" (VVR);
- cingulum equatorial, helicoid laevorotatory, comprising 8 areae of equal size, 1c and 8c non-finate towards the sulcus;
- generally 7 postcingulars, posteriorly linear V-nE 1""" (VVL), posteriorly linear IV-nE 2""" (VL), posteriorly geniculate V-nE 3""" (L), posteriorly linear IV nE 4""" (DDL), posteriorly geniculate V-nE 5""" (DDR), posteriorly linear IV-nE 6""" (R), posteriorly linear V-nE 7""" (VR), VII 1"""" (VL), V 2"""" (DDL), VI 3"""" (R); or hypocystal variant with 8 postcingulars, posteriorly linear V-nE 1""", posteriorly linear IV-nE 2""", posteriorly geniculate V-nE 3""", posteriorly linear IV-nE 4""", posteriorly linear IV-nE 5""", posteriorly geniculate V-nE 6""", posteriorly linear IVnE 7""", posteriorly geniculate VI-nE 8""", VII 1"""" (VL), VI 2"""" (DDL), VI 3"""" (R); or hypocystal variant with six postcingulars, posteriorly linear V-nE 1""", posteriorly linear IV-nE 2""", posteriorly geniculate V-nE 3""", posteriorly geniculate V-nE 4""", posteriorly linear IV-nE 5""", posteriorly geniculate V-nE 6""", VII 1"""", IV 2"""", VI 3""""; sulcus slanting dextral to the posterior, broad, nonareate or with traces of areation with a small V-nE as, antero-posteriorly superposed y, z, and sigmoid IV ps bending into 3""""; - archeopyle apical and anterior intercalary, 3" + 4" + 2a + 3a; operculum ?solvate, ?foederate, secate, operular formula 3"s + 4"s + 2as + 3as or pylome-like.
Dimensions: Holotype: length 31 Ám, breadth 25 Ám, thickness 25 Ám.
Remarks: Excepting the sulcus and mediodorsal regions, the areation is well developed. The sulcus is distinctly bounded from adsulcal areas, but its own subdivision into the column of areae as, y, z, and ps is only indicated (Plate 23, Fig. 17). 3", 4", 2a and 3a usually form a single large, nonareate mediodorsal surface. Only short extensions of finis 2a/3a and finis 3"/4" enter this sector, starting from points 2a.3a.4"" and PR, respectively. These fines do not extend towards each other, but deviate respectively sinistrad and dextrad from an imaginary straight line connecting PR with point 2a.3a.4"". We should therefore assume also a very short finis 3""/3a, so that the four mediodorsal areae do not meet at one point, but 2a and 4" are separated by the combined area 3a/3" - as in fact is evidenced by specimen s2-1477(KO)10/9. Another infrequent occurrence is short, finely ornamented fines starting at points 2a.3".3"" and 3a.4".5"" and oriented towards the apex. These two points can always be recognized as angles of the anterior fines of 3"" and 5"" just next to the beginning of fines 1a/3" and 4a/4", respectively (Plate 23, Fig. 12 and 13), so that they mark the abutment of three areae. The reconstruction of the mediodorsal surface shows that 3" and 4" extend posteriorly to the precingulars, thus obviously isolating 1a and 4a from the dorsal group of anterior intercalaries 2a and 3a. This separation is eliminated, e.g., in the later Dapcodinium ovale n. sp., in which all anterior intercalaries are in contact with each other.
The positions of cingular and adcingular areae vary individually to a minor degree, as partical area series rotate slightly in relation to each other. This somewhat alters the relative position of respective areae, as shown by examples in Figure 76. In the diagrams, to facilitate comparison, the positions of the postcingular areae are defined as constant. The positions of the fines of cingular and precingular areae are shown in relation to the fines of the postcingulars. The geometry of the adcingular areae deviates accordingly from the typical arrangement (Figure 75). Overlapping of thecal plates is extensively reflected on the cyst. For example, if thecal plate 3"" is overlapped by 4"" this can be seen from the cyst, because fines 3""/4"" and 4""/2"" project slightly outward towards the reflected overlapped 3"" and 2"" or, at a triple contact point, e.g., 3"".4"".c, finis 3""/4"" turns with the same thickness as finis 4""/4c, whereas finis 3""/4c thins out on the side facing 4"" and abuts the turning of finis 3""/4""/4c at a distinct angle (Plate 23, fig. 15 and 16; Plate 26e). The material from the Moluccas reveals the overlapping shown in Figure 74a and b.