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Rosswangia holotabulatum
Rosswangia holotabulatum (Davies, 1983, p.14–15, pl.1, figs.9–19; text-fig.7) Below, 1987b, p.30. Emendation: Below, 1987b, p.30, as Rosswangia holotabulata
Originally Dapcodinium, subsequently (and now) Rosswangia.
Holotype: Davies, 1983, pl.1, figs.9-11
Locus typicus: Savik Formation, District of Franklin, Northwest Territories, Canada
Stratum typicum: Toarcian-Bathonian
Translation Below, 1987: LPP
Original diagnosis: Davies, 1983, p. 15: Dapcodinium holotabulatum
A species of Dapcodinium with coarsely granulate surface. Sutures represented by lines of granules or spines. Small apical horn sometimes present. Cingulum of variable width. Tabulation: 4", 4a, 7", 7c, 6""", 2p, 1"""", 3s, 1pv. Archeopyle: (4A)+41+7P?a. Size: length - 45(48)55 µm; breadth - 37(43)55 µm.
Original description: Davies, 1983, p. 15: Dapcodinium holotabulatum
Proximate dinoflagellate cyst, almost spherical to slightly elongate. Short apical horn occasionally present; epicyst usually ruptured. Surface coarsely granulate. Sutures formed by densely aligned granules (less than 0.5 µm) with rare spines occasionally coalescing to form low ridges, up to 1 µm high.
Emended Diagnosis: Below, 1987, p.30-32
Vesicle/plate arrangement on amphiesma PR, 4", 4a, 7"", 7c, 6""", 2"""", as, FM subdivided into periflagellar platelets, ls, rs, ps; pentagonal 1"""" and haxagonal 2"""" partiform; omegaform ps very large. Growth of thecal plates peridinoidal. Cyst proximate, acavate, ovaloidal, equatorial section circular or slightly oval, epicyst shorter than hypocyst, apically rounded, indistinctly acuminate or with short apical horn, antapex rounded or asymmetrical with dextral antpical bulge, maximal diameter at the anterior cingular margin; wall rigid, pedium thin, luxuria spongy/prismatic with small affixed granules, ornamentation consisting of short gemmae and tubercles in peniareate rows and intraareate groups, low finate ridges divide the cyst surface into areae; paratabulation formula PR, 5", 4a, 7"", 7c, 6""", 2"""", as, FM, ls, rs, ps; PR usually undifferentiated or cop in the form of a horseshoe-shaped ring mounted on the apical tip and surrounded by an annular pop; 5 apicals, steno V 1" (VVL), VII 2" (L), linteloid 3" (D), VI 4" (VR) and V 5" (VVR); 4 anterior intercalaries, caroidal 1a (DL), fastigiate VI 2a (DDL), inverse-camerate 3a (DDR) and 4a (RDR); 7 precingulars, anteriorly geniculate V-nE 1""(VL), V-nE 2"" (LDL), V-nE 3"" (DDL), V-nE 4"" (D), V-nE 5"" (DR), V-nE 6"" (RVR) and V-nE 7"" (VVR); cingulum broad, level, laevigate, heptaareate, lati 1c-6c, iso-fastigiate 7c; 6 postcingulars, posteriorly linear V-nE 1""" (VVL), IV-nE 2""" (VL), IV-nE 4""" (D), IV-nE 5""" (RDR) and V-nE 6""" (VR), posteriorly geniculate V-nE 3""" (DL); 2 antapicals partiform, V 1"""" (VL and VI 2"""" (R); sulcus partite, weakly indented on the hypocyst, steno as, small rs and ls, large omegaform ps bulging somewhat into 2""""; archaeopyle apical/anterior intercalary, PR+ 1"+2"+3"+4"+5"+1a+2a+3a+4a+1""+2""+3""+4""+5""+ 6""+7""; operculum foederate, secate, general opercular formula PR+1"+2"+3"+4"+5"+ 1a+ 2a+3a+4a)(s).
Affinities:
Davies, 1983, p. 15: Dapcodinium holotabulatum
D. semitabulatum differs from D. holotabulatum by its incomplete tabulation, finer ornament and smaller size. D. ornatum differs in its smaller size and in that the sutures are marked by pandasutural zones.
Originally Dapcodinium, subsequently (and now) Rosswangia.
Holotype: Davies, 1983, pl.1, figs.9-11
Locus typicus: Savik Formation, District of Franklin, Northwest Territories, Canada
Stratum typicum: Toarcian-Bathonian
Translation Below, 1987: LPP
Original diagnosis: Davies, 1983, p. 15: Dapcodinium holotabulatum
A species of Dapcodinium with coarsely granulate surface. Sutures represented by lines of granules or spines. Small apical horn sometimes present. Cingulum of variable width. Tabulation: 4", 4a, 7", 7c, 6""", 2p, 1"""", 3s, 1pv. Archeopyle: (4A)+41+7P?a. Size: length - 45(48)55 µm; breadth - 37(43)55 µm.
Original description: Davies, 1983, p. 15: Dapcodinium holotabulatum
Proximate dinoflagellate cyst, almost spherical to slightly elongate. Short apical horn occasionally present; epicyst usually ruptured. Surface coarsely granulate. Sutures formed by densely aligned granules (less than 0.5 µm) with rare spines occasionally coalescing to form low ridges, up to 1 µm high.
Emended Diagnosis: Below, 1987, p.30-32
Vesicle/plate arrangement on amphiesma PR, 4", 4a, 7"", 7c, 6""", 2"""", as, FM subdivided into periflagellar platelets, ls, rs, ps; pentagonal 1"""" and haxagonal 2"""" partiform; omegaform ps very large. Growth of thecal plates peridinoidal. Cyst proximate, acavate, ovaloidal, equatorial section circular or slightly oval, epicyst shorter than hypocyst, apically rounded, indistinctly acuminate or with short apical horn, antapex rounded or asymmetrical with dextral antpical bulge, maximal diameter at the anterior cingular margin; wall rigid, pedium thin, luxuria spongy/prismatic with small affixed granules, ornamentation consisting of short gemmae and tubercles in peniareate rows and intraareate groups, low finate ridges divide the cyst surface into areae; paratabulation formula PR, 5", 4a, 7"", 7c, 6""", 2"""", as, FM, ls, rs, ps; PR usually undifferentiated or cop in the form of a horseshoe-shaped ring mounted on the apical tip and surrounded by an annular pop; 5 apicals, steno V 1" (VVL), VII 2" (L), linteloid 3" (D), VI 4" (VR) and V 5" (VVR); 4 anterior intercalaries, caroidal 1a (DL), fastigiate VI 2a (DDL), inverse-camerate 3a (DDR) and 4a (RDR); 7 precingulars, anteriorly geniculate V-nE 1""(VL), V-nE 2"" (LDL), V-nE 3"" (DDL), V-nE 4"" (D), V-nE 5"" (DR), V-nE 6"" (RVR) and V-nE 7"" (VVR); cingulum broad, level, laevigate, heptaareate, lati 1c-6c, iso-fastigiate 7c; 6 postcingulars, posteriorly linear V-nE 1""" (VVL), IV-nE 2""" (VL), IV-nE 4""" (D), IV-nE 5""" (RDR) and V-nE 6""" (VR), posteriorly geniculate V-nE 3""" (DL); 2 antapicals partiform, V 1"""" (VL and VI 2"""" (R); sulcus partite, weakly indented on the hypocyst, steno as, small rs and ls, large omegaform ps bulging somewhat into 2""""; archaeopyle apical/anterior intercalary, PR+ 1"+2"+3"+4"+5"+1a+2a+3a+4a+1""+2""+3""+4""+5""+ 6""+7""; operculum foederate, secate, general opercular formula PR+1"+2"+3"+4"+5"+ 1a+ 2a+3a+4a)(s).
Affinities:
Davies, 1983, p. 15: Dapcodinium holotabulatum
D. semitabulatum differs from D. holotabulatum by its incomplete tabulation, finer ornament and smaller size. D. ornatum differs in its smaller size and in that the sutures are marked by pandasutural zones.