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Dapcodinium priscum
Dapcodinium priscum Evitt, 1961; emend. Below, 1987
The epithet was erroneously indicated as a noun in apposition in Fensome and Williams (2004).
Holotype: Evitt, 1961, pl.119, fig.1-2; text-fig.10-11
Locus typicus: Randers, Jutland, Denmark
Stratum typicum: Hettangian
Translation Below, 1987: Bureau of Translation, Secretary of State Canada, 1988, p. 378-381
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Dapcodinium priscum Evitt, 1961a, emend. Below, 1987a. According to Below (1987a, p 149)this species has a amphiesmal tabulation of PR, 5', 6a, 7", 8c, 7"’, 3"”, as, y, z, ps. It is proximate, acavate, spheroidal, epicyst and hypocyst of equal size; small; wall surface vermiculate to granulate, with very delicate low sutural crests and rows of granules, nontabulate, partly tabulate or completely tabulate. Tabulation formula: NR, PR/PR, ;5', 6a, 7", Xc, 7"’, 3"”, Xs. Archeopyle complex, comprising apicals and anterior intercalaries or pylome-like. The two cingular margins are always marked by low, but solid crests or rows of granules. PS is sigmoidal.
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Original description: Evitt, 1961, p. 996, 998
Diagnosis: Subspherical, with obtusely pointed apex; diameter 25-30 Ám. Theca less than 0.3 Ám thick, especially thin in the apical region. Sutures simple, slightly thickened. Tabulation: 4', 4a, 7'', 6g, 6''', 2p, 1''''. Plates 1-4a large and subequal, pentagonal; plates 1p and 2p large, 2p the larger; plates 1'' and 7'', 1''' and 6''' smaller than others of respective series; plate 1' asymmetrical, barely in contact with 7''. Girdle lefthanded, conspicuously wide (5-7 Ám), displaced slightly more than one girdle width. Ventral area large, chiefly on hypotheca; some boundaries of constituent plates usually visible. Rupture apparently by separation along sutures in apical region. Diameter: 25-30 Ám.
Emended description: Below 1987, p. 149
Arrangement of vesicles/plates on the dinoflagellate amphiesma PR, 5', 6a, 7'', 8c, 7'', 3'''', as, y, z, ps.
Cystic habit proximate, acavate, spheroidal, epicyst and hypocyst of equal size; size small; wall composed of thin pedium, surface vermiculate to granular with very delicate, low fineta crests and rows of granules, nonareate, partially areate, or completely areate; areation formula NR PR/PR, NR'/5', NRa/6a, NR''/7'', Xc, NR'''/7''', NR''''/3'''', Xs/as, y, z, ps; small apical penta PR;
- apical area series consisting of 5 irregular polyhedra, steno VI1' (V), large VI 2' (VVL), large VI 3' (DDL), large VI 4' (RDR) and large VI 5' (VVR);
- anterior intercalary group comprising 6 irregular polyhedra, lati VI 1a (L), minute trigonal 2a (DL), VI 3a (DDL), VII 4a (DR), minute trigonal 5a (RDR) and lati VI 6a (R);
- 7 precingulars, anteriorly geniculate V-nE 1'' (VVL), anteriorly geniculate V-nE 2'' (LVL), anteriorly bigeniculate VI-nE 3'' (DL), anteriorly geniculate V-nE 4'' (DR), anteriorly bigeniculate VI-nE 5'' (RDR), anteriorly geniculate V-nE 6'' (VR), anteriorly geniculate V-nE 7'' (VVR);
- cingulum a helicoid, laevorotatory, broad, level or weakly indented, usually indistinctly ornamented band marked by straight, exactly parallel, thickened ridges, nonareate or subdivided into 8 areae;
- 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''' (DL), posteriorly geniculate V-nE 5''' (D), posteriorly linear V-nE 6''' (RDR), posteriorly linear IV-nE 7''' (VVR);
- 3 large antapicals, VII 1'''' (VL), V 2'''' (DL), VI 3'''';
- sulcus partially subdivided, small as, hypocystal sulcus level or slightly indented, comprising a long, narrow z and a narrow, sigmoid ps;
- archaeopyle complex, comprising apicals and anterior intercalaries or pylome-like.
Affinities:
Below, 1987, p. 149
(annotated) The areation of D. priscum, except for the apex, agrees with that of D. ovale and D. polyedricum. The areation of the apex can be inferred from by comparing D. ovale; it confirms the description of Evitt, 1961. unlike on D. ovale, the minute trigonal areae 2a and 5a, located respectively between areae 3'', 1a and 3a, and 5'', 4a and 6a, are only very seldom found on D. priscum. their outlines are usually not traced by fines. But also, to the posterior, 3'' and 5'' are generally anteriorly geniculate, and not bigeniculate, as would be expected. Also Evitt, 1961, did not find corresponding areae.
Poulsen 1996, p. 81
Dapcodinium priscum Evitt 1961 emend. Dorhofer & Davies 1980 emend. Below 1987, Pl. 41, Fig. 15
Remarks. The occurrence of this species in large aggregates may be related to its preferred environment on the shallow shelf (see discussion under paleoenvironment and under distribution of zones) The aggregates may represent fecal pellets from zooplankton.
Recorded occurrences. Denmark: Rhaetogonyaulax rhaetica Zone - Dapcodinium priscum Zone, Subzone a.
The epithet was erroneously indicated as a noun in apposition in Fensome and Williams (2004).
Holotype: Evitt, 1961, pl.119, fig.1-2; text-fig.10-11
Locus typicus: Randers, Jutland, Denmark
Stratum typicum: Hettangian
Translation Below, 1987: Bureau of Translation, Secretary of State Canada, 1988, p. 378-381
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Dapcodinium priscum Evitt, 1961a, emend. Below, 1987a. According to Below (1987a, p 149)this species has a amphiesmal tabulation of PR, 5', 6a, 7", 8c, 7"’, 3"”, as, y, z, ps. It is proximate, acavate, spheroidal, epicyst and hypocyst of equal size; small; wall surface vermiculate to granulate, with very delicate low sutural crests and rows of granules, nontabulate, partly tabulate or completely tabulate. Tabulation formula: NR, PR/PR, ;5', 6a, 7", Xc, 7"’, 3"”, Xs. Archeopyle complex, comprising apicals and anterior intercalaries or pylome-like. The two cingular margins are always marked by low, but solid crests or rows of granules. PS is sigmoidal.
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Original description: Evitt, 1961, p. 996, 998
Diagnosis: Subspherical, with obtusely pointed apex; diameter 25-30 Ám. Theca less than 0.3 Ám thick, especially thin in the apical region. Sutures simple, slightly thickened. Tabulation: 4', 4a, 7'', 6g, 6''', 2p, 1''''. Plates 1-4a large and subequal, pentagonal; plates 1p and 2p large, 2p the larger; plates 1'' and 7'', 1''' and 6''' smaller than others of respective series; plate 1' asymmetrical, barely in contact with 7''. Girdle lefthanded, conspicuously wide (5-7 Ám), displaced slightly more than one girdle width. Ventral area large, chiefly on hypotheca; some boundaries of constituent plates usually visible. Rupture apparently by separation along sutures in apical region. Diameter: 25-30 Ám.
Emended description: Below 1987, p. 149
Arrangement of vesicles/plates on the dinoflagellate amphiesma PR, 5', 6a, 7'', 8c, 7'', 3'''', as, y, z, ps.
Cystic habit proximate, acavate, spheroidal, epicyst and hypocyst of equal size; size small; wall composed of thin pedium, surface vermiculate to granular with very delicate, low fineta crests and rows of granules, nonareate, partially areate, or completely areate; areation formula NR PR/PR, NR'/5', NRa/6a, NR''/7'', Xc, NR'''/7''', NR''''/3'''', Xs/as, y, z, ps; small apical penta PR;
- apical area series consisting of 5 irregular polyhedra, steno VI1' (V), large VI 2' (VVL), large VI 3' (DDL), large VI 4' (RDR) and large VI 5' (VVR);
- anterior intercalary group comprising 6 irregular polyhedra, lati VI 1a (L), minute trigonal 2a (DL), VI 3a (DDL), VII 4a (DR), minute trigonal 5a (RDR) and lati VI 6a (R);
- 7 precingulars, anteriorly geniculate V-nE 1'' (VVL), anteriorly geniculate V-nE 2'' (LVL), anteriorly bigeniculate VI-nE 3'' (DL), anteriorly geniculate V-nE 4'' (DR), anteriorly bigeniculate VI-nE 5'' (RDR), anteriorly geniculate V-nE 6'' (VR), anteriorly geniculate V-nE 7'' (VVR);
- cingulum a helicoid, laevorotatory, broad, level or weakly indented, usually indistinctly ornamented band marked by straight, exactly parallel, thickened ridges, nonareate or subdivided into 8 areae;
- 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''' (DL), posteriorly geniculate V-nE 5''' (D), posteriorly linear V-nE 6''' (RDR), posteriorly linear IV-nE 7''' (VVR);
- 3 large antapicals, VII 1'''' (VL), V 2'''' (DL), VI 3'''';
- sulcus partially subdivided, small as, hypocystal sulcus level or slightly indented, comprising a long, narrow z and a narrow, sigmoid ps;
- archaeopyle complex, comprising apicals and anterior intercalaries or pylome-like.
Affinities:
Below, 1987, p. 149
(annotated) The areation of D. priscum, except for the apex, agrees with that of D. ovale and D. polyedricum. The areation of the apex can be inferred from by comparing D. ovale; it confirms the description of Evitt, 1961. unlike on D. ovale, the minute trigonal areae 2a and 5a, located respectively between areae 3'', 1a and 3a, and 5'', 4a and 6a, are only very seldom found on D. priscum. their outlines are usually not traced by fines. But also, to the posterior, 3'' and 5'' are generally anteriorly geniculate, and not bigeniculate, as would be expected. Also Evitt, 1961, did not find corresponding areae.
Poulsen 1996, p. 81
Dapcodinium priscum Evitt 1961 emend. Dorhofer & Davies 1980 emend. Below 1987, Pl. 41, Fig. 15
Remarks. The occurrence of this species in large aggregates may be related to its preferred environment on the shallow shelf (see discussion under paleoenvironment and under distribution of zones) The aggregates may represent fecal pellets from zooplankton.
Recorded occurrences. Denmark: Rhaetogonyaulax rhaetica Zone - Dapcodinium priscum Zone, Subzone a.