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Cribroperidinium hansenii
Cribroperidinium hansenii Poulsen 1996
Cribroperidinium sp. A of Davey, 1982, p. 27-28, pl. 10, figs. 5,6.
Poulsen 1996, p. 75-76
Cribroperidinium hansenii sp. nov
Pl. 9, Figs. 1-4, Pl. 10, Figs. 1-3
Diagnosis. A large proximate cyst generally with a long, slender, hollow apical horn which may terminate in an apicular structure. The body is ovoidal to subpolygonal. Autophragm only. Parasutures marked by low, denticulate ridges. Surfaces covered with low spinules. Accessory ridges present. Paratabulation gonyaulacoid, sexiform. Archeopyle, type P3~, operculum free. Paracingulum descending. Parasulcus long and broad.
Description. A large, ovoidal to subpolygonal species of Cribroperidinium with a thick, vesicular wall (i.e. the wall possesses scattered small bubbles, about 0.25-0.5 Ám in size) and, generally, a long apical horn. The vesicles are best seen in the apical horn (Pl. 9, Fig. 1), which is hollow for about one third to half of its length. The paratabulation is defined by low ridges which bear small to large spines, in average 3 Ám long. The spines are particularly well-developed at the base of the apical horn, along the paracingular margins, and around the antapical paraplate. The paraplates possess accessory ridges and numerous granules.
Dimensions. 25 specimens measured.
Holotype: length 125 Ám, width 99 ,um, length of horn 25 Ám.
Paratype MPK 8885: length 143 Ám, width 83 Ám, length of horn 46 Ám.
Paratype MPK 8886: length 111 Ám, width 76 Ám, length of horn 26 Ám. Paratype MPK 8887: length 146 Ám, width 65 Ám, length of horn 57 Ám.
Overall cyst length (minimum-mean-maximum): 102 Ám - 130 Ám - 149 Ám. Overall cyst width (minimum-mean-maximum): 65 Ám - 81 Ám - 102 Ám. The horn of C. hansenii is generally between 30-40 Ám long, but can vary from 20 Ám to 60 Ám within the same sample. A few specimens develop only a small, less distinct horn about 20 Ám long. In such specimens the distal massive end of the horn may be very short, and is probably in part missing due to breakage. A few specimens possess a very long horn, about 50-60 Ám long. The body varies in length from about 80 Ám to 100 Ám. The overall length is from 100 Ám to almost 150 Ám. The width is generally about 70-90 Ám. The English specimens in general have a slightly smaller body but longer horn than the Danish specimens.
Remarks. Bailey (1993) included Cribroperidinium sp. A of Davey, (1982, p. 27, pl. 10, figs. 56) in C. gigas, this is not followed here.
Comparison. Cribroperidinium hansenii differs from C.? Iongicorne (Downie 1957) Lentin and Williams 1985 in having a thicker and more ornamented wall, and a more distinct paratabulation. Cribroperidinium? gigas (Raynaud, 1978) Helenes 1984 is larger and has low, thick parasutural ridges without spines. Cribroperidinium sarjeantii (Vozzhennikova 1967) Helenes 1984 has fibrous parasutural ridges and a smaller massive apical horn. In only one of the figured specimens of C. sarjeantii (Lentin and Vozzhennikova, 1990, pl. 16, fig. 3) the horn has a short blunt hollow part at the base, whereas the other figured specimens of this species have a massive horn.
Occurrences. In Denmark this species occurs from the Dichadogonyaulax culmula Zone, Subzone a to the Scriniodinium pharo Zone (Middle Volgian - Valanginian). This study: Aars-1 ST3 at 2374 m (D. culmula Zone, Subzone a), Haldager-1 at 3251 ft. (D. spinosa Zone), Hyllebjerg1 at 5890 ft. (top occurrence in ditch cuttings, D. spinosum Zone), Skagen-2 at 1078 ft. (D. culmula Zone, Subzone a), and Vinding-1 at 4612-20 ft. (R. thula Subzone, G. villosa Zone). It is common in the upper part of the Frederikshavn Formation, cycle b equivalent to the most coarse-grained part of cycle b. It is very common in the Okusensis to Primitivus Zones of Eastern England (Middle Late Volgian) (Davey, 1982).
Holotype. Pl. 9, Figs. 1-2; DGU catalogue no.: 1991-NEP-12; from Haldager-1 borehole at 2989-3009 ft., Frederikshavn Formation, Middle Volgian, D. spinosum Zone.
Paratypes. Pl. 9, Figs. 3-4, Pl. 10, Figs. 1-3; BGS catalogue no.: MPK 8885, 8886, and 8887), all three from Nettleton (Nat. grit. ref. TF 107 994), Lincolnshire, Bed 1 of Casey (1973, p. 205), Giganteus Zone, sample SAL 5254, slide 3.
Cribroperidinium sp. A of Davey, 1982, p. 27-28, pl. 10, figs. 5,6.
Poulsen 1996, p. 75-76
Cribroperidinium hansenii sp. nov
Pl. 9, Figs. 1-4, Pl. 10, Figs. 1-3
Diagnosis. A large proximate cyst generally with a long, slender, hollow apical horn which may terminate in an apicular structure. The body is ovoidal to subpolygonal. Autophragm only. Parasutures marked by low, denticulate ridges. Surfaces covered with low spinules. Accessory ridges present. Paratabulation gonyaulacoid, sexiform. Archeopyle, type P3~, operculum free. Paracingulum descending. Parasulcus long and broad.
Description. A large, ovoidal to subpolygonal species of Cribroperidinium with a thick, vesicular wall (i.e. the wall possesses scattered small bubbles, about 0.25-0.5 Ám in size) and, generally, a long apical horn. The vesicles are best seen in the apical horn (Pl. 9, Fig. 1), which is hollow for about one third to half of its length. The paratabulation is defined by low ridges which bear small to large spines, in average 3 Ám long. The spines are particularly well-developed at the base of the apical horn, along the paracingular margins, and around the antapical paraplate. The paraplates possess accessory ridges and numerous granules.
Dimensions. 25 specimens measured.
Holotype: length 125 Ám, width 99 ,um, length of horn 25 Ám.
Paratype MPK 8885: length 143 Ám, width 83 Ám, length of horn 46 Ám.
Paratype MPK 8886: length 111 Ám, width 76 Ám, length of horn 26 Ám. Paratype MPK 8887: length 146 Ám, width 65 Ám, length of horn 57 Ám.
Overall cyst length (minimum-mean-maximum): 102 Ám - 130 Ám - 149 Ám. Overall cyst width (minimum-mean-maximum): 65 Ám - 81 Ám - 102 Ám. The horn of C. hansenii is generally between 30-40 Ám long, but can vary from 20 Ám to 60 Ám within the same sample. A few specimens develop only a small, less distinct horn about 20 Ám long. In such specimens the distal massive end of the horn may be very short, and is probably in part missing due to breakage. A few specimens possess a very long horn, about 50-60 Ám long. The body varies in length from about 80 Ám to 100 Ám. The overall length is from 100 Ám to almost 150 Ám. The width is generally about 70-90 Ám. The English specimens in general have a slightly smaller body but longer horn than the Danish specimens.
Remarks. Bailey (1993) included Cribroperidinium sp. A of Davey, (1982, p. 27, pl. 10, figs. 56) in C. gigas, this is not followed here.
Comparison. Cribroperidinium hansenii differs from C.? Iongicorne (Downie 1957) Lentin and Williams 1985 in having a thicker and more ornamented wall, and a more distinct paratabulation. Cribroperidinium? gigas (Raynaud, 1978) Helenes 1984 is larger and has low, thick parasutural ridges without spines. Cribroperidinium sarjeantii (Vozzhennikova 1967) Helenes 1984 has fibrous parasutural ridges and a smaller massive apical horn. In only one of the figured specimens of C. sarjeantii (Lentin and Vozzhennikova, 1990, pl. 16, fig. 3) the horn has a short blunt hollow part at the base, whereas the other figured specimens of this species have a massive horn.
Occurrences. In Denmark this species occurs from the Dichadogonyaulax culmula Zone, Subzone a to the Scriniodinium pharo Zone (Middle Volgian - Valanginian). This study: Aars-1 ST3 at 2374 m (D. culmula Zone, Subzone a), Haldager-1 at 3251 ft. (D. spinosa Zone), Hyllebjerg1 at 5890 ft. (top occurrence in ditch cuttings, D. spinosum Zone), Skagen-2 at 1078 ft. (D. culmula Zone, Subzone a), and Vinding-1 at 4612-20 ft. (R. thula Subzone, G. villosa Zone). It is common in the upper part of the Frederikshavn Formation, cycle b equivalent to the most coarse-grained part of cycle b. It is very common in the Okusensis to Primitivus Zones of Eastern England (Middle Late Volgian) (Davey, 1982).
Holotype. Pl. 9, Figs. 1-2; DGU catalogue no.: 1991-NEP-12; from Haldager-1 borehole at 2989-3009 ft., Frederikshavn Formation, Middle Volgian, D. spinosum Zone.
Paratypes. Pl. 9, Figs. 3-4, Pl. 10, Figs. 1-3; BGS catalogue no.: MPK 8885, 8886, and 8887), all three from Nettleton (Nat. grit. ref. TF 107 994), Lincolnshire, Bed 1 of Casey (1973, p. 205), Giganteus Zone, sample SAL 5254, slide 3.