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Pterodinium cretaceum
Pterodinium cretaceum Slimani et al., 2008, p.334, figs.4A–F.
Holotype: Slimani et al., 2008, figs.4A–D.
Age: late Maastrichtian.
Original description (Slimani et al., 2008):
Pterodinium cretaceum sp. nov. Fig. 4AeF
1993 Pterodinium sp. B, Schiøler and Wilson, figs. 3e10, pl. 4, figs. 13, 14.
1997a Pterodinium sp. B, Schiøler and Wilson, 1993; Roncaglia and Corradini, figs. 6e8.
1997b Pterodinium sp. B, Schiøler and Wilson, 1993; Roncaglia and Corradini, fig. 4, pl. 3, figs. 6, 8.
2003 Pterodinium sp. B sensu Schiøler and Wilson, 1993; Torricelli and Amore, pl. 1, figs. 19, 20.
Derivation of name. After ‘‘Cretaceous’’, with reference to the CampanianeMaastrichtian occurrences of the species.
Holotype. Sample OH 2, slide 2, EF R45/3 (Fig. 4AeD).
Type locality and stratigraphic horizon. Ouled Haddou section, north of Taza, northern Morocco; marls 50 cm below the K/T boundary; upper Maastrichtian.
Diagnosis. Spherical to ovoid, smooth and thin-walled Pterodinium characterised by high sutural septa with slightly convex distal margin. Gonyaulacoid tabulation with discontinuous septa on ventral area. Archeopyle formed by release of precingular plate 3’’. Operculum free or in place.
Description. Acavate to murochorate, spherical to ovoidal autocyst. Cyst wall 0.5 - 1 µm thick, smooth. Hyaline, smooth and high septa (about one-third of central body diameter) arise from cyst body. Distal margins of septa are slightly convex and enlarged. Observed tabulation is gonyaulacoid (4’ , 6’’, 6c, 6’’’, 1p, 1’’’’), but difficult to observe when septa are folded. Cingulum 5 -12 µm wide, slightly laevorotatory. Discontinuous septa in sulcal area do not reflect tabulation. Sutural septa 1’’/1c, 6’’/6c, 1c/1’’’, 6c/6’’’’ and those between the sulcus and 1’’, 6’’, 1c, 6c are usually absent (Fig. 4D, F).
Dimensions (in m=µm). Holotype and range for 10 specimens measured: length of central body 28, 27(30)32; width of central body 28, 25(28)30; height of septa 6-12, 5-12.
Discussion. The new species is conspecific with Pterodinium sp. B of Schiøler and Wilson (1993, pl. 4, figs 13e14). It differs from other species of the genus in having discontinuous septa in the ventral area.
Stratigraphic occurrence. Samples OH 1e5, planktonic foraminiferal Abpthomphalus mayaroensis Zone (upper Maastrichtian), Ouled Haddou section; Maastrichtian of the Danish North Sea (Schiøler and Wilson, 1993); upper Campaniane lower Maastrichtian of Turnhout (Belgium) (Slimani, 1995, 2000, 2001); Maastrichtian of northern Apennines (Italy) (Roncaglia and Corradini, 1997a,b); Upper Campaniane Lower Maastrichtian of Calabria (Italy) (Torricelli and Amore, 2003).
Holotype: Slimani et al., 2008, figs.4A–D.
Age: late Maastrichtian.
Original description (Slimani et al., 2008):
Pterodinium cretaceum sp. nov. Fig. 4AeF
1993 Pterodinium sp. B, Schiøler and Wilson, figs. 3e10, pl. 4, figs. 13, 14.
1997a Pterodinium sp. B, Schiøler and Wilson, 1993; Roncaglia and Corradini, figs. 6e8.
1997b Pterodinium sp. B, Schiøler and Wilson, 1993; Roncaglia and Corradini, fig. 4, pl. 3, figs. 6, 8.
2003 Pterodinium sp. B sensu Schiøler and Wilson, 1993; Torricelli and Amore, pl. 1, figs. 19, 20.
Derivation of name. After ‘‘Cretaceous’’, with reference to the CampanianeMaastrichtian occurrences of the species.
Holotype. Sample OH 2, slide 2, EF R45/3 (Fig. 4AeD).
Type locality and stratigraphic horizon. Ouled Haddou section, north of Taza, northern Morocco; marls 50 cm below the K/T boundary; upper Maastrichtian.
Diagnosis. Spherical to ovoid, smooth and thin-walled Pterodinium characterised by high sutural septa with slightly convex distal margin. Gonyaulacoid tabulation with discontinuous septa on ventral area. Archeopyle formed by release of precingular plate 3’’. Operculum free or in place.
Description. Acavate to murochorate, spherical to ovoidal autocyst. Cyst wall 0.5 - 1 µm thick, smooth. Hyaline, smooth and high septa (about one-third of central body diameter) arise from cyst body. Distal margins of septa are slightly convex and enlarged. Observed tabulation is gonyaulacoid (4’ , 6’’, 6c, 6’’’, 1p, 1’’’’), but difficult to observe when septa are folded. Cingulum 5 -12 µm wide, slightly laevorotatory. Discontinuous septa in sulcal area do not reflect tabulation. Sutural septa 1’’/1c, 6’’/6c, 1c/1’’’, 6c/6’’’’ and those between the sulcus and 1’’, 6’’, 1c, 6c are usually absent (Fig. 4D, F).
Dimensions (in m=µm). Holotype and range for 10 specimens measured: length of central body 28, 27(30)32; width of central body 28, 25(28)30; height of septa 6-12, 5-12.
Discussion. The new species is conspecific with Pterodinium sp. B of Schiøler and Wilson (1993, pl. 4, figs 13e14). It differs from other species of the genus in having discontinuous septa in the ventral area.
Stratigraphic occurrence. Samples OH 1e5, planktonic foraminiferal Abpthomphalus mayaroensis Zone (upper Maastrichtian), Ouled Haddou section; Maastrichtian of the Danish North Sea (Schiøler and Wilson, 1993); upper Campaniane lower Maastrichtian of Turnhout (Belgium) (Slimani, 1995, 2000, 2001); Maastrichtian of northern Apennines (Italy) (Roncaglia and Corradini, 1997a,b); Upper Campaniane Lower Maastrichtian of Calabria (Italy) (Torricelli and Amore, 2003).