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Batiacasphaera rifensis
Batiacasphaera rifensis, Slimani et al., 2008, p.338,340, figs.9A–F.
Holotype: Slimani et al., 2008, figs.9D–E.
Type locality and stratigraphic horizon: Ouled Haddou section, north of Taza, northern Morocco; clayey marls, 35 cm above the K/T boundary; lower Danian.
Stratigraphic occurrence: Samples OH 7e19, planktonic foraminiferal Guembelitria cretacea and Parvularugoglobigerina eugubina zones; lower Danian, Ouled Haddou section;?- Campanian Maastrichtian of northwest Egypt (Schrank and Ibrahim, 1995); Maastrichtian of southern Patagonia, Argentina (Marenssi et al., 2004).
Age: early Danian.
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Original description: [Slimani et al., 2008]:
Diagnosis:
Ovoid to subspherical Batiacasphaera with relatively thick and reticulate autophragm. Reticulum irregular, with low muri delimiting small, variable lumina.
Large apical archeopyle, type tA, with zigzag margin, operculum mostly free, occasionally in place.
Tabulation not indicated apart from archeopyle margin and operculum outline.
Description:
Acavate, proximate, ovoid to subspherical gonyaulacoid dinoflagellate cyst.
Cyst wall consists of a massive, relatively thick (up to 2 µm) and irregularly reticulate autophragm. Lumina of reticulum small (up to 3 µm), vary in size and shape on a single specimen. Muri low (up to 0.5 µm) and variable in thickness.
Cingulum and sulcus not indicated.
Archeopyle is apical type (tA), large with a sulcal notch and zigzag margin. On some specimens accessory sutures are present; operculum is angular in shape, simple and generally free but sometimes attached (Fig. 9A, B).
Tabulation not indicated apart from archeopyle margin and operculum outline, suggesting six precingular and four apical plates.
Dimensions (in µm):
Holotype, paratype and range for 26 specimens measured: length (with operculum, holotype) 45, 42(48)52; length (without operculum, paratype) 45, 35(40)47; width 42, 40, 35(43)47.
Affinities/Discussion:
Batiacasphaera rifensis sp. nov. is similar to B. cf. reticulata figured by Schrank and Ibrahim (1995, pl. 9, fig. 7) in having a large archeopyle and pronounced reticulum. It differs from B. reticulata (Davey, 1969) Davey, 1979 in being much larger, and in having a more pronounced and irregular reticulum, and a larger archeopyle with a strongly angular margin. As described by Davey (1969), B. reticulata has a very delicate surface reticulation, which can only be observed under high magnification. Batiacasphaera cassiculus Wilson, 1988 differs from B. rifensis in being larger and in having a thicker autophragm and a much more variable reticulum with more pronounced and thicker muri; B. imperfecta Stover and Helby, 1987 has an imperfect reticulum; B. kekerengensis Schiøler and Wilson, 1998 is larger and has a regular reticulum.
Holotype: Slimani et al., 2008, figs.9D–E.
Type locality and stratigraphic horizon: Ouled Haddou section, north of Taza, northern Morocco; clayey marls, 35 cm above the K/T boundary; lower Danian.
Stratigraphic occurrence: Samples OH 7e19, planktonic foraminiferal Guembelitria cretacea and Parvularugoglobigerina eugubina zones; lower Danian, Ouled Haddou section;?- Campanian Maastrichtian of northwest Egypt (Schrank and Ibrahim, 1995); Maastrichtian of southern Patagonia, Argentina (Marenssi et al., 2004).
Age: early Danian.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Slimani et al., 2008]:
Diagnosis:
Ovoid to subspherical Batiacasphaera with relatively thick and reticulate autophragm. Reticulum irregular, with low muri delimiting small, variable lumina.
Large apical archeopyle, type tA, with zigzag margin, operculum mostly free, occasionally in place.
Tabulation not indicated apart from archeopyle margin and operculum outline.
Description:
Acavate, proximate, ovoid to subspherical gonyaulacoid dinoflagellate cyst.
Cyst wall consists of a massive, relatively thick (up to 2 µm) and irregularly reticulate autophragm. Lumina of reticulum small (up to 3 µm), vary in size and shape on a single specimen. Muri low (up to 0.5 µm) and variable in thickness.
Cingulum and sulcus not indicated.
Archeopyle is apical type (tA), large with a sulcal notch and zigzag margin. On some specimens accessory sutures are present; operculum is angular in shape, simple and generally free but sometimes attached (Fig. 9A, B).
Tabulation not indicated apart from archeopyle margin and operculum outline, suggesting six precingular and four apical plates.
Dimensions (in µm):
Holotype, paratype and range for 26 specimens measured: length (with operculum, holotype) 45, 42(48)52; length (without operculum, paratype) 45, 35(40)47; width 42, 40, 35(43)47.
Affinities/Discussion:
Batiacasphaera rifensis sp. nov. is similar to B. cf. reticulata figured by Schrank and Ibrahim (1995, pl. 9, fig. 7) in having a large archeopyle and pronounced reticulum. It differs from B. reticulata (Davey, 1969) Davey, 1979 in being much larger, and in having a more pronounced and irregular reticulum, and a larger archeopyle with a strongly angular margin. As described by Davey (1969), B. reticulata has a very delicate surface reticulation, which can only be observed under high magnification. Batiacasphaera cassiculus Wilson, 1988 differs from B. rifensis in being larger and in having a thicker autophragm and a much more variable reticulum with more pronounced and thicker muri; B. imperfecta Stover and Helby, 1987 has an imperfect reticulum; B. kekerengensis Schiøler and Wilson, 1998 is larger and has a regular reticulum.