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Impagidinium maghribensis
Impagidinium maghribensis Slimani et al. 2008, p.331–332, 334, figs.4G–L.
Holotype: Slimani et al. 2008, figs.4G–K.
Age: early Danian.
Original description (Slimani et al., 2008):
Impagidinium maghribensis sp. nov. Fig. 4GeL
Derivation of name. Arabic ‘‘Al maghrib’’, with reference to the country of Morocco.
Holotype. Sample OH 17, slide 1, EF M27 (Fig. 4GeK).
Type locality and stratigraphic horizon. Ouled Haddou section, north of Taza, northern Morocco; marls 65 cm above the K/T boundary, lower Danian.
Diagnosis. Ellipsoidal and granulate to verrucate species of Impagidinium with a gonyaulacoid tabulation expressed by low, narrow sutural septa, and a characteristic absence of a sutural septum between apical plates 1’ and 4’ . Precingular, pentagonal archeopyle formed by loss of plate 3’’. Operculum detached.
Description. Proximate autocyst with an ellipsoidal ambitus. Cyst wall 1-1.5 µm thick, massive and coarsely granulate to verrucate. Granules and verrucae 0.5-2 µm diameter, densely and regularly distributed on wall surface. Hyaline, low and narrow sutural septa (up to 2 µm high) with solid bases reflect a tabulation pattern (4’ , 6’’, 6c, 6’’’, 1p, 1’’’’). Distal margins of processes curved to undulating. No septum observed between apical plates 1’ and 4’ (Fig. 4H, I, L). Precingular plate 6’’ subtriangular (Fig. 4L). Cingulum 4-5 µm wide. Tabulation of straight sulcal area not developed apart from posterior intercalary plate 1p, which is sometimes partially separated from sulcus by a discontinuous septum.
Dimensions (in µm). Holotype and range for 10 specimens measured: length 43, 42(45)50; width 32, 32(38)45.
Discussion. Impagidinium maghribensis sp. nov. is characterised by its coarsely granulate to verrucate wall surface, its narrow and low sutural septa, and the absence of a septum between plates 1’ and 4’ . Impagidinium maculatum (Cookson and Eisenack, 1961) Stover and Evitt, 1978 has a similar ornamentation but differs in its larger size, ovoid to nearly spherical shape, higher sutural septa, and the presence of a septum between 10 and 40 . Impagidinium sp. cf. I. patulum (Wall, 1967) Stover and Evitt, 1978 of Jan du Cheˆne (1988, pl. 20, figs 6e10; pl. 28, figs 1e4; text-fig. 4) has a granulate wall surface, but differs by having a septum that separates 1’ and 4’ . Impagidinium eugubinum Biffi and Manum, 1988 has an ornamentation of dome-shaped to nipple-like prominences rather than granules or verrucae, and also differs in having well-delimited apical plates 1’ and 4’ , and posterior sulcal plates. Impagidinium aspinatum (Cookson and Eisenack, 1974) Damassa, 1979a resembles I. maghribensis in its wall ornamentation, but differs in having an apical horn and a septum between 1’ and 4’ .
Stratigraphic occurrence. Samples OH 9e17, planktonic foraminiferal Guembelitria cretacea and Parvularugoglobigerina eugubina zones (lower Danian).
Holotype: Slimani et al. 2008, figs.4G–K.
Age: early Danian.
Original description (Slimani et al., 2008):
Impagidinium maghribensis sp. nov. Fig. 4GeL
Derivation of name. Arabic ‘‘Al maghrib’’, with reference to the country of Morocco.
Holotype. Sample OH 17, slide 1, EF M27 (Fig. 4GeK).
Type locality and stratigraphic horizon. Ouled Haddou section, north of Taza, northern Morocco; marls 65 cm above the K/T boundary, lower Danian.
Diagnosis. Ellipsoidal and granulate to verrucate species of Impagidinium with a gonyaulacoid tabulation expressed by low, narrow sutural septa, and a characteristic absence of a sutural septum between apical plates 1’ and 4’ . Precingular, pentagonal archeopyle formed by loss of plate 3’’. Operculum detached.
Description. Proximate autocyst with an ellipsoidal ambitus. Cyst wall 1-1.5 µm thick, massive and coarsely granulate to verrucate. Granules and verrucae 0.5-2 µm diameter, densely and regularly distributed on wall surface. Hyaline, low and narrow sutural septa (up to 2 µm high) with solid bases reflect a tabulation pattern (4’ , 6’’, 6c, 6’’’, 1p, 1’’’’). Distal margins of processes curved to undulating. No septum observed between apical plates 1’ and 4’ (Fig. 4H, I, L). Precingular plate 6’’ subtriangular (Fig. 4L). Cingulum 4-5 µm wide. Tabulation of straight sulcal area not developed apart from posterior intercalary plate 1p, which is sometimes partially separated from sulcus by a discontinuous septum.
Dimensions (in µm). Holotype and range for 10 specimens measured: length 43, 42(45)50; width 32, 32(38)45.
Discussion. Impagidinium maghribensis sp. nov. is characterised by its coarsely granulate to verrucate wall surface, its narrow and low sutural septa, and the absence of a septum between plates 1’ and 4’ . Impagidinium maculatum (Cookson and Eisenack, 1961) Stover and Evitt, 1978 has a similar ornamentation but differs in its larger size, ovoid to nearly spherical shape, higher sutural septa, and the presence of a septum between 10 and 40 . Impagidinium sp. cf. I. patulum (Wall, 1967) Stover and Evitt, 1978 of Jan du Cheˆne (1988, pl. 20, figs 6e10; pl. 28, figs 1e4; text-fig. 4) has a granulate wall surface, but differs by having a septum that separates 1’ and 4’ . Impagidinium eugubinum Biffi and Manum, 1988 has an ornamentation of dome-shaped to nipple-like prominences rather than granules or verrucae, and also differs in having well-delimited apical plates 1’ and 4’ , and posterior sulcal plates. Impagidinium aspinatum (Cookson and Eisenack, 1974) Damassa, 1979a resembles I. maghribensis in its wall ornamentation, but differs in having an apical horn and a septum between 1’ and 4’ .
Stratigraphic occurrence. Samples OH 9e17, planktonic foraminiferal Guembelitria cretacea and Parvularugoglobigerina eugubina zones (lower Danian).