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Subtilisphaera cinctuta
Subtilisphaera cinctuta Roncaglia and Corradini, 1997, p.189,192, pl.5, figs.7–8.
Holotype: Roncaglia and Corradini, 1997, pl.5, fig.7.
Age: middle Maastrichtian.
Original description (Roncaglia and Corradini, 1997)
Holotype: Cyst No. SG 31a/D39 (Plate V, 7).
Paratype: Cyst No. SG 31a/Z41-4 (Plate V, 8).
Repository: Department of Earth Science, University of Modena, Italy.
Type locality: Solignano, Taro Valley, Parma, Italy.
Stratigraphic horizon: Solignano Formation, at 215 m above the base of the formation.
Etymology: Latin, cinctutus, wearing a short skirt, with reference to the shape of the hypopericoel.
Diagnosis: Bicavate, elongate peridinoid cyst with one apical and two asymmetrical antapical projections. The endocyst is subspherical and smooth; the periphragm is shagreenate. The paratabulation pattern is indicated by the paracingulum only. The archeopyle is not discernible.
Description: Cyst bicavate, the pericyst has a rounded apical horn and two sharp, hollow, antapical projections of unequal length (left horn length 8 10 µm; right horn length 1 2 µm). The endocyst is subspherical in ambital view, thick-walled and smooth. The periphragm is thin and shagreenate.
The endophragm and periphragm are appressed, except in the apical and antapical areas where two pericoels are developed. The epipericyst has a subtriangular shape, with slightly convex lateral sides, whereas the hypopericyst has concave lateral sides (Plate 5, 7). The paracingulum is expressed by low continuous equatorial ridges on the periphragm. The parasulcus is not discernible. An archeopyle has not been observed. The paratabulation is indicated by the paracingulum only. Dimensions (4 specimens measured, range in µm): overall length 97-(100)-110; overall width 58 (61) 69; length of endocyst 57 (60) 63; width of endocyst 56-(58)-63.
Comparison: Subtilisphaera bulcattensis (Cookson et Eisenack, 1969) Lentin et Williams, 1993,
SubtiIisphaera circularis He Chengquan in Zheng Yahui and He Chengquan, 1984, Subtilisphaera ehmgata He Chengquan in Zheng Yahui and He Chengquan, 1984, Subtilisphaerafoliaceu (Cookson et Eisenack, 1960) Stover et Evitt, 1978 and Subtilisphaera scabrella He Chengquan in Zheng Yahui and He Chengquan, 1984 differ from S. cinctuta by being remarkably smaller. Subtilisphaera perlucida (Alberti, 1959) Jain et Millepied, 1973 differs from the new species by being circumcavate and lacking an apical horn. Subtilisphaera? trendalli
(Cookson et Eisenack, 1970) Lentin et Williams, 1993 closely resembles the new species in general appearance and size, but differs in having one antapical projection only and discontinuous paracingular ridges on the ventral surface.
Holotype: Roncaglia and Corradini, 1997, pl.5, fig.7.
Age: middle Maastrichtian.
Original description (Roncaglia and Corradini, 1997)
Holotype: Cyst No. SG 31a/D39 (Plate V, 7).
Paratype: Cyst No. SG 31a/Z41-4 (Plate V, 8).
Repository: Department of Earth Science, University of Modena, Italy.
Type locality: Solignano, Taro Valley, Parma, Italy.
Stratigraphic horizon: Solignano Formation, at 215 m above the base of the formation.
Etymology: Latin, cinctutus, wearing a short skirt, with reference to the shape of the hypopericoel.
Diagnosis: Bicavate, elongate peridinoid cyst with one apical and two asymmetrical antapical projections. The endocyst is subspherical and smooth; the periphragm is shagreenate. The paratabulation pattern is indicated by the paracingulum only. The archeopyle is not discernible.
Description: Cyst bicavate, the pericyst has a rounded apical horn and two sharp, hollow, antapical projections of unequal length (left horn length 8 10 µm; right horn length 1 2 µm). The endocyst is subspherical in ambital view, thick-walled and smooth. The periphragm is thin and shagreenate.
The endophragm and periphragm are appressed, except in the apical and antapical areas where two pericoels are developed. The epipericyst has a subtriangular shape, with slightly convex lateral sides, whereas the hypopericyst has concave lateral sides (Plate 5, 7). The paracingulum is expressed by low continuous equatorial ridges on the periphragm. The parasulcus is not discernible. An archeopyle has not been observed. The paratabulation is indicated by the paracingulum only. Dimensions (4 specimens measured, range in µm): overall length 97-(100)-110; overall width 58 (61) 69; length of endocyst 57 (60) 63; width of endocyst 56-(58)-63.
Comparison: Subtilisphaera bulcattensis (Cookson et Eisenack, 1969) Lentin et Williams, 1993,
SubtiIisphaera circularis He Chengquan in Zheng Yahui and He Chengquan, 1984, Subtilisphaera ehmgata He Chengquan in Zheng Yahui and He Chengquan, 1984, Subtilisphaerafoliaceu (Cookson et Eisenack, 1960) Stover et Evitt, 1978 and Subtilisphaera scabrella He Chengquan in Zheng Yahui and He Chengquan, 1984 differ from S. cinctuta by being remarkably smaller. Subtilisphaera perlucida (Alberti, 1959) Jain et Millepied, 1973 differs from the new species by being circumcavate and lacking an apical horn. Subtilisphaera? trendalli
(Cookson et Eisenack, 1970) Lentin et Williams, 1993 closely resembles the new species in general appearance and size, but differs in having one antapical projection only and discontinuous paracingular ridges on the ventral surface.