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Fromea tornatilis
From Fensome et al., 2019:
Fromea tornatilis (Drugg, 1978, p.71–72, pl.7, figs.4–6) Lentin and Williams, 1981, p.107. Holotype: Drugg, 1978, pl.7, fig.5. Originally Palaeostomocystis (Appendix A), subsequently (and now) Fromea. Age: Callovian–Oxfordian.
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Original description (Drugg, 1978):
Palaeostomocystis tornatilis DRUGG, n. sp.
Pl. 7, figs. 4-6
Description: Cyst flask-shaped, more or less elliptical in outline, varying from oval to somewhat elongate. A circular aperture, about 13 μm in diameter, is located at the apex. The wall on different specimens varies in thickness from about 0.5 to 2 μm. The wall thins at the aperture and often forms a narrow rim. Sometimes there is a slight internal thickening just below the abrupt thinning which produces a more dense appearance at this point. The wall surface is slightly roughened or shagreen to finely granulate. Some specimens exhibit a faint narrow band (depression or thinning) which encircles the body midway and thereby is suggestive of a paracingulum. The cyst ranges in length from 54 to 80 μm and the width ranges from 42 to 54 μm. Measurements based on 25 specimens.
Types and occurrence: Holotype Pl. 7, fig. 5, Woodham Brick Pit, Budkinghamshire, England, Oxford Clay, Callovian, P. athleta Zone, 7' below the Lamberti Limestone. Isotype P. 7, fig. 4, Warboys Brick Pit, Huntingdonshire, England, Oxfordian, Q. mariae Zone, Oxford Clay, 5' below base of Ampthill Clay. Figured specimen Pl. 7, fig. 6, Calvert Brickworks, Bucinghamshire, England, Callovian, E. coronatum Zone, 34 1/2' above basal shell bed.
Remarks: This species resembles Fromea amphora COOKSON & EISENACK, 1958, but differs in possessing a narrower aperture without a thickened rim. In addition many of the specimens are more elongate and the majority do not exhibit a "paracingulum". Palaeostomocystis cylindrica COOKSON & EISENACK, 1960 differs in outline and is reticulate. P. laevigata DRUGG, 1967, is more elongate and most definitely has a much thinner and smoother wall. The species Alisunm magnum and A. parvum GÓRKA, 1965, are generally similar to P. tornatilis but bear extended apical collars. Furthermore A. parvum sometimes occurs in chains. The affinities of Alisum are unknown. P. tornatilis is quite abundant in many samples. The specific name is from the Latin tornatilis for beautifully rounded.
Fromea tornatilis (Drugg, 1978, p.71–72, pl.7, figs.4–6) Lentin and Williams, 1981, p.107. Holotype: Drugg, 1978, pl.7, fig.5. Originally Palaeostomocystis (Appendix A), subsequently (and now) Fromea. Age: Callovian–Oxfordian.
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Original description (Drugg, 1978):
Palaeostomocystis tornatilis DRUGG, n. sp.
Pl. 7, figs. 4-6
Description: Cyst flask-shaped, more or less elliptical in outline, varying from oval to somewhat elongate. A circular aperture, about 13 μm in diameter, is located at the apex. The wall on different specimens varies in thickness from about 0.5 to 2 μm. The wall thins at the aperture and often forms a narrow rim. Sometimes there is a slight internal thickening just below the abrupt thinning which produces a more dense appearance at this point. The wall surface is slightly roughened or shagreen to finely granulate. Some specimens exhibit a faint narrow band (depression or thinning) which encircles the body midway and thereby is suggestive of a paracingulum. The cyst ranges in length from 54 to 80 μm and the width ranges from 42 to 54 μm. Measurements based on 25 specimens.
Types and occurrence: Holotype Pl. 7, fig. 5, Woodham Brick Pit, Budkinghamshire, England, Oxford Clay, Callovian, P. athleta Zone, 7' below the Lamberti Limestone. Isotype P. 7, fig. 4, Warboys Brick Pit, Huntingdonshire, England, Oxfordian, Q. mariae Zone, Oxford Clay, 5' below base of Ampthill Clay. Figured specimen Pl. 7, fig. 6, Calvert Brickworks, Bucinghamshire, England, Callovian, E. coronatum Zone, 34 1/2' above basal shell bed.
Remarks: This species resembles Fromea amphora COOKSON & EISENACK, 1958, but differs in possessing a narrower aperture without a thickened rim. In addition many of the specimens are more elongate and the majority do not exhibit a "paracingulum". Palaeostomocystis cylindrica COOKSON & EISENACK, 1960 differs in outline and is reticulate. P. laevigata DRUGG, 1967, is more elongate and most definitely has a much thinner and smoother wall. The species Alisunm magnum and A. parvum GÓRKA, 1965, are generally similar to P. tornatilis but bear extended apical collars. Furthermore A. parvum sometimes occurs in chains. The affinities of Alisum are unknown. P. tornatilis is quite abundant in many samples. The specific name is from the Latin tornatilis for beautifully rounded.