Back
Fromea cooksoniae
From Fensome et al., 2019:
Fromea cooksoniae Fedorova-Shakhmundes, 1980, p.5–6, pl.1, figs.1–2. Holotype: Fedorova-Shakhmundes, 1980, pl.1, fig.1. Age: early Aptian
---------------------------------------------------------------------------------------------------
Original description: [Fedorova-Shakhmundes, 1980] (translated from Russian):
Fromea cooksoniae, Theodorova-Shakhumundes, sp. n.
Table 1, Fig. 1, 2
Fromea amphora: 1958, Cookson et Eisenack [150], p. 56 (pars), pl. Ѵ, fig. 11 pos. 10; 1964, Manum et Cookson [198], p. 27, pl. Ѵ, fig. 11; 1974, McIntyre [203], pl. VIII, fig. 18.
Holotype - No. 1230/1-14, VNIGRI, Leningrad; Caspian Lowland, Akmechet, borehole 3-K, depth 436-442 m; Lower Cretaceous, lower Aptian.
Material. 10 copies in good condition.
Description. The theca is rounded or ellipsoidally flattened, truncated at the apex in the region of the aperture. The aperture is apical, rounded (?), with a diameter approximately equal to 1/2-1/3 of the theca diameter, sometimes noticeably submerged, with uneven, slightly wavy edges. The girdle is equatorial, very narrow, barely visible; not observed in all specimens. The membrane (1.5-2.0 µm) is of uniform thickness along the contour, two-layered, with a smooth outer layer. The inner layer creates unevenly grained texture. Color light yellow. Dimensions, µm. Length 69-98.6 (71.0); Width 66.6-78.5 (61.6); Aperture diameter 23.3-35.7 (30.0).
Variability. The species varies in size, shape, shell thickness, the presence of the equatorial band (from barely noticeable to completely absent), the depth of the aperture, and its diameter.
Comparison. The species was isolated from the composition of Fromea amphora Cookson et Eisenack, for which the authors presented several significant images of the holotype and paratype. The new species differs from Fromea amphora in the broadly oval shape of the theca, a thinner shell, and a barely noticeable narrow equatorial band, which is sometimes absent. Based on these same characteristics, the specimens cited by S. Manum, I. Cookson [198], and D. McIntyre [203] and defined by these researchers as Fromea amphora should also be classified as the new species.
Location and stratigraphic setting. Caspian Lowland. Lower Cretaceous, Aptian. Western Australia. Lower Cretaceous, Albian. Arctic Canada. Upper Cretaceous, Cenomanian? Northwestern Canada. Upper Cretaceous, Campanian, possibly Santonian.
Fromea cooksoniae Fedorova-Shakhmundes, 1980, p.5–6, pl.1, figs.1–2. Holotype: Fedorova-Shakhmundes, 1980, pl.1, fig.1. Age: early Aptian
---------------------------------------------------------------------------------------------------
Original description: [Fedorova-Shakhmundes, 1980] (translated from Russian):
Fromea cooksoniae, Theodorova-Shakhumundes, sp. n.
Table 1, Fig. 1, 2
Fromea amphora: 1958, Cookson et Eisenack [150], p. 56 (pars), pl. Ѵ, fig. 11 pos. 10; 1964, Manum et Cookson [198], p. 27, pl. Ѵ, fig. 11; 1974, McIntyre [203], pl. VIII, fig. 18.
Holotype - No. 1230/1-14, VNIGRI, Leningrad; Caspian Lowland, Akmechet, borehole 3-K, depth 436-442 m; Lower Cretaceous, lower Aptian.
Material. 10 copies in good condition.
Description. The theca is rounded or ellipsoidally flattened, truncated at the apex in the region of the aperture. The aperture is apical, rounded (?), with a diameter approximately equal to 1/2-1/3 of the theca diameter, sometimes noticeably submerged, with uneven, slightly wavy edges. The girdle is equatorial, very narrow, barely visible; not observed in all specimens. The membrane (1.5-2.0 µm) is of uniform thickness along the contour, two-layered, with a smooth outer layer. The inner layer creates unevenly grained texture. Color light yellow. Dimensions, µm. Length 69-98.6 (71.0); Width 66.6-78.5 (61.6); Aperture diameter 23.3-35.7 (30.0).
Variability. The species varies in size, shape, shell thickness, the presence of the equatorial band (from barely noticeable to completely absent), the depth of the aperture, and its diameter.
Comparison. The species was isolated from the composition of Fromea amphora Cookson et Eisenack, for which the authors presented several significant images of the holotype and paratype. The new species differs from Fromea amphora in the broadly oval shape of the theca, a thinner shell, and a barely noticeable narrow equatorial band, which is sometimes absent. Based on these same characteristics, the specimens cited by S. Manum, I. Cookson [198], and D. McIntyre [203] and defined by these researchers as Fromea amphora should also be classified as the new species.
Location and stratigraphic setting. Caspian Lowland. Lower Cretaceous, Aptian. Western Australia. Lower Cretaceous, Albian. Arctic Canada. Upper Cretaceous, Cenomanian? Northwestern Canada. Upper Cretaceous, Campanian, possibly Santonian.