Ammodiscus tenuissimus ( Gümbel, 1862 )

Benedetti, A, 2017, Eocene / Oligocene deep-water agglutinated foraminifers (DWAF) assemblages from the Madonie Mountains (Sicily, Southern Italy), Palaeontologia Electronica 20 (1), pp. 1-66 : 25

Ammodiscus tenuissimus ( Gümbel, 1862)

Figure 13.9-11

1862 S pirillina tenuissima; Gümbel, p. 214, pl. 13, fig. 2.

1898 Ammodiscus tenuissimus ; Grzybowski, p. 282, pl. 10, fig. 35.

1966 Ammodiscus tenuissimus Guembel ; Geroch, p. 437, fig. 8 (1, 4).

1993 Ammodiscus tenuissimus Grzybowski ; Kaminski and Geroch, p. 253, figs. 1-3b.

1995 Ammodiscus tenuissimus Gümbel ; Holbourn and Kaminski, p. 442, pl. III, fig. 1.

1996 Ammodiscus tenuissimus Grzybowski ; Kaminski, Kuhnt, and Radley, p. 10, pl. 1, fig. 4.

Material. 25 specimens from eight samples.

Description. Test free, small size (less than 0.5

mm), very thin and flattened, circular or weakly elliptical, composed of a single chambers planispirally arranged in several closest whorls. Wall thin,

finely agglutinated. Aperture terminal.

Distribution. Cosmopolitan species common from the Late Cretaceous to the Eocene ( Kaminski and

Gradstein, 2005). Recently signaled from the Miocene of the Greenland Sea ( Kaminski et al., 2006).

Figures

FIGURE 13. Scanning electron micrographs of Psammosphaeridae (1-4) and Ammodiscidae (5-27) from the Caltavuturo Formation cropping out at Portella Colla. 1, Psammosphaera cf. laevigata White, 1928, PCs0. 2, Psammosphaera sp. 1, PC13. 3, Psammosphaera sp. 2, PC060615. 4, Psammosphaera sp. 3, PC060625. 5, Ammodiscus cretaceus (Reuss, 1845), PC22. 6, Hyperammina sp., PC060625. 7-8, Ammodiscus incertus (d’Orbigny, 1839), PC060603 (7) and PC13 (8). 9-11, Ammodiscus tenuisimus (Gümbel, 1862), PC22 (9), PC060615 (10) and PC060615 (11). 12-13, Ammodiscus latus Grzybowski, 1898, PC11 (12) and PC11 (13). 14, Ammodiscus peruvianus Berry, 1928, PC060617. 15-16, Ammodiscus cf. latus Grzybowski, 1898, PC11. 17, Ammodiscus sp. 1, PC11. 18, Ammodiscus sp. 2, PC15. 19, Ammodiscus sp. 3, PC060603. 20, Annectina biedai Gradstein and Kaminski, 1997, PC060618. 21, Annectina cf. grzybowski (Jurkiewicz, 1960), PC060617. 22, Glomospira sp. 2, PC15. 23, Glomospira sp. 1, PC11. 24, Glomospira sp. 3, PC13. 25-26. Glomospira serpens (Grzybowski, 1898), PC060617 (25) and PC060618 (26). 27, Glomospira irregularis (Grzybowski, 1898), PC060618. Scale bar equals 0.5 mm.