Globigerinella siphonifera (d’Orbigny, 1839)

Ovechkina, Maria N., Bylinskaya, Marina E. & Uken, Ron, 2010, Planktonic foraminiferal assemblage in surface sediments from the Thukela Shelf, South Africa, African Invertebrates 51 (2), pp. 231-231 : 243

Globigerinella siphonifera (d’Orbigny, 1839)

Figs 7A, 7B, 7D, 7E

Globigerina siphonifera: d’Orbigny 1839 a: 83 , pl. 4, figs 15–18.

Globigerina aequilateralis Brady, 1879: 285 ; 1884: 605, pl. 80, figs 18–21.

Globigerinella aequilateralis (Brady) : Cushman 1927 a: 87; Todd 1965: 64–65, pl. 25, figs 4, 5; Saito et al.

1976: 281–282, pl. 3. figs 1, 2; pl. 6, fig. 7; pl. 8, figs 3, 8; 1981: 26, pl. 2, figs 2a–d; Bolli & Saunders

1985: 253, figs 42.6; 43.5–7, 9, 10; Loeblich & Tappan 1987: 489, pl. 535, figs 8–12; Cimerman &

Langer 1991: 57, pl. 60, figs 4, 5.

Hastigerina siphonifera (d’Orbigny) : Bolli & Saunders 1985: 251, figs 42.1, 4; 43.1, 2, 8.

Globigerinella siphonifera (d’Orbigny) : Parker 1962: 228, pl. 2, figs 22–28; Loeblich & Tappan 1994: 106,

pl. 200, figs 7–10; pl. 201, figs 1–3; Bylinskaya et al. 2002: 125, pl. I, figs 1–3.

This species is very variable, with the test varying from very low trochospiral to planispiral. The test is medium to large. Chambers are spherical to ovate, rapidly enlarging in the adult whorl. Sutures distinct and depressed. The aperture appears as a low, wide symmetrical equatorial arch in the interiomarginal position.

Remarks: G. siphonifera is more hispid than Hastigerina pelagica , and more tightly coiled and planispiral than Globigerinella calida .

Distribution: Tropical – subtropical waters. It appears in practically all our samples, in low abundance.

Figures

Fig. 7. (A, D) Globigerinella siphonifera (d’Orbigny, 1839), sample 26; (B, E) G. siphonifera, another specimen from sample 26; (C, F) Globigerinoides bulloideus Crescenti, 1966, sample 30; (G–I) Globigerinoides tenellus Parker, 1958, sample 6.