Nephrolepidina praemarginata ( Douvillé, 1908 )

Gedik, Fatma & Karadenizli, Levent, 2021, Oligocene larger benthic foraminifera and sedimentation of the Burdur Basin, SW Anatolia, Turkey, Geodiversitas 43 (13), pp. 377-389 : 383

Nephrolepidina praemarginata ( Douvillé, 1908) ( Fig. 5 D-G)

Lepidocyclina praemarginata Douvillé, 1908: 91-92 , figs 1, 2, 4a.

Nephrolepidina praemarginata – Douvillé 1924: 51-123, pl. 6, figs 4, 6. — Gomez Llueca 1929: 1-400, pl. 32, figs 4-10. — Flandrin 1935: 251-272, pl. 15, figs 14-18. — Poignant 1967: 197-211, pl. V, fig. 2. — Gedik 2014: 101, pl. 6, figs 1-14.

REMARKS

The identification is based only upon axial sections. The small test is inflated, lenticular with a central umbo, so that the shell is thicker towards the center. The diameter of the test ranges from 1.5 to 2.1 mm and the thickness from 0.6 to 0.9 mm. The large, central umbo consists of numerous small pustules ( Fig. 5E, G ). Lateral chambers are numerous at the surface of test and rosette shaped, and this feature forms a comb-like surface appearance ( Fig. 5E ). The embryo consists of subspherical small protoconch (diameter 0.25 mm) and reniform deuteroconch (diameter 0.22 mm). Secondary chambers are very small and their sizes are almost equal to each other. The equatorial chambers are subrectangular or rhombic in outline. There are 6-7 orders of lateral chambers in the center of the test.

Figures

FIG. 5. — A, B, Operculina complanata (Defrance, 1822); A, equatorial section, İl-6C/2; B, incomplete equatorial section, İl-6B/2; C, J, Nummulites fichteli Michelotti, 1841; C, external view, İl-6C/3; J, axial section, megalospheric form, İl-6A; D-G, Nephrolepidina praemarginata (Douvillé, 1908); D, axial section, İl-6A; E, external view, İl-6B/4; F, axial section, megalospheric form, İl-6C/1; G, axial section, İl-6B/2. H, I, Eulepidina sp., subaxial sections, İl-6A, İl-6B/5. Scale bars: A, 1 mm; B, D-G, L, 0.5 mm; C, I, J, 2 mm.