Globigerinoides, Cushman, 1927

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 : 248

Key to the species of Globigerinoides from the Thukela Shelf

1 Test very loosely embracing, with 4–5 subglobular slightly flattened chambers in final whorl; last chamber completely detached from previous whorl ( Figs 9D, 9E ).......................................................................................aberrant form of ruber

– Test not so loosely embracing or sometimes closely embracing, with at most 4 globular chambers in final whorl; last chamber at least partly attached to previous whorl......................................................................................................................2

2 Chambers in final whorl greatly embracing...........................................................3

– Chambers in final whorl partly embracing or non-embracing...............................4

3 Test small with 4 globular chambers in final whorl .................................... tenellus

– Test large or medium with 3.5 subspherical chambers in final whorl...................... ............................................................................................................. conglobatus

4 One small secondary aperture................................................................ bulloideus

– More than one secondary aperture.........................................................................5

5 Primary aperture characteristically drop-shaped, situated symmetrically above suture between 2 previous chambers................................................................. ruber

– Primary aperture as low, quite wide symmetrical interiomarginal arch.................6

6 Final chamber globular .............................................................................. trilobus

– Final chamber subglobular, sac-like........................................................ sacculifer

Figures

Fig. 9. (A, B) Globigerinoides ruber (d’Orbigny, 1839), sample 22; (C) G. ruber, sample TB34; (D, E) G. ruber (aberrant form),sample 8; (F, G) Sphaeroidinella dehiscens (Parker &Jones,1865), sample 30; (H) Orbulina universa (d’Orbigny, 1839), sample C.