Taxonomy of Middle Miocene foraminifera from the northern Namibian continental shelf
Author
Bergh, Eugene W.
0000-0002-0765-4141
Marine Research Institute and Department of Geological Sciences, University of Cape Town, Private Bag X 3, Rondebosch, 7701, South Africa. & Department of Environmental and Geographical Sciences, University of Cape Town, Private Bag X 3, Rondebosch, 7701, South Africa; & Invertebrate palaeontology and Geology, Iziko South African Museum, P. O. Box 61, Cape Town 8000, South Africa. john. compton @ uct. ac. za; https: // orcid. org / 0000 - 0002 - 0765 - 4141
john.compton@uct.ac.za
Author
Compton, John S.
Marine Research Institute and Department of Geological Sciences, University of Cape Town, Private Bag X 3, Rondebosch, 7701, South Africa.
text
Zootaxa
2022
2022-01-12
5091
1
1
55
journal article
2636
10.11646/zootaxa.5091.1.1
51b42715-ddb1-4b4a-aad4-8be0f600a287
1175-5326
5840434
ABC8AF70-F691-4D07-8F20-70934642C8BC
Globigerina concinna
Reuss, 1850
Pl. 7, figs. 7-8
Globigerina concinna
Reuss, 1850
, p. 373
, pl. 47, fig. 8;
Cushman and Stainforth, 1945
, pl. 13, fig. 1;
Bolli
et al
., 1985
, p. 321
, fig. 4.17–20.
Description
: The wall surface is cancellate spinose. The test is trochospirally arranged, with five globular chambers in the final whorl. The sutures are straight and depressed. The aperture is large and umbilical.
Remarks:
The relative abundance of
G. concinna
in this study is trace (<1%) in samples of all three cores. The tests are relatively moderate in size, measuring up to
0.5 mm
in diameter.
This species is similar to an older form,
Ciperoella ciperoensis
(previously
Globigerina ciperoensis
), but differs in its size, chambers and aperture. The chambers of
G. concinna
increase in size more rapidly and its test is generally larger compared to
C. ciperoensis
. The aperture of
G. concinna
is also larger and more asymmetrical than
C. ciperoensis
. The two species, furthermore, occur in different stratigraphic ranges.
C. ciperoensis
occurs in the Oligocene, whereas
G. concinna
occurs in middle Miocene strata (
Bolli
et al
., 1985
).
Environmental preferences:
Species in the
G. concinna
group is regarded to be adapted to tropical and subtropical conditions (
BouDagher-Fadel, 2015
).
Global stratigraphic range:
G. concinna
has been documented to occur from the Burdigalian in the early Miocene to the Serravallian in the middle Miocene (
BouDagher-Fadel, 2015
).
Regional occurrence:
This study records the first, and to date, only occurrence in the region of this species in the middle Miocene of the
northern Namibian
continental shelf, south of the
Kunene
River
mouth (this study)
.