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
Heterolepa broeckhiana
(
Karrer, 1878
)
Pl. 6, figs. 3–4
Rotalina broeckhiana
Karrer, 1878
, p. 98
, pl. 5, fig. 26.
Gyroidina broeckhiana
Belford, 1966
, pp. 167, 168, pl. 29, figs. 1–7, text-figs. 21–10, 21–11;
Jones, 1994
, p. 106
, pl. 107, fig. 4.
Description
: The test wall is calcareous and microperforate. The test is trochospiral, subcircular in outline and unequally biconvex in side view and in cross-section. Approximately six to eight chambers are visible externally in the final whorl. The chambers gradually increase in size toward the terminal apertural end and are separated by slightly depressed sutures. The sutures on the spiral side are radial and straight on the umbilical side. The aperture is an extraumbilical to interio-marginal slit.
Remarks:
The relative abundances of this species are moderate to high (<10%) in the three cores. Tests in this study are relatively large, measuring up to
1 mm
in diameter.
Life strategy:
The genus
Heterolepa
has a shelf to upper slope distribution in well oxygenated environments (Rögl and Spezzaferri, 2003).
Regional occurrence
: This study is the first to document this species in midddle Miocene strata in the region and occurs on the Namibian outer continental shelf, south of the
Kunene
River
mouth (this study).