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 dutemplei
(
d’Orbigny, 1846
)
Pl. 6, figs. 2a–c
Rotalina dutemplei
d’Orbigny, 1846
, p. 157
, pl. 8, figs. 19–21.
Heterolepa dutemplei
Papp & Schmid, 1985
, p. 61
, pl. 52, figs. 1–6;
Loeblich & Tappan, 1988
, p. 632
, pl. 709, figs. 1–8;
Oblak, 2007
, p. 305
, pl. 4, figs. 2a–c;
Holbourn
et al.,
2013
, p. 294
–295.
Cibicidoides dutemplei
van Morkhoven
et al.,
1986
, p. 112
, pl. 35.
Description
: The test wall is calcareous and macroperforate. The test is trochospiral and mainly planoconvex in side view, with the umbilical side very convex. The earlier chambers form a slightly convex shape on the spiral side. The approximately eight chambers in the final whorl gradually increase in size toward the apertural end. The chambers are separated by flush, less perforate sutures, covering almost the entire earlier chambers of the inner whorl. The sutures on the spiral side are oblique. The aperture is an interio-marginal slit, extending along the inflated apertural chamber on the umbilical side.
Remarks:
Heterolepa dutemplei
is a minor (<5%) component in the samples of all three cores. Tests are relatively moderate to large in size, measuring up to
1 mm
in diameter.
Life strategy:
This species has a bathymetric distribution from the shelf to the upper slope (
van Marle, 1988
; Holbourn e
t al.,
2013), adapted to muddy substrates in organic-rich environments and oxic to suboxic conditions (e.g., Debenay-Redois, 1997;
Peryt, 2013
;
Rahiminejad
et al.,
2016
;
Roslim
et al.,
2019
).
Global stratigraphic range:
Heterolepa dutemplei
has been documented in Palaeocene (
Stojanova and Petrov, 2014
) to Recent strata (e.g.,
van Marle, 1988
; Szarek e
t al.,
2006).
Regional occurrence
: This study records
Heterolepa dutemplei
to occur in middle Miocene sediments on the outer continental shelf of
Namibia
, south of the
Kunene
River mouth.