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
Globocassidulina subglobosa
(
Brady, 1881
)
Pl. 4, figs. 9–10
Cassidulina subglobosa
Brady, 1881
, p. 60
;
Brady, 1884
, p. 430
, pl. 54, fig. 17;
Barker, 1960
, pl. 54, fig. 17.
Globocassidulina subglobosa
LeRoy & Levinson, 1974
, p. 14
, pl. 7, fig. 8;
Tjalsma & Lohmann, 1983
, p. 31
, pl. 16, fig. 9;
Lowry, 1987
, p. 239
, pl. 14, figs. 7a–c;
Miller & Katz, 1987
, p. 134
, pl. 3, fig. 4;
Hermelin, 1989
, p. 74
;
Thomas, 1990
, p. 590
;
Jones, 1994
, p. 60
, pl. 54, fig. 17;
Robertson, 1998
, p. 136
, pl. 53, figs. 1–2;
Kuhnt
et al
., 2002
, p. 144
, pl. 10, figs. 3–5; pl. 17, figs. 1–2;
Kender
et al
., 2008
, p. 512
, pl. 17, fig. 1–2;
Milker & Schmiedl, 2012
, p. 85
, figs. 20.13–20.14;
Holbourn
et al
., 2013
, p. 264
.
Description
: The test wall is calcareous and smooth. The test is small, subglobular and subcircular in cross-section. The chambers have a biserial arrangement, are inflated and globular in shape, separated by depressed sutures. The aperture is slit-like, situated interio-marginal and stretches along the margin of the terminal chamber.
Remarks:
Specimens from this species comprise a trace component (<1%) in core 2658, a minor component (<5%) in core 2682 and major component (<40%) in core 2670. The tests from this study are smaller than those in
LeRoy & Levinson (1974)
(diameter of up to
0.75 mm
), measuring
0.25 mm
in diameter.
Life strategy:
This species is epifaunal to shallow-infaunal (
Kaiho, 1994
;
Vilela, 1995
), generally unattached and prefers muddy sediments under oxic (
Kaiho, 1994
) to suboxic (
De & Gupta, 2010
) conditions. Schmiedl
et al
. (1997) recorded
G. subglobosa
in oligotrophic areas, under vigorous bottom currents and sandy substrates.
Panieri & Gupta (2008)
recorded this species in relatively high abundances in muddy substrates. The bathymetric range of
G. subglobosa
is broad, stretching from the middle shelf to abyssal depths (
Murgese & de Deckker, 2005
;
Holbourn
et al
., 2013
).
Global stratigraphic range:
Globocassidulina subglobosa
occurs from the Palaeocene to Recent (
Holbourn
et al
., 2013
).
Regional occurrence
: This species is recorded in Miocene-aged strata from the
Congo
Basin (
Kender
et al.
, 2008
) and the Namibian outer continental shelf, south of the Kunene River mouth (this study).
Hay
et al.
(1984)
and
Wefer
et al
. (1998)
reported the occurrence of
Globocassidulina subglobosa
in
late Miocene
to Pleistoceneaged sediments along the continental slope in relatively minor abundances (<10%) at most sites.
Lowry (1987)
recorded occurrences of
G. subglobosa
in surface sediments on the continental shelf, between Cape Town and Port Elizabeth.