y if ASL ; hk VOLUME 103 PART 7 MARCH 1994 ISSN 0303-2515 Nit WiTMSON ay JUN 10 1994, ANNALS OF THE SOUTH AFRICAN — ~~ MUSEUM CAPE TOWN INSTRUCTIONS TO AUTHORS 1. MATERIAL should be original and not published elsewhere, in whole or in part. 2. LAYOUT should be as follows: (a) Centred masthead to consist of Title: informative but concise, without abbreviations and not including the names of new genera or species Author’s(s’) name(s) Address(es) of author(s) (institution where work was carried out) Number of illustrations (figures, enumerated maps and tables, in this order) (b) Abstract of not more than 200 words, intelligible to the reader without reference to the text (c) Table of contents giving hierarchy of headings and subheadings (d) Introduction 6 (e) Subject-matter of the paper, divided into sections to correspond with those given in table of contents (f) Summary, if paper is lengthy (g) Acknowledgements (h) References (i) Abbreviations, where these are numerous. 3. MANUSCRIPT, to be submitted in triplicate, should be typewritten and neat, double spaced with 3 cm margins all round. First lines of paragraphs should be indented. Tables and a list of captions for illustrations should be typed separately, their positions indicated in the text. All pages should be num- bered consecutively. Major headings of the paper are centred capitals; first subheadings are shouldered small capitals; second subheadings are shouldered italics; third subheadings are indented, shouldered italics. Further subdivisions should be avoided, as also enumeration (never roman numerals) of headings and abbreviations. Footnotes should be avoided unless they are short and essential. Only generic and specific names should be underlined to indicate italics; all other marking up should be left to editor and publisher. 4. ILLUSTRATIONS should be reducible to a size not exceeding 12 x 18 cm (19 cm including caption); the reduction or enlargement required should be indicated (and preferably uniform); orig- inals larger than 35 x 47 cm should not be submitted; photographs should be rectangular in shape and final size. A metric scale should appear with all illustrations, otherwise magnification or reduction should be given in the caption; if the latter, then the final reduction or enlargement should be taken into consideration. All illustrations, whether line drawings or photographs, should be termed figures (plates are not printed; half-tones will appear in their proper place in the text) and numbered in a single series. Items of composite figures should be designated by capital letters; lettering of figures is not set in type and should be in lower-case letters. If Letraset is used authors are requested to use Helvetica-style letter- ing, if possible. The number of the figure should be lightly marked in pencil on the back of each illustration. 5. REFERENCES cited in text and synonymies should all be included in the list at the end of the paper, using the Harvard System (ibid., idem, loc. cit., op. cit. are not acceptable): (a) Author’s name and year of publication given in text, e.g.: ‘Smith (1969) describes . . .” ‘Smith (1969: 36, fig. 16) describes...” ‘As described (Smith 1969a, 19695; Jones 1971)’ “As described (Haughton & Broom 1927) .. .” ‘As described (Haughton ef a/. 1927)...” Note: no comma separating name and year pagination indicated by colon, not p. names of joint authors connected by ampersand et al. in text for more than two joint authors, but names of all authors given in list of references. (b) Full references at the end of the paper, arranged alphabetically by names, chronologically within each name, with suffixes a, b, etc., to the year for more than one paper by the same author in that year, e.g. Smith (1969a, 1969b) and not Smith (1969, 1969a). For books give title in italics, edition, volume number, place of publication, publisher. For journal article give title of article, title of journal in italics (according to the World list of scientific periodicals. 4th ed. London: Butterworths, 1963), series in parentheses, volume number, part number in parentheses, pagination (first and last pages of article). Examples (note capitalization and punctuation) Bu LiouGnH, W. S. 1960. Practical invertebrate anatomy. 2nd ed. London: Macmillan. FiscHER, P. H. 1948. Données sur la résistance et de la vitalité des mollusques. Journal de conchyliologie 88 (3): 100-140. FiscHER, P. H., Duvat, M. & Rarry, A. 1933. Etudes sur les échanges respiratoires des littorines. Archives de zoologie expérimentale et générale 74 (33): 627-634. Koun, A. J. 1960a. Ecological notes on Conus (Mollusca: Gastropoda) in the Trincomalee region of Ceylon. Annals and Magazine of Natural History (13) 2 (17): 309-320. Koun, A. J. 19606. Spawning behaviour, egg masses and larval development in Conus from the Indian Ocean. Bulletin of the Bingham Oceanographic Collection, Yale University 17 (4): 1-51. THIELE, J. 1910. Mollusca. B. Polyplacophora, Gastropoda marina, Bivalvia. In: SCHULTZE, L. Zoologische und anthro- pologische Ergebnisse einer Forschungsreise im westlichen und zentralen Stid-Afrika ausgefiihrt in den Jahren 1903-1905 4 (15). Denkschriften der medizinisch-naturwissenschaftlichen Gesellschaft zu Jena 16: 269-270. (continued inside back cover) ANNALS OF THE SOUTH AFRICAN MUSEUM ANNALE VAN DIE SUID-AFRIKAANSE MUSEUM Volume 103 °+#Band March 1994 Maart Part 7 Deel QUATERNARY OSTRACODS FROM THE CONTINENTAL MARGIN OFF SOUTH-WESTERN AFRICA. PART HI. OCEANOGRAPHICAL AND SEDIMENTARY ENVIRONMENTS By R. V. DINGLE Cape Town Kaapstad The ANNALS OF THE SOUTH AFRICAN MUSEUM are issued in parts at irregular intervals as material becomes available Obtainable from the South African Museum, P.O. Box 61, Cape Town 8000 Die ANNALE VAN DIE SUID-AFRIKAANSE MUSEUM word uitgegee in dele op ongereelde tye na gelang van die beskikbaarheid van stof Verkrygbaar van die Suid-Afrikaanse Museum, Posbus 61, Kaapstad 8000 OUT OF PRINT/UIT DRUK 1, 2(1-3, 5-8), 3(1-2, 4-5, 8, t.-p.i.), 5(1-3, 5, 7-9), 6(1, t.-p.i.), 711-4), 8, 911-2, 7), 10(1-3), 11(1-2, 5, 7, t.-p.1.), 14(1-3), 15(4-5), 24(2, 5), 27, 31(1-3), 32(5), 33, 36(2), 43(1), 45(1), 67(5, 11), 84(2) Copyright enquiries to the South African Museum Kopieregnavrae aan die Suid-Afrikaanse Museum ISBN 0 86813 151 2 Printed in South Africa by In Suid-Afrika gedruk deur The Rustica Press, Pty., Ltd., Die Rustica-pers, Edms., Bpk., Old Mill Road, Ndabeni, Cape Old Mill-weg, Ndabeni, Kaap D2700 QUATERNARY OSTRACODS FROM THE CONTINENTAL MARGIN OFF SOUTH-WESTERN AFRICA. PART III. OCEANOGRAPHICAL AND SEDIMENTARY ENVIRONMENTS By R. V. DINGLE Micropalaeontology Research Unit, South African Museum, Cape Town (With 34 figures and 7 tables) [MS accepted 7 December 1992] ABSTRACT The distribution of benthic Ostracoda on the continental shelf and upper slope between Cape Agulhas and the Kunene River is shown to be related to various time-averaged oceanographical and sedimentary parameters. The microfossils represent mixed modern and relict assemblages, probably dating from Recent to late Holocene time (c. 7000 yr Bp.). For each of the 36 most abundant species (> 95% of the total ostracod assemblage, with 123 species) mean values for a range of environmental sea-floor parameters have been calculated. These relate to water properties (temperature, salinity, dissolved oxygen) and substrate characteristics (sand, mud, calcium carbonate, total organic matter, elemental Fe and authigenic mineral contents). Correlation coefficients between these parameters and individual species indicate which parameters are the most important in determining distributions. On a regional scale, the various areas of the continental shelf are dominated by a particular species. North of about 24°S, upwelling-induced low dissolved oxygen and high total organic matter (MORG) values favour Cytherella namibensis (outer shelf) and Palmoconcha walvisbaiensis (inner to mid-shelf), respectively. Farther south, the influence of advected, well-oxygenated Antarctic Intermediate Water on to the uppermost slope and outer shelf controls the distribution of Ruggieria cytheropteroides, whereas on the mid- and inner shelf, variations in mud and terrigenous components are the main controls for Pseudo- keijella lepralioides and Bensonia knysnaensis knysnaensis, respectively. In water deeper than about 500 m, the dominant species along the whole margin is Henryhowella melobesioides, whose distribution is primarily controlled by temperature/salinity variations. (Closer inshore, mud content of bottom sediments is more important.) For the other most abundant species, the main environmental controls are substrate- dominated, with sand and calcium carbonate (mainly negative) the most important. Elemental Fe (which is used as a gauge of the terrigenous component) is also important (both positively and negatively), with total organic matter more frequently important than any of the bottom-water properties. Barren areas (sparse or no ostracod faunas) occur in both shallow and deep water, and are associated with the effects of upwelling (north of 27°S), fluvial terrigenous input (Namaqualand inshore area), and isolation from sources of terrigenous and organic matter (either side of the Cape Canyon). CONTENTS PAGE EMCO CUICELO Tse ers a ira eine oO GE EMCI ote eee ata 384 JSeGTPL IIS reisics Bl ees cuca ach oe certain ey ER eae ict Cf RM ToC Aa age 389 Bhysicaltoceanoprap hyn re vasiecnac ey oie eat ae eee 393 Bottommsedimentsiand seochemistnye mer ter eerie ia ae ea 406 BRO pUlatrony structure peer ee. oe eee eee eae to eRe ae eee 411 [SENSI RE NN) eH Ns cata roth o EEO O CULO Pee o Opa Ha b.OOe ceo ou oly ere 413 DY ISCUSSIOTUR eee der a ECE ie dart Maa eens 417 LLINTITTE Ey AGie erg Se 01k Dae ORE oS CAPA Cn aOR mon I Rar te) de DR a IANS hae ary 428 ACKHOWICASEIIEIS Myce eee Ceres n aR ee Ee ee: 431 FRCLETEMICES eet ayeae CRT Ra ate ese nce he OH Re RIO rnc AU NAL 432 Jo of {AA ONDC 1S Petre heehee ey Geet, ola eres Ce es AE RnR, COREE Ae tet EE Red 435 383 Ann. S. Afr. Mus. 103 (7), 1994: 383-441, 34 figs, 7 tables. 384 ANNALS OF THE SOUTH AFRICAN MUSEUM INTRODUCTION The taxonomy of the benthic Ostracoda from the continental shelf and upper slope off south-western Africa has been documented in parts I and II of this study (Dingle 1992, 1993). These supplemented earlier localized accounts by Brady (1880), Miller (1908), Klie (1940), Benson & Maddocks (1964) and Hartmann (1974). In the present paper, aspects of the distribution of the whole fauna will be assessed in relation to various environmental parameters of the bottom waters and sediments. Ostracoda were isolated from 270 sea-floor sediment samples collected between Cape Agulhas and the Kunene River in water depths between 15 m and 950 m (Fig. 1). A total of 123 species, belonging to 54 genera, was recorded (Table 1). The sediment samples were collected during the period 1967—1985 from the University of Cape Town’s R.V. ‘Thomas B. Davie’ by personnel of the joint Geological Survey/University Marine Geoscience Unit. The regional oceanography off south-western Africa has been summarized by Hart & Currie (1960), Stander (1964), Shannon (1966, 1985), Chapman & Shannon (1985), Lutjeharms & Meeuwis (1987), Shannon & Hunter (1988) and Shannon et al. (1990), amongst others. Briefly, the essential elements consist of a three-layer deep-water configuration that abuts the continental margin (Antarctic Bottom Water (AABW), North Atlantic Deep Water (NADW) and Antarctic Intermediate Water (AAITW)) and a mixed layer on the continental shelf (Fig. 2). The latter has several complexly related components, and is subject to considerable variability. Surface waters for the most part emanate from the South Atlantic gyre and move in a northerly direction, more or less parallel to the coast. This is the main component of the Benguela Current, and strong wind stress over it results in quasi-permanent regions of subsurface upwelling of varying intensity (e.g. Lutjeharms & Meeuwis 1987). Other major features are the intrusion of sub-tropical Angola Current water adjacent to the north coast, typically as far south as 18°S, and periodic intrusions of vortices and filaments of warm Agulhas Current water around the southern tip of the Agulhas Bank from the western part of the Agulhas Retroflexion (e.g. Shannon et al. 1990). The latter typically extend no farther north than about 33°S, although there has been considerable debate on their role in large-scale transfer of warm South-Western Indian Ocean water into the central Atlantic (e.g. Gordon & Haxby 1990). Southward subsurface movement of shelf water has been documented by De Decker (1970) and Nelson (1989) along most of the west coast, whereas north of 25°S several authors have postulated a southward moving current just below the shelf break that transfers oxygen-deficient water from the Angola Basin (Hart & Currie 1960; Stander 1964; Chapman & Shannon 1985). Sediment samples used in this study were collected using a Van Veen grab, which typically penetrates 10cm beneath the sediment—water interface. Ostracod valves were separated using standard washing and picking techniques, and faunas were examined from > 125 nw size fractions. No physical oceanographical measurements were collected from the sample sites but, because of the mixed Recent—subrecent nature of the ostracod assemblages, this omission is not critical to the study. Long-term mean values of parameters at each site were obtained in two ways: by averaging bottom-water data in quarter-degree squares around QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 385 WWALVIS BAY LUDERITZ Orange River Fig. 1. Bathymetry of the continental margin off south-western Africa with sediment sample sites indicated. e = ostracod-bearing, 0 = barren samples, WR = Walvis Ridge, OB = Orange Banks, CB = Childs Bank, CC = Cape Canyon. 386 ANNALS OF THE SOUTH AFRICAN MUSEUM TABLE | Species of Ostracoda recorded from the west-coast continental shelf. Species are listed alphabetically. Species Novos specimens * Ambostracon (A.) flabellicostata (Brady, 1880) 490 * Ambostracon (A.) keeleri Dingle, 1992 1 022 Ambostracon (A.) levetzovi (Klei, 1940) 19 Ambostracon sp. 3553 1 Ambostracon sp. 3571 2 Ambostracon (Patagonacythere) sp. 3556 14 Argilloecia sp. 3483 14 Aurila kliei Hartmann, 1974 44 * Australoecia fulleri Dingle, 1993 96 Australoecia sp. 3550 1 * Austroaurila rugosa Dingle, 1993 91 * Bairdoppilata simplex (Brady, 1880) 435 ?Basslerites (Loculiconcha) sp. 3444 2 Bathycythere vanstraateni Sissingh, 1971 1 * Bensonia k. knysnaensis Benson & Maddocks, 1964 Shit * Bensonia k. robusta Dingle, 1992 43 Bradleya cf. B. dictyon (Brady, 1880) 1 Bradleya (?Quasibradleya) sp. 3568 8 * Buntonia bremneri Dingle, 1993 79 * Buntonia deweti Dingle, 1993 8 * Buntonia gibbera Dingle, 1993 39 * Buntonia namaquaensis Dingle, 1993 37. * Buntonia rogersi Dingle, 1993 46 * Buntonia rosenfeldi Dingle, Lord & Boomer, 1990 47 Buntonia sp. 3486 2 Bythocythere sp. 3349 7 Caudites sp. 3329 2) * Chrysocythere craticula (Brady, 1880) 358 * Coquimba birchi Dingle, 1993 86 * Cytherella dromedaria Brady, 1880 702 * Cytherella namibensis Dingle, 1992 422 Cytherelloidea compuncta Dingle, 1993 ?Cytherois sp. 3538 Cytheropteron cuneatum Dingle, 1993 Cytheropteron frewinae Dingle, 1993 Cytheropteron aff. C. frewinae Dingle, 1993 * Cytheropteron trinodosum Dingle, 1993 Cytheropteron whatleyi Dingle, 1993 Cytheropteron sp. 2878 Cytheropteron sp. 2881 Cytheropteron sp. 2882 Cytheropteron sp. 2902 Cytheropteron sp. 3406 Cytherura siesseri Dingle, 1993 * Doratocythere exilis (Brady, 1880) Doratocythere sp. 3584 ?Falklandia sp. 3546 Hemicytherura petheri Dingle, 1993 Hemicytherura sp. 3393 ?Hemicytherura sp. 3404 i on ON Ww NR DR NORK KH WN REDD RRP RR NOMNeE MB YE * Henryhowella melobesioides (Brady, 1869) 42 * Incongruellina venusta Dingle, 1993 9 Kangarina hendeyi Dingle, 1993 Kangarina mucronata (Brady, 1880) 3 Kangarina sola Dingle, 1993 Kangarina? sp. 3439 * Krithe capensis Dingle, Lord & Boomer, 1990 143 * Krithe spatularis Dingle, Lord & Boomer, 1990 12 Krithe sp. 8 Dingle, Lord & Boomer, 1990 11 Krithe sp. 9 Dingle, Lord & Boomer, 1990 12 Kuiperiana angulata Dingle, 1992 62 ?Kuiperiana sp. 3320 2 QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 387 TABLE | (cont.) . No. of SISSIES specimens Macrocypria sp. 3471 >) * Macrocypris cf. M. metuenda Maddocks, 1990 102 Meridionalicythere petricola (Hartmann, 1974) 13 ?Meridionalicythere sp. 3581 4 Munseyella eggerti Dingle, 1993 36 Mutilus bensonmaddocksorum Hartmann, 1974 2 Mutilus malloryi Dingle, 1993 17 * Neocaudites lordi Dingle, 1993 25 * Neocaudites osseus Dingle, 1993 142 Neocaudites punctatus Dingle, 1993 7, * Neocytherideis boomeri Dingle, 1992 511 Palmoconcha subrhomboidea (Brady, 1880) 39 * Palmoconcha walvisbaiensis (Hartmann, 1974) 475 ?Palmoconcha walvisridgensis Dingle, 1992 >) * Paracypris lacrimata Dingle, 1992 533 Paracytheridea sp. 3339 1 Paradoxostoma griseum Klie, 1940 4 Paradoxostoma aff. P. auritum Klie, 1940 23 Paradoxostoma aff. P. luederitzensis Hartmann, 1974 16 Parakrithella simpsoni Dingle, 1993 68 ?Parakrithella sp. 3468 2 * Poseidonamicus panopsus Whatley & Dingle, 1989 Ay Propontocypris cf. P. (P.) subreniformis (Brady, 1880) 66 Propontocypris (?P.) sp. 3345 2 Propontocypris (?Ekpontocypris) sp. 3434 1 Propontocypris (?Schedopontocypris) sp. 3535 i * Pseudokeijella lepralioides (Brady, 1880) 8 181 ?Quadracythere sp. 3333 12 * Ruggieria cytheropteroides (Brady, 1880) 5 298 Semicytherura clausi (Brady, 1880) | Semicytherura sp. 3379 I Semicytherura sp. 3382 4 Semicytherura sp. 3385 5 Semicytherura sp. 3414 4 Stigmatocythere sp. 3479 a Trachyleberis sp. 3586 il * Urocythereis arcana Dingle, 1993 166 ?Urocythereis sp. 3310 2 ?Urocythereis sp. 3472 1 ?Urocythereis sp. 3567 2 ?Urocythereis sp. 3570 1 * Xestoleberis africana Brady, 1880 500 Xestoleberis capensis Miller, 1908 * Xestoleberis hartmanni Dingle, 1992 Xestoleberis ramosa Miller, 1908 Xestoleberis sp. 3398 Xestoleberis sp. 3524 Indet. sp. 3306 Indet. sp. 3308 Indet. sp. 3343 Indet. sp. 3412 Indet. sp. 3426 Indet. sp. 3429 Indet. sp. 3447 Indet. sp. 3481 Indet. sp. 3539 Indet. sp. 3543 Indet. sp. 3568 Indet. sp. 3574 Indet. sp. 3576 Indet. sp. 3578 i) ie) i N me SND SE OO RR eS SE ELD OD *—thirty-six most-abundant species; these account for more than 95 per cent of total population, and have been used for most of the statistical analyses. 388 ANNALS OF THE SOUTH AFRICAN MUSEUM Angola Current } Walvis Bay Luderitz Warm water } Cape Town N f \ Main centres —_ A ee \ of upwelling — OE !) ‘\C. Agulhas Shelf break Benquela flow line Axis of Walvis Ridge Agulhas Retroflexion Fig. 2. Main oceanographical elements in relation to the position of the continental shelf edge off south-western Africa. Based on Shannon (1985), Lutjeharms & Meeuwis (1987) and Lutjeharms (1989). AAIW = Antarctic Intermediate Water, NADW = North Atlantic Deep Water, AABW = Ant- arctic Bottom Water, SMZ = salinity minimum zone, CCD = carbonate compensation depth, ¢ = southward motion, 6 = northward motion. QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 389 sample sites, and by reading values at sites from regional maps constructed specifically for the purpose. Physical oceanographical data were obtained from the South African Data Centre for Oceanography (SADCO), for temperature and salinity, and Sea Fisheries Research Institute, for dissolved oxygen. Dingle & Nelson (1993) provided a preliminary account of the bottom temperature, salinity and dissolved oxygen distributions, as well as details of the data processing and reliability. Briefly, this consisted of screening the 30000 SADCO records to obtain 2 869 temperature and salinity readings. To construct regional maps, these measurements were averaged in 391 quarter-degree rectangles over the west- coast continental margin. A similar technique was used to produce | 314 bottom-water dissolved-oxygen values, which were combined with results from the survey of De Decker (1970). ; The texture and geochemistry of sea-floor sediments on the margin between the Kunene River and Cape Agulhas have been analysed in three doctoral theses by Birch (1975), Rogers (1977) and Bremner (1981). These workers used the same set of samples as in the present study. Their results have been summarized and refined in Birch et al. (1986), Bremner er a/. (1986) and Rogers & Bremner (1991). Additional analytical details of the sedimentary geochemistry off Namibia have been presented by Bremner (1980, 1983) and Bremner & Willis (1993). Geochemical and textural data for each site utilized in the present study were extracted from these publications, either as analyses of specific sediment samples or extractions from regional contoured maps. Reference should be made to Birch (1975), Rogers (1977) and Bremner (1981) for details of analytical techniques. Elemental analyses were performed on the < 63 y fractions of sediments, which Bremner & Willis (1993) have shown provide a good estimation of overall sediment geochemistry. RESULTS Descriptive statistics (means, standard deviations and ranges) and Pearson product- moment correlation coefficient analyses have been performed on the 36 most abundant species of ostracods for a variety of environmentally relevant parameters (Table 2). The latter relate to the physical oceanography (bottom-water temperature, salinity and dissolved oxygen, water depth and geographic latitude) and nature of the bottom sediments (organic matter, texture and elemental geochemistry). The most abundant species account for 95.47 per cent of the total available ostracod fauna, and are illustrated in Figures 3—S. These results allow me to supplement the distributional data presented in Parts I and II (Dingle 1992, 1993). The numerical data presented in the Appendix comprise what I believe to be a unique published compilation of environmental information for a modern ostracod fauna from such a large area of continental shelf (approximately 420 000 km/7). The correlation coefficients are used to supplement and highlight relationships between and within elements of the fauna. It should be remembered that strong corre- lation coefficients indicate which species are most strongly influenced (positively or negatively) by changes in the parameters and will not necessarily be those that have the highest (or lowest) mean values. In this sense, the correlation coefficient is a measure of ANNALS OF THE SOUTH AFRICAN MUSEUM 390 6L6S'0;~ 0860 c0r70; LOtCCO 617290 S8cS 0 9r61°0 = = DUDIUJO S1daga]OISaX as 8LtL 0 c0cs 0 p8S1°0 = = = == — DUDIAD SlaLAYINIOAN) = = — = — = 9061 °0 = = SaplOda}dOAIYINI DIAIBSNY — = = a 9rsp O° ctrl 0 orsp'O- Ol8eO 8 6rS'0 SISUIDIDGSIAJDM DYDUOIOU] Dd == = 8899 0 €99¢'0- = SST7'0 = 9L61'0 — — snsdouvd snonunuoplasod zbZE0- OOLZ'0- Was 008Z'0- aes 908Z'0 =— — — sapioupsda] djjafiayopnasd 66070" =: 97870 v197 0 l6lIr0 =976S"0 S697 0 a y907 0- = DIDUMID] SIMAKOADIDd C8ELO- =: 8979 0——s«BLLBH' 867C 0 a 7990 4 tL6l 0 69SP'0- SNISSO SJOPMIYINIOON 61ct 0 OGSiOn = 06230 S190; LOLI 0, ~~ £9ES:0 p9s9'0- = SZI7 0 pc0e 0 [PAO] SIOPMOYINIOON €tc9'0 = =a P9810 CS87 0 OL87'0- == SOcL O- a LIUO00G SIAPMOYINIOAN Cres 0 a ae L616°0 SOOT 0 c6$9'0° — SOLI 0- a ZELI'O «= Dpuaniaw “PW “49 SUdKo4Dy GyEGOn = Le0veO= 0S8C Os “OIL Or GLECOr ESSTiO= ~ 86EC'0; == 6L17 0" DISNUAA DUI]JANASUODUT 660S 0 IpIpoO = ISLI0 180S'0° t61 0 OLLY'O" = S6L70 ay LII¢ 0 SAPlOISAGO]AUl Dj]IMOYMUIH L681 °0 8r97 0 OgeCi0e LZOTE0 — $997 0° = $7770 LOLt'0 OPC 0" STIXO ALOYINIOIDAOG S80 899 0= “9SO0V0: — L797 ‘07 = OOLEOn = FStT Oo b7ESO 6012'0 8SL7'0 pele 0 SISUIGNUDU DIJALOYIND IssS0O- 6P9T 0 — LLLTO" aaa SI81°0 97IS'0 <= l6se'O° = OLS 10" DIADPAUOAP D]JAAIYIN = IL07'0 09910" Iv77'0 O8 PT 07 = — — — DINIHDAD AAOYIKIOSKAYD, LO8Y 0 1100) al On 7 OCG OO 7a ISpr'0 LOSt'0- = ELSI'0 967 0 a xajduis piojiddopalog €Se7 O- = GUEGOs eLSSS0m “CCCI0= = alGSi0 CSEG0e COTO VLOLSI0; ISd004 DIUOJUNG cere 0 Ofc6'0 Or66'0 6L19'0° =680L 0° =e l0E 0 ~— 88 L'0 9699°'0- 8 PL9'0- SISUDGIUDU DIUOJUNG L7r0- 00880 60180 9Fr8O 66160 = 108S°0 <= p907'0 SISUIDUSAUY “Y DIUOSUAg 66c9 0" a 69170 = 98780 6977 0 6889 0 p98 0 pS69 0 97970 Dlagqis Dluojung CCpL OO” =—s« SL8V'O”—s«sETBEO =F CBLPO 8 S9LS'0 OOILO ce ot 0 = 96L7'0 MaUululadg DIUOJUNG 91060 O19S0 P9tPr'0 7676 0 O8tr'O LPrLL oO 180¢°0 607 0 87Sb 0 DSOONA D/LANDOAISAY = COIS ‘0 L6lr'0 vol! '0 £8090 = = = aa Ma]nf DIDAO|DAISNY 6rce 0 = OO FE O- = (GAG = OLOF 0 a 6SL70° S061 0- 10/004 UOIDAISOQUIY OlSsr'O = chev 0 971 0 — 9SLt 0 = c6S1'0 9ELS'0 8676 0 DIDISOI]AqD]f UOIDLISOGUIY pues anedy one] f99Rr9 o4 QYOW uaskxQ — Ajiuryes ‘dway “paist] ase (QOS| OQ <) aouvoyiusis judd Jad 66 < suONRIa1I09 A[UO GeUEKAL “SA[QRIIRA pue Saloads udaMIAq S}JUDIOIYJ909 UOIR|AIIOD QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 39] Fig. 3. Most abundant ostracod species on the continental shelf off south-western Africa arranged in order of latitudinal centre of distribution (mean of all observed sites, see Figure 6). Vertical bars are degrees of latitude (S); horizontal scales = 100 wu. A = Palmoconcha walvisbaiensis, B = Bensonia k. robusta, C = Cytherella namibensis, D = Neocaudites lordi, E = Incongruellina venusta, F = Buntonia rogersi, G = Krithe spatularis, H = Cytheropteron whatleyi, | = Bensonia k. knysnaensis, J = Buntonia rosenfeldi, K = Cytheropteron trinodosum, L = Ambostracon flabellicostata, M = Ruggieria cytheropter- oides, N = Buntonia gibbera, O = Buntonia namaquaensis. ANNALS OF THE SOUTH AFRICAN MUSEUM <= =. 7 é ~ . “ ® N SLO 1 oS we ita t£ Fig. 4. The most abundant ostracod species on the continental shelf off south-western Africa arranged in order of latitudinal centre of distribution (mean of all observed sites, see Figure 6). Vertical bars are degrees of latitude (S); horizontal scales = 100 u. A = Pseudokeijella lepralioides, B = Urocythereis arcana, C = Ambostracon keeleri, D = Krithe capensis, E = Poseidonamicus panopsus, F = Buntonia bremneri, G = Henryhowella melobesioides, H = Doratocythere exilis, | = Paracypris lacrimata, J = Chrysocythere craticula, K = Xestoleberis africana, L = Bairdoppilata simplex, M = Macrocypris cf. M. metuenda, N = Neocytherideis boomeri, O = Austroaurila rugosa. QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 393 Fig. 5. The most abundant ostracod species on the continental shelf off south-western Africa arranged in order of latitudinal centre of distribution (mean of all observed sites, see Figure 6). Vertical bars are degrees of latitude (S); horizontal scales = 100 uw. A = Australoecia fulleri, B = Cytherella dromedaria, C = Neocaudites osseus, D = Xestoleberis hartmanni, E = Buntonia deweti, F = Coquimba birchi. the sensitivity of the species to change in the parameter. In addition, correlation coefficients based on simple regression analyses are presented to show the relationships between the environmental variables (Table 3). To aid reliability, descriptive statistics and correlation coefficients were performed only on samples containing > 100 valves (n = 45). Exceptions to this standard were regional latitudinal and depth distributions, and averages for environmental parameters for the following species, whose ranges into deeper water precluded its use: Krithe capensis, K. spatularis, Buntonia rosenfeldi and Henryhowella melobesioides. PHYSICAL OCEANOGRAPHY Latitudinal and depth distribution Figure 6 shows the total and averaged north—south distribution of the most abun- dant species. Most species (19; 53%) have their northern limits straddling the Walvis Ridge, whereas others occur in the vicinity of Walvis Bay (7), Orange River (7) and the Cape Peninsula (3). In contrast, 33 species (92%) have their southern limits south of the Cape Peninsula. The averaged position for each species is an indication of its centre of distribution (based on the number of observed sites). With the exception of three species, these all lie south of 27°S (Liideritz), and only Bensonia knysnaensis robusta and Palmoconcha walvis- baiensis have their centres of distribution north of 23°S (Walvis Bay). Figures 3—5 illustrate each of the most abundant species, arranged in order of their southward latitudinal distribution. ANNALS OF THE SOUTH AFRICAN MUSEUM 394 00001 90¢6°0- b60t O- ELTEO- eS9lO- S810 0- 906r 0 980 0" GNA) 90$0°0" pny 90¢6'0- 0000' I C7670 88Lt 0 vOTT'O 9Sr0'0 808F O- 6r6t 0 IS6l 07 £80 0- pues anedy ‘one[D eS9I'O- vOIlO 1990°0- STIG O- 0000° | S00C'O™ O6L1'O- ILte 0" cO6t'0- 978P 0" “(O}O10) S8l0'0 = 9060 980¢°0° = 7110 90S0'°0O~ Pn 9Sr0'0 808b' 0° = 6 hot 0 1S61°O" 800" pues 80110" = £9700 OS10°0 6680'0 Ltr 0 aynedy OS6l 0 80et O° = S7S¥'0 9SLE 0 C817 O° = aytuoone|H SO0~'O- = O6L1 0- ILPe'O- = C060" 978h'0 *OoRD 0000' 1 90ce'0° ss LIOE 0 SLLT 0" 16S1 0° 9d 90¢£'0° 0000" I S6LS'0 OOSb'O OSLt 0 DYOW L10¢ 0 S6ZS'0° = 0000"! OC18°O- CEEL 0: uasAxO SLL7O = OOS F'0 OcI8'0° = 0000'I 76060 AMUITeS l6sl'O° = OSL£0 cttL 0 76060 0000' | smesadway, 34 JUOW uaBAxQ ~~ Auryes ‘dway *(SUdWIIDAdS QO] URY) DOW YIIM Sas) SAIqRURA UdIMJaq SAaSA[BUR UOISSI1391 I[CUIIS UO Pase SJUDIDIJJIOI UONR|AWOD € ITaVL QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 395 N A aah é ! 14 Hae nM / | es K ‘\ Ky WAS i \ H fe) t ty ve | 4 20 — WR \ i : ! ” f ae, ae \| | ie | \ Ai hal i V Y | I —WB | ; | {lh fe) | [> northern limit i | 25 | ; ‘ | | in| — LUD i I ae | re , —OR i at i ie mean =e 30° : VL Dal mane | | alan | | —cc p caueEn limit ! | a | — CP ae ~ Pee : Cree ee oe a A Se 2 wy git Bread Cd $ 3 5°S Agen Em Eee Umea Umea Uae ceca Lic elm! pnd neil il wal em ne Vea cancel lal nl ecco acelin S ERT LRMSEGVEBXKTHRHVUAR®THHEDTWHHAHNHA ES HMSHFZHS YARN PSS CRS ES Br CS SSR San Sie aR SESHSSSESSSSETHELTSSS SSS sRZSsEsSsls ss Q2OEEHVDZE SOS Tes FS = is) SSakrctvao 5 a = 9 n pais WS SS Tes seEtTF agave Qk S> od BO ere Ron @ SS 2S Sea aS Se PSoLLouwss Sie: Sea QHEHSE GX SOG So 8 ol oS oe SS eo 4 a Qe & Fe Fecal Pru Ey = QesseMaS€QZsElxc_wsandtoy ¥ &s aes) go-x =Vntr On eos a) = as Cesc S =Suos SsSHeH8FSLVRZ SLSR ~é& SQe ow sac S ay Ss SES SSR SST RESTS SSSI aT SSS cE~ SEES Sass GSHSolC SESE SSSosa SEX Ss Ba Sse H tt assess 3, SQOGS4EOHLSOHLSHSS GH QNlCTeNosP@Eus Segoe SOsqtsSsuFoSgssegne ELLS e®ages e £6 ES Xo TOES Os Rey SSS.) SNS Gas a) Ss PEO) a SR 28 SS Re Bel oS es x = 8 SG Se aa SSS go = 3S 3 = ck Ge ES & $ r 5 Qa Fig. 6. Mean and ranges of the maximum latitudinal distribution of the most abundant species. Vertical scale is degrees of latitude (S). WR = Walvis Ridge, WB = Walvis Bay, LUD = Liideritz, OR = Orange River, CC = Cape Columbine, CP = Cape Peninsula. The mean values are calculated on the number of sample sites; thus they represent weighted centres of distribution and not average positions between northern and southern limits. Figure 7 shows the total and averaged across-shelf distribution of the most abundant species. With the exception of two species (Krithe spatularis and K. capensis), all the most abundant species have their upper depth limits (UDL) shallower than 200 m (i.e. in the inner—mid-shelf area), whereas, with the exception of three species (the least abundant of this category), they all have their LDL deeper than 200 m. The curve of averaged depth distributions has gradient changes separating two shelf faunas (at 250 m, I and II), and upper and mid-slope faunas (350 m, III, and 450 m, IV). Figures 6 and 7 indicate that, with few exceptions (Coquimba birchi, Buntonia deweti, B. gibbera, Bensonia k. robusta and Xestoleberis africana), the most abundant species are relatively cosmopolitan in their distribution along and across the shelf (unlike many of the rarer taxa). Regional variations in the abundances of several of the most abundant species were briefly considered by Dingle (1992), who presented along-shelf variations of the dominant 396 ANNALS OF THE SOUTH AFRICAN MUSEUM I | alt [LL |e Es fe) = =p | ae aN iS rm i * lA, + A | R \ TN HON : A He aed aun wat x YI Y Ae HN | inner — tgs V/ De Pe ONE ee PS mid-shelf - y \ f oe ye Vv “A | /\ eee eo eae ¥ | h Ie, nO ea ies eel T rs \ a Wr /| ‘ " f | | \ | outer shelf, WY MV NA Ee eeeg TM ieamees | | | h | \ | mean \ | \ slope mee SPN \ | \ \ eee pe A E | ye by aT = i} | \/ NE \ ten = 05- ! }* Yeo [toe No s b be | Ml | P | aN \ | | \ | slope ipa a \ | 1 / a | & % e—, | \ as | 4 | | ava || \/ Ve | | ly Ws \| | | | \ | a A $ + oq a aSibisiiziciai or iia Ina nish eb ina ul nw SORTSSSLGSSLLT ELSES SEVERE ES Ge eases se OESEs ) ours QelSy5 SF = 9S o= BG SH 4 > o 3 SSR StS 4h) SED LOM CE ee OP Qa ihey = a= SSS de St Sh SVVSHLSYCBZSSSVCREs ss LESS SSESSHZSESLSSEETS aS) Loe) Sloss o> i c = eo yrs Ho COMSacy asgE = Steg Ss LOW HARDS Ky fats) 2s Ss eo >~oakan Q9H CSG SOOM hes 2589 ea Sen Saueves] Wy ISL ESSss Gases sats Ses cess faces tek faa SX RLS THSNBADYL SSP yes) Ole SS as = : fo ES S SBESSSesSebess SMRISZSESTHSSES SHS seMtSEsees SSS ST, ay ta SS (Sy eS) SY (Sy Ss a ee) BS FS ie ic eeyvs SeSBsESSSLSSss SES Sssgss@esesssagse ~ 20) (6 <5 291g E O54's Sjaynr c= Qasiws ese tsug Se SAE eS Sissy re ap SR es eS i SSG! Ske SO SSS SS aS 5 o> Sieocniee On Oy ss ote e aes cg 6 SO < 2 3 ov Ss el SS tsi se Go x o = SiOp obs oats gs § a adh Lacks Ss = Q oO ec Q S 5 SG uate Ss = Fig. 7. Mean and ranges of maximum and minimum depth distribution of the most abundant species and barren sites. UDL = upper depth limit, LDL = lower depth limit. The mean values are calculated on the number of sample sites; thus they represent weighted centres of distribution and not average positions between upper and lower limits. I-IV on the upper border demarcate species grouped between gradient changes in the curve of mean values. taxa within various latitudinal sectors. A more comprehensive analysis has been carried out, and is summarized in Figures 8 and 9. These represent projections of abundance values (as smoothed percentages of the total fauna) on to across-shelf (depth), and along- shelf (latitudinal) axes, respectively. A plan of the distribution of dominant taxa (> 20% total fauna) on the shelf and slope (Fig. 10) was constructed using Figures 8 and 9, and additional depth/abundance profiles computed at intervals of 5° latitude. A simple calcu- lation of regional dominance gives the following abundances in order of rank: areas north of 24°S— Palmoconcha walvisbaiensis = 32 per cent, Cytherella namibensis = 21 per cent; south of 24°S — Pseudokeijella lepralioides = 36 per cent, Ruggieria cytheropter- oides = 22 per cent, Bensonia knysnaensis knysnaensis = 6 per cent; in water > 500 m — Henryhowella melobesioides = 43 per cent. The inner—outer-shelf region (0—300m) is dominated by three species (Fig. 10). North of 23°S, Palmoconcha walvisbaiensis occurs on its own but, south of 25°S, is replaced, respectively, by Bensonia k. knysnaensis on the inner shelf and Pseudokeijella , QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 397 80 inner — outer shelf — mid —- upper slope mid-shelf uppermost Per cent " Gh LAL \N A LE NNA WSS 70 iN NS a Ah , —— Depth (km) Palmoconcha walvisbaiensis Cytherella namibensis Bensonia k. knysnaensis Pseudokeijella lepralioides Ruggieria cytheropteroides Henryhowella melobesioides Fig. 8. Variation of species dominance with depth across the continental margin. Constructed by projecting all data points on to a single axis, and smoothing each curve with a five-point running mean. lepralioides on the mid—outer shelf. Immediately south of Walvis Bay, there is a mixed assemblage containing Palmoconcha walvisbaiensis and Bensonia k. knysnaensis. A further mixed zone occurs between c. 31.5° and 34°S, where the two dominant taxa are ‘diluted’ by the relatively diverse and abundant faunas off the south-western Cape (which contain many of the rarer taxa described by Dingle 1993). Outer-shelf and uppermost-slope areas are dominated by two species: Cytherella namibensis in the north and Ruggieria cytheropteroides in the south. Upper and mid-slope areas are dominated by Henryhowella melobesioides, with a narrow mixed zone contain- ing abundant Krithe (mainly K. capensis) and the deeper-water species of Buntonia (B. rosenfeldi, B.bremneri and B.namaquaensis) intervening between the Cytherella namibensis— Ruggieria cytheropteroides upper-slope assemblage and the Henryhowella melobesioides upper—mid-slope assemblage. All three inner—outer-shelf dominant species typically constitute 40—50 per cent of the local populations; projecting their abundances on to a cross-shelf axis (Fig. 8) empha- sizes that each taxon reaches its individual maximum at different depths: Bensonia k. knysnaensis, 50 m; Palmoconcha walvisbaiensis, 80-110 m; and Pseudokeijella lepralioides, 398 ANNALS OF THE SOUTH AFRICAN MUSEUM y Central Namib “lassociation SW Cape association Per cent Yt Ln Palmoconcha walvisbaiensis Cytherella namibensis Bensonia k. knysnaensis Pseudokeijella lepralioides Ruggieria cytheropteroides Fig. 9. Variation of species dominance, expressed as a percentage of total ostracod population, with latitude. Constructed by projecting all data points on to a single axis, and smoothing each curve with a five-point running mean. WR = Walvis Ridge, WB = Walvis Bay, LUD = Liideritz, OR = Orange River, CC = Cape Columbine, CP = Cape Peninsula. 130—180 m. In contrast, a similar degree of dominance on the outer-shelf and uppermost slope is only reached south of 25°S (Ruggieria cytheropteroides), whereas north of Walvis Bay, Cytherella namibensis constitutes only 20—30 per cent, with other taxa being rela- tively more important. Below a transitional zone (450—550m), Henryhowella melo- besioides progressively increases its dominance, reaching > 70 per cent in water deeper than 900 m. Its eventual maximum (> 80%) occurs at 1 200 m on the middle slope, before rapidly declining below 1 500m (Dingle et a/. 1989, 1990; Dingle & Lord 1990). Finally, summaries of regional simple population diversity (expressed as number of species/sample) show a preponderance of inner—mid-shelf species south of the Orange River (Figs 11, 12). Latitudinally, there is a progressive increase in population diversity from < 10 species north of the Walvis Ridge to > 50 species off the south-western Cape (Fig. 11). The increase in numbers is particularly high across the Walvis Ridge and in the vicinity of Walvis Bay, whereas between the latter and the Orange River, there is a plateau (33 species). A maximum is reached off the southern Namaqualand coast (45 species), south of which the diversity decreases slightly, reaching a low at 33°S (Cape QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 399 Central Namib SW Cape Association Association ORANGE R. LUDERITZ | C. COLUMBINE 25° 30 WALVIS C. PENINSULA WALVIS RIDGE BAY : (e} 5 20° = ie} = fe 1 0 <— = >) (= 35 i oo E = 0.55 Krithe & So Buntonia aca o ° 2 © > |) sna See ee 3 Qa Qa S ! x3 E Palmoconcha walvisbaiensis Cytherella namibensis Bensonia k. knysnaensis Pseudokeijella lepralioides Fig. 10. Latitude—depth plan of areas dominated by various species (> 20%). Constructed using profiles similar to Figure 8 at 5° intervals of latitude. Columbine: 40 species), before rising very rapidly in the vicinity of the Cape Peninsula (55 species). Across the shelf, maximum diversity (40 species) occurs between 160m and 200m (Fig. 12). There is a rapid increase from the inner shelf, with a subsidiary maximum (33 species) at 100 m, and an equally rapid decline into water between 200 m and 300 m. A diversity plateau (24 species) extends to 500 m, below which there are two further declines in species numbers (530m and 710m) to 10 species between 800 m and 900 m. Temperature and salinity The correlation coefficient between temperature and salinity is high (R = 0.8960; Fig. 13A) at all 270 continental-shelf sites, so that these two parameters vary sympath- etically. The correlation between temperature and dissolved oxygen in the bottom waters is lower (R = —0.7432; Fig. 13B), whereas with other parameters (e.g. CaCO3 and organic matter MORG) it is < 0.5000 (see Table 3). The distribution of temperature and salinity preferences has three well-defined categories (Figs 14, 15). Two species prefer high temperature and high salinity (> 11°C, > 34.90%.) — Palmoconcha walvisbaiensis and Bensonia k. robusta — and, in both cases, their means are markedly different from those of other species. 400 ANNALS OF THE SOUTH AFRICAN MUSEUM CC s ° i LUD i at 5 o WB 7 ‘ee ) wf | 5 ’ ef teem rn o oi = a 3 W. Ridge eal i o "8 o i 0) Irae eal T T I ina alge N 20 25 30 Ss Fig. 11. Variation of simple species diversity of total fauna with latitude. The complete latitudinal range of each species has been used and the assumption is that the species occurs at all sample sites between these limits. The curve is a five-point running mean through the sample sites plotted on to a single N—S axis. Horizontal axis is in degrees of latitude. W. Ridge = Walvis Ridge, WB = Walvis Bay, LUD = Liideritz, OR = Orange River, CC = Cape Columbine, CP = Cape Peninsula. T T T T T T T T ! mid — upper slope Number of species outer shelf mid-shelf uppermost slope T 0.5 Depth (km) Fig. 12. Variation of simple species diversity of total fauna with depth. The complete depth range of each species has been used and the assumption is that the species occurs at all sample sites between these limits. The curve is a five-point running mean through the sample sites plotted on to a single E—W axis. 401 QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA SUS Me fe Bo ’ go Meee t, | wo two 270). B. Temperature against dissolved oxygen one standard deviation, outer dashed lines | suejmjeds ayy i sisuadeo aylly 100 specimens. 402 ANNALS OF THE SOUTH AFRICAN MUSEUM 35 ee ml mean salinity V CS & 348+4+4h VA I | ise) ” =) co) fs hi oF seth Ke | {tee IL NE | ao 46 Teal ben ® jo ae E 34.475 eel eee mn Oo. | Ree 02 I D salin | LAC | | | | ele Zaa\i| | | 1h | es | | eal el | 0 5 tt tt 44 A~AEMNANAHR ATH |G BVH HS DH AOADADPADAEDHTxKoEVP HME YDS 4 BSR Ree E SS EES SSS TS eS see eS eS LSS PST essay Seep Ss SieOmss Bl gases x< RES) =qQ &’S ere CH SGASSOSCFSS PSs C HAQ4HH SSG Z< e—easgenvsSsxesEes Sc -S5 8 = 8 es Sf eS Sie Skcrciee > eS STESCHRESCL SH Ror So fH Cc is} a — ~ 6oaqa~FRe SG — ~ ot OUD SOMO SSS) 5 SOs © & TS VX 3 xX~SBOgatL SRE sd 4 @ -2 ov S SSSSS ee SSS sssssscsscse sas ss c= acces mw SOPs SeaseSsess ese sSSESESSES Sas SHEXS S SssSPes SFeeSssse S=FFSszsa 8 oss ~ 8 < & 7) © gsess&s ssstsegs 2 sex 5. 2 Sea S iS 9X4 SBHUSE x< re 39 rosy aL Ss 3 SOURS ts a Sy ee ENS < 35 2 =x 2 te a S358° a se & EL oe & 5 8 a xt Ss = Fig. 15. Mean and standard deviation (SD) of sea-floor salinity for species at each site containing > 100 specimens. At low temperatures/salinities, three species have means below 7°C and 34.6%bo: Krithe spatularis, K. capensis and Buntonia rosenfeldi, with Henryhowella melobesioides closely associated with this group. The remainder of the most abundant species fall within the following ranges of mean temperatures and salinities: 10.17—8.73°C, and 34.89—34.70%o, respectively. Correlation coefficients between the various species, and temperature and salinity are shown in Table 2. Palmoconcha walvisbaiensis correlates most positively with temperature and Buntonia gibbera with salinity, whereas Ambostracon flabellicostata correlates strongly with both. Four species correlate negatively, with Buntonia namaquaensis returning the largest values for both parameters. Abundance and species diversity trends of the whole ostracod population (i.e. most abundant species plus rarer species in all samples) with temperature and salinity are shown in Figure 16. QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 403 A 600 TEMPERATURE > 3 : > 400- ra feb) oO = cs ne} (= =) 2 < 200- o- SALINITY sf 3 : s Qa @® oO = co 72) = =) © < 34.4 34.6 34.8 35.0 35.2 35.4 %o Fig. 16. Relationship of diversity (top panel, light curve: number of species) and abundance (bottom panel, dark curve: number of valves/100 g sediment) for whole ostracod assemblage. A. Sea-floor temperature. B. Sea-floor salinity. Maxima in both abundance and diversity lie within the temperature range 7°—10°C and salinity range 34.6%0—34.9%o. There are further minor peaks in the high temperature/ high salinity areas of the graphs, although these are not in phase, implying that at the higher values, one or other of the factors is dominant in determining the distribution patterns. Dissolved oxygen The distribution of species’ means for sea-bottom dissolved oxygen is skewed towards a preference for high values (Fig. 17), although it must be remembered that, 404 ANNALS OF THE SOUTH AFRICAN MUSEUM 4 etteetertettt deat LLL aE Sitbhdde Hihniiacaes@QUH ELL We m/l ne) — (o) 4 BARDOT NMS AXES ETUONABMVHOVLCWCHVAXHEHSAANHArNFZLYS HEY SS SRST SR ES STS SSS SS s esses eysasessesee ES Ow 4235 QEGFCQCsaesogssxprsg RS) = SSSSFBSZFICSCSEREKGSS GRE sc oegge sos ggHgdgcg ~gasgs SSeS o 9 & Se Qa SCe ss ggssseaguaasa eget Seo er gl SO 2a © Sia S45 S18 Sa Oo Soe teceNpORseecEG SSF®a "FoF GESGHRASHSSEG OT Bets 4 > SS Go Gl Sion SSeS Cy ae ee SF SSgwHstcecRaeaSsesxsagss LC. 3 = 2 < Ea y,re®PeEvorserotocal ds Cees > x SSE SsSHSO>G4Y¥y SEES EOQRSCsspFrsr~sFsass aé& 2 SE®stSntseseasssssesgEes SFVe FL wa eSSsNAe oes Bo x E See = SOS) Seo SiS a S78 fe oo ats SY SE THEO CLT c 2'E = = = or Sao eS SO ® ror 5 4 3x is} c LHsHS SSeS eos esse sa“ SSSSSLSES SA a SS$su v8 ay ~ — Gy, Ia cr, as oO [s) HimQagxeers oO (d= < of SfIsF FS Ha Q= 2a SeesssSsSs 5 ceca Sra) Sig AO PS Xm SF FRD 2 ~) 26 iS S <> 2 ro) x ote ed = s2) 5 =} iS) =8 = rm) ) BeOS § Q = g S S 5S a ras) es S = ts <7 a Fig. 17. Mean and standard deviation (SD) of sea-floor dissolved oxygen for species at each site containing > 100 specimens. according to the terminology of Chapman & Shannon (1985), the whole of the west-coast continental shelf falls within the category ‘oxygen-depleted’ (< 5 ml/l). Correlation coefficients between dissolved oxygen and other water parameters are greatest between salinity (—0.8130) and temperature (— 0.7332), whereas between oxygen and sediment parameters, the closest links are with organic matter (— 0.5795), glauconite (0.4525) and CaCO; (—0.3471) (Table 3). There are four gradient changes in the mean oxygen curve (Fig. 17), isolating five unequally-sized groups of species. These occur at 3.4, 3.1, 2.8 and < 2.5 ml/l, with the bulk (21; 58%) plotting above > 3.4 ml/l, where Krithe spatularis, Henryhowella melobes- ioides and Macrocypris cf. M. metuenda occupy the top three rankings. Only two species have a preference for oxygen-deficient water (< 2 ml/l): Palmoconcha walvisbaiensis and Bensonia k. robusta. Their mean values (< 1 ml/l) are markedly lower than the next lowest groups, in which only two fall below 3.0 ml/l (Buntonia namaquaensis and QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 405 800 | OXYGEN 600 5 Diversity Abundance ORGANIC MATTER Diversity 200 Abundance 0 5 10 15 20 Per cent Fig. 18. Relationship of diversity (top panel, light curve: number of species) and abundance (bottom panel, dark curve: number of valves/100 g sediment) for whole ostracod assemblage. A. Sea-floor dissolved oxygen. B. Organic matter in sea-floor sediments. Neocaudites lordi). Cytherella namibensis, Bensonia k. knysnaensis and Buntonia rogersi constitute a further group clearly able to tolerate a degree of oxygen depletion. Correlation coefficients between species and dissolved oxygen are listed in Table 2. Two taxa strongly correlate with fluctuations in this parameter: Cytherella namibensis (negatively) and Buntonia namaquaensis (positively). A further three species (Palmo- concha walvishaiensis, Bensonia k. knysnaensis and Neocaudites lordi) also correlate nega- tively with dissolved oxygen values. 406 ANNALS OF THE SOUTH AFRICAN MUSEUM Abundance and species diversity trends of the whole ostracod fauna (in all samples), with dissolved oxygen values, are shown in Figure 18A. These are similar to those displayed for the most abundant species data, and have a distinctly trimodal distribution, with maxima at 0.6 ml/l, 2.2—2.5 ml/l and the main maximum between 3.0—4.2 ml/l. BOTTOM SEDIMENTS AND GEOCHEMISTRY Correlations between the physical oceanographical and sedimentary parameters are shown in Table 3 (based on samples with > 100 specimens). The only relatively strong correlations are the negative relationships between temperature/salinity and calcium carbonate, and between oxygen and organic matter. Within the sediments, the only relatively high correlations are between mud and sand, and organic matter. I have investigated the correlations between the overall ostracod abundance (number of valves/100 g sample), simple diversity (number of species/sample), and various par- ameters using both the whole data set (including and excluding barren sites), and only those samples with > 100 specimens (Table 4). In both cases, only the dissolved oxygen values showed relatively strong positive correlations, with the diversity having greater dependence than the abundance (to a maximum of 0.5575). Mud content showed the second-strongest correlation (to a maximum correlation of 0.3839). Correlations with both temperature and MORG are weak. TABLE 4 Correlation coefficients (based on simple regression analyses) between environmental parameters and ostracod populations. Temp. Oxygen Mud MORG WHOLE DATA SET, INCLUDING BARREN SITES Abundance -0.056 0.239 -0.129 -0.105 Simple diversity -0.197 0.489 -0.283 -0.268 WHOLE DATA SET, EXCLUDING BARREN SITES Abundance 0.011 0.187 -0.080 -0.074 Simple diversity -0.165° 0.458° -0.281° -0.306° SITES WITH > 100 SPECIMENS Abundance -0.1642 0.2167 0.3839 0.1075 Simple diversity -0.2189 0.5575 0.2945 -0.0493 © = exponential model CaCO, reflects the biogenic component Fe reflects the terrigenous component MORG = organic matter Abundance = number valves/100 g sample Simple diversity = number species/100 g sample Organic matter (MORG) The distribution of mean values of organic matter in the bottom sediments plotted against species distribution is shown in Figure 19. Most species (23; 64%) have a preference for organic matter values within the range 2.7—3.9 per cent. Only one species QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 407 Per cent \ |] | | SD MORG } | | | /| | ea | | | | | » | | : 14 1 41] | CTY T V7 | ( siceat Saale ese — rm CBSE SERBZDBDOWVLHAAGACTHHKE DA QBAHADMWHAHS TS HBowYW4OH HD x SSS TO See eT ee SSK ES SGT IQS sTggrgg_ssass SS Se SSS Ee RES BESSSSSLSESSESSECESS SSSES ES SSSR SS sels sso gees ssssree ss esse = = = ise) ~Fok Dn oa .G Q Qgatd eQqgok HORYAOTQM cs ano) 6s 3 SS EQ % ~ : ~ Saas Qeq QeeQ TBAQ % ASS TS SS Sy a a) RS SES IG) (OS SID Co GS oS es = i) 2 ~ Qe erstrds~_.4 XL ofa Ff THR SSLEPSSLT SESS SSS TS SEF ees FS sees Ss ssa 3 9 SOogo068tUCUS KX 2) 35o 8 SSS SHesesE 100 specimens. (Austroaurila rugosa) has a low tolerance of organic matter (< 2.0%), whereas five others have mean values < 3 per cent (Neocytherideis boomeri, Bairdoppilata simplex, Poseidon- amicus panopsus, Palmoconcha walvisbaiensis and Buntonia gibbera). The inclusion of Palmoconcha walvisbaiensis in this group may be anomalous, as the mean for this species — based on all sample sites ——is 5.78 per cent. The species most tolerant of MORG (> 5.0%) are Coquimba birchi, Buntonia deweti and Xestoleberis hartmanni. Although, in general, the correlation between oxygen and organic matter in the sediments of the west coast is only moderately strong (R = —0.5795; Tables 3 and 4), the relation- ship is borne out by the mean preferences of Austroaurila rugosa and Neocytherideis boomeri (low MORG), and Bensonia knysnaensis robusta, Neocaudites lordi and Buntonia rogersi (high MORG). Correlation coefficients between species and organic matter in bottom sediments are listed in Table 2. Two species correlate negatively with organic matter: Macrocypris cf. 408 ANNALS OF THE SOUTH AFRICAN MUSEUM M.metuenda and Henryhowella melobesioides, whereas 12 species correlate positively, with Cytheropteron trinodosum showing the highest value (0.8102). Abundance and species diversity trends of the whole ostracod fauna with organic matter are shown in Figure 18B. Although the curves are relatively complex, they are essentially bimodal: maximum abundances and diversity occur between one and 4.5 per cent organic matter in the sediments. These values are similar to those for the majority of the most abundant species (Fig. 19). In terms of species diversity, the maximum MORG values lie at the lower end of this range (c. 1.5%), whereas maximum population abundance occurs at somewhat higher values (3.0—3.5%). The effective cut-off maximum values for significant population abundance and species diversity are 7.0 and 7.5 per cent, respectively. Terrigenous sediments Variations in the elemental Fe content can be used to characterize the terrigenous component in marine sediments on the continental shelf off south-western Africa (e.g. ee ee |e ea |r| al eC | a || Sa mean Fe (= terrigenous) | SSeS Sse es Per cent (ae) if | } | t } 4 | | T N | eae ee La ab + + - 1 Hee | | eal | | Her Pi ieile | | | (met [ee es tna Oaeclepetigee! T- LLL a Lm Ue SUI aL Lea ed Daa ea tT 5 >< SESHSEGRSSSESLES SEL SESSSELLSS SE Seeese a SSSSSICRSSLSESS SHES SS GESS lS SEssszeseess S “aS Gs. BS SSHSGALSFS CO Sp 208 G2 OO 2 SoS SESSSESTSSSSSHTLESEES SSS ese ase Ses eee SSoSeBHSasP RSF sys segs Sesces tester age RESO CSises SSS Pate oo o242R Gx s ox STRKAX D = » 2D Ss Q.6 255 = & eS SS SSS oa iS Se SSESSESSSECSTHSSESLHARSE SSP SESCESLSVASS cg O20 + 5 SST Sse © SS DRS = = oS = 0 5 2 Se = Seer oO o c ~ Oo) 2 S o MS = od Sees Cc SS UBMBERSTSSSESSSESSSS SS Ses sols owes eos oat CQyHyOCTELxHEVS x SsSGZGaee SS 3 West (Sion “Sos & Seoefs a Ley Rew Sw Ss Ss x Sia “5 as NM SX mo aS) = se asees 3 Sfiac S > =< £50055 S OR 4 S 3 9 = Océ a 5 ek S os Q = = Fig. 20. Mean and standard deviation (SD) of Fe (= terrigenous component) in sea-floor sediments for species at each site containing > 100 specimens. QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 409 Bremner & Willis 1993). Figure 20 shows the mean values associated with the most abundant ostracod species. Three species lie at the upper end of the Fe (> 5%) curve: Coquimba birchi, Xestoleberis hartmanni and Neocaudites osseus. At the opposite end of the graph, the species associated with values of Fe < 2 per cent (i.e. terrigenous-poor environments) are Buntonia gibbera, Krithe spatularis and Buntonia rosenfeldi. Correlation coefficients for Fe (Table 2) are strong only for Buntonia namaquaensis and Buntonia rogersi (negative), and Xestoleberis africana and Australoecia fulleri (positive). Biogenic sediments Variations in average values of CaCO3 are used to express the biogenic component in bottom sediments (Fig. 21). 90 ] can ea al lien nal ] 79 PPE Seen asta | th ae Pel aly 2] Pa Reali ite pelestetin \ | | 70- : Ea Se 60> oe ' ia LL, © . ba eal | fe) mean terrigenous (Fe) || | | | | | | lt il] | O Ts ea et SEN e st peal wo 20> ale ieee lteaanl 5 ne O | 4a ~ € c 40 5 4 0 seb) iS) ) c te | a ® @ 307 7 34a a | L } bg | ; | | m carbonate 10- Ria Z 1 \ \ elena led Hees | tt \ Qo0—__——— — = r@) 2) 2) nro SOHKTOHAHHTEVHOEKXBVHVHYHYYOHDSZREEES SSR eee SASS SS CERES SESS SRSAR2AGESSSEES Q2ESFCS EH QV Qs = ose%og Qre ny oad Pir SSR RT CS SREESSSS SST LEL EES SSS SS Ry SSsEs S25 ess GglasrgCoMe yt grVVoeE ices Fo ama i da) oe i ee eS Sie ee Soe NOES oon Cl is ee Oa eS pene ZRClix~awaeecert Wc gn FY oS? o o4%2,8 3569 9 Sos eee SS ge aos CQeuwlg TS SRERRCERLSCHKSLsStssacgse SSTLST TT Fc SSeS RSET SSFP SGs Ra Sis se See sey c = >= 2 = SeseS PLES SSRs SSls ss sss seas sa ge saacs =£ce¢E LSter Ogg Stat = ow’ 3 is) Sf £9 CES: <> % a2) ra aS) £& Oe < Singers sss Qo cee ee Se lao sik oe % S cD Boxes sS a) Q x QNEOGQ iz 6) x So SS Se es SL > SS HS oS gs a ASS) ES se re = EO ES Q Ss SC re Fig. 21. Mean and standard deviation (SD) of CaCO; in sea-floor sediments for species at each site containing > 100 specimens. This factor is a good indicator of the biogenic component of bottom sediments. To illustrate the antipathetic relationship between biogenic and terrigenous components, the mean per cent of Fe is also plotted. 410 ANNALS OF THE SOUTH AFRICAN MUSEUM Twenty-six (72%) of the most abundant species occur in sediments with average calcium carbonate values > 50 per cent. Seven species occur in sediments with average values > 70 per cent, with Buntonia gibbera having a mean value > 85 per cent. Palmo- concha walvisbaiensis is the only species to occur in opal-rich sediments (mean value of 28% for all sample sites). The three species having the lowest affinity for carbonate-rich sediments (< 45%: Xestoleberis hartmanni, Buntonia deweti and Coquimba birchi) all have a high affinity for terrigenous material. This expresses the general relationship between CaCO; and terrigenous means (Fig. 21), which shows that, as the former decreases, the mean for Fe increases. A simple regression analysis between the values on this curve gives a correlation coefficient of —0.6264. Correlation coefficients for CaCO3 and various species are listed in Table 2, where the strongest relationships are between Austroaurila rugosa (positive) and Cytheropteron trinodosum (negative). _| mean authigenic Per cent a | (0) ere cago ee a eae Sd ae aa so, mo) a) Te ty eS pos om eS PR. OS See eT eee SST SSSR STS ES ESSESRSSSERSE SS GS % ty Pees TS Scie SS aS cD aS) $ ox SOD GS ry SUS SS SeSsET OS oo o 2 6 } oa PRES wee SS SESS PSST SESRESESES SESS GS, less ‘oa “ go 0 TS) th aa) Bw = 2 4 oF mw Qo so S P&S ee ses sse estes seen e sees eee Ok eS CS ROS TS a SS a ee) A) RS as) SS Ls 4 = o v of > oS x= co 3b 2 a & 8S B=S RESSSESSSSESSES LESH Ss 2S S Sos Seceseeecee Bee SSESSSSESPSSe cess S28 Pee Sa Cpe 353.0 6 SBNGHEHOTHESGETRSBAVSosSSseQ se $ Sse SS iS QO Soa: S Iausx ~ SO gaaacy Sto. x ~ a od SP Gs) Shee 205 Gi SeS ioee sus Ser cronmnomoms 7 8 go a ASS a RS) SS S ak a ® x & iS) Ss 2 2) 6) gaGos 5 G92 = iS) % > a Q S ) S ) x 1S) S S Q ce S r) g SE Q Fig. 22. Mean of authigenic minerals (phosphorite and glauconite) in sea-floor sediments for species at each site containing > 100 specimens. QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 41] Authigenic sediments Authigenic minerals are relatively abundant on the continental margin off south- western Africa (e.g. Birch ef a/. 1986; Bremner ef al. 1986). To express the relationship between species distribution and authigenic bottom sediments, the combined average values of apatite (in the form of phosphorite) and glauconite have been plotted (Fig. 22). Note that data for Krithe spatularis, K. capensis and Henryhowella melobesioides have been omitted (too few samples contained authigenic minerals for reliable means). The distribution falls into two clear groups: species with means > 4 per cent and those with < 3 per cent. In the higher category, Australoecia fulleri (9%) occurs apart from the other means, which lie approximately linearly between 7 and 4.5 per cent. Other species favouring authigenic-rich sediments are: Macrocypris cf. M. metuenda, Cytherella dromedaria and Bairdoppilata simplex. At the lower end of the curve, 11 species lie within a narrow preference band of 2.2—1.8 per cent. Plotting phosphorite values separately (lower curve in Fig. 22) shows them to lie along an approximately sympathetic curve, with glauconite forming a somewhat greater proportion of the total at the higher value end of the curve. Coefficient analyses for apatite and glauconite show that several species have strong correlations with both minerals: Buntonia namaquaensis, Urocythereis arcana and Austra- loecia fulleri (positive), and Bensonia knysnaensis knysnaensis and Neocaudites lordi (negative). Of these, only Australoecia fulleri and Neocaudites lordi prefer sediments with high and low mean values of authigenic minerals, respectively. Sediment texture Affinities for bottom-sediment types have been expressed in average values of sand (> 63 w) and mud (< 63 y: silt + clay) (Fig. 23). In the mud-rich sediments (> 30% mud), there is strong representation by deeper-water taxa, with four of the first six species in ranking having average depth occurrences > 400m (Krithe spatularis, K. capensis, Buntonia rosenfeldi and Henryhowella melobesioides: Fig.7). The remaining two, Coquimba birchi and Buntonia deweti, are mid—inner-shelf taxa. Most species (92%) occur in sediments with average mud values > 20 per cent, and only three are strongly displaced off the curve at the mud-poor end of the graph: Austroaurila rugosa and Bensonia k. robusta. The plot of average sand values is almost complimentary (the differences representing relatively small gravel components) and all species lie between approxi- mately 60 and 90 per cent sand. The two main exceptions are Palmoconcha walvisbaiensis and Buntonia namaquaensis. Both values have high standard deviations and probably result from variance in the data set. Correlation coefficients for sand and mud (Table 2) indicate that Austroaurila rugosa is the most sensitive indicator of changes in the ratio of the textural parameters (positive for mud, negative for sand). POPULATION STRUCTURE Brouwers (1988) and Whatley (1988) have both recently discussed the question of the structure of ostracod populations in assessing environments. Most podocopid ostracods moult eight times to reach maturity (Brouwers 1988), so that complete preservation of an 412 ANNALS OF THE SOUTH AFRICAN MUSEUM 100 Per cent Sais eS Se ee ee af | barren Krithe capensis Coquimba birchi Buntonia deweti Krithe spatularis Henryhowella melobesioides Buntonia rogersi.. ——$_—_$_—— oo Neocaudites osseus |——_|—___ Urocythereis arcana Buntonia gibbera Neocytherideis boomeri Neocaudites /ordi Australoecia fulleri Palmoconcha walvisbaiensis Buntonia bremneri Cytheropteron trinodosum Ambostracon flabellicostata |__| Buntonia rosenfeldi Macrocypris cf. M. metuenda Paracypris lacrimata Bensonia k. knysnaensis Xestoleberis africana 4 ——_+—— Doratocythere exilis Xestolebris hartmanni Ambostracon kee/er;_..——_—— SS Sa Cytherella dromedaria Incongruellina venusta |__| -_| — Pseudokeijella lepralioides | |__|} Ruggieria cytheropteroides 4~_|____|— Buntonia namaquaensis Poseidonamicus panopsus Cytheropteron whatleyi Bairdoppilata simplex Cytherella namibensis Austroaurila rugosa Bensonia k. robusta Fig. 23. Mean mud and sand content of sea-floor sediments for species at each site containing > 100 specimens. ostracod population would give a juvenile: adult valve ratio of 8:1. Theoretically, any post-mortem partitioning by bottom currents will disturb this ratio, so that values < 8:1 will indicate populations from which early instars have been winnowed, and values > 8:1 environments into which currents have carried fine suspensate, including early instars. Brouwers (1988) considers that the ideal 8:1 ratio is unlikely to be achieved in most natural environments, where the smallest instars are destroyed through predation, dissolution and crushing, and in her work she concluded that the ‘ideal’ ratio is likely to bel Gira or 5 le Figure 24 is a histogram of the juvenile: adult ratio of the samples with > 100 ostracod valves and was constructed following the same technique employed by Brouwers (1988). Fifteen per cent of the sites have a ratio 7:1, and one site has the theoretically ‘ideal’ ratio 8: 1. In addition, 44 per cent of the sites have a ratio between 6 and 5:1. Consequently, at 59 per cent of the sample sites, sedimentation has occurred under relatively low energy conditions (according to criteria used by Whatley 1983 and QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 413 105 z | j 9- B | 7,7 = ey ea ill a Ti | Til mo ALLL 7777 ; mii 7 Tiiiill FORO oo 1 AS 5) 6 "4011.12 13 14 ba | -+ © i 100 specimens. Brouwers 1988). In contrast, 39 per cent of the sites have juvenile: adult ratios that indicate some post-mortem disturbance, and the majority of these (29% of the total) suggest removal of instars, presumably by currents. The problem with this type of approach is that the instars of larger species are larger than adults of some smaller taxa, and that methods relying on the juvenile : adult ratio or a detailed population age structure, using all the various instar stages (e.g. Whatley 1988), take no account of size differences between species. Nevertheless, the results have been presented for comparative purposes, and possible implications for sea-floor conditions will be mentioned further in the discussion section. BARREN SAMPLES In understanding the distribution of the ostracod assemblages, a knowledge of the environments in which they are not found is almost as important as knowing the circumstances under which they do occur. Of the 270 samples examined for ostracods, a surprisingly large number (81; 30.0%) were barren. These sites extend from west of the Cape Peninsula to just south of the Kunene River (Fig. 25) but are concentrated in two main inner—mid-shelf areas: north and south of the Orange River, and in deep water. In detail (Fig. 26), both shelf areas are further subdivided: a small cluster of sites occurs west of the Cape Peninsula between 200m and 300m, separated from the Namaqualand inner-shelf zone, whereas the extensive northern zone, which becomes progressively deeper south of Walvis Bay, is 414 ANNALS OF THE SOUTH AFRICAN MUSEUM 15° 20°E y PAC 3A 20° Ne +N Ne 4 ‘| 3B a ee Al ++ + WALVIS BAY 1 \ +HH a tk em a A 25° 4 ma + : i ? LUDERITZ =| +. . 300 + 4 (— ™ Cape Columbine (moO at Stgicere POUR ns i Ree —— sa ee coal 7 gt Fig. 25. Distribution of sites barren of ostracods (black squares) in relation to ostracod- bearing sediments (crosses). Areas numbered 1—5 are also shown in Figure 26, and described in the text. separated from a small number of barren sites in deeper water on the Walvis Ridge Abutment shelf. I have numbered these areas 1—5 on Figures 25 and 26. The extensive barren zone on the upper slope lies in progressively deeper water from north to south (550—1 000 m). Within the barren areas, the ratio of barren to ostracod-bearing sites is high, reaching 2.8: 1 off Namaqualand (mean of 1.8: 1; Table 5). In relation to the regional distribution of ostracod valves, there are frequent rapid transitions from barren areas to regions of relatively high abundance (> 20 valves/ sample — Fig. 26). In particular, this occurs along the western edge of the Walvis Bay— QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 415 TABLE 5 Statistics of barren and ostracod-bearing samples. Barren Ostracod-bearing Rati Area* sites sites ae (B) (O) i | 7 9 0.7 2 7 3} 2S 3 49 20 ZED 4 11 4 2.8 5 8 0.9 Total 81 44 1.8 *—areas indicated on Figure 25 Walvis Ridge sector (area 3), immediately west of the Orange River (area4), and immediately south and inshore of the Cape Peninsula (area 5). Environmental parameters of the barren sites Mean values of various parameters within the areas 1—5, into which the barren samples are concentrated (Fig. 26), as well as overall means for all barren sites, are shown in Table 6. In comparison with the mean values for the various ostracod species, the means for all barren samples show the following features: 1. High temperature (10.8°C) and high salinity (35.0%). Only Palmoconcha walvis- baiensis and Bensonia knysnaensis robusta are higher (Figs 14, 15). 2. Low dissolved oxygen (1.5 ml/l). Only Palmoconcha walvisbaiensis and Bensonia k. robusta are lower (Fig. 17). 3. High organic matter (6.6%). This value is higher than the average for any individual ostracod species (Fig. 19). 4. High mud content (47.3%). This value is 5 per cent higher than for any individual ostracod species (Fig. 23). 5. Low carbonate content (15.7%). This value is 10 per cent less than the lowest for any individual ostracod species, and less than half the mean for the rest of the most abundant species (Fig. 21). 6. Moderate average Fe values (nominally representing the terrigenous component of the sediments) (Fig. 20). 7. Moderate to high average authigenic mineral content (Fig. 22). When the mean values of parameters in barren areas 1—5 are considered, however, it is clear that no single factor is responsible for the absence of ostracods from regions of the west-coast margin. Nevertheless, there are several factors in common between some of the areas. Area 1. Upper—mid-slope (mean water depth 763 m). Characterized by low tempera- ture, low salinity, relatively high organic matter and carbonate contents. 416 ANNALS OF THE SOUTH AFRICAN MUSEUM Depth (km) 1.0 Slope 0.5 Shelfbreak Shelf (6) : N 20° — WR — WB 25° — LUD — OR 30° — CC — CP 35°S Ss >20 ial >500 [aa] barren areas Fig. 26. Latitude—depth plan showing barren sites (black squares: areas 1—5 with thick outlines) and ostracod abundance (crosses: specimens/100g sample). Vertical scale is degrees of latitude. WR = Walvis Ridge, WB = Walvis Bay, LUD = Liideritz, OR = Orange River, CC = Cape Columbine, CP = Cape Peninsula. TABLE 6 Mean environmental parameters for barren areas. Baeamaie? Barren areas* All | 5) 3 4 5 samples Depth (in) 763 287 94 107 218 182 Temperature (°C) 4.5 Piel 12-2 9.7 8.9 10.8 Salinity (%c) 34.47 35 35 ez 34.8 34.6 35 Dissolved oxygen (ml/I) 2.8 l 0.8 22 3.8 IES) Organic matter (%) 6.5 6.9 7.6 4.2 0.98 6.6 Mud (%) 64 24.6 52.6 57.8 6.8 47.3 CaCO, (biogenic) (%) 64. 1 25 6.3 TS 10.1 I5)57/ Fe (terrigenous) (%) 33 4.4 IT) 8.6 553) 3.9 Opal (%) 0 0 32.1 0 0 19.2 Authigenic (%) 0.6 5) 3}5) 4 Swe WS *—areas indicated on Figure 25 QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 417 Area 2. Mid—outer shelf on the Walvis Ridge Abutment (mean water depth 287 m). Characterized by warm, oxygen-depleted water and mixed carbonate/terrigenous, muddy sands with a high organic matter content. Area 3. This is the most extensive of the barren areas. It lies on the inner—mid-shelf (mean water depth 93 m) and is characterized by warm, saline, oxygen-deficient waters over sediments that have high organic matter and high opaline silica contents, The sedi- ments are depleted in carbonate, Fe (= terrigenous component) and authigenic minerals. This area can be subdivided into a smaller coastal zone between 19 and 20°S (area 3A) and the main zone centred on Walvis Bay, which extends from 21°S to the vicinity of Liideritz (area 3B). Area 4. A long, narrow, inner-shelf zone off the Namaqualand coast (mean water depth 107m) that is characterized by high-terrigenous and low-carbonate muds. In contrast to area 3, the muds contain no opal and relatively little organic matter. The mean oxygen value of the bottom water is depleted (2.2 ml/l). Area 5. On the mid—outer shelf (mean water depth 218 m) either side of the Cape Canyon. Characterized by water with high dissolved oxygen values over authigenic-rich, low-carbonate sands with a very low organic content. These sediments have particularly low mean mud values. Sea bottom sediments in three of the areas (1, 3 and 4) have in common particularly high mean mud contents, but each differs in its mineralogical and/or oceanographical characteristics: the slope area | is a carbonate mud; the Walvis shelf area 3 is an organic- rich, low-oxygen mud; and the Namaqua area 4 is terrigenous mud. The other two areas (2 and 5) have low mud contents. In the case of the Walvis Ridge Abutment (area 2), it shares in common with area 3 low oxygen and high organic matter contents, whereas on the outer shelf off the Cape Peninsula (area 5) the very low organic matter—high authigenic (especially glauconite) contents are probably limiting. In summary, barren areas coincide with one or more of the following limiting factors: High mud content of bottom sediments (> 57.8%). Low dissolved oxygen in bottom waters (< 1.0 ml/l). High (> 6.9%) or low (< 1.0%) organic matter in bottom sediments. Low salinity bottom waters (< 34.47%). . High authigenic content (51.5%) of bottom sediments (which may equate with Pricilarly low terrigenous supply). A a are DISCUSSION ‘Modern’ and ‘relict’ faunas The ostracod assemblages used in the study were mixtures of living and dead specimens. The latter category presumably consisted of recently dead material, which are essentially the same age as the living specimens, and older dead specimens that represent a relict, sub-fossil fauna. In earlier accounts (Dingle 1992, 1993), a distinction was made between these ‘modern’ (living and recently dead) and ‘relict’ specimens, primarily on the basis of valve preservation. Opaque, corroded, stained and abraded valves were con- sidered ‘relict’ in contrast to transparent, pristine specimens, some containing fragments of internal organs, which were considered only recently dead (i.e. ‘modern’). 418 ANNALS OF THE SOUTH AFRICAN MUSEUM The logic applied to the analysis of these two categories was that the sea-floor sediments off south-western Africa represent a quasi-equilibrium deposit developed since sea-level reached its present position, approximately 7000 years ago (Miller 1990). Consequently, the ‘relict’ ostracod fauna is a mixed assemblage of specimens ranging in age from 0 to 7000 years—the so-called post-glacial category, in contrast to the ‘modern’, extant category. I am sure that essentially this logic is sound, but recent examination of material from a box core west of Walvis Bay (at 132m water depth, personal data) has cast doubts on the use of this technique to differentiate the two categories of differing ages. Consequently, in this report I have adopted a conservative approach by considering the fauna as a whole, so that the species and assemblage distribution data relate to ‘average’ oceanographical and other environmental parameters, typified by present conditions, but in reality representing means over the period 7 000 years to the present. The available time series for assessing such parameters is, naturally, very short. Oceanographical data Modern mean annual sea-floor temperature, salinity and dissolved oxygen values for the west-coast continental shelf were compiled for the present study from a 60-year data base by Dingle & Nelson (1993). Their maps are summarized in Figure 27, on to which have been superimposed the mean annual positions of the upwelling cells of the Benguela system (from Lutjeharms & Meeuwis 1987). The salient points from Figure 27 will be briefly mentioned. The high correlation coefficient between temperature and salinity values (R = 0.896 for all stations) means that the structure of the two maps Is very similar, although there are some differences in detail. Four main features are evident: Walvis Luderitz \ EAS 4\ P=*—~Z Namaqua ———\ \ \\ \= 4.8 \ b——,_ Columbine ——— \ ‘ ! \ We aN ==) Upwelling — \ aN i SO system iW \ \ A \ at 9 \VERY Peninsula Np Ss \ 6\O4 34.8 \.0 Lo: S) TEMPERATURE INST SALINITY \O\ DISSOLVED OXYGEN (°C) Dee \Nee (%o) 34.8 \ (ml/l) Fig. 27. Bottom water parameters and upwelling cells. A. Temperature. B. Salinity. C. Dissolved oxygen. After Dingle & Nelson (1993) and Lutjeharms & Meeuwis (1987). QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 419 1. The steep gradient along the shelf edge, where the temperature gradient in the Benguela region is typically 1°C/100m between 400 and 1000m. This is related simply to the bathymetry at the shelf edge. 2. The large intrusion of 9°C/34.7%o water on to the shelf off Namaqualand. This is attributed to a combination of bathymetry and wind stress. The main topographic features are the generally wide, deep shelf south of 30°S, and a superimposed transverse depression that crosses the shelf at 31.5°S (Fig. 1). The latter probably funnels all the cold water that wells up on to the shelf in this southern region (Peninsula and Columbine cells; Fig. 27), driven by the pumping action of the large cross-shelf wind divergences that are common in this area. 3. Sudden meridional shoaling of isotherms/isohalines. This effect is attributed to a flow of 6—8°C/34.48—34.68%o water across the shelf as compensation for surface Ekman drift caused by the perennial equatorward winds. This colder water becomes entrained in the poleward undercurrent, resulting in a progressive decrease in the meridional temperature and salinity as far south as 30°S. 4. Localized ‘hot spots’ of warm, saline water in the form of south-westerly tongues stretching from nearshore across the shelf. In the extreme south (c. 35°S) this is caused by the intrusion of Agulhas Bank water, but elsewhere they correlate with upwelling cells to the extent that they indicate downwelling events following periods of intense upwelling. Nelson (1989) has suggested that this occurs via wind-generated continental-shelf waves that enhance or suppress upwelling. The upwelled surface waters are carried northward by wind action, whereas the bottom waters are deflected southward by the poleward undercurrent. Differences in temperature and salinity patterns can be partly accounted for by their respective diffusion rates (10: 1). The distribution of dissolved oxygen in the bottom waters is most closely identified with upwelling in the northern areas. There are two sources of oxygen-depleted (< 5 ml/l) water in the Benguela region. There is an offshelf (300 m) water mass that originates off Angola and is carried southward by the poleward undercurrent (Bubnov 1972; Chapman & Shannon 1985); this extends to about 25°S (occasionally 29°S) and wells up on to the shelf in the manner described above for the 6—8°C water (item 3). The Angolan low- oxygen water is further depleted by sea-floor biochemical action under the influence of the major Walvis Bay—Liideritz upwelling cell, resulting in a large, shelf-wide oxygen- deficient (< 2.0 ml/l) zone, north of 25°S (e.g. Basov 1976; Bailey et al. 1985; Shannon 1985; Dingle & Nelson 1993). The southern limit of this area is sharply outlined by the southern 1.5ml/l contour, which corresponds with the edge of the upwelling cell (Fig. 27C). A stream of this oxygen-deficient water leaks southward under the influence of the poleward undercurrent, and forms a nearshore zone as far south as St Helena Bay. Further small zones of depletion occur by biochemical action off southern Namaqualand. In this connection, De Decker’s (1970) observation of seasonality in oxygen depletion correlates with the seasonality of the poleward undercurrent (Dingle & Nelson 1993). Relationships between ostracods and environmental parameters Having looked at the mean values of the various parameters for each species, what can be said about their overall correlations? Bearing in mind that a wide range of environmental parameters influences the distribution of Ostracoda (see, for example, Neale 1965; Whatley 1983; Brouwers 1988; Athersuch et al. 1989), it is possible that 420 ANNALS OF THE SOUTH AFRICAN MUSEUM variations in any one parameter will be insufficient to control the geographical range of a taxon completely. Nevertheless, several authors have concluded that certain parameters are likely to be more important than others. In this category, temperature has been singled out as a major factor, so much so that it was the only parameter considered by Cronin & Dowsett (1990) along the continental shelf off eastern North America, whereas Valentine (1976) concluded that faunal distribution along the Pacific coast of North America was primarily controlled by water temperature related to upwelling. Athersuch et al. (1989) considered temperature to be the main ecological control (along with salinity) in distribution around the British Isles, and commented that variations in dissolved oxygen were of little significance. Brouwers (1988), on the other hand, believed that temperature, salinity and dissolved oxygen are the main physico-chemical controls for ostracod distribution off Alaska. For comparison, Brouwers (1988) recorded the follow- ing ranges in parameters on the Alaskan shelf (south-western African values in parenthesis): temperature, 5—5.5°C (3.0—14.0); salinity, 33.00—34.00%bo (34.39—35.5); and dissolved oxygen, 3—7 ml/I (0.29—4.8). The question of dissolved oxygen and the distribution of particular marine taxa has been raised by several authors and this is a factor that is especially relevant off south- western Africa, where the whole of the continental shelf is oxygen depleted (< 5.0 ml/I), and large areas are deficient (< 2.0 ml/l) (e.g. Shannon 1985). Briefly, the structure of the vestibula of the genus Krithe has been linked to variations in dissolved oxygen levels (e.g. Peypouquet 1977; McKenzie et al. 1989; Riha 1989; Zhou & Ikeya 1992; but for an alternative viewpoint see Whatley & Quanhong 1993), whereas the physiological adaptations of certain taxa (particularly the genus Cytherella) have given them advantages in colonizing low-oxygenated environments (e.g. Whatley 1991). Other factors have generally received less attention but, nevertheless, some authors have strongly asserted their importance (e.g. Whatley & Wall 1969; Whatley 1976). In this category fall factors such as substrate types (animal, plant and mineral, as well as textural variations), pH, food supply, light levels, turbulence (i.e. energy of the boundary layer), and so on. Athersuch ef al. (1989) have reviewed the distribution of all the major taxa around the British Isles and concluded that certain taxa have preference for different substrates: Xestoleberis is primarily a phytal genus, whereas Urocythereis, Palmo- concha, Cytheropteron, Cytherura and all Trachyleberididae and Cytherideidae live on sand. However, many taxa appear to have no preference (e.g. Aurila, Loxoconcha and Semi-cytherura). Clearly, it would be an unrealistically complex operation to acquire from the whole margin off south-western Africa time-averaged data on all the factors mentioned above, even if it were certain that there were no others of significance. Spot measurements during sample collection would have served little purpose and, unfortunately, data bases on most parameters are not available. Also, the circumstances in specific geographical areas will strongly bias the likelihood of particular factors playing crucial roles. In the present case, the large range in dissolved oxygen values, the overall lack of terrigenous input, the locally high contents of authigenic minerals, and the overall intensity of oceanic upwell- ing, make the continental margin off south-western Africa, if not unique, at least one of only five localities world-wide with similar conditions (the others being California, Peru, north-west Africa and the Gulf of Arabia). Adaptation to these conditions can be expected to have played an important role in the composition of the local faunas, and QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 421 significant variations from the ‘norm’ of what has been described from, say north-western Europe or north-eastern North America, can be anticipated. In this connection, the large number of barren sites must be viewed as a response to the unusual environments, and not merely an aberration of the sampling and laboratory techniques. Considering, firstly, the relationships between the environmental parameters them- selves, Table 3 shows the correlation coefficients based on simple regression analyses between the parameters in those samples from which > 100 specimens were extracted. Here there will be a bias against deeper-water sites and areas unfavourable for ostracod colonization, where, in both cases, valve numbers are low. Some strong relationships are obvious (sand-mud, and temperature-salinity-oxygen), but the positions of MORG and CaCO; are less so. To draw out the more subtle relationships, these values have been plotted (Fig. 28) on a similarity dendrogram, using an unweighted arithmetic average clustering technique ) 20 40 SIMILARITY 60 80 100 mud sand MORG glauc. CaCO, 0, _ salin. temp. Fe apatite Fig. 28. Similarity dendrogram (unweighted arithmetic average) of environmental parameters. 422 ANNALS OF THE SOUTH AFRICAN MUSEUM (e.g. Legendre & Legendre 1983). This shows two main groupings at the 35—45 per cent similarity level. The strong antipathetic relationship between sand and mud (—0.9306) is linked to MORG through a positive correlation (0.4906) with mud, and to glauconite through a positive correlation with sand (0.3788). The second grouping is based on the strong positive correlation between temperature and salinity (0.9092) and their negative correlation with dissolved oxygen (— 0.8130 with salinity). These relationships are representative of the regional trends discussed by Dingle & Nelson (1993) and reflect properties of the major water masses and upwelling cells along the west coast (e.g. Fig. 27). They are negatively correlated with the calcium carbonate content of the bottom sediments (—0.4902 with salinity), implying that carbonate-rich sediments are less likely to occur in the warmer, more saline, sea-floor environments, as well as in outer-shelf areas where more oxygenated waters occur. Similar conclusions were reached by Rogers & Bremner (1991), who showed that the areas of most intense upwelling (between about 28° and 24°S, where bottom temperatures and salinities are particularly high) are underlain by sediments with low carbonate contents. Similarly, south of 29°S, where dissolved oxygen levels on the shelf are at their highest, low carbonate values characterize the whole shelf south and west of the Cape Peninsula. No comprehensive explanation for the latter situation has yet been advanced. Elemental Fe (= terrigenous component) and apatite values have no close links with the other two groupings (< 20% similarity). The terrigenous input to the west coast is controlled by four major factors: Kunene River input north of the Walvis Ridge; the combined input of the Orange River and of the Olifants and Berg rivers on to the Orange—Namaqua shelf; and aeolian input between the Orange River and Walvis Bay. Whereas the latter phenomenon is to some extent linked to upwelling through regions of strong wind stress, there are no direct relationships between the terrigenous sources and the environmental factors investigated. Tables 2 and 7 show which parameters are most strongly correlated with particular ostracod species. A simple gauge of which parameters are most effective in determining the distribution of species can be made by totalling the number of species most strongly correlated with each parameter. Fe and calcium carbonate rank joint first (S species each), followed by sand (4species). Amongst these, there is a preponderance of negative correlations, particularly with sand and, to a lesser extent, CaCO 3 (this conclusion is reinforced if a tally is made of the strongest positive and negative correlations for each species: sand = 13, calcium carbonate = 8, Fe = 8, and MORG = 8). The implication is that the abundance of the majority of ostracod species in the study has an antipathetic relationship to sandy and/or carbonate-rich substrates. In addition, neither temperature, salinity, nor oxygen is as important as MORG. Considering the importance of environmental parameters in terms of the regionally dominant species (Figs 10, 29), however, presents a somewhat different picture. South of 24°S, the two dominant inner-shelf species Pseudokeijella lepralioides and Bensonia knysnaensis knysnaensis correlate with the mud (positively) and carbonate (negatively) content of bottom sediments, respectively. In the case of the latter, the strongest positive correlative is Fe, indicating that increases in abundance of Bensonia k. knysnaensis are dependent on decreasing carbonate, coupled with increasing terrigenous components. Farther offshore, Ruggieria cytheropteroides is positively correlated with dissolved oxygen. North of 24°S, the two dominant species are Palmoconcha walvisbaiensis (mid— QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 423 TABLE 7 Summary of strongest correlations between species and environmental parameters. These parameters are those that most negatively or positively influence the abundance of a particular species. Species Positive Negative Cytherella namibensis MORG oxygen Bensonia k. knysnaensis Fe CaCO, Ruggieria cytheropteroides oxygen — Henryhowella melobesioides sand mud (temperature) Pseudokeijella lepralioides mud sand Palmoconcha walvisbaiensis MORG oxygen/Fe Urocythereis arcana apatite = Macrocypris cf. M. metuenda CaCO, mud Australoecia fullert Fe — Bairdoppilata simplex sand apatite Paracypris lacrimata Fe CaCO, Cytheropteron whatleyi salinity sand Cytheropteron trinodosum MORG CaCO, Cytherella dromedaria MORG sand Neocytherideis boomeri sand mud Poseidonamicus panopsus glauconite CaCO, Neocytherideis lordi MORG apatite Incongruellina venusta — CaCO, Buntonia rogersi MORG Fe Ambostracon flabellicostata salinity sand Buntonia bremneri mud sand Xestoleberis africana Fe sand Chrysocythere craticula CaCO, Fe Austroaurila rugosa CaCO, sand Doratocythere exilis apatite temperature Neocytherideis osseus mud sand Ambostracon keeleri MORG sand Buntonia gibbera MORG sand Buntonia namaquaensis glauconite Fe Note: items in bold are the overall strongest correlatives. For H. melobesioides, temperature is probably a better indicator for the deep-water assemblages. inner shelf) and Cytherella namibensis (outer shelf—upper slope), and here the strongest correlations are with MORG (positive) and dissolved oxygen (negative), respectively. The latter species’ strongest positive correlative is also with MORG, whereas the strongest negative correlative of Palmoconcha walvisbaiensis is dissolved oxygen. Consequently, both dominant taxa on the shelf off northern Namibia respond positively to increases in the quantity of organic matter in bottom sediments and negatively to increases in dissolved oxygen. Henryhowella melobesioides is the dominant species over the length of the margin in water deeper than 500 m (to about | 500 m) and this species correlates most strongly with mud (—0.5360), with sand its strongest positive correlative. However, because of the relatively small sample sizes in deep water, these correlations are biased 424 ANNALS OF THE SOUTH AFRICAN MUSEUM Kunene River P. walvisbaiensis (+ MORG) C. namibensis Central Namib (05) association ie N N \ MX Luderitz B. k. knysnaensis 30° P. lepralioides (+ mud) H. melobesioides ————~ (— mud, — temp.) association R. cytheropteroides s KC. Columbine (+ O>) i Fig. 29. Distribution of dominant ostracod assemblages (shaded, from Figure 10) and barren areas (thick outline, 1—5 from Figure 26). Dashed line is the shelf break. Parameters in parentheses are strongest environmental correlatives for dominant species (positive or negative) from Table 7. 425 QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA ‘(OUOW) Jonew s1urs1OQ ‘q ‘UuasAxo paajossiq “OD “AUTRES “G ‘anyestoduiay y ‘siojowered JUSUIpas IOOY-ves PUB J9]BM-I0}}0Q pUR sadE[qUIasse Pooeso jUvUTWOp Jo sueid ydop—opnineT ‘o¢ ‘SI 4 0001 % (1/144) 0001 (%) DYOW (S) @ no} SSS = 00s = 3 Zl wo SoGe og GZ 02 ce og Sz 02 ‘@| o 0001 0001 eee (°%) ALINITVS S$ &___-© (90) JYNLVYAdWISL aq? S WH 3" WH 0 @ 1] eo o0g = 3 0 ANNALS OF THE SOUTH AFRICAN MUSEUM 426 ‘s[RIOUIW STUSSIYINY “ “BOIS o1UaTOIg “DQ ‘a}eUOGIeO oussolg ‘gq (84) SnoUdSIAy “yY ‘siojouIeIed USUTIPes IOOY-eas pue J0}eM-WIO}}0G PUL sadE[qUIDSse pooRsO JURUTUOp Jo suRTd Ydep—opnineT “[¢ ‘Sy OOOL OOOL SINSDIHLNY (edo) OINADOIE } (lu) yidaq SNONADIYYSL QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 427 towards the shallower water sites at which H. melobesioides occurs and in which it is a less-important component of the assemblage. Correlation coefficients based on the whole sample suite suggest that this species, on a regional basis, most strongly correlates with temperature (— 0.5143) which, together with salinity, generally decreases with increasing latitude and depth (Fig. 27). It is convenient to consider the distribution of ostracod assemblages in relation to regional environmental parameters in terms of the dominant taxa. Figure 29 shows the geographical distribution of the dominant taxa, together with the environmental parameters with which they are most strongly correlated, whereas Figures 30—32 show regional latitude—depth plans of variations in all the parameters investigated. To make a more sophisticated assessment of the relationships between individual species requires a multivariate approach, and this has been presented in a separate publication (Dingle & Giraudeau 1993). 500 Depth (m) [seca 1000 4 & SAND 500 Depth (m) 1000 Fig. 32. Latitude—depth plans of dominant ostracod assemblages and bottom-water and sea-floor sediment parameters. A. Sand. B. Mud. 428 ANNALS OF THE SOUTH AFRICAN MUSEUM The general conclusions from the discussion above are that the distributions of dominant taxa in the deeper-water areas are most strongly correlated with parameters related to the water-mass properties, whereas the mid- and inner-shelf taxa most strongly correlate with sedimentary characteristics (in particular Fe (= terrigenous component), calcium carbonate and sand). These correlations do not imply that such factors are the only controls but that they are, statistically, the most important for individual species. To understand these correlations, it is important to remember that the oceanography and climate off south-western Africa are influenced by phenomena that, on a global scale, are not widely developed: intense oceanic upwelling, large-scale development of oxygen- depleted bottom water (< 5 ml/l), and low terrigenous input. SUMMARY Figure 33 shows the conceptual relationships between the distribution of the regionally dominant ostracods and the main oceanographical components of the west coast. In deep water, small-scale phenomena are subordinate to the regional water- column structure (see Fig. 2), so that the upper limit of the mid—lower-slope assemblage (dominated by Henryhowella melobesioides) is controlled by the position of the base of the salinity minimum zone in the AAIW (500—600 m) (see also Dingle et al. 1990). Higher up the slope, the effects of shelf upwelling and the intrusion of shelf currents are felt. South of 28°S, the cold, low-salinity, oxygen-rich upper section of the AATW sustains the upper slope—outermost shelf Ruggieria cytheropteroides-dominated assem- blage, but northwards this gives way to the less abundant and diverse Cytherella namibensis-dominated assemblage that is influenced by warmer, more saline, oxygen- depleted water just beyond the shelf edge moving into the region across the Walvis Ridge from the Angola Basin. Deflection of uppermost AAIW around the major bathymetric re-entrant along the northern side of the Orange Banks (27—28°S: Fig. 1) is probably a critical control in the location of this oceanic/faunal boundary. As Whatley (1991) has discussed, platycopid ostracods are particularly adapted to competing in lower-oxygen environments and, clearly, C.namibensis (in marked contrast to its more southern relation C. dromedaria), has taken advantage of this in areas that are unfavourable to most other species. Moving farther on to the shelf, the influences of water mixing and upwelling are more pronounced. In the north, the off-shelf Angolan water mass advects oxygen- depleted waters on to the Walvis—Liideritz shelf, where intense upwelling, followed by further, biologically-induced oxygen extraction on the sea-floor, creates a reservoir of strongly oxygen-depleted shelf waters and organic enrichment in bottom sediments, which is the preferred environment of Palmoconcha walvisbaiensis. Under the influence of the poleward undercurrent, strong southward temperature, salinity and oxygen depletion gradients are created (Fig. 27), which progressively support different ostracod associ- ations as the properties of the southward-moving water change, and it interacts with other, colder shelf waters in the vicinity of the Orange River. Hence, the Palmoconcha walvisbaiensis-dominated assemblage passes via a mixed zone (Central Namib association) into the coast-parallel assemblages dominated by Pseudokeijella lepralioides (positively correlated with mud) and Bensonia k. knysnaensis (negatively correlated with mud and positively correlated with Fe). depth (km). OXYGEN-POOR WATER ooo Off shelf edge Angolan source Depletion under upwelling cells ee Warm saline water Cold, low-salinity water Low juvenile : ratio adult HM top of salinity minimum zone: AAIW incursion of cold water onto Namaqua Shelf association, CB = Childs Bank. QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA if >---- ~ pe Sal Po 1 8 een s easing !. SS er oe en Agulhas filaments (Sa = [= PW o So a= S| oO X\ 37 o-_ a! Ory eC ale ne o| oF] es I ra) Bas Seal G5 “I Bea) aS O; Epa a 12) TE 5 el oH en a eS) ®| ol] v.. = |) me) \\ OS c Se SI e © g ue el \ °> <| © .- rae > f@eccecescececcece e@02000000000008 429 20 Fig. 33. Conceptual relationships between ostracod associations and the main oceanographic regimes and features plotted on a latitude—depth plan. Vertical scale is degrees of latitude, horizontal scale is water Abbreviations: BKK = Bensonia k. knysnaensis, CN = Cytherella namibensis, CNA = Central Namib association, HM = Henryhowella melobesioides, PL = Pseudokeijella lepra- lioides, PW = Palmoconcha walvishaiensis, RC = Ruggieria cytheropteroides, SWCA = South West Cape 430 ANNALS OF THE SOUTH AFRICAN MUSEUM The southern limit of oxygen-deficient water, together with intense upwelling of upper-level AATW off the Cape Peninsula and intrusions of warm, Agulhas water filaments (Lutjeharms 1989), combine to produce the particularly diverse and abundant, but geographically small, South West Cape association. Other aspects of interest are the high degree of strongest negative correlation with the sand content of the bottom sediments (13 (negative) : 3 (positive)), and the high degree of strongest positive correlation with the MORG values (8: 0) (Table 7). These contrast with more equitable correlations with the terrigenous (Fe) and biogenic (CaCO3) components (4: 4 and 3:5, respectively). The implications from these relationships are that the abundances of a large minority of species (34% in Table 7) are affected adversely by increases in the ambient sand content of their favoured substrates, the exceptions being Henryhowella melobes- ioides, Bairdoppilata simplex and Neocytherideis boomeri. Although few details have been published on bottom currents on the west-coast margin, indications are that they are generally low and poleward. Nelson (1989) suggested that, between Cape Point and the Orange River, a vector-averaged poleward velocity of 3.8 cm/sec exists, but noted that at 66 m off Chamais Bay (28°S) a current meter has recorded a long-term average of 1.7 cm/ sec north-west. Only along the outer Namaqua shelf, between 31°S and the vicinity of Cape Columbine (33°S), is there possible evidence for relatively high-velocity currents in the Benguela system (the Shelf Edge and Columbine jets), with surface velocities up to 40 cm/sec north-west (e.g. Shannon 1985; Nelson 1989). However, although Shannon (1985) suggested that these may have subsurface effects, Nelson (1989) indicated that they are merely high-velocity streams (40—50 cm/sec) in the general northward Benguela surface flow pattern (which itself varies from 5 cm/sec over the shelf to 30 cm/sec beyond the shelf edge). Strong and turbulent bottom currents are not, therefore, anticipated over any large part of the west-coast shelf, and few species can be expected to have adapted to such conditions. Perhaps this explains the susceptibility to increases in sand content (if it denotes somewhat higher bottom-water energy). A further assessment of areas with high-velocity sea-floor currents can be related to possible post-mortem valve transportation. Figure 34 shows the latitudinal distribution of sample sites plotted against their juvenile : adult ratios. Sites with the lowest ratios are intuitively taken as those most subjected to higher sea-floor winnowing, and these all occur south of 30°S. The most-affected sites lie in water depths between 205 and 271 m in the vicinity of Childs Bank (see Figs 1, 33), where Nelson (1991 pers. comm.) has suggested that an extension of the Shelf Edge Jet could operate, although it should be emphasized that other sites on the mid—outer shelf in this area have ratios between 6 and 8 : 1. Winnowing is further suspected at two sites on the inner shelf, immediately west of the Cape Peninsula (120—140 m at 34°S, Figs 33, 34) and at an inshore site (42 m) near Cape Columbine (32.5°S, Fig. 34). In contrast, all sites north of Childs Bank as far as the Walvis Ridge, suggest quiet sea-floor conditions, as do the bulk of the sites off the Cape Peninsula. No species has the organic content of bottom sediment as the parameter most adversely affecting its distribution, whereas an increase in the MORG value favourably affects 28 per cent of the taxa in Table 7, with Palmoconcha walvisbaiensis, Ambostracon Keeleri and Buntonia gibbera particularly sensitive in this regard. On a continental shelf where the organic content of sediments is generally high and, overall, the most organic QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 43) 16 14 = 12 = 2 =o J 5 - : a) so 8 = ne | r x = = a ne oo) a = = = = a aaa ca = = = = ae 4 = CHILDS BANK 2 0) 18 20 22 24 26 28 30 32 34 36 Latitude (°S) Fig. 34. Latitudinal distribution of juvenile: adult ratios in samples containing > 100 specimens. Sediment partitioning by bottom currents is progressively indicated by ratios < 5 (see Brouwers 1988). This phenomenon is suggested at the sites with water depth > 200 m in the vicinity of Childs Bank. rich in the Atlantic Ocean (Yemel’yanov 1975, quoted in Rogers & Bremner 1991), the ability not to be affected adversely by increases in MORG is clearly an ecological advantage. Finally, in the distribution of barren samples (see Fig. 27), the direct and indirect effects of upwelling are probably the dominant influence north of 27°S (dissolved-oxygen values < 1.0 ml/l, MORG values > 6.9%), whereas fluvial input (area 4: terrigenous mud values > 58%) and topography (area 5 either side of the Cape Canyon, which shelters areas from organic-matter sources, and perhaps creates locally unfavourably strong sea- floor currents) are important in the south. ACKNOWLEDGEMENTS This work was funded by research grants from the Foundation for Research Development and South African Museum, for which I am grateful. I have benefited from discussions with numerous colleagues, but in particular would like to acknowledge Dr J. M. Bremner (University of Cape Town) and Mr G. Nelson (Sea Fisheries Research Institute). Professors Lord (University College London) and Whatley (University College Aberystwyth), and Dr Oertli suggested improvements to the manuscript. Oceanographic data, upon which many of my conclusions are based, were originally supplied by the South African Data Centre for Oceanography, and I thank the Director, Dr M. Grundlingh, for his generous assistance. I also thank Mrs J. Woodford who drafted most of the figures, and Ms L. Bisset for photography in connection with the plates. 432 ANNALS OF THE SOUTH AFRICAN MUSEUM REFERENCES ATHERSUCH, J., HoRNE, D. J. & WHITTAKER, J. E. 1989. Marine and brackish water Ostracoda. Leiden: E. J. Brill. Battey, G. W., Beyers, C. J. & Lipsitz, S. R. 1985. Seasonal variations of oxygen deficiency in waters off southern South West Africa in 1975 and 1976 and its relation to the catchability and distribution of the Cape rock lobster Jasus lalandii. South African Journal of Marine Science 3: 197-214. Basov, I. A. 1976. Peculiarities of the quantitative distribution of foraminifera in the bottom sediments of the south-west African shelf due to upwelling. Oceanology 16 (2): 153-155. BENson, R. H. & MaAppocks, R. F. 1964. Recent ostracods of Knysna Estuary, Cape Province, Union of South Africa. Paleontological Contributions. University of Kansas 34 (Arthropoda, Article 5): 1—39. Bircu, G. F. 1975. Sediments on the continental margin off the west coast of South Africa. Bulletin. Joint Geological Survey—University of Cape Town Marine Geoscience Unit 6: 1—142. Bircu, G. F., RoGers, J. & BREMNER, J. M. 1986. Texture and composition of surficial sediments of the continental margin of the republics of South Africa, Transkei and Ciskei. Map of the Geological Survey of South Africa, Marine Geoscience Series 3: sheets 1—4. Brapy, G.S. 1880. Report on the Ostracoda dredged by ‘HMS Challenger’ during the years 1873-1876. Report of the Scientific Results of the Voyage of HMS Challenger 1873—76 (Zoology) 1 (3): 1—184. BREMNER, J. M. 1980. Physical parameters of the diatomaceous mud belt off South West Africa. Marine Geology 34: M67—M76. BREMNER, J. M. 1981. Sediments on the continental margin off South West Africa between latitudes 17° and 25°S. Bulletin. Joint Geological Survey—University of Cape Town Marine Geoscience Unit 10: 1—233. BREMNER, J. M. 1983. Biogenic sediments on the South West African (Namibian) continental margin. Jn: THIEDE, J. & Suess, E. eds. Coastal upwelling: its sedimentary record. Part B: Sedimentary records of ancient coastal upwelling: 73-103. New York: Plenum Press. BREMNER, J. M., RoGers, J. & BircH, G. F. 1986. Surficial sediments of the continental margin of South West Africa/Namibia. Map of the Geological Survey South West Africa (Namibia), Marine Geo- science Series, 16 maps on 4 sheets. BREMNER, J. M. & WILLIS, J. 1993. Mineralogy and geochemistry of the clay fraction of sediments from the Namibian continental margin and the adjacent hinterland. Marine Geology 115: 85—116. Brouwers, E. M. 1988. Paleobathymetry on the continental shelf based on examples using ostracods from the Gulf of Alaska. Jn: DE Decker, P., CoLin, J. P. & PEypouquet, J. P. eds. Ostracoda in the earth sciences: 55—76. Amsterdam: Elsevier. Busnov, V. A. 1972. Structure and characteristics of the oxygen minimum layer in the southeastern Atlantic. Oceanology 12 (2): 193-201. CHAPMAN, P. & SHANNON, L. V. 1985. The Benguela ecosystem. Part II. Chemistry and related processes. Oceanography and Marine Biology. An Annual Review 23: 183-251. Cronin, T. M. & Dowsetrt, H. J. 1990. A quantitative micropaleontologic method for shallow marine paleoclimatology: application to Pliocene deposits of the western North Atlantic. Marine Micropaleontology 16: 117-147. De Decker, A. H. B. 1970. An oxygen-depleted subsurface current off the west coast of South Africa. Investigational Report. Division of Sea Fisheries, South Africa 84: 1—24. DINGLE, R. V. 1992. Quaternary ostracods from the continental margin off south-western Africa. Part I. Dominant taxa. Annals of the South African Museum 102 (1): 1-89. Dinc_e, R. V. 1993. Quaternary ostracods from the continental margin off south-western Africa. Part II. Minor taxa. Annals of the South African Museum 103 (1): 1—165S. DincLe, R. V. & GiRAUDEAU, J. 1993. Benthic ostracods in the Benguela system (SE Atlantic): a multivariate analysis. Marine Micropalaeontology 22: 71—92. Dinc_e, R. V. & Lorp, A. R. 1990. Benthic ostracods and deep water-masses in the Atlantic Ocean. Palaeogeography, Palaeoclimatology, Palaeoecology 80 (3—4): 213-235. Dincie, R. V., Lorp, A. R. & Boomer, I. D. 1989. Ostracod faunas and water masses across the continental margin off south-western Africa. Marine Geology 87: 323-328. Dincie, R. V., Lorp, A. R. & Boomer, I. D. 1990. Deep-water Quaternary Ostracoda from the continental margin off south-western Africa (SE Atlantic Ocean). Annals of the South African Museum 99 (9): 245—366. DincLe, R. V. & Netson, G. 1993. Sea-bottom temperature, salinity and dissolved oxygen on the continental margin off south-western Africa. South African Journal of Marine Science 13: 33—49. Gorpon, A. L. & Haxsy, W. F. 1990. Agulhas eddies invade the South Atlantic: evidence from Geostat altimeter and shipboard conductivity-temperature-depth survey. Journal Geophysical Research 95: 3117-3125. QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 433 Hart, T. J. & Currie, R. I. 1960. The Benguela Current. Discovery Report 31: 123-298. HARTMANN, G. 1974. Teil III. Die Ostracoden des Untersuchungsgebiets. Jn: HARTMANN-SCHRODER, G. & HARTMANN, G. Zur Kenntnis des Eulitorals der afrikanischen Westktiste zwischen Angola und Kap der Guten Hoffnung und der afrikanischen Ostkiiste von Stidafrika und Mocgambique unter besonderer Berticksichtigung der Polychaeten und Ostracoden. Mitteilungen aus dem Hamburgischen zoologischen Museum und Institut 69 (Erganzungsband): 229-520. Kure, W. 1940. Ostracoden von der Ktiste Deutsch-Stidwest-Afrikas. Kieler Meeresforschungen 3 (2): 404—448. LEGENDRE, L. & LEGENDRE, P. 1983. Numerical ecology. Amsterdam: Elsevier. LUTJEHARMS, J. R. E. 1989. The role of mesoscale turbulence in the Agulhas Current. Jn: NrHouL, J. C. J. & JaMarT, B. M. Mesoscale/synoptic coherent structures in geophysical turbulence: 357-372. Amsterdam: Elsevier. LuTyEHARMS, J. R. E. & Meeuwis, J. M. 1987. The extent and variability of south-east Atlantic upwelling. Jn: Payne, A. I. L., GULLAND, J. A. & Brink, K. H. eds. The Benguela and comparable ecosystems. South African Journal of Marine Science 5: 51—62. McKenzig, K. G., MAJORAN, S., EMANI, V. & REYMENT, R. A. 1989. The Krithe problem — first test of Peypouquet’s hypothesis, with a redescription of Krithe praetexta praetexta (Crustacea, Ostracoda). Palaeogeography, Palaeoclimatology, Palaeoecology 74: 343-354. Miter, D. E. 1990. A southern African late Quaternary sea-level curve. South African Journal of Science 86: 456—458. MU ter, G. W. 1908. Die Ostracoden der Deutschen Stidpolar-Expedition 1901—1903. Wissenschaft- liche Ergebnisse der deutschen Stidpolarexpedition 10 (Zoologie, 2): 51—181. NEALE, J. W. 1965. Some factors influencing the distribution of Recent British Ostracoda. Pubblicazione della Stazione Zoologica di Napoli 33 (suppl.): 247—307. NELson, G. 1989. Poleward motion in the Benguela area. Jn: NesuyBA, S. J., Moorrs, C. N. K., Smitu, R. L. & Barser, R. T. eds. Poleward flows along eastern ocean boundaries: 110—130. Berlin: Springer. PeypouaquET, J. P. 1977. Les Ostracodes et la connaissance des paleomilieux profonds. Application au Cenozoique de |’Atlantique nord-oriental. Unpublished thesis, University of Bordeaux. Rina, J. 1989. Ostracod interpretation of palaeodepth of Miocene (Lower Badenian) calcareous clays near Brno, Czechoslovakia. Courier Forschungsinstitut Senckenberg 113: 103-116. Rocers, J. 1977. Sedimentation on the continental margin off the Orange River and the Namib desert. Bulletin. Joint Geological Survey—University of Cape Town Marine Geoscience Unit 7: 1—162. Rocers, J. & BREMNER, J. M. 1991. The Benguela ecosystem. Part VII. Marine-geological aspects. Jn: Barnes, M. ed. Oceanography and Marine Biology. An Annual Review 29: 1-85. SHANNON, L. V. 1966. Hydrology of the south and west coasts of South Africa. Investigational Report. Division of Sea Fisheries, South Africa 58: 1—52. SHANNON, L. V. 1985. The Benguela ecosystem. Part I. Evolution of the Benguela, physical features and processes. Jn: BARNES, M. ed. Oceanography and Marine Biology. An Annual Review 23: 105—182. SHANNON, L. V. & Hunter, D. 1988. Notes on Antarctic Intermediate Water around southern Africa. South African Journal of Marine Science 6: 107-117. SHANNON, L. V., LuTJEHARMS, J. R. E. & Netson, G. 1990. Causative mechanisms for intra-annual and interannual variability in the marine environment around southern Africa. South African Journal of Science 86: 356—373. STANDER, G. H. 1964. The Benguela Current off South West Africa. Investigational Report. Marine Research Laboratory, South West Africa 12: 1-122. VALENTINE, P. C. 1976. Zoogeography of Holocene Ostracoda off western North America and paleoclimatic implications. Professional Papers. United States Geological Survey 916: 1—47. WuatLey, R. C. 1976. Association between podocopid Ostracoda and some animal substrates. Abhandlungen und Verhandlungen des naturwissenschaftlichen Vereins in Hamburg (NF) 18-19 (Suppl.): 191—200. Wuat_ey, R. C. 1983. The application of Ostracoda to palaeoenvironmental analysis. Jn: MADDOCKs, R. F. ed. Applications of Ostracoda: 51-77. Houston: University of Houston Geosciences. Wuat ey, R. C. 1988. Population structure of the ostracods: some general principles for the recognition of palaeoenvironments. Jn: De Decker, P., Coun, J. P. & Peypouquet, J. P. eds. Ostracoda in the earth sciences: 245—256. Elsevier: Amsterdam. Wuattey, R. C. 1991. The platycopid signal: a means of detecting kenoxic events using Ostracoda. Journal of Micropalaeontology 10: 181-185. Wuat_ey, R. & QuANHONG, Z. 1993. The Krithe problem: a case history of the distribution of Krithe and Parakrithe (Crustacea, Ostracoda) in the South China Sea. Palaeogeography, Palaeoclimatology, Palaeoecology 103: 281—297. 434 ANNALS OF THE SOUTH AFRICAN MUSEUM WuatLey, R. C. & WALL, D. R. 1969. A preliminary account of the ecology and distribution of Recent Ostracoda in the southern Irish Sea. Jn: NEALE, J. W. ed. The taxonomy, morphology and ecology of Recent Ostracoda: 268—298. Edinburgh: Oliver & Boyd. YEMEL’ YANOV, Y. M. 1975. Organic carbon in Atlantic sediments. Doklady Akademii nauk SSSR 220: 220-223. ZuHou, B. & IkeyA, N. 1992. Three species of Krithe (Crustacea: Ostracoda) from Suruga Bay, Central Japan. Transactions and Proceedings of the Palaeontological Society of Japan (new series) 166: 1097-1115. 435 QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA SH ra fon) Geen RESIS sin SESS ST Shere aha PRE CISES Belen Ble: ss ES 00 0 0 LECT 81°97 90°€T 79°EL 6r'Z BL 8P'Z 9L'T Lv'0C BL IL Lama CLE LE? 60'Te Iss SLI 19°] Lye tr'0 LS’ 10 CL bE 60°T tl6 ‘as aseloAy 00! 0-0 0 0 OCS ee 78 P1 TEST 6 SoS LY cor bl L380 ve oe 01-0 97 E 8e°7 £°68°$ 91 St 17 +09 Lae col 6t 7 BS Peep OT SEE L6 ‘0 IL7-ST 81°79 vSl 89°L'0 L9°1 L95E I'tL0 8L'0 Ste 6679 pe 60°00 SL vt 9L'71-90'8 c0'1 LYV'6 adury ‘as adPlIAY 001 piduruey = LZ p :adejuaoiad |[e19AQ aduryy 7 ‘duryuey OomaAaz=n + DWOORD-M SaoSaAN SSH—rno¥naAyrAo + AQ lon) aoNts) f cO'T v1'6 Ke (ss ddRIOAY 00! 127 sodejuaosad [[Rs0aQ 0-0 0 0 redo 0-0 0 0 0-0 0 0 tedo 9TS toll L8°€Z pny VTS O'L 7O'LT €7°S7 67S6L I'S IS°SZ pnw Ce 16S Lp Stl S8°eL pues VIE S Le 19°91 8 bl 9916S Lp LL YI 9p PL pues 9 E1560 67'€ 96'¢ ayuoydsoug 6 TI-¢0 L8°€ 8S'€ 6ITeO0 pe 87'E ayoydsoyd 01-0 60'7 bl ey 01-0 Lv? v 01-0 60° ce aytuoone| 5 col 7127 19°89 00) 8) TIL SOT I8°LI 6S 87 CTLS'9L SeLt 6S 6P foor9 (EG (Ge! 6S'¢ ed LE 671 8L'P L& fel 69° ed bESEST7E BLT Pie opnyney BS Pe £967 = =BLT IZ €e LL'Pt-€9'67 981 eee apnqney SOt-OP 66S rs widaq 00¢-OF LS°@L €ST 00€-0r €L'OL 6r1 widaq 89°70 IST Ste Jayew o1ues1Q, Boel Tet 8E€ 8 oe! LOT gle JoyeW STURSIO Vel 790 eS'€ uaskXxo paalossiq Tv st v0 [EAS Cr v0 EE uasAxo paajossiq bO'SE-SS HE im) tL've Ayturyes PO SEO be ITO Lve PO'Se Ope ITO TL PE Ayres 6'ZI-L Il'T P16 ainjesadwiay, 67S L 671 LEG GICTESEL Iv'l Iv'6 ainyesaduia yf, asuey ‘as adelaAy oduey ‘as aseloAy asuey ‘as asPlaAy TIV OOoT TIV (O88 ‘Apeig) sijixa asayiXo0jD10q ¢ :suruey = ¢6'Z :adejuaosad [pe19aAG (O8ST ‘Apeig) DUDpaworp DjJadayIKD 10°00 ~~ Z00°0-—- 2000°0 Tedo 1-0 810 £0°0 1-0 810 £0°0 redo 95CSaIe 97 El £17 pnw V9r- TZ PT LI >6'67 T9valac. TL8ES1 LOZ paw 6'S6-6 bE 80°ST GEL pues 6'S6-8° ES Sol 9°69 6 See Lp (anal £8°89 pues TIt-¢€°0 pL? 90° ayuoydsoud 6480 bye ¥9'€ 6S790 I 8L°6 ayuoydsoyd 6L-0 8'r1 89'P aytuoone[f) 70 (6m0) I 70 6S'0 L490 aytuoone[H P1662 ONCE 16°79 foro £6876 ZI 9787 99°0S £6867I 766I 8 Ly fooro La 9S'1 87 ad iZe EEaL SL’ II-Z EEcc 10'S ed LL've-ty Ot BE Sp Oe opnyney BS PE TTSt Ste 80'TE LLYe 61 6l fF 90°67 apniney £0¢-SI S8°0L 79T widaq 98I-ST pIe9 orl £87-SI SOIL Stl yidaq Ls 0 6L'1 9c'¢ Jaye o1ued1O, PLlo 617 cO'F 88810 siz I8'€ Jaye s1uRSIO trl 0 70'1 v0’ uadXxo paaossiq Lame 16°0 SO'e £7600 ell £S°7 uashxo paalossiq else pS pe tl 0 OL ve Ayiures vO'SE9' PE £10 SLPE 8Iseo re 910 78 "PE Ayres S867 L Oke 19°6 aunesadwa |, 6c L vl tL'6 8ST ETL cl Te'Ol aunqesiadwea [, adury ‘as adRIaAy aduey ‘as aavioay asuey ‘as asPlIAYy TIV 001 TIV Z661 ‘a[suIq Majaay (‘¥) UooDAISOquy ¢ :durjuey = gp'¢ :adeyuaosad |pe12aAQ (PO6] ‘SYOOppRWW % UOsUag) SiswaDUSdUY “y DIUOSUag 0-0 0 0 jedo 0-0 0 0 0-0 0 0 iedo 6't9°L'9 LO'¢1 96°97 pnw tS 6'L LGD Ltt (SAS AGA S| Pest POA 196-1 9¢ LSP b0'7L pues 9166 8t IS'tl CSEL V961°9€ Ltr BL IL pues 6 Srt'0 ce'9 66'P ayuoydsoyud 6'SP-£'0 67 te’ 6 Stt'0 tL 89'b ayuoydsoyd 98-0 6S 02 9°01 aytuoone[ 01-0 p8°7 t coo 66 87 Pr aytuoone| 6769 1792 pI9S foor) 6° 76-S 9] pL? LS'S9 676 PT §9°97 L9"eS meye)ue) LI (en 7B'E cet Le It] 88'¢ S67? 79" cl | Se'Se-76 61 = 10 fb 6L'67 Ss 8S PE-1661 §=60'E 86°0t PTSE-O1 OI 88 ze'Oe opmye’y] 065-6 6 601 OLZ yidaq 1Lt-0b £°7S IZI OOS-OF LI bl 481 ded pr 01-60 66'1 PL'¢ Jaye o1urdiQ Si9zeal 9S" I See 16°60 86'1 CLS JOLLU DULTIO orl o L460 ve" uadAxO padlossiq Tel'0 ILO te Srl 0 10'T 90°E UasAXO Parfossiq BU Se-6r Pe = S10 69' Pe Ayres 87 SEO bE Amo) PL Pe 87 SEO PE FTO SL be AUS 6r ZIT 6c'l 8S°8 aunqesad way, Orclslwe Srl tt'6 67I-SS9 67 SS'6 aunqeiadway, odury ‘as adRloay adury “as advioay adury aes QsRIoAy TIV 001 TIV (ORR ‘Aprag?) saplodaldosoyshd DLAISINY | ‘duryury ZT pe iadvjuaosad |[v19AO (OBST ‘Apeagy) seproypadoy Pyohayopnesd ‘sudWIOAds (QO << YIIM SOUS = OO] ‘19S wep [NJ = WIV “(so1oads g¢) uoNLindod poov.syso Jo Juad Jad CE IO} sIQ}AWRIed [LONSNLIS XIGNdddV ANNALS OF THE SOUTH AFRICAN MUSEUM 436 6 COIL Loe LS’ PEO TT 00t-S1 ZI sduryury si 4h S S + a) 5S coaaa Sot So foe) N ZB] :adejuaolad [[e1aAO ‘as OO! O] ‘dsuryuey = QZ sadejUdoIAd []LIIAQ, g :sunjuey -AN ARMANMNHOTSO AAKMOOTTHTANN 0 0-0 0 0 redo 0-0 0 0 8-0 pL IZ Le'6 tedo CL'07 Lor9o's vil V6! pnw 6LEL tr'0 SSL 196S9 8617 PSPC a OC 6L 1966 be £191 cS'SL pues 06-6°8t £1 9¢ SP'b9 L069 pve IZ 6S°S9 pues SO'P TLI€0 on'Y LS'P ayoydsoyd 6160 1L°0 vil 805-0 IZ‘01 LOL ayuoydsoyd pre £8°0 97ST IS'S] aytuoone[H 10'0-10°0 0 10°0 L’6l-0 CS 791 ayuoone|[ SEOs 6 to tI L 6L°87 1S'6P i 0)0) 0) LSL9 bl 820 SI°SL Ses Fl Of 68 °9f fooro vTP L@ 19° vey ad LY Eat S 660 SEC 6S’ ed 87 TE LOVESTCT BT E 66'1e opnyney S097" 1661 ve (18746 TL 9TES LI LSC SEmG apniney 891 SpsSl 1871 661 yidaq OOT TE 78°98 L7I O87 SI L719 rel yidoq PLT 6S-S'°0 (esa 9S°7 Joyeu s1ued1O Crh vl S67 SLI9T 1 =SO'b 8L'S Joye o1uediO Se chal 160 7S’ ~~ uadAXO paajossiq SSIL0 60 86'0 91-70 = LEO L8'0_ —_- adAXO podjossiq 69° PE SES bt 110 69° Pe Ayiurpes 8c Seco be =O 0 90°SE ewe Seo be 8610 Piste Ayuryes 10°6 91s 6S'1 88 ainqesodway, OL 71S 01 £71 7611 PI-S'8 971 ra aunyesodwa f, OdPIOAY adury ‘as dPIOAY asuey ‘as dSPIOAY aduey ‘as adeRlOAY TIV OOT TIV (0881 ‘Apeig) xajduas vivjiddopaing I] :dunjuey = 96] sadeyuaosad [[e19AG (pL6| ‘uURLUeH) SIsWwalpgsiapoM DYQUOIOU|D_ 0 79-0 96°01 +61 ledo 0-0 0 0 0-0 0 0 [edo 6 P~ VCS? 97 Fl L761 pnw 97S6'L 98°F pr’ 8e FU 6L ILI 61 'S7 PNA 80°bL 6 Set LP Orb tpl pues 16S Lp tr'rl OIL 16S Lp Lil 6L IL pues Iv'Z 8'0S-S'0 60°11 96'P ayuoydsoud L38-¢'0 767 I8'¢ 6SreO 88 0l 89 ayuoydsoyd 60'7 01-0 (394 LIT aytuoone| oll 90°¢ 4 c-10'0 t6'L b6't ayuoone[ 60°96 £°68-€ 81 97 £7 81°6S 00) 0) £68 Ce b6'6l 10'6S CiO8ac. Sle score Le9s foro L9'P Le b8'1 vey ad LG Ceal Oly Lae vel Il'p a | LONG LL beth 07 BP £L'67 apnyney 8S Pe-Th 8% LIT tO’ LLbe-S7'7CU BE’ l6'le opmney Oel €77S1 p8 6S 871 widaq IL@-OF BEES PSI Sbs-OP LY't6 O81 yidaq roe 79I-L'0 Ce 9C'P Joye o1ues19, 8 oe l LL'I TES 89-¢ 1 99°1 Soe Joye o1uediQ GAS) t¢-L0 Coal SLC uadkxo parlossiq Laas SPO Ist Ly 6L'0 8r't uadhxo paalossiq SLbe tl Seo be 81°0 18 pe Ayuryes bO'St-9' phe ITO CL’ bt PO'SE-9O' bE TIO CL Pt Ayutpes t9'6 LE STaIL ¢9'I L101 aunjesadwia ], Grolalae Stl tr'6 OrcleLeSe SOSA £¢'6 aunyesaduua [, SRIOAY asury a's asRIdAY odury as adRIIAYy aduey as aseloAy TIV OOT TIV (O88t ‘Apesg) vivisooljaqoyf (*¥) Uoovisoqupy 6 :suruey = 67 adeyUa.IAd [;RI9AG ORR] ‘Apes puDai/d siuqajoisax 0 0-0 0 0 redo, 00 0 0 0-0 0 0 1edo (Gm a6 9CS-L'8 b6 TI 6r IZ pnw 9°tS-9'ET 6l'SI Lee eeSlL9 6S'SI 810e pnw OLL tle Lp 16°71 C'8L pues Py 98-S'Lh LISI $S'69 CLEC Ip = PSS L789 pues StU 8:9°9'0 tO? 677 ayoydsoyd 611-80 LY'Y 19° TLI9'0O 8th CUP ayuoydsoud 80 £0 8L°0 IT oyuoone| SI 69° PT [ANC £80 S9' PZ tr bl eytuoone| 9b'S9 6 76S 91 GALE be @9 fooro 6 76S EE 8h PZ pe'e9 6766 9187 PL’ SP foord 60'P Ile 60'7 t9'P 9d Lt orl 98°P L60 y9'I vy'y od 90°% £6 Pe S6 Le 97 LIEZE apnjyney 8S Peer 8t = LB'T 90°tt LO peel 6l LBC LGA opnyney hal L7Z-OP SoS pr yidaq OOE-ST 9¢°69 Tel Spo SI 8681 L9Z yidaq 87 89810 CO 6S 7 Jayew o1ues1O 899'1 (Abré LO'Y 6460 £0'7 S0'P Jaye s1uP dC, VERE trol ps0 P9'' uashxO paalossiq 1 aa 10 9'£ t'78'0 80 OP't uadhxo paalossiq Lye PO SEO PE 110 CL YE Ayurpes PO'SE-9' bE 710 IL’ be Ise-6e' pe SIO 99° PE Ayres 60°6 6CI-VL LUT rt'6 ainqesadwia |, 6TI-S'L 611 726 Or'E1-69'h 8L'I 9°8 aunyesadwia | adRIIAY odury as adPIIAYy aduey as adeloAy aduey ‘as adRloay TIV OO! TIV €1 7 :adejuaosad [[e19AQ Z661 ‘a[3uIq Mawoog siapiuayiKo0any L :Buryuey = 77 :adejuaosad |[e19AG Z661 ‘a[suiq ipuLon] sludkovs0d 437 OL PEO VE £60I-S 8 Ss TENT, LaaXeri =o4 = Seal orl OL Sb LL'Z 670 S00 bL'0 ‘as 001 koa) =a SHrmHamaswo ae Valeale! oe SpA Sen ey val ‘el asvloAy QI ‘dunuey 66° ‘adejuacsad [pe10AQ, 0 £6°97 9ICL ST c £7 6S bev 90'TE CST vL't LOE OL vt S9°6 IdRIOAY QI ‘duryury 69") ‘adejuaosad [[e19AG 0-0 0 0 redo 97-17 8rst soz pnw 6 S6-S'LP Siete = HEGEL purs 8'L°8'0 7L'Z €2 auioydsoyd (cm 99°71 = LT'9 aytuoone[ 6 767 SI 98°St S0'9b 70 )0)0) Le 17 9E'S a4 LLVE-BL'0E = 60" 78£€ apne SPS-8S Sel LSI yidaq 89-L0 Wee €9°€ Jayeul o1uez10Q, Live Iv'0 pL'€ —_ uadAxo paajossiq OL rE9O'rE ~~ =—S0'0 LOPE Aqwuryes 6 OIL'S cal 90°6 ainyeradwiay, osuey ‘as aseloaAy ‘TIV €661 ‘a[3uIq snasso sajipnyz0aN at) €38'0 L1'0 edo OTS-E'L BZ rl = LL'IZ pnw DIES LY SSE LPL pues 9° 17-€'0 9E°S £6°€ ayuoydsoyd OI-10°0 €S'Z 6S'1 ayuoone|5 C68 1'LZ 8eI% 6119 eye) (Ee Ly'l 86°€ ad C6 PEEP OT «19° 9€'0€ apnyney LU-SI 90°9S €SI wndaq Vere'l Lt 80°F Joye o1ued1Q €rL'0 Tal 90'€ — uadAxO paajossiq pIse-O're 910 8'rE Aturyes Grelalee: 90°7 £66 ainqerodwiay, aduey ‘as adRIOAY TIV C661 ‘a[sulq YUNIAD StasayIKI0L QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA pl ‘durjuery ‘as OOT 0 SLLI £e°9L OI'e £E°C 19°€S bre 6L'87 £61 90°£ 10'¢ LL'vt St'6 adeloAy OL’ | ‘adejuaosod |pR19AG 0-0 0 0 ledo GS LI-S'9 SI 9I 98 °ST pnw 16S 7 S6'SI L0'69 pues 8°0S-b'0 IL'8 +0'°9 aoydsoyd 6L°0 (ama! vs ayuooney|y 6 COP pp’ sz CESS fooro 6-60 99'1 89'£ od LL vee LI (BS P6'S7 apniney 9ELSTI Ctl G8? yidaq 880 b0'7 (an) JOB O1URsIC, L'y9'0 (43, C2 uadAXO padlossiq] RUSE PE £70 6L' ve AyuiyEs OP EI-S'S pez SL'6 ainjesadwia y, adur yy ‘as adeioay ‘TIV Z661 ‘OdUIC Sysuaqnupu D]JasayIKD VLVd LNAIDIANSNI odury “das adPIIAY OOT LI :3uryuey 99. :adeUdOIAd [feI9ZAG tr Se-Le'LI SL PE -6t PE TIV 0 redo, TS IP pnw £S°8S pues ce ayoydsoyud CIGl a}1uooney]f) 0S foro S8€ ad SL°87 apnqyey pes widaq B8°E JaVW D1URZIO PO’ uazAxO padjossiq PS re Ayrurpes 8z'9 ainjesodwiay, asevloAy 0661 ‘J9WOOg 2? ploT ‘a]3uIG sisuadvo ayy 0-0 0 0 0 0 redo O°CSr6rL 60°71 CEES Ler 18°97 pny 16S Ly TTI €9OL P0'ST PTL pues tIss0 177 8I'' 89°T 60°E auoydsoyd 01-0 £0'€ lac 697 t aytuoonr[DH 6'76-S'9T 61 £7 88°99 9E 17 86°S9 fooro Lae tI S8'e cl PSE ed 8S PE IP 8% pet CSTE PUSEIh 8 LPT 98° TE Spnynyney IL7-OP 81 ps 9LI SETS LLI yidaq 89°C T 6ST PoE 8L'1 PS’ JaeU M1uRsIO, V¢-S'°7 8c°0 C956 cr'0 6S'f UISAXO PIAlOssiq P0'SE9 bE 10 IL ve 110 PL be Ayres 6CTITL 86°0 116 +0'1 St'6 ainqeiadwa y, asury ‘as asRIaAYy ‘aes asvIaAY 001 BLL’ Cl durjuey = 6p] ‘adeyuaosad |pes9AO (ORI ‘Apeag) pynouns9 asaysdooskiyd 0-0 0 0 0 0 [edo 97S-6'L OST 9°SZ 8h 7 80'S pow 1°96-S°LP PLP SPL (amas LY pues 6 1I-e'0 [DAS oP 8e'e ote aquoydsoyd 01-0 S6'E LUE P88 boll syuoone|p b 06S EE 10% L'09 68 ET TPh'SS ford Cae I 10° te'l £9'f al 8S PE-O8'8T ELT pete SESE PL Ol 8th LOTTE OPNNE'T] OOE-O7T 97 TS S ‘col 6087 ptr yideq 8°9-E'T (A564 She t PTE JOVW OLUVIO Vr9°% Le'0 89'€ £9'0 6L't UABAXO PAALOSSIC BL PL-9' bE 90°0 89' bE oPeor re £10 Ope AUTRES CTI-S*L So'l 816 r0'Z 87 ainuiadueay, odury ‘as aavioay ‘a's advioay OOT TIV €] ‘duryuey Z| sadeyueosad |pes9aM (698) ‘Aprag) seplomaqojaud DPAMOYALUAH ANNALS OF THE SOUTH AFRICAN MUSEUM 438 0-0 9CS6L L8-6 8E 89°80 01-100 676 EI L St 8S bt -76 61 S6c TET 8941 I'v-L0 BOSE 9 bE 6r ZIT L adury pt :surjuey gE" :adejuaosed |[eI9AG, 0 81°07 cL Te 9c'l 6 IL Ste 61°67 961 CSE LOE SL be 916 asvloAy 0-0 Iv 6L 1°96°6°8S 6 Ile 0 orl £686 LE LS 8S PE-€9 67 00¢-08 Coe rst 69 PE-19 PE OSL odury ZZ Buryuey =p‘) :aBBJUDOIAd [[eIIAQ. 87 SEO bE 6 ZI-TL asury OZ :Burjuey = Gp :adejUaosad [[e12AG, OOT 001 advloAy 0 66°07 99°CL CLE 8L'1 7S L9 £9'€ £0°0€ 181 Ste See tL be St'6 IBPIIAY 00 0 0 edo 00 0 0 00 0 0 tedo ¥'39°6'L £L SI OL Te paw CMI Ce 8's 18 [iSGalnG LORE 171 pay L89'TE 16ST 6L°S9 pues 6 S698 SLY 716 6S669L SOL S°L8 pues LOIS‘ 0 WES CCE ayuoydsoyd 6TTT 9r'0 Le'l 619°0 vs'0 Cl ajuoydsoyd 01-0 £0°@ CT aytuoone[p) 0 LS'0 L9°0 10 Sr'0 80 9ytUOoNe|L) 6 76ET'L L961 6°89 foor 6 76S 91 Tl 6E £8°6P 676OS'9l IB Te 9P'09 foro Saf £01 LUE ed Lt €L'I S LES ILI ¢ ed t1SeOl6l IS ¢ SL’LT opnyneT GAG RIGS GN BL LL've-Th 87 ETT £8°7e apnyney StL I€l 6 trl £87 widaq SOT SI L°89 SII OL tp 961 LU yidoq LyY'l £8°1 ty Joye! o1ue31Q STTLO 9°0 Ly'l 8-$°0 a 66° Joye o1uediQ VrL'0 £0'1 ZO'€ ——-uaSAXO paarossiq Ure z€'0 €L'€ V'esp'0 OTT £9'% —_- uadAxo paayossiq 8c Seth pe =—LT 0 IL be Ayrurpes vO'SE9' PE v10 69' PE PUSE IS be 610 6L bt Ayres 6r'7I-TI'S Ic] 9°8 aunjesodwa |, OCITVL y9'l L1'6 Selo 9L'I 9S'6 ainyesodwia J, aduey ‘as dPIOAY asury ‘as adPIOAY oduey ‘as adelIAY TIV OOT TIV €66] ‘A[suIq DIsnuaA DUYjanssuOIUT €Z :duryuey = p09) :adeJUaOIAd [RIAA £66] ‘o[3uIq vsodns DjLNDOAISny 00 0 0 redo, 0-0 0 0 0-0 0 0 tedo Ill L901 68°07 pnw Iv-7 SI 186 6 b~ L6vos I'St i) 4 Paw 1°96°6'8S I St 6L pues 88'P8-6 8S L8'6 bO'SL 1966 re 6t'6l £69 pues vrleo 9S't ess ayuoydsoyd Galilalal Ly oC'P py pl-¢0 iy? Sot ayuoydsoud 6L71 ST be 69°81 aytuoone| ST 95 ve 99100 ~~ ek 02 tL‘Ol ayuoone[ €°68°6°L 867 top fooR) TES €E 9¢ 77 vl’? TIlE 8 Pl be Sz £709 foor) [EAS LET Ie'p ed Lae ol 69'P LC 6S" 1 8P'P cs | C6 Pe t9'6C = TOT 68°7E opnyney BS PE CH BT = BUT or % LOPE 6 1e SLE 4 opmyne’y Ip6Sl 1874 L87 yidaq OOE-ST y'18 TSI OS8-tb FIZ 6L7 yidoq eoe'l vl tS? Joye o1ued1O tov"! 18'T 97'E I'el-81'0 L@ SI'¢ Jaye o1URdIO Lys 970 78'E uashxo paalossiq Vyv'e 7'0 OL't BrsrO trl t9°7 uad XO paalossiq] OT SE Ch PE =—87 0 18 be Ayuryes CL PEO PE S0'0 99°PE 9USe- Uh PE 870 18 Pe Ayiurpes Stloe’ 66° 876 ainyesadwia |, OrGale! 6L°0 LL’8 Sel6t 667 876 aunyesad wa |, oduey as aselIAy oduey as adPIDAY odury ‘as adPIOAY TIV OO l1V €66] ‘a1surq Mayjnf DIdao]D4ISNy IZ :Burjuey =p) :adeyudosad [[PI9AG, 0661 ‘SYOoppeY] YPUaniaw "Ww ‘jo SuUdkoOAID! 0-0 0 0 [edo 00 0 0 0-0 0 0 [edo p'89°6°L 98°91 SI te pnw Vre6el 98 6112 CCL = Cli6 7817 pnw L8-9'lt 8°91 SS'S9 pues 9°169°09 916 LS'°8L V96¢LS 2 OI tS'9L pues Vil-¢0 (G6 6P'¢ ayuoydsoyd 6 1I-¢'0 te It'y 6 Tl-t'0 67 It'p ayuoydsoud c70 IS'p 86'1 ayuoone|y 01-0 8 E 9P'? 8£-0 9L'01 L9°9 aytuoone| POEs tt 9C'LI +6 >9 eye) T16-$ 91 x6 tpy'89 T16E7SI 6S HZ L9°S9 "OoRD cl 90°1 ve ed ct 980 bre cl b0'! £e'' a tlSe-t66l = tPF S8°87 apnyyey LS'pe-IP 8% S07 18°0¢ LL'be-St%% LIT L8°0£ apnyney pos ltl £9CT 1L@ widaq 00-071 psp p07 OS8-7P vz 6L7 yidaq 16ot'0 80°7 60°F Joneu s1uediO Cruel Stl 987 9'pI-80'1 [ge cP Jayyeut s1URdIO aa) 96'0 Ile uadkxo paalossiq] I'7 8°72 L¢'0 89't lyspo vil 9L'@ uadhxo paalossic 87 Seth bt = OO IL be Aywurres cs reo re LOO Lye ese Ip pe 70 SL bt Ayures (0) Ar a OS So) | £9°8 aunqesadwa |, OI-I'L £L'0 9L'8 pIEI6E HET L6'8 ainjesadwia }, oduey as aaelaay osury ‘as adeloAy aduey ‘as adelaay TIV 001 TIV €661 ‘sug Mapoym uosaidosayiKD 6] ‘surjuey GQ :adejuaddad [[R19AD 6861 ‘afduiq a AapeyrA snsdound snonupuopiasod 439 QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA VLVd LNAIOIANSNI aguey ‘as 001 aseloAy O€ :Buryuey ZL] :adejuaosad [pe1aaAQ VLVd LNAIIANSNI odury ‘as O01 adeloAy 87 ‘durjueYy = 6 | 0 :adejuaoI0d [[eIZAGQ 10°00 SOI-s'9 06-192 8°0S-S'0 10°00 Ces LL VT tr eZ tr 02 007 ObT DEES 609°0 SI S€-66' Fe COET-IL TT asuey +00'0 S8iT gs‘9 80°61 +00'0 TE BT 780 STI C81 SIT c1‘0 90°0 cs0 ‘as TIV c00'0 S78 LL°78 cIOl 800°0 Be 19 £e°7 86 17 CO cys 8L'0 60°St Ly7l aseloAy 7661 ‘a[3uIq vISsNgos sisuanuskuy DIUOSUag 00 8 est Ol 196-794 ¢¢c9'0 8£0 T'98-L°€7 cl SL'VE-6 77 Sve 981 L997 I SV? SL PL 6 PE oe adury 0 611 C8°CI 781 8h Se'sI orl Ive 9ET Ly'l 8L°0 ITO 89°T ‘as TIV or a AS Shee ACSontuo iol 3 \o asPloAy 066] ‘19WOOg 2 pioT ‘a]duIq Ipjafiuaso4s DINOJUNg 0-0 0 9tS-6'L L791 916S'Lp SB ST LS€0 66'1 O-l BI'e £°68°S Cf Lv vt Ge 860 BS PE-Ch Bt SST 077071 BSCE 89°C I (4 6BOCE 610 BLO PE 90'°0 O1-S'8 eS'0, odury ‘as OO 9¢ ‘duryuey rN aAmaataNnanyryToO Ka 4 ZO ‘admuaosad |pe19AG 0-0 6 SL-6'L 196-1’ Pe y9-¢'0 97-0 £68°L'E1 ol BL PE-LS LI 006-071 tLe l BS B Poy PE O18'e aduryy ‘as TIV 0 66° SE 6'£9 LUT 66°L £0°09 BL 860 6¢P LS'¢ BE 6S PE PL ddRIOAY €661 ‘Alsurq Mauwasq viuojung GZ Buryury 9 ¢'Q ‘adejUadsed [[R19AO edo 00 0 0 00 pny 97S6L v8°LI 8S LT LO6L pues 916-6 8E S06! See9 916-6 8E ayoydsoyd 61-0 (Aa) £0'T 690 ues) 1-100 br 0 7L'0 +1-0 (0}0)8) EESEEEIGL EGC bl tr LSLEVl oF Lt 6c 1 SLD Le opnyney 8S re 661 = 709 80'TE L6'PL-76 61 yideq S67 S6 S79 Sol 06$-S6 Joyeul o1ued1Q Soe T Bie SLY £81 uadhxo paarossiq 6€L'0 Gl 60°€ 10 Ayrurres BT SE-19 bE =~ O SL PE 87 SE-LP PE ainqesedwia 6P 71-8 tase! $9°6 or 7I-S's osuey ‘as aseIOAW asury 001 67 :suryuey = 6]. ‘0 :adeJUOIAd [TeIAAG redo 00 0 0 0-0 pny 9CS6L VLI 6 £7 9S 6L pues P'98°6 8E IZ a) Py 98-6'8E ajuoydsoyd 6180 cr'0 971 69°S°0 ouusenel®) 1-100 br'0 80 71-100 ODRD 6 76S EE 6L°97 97°89 6 76S Ef ad LEE vl tL't LI apniney TS PEO 6I = BEF IL Te cS PE OT 61 yidaq L7Z-08 tly Sel £SP-08 Joyew o1uediQ 8 OFT 80°7 8P't o+'I uaskxo paalossiq Tt-L'0 660 See I'+-L°0 Ayuryes 8USE-9' PE c0 PL PE BU SE-Th PE ainjesedwiay, 6P TI-S'8 IV Ip'6 6P ZI-ZI'S oduey “aS aaelaay adury OOT LZ sdurjuey—s- | ¢ 9 ‘adejuaosad ]ye19aAG tedo 0-0 0 0 0-0 Paw 9°CS-L SZ 7061 SI 6£ JTS-L'Se pues pL-S°Lp PL'8I SL°09 PLU ip ayuoydsoyd 11-80 170 S60 11-80 aytuoone|f) II 0 I i foor) SOR S te 16 OF LSS te ad [EAS Vl gs Ls apnyney IS Pe-96' EE £70 IT be L6'PE-96 EE yidoq OP1-08 LO'S@ £1 OFI-08 Jaye o1uediO 89° LZ 6s BOS b uadkxo paajossiq LE-SS'E 170 99°¢ [Boas Ayres SL'be-19' be = 90°0 LOPE CO PE19 bE aunqesaduna J, COS’ tro a) OT ZI-S'8 odury ‘as aswoay adury OOT SHASuHASSoAMNS a ae bs bal oe =SAMAIND+HO— + SS DAYS wo = A n TIV ~ on AANNCOTOPM GZ-SSH—mSH-AHoCS a -anbost mi (a z 0 pS°7E 9P°C9 pe'% 781 LOIS 6t'P St 87 LIT 10'S CLT IL’be 98°8 aseloAy edo pny pues ajuoydsoyg aytuoone[H zeye)8) ad apniney yidaq Ja}W D1uUeZIO uasAxo paajossiq Ayres ainjeiadwia y, €661 ‘asurq iws4va8o41 Diuojung redo, Pay pues ayuoydsoyg aytuooneryH foorD bast apne yidaq Jae sTUPsIO, uasAxo paajossiq AUS aunyesadwiay, C661 ‘A[surq wnsopouty uosaidosayiKD advVioAy redo pow pues aquoydsoyg ayuooney 5 toorod od apnyary wdaq JANVUL NuURIIO. uadAXO paalossiq AUTRES aunqwradwa y, £661 ‘Asura syourg vquanboy ANNALS OF THE SOUTH AFRICAN MUSEUM 440 0-0 OTSL ST bL-S'Ly 11-80 I-I COPS te os CS PEPE OrI-02I 89S LESoe OL bE -19 VE Voss odury 0 0 c0'61 ST 6 Pls SL°09 170 S60 0 I 616 Or 0 Ss 870 (a3 Ol 0c! 8c 6s £0°0 89'€ 180°0 LOE cs0 16 ‘as adelOAY 00! gg :Burjuey = €0'0 :adejuaosad [[e1aAC 0-0 LST-L’S7 bL-bL Talay Il SEES EL LS 60' Pe -Fe O9T-ST cS SLO’ SO PEO PE v'6os'8 asury 0 0 0 L'S@ 0 bl 0 Vl 0 I 0 cee SIT L9°S S0°0 SO're 8S°8L Sol 0 ¢ 80'0 LOIS £00 t9°pe Sr'0 68 ‘as adelaAVy OOT pe idurjuey 900 :adeyuaosed ]]eR19AQ, 87 SE-89 He 6b 71-168 asury Ze :sunjuey 0 0 -9°TZI CI? 9¢ 6] L8°8S VT £0°¢ Gia pe"? 88°C VTL 850 te 80°9 b6°97 $9°09 £17 LO'T LL'¢ 81 LL'Z te'0 68°PL 10° LI01 ‘as aBRlIAy 001 G10 :adequaoiad [[e19AQ 0-0 0 0 ted 0-0 9° CS-L SZ 7061 SI 6£ pny LS-6'81 6e°eI zee eee tL SLY vl 81 SL’‘09 pues CS 6L-Eb C8 rl 9€°19 pues 11-80 170 $60 ayuoydsoyd 829°0 88°7 Ise ajuoydsoyg Val 0 I ae one 9r-0 LLLI 61 ZI a}luoone|[H SOS CE 61°6 Ov (0/0) 0) TS8-@'ST 8°SZ 60°€9 ioye)70) gs 0 s 9d ol L9'T Te ed CS PEE 870 TPE apnyney LL YEH ET B7E £9°0£ apne] OvI-07I Or O€l yidaq VLVd LNAIDISANSNI 006-Z6E 991 76S yidaq 89° 871 6's Jaye o1ued1Q, SoET So’ £ Joyew o1urediCQ, Le-so'e £0°0 89'€ uadhxo padlossiq Livalac 700 vo’ uasXxo paajossiq OL'VE-19' PE 180°0 LOPE Ayuryes ID’ per be 60'0 6r Pe Aiuryes vos 3 (40) 16 ainjeiodwia |, VL-8°€ CO’! €8°S ainjesodwiay, oduey ‘as aseloaAy adury ‘as adeloAYy oduey as aseloAy TIV O01 TIV €661 ‘e[8ulq vamap viuojung Ce ‘Bunjuey—- p)'. :adeJUDOIAd |[[eI9AG 066] ‘19WOOg 2 ploy ‘a[BuUIG sLDynIDds ayIUy 0-0 0 0 redo 0-0 0 0 10°0 €00°0 — 8000°0 redo LSv 681 8'P £7 pnw Pp Orel £701 £7 SSreL v6'€l OPT pnw L°8LbL tee SOL pues 06-769 16 8°9OL 06-F' SS (ama Be EL pues BL LIT tly Sry ayoydsoyd tr 60 a | v'T SCS 0 Srl PP ayuoydsoyg (Gomi 7617 SOI Soest) 100 c'0 8S°0 1-0 6r'0 tr'0 a}uooNe|H SeeT SI 7671 SEPT (0/0) 8) LBL EVl tC Pe 8P'8P Tse Il 0¢ £9°0S foor) LS I'l 8S od Sw IZ] 98'£ Lt 79" 8S'¢ a LL bE" ve 70 THE apnyney 60'Pe th 0% 69'S 66°87 60' PEP Oe LIS £S°L7 opnyney SpS-SI £17 O8T yidaq S67 0721 9S'9¢ £81 6Lt-001 80°92 £61 yidaq Srl SoZ GE Jaye sued iQ, 6 SHE -0'l tr'p 8 8-P7'E c6'l 88°S Joyew o1urdi¢Q LYOet Ly0 L8°¢ ua3Axo padossiq SLL 0 SIT 18'Z CLiteLi0® "iCal Let uadhxO paajossiq] S9'PL-9 PE £0'0 £9' Pe Ayres 66 PEO bE Am) IL pe cO'Se-S'pe LI'O SL be vols +9'0 818 ainjesadua {, 9L7I-8 9c°1 v'6 9L7I-S'9 BLT 796 aunyesaduua J, asuey Yatay ddPIIAY osuey as aseioay aduey “a's asRloAy TIV OO! TIV 7661 ‘2[SuIG MUDDY Stuagajolsax €€ ‘duryuey =|. °Q :adeyuaosed [pe19AG, €661 ‘a/duIq Ip4o] Salipnoz0aN 0-0 0 0 redo 0-0 0 0 0-0 0 0 jedo £89°L'9 £S'9] L8°0€ pnw I pel Tl 60°L €S°@ Ipe-L'@1 = 89 81'€z pnw 1°96-6'8t 9S°LI 8°S9 pues L8-L°S9 GL €e°LL L8-L'S9 eZ eL’SL pues 4980 66'1 6b'c ayuoydsoyd 89 Pb 101 cs 89°F 80°2 8r'P ayuoydsoyd 95-0 cl8I S8°TI sy uconelo) 0) 91% L9'} 9-0 £0°7 CI'Z ayiuoone[H T88-6'P 89°97 9°8¢ (0)e) 2) POET IL (a/b C78 POETIL S69 60°18 Foor) cl OI of ed CaG 0 £ G4 S70 767 a4 cLpe-t6'6l = LOY (aus opnyyey CS'OL-7h'8Z = 6L'0 tr’ 67 Ie 1e-Cp'8% P01 8°67 apmney 06S-0S1 Or 98t yidaq IL7-OLI 7O'8E LOZ cLe-OLI 87 Or LIZ yidaq 69°60 Sri Ole Jaye s1ued1Q tr? 60 96°7 Cr $8'0 L67 Jaye o1ued1C, Srl 0 96'0 89°¢ uadkxo pealossiq Lams Sr coe ¥8°7 tr'0 BS'¢ uadhxO paalossiq 87 Stok PE 70 COPE Ayruryes SB Pe-9O' PE 60°0 IL'Pe S8 Pe 9 PE 780°0 Lv’ Ayrurpes 6P 7I-ZI'S 6L'I COL aunjesadwia L CrGalgl ¥8°0 £L'8 COL o8'0 9°8 aunjesaduia |, osuey ‘as asvloAy osuey as ddPIOAY oduey ‘as adeIIAY TIV OO TIV €661 ‘a[surq sisuapnbouou viuojung I€ ‘sunjuey 9] ‘9 :adejuaosad [ye19AQ, £661 ‘9/duIq] p4aqgqia viuojung 441 QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA “y, = jedo ‘pnw ‘pues ‘ayoydsoyd ‘auooneys ‘fQoe9 ‘at $s, = apminey Sw = yidep f% = sew d1uRdso ‘|/Ju = uadAxo paajossip ‘puesnoy) sod sued = Ajuryes {9g = ounqesaduiay :sMopoJ sv passardxa av aAoge UDAIS SJo}aUeINd aY]—I)ON 88-0 IZ TE 60 6l edo 1'66°L'0 6£ 87 tELD pnw 186-40 6S°LZ ce'0S pues Vsi-c0 LOY lee ayoydsoud 69-0 Srel tp 8 O0L-1'0 [HEM L’st STITI9O 767 Lo'’ 60 PE-LS'LI th'b 8° Pe 066781 £07 (o.41 yidaq L'00-7'0 6'P goo Joye s1URdIC, Vr6e70 i'l OP | SIC Sse-ot be §=1t0 St Lutes ple She 7801 aunjesodwa yf, adury ‘a's advioay (Og = U) sajduues Udsegy 6. SYSTEMATIC papers must conform to the /nternational code of zoological nomenclature (particu- larly Articles 22 and 51). Names of new taxa, combinations, synonyms, etc., when used for the first time, must be followed by the appropriate Latin (not English) abbreviation, e.g. gen. nov., sp. nov., comb. nov., syn. nov., ete. An author’s name when cited must follow the name of the taxon without intervening punctuation and not be abbreviated; if the year is added, a comma must separate author’s name and year. The author’s name (and date, if cited) must be placed in parentheses if a species or subspecies is trans- ferred from its original genus. The name of a subsequent user of a scientific name must be separated from the scientific name by a colon. Synonymy arrangement should be according to chronology of names, i.e. all published scientific names by which the species previously has been designated are listed in chronological order, with all references to that name following in chronological order, e.g.: Family Nuculanidae Nuculana (Lembulus) bicuspidata (Gould, 1845) Figs 14-15A Nucula (Leda) bicuspidata Gould, 1845: 37. Leda plicifera A. Adams, 1856: 50. Laeda bicuspidata Hanley, 1859: 118, pl. 228 (fig. 73). Sowerby, 1871: pl. 2 (fig. 8a—b). Nucula largillierti Philippi, 1861: 87. Leda bicuspidata: Nicklés, 1950: 163, fig. 301; 1955: 110. Barnard, 1964: 234, figs 8-9. Note punctuation in the above example: comma separates author’s name and year semicolon separates more than one reference by the same author full stop separates references by different authors figures of plates are enclosed in parentheses to distinguish them from text-figures dash, not comma, separates consecutive numbers. Synonymy arrangement according to chronology of bibliographic references, whereby the year is placed in front of each entry, and the synonym repeated in full for each entry, is not acceptable. In describing new species, one specimen must be designated as the holotype; other specimens mentioned in the original description are to be designated paratypes; additional material not regarded as paratypes should be listed separately. The complete data (registration number, depository, descrip- tion of specimen, locality, collector, date) of the holotype and paratypes must be recorded, e.g.: Holotype =a SAM-—A13535 in the South African Museum, Cape Town. Adult female from mid-tide region, King’s Beach, Port Eliza- beth (33°51’S 25°39’E), collected by A. Smith, 15 January 1973. Note standard form of writing South African Museum registration numbers and date. 7. SPECIAL HOUSE RULES Capital initial letters (a) The Figures, Maps and Tables of the paper when referred to in the text e.g... . the Figure depicting C. namacolus ...’: ‘. . . in C. namacolus (Fig. 10)... .’ (b) The prefixes of prefixed surnames in all languages, when used in the text, if not preceded by initials or full names e.g. DuToit but A.L.du Toit; Von Huene but F. von Huene (c) Scientific names, but not their vernacular derivatives e.g. Therocephalia, but therocephalian Punctuation should be loose, omitting all not strictly necessary Reference to the author should preferably be expressed in the third person Roman numerals should be converted to arabic, except when forming part of the title of a book or article, such as ‘Revision of the Crustacea. Part VIII. The Amphipoda.’ Specific name must not stand alone, but be preceded by the generic name or its abbreviation to initial capital letter, provided the same generic name is used consecutively. The generic name should not be abbreviated at the beginning of a sentence or paragraph. Name of new genus or species is not to be included in the title; it should be included in the abstract, counter to Recommendation 23 of the Code, to meet the requirements of Biological Abstracts. SMITHSONIAN INSTITUTION LIBRARIES \ “WEN 3 9088 01206 7088 R. V. DINGLE QUATERNARY OSTRACODS FROM THE CONTINENTAL MARGIN OFF SOUTH-WESTERN AFRICA. PART III. OCEANOGRAPHICAL AND SEDIMENTARY ENVIRONMENTS