ABSTRACT The distribution and taxonomy of modern benthic foraminifera are described for the western Sunda Shelf, southern South China Sea off northeast peninsular Malaysia. This study provides baseline foraminiferal data that can be utilized in paleoenvironmental reconstructions of Neogene sediments from the Sunda Shelf and elsewhere in the Indo-Pacific. The uppermost centimeter of 60 surface sediment samples (> 150 µm) from nearshore (8 m) to inner shelf (60 m) water depths yielded 125 species. The distribution of these species is described and 120 species are illustrated with color light microscope digital images and scanning electron microscope imagery. Five sample assemblages, CGT1-CGT5 are interpreted from the results of the cluster analysis of total (live plus dead) foraminiferal relative abundance data. Discriminant analysis demonstrates that these five groups are statistically distinguishable at the 95% confidence level. The distribution of groups is related to variations in depth and substrate grain-size. This relationship is reaffirmed by canonical correspondence analysis. Closest to shore (8–14 m water depth), the high diversity (49 species) assemblage (CGT1), characterized by Amphistegina radiata and Amphistegina lessonii , occurs in medium to coarse quartz sand substrates, likely derived from the nearby Terengganu River. In slightly deeper water (21–22 m) and in gravelly quartz sand substrates, the lower diversity (33 species) assemblage of CGT2 is strongly dominated by Amphistegina radiata and Amphistegina lessonii . CGT3 occurs in shelly muddy quartz sand substrates (32–41 m), has a high diversity assemblage (46 species), and is characterized by Assilina ammonoides , Amphistegina radiata and Discorbinella bertheloti . Berthierine internal molds of Amphistegina lessonii and Amphistegina radiata are common in CGT1, CGT2 and CGT3, possibly indicating reworking from Pleistocene deposits in the region. High diversity (51 species) assemblage CGT4 occurs in mud substrates (44–59 m) and is characterized by Heterolepa dutemplei and Asterorotalia milletti ; the nearshore, sandy substrate taxa Amphistegina radiata and Amphistegina lessonii are absent. CGT5, located farthest from shore at 60 m water depth and in shelly sandy mud and shelly muddy sand, has a high diversity assemblage (46 species) characterized by Heterolepa dutemplei and Assilina ammonoides , with rare Asterorotalia milletti . This assemblage may be, in part, a lag deposit associated with modern bottom currents. The results of this study were combined with previously published research to identify nine foraminifera-based environmental subdivisions in the southern South China Sea: mangrove swamps in Terengganu and Sabah, Malaysia; high salinity lagoonal and inlet assemblages in Terengganu, Malaysia; low salinity estuarine assemblages in Terengganu, Malaysia; Mekong Delta assemblages; nearshore areas in the northern Gulf of Thailand off the mouths of rivers; inner shelf environments off the Mekong delta and off Johore, Malaysia dominated by Asterorotalia pulchella ; shallow inner shelf (<40 m water depth) environments from Terengganu and Johore, Malaysia; inner shelf environments (40–100 m water depth) off Terengganu, Malaysia and on the east-central Sunda Shelf; outer shelf environments (100–200 m water depth) on the east-central Sunda Shelf. The subdivisions are related mainly to salinity in marginal marine environments and substrate type and depth/distance from shore in shelf environments.

ABSTRACT Foraminifera were examined from the top centimeter of 378 gravity core bottom samples (with samples from a few additional depths in some of the cores), and bottom grab and dredge samples. The samples were collected from numerous traverses made in the Timor Sea in 1960 and 1961, from Australia across the Sahul Shelf and Timor Trough to Timor and the adjacent islands of Roti and Leti, and from depths of 20 to nearly 3,500 meters. A total of 946 species are described and illustrated, representing 127 foraminiferal families (two new), 118 subfamilies, 428 genera (12 new), and 944 species (101 new). In addition, two new genera and species of incertae sedis are described. New taxa are the agglutinated Placopsilina bifurca, Barbourinella teretis, Liebusella improcera, Textulariella parvacycla, Karreriella pseudowrighti, Bigenerina aspratilis, Plotnikovina timorea , the porcelaneous Glomulina rotiensis, Nubeculinita ramosa, Spirophthalmidium prolixum, S. scabrum, Kalosha aluta , new genus Mikrobelodontos , type Spiroloculina bradyi Barker, Spiroloculina abatholopa, Ammomassilina clypeoarenula , new genus Falsagglutinella , type F. byrsa, F. angularis, Pseudoflintina laculata, Massilina timorensis, Quinqueloculina adiazeta, Q. ectypha, Q. latidentella, Q. vandiemeniensis, Miliolinella heligmateira, M. obstipacella, M. quinquangula, Triloculina triquetrella, Triloculinella chiastocytis, T. parisa, Sigmoilopsis revetocollaris , new genus Euthymonacha , type Monalysidium politum Chapman, E. leura , the Lagenida Dentalina ruidarostrata, D. semiinornata, Enantiodentalina timorensis, Grigelis orectus, Nodosaria timorensis, Saracenaria stolidota, Siphomarginula angulosa, Spincterules compressus, Amphicoryna leurodeira, A. meringella, Astacolus paucacostatus, Marginulina paeminosa, Vaginulinopsis gnamptina, Cerebrina serangodella, Conolagena polystroterina, Lagena annellatrachia, L. kermatoina, Pygmaeoseistron annulatacollare, P. cyrillion, P. treptoinum, Reussoolina stellula, R. strangeri, R. trachiella, Globulina acocebathra, Sigmomorphina beaglensis, Ramulina angusta, R. confossa, R. vanandeli, Exsculptina glaphyraheda, E. athyrmata, Favulina colubrosacosta, Galwayella trixopteryx, Oolina baukalionilla, O. kleithria, O.parisoina, O. stiktosa, Duplella trinalimarginata, Fissurina deuterolegna, F. infimabrocha, Lagenosolenia duplicimarginata, L. laciniosa, L. peltatusella, L. physamorphina, L. strigimarginata, Pseudofissurina konara, Nanosylvanella pattersoni, Pytine lemniscata , the Robertinida Saintclairoides toreutus , the planktonic Tenuitella kyrtomina, Globigerinoidesella bollii , and Globoturborotalita decorata , the Buliminida new genus Aphelophragmina , type Textularia variabilis var. spathulata Williamson, new family Cheilochanidae , new genus Cheilochanus , type C. minutus, Heterocassidulina saidovae, Cassidelina sgarrellae, Loxostomina costatapertusa, Rectobolivina akainophera , new genus Alassoida , type Sagrina virgula Brady, Bulimina acaenapeza , the Rotaliida new family Neoeponididae, Rosalina cosymbosella, Glabratellina traphera, Siphoninoides diphes , new genus Facetocochlea , type Pulvinulinella pulchra Cushman, new genus Poroepistominella , type P. sahulensis, Pseudoparrella zhengae , new genus Prionotolegna , type P. paeminosa, Planulinoides polymitarius, Discorbinella serangodes , new genus Orbiculoris , type O. tubulorictus, Carpenteria polythylakina , new genus Patagiatella , type Epistomariella milletti Collins, Nonion grossepertusum, Resigia quadrata, Alabamina achanes, Anomalinoides rotiensis , and new genus Cristatavultus , type Elphidium pacificum Collins. The two new genera and species of incertae sedis are Octonoradiolus , type O. polythylakus , and Stictogongylus , type S. vandiemenensis .