key: cord-0010008-19mtebq7 authors: WALLACE, CARDEN C.; WOLSTENHOLME, JACQUELINE title: Revision of the coral genus Acropora (Scleractinia: Astrocoeniina: Acroporidae) in Indonesia date: 2008-06-28 journal: Zool J Linn Soc DOI: 10.1111/j.1096-3642.1998.tb01302.x sha: c4b231e1655ffbb54270d3c72bfbe8a00bbcff16 doc_id: 10008 cord_uid: 19mtebq7 The coral genus Acropora is reviewed from Indonesia for the first time, following detailed collections made at 131 sites and additional material collected from approximately 40 sites throughout the archipelago during the period 1993–6. Eighty‐three species are recorded, four of these (Acropora halmaherae, A. awi, A. plumosa and A. simplex) new to science, six first described in 1994 and six in 1997. Records are compared with specimen‐based records from localities worldwide. The species of Acrokora occurring in Indonesian waters include five recorded only from the Indian Ocean and Indonesia, seven recorded only from the Pacific Ocean, South China Sea and Indonesia, and a further 10 species apparently endemic to Indonesia, as well as widespread Indo‐Pacific species. Two species (A. jacquelineae Wallace, 1994 and A. batunai Wallace, 1996) are recorded only from north central Indonesia and Papua New Guinea, and two species (A. russelli Wallace, 1994 and A. turaki Wallace, 1994) only from north central Indonesia and north western Australia. The findings contribute to a new view of the corals of the Indo‐Pacific ‘centre of diversity’ as a composite fauna with origins in a number of events in space and time. Detailed site data are given in the Appendix and location of collecting sites is indicated in Figure 1 . Between October 1993 and June 1995, 109 sites were sampled in detail by the authors in S. Sumatra, E. Kalimantan, N. Java, Bali, N.W. Lombok, N.M'. Sulasi, Central Sulauesi, S. Sulawesi, Ambon, Banda Sea, N. Flores, Alor Islands and I$'. Timor. A further 22 sites in Central and N. Sulawesi, Halmahera and Bali were sampled in detail in June 1996, but only new species and significant neb records from these sites are included in this revision. Latitude and longitude of each site is accurate to the nearest minute from Admiralty charts. Additional samples were received from: Nias, W. Sumatra (M. Christensen); Riau/Lingga Archipelago, E. Sumatra (J. Thorogood, I. Neuss); Seribu Islands, Ja\,a (LIPI staff. C. \Yilkinson, T. Tomascik Sampling by the authors followed a standard protocol at each site, using Scuba (occasionally snorkelling or reef-walking on shallow sites). Collection and recording of ilcroporu species began from the greatest depth at which they could be located (usually 25-28 m) and then continued upwards to shallow water, over a horizontal distance of 100 to 400 m. Habitat features and dominant benthic groups were noted for each site. For each species encountered, a sample portion of the colony was taken; more colonies re sampled when unusual forms or undescribed species were encountered. hlost specimens were photographed in situ before collection. A tentative identification, colour of the colon)-, and depth at which it occurred, were recorded, along with other relevant features such as unusual size or colony shape. A numbered plastic label was attached to each specimen as it was collected. After the dive, specimens were bleached in household bleach (sodium hypochlorite), rinsed in fresh watrr, and dried. Specimens were returned to the Museum of Tropical Queensland in Australia, where they were re-examined, identified, registered into the specimenbased database (using an RBASE system) labelled and stored in the Museum's permanent collection. Duplicate specimens, representing all species collected, were provided for the Indonesian Institute of Sciences (LIPI), and deposited in: LIPI Research and Development Centre for Oceanology (PPPO) at Ancol, Java (N. and Central Sulawesi collection); LIPI PPPO at Ambon, Moluku Province (Banda Sea collection); and Department of Marine Science, Bung Hatta University Padang, Sumatra (S. Sumatra couection). The full set of sites a\,ailable for species distribution records within Indonesia is given in the Appendix and Figure 1 . For individual species, the range of localities occupied and number of specimens available for study are indicated in 'Material examined' under the species heading. The specimen-based database was used to prepare a distribution list for each species in ASCI format, including site coordinates with each specimen record. These lists were used to plot the distribution records for each species in Indonesia, using a MAPINFO GIS package for WINDOWS. In order to indicate the broad geographic spread of the species outside Indonesia, a small inset map is included with the Indonesian distribution map for each species. This inset map is plotted from records within the specimen-based database, which at the time of preparation included some 15 000 records from some 800 sites worldwide (indicated in Fig. 1 ); in addition to these specimen-based records, the type locality for each species and its synonyms is indicated by a star symbol on the map. A detailed outline of the sites and records worldwide used for the preparation of this inset map will be available in Wallace (in press ). For brevity, specimens examined for this review are cited by registration number and by an abbreviated locality. For each region (e.g. N. Sulawesi) , specimen numbers from within that region are listed, followed by the abbreviated site (e.g. Bunaken N.P. for the islands in the Bunaken National Park). An exception to this is the citation of type specimens of new species: collection data for these specimens are cited in full. A full catalogue of the Indonesian specimens in the Museum of Tropical Queensland is available in hard copy or on disk on request. Geographical terms have been translated into English. An exception is the Indonesian term 'tanjung' (abbreviated as Tg), referring to a cape or point, which is retained. Although genetic and breeding experiments indicate that morphological boundaries may not differentiate fully amongst Acropora species (Wallace & Willis, 1994) , morphological characters combined with field appearance remain, for the present, the only characters available across the full range of species and thus the only indicators of species boundaries. Discriminant function analysis of morphological characters over a subset of species confirmed morphologically-defined species boundaries (Wallace et al., 1991) and reinstated finer species boundaries indicated by breeding experiments between morphs of another species (Willis et al., 1997) . Thus traditional morphological characters are used in the descriptions in this review. For detailed skeletal measurements, three specimens of each species from Indonesia were examined using a Wild M8 microscope with eyepiece graticule, lit by fibreoptic lighting. Measurements and qualitative characters were taken for five branches, five axial corallites and five radial corallites. This information was added to alreadydocumented information for each species (Wallace, 1978 (Wallace, , 1994 (Wallace, , 1997a Veron & Wallace, 1984; Wallace & Dai, 1997 and type descriptions) as well as field notes regarding colony shape and size of all specimens taken, to give the final diagnosis for each species. If the Indonesian specimens diverge from characteristics of a species elsewhere, this is noted in 'Remarks'. For illustration, electron micrographs were taken using the Phillips XL20 or the C C \V.\LIAC;E ANDJ \VOI,STENHOLhlE JEOL scanning electron microscope at James Cook University, Townsville, Australia. Photographs of skeletons were taken by Photography Section, Queensland Museum, Brisbane and by Z. Florian, Townsville. Photographic plates comprise these photographs and field photographs taken in situ mainly by C. Wallace and sometimes by M. AUJ or R. &ello. Field characteristics, including colony shape, colour, habitat distributions and other relevant field information describe the species within Indonesian waters. Any major divergence from these characteristics as recorded elsewhere in the world is noted in 'Remarks'. RESCLI'S .ISU DISCCSSIOS Eighty-three species are recorded in this study. Because of it3 complex tectonic histo?, active geology, multiplicity of coastlines, hydrological characteristics and depth contours, the Indonesian archipelago has a great varietj of antecedent structures and reef types. In most regions, several different kinds of reefs are found in close proximit).. Because of adjacent islands and reefs, strong currents occur in many locations (up to 5 knots encountered in this survey). Depth of water immediately offshore from reefs varies from around l 0 0 m on continental shelf reefs (e.g. in the Java Sea and Spumonde Archipelago) to around 2000 m (e.g. in the Banda Sea reefs), as can be seen from charts of the region. Temperatures encountered liere usually in the range 27 30"C, but much lower temperatures were occasionallp encountered in areas of upwelling (e.g. 16°C at 10 m depth at site 69, Alor Islands) or in waters apparently affected by high algal content and/or long-term cloud cover (e.g. 24°C at 10 m on reefs off Padang, W. Sumatra). Higher temperatures (up to 32°C at 10m) were encountered in the vicinity of volcanic activity (e.g. in parts of Gunung Api reef, Banda islands) or on shallow volcanic ash slopes (e.g. Tulumben wreck, E. Bali). The following is our summar)-of reef types encountered in the survey: these reef types are allocated to the sampling site? in the Appendix: basaltic flow slopes belohv recent olcanoes volcanic rock slopes volcanic ash slopes rocky slopes fringing reefs dense coral slopes sandy slopes vertical walls and associated reef flats rubble banks underwater volcanoes reefs with emergent tops submerged reefs atoll reefs sheltered inlets and lagoons v ithin reefs cay-bearing reefs on continental shclves The dominant benthic organism encountered at each site is also recorded in the Appendix. While an Acropora assemblage is sometimes a dominant feature of Indonesian reefs (e.g. on many submerged reefs and gentle sandy slopes), this is not always the case. In particular vertical walls (a very common reef type) are not dominated by Acropora, although the species number may be high. In general reef flats associated with vertical walls and fringing reefs are narrow in Indonesia and do not have large assemblages of Acropora. The species composition of Indonesian Acropora includes 1 0 species (Acropora sukarnoi, A. derawanensis, A. halmaherae sp. nov., A. indonesia, A. awi sp. nov., A. desalwii, A. suharsonoi, A. simplex sp. nov., A. plumosa sp. nov. and A. togianensis) which are to date recorded as endemic to Indonesia. Ranges of the species A.jacguelineae (type locality E. New Guinea) and A. russelli and A. turaki (type locality W. Australia) are extended into Indonesia. Five species (A. turaki, A. indiana, A. rudis, A. russelli and A. kosurini) are recorded from the Indian Ocean as well as Indonesia, but not from the Pacific Ocean. Seven species (A. cuneata, A. cratemformis, A. jacquelineae, A. batunai, A. sarmentosa, A. nana, A. speciosa) are recorded on the database from the Pacific Ocean (and sometimes also South China Sea and Philippines) as well as Indonesia, but not from the Indian Ocean. Of the remaining 61 species, most have widespread Indo-Pacific distribution, although a few (A. solitaryensis, A. bruegemanni, A. glauca and A. abrolhosensis) are limited to the central Indo-Pacific. Thus the 83 species recorded in this revision are not distributed evenly throughout the archipelago; nor do they occur concentrically in a pattern that could be considered to indicate a 'centre of origin' (Stehli & Wells, 1971) . Although the species composition is dominated by wide-ranging Indo-Pacific species, a dual pattern is discernible, in which Indian Ocean and Pacific Ocean distributions overlap into the south-western and northeastern parts of the archipelago respectively. While the ranges of species apparently endemic to Indonesia probably will be extended outside the archipelago, some species distributions are clearly restricted regionally, e.g.: Acropora suharsonoi and A. sukarnoi to the island chains of Nusa Tenggara and Sumatra-Java; A. desalwii to the Banda Sea and neighbouring waters, A. halmaherae to the Molucca Sea and A. derawanensis to the Celebes Sea. Most distinctive amongst the localities sampled in Indonesia was the Togian Islands, lying within the waters of the Bay of Tomini in central Sulawesi. Umbgrove (1940) noted that these islands are protected from prevailing winds and occupy a position between two major monsoonal influences; he did not, however, record any unusual species, probably because his investigation was limited to shallow water. Our studies of only 13 sites within these islands (see Appendix) revealed a composite fauna comprising endemic species, rare species (such as A. caroliniana and A. multiacuta), and the species mentioned above with disjunct distributions. Most unusually, all of these species occur abundantly, making this the most unusual Acropora fauna we have ever seen. A 'Tethyan-relictual' origin was proposed to explain the unusual coral assemblages of these islands (Wallace, 1997b) . The hypothesis is that contained within the fauna of the islands is a relictual element of the earler coral fauna of the Tethys Sea, which was gradually closed by movement and docking of terranes from its borders during the Miocene period. The three major patterns of distribution of drropora species discussed above are identified by \$'allace (1 997b) as: 'duality', 'endemicity' and 'Tethyan-relictual', and it is concluded that the Acropora species composition of Indonesia is a composite with origins in a number of events in space and time. The genus Acropora has the characters of the family Acroporidae (synapticulotheca, simple septa and no columella or dissepiments) and is defined by its mode of growth, in which a central or a&/ corallite extends and buds off subsidiary or radial corallites iOken. 1815; \Yells. 1936; IVallace, 1978) . Growth form. The mode of growth leads to a variety of growth form options, so that characteristic growth forms of species are often difficult to define clearly. The colony shape definitions used in the species descriptions describe the usual shape of the colonies in the field (see Fig. 2 ). Avial corallites. Axial corallite diameter is expressed as the range for outer diameter and inner (calice) diameter. In general, minimum diameters for Indonesian species are less than those previously recorded for the species. Radial corallites. The shape of radial corallites provides a major defining character for .Icropora species and species groups. Several terms are used to describe the main a ?? shapes seen and these are illustrated in Figure 3 . The descriptions of the radial corallites for each species include an indication of whether the radial corallites are all of similar size and/or shape and whether or not the radial corallites are crowded on the branches. These conditions, while showing some overlap, are relevant to the definition of species groups. Septal measurements. Septal details are included for completeness of description, but do not constitute the major distinguishing characters for the species. For both axial and radial corallites the maximum extent of septa into the centre of the corallite (expressed as a proportion of R, the radius) is indicated. In general, septal development is less in Indonesian species than for the species occurring elsewhere, so that specimens encountered are likely to have less than the maximum septal extent. Coenosteum. In usual coral terminology, 'coenosteum' refers to the skeletal material between the corallites. Because of the budding mode of Acropora, where a central axial corallite extends and buds off radial corallites from its sides, the material between the radial corallites is also the wall of the axial corallite. The entire skeleton of an Acmpora colony (other than the epitheca) can be said to be formed by synapticular development, with infilling (Wells, 1956; .Wallace, 1978; Gladfelter, '08 C C . \VALLKE . W D J. iVOLSTENHOLME a b C Fi\gure 4. Some coeno~teum 5Tes used in text. a: costate: b: costate on radial corallites, reticulate between; c: costate or lines of simple spinules: d: reticulate. e: reticulate with simple spinules; f: evenly distributed spinules; g: a drnse arrangement of spinules: h: a dense arrangement of elaborate spinules. 1982). By convention, the term 'coenosteum' is used to describe the fine structure of the walls of the radial corallitcs as \yell that of as the material between them. The structure of the coenosteum may be similar for the radial corallite walls and the intercorallite areas, or may differ between them. For the terminogy used to describe the coenosteum, see Figure 4 . The form of synonymy used by Veron and Wallace (1 984) is followed, with the following exceptions: only the original description of each synonym is cited, except for cases when the original author expanded that description in a second publication (e.g. Brook, 1893; Verrill, 190 1) ; synonyms derived from only part of syntype series are not cited, pending lectotypification of those series; questioned synonyms are not included; new species described since that revision are added; full page and figure references are given for citations. Few changes to synonymies are made in this review, but there are exceptions, e.g. reinstatement of Acropora intermedia, splitting of A. granulosa. Some relatively obscure species named from Indonesia are not resolved in this work, but they are predicted to be junior synonyms, as follows: Acropora quelchi (Brook, 1893) (named for a specimen from Ambon identified by Quelch (1886) as Madrepora e&sa Dana, 1846) , possibly a synonym of A. secale; A. dac9lophora (Brook, 1893) (named for a specimen from Salawatti identified by Studer (1878) as A. digZt@ra), possibly a synonym of A. digitfua; A. mirabilis (Quelch, 1886) from Banda, possibly a synonym of A. jorida; A. bandensis Verrill, 1902 (named from specimens from Banda identified by Quelch (1886) as Madrepora tubkera Horn, 1861), possibly a synonym of A. tenuis; and A. cruciseptata Theil, 1932 from 'Mille Islands', possibly a synonym of A. intermedia. Family Acroporidae Verrill Genus Acropora Oken, 18 15 Acropora Oken, 1815 p. 66 TYPE SPECIES Millepora muricata Linnaeus, 1758 Genus name and type species officially validated in 1963 (Boschma, 1961; China, 1963) . "Acroporidae which are ramose, rarely massive or encrusting, branching with an axial or leading corallite (or corallites) larger than the more numerous radial corallites budded from it (or them); united by light, reticulate, spinose or pseudocostate or costate coenosteum. Columella and dissepiments absent". (Description taken from Wallace, 1978 : 277, modified from Wells, 1956 . Subgenus Acropora Oken, 181 5 Single axial corallite forms axis of branch. Radial corallites and coenosteum various. Groupings of species as used in Veron and Wallace (1 984) and additionally from Wallace (1994) are used here. Some of these groups have a unique character and are thought to be monophyletic, but some do not have a unique character and are not clearly monophyletic. One new species grouping (the Acropora rudis group) is designated. The Acropora humilis group Radial corallites short tubular with dimidiate opening; coenosteum reticulate with laterally flattened elaborate spinules; colony corymbose or digitate. "0 C C \'.\LL;\CE AND J. \VOLSTENHOLME dcropora (iicropora) humilis (Dana, 1846) ( Corallites. Axial corallites outer diameter 3.0-8.0 mm, inner diameter 1 .O-1.8 mm, primary septa present up to 3/4R, secondary septa up to 2/3R, radial corallites evenly distributed, short tubular with dimidiate openings and thickened walls; proximally on branches radial corallites ma) be in two sizes, with smaller, sub-immersed corallites interspersed amongst the dimidiate tubular corallites; primary septa to 1 /3R, secondary septa incomplete, to 1 /4R. C'oenostmm. Dense arrangement of laterall) flattened elaborated spinules, sometimes arranged into dense irregular costae, throughout. .tladrepora gernrnlfera Brook, 1892 p.457; 1893 p.142 p1.21 .bladrePora australis Brook, 1892 p.453; 1893 p.155 Coralliles. Axial corallites outer diameter 2.811.2 mm, inner diameter 1.0-1.6 mm, primary septa present up to 3/4R, secondar). septa up to 2/3R two sizes of radial corallites throughout branch, often arranged in longitudinal rows; larger radial corallites short tubular, with dimidiate openings and thickened walls; smaller radial corallites sub-immersed, primary septa of the larger corallites present up to 3/4R, secondary septa absent or a few visible up to 1/4R. Coenosteum. Dense arrangement of laterally flattened elaborated spinules, sometimes arranged into dense irregular costae, throughout. Sturdy, digitate to coqmbose colonies; large axial corallites and two distinct sizes of radial cordites are obvious; known colours cream, brown, blue, purple, cream with blue tips; occurs intertidally and subtidally on reef tops, upper slopes and submerged reefs. It is often difficult to distinguish between the two species Acmpora humilk and A. gemmfma (see remarks in Wells, 1954; Wallace, 1978 and Veron & Wallace, 1984) . Currently the species are distinguished by the consistent presence of immersed radial corallites throughout a branch in A. gemmijru. For both of these species, taxonomic resolution, including decisions about synonyms, is incomplete, pending more detailed field and laboratory studies. Acropora (Acroporu) monticulosa (Bruggemann, 1 879) (F@ 9, 10) iMadreporu monticulosa Briiggemann, 1879 p.576 Matm'al examined G47308-14 Sangihe Is. N. SULAWESI: G34173, G47316 Bunaken N.P.; G49010 Batong I.; G47315 Tg Pulisan; Corallum. Digitate from a broad base; branches up to 50mm basal diameter and strongly tapered. Corallites. Axial corallites outer diameter 1.4-3.8 mm, inner diameter 0.6-1.2 mm, primary septa present up to 3/4R, secondar) septa absent or a few just visible to 1/4R; radial Fi&pre 9. Distribution of drmpora nrontirulosa in Indonesia (main map) and worldwide (inset). corallites evenly sized and distributed, short tubular with rounded and only very slightly digitate openings, primary septa present up to 1/2R, secondary septa absent or a few just visible as points. C,brnosteum. On radial corallites, a dense arrangement of laterally flattened elaborated spinules, sometimes arranged into dense irregular costae; reticulate with less densely arranged spinules in intercorallite areas. Digitate with broad, low conical branches, sometimes appearing hexagonal at their bases; radial corallites can bc seen to be smaller and more uniform in size than those of A. humilis and A. gmrnijh; axial calices similar in size to those of radial corallites; known colours cream, brown, lavender-brown; occurs around low tide mark and just subtidally on rocky, waveswept, shallow reefs. The type locality for this species is Rodriguez in the W. Indian Ocean: however, it is most frequently recorded in the Pacific Ocean and in our sampling of Indonesian reefs, was only found on reefs near the Pacific Ocean. dcropora (ilcropora) sarnoensk (Brook, Corallum. Caespitose to caespito-corymbose, with central to side attachment; branches terete or only slightly tapering, up to 15 mm diameter. Corallites. Axial corallites outer diameter 2.74.5 mm, inner diameter 0.8-1.8 mm, primary septa present up to 3/4R, secondary septa to 2/3R; radial corallites mostly not touching on branches, tubular with round to oblique or dimidiate openings, may be interspersed with immersed corallites, primary septa present up to 1 /4R, secondary septa absent or a few just visible as points. Comosteum. Dense arrangement of laterally flattened elaborated spinules throughout; may appear costate on radial corallites. Colony caespito-corymbose with frequent branching, branches terete (same thickness throughout) and not sturdy; radial corallites separate, not touching; known colours cream or pale brown; found subtidally on most reef locations to approximately 15 m depth. Unlike other members of the species group, the species is encountered on most reefs throughout Indonesia. It occurs in a broader depth range than all other species in the group. Acmpora (Acmpora) d&tijiia (Dana, 1846) ( Material examined W. SUhIATRA. G48624-30 Padang; E. SUMATRA: G49803-13 Riau/Lingga Is; KALIhlAh'TA" G39805, G39813-6 Pulau h u t ; G50096, G50394, G50547-50 N.E. Kalimantan; N. SULAWESI: G47541 Bunaken N.P.; (347540 Tg Torowitang; C. SU-LAW'ESI: G50542-6 Togian Is: S. SUWWESI: G47542-3 Spumonde Arch.; NUSA TENGGARA: G47544 hmbok; G4863 1-2, (350393 Flores; G486 18, G48633-4 Kupang; 648635-7, G48619 lUor Is: BANDA SEz4 647035, G50810 Ambon I.; G48638 Manuk I. CoraNum. Digitate or corymbose; branches moderately tapering, up to 15 mm basal diameter. Corallites. .kxial corallites outer diameter 2.2-3.8 mm, inner diameter 0.6-1.6 mm, primary septa present up to 2/3R, secondary septa some to all present up to 1/4R; radial corallites dimidiate, evenly arranged close together. with thickened walls and little or no inner wall, so that lower wall looks like a lip, primary septa present up to 1 /3R, secondary septa present up to 1/4R. (hnosfeum. On radial corallites a dense arrangement of laterally flattened elaborated spinules, sometimes in lines; dense reticulate with elaborate spinules in intercorallite areas. Colonies digitate to corymbose; branches thin relative to those of other members of group; radial corallites closely arranged on branches; known colours white, cream or pale brown, usually with blue tips; occurs intertidally on reef flats. This species often co-occurs with Acropora pulchra and sometimes A. aspera as a shallowwater assemblage on rubble flats close to coral cays or low islands. It is almost exclusively an intertidal species. Specimens from Indonesia differ from those in the Pacific in having radial corallites more distantly spaced (not touching) and the lip-like outer wall more accentuated. =Icmpora (ilrropora) multiacuta Nemenzo, 1967 (Figs 15, 16) .icropora multiacuta Nemenzo, 1967 p. 133 p1.39 figs 1-3 ,Cfaterial examined C. SUIAWESI: G48843-52, G50334 Togian Is; NUSA TENGGARA: G48387-9 Flores. Carallurn. Irregular caespito-coqmbose colonies from a central to lateral base, with axial corallites sturdy and prominent, sometimes to the extent that the entire branch or one side of a branch does not bear radial corallites; main branches up to 100 mm in length and 15 mm diameter at base (1 0 mm in Indonesian specimens); secondary branches or incipient branches without radial corallites may be clustered around the base of the primary branches. Corulkta. Axial corallites outer diameter 2.4-6.5 mm, inner diameter 0.6-2.0 mm, primary septa present up to 3/4R, secondary septa absent or some to all present up to 1/3R; radial corallites scattered, nariform, tubo-nariform or partly appressed tubular, often oriented with opening down or across branch, primary septa just visible as points, up to 1 /4R, secondary septa absent or a few just visible as points. Coenosteum. A dense arrangement of elaborated spinules, sometimes arranged in lines, throughout. Small colonies which appear digitate because of the large size of the primary branches reiative to the secondary branches; known colours pale blue, pink, or whitish brown; occurs whtidally on submerged reef tops, ledges in walls and rocky slopes; often found in indentations or crevices in the reef surface. This species is extremely rare, being apparently absent on most Indonesian reefs. When it does occur. groups of colonies can be found, suggesting that some localised form of recruitment is involved. The Togian Islands specimens have more elongate and tapering branches than the Flores specimens, which in turn are generally thinner and more tapering than those recorded from the Great Barrier Reef (Wallace, 1978: 301; Veron & Wallace, 1984: 184) . The Acropora lovelli group Radial corallites evenly sized and shaped, appressed rounded tubular with large round openings. Coenosteum reticulate with simple spinules, sometimes arranged in rows or costae. dcropora (Acropora) glauca (Brook, 1893) ( Material examined W. SUMATRA: G49876 Padang; NUSA TENGGARA: G46700-1 Nusa Lembongan. Corallum. Corymbose; branches short and terete up to 15 mm basal diameter. Corallites. Axial corallites outer diameter 3.1-4.1 mm, inner diameter 1 .O-1.3 mm, primary septa to 3/4R, secondary septa present up to 2/3R, occasionally a third cycle is partially developed; radial corallites evenly distributed, equal shapes and sizes, appressed rounded tubular with large round openings, primary septa to 3/4R, secondary septa to 1/2R. Coenosteum. Reticulate or finely costate throughout. Colonies corymbose to anastomosed corymbose plates; radial corallites very evenly shaped and arranged and just touching; known colour pale cream, brown or dark green; occurs subtidally on reef tops and upper slopes. Remarks located on coral cays, sandy reefs or reef walls. This seems to be a species whose habitat preference is for rocky shores. It has not been The dcmpora robusta group Radial corallites dimorphic: long tubular corallites with dimidiate openings are interspersed with sub-immersed radial corallites; coenosteal structure dimorphic: costate on radials, reticulate in intercorallite areas. Acmpora (Acmpora) robusta (Dana, 1846) Bernard, 1900 p. 120 ilcmpara pondmsa Nemenzo, 1967 p.57 p1.20 Corallum. Subarborescent, the branches broad (up to 40 mm basal diameter); peripheral branches elongate, up to 250mm long; central branches may be conical and even appear digitate. Corallites. Axial corallites outer diameter 2.14.0 mm, inner diameter 0.5-1.5 mm (Indonesian specimens with smaller calice diameter than Pacific specimens), primary septa present up to 3/4R, secondary septa to 1/3R; radial corallites dimorphic: long tubular corallites with dimidiate openings are interspersed with sub-immersed forms: dimorphism not obvious on digitate central branches, but distinctive towards branch tips, primary septa of large radials present to 1 /2R, secondary septa just I isible as points in Indonesian specimens. Coenosteum. tercorallite areas. Sturdy low subarborescent colonies with digitate central branches and curving peripheral branches; known colours green with pink branch tips or pale brown; occurs intertidally or just suhtidally on shallow reef tops and edges. Remark is restricted to shallow, mostly intertidal habitats. Costate on radial corallites; reticulate with occasional simple spinules in in-'This is a common Indo-Pacific coral which does not vary greatly throughout its range. It Acmpora (Acmpora) danai (Edwards & Corallum. Low arborescent with broad branches up to 40 mm diameter, which extend mostly horizontally and proliferate into small, fused branchlets at their tips. Corallites. Axial corallites outer diameter 2.0-2.5 mm, inner diameter 0.7-1.2 mm, primary septa to 2/3R, secondary septa to l/4R; radial corallites dimorphic: long tubular corallites hvith dimidiate openings are interspersed with sub-immersed forms, dimorphism most obvious towards edge of colony, primary septa to 1 /3R, secondary septa1 cycle incomplete to 1 /4R or absent. Coenorteum. Costate on radial corallites; reticulate with occasional spinules in intercorallite areas. Colonics consist of thick main branching units which proliferate distally as short branchlets; known colours brown or pinkish-brown; occurs intertidally or just subtidally on shallow reef tops and edges. This species co-occurs with A. robusta: the two species are very similar in all characters except the proliferation of small branches at the branch tips in A. danai, and A. danai never has the greedpink colouration. On Indonesian reefs, Acropora danai is the more common species, although neither species occurs as commonly as on Pacific reefs. LVells, 1954 (F@ 23, 24) dmpora palmerae \.$'ells, 1954 p.4 10 pl. Material examined NUSA TENGGARA: G49361 Nusa Lembongan; G49359-60 Alor Is. Corallum. Encrusting, with an occasional short branch developed in some colonies. Corallites. Axial corallites if present outer diameter 2.1-2.8 mm, inner diameter 0.9-1.3 mm, primary septa present up to 1/2R, secondary septa to 1/4R (not observed in Indonesian specimens); radial corallites showing the dimorphic character in some parts of colony, but mostly sub-immersed with nariform or just discernible dimidiate openings; primary septa of large radial corallites present up to 1 /2R, secondary septa just visible as points in Indonesian specimens. Coenosteum. Costate on radial corallites; reticulate with occasional simple spinules in intercorallite areas. Sturdy encrusting colonies, up to 2 m diameter; known colours bright green or brown; occurs intertidally or subtidally on shallow reef tops and edges, especially in regions of strong current. There remains some doubt as to whether this is a separate species or simply a strongwater form of Acmpora vvbusta. All specimens examined occurred in habitats experiencing strong currents, where this species was abundant, co-occurring with an encrusting form of A. pal$era. Acropora (Acropora) intermedia (Dana, 1846) ( Corallum. Arborescent, with branches given off at wide angles (45" to 90"); branches with basal diameters up to 25 mm and tapering gradually. Corallztes. Axial corallites outer diameter 2.5-4.0 mm, inner diameter 0.8-1.5 mm, primary septa present up to 3/4R, secondary septa from absent to 1 /4R; radial corallites dimorphic: long tubular radial corallites with dimidiate or oblique openings, primary septa to 2/3R, secondary septa to 1/4R (less well developed in Indonesian specimens); between these are immersed corallites in which septa are hardly L-isible. Comosteum. Smooth costate on radial corallites; reticulate with occasional simple spinules in intercorallite areas. C. C. \V.%LL,.XE XVD J. \VOI,STENHOLME Arborescent, forming compact colonies or large thickets; radial corallite dimorphism and the dimidiate openings of large radials clearly visible under water; known colours cream, brown, pale