. BRYOZOA FROM HERON ISLAND. GREATBARRIERREEF RYLANDAND HAYWARD J.S. PJ. kviand, J.S. & Hayward. >>.J. L99206 29: Bfyozoa fromHeronIsland,GreatBarrierReef Memoirsofthe QueenslandMuseum32(1): 223-301.Brisbane.ISSN0079-8835. Eighty-onespeciesofBryozoaaredescribedfromshallowreefhabitatsaroundHeronIsland, Queensland.Fourteennewspeciesaredescribed:Putllinadecipiens.P. egretta, P. vulgaris, Cettepotaria desperab'tlis, Robertsonidra novella, Parasmittina galerita, P. onychor- rhync/ui, P. turbula, Pleurocodonellina clavicula. Microporella fimbriata, Celleporina reginae, Rhynchozoon ardeolum, R. limatulumandR.scopulorum.Twenty fourspeciesare recorded for the first time from Australian waters. 'Qfieron Island, Great BarrierReef, Bryozoa, taxonomy,newspecies. J.S. RylandandPJ. Hayward, Marine, EnvironmentalandEvolutionaryResearchGroup. SchoolofBiologicalSciences, UniversityofWales,Swansea,Singleton Park, SwanseaSA2 8PP, UnitedKingdom; 10June, J99J, The coral-associated bryozoan fauna of the some 215,000knr. It is to be expected that the Great Barrier Reef (GBR) is undoubtedly very bryozoan faunawill vary with latitude and, most diverse, probably comprising several hundred species being essentially subtidal, would be ap- species. It is, however, poorly known. Thus, in propriately studied and collected by scuba. The the iate I9th century, when the rich bryozoan present contribution, in which we describe 81 of Victoria and, toaslightly lesserdegree. species,ismanifestly preliminarybeingbasedon of New South Wales and South Australia, was astill incompleteexamination ofspecimens col- beingdescribed,theGBRbryozoanswereknown lectedintertidallyonHeronIslandreef,oneofthe only by afew specimens from HMS Rattlesnake southernmostintheGBR,mainlyoverafewdays (Busk, 1852a).fromPortDenisonandHolhourne in 1972. Island (Haswell, 1881) and from A.C. Haddon's Heron Reef is one of 16 comprising the collections in Torres Strait (Kirkpatnck. 1890a). CapricornGroupwhich,togetherwithfourofthe d This lackofstudy continued through mostofthe Bunker Group, he between latitudes 23 and 20th century, with coastal Queensland or GBR 24°S atthesouthernendoftheGBR.Thesereefs , *.roans being described in only a few short are separated from Breaksea Spit (Sandy Ci papers(Livingstone, 1926;Hastings, 1932;Silen, to the southeast and from the mainland coast in (lLlJi4v2i;ngRsotsosne?,1917942;7R;ylDaanldl,&19S7t4erp1h9e8n4so)na,nd19l5is3t;s tnehle,newihgihlbeoutrhehoSowdaoifnGlRaedesftsoneliebyaCbuoruttis1C50km Hall, 1984; Winston, 1986). Consequently, the northwards across the Capricorn Channel. The viewprevailedthatbryozoanswerepoorlyrepre- 200m isobath lies some 16-25km east of the sented in coral reefs generally and in the GBR Capricorn Group, whilst the mainland is about particularly (Ryland, 1974). That this must have 70kmtothesouthwest. Amapofthegroup, with & been erroneous was evident from Maxwell's bathymetry, is givenby Jell Flood (1977) and (1968) study of sediments in which bryozoan Mather& Bennett (1984). fragments, representing a wide diversity of Mean watertemperatures are26-27°C in sum- species, formed an importantconstituent. Recent merdropping to 20-21°Cin winter,buttempera- semi-populardescriptionsoftheGBRhavebeen turesover the reefflat may exceed 32°C ordrop gtven byBennett(1971),Endean(1982)andTal- to 17°C, or even lower (Endean et al. 1956). ? bot (1984) providing useful background infor- Prevailing winds are southeasterly, or from be- mation onTthe fauna generally but little oo the tween southeast and east during summer Low- Bryozoaspecifically. amplitude ocean swells thus approach TheGBRisextensive,stretchingsome 1900km predominantly from roughly the southeast The from Lady Elliot Reef(24°07'S) slightly south East Australian Current outside the shelf edge > oftheTropic ofCapricorn, to the WarriorReefs flowspolewardsbutthere islittleinformationon andBramble Cay in the GulfofPapua (9°09TS). thecurrent patterns within the southern GBR. In GBR The reefs are dispersed over, and alongtheedge the central the residual flows are deter- of, the continental shelf and occupy an area of mined by prevailing winds, setting northerly 224 MEMOIRSOPTHEQUEENSLANDMUShUM duringperiodsofsteadytradewindsbutsoutherly cyclones, e.g. 'Emily* (Apr 1972), 'David' (Jan during light or variable breezes (Wolanski & 1976) and 'Simon* (Feb 1980). each time being Pickard. 1985) Releasesofsurfacedrifters in die dredged clear afterwards. The boat channel was Capricorn Channel suggested a nett southerly extended in 1987-8S (Flood. 1989) and is now movement (Woodbcad, 1970). Tides are semi- associatedwithalongandsubstantialjetty These . diurnal,though successivetidesfrequentlydiffer developments haveaffected sediment deposition inheight:meanamplitudesare2monspringsand (Coutlay & Flood, 1981). a symptom of a sub- Ira on neaps. Tidal currents set westerly on the ally altered flow regime over the southern flood* easterly on theebb. cay-sidc flat. Most ofthe Bryozoa described in Heron Island, the cay (23°27"S. 151*55*®. is this paperwerecollected from this area in 1972. situated «*t the leeward (western) end ofan egg- Waternolongerdrainsradiallyfromthereefhere shaped lagoonal platform reef (Jell & Flood, but (1988) flows strongly along the flattow 1977), toughly 8.5 by 4km with the long axis thechannel.Thereefflatprovided anchcollect- orientatedESE-WNW(Fig. 1 1. Atitseasternend. ing areain 1972 but seemedto havedel Heron Reef is separated from the smaller Sykcs markedlyby 1988,evenbeforetheconsequences Reeffwith which itsharesarecfal platform,bya of the 1986-87 developments (already apparent 3km wide channel of about 15m depth (map in OD water flow) could have affected the living Jell & Flood, 1977). Thesouthwesternquarterof coral framework. HeronReefisseparatedbyachannel,about700m The reefflat extends seawards from thecay to wide and 30m deep, from Wisiari Reef. The theinnersideofthereefrim.Atlowrwatersprings, disposition of the two reefs ensures that the awayfromtheboat harbour, waterdrainsthrough western extremity ofHeronReef, and especially gaps and channels in the rim, but the flat never the northern aspect of it, is well sheltered from wholly dries. The innerpart ofthe flat is largely direct impact of the tradewind swells, although sandy, with patches of coral nibble and some •vavesfromthesoutheastarerefractedaroundthe livingcoral,e.g. Poritexeylmdrica. Theouter flat reef. Wave-transported particles are depositedin is characterized by living coral, extensive the vicinityofthe cay (Flood. 1974). During the developmentofcrustosecorallinealgae,anddrifts ehk water fromthereefdrainsinaradial manner ofcoral shingle; »nd is restricted to small pools (exceptneartheboatchannel,seebelow)untilthe and narrow channels. In 1972 the flat at the rimhemmesexposed. A shallowlagoonoccupies westernend (beyond theboatharbour)was exten- the east-central area of the reef. At spring tides sivelycarpetedwithalevel forestofAcroporabut thereisanextensiveperipheralreefflat,especial- shinglehasincreasingly accumulated since then, ly at the western end, coveted by 0,5m ofwater The reef rim is higher than the upper level of ox less. The edge of the reef is then accessible livecoralontheouterflat. Itssurfaceiscemented from thecaybywading. Accesstootherparts of with crustose coralline algae, and /oanthids the reef edge at low tide, and tothe drop offfor (especially Pulvthoaspp.)areconspicuous.Coral ib«, must beby boat. shingle, coral boulders (derived from Acropora Most descriptions of Heron Island refer more hyacinthus heads), and sometimes large blocks to thecay thanto the reef(e.g. Steers, 193*) but derived from bummies (plate 30B in SavjHo- brief accounts of the reef have been given by Kcnt, 1893), accumulate on and just inside the Endean etai. (1956), Cribb (1966), Jell & Flood rim.Whiletherimpavementisde-voidofhabitats (1977) and Mather & Bennett (1984). Important suitableforbryozoans,thebouldersconstitutethe man-made features are the boat channel and the richestmtertidal habitat for them cayrswesternretainingwall. Marineengineering Thereefslopeisthesublittoralextensionofthe works up |o 1980 were summarized by Gourlay reefnm Onthewindward(southeasterntosouth- & Flood (1981), with particular reference to the western)sideofthereef,theupperslopehasspur stability of the cay, aidiough iJ>ere have been and groove form and the gradient varies from 1 consequences on the reef flat to the south ofthe in 20 in the southeast to I in 4 southwest of the cay. In 1945 a gap was blasted in the reef rim, cay (Jell & Flood, 1977). When accessible in oppositethe northern tipofWistari Reef, topro- calm weather the coral growing on the spais vnte accessforsmallboats. A wreck(still there) would undoubtedly prove a rich habitat for was positioned to provide shelter. The gap was Bryozoa. On the lee side ofthereefthespur and extended in 1966-67 to provide a dredged boat groove formation does notdevelop; rather there channel and harbour. The channel has sub- is extensive growth of tabular corals, such 3s sequently been fiUed with sand mobilized by oparu hyacinthu.%. In 1972 some bryozoans BRYOZOA FROM HERON ISLAND 225 argassum reel platform Heron Island and Reef km 1 23°30'S 152°00'E 26^^^ cay B 21 23-24 Heron 200 m FIG. 1. Heron IslandandReef,showinglocationofsamples. ProfilesfromJell & Flood(1977). were collected by snorkelling and scuba from 1972), by 1988 had developed an abundant and under such tables, and photographs show the colourful sessile faunaofgreatdiversity. richness there of sessile fauna. It is such tables In 1988 occasional pieces of drift Sargassum that,whenstruckbytropicalcyclones,arebroken heavily colonized with bryozoans suchasAetea, free and hurled onto the edge of the reef. They Crista, Lichenopora and Membranipora and ultimately settle in the only stable position, with hydroids Eudendrium and Plumularia were col- the formerattachmentfacingupwards.Thecryp- lected on thebeach ofthecay. At thelime itwas tic surface is usually somewhat concave, such not known where the Sargassum was growing. that the boulder rests on its rim; irregularities Subsequently, a bed of Sargassum has been lo- ensure that water circulates through the space, cated by Lin Baldock and Myriam Preker in keeping thebouldersurface clearofsediment. In 10-15m waterin thechannel between Heron and this dark, protected habitat ascidians, bryozoans Sykesreefs.Thespeciesheredifferfromthoseof and sponges develop in profusion. Thus the boulders and discovery of the Sargassum bed boulders in the BluePools area, northofthecay, should greatly benefit future studies on the which were deposited by cyclone 'Emily' (Apr Bryozoa. MEMOIRSOFTHEQUEENSLANDMUSEUM MATERIALS tal. Fragments of typically subtidal erect Bryozoa, such as Triphyllozoon and violet With the exception of two species of Bugula lodictyum, were also picked up here. (These found on boulders near Blue Piools in 1988, the boulderswereexaminedin 1988,havingbeen bryozoans described in this paperare from 14 of onthereeffor 16years.Thefaunaisstillbeing the 28 samples obtained by JSR in 1972 These studied). are identified by sample numbers (Fig. 1) as 2J. 14Apr, 1972.Reefcrestsouthofthecay.Most follows: ofthe flat approaching the crest at this point was level,easy to walk on, ratherthan being 2. 9 Apr, 1972. On the reef flat south ofthe cay. a forest of heads. Several coral boulders Bryozoawerecollectedonpieceschippedoff derived from Acropora heads were present. tabular Acropora, in situ, or from dislodged The living coral of the crest tended to form heads resting on the sand. Bryozoans were layers (almost shelves). While water on the presentonundersurfaces,thoughrarelyabun- flatappearedtoebboverthecoral,onthecrest dant, andlesscommonthansponges. itnoticeablypercolatedthroughthecoral.The 5.11 Apr. 1972. Onthe reefflatWWWofthecay space matrix wouldseemidealforbryozoans Flat plates ofcoral, the outer parts spread OS being fairly dark and with long periods of horizontal laminae, the inner were convoluted, waterflow.Thecoral heads typically, though formingrecessesandcleftsshelieringMargaret- nut invariably, displayed a lower surface 6. 11to,Aplrac,e1co9r7a2l.sN(Pehairdo5Ioopnortihdeaer)eTeafnfdlactelWluNlarWineos.f wzointahtiloin,thwoitthhamtmheiopneriapnhderatlheficnegnetrrsecorveegrieodn thecay.PlatesofEchinoporawithencrusting while, with Fitogrotw lubes, sponges, com- bryozoans on thelowersurface. pound ascidians and Bryozoa. The sample 8. 1 1 Apr, 1972- Near5 and 6. Theflat herewasa was a piece of boulder showing a level platform of abraded Acropora with a coral/bryozoaninterface. maze of cavities underneath, and coral 22.15 Apr, 1972. Reefcrest at the cleft, northeast 'fingers' risingfromIhcsurface.Theencrust- of(hecay.Thecresthereismorecomplexthan ingfaunaseemedpoorerthanunderindividua] ji .M.Thereistheactualedge,markedbysurf, tables. |hen a moat;thecoralthenrisesonto thecrest 11.12Apr, 1972.Onthereefflatwestofthecay. which merges intothezoneofcoral boulders to the north of the boat channel. Pari of a and rubble (see profile D, fig. 1, fromJell & well-developed Acropora head which had Flood, 1977).Alongthecrestcoralwasdying tippedwhensteppedon. Theouterpartswere back,app;irentlybecausecyclone*Emily*had coatedwithathin,filmyprussianbluesponge. altered the drainage pattern. leaving thecoral Several Reteporella graeffei and incrusimg heads dry and dying; or live coral had been specieswerepresent. flattened by pounding with the Acropora 12. 12 Apr, 1972.Onthereefflat, near 11.Below boulders produced by the cyclone. Sample the actively growing Acropora head, sup- was from these boulders, though most Iodic- ported by a slenderpedestal, was alayerrep- lyum fragments were unattached. resentinganearliergrowthlevel.3-5cmthick, 23.16 Apr, 3972. Reef crest soum of the cay; withsedimentlyingon its uppersurface*The collection made by turning boulders. Tide lower surface was white, lacking encrusting pOOf; reefedgenotexposed; waterrunningoff coralline algae, butbearing Tutmtrea, spon- thereefasa sheet. ges. Filograna, a brachiopod,andbryozoans. 21.17 Apr, 1972. Near 23; from well-incrusted Below this wascoral rubble. boulders. 14. 1l2arAgperA,cr1o97p2o.raNehaerad12w.hPiicehcehsadbrboekecnomferofmreea 25.1B Apr, 1972.Collectionfrom4.5-9matcom- mie made by D.R. Robertson. Included andturnedupsidedown,thoughcontinuingto Bugula dentata, Nellia simplex and grow, Phidoloporidac. 16. 13 Apr, 1972. Crest to the westofthe cleft in the reefedge, northeast ofthe cay. The crest 26. 18 Apr, 1972. Near25, about3mdepthonthe here was strewn with boulders deposited (or slope redistributed) by cyclone *Emily' (1-2 Apr). The sessile fauna on the Acropora was Holotypes and paratypes of the new species protectedbytheknobblysurfaceofthepedes- describedhere arein the Queensland Museum. . BRYOZOA FROM HERON ISLAND 227 ACKNOWLEDGEMENTS withlobesextendingbetweenzooidrows,roofed by finely granular calcification; ooeciostomes We aregrateful to the Nuffield Foundation for situated at edges of brood chamber, between the provision ofa Travelling Fellowship to JSR zooid rows. in 1971/72,tothe Royal Society foratravel g in 1988,andtotheAustralianBiological Resour- Lkhenopora Defrance, 1B23 cesSurveyforgenerousfinancialsupportforour research. Thanks are also due to the Director of With thecharactersofthe family, theHeron IslandResearch Station, Dr IanLawn, Tvpespecies.LichenoponttarbiruitaDGXTWCc, and to Miriam Prekcr, who kindly supplied daia 1823. on the distribution of Sargassum, and Dr P.G. Flood forfreelygivenadviceandinformationon Lichenopora novaezelandiae(Busk) the physical environment of Heron Island. PJ. (Rg.2a,b) Chimonidesand Mary ESpencer-Jones(Natural History Museum, London) were most helpfMulRin D/scoporeiUi rwoezelandiue Busk. 1875: 32. pi. 30, facilitating the loan oftype specimens. Dr fig. 2. I'ordy(SchoolofBiologicalSciences.University Uchenopom mnaezelanJiuc: Brood. 1976: 299. ofWales, Swansea) is especially thanked for his 17A-C(notfigs 17G-I.=DisporeUasibogaeButg); valued expertise in scanning electron microg- Hayward & Cook, 1983: 137. raphy. Description SYSTEMATICACCOUNTS L novaezelandiae, asdescribedand figuredby Busk (1875) and Harmcr (.1915), has uniscn;il Thetaxonomicorderadopted here followsthat zooid rows and a simple, rounded ooeciostome. established by Gordon (1984, 1986, 1989b), Brood (1976) appears to have confused his Taxonomic diagnosesare providedatfamily and figureswiththoseofDisporeUasibogae asuper- r genus level, and the species descriptions and ficially similar species in which the zooid row:. measurements are based on Heron Island are always biseriaJ. Colonies are typically oval specimens. The synonymies given for each anddomed, and may reach 1Omm in length. This species are deliberately selective, being limited speciesisprobablyquitecommoninshallowreef to the original description and the most useful, environments, but it is generally inconspicuift • recent accounts. Unverified synonymies have Several large colonies were present in the inter- been avoided. The occurrence ofeach species at stices ofAcropora in sample 2. HeronIsland,anditswidergeographicaldistribu- tion, are briefly noted It is intended that a more Distribution precise account of the ecological distribution of It isdistributed throughout die westernPacific the bryozoan fauna will be prepared after the fromNewZealandtoJapan,andwestwardstothe Completion of the present, continuing research eastcoast ofAfrica. project. GYMNOLAEMATA Class Allman, 185o Class STENOLAEMATA Borg, 1926 OrderCHEILOSTOMIDA Busk, 1852a OrdCTCYCLOSTOMJDA Busk. 1852a Suborder ANASCINA Levinsen, 1909 Family LICHENOPOR1DAESmkt, 1867 Supcrfamily MEMBRANIPOROIDEA Busk. 1854 Colony encrusting, regularly circular or ova!, Family CALLOPOREDAENorman, 1903 occasionally developing as a Cylinder around erect substrata; concave or domed, nodular or Colony encrusting, forming coherent or dfe mamillate, often lobed, bordered by a peripheral junct sheets, or reticulate to umserial runners, dj laminaofcommonbasal wall. Autozooidsradiat- erect,developingbilaminarplatesorarborescent, ing fromcentreofcolony,sometimes in irregular vinculariiform growths, attached by an encrust- quincuncial series, more usually in connate, ing base. Frontal wall ofautozooids with exten- unisenal ormultiserial rows. Extrazooidal space sivemembrane, sometimes overarchedbyspines •en zooid rows divided by calcified struts, but always conspicuous; gymnocystal and/bfl definingpolygonal spaces referred to as alveoli. cryptocystul calcification usually present, often Brood chambers originating in centre of colony. well developed. Spines present or absent. MEMOIRSOFTHEQUEENSLAND MUSEUM 228 S«*v* V &&5mBBmm FIG. 2. a,b, Lichenopora novaezetandiae: a, whole colony, X.9; b, detail showing ooeciostomc between two /.ooid rows, X30. c, Antropora granuitfera, X80. t± Purrllisina vitnirostris, X60. c, Cranosina coronata, >:50. f, Microporavariperforata, X75. KRYOZOA FROM HERONISLAND 22V Avicularia adventitious and/or vicarious, some- Ovicell prominent, hyperstomial. Basal pore times lacking. OviceJIsgenerally present, hyper- chamberspresent. stomial, or partly immersed, reduced. Vertical Type species- Membranipora curvirosvis walls with large basal pore chambers, or mural Hincks, 1862- septula. Parellisinacurvirostris(Hincks) Antropora Norman. 1903 (Fig. 2d) Colony encrusting. Autozooids with well Membraniporacunirostris Hincks-, 1862: 29: 1880a: developed cryptocyst; gymnocyst negligible or 153, pi. 20, figs 5,6. absent.Nospines.Aviculariainterzooidal,small, Ellisinacunnrosins: Harmer, 1926: 228,pi.14, fig.7, sometimes lacking. Ovicell endozooidal, its Parellisina curviroslriy. Cook, 1968a: 156, text-fig. presence indicated by a slight thickening at the 16;Winston, 1984:7,fig. 14;Winston&Heimbexg, distal endoftheautozooid. Basal pore chambers 1986; 6. figs 7,8. present. Type species: Membrampora granulifera Description Hincks, 1880b. Colony forming small, unilaminar patches Autozooids broadly oval or pear-shaped, com Antropora granulifera (Hincks) monly 0.5 X0.3mm, the extensive frontal (Fig. 2c) membraneborderedby araised muralrim; a pair ofdelicate, evanescent, distal oral spines present Membranipora granulifera Hincks, 1880b: 72, pi 9, in early ontogeny. Avicularia frequent; distinc- Jig. 4. tive:rostrumacutetofrontalplane,0.25mmlong. Antroparagranulifera:Harmer. 1926: 232,pi. 14,figs laterally curved: associated with a kenozooidal 11-14;Cook 1968a: 138.text-fig. 9 polymorph, with a rounded opesia, visible distal to the rostrum. Ovicell relatively small, the Description tooecium membranous frontally, exposing Colony forming flat, unilaminar sheets. granularentooecium. Autozooids irregularly oval to hexagonal, each with a raised crenellated rim; 0.4-0.5x0.2- Distribution 0.3mm. Cryptocyst occupying about half total Thisfamiliarspecieshasapantropiealdistribu- autozooidlength, flatorslightlyconcave,coarse- tion,ranging into temperate regionsin the north ly beaded; opesiasubtriangular. Atthedistalend east Atlantic and perhaps elsewhere. It forms ofeach autozooid is a pair(rarely one) ofsmall, small, and generally inconspicuous, colonies on interzooidalavicularia.eachbuddedfromadisto- hard substrata, particularly biogenic carbonates. lateral pore chamber; rostrum acute to frontal It is common atHeron Island, occurring in seven plane, directed distalty or disto-medially, ofthe sample stations reported h 0.07mm long, with a short triangular mandible. CrassimarginatellaCanu, 1900 Distribution Antroporagranulifera ispossiblycircumtropi- Colony encrusting; or erect, attached by an cal in distribution. It has been reported from encrusting base bilaminar or vinculariiforni. ? Madeira, West Africa, Sri Lanka, Indonesiaand Autozooids with extensiveopesia, borderedbya the tropical eastern Pacific, but has not been narrow,granularcryptocyst; gymnocyst variably recordedpreviouslyfrom theGreatBarrierReef. developed. Spines present or absent. Avicularia It was found at two stations on Heron Island vicarious Ovicell prominent, hyperstomial, or (samples2and 16),onthereefflatto thesouth of small andcap-like.Verticalwallswith basalpore the cay, and on thereefedge to the northeast. chambers or mural septula. Type species: Membraniporacrassimarginata PareJIisinaOsburn, 1940 Hincks, 1880b Colony encrusting. Autozooid with narrow Subgenus CorbulellaGordon, 1984 cryptocystalrim,andminimalareaofgymnocyst. Spines reduced or absent. Avicularia vicarious, Autozooids with well developed gymnocyst, large, each associated with a small kenozooid. and numerous marginal spines. Avicularia 230 MEMOIRSOFTHEQUEENSLANDMUSEUM vicarious, with proximal opesia bordered by spines. Ovicell prominent, hyperstomial, with a broad frontal fenestra, Type species: Membranipom corbula Hincks, 1880c. Crassimarginatella (Corbulella) corbula (Hincks) (Fig. 3) MembraniporacorbulaHincks, 1880c;378,pi. 17.fig. 6. Crassimarqinatelta \Carbttlella) corbula. Gordon. 1984: 29, pi. 3, figs D,E; 1986: 32,pi.5, fig. A. Description Colony encrusting, forming a small, flat, unilaminar sheet Autozooids oval, 0.5X 0,35mm, with large oval opesia, a narrow, granularcryptocyst and a reduced, smooth gym- nocyst. Twelve to 18 pairs of spines distributed around the opesia, the distal one or two pairs stout,erect,therestthin, incurvedoverthefrontal membrane. Ovicell spherical, with a transversely oval frontal fenestra, its distal edge often developing a short umbo. Avicularium slightly largerthan autozooids, its distal halfcomprising a raised, smooth-edged rostrum, supporting a FIG. 3. Crassimargmotella(Corbulella)corbula. semiellipticalmandible;proximalhalfconsisting of a shortened opesia bordered by three or four Cranosina coronaia: Winston & Hcimberg, 1986: 6, pairs ofcurved spines. figs3-6; Hayward, 1988: 281. Distribution Description Thisspeciesiswidelydistributedindiewestern Colony forming flat, unilaminar sheets. Pacific from Japan to New Zealand. A single Autozooids irregularly ov^al to hexagonal. colony was present in sample 16, from the reef separated by distinct grooves; 0.65- edge northeast ofthe cay. 0.7Xc.0.4mm. Cryptocyst coarsely beaded, the beads aligned in ridges, directed medially and CranosinaCanu & Bassler, 1933 impartingacrenulateedgetothecryptocyst. Dis- tal etid of autozooid raised, with a hood-like Colony encrusting. Frontal membrane of borderofsmooth,gymnocyslaicalcificationsup- autozooid underlainby a broad, peripheral cryp- porting the operculum. Avicularium developed tocyst; gymnocyst absent. No spines, Avicularia from the distal pore chamber ofeach autozooid, interzooidal, typically one budded from each its cystid not clearly distinguishable from the autozooid; mandible setiform. Ovicell reduced, distal wall ofthe autozooid; rostrumtransversely cndozooidal, or lacking. Large basal pore-cham- orientated, at a slight angle to the frontal plane, bers present. constricted medially, its disUil end flared; man- Typespecies.MembraniporacoronaiaHincks, dible setiform, very finely toothed, about0.4mm 1881a- long. Cranosinacoronata(Hincks) Distribution (Fig, 2e) A single small colony of this species was present in sample 16. Itisdistributed throughout Membranipora coronaia Hincks, 1881a: 147, pi. 10, the Indo-West-Pacific region, from the Philip- fig- I. pines to Sri Lanka and Mauritius. Also reported i BRYOZOA FROM HERON ISLAND 231 fromPuerto Rico (Osburn, 1940) andVenezuela abundant on Mauritian reefs, as part of a (Winston, 1986), bryozoan sward developed beneath coral boulders (Hayward, 1988). FamilyQUADRICELLARIfDAEGordon, I9S4 Superfamilv BUGULOIDEA Gray, 1848 Colony erect, branchings pointed. Autozooids Family BUGULIDAE Gray, 1848 elongate, opesiae extensive; cryptocyst moderately to well developed; gymnocyst Colony erect and branched, unjointcd, reduced. Avicularia adventitious, or absent. unilaminar, attached by rhizoids. Zooids long, Ovicells present or absent. Ancestrula resem- parallel-sided, with almost all ofthe frontal sur- bling later autozooids. but with a tubular face membranous; lateral walls lightly calcify;) proximalportionrisingfromanunealcifiedstem. marginal spines usually present. Pedunculate 'bird's head' avicularia characteristicallv Nellia Busk, 1852b present, Ovicells independent and hyperstomial. withthe cctoocciummembranous. Colony erect, branching, jointed; internodes square-sectioned, consisting offourlongitudinal BugulaOken, 1815 series of autozooids, arranged in alternating, back-to-back pairs. Autozooids with well- developed gymnocyst; opesia with broad, Colony erect, growing from an upright an- cestrula, branching; attached by rhizoids which proximalborderofcryptocystandsurroundedby raised mural rim. No spines. Avicularia adven- issue from frontal, lateral and basal surfaces of theautozooids Thelatterarrangedintwoornune titious- Ovicells small,partly immersed. series, alternating; boat-shaped, with the Typespecies: Nelliaoculato Busk, 1852b. proximalendforkedandthedistalendofthenext lowest zooid wedged into the fork, extending Nellia tenuis Rirmer beyond it on the frontal side; with a row of (Fig. lOci unipnriHjs. nr one to (wo multiporous, septula. Seen from the front the zooids are usually trun- NelliatenuisHavmsx* 1926: 245, pi. 14, Hgv 16-17. cate distally and slightly attenuate proximally. NelliatenuisHayward,1988:286,pi 1,fig a;Gordon. Basal and lateral walls lightly calcified, the 1989a:450. fig.3. membrane occupying most of the front: rjfil closed by a sphincter and no operculum can be Description distinguished. One or more spines may be Colony delicate, inconspicuous, formed from present, usually confined to the distal angles of internodes l-4mm long, G.25mra wide, dividing the zooid. In most species, a pedunculate dichotomouslyatinfrequentintervals,mostoften avicularium shaped like abird's head present on developing simply an undivided series oftwo or the side of all or many zooids. Ovicell hyper three internodes. Joints between internodes con- stomial. with calcified endooecium and si'.ting ofslender,cuticulartubes; each internode membranous cctooccium; typicallyglobular, but finely tapered proximally. Autozooids about sometimes reduced to a hemisphere or less, 0*3 X0.25mm. the narrow, oval opesia compris- closed by the inner vesicle which sometimes ingaboutthree-fifthsoftotal autozooidlength A forms the majorpart oftbe ovicell. pair of avicularia at the distal end of each In bi&erial speciesthearrangementofzooidsat autozooid;rostrapointed, hooked, at rightangles a bifurcation usually conforms to one of three to long axisofinternode. patterns, originally described by Harmer (1923 as types 3, 4 and 5. The bifurcations are best Distribution studied from tnr basal side in stainedandcleared Nelliatenuisisprobablyquitecommoninshal- preparations, but can generally be observed in a low reefal habitats. At Heron Island, il was piece ofa clean specimen viewed by transmitted present in samples 14 and 24, from the reef fl:i; light. The pattern of consecutive bifurcations is west ofthe cay, and the reef crest |o the south. laterally reversed, so that the bifurcations imme- Harmer(1926)had fragmentary specimens from diatelyaboveandbelowanygivenonearemirror three localitiesinthe Indo-Ma1aysianregion,and images ofit, For descriptivepurposes the zooids listed a fourth from the SouthChinaSea. Ryland involved in the bifurcation are distinguished by (1984) illustrated specimens from Fiji. It was tenets (Fig. 4). The first zooid from which two 232 MEMOIRS OFTHEQUEENSLANDMUSEUM zooids are budded is referred to as A, ihe one Description zbeosoiiddes aitb(owvheicAhaanldsoBbuadresCtwaon)dasDBr.esTpheectoivuetleyr cyCotolospniyratlulfitnegd(onfotbroannachsetsal;k,towi1t0hcsmo.mBertaenncdheens- whiletheinnerzooidsareEandF. Inbifurcations narrow, of uniform width, the zooids biserial. uftype 3 theaxil isformedbyzooids E and F. In Bifurcationsoftype5,i.e.,withtwozooidswhol- type 4 the axil is formed by F and G (G being ly enclosed, most obvious in basal view. Zooids immediatelydistal toEinthesameseries).Zooid 0.6X0.25mm (basal), in Heron Island material. Eisthusexcludedfromtheaxil,andtheproximal Opesiaoccupyingthree-fifthsormoreofthefron- partofGconnects withF. Intype5 theenclosing tal surface; the external margin of the zooid in- process hasbeen furtherextended so thatboth E rolling proximally, narrowing the opesia. Inner and F arc completely surrounded, and the axil is distalanglewithonespine,outerwithtwo,some- formed by G and H (Fig. 4). It should be noted, times long, andjointed at the base; a third outer however, that the connecting portion between G spinesome way below the other two. The spines and H may be very slender In a furtherdevelop- ofequal size on both sides of the branch, or the mentoftheenclosingprocess,severalzooidsmay outerones (with reference to the proximal bifur- be surrounded; the branch then becomes quad- cation) much larger. Avicularia of two kinds: nserial below thebifurcations. ordinary marginal aviculariaattachedabouttwo- Type species: Sertularia nentina Linnaeus^ thirds way down the zooid, a little above orjust 1758. below the vortex of the opesia; giant avicularia present or not. Ordinary aviculariaabout0.2mm Bugula dentata (Lamouroux) inlength,alittle lessthan thewidthofthebearing zooid atthepointofattachment; dorsalprofileof (Fig. 4) rostrum straight, its tip abruptly hooked (rectan- gular).Giantavicularia,whenpresent,mostoften AcamarchisdentataLamouroux, 1816; 135,pi. 3,figs replacing normal avicularia on the two outer 3ab. zooids (C, D) at bifurcations; much longer than t Bugula dentata: Busk, 1852b: 46, pi. 35, figs 1-5; the width of the bearing zooid; its entire upper Harmer, 1926: 439 (cum syn.), pi. 30,figs, 5,6; pi. profile convex, the rostral tip sometimes with 32, figs 21-25; Ryland 1974: 343; 1984: 68, fig. 4; lateral cusps; the mandible clavate, with a weak Winston, 1986:6. terminal point (Harmer, 1926, pi. 32, figs 21,23, Bugulasp.:DQ&k, 1971,colourplate31 andrearcover, 25)» Ovicells globose, attached somewhat obli- Coleman, 1977: 80(colourplate), quely overthe innerdistal angle (Harmer, 1926, FIG. 4. Buguladentata. A,Groupofautozooids,with ovicellsandavicularia. B, Autozooidsinlateral view. C, Avicularium. D. Basal viewofadichotomy.