MEMOIRS OF THE QUEENSLAND MUSEUM BRISBANE VOLUME 47 15 AUGUST 2001 PART 1 THE AUSTRALIAN ASCIDIACEA PART 4, APLOUSOBRANCHIA (3), DIDEMNIDAE PATRICIA KOTT Kott, P. 2001 08 15: The Australian Ascidiacea part 4, Aplousobranchia (3), Didemnidae. Memoirs of the Queensland Myseun 471): 1-407. Brisbane. ISSN 0079-8835. This fourth pact of a monograph of Ascidiacea in Australian waters treats the Didemnidae which contains some of the smallest and most simplified zooids, and most extensive colonies and prolific replication rates known in the Class. The family is more specivse than others, largely as a result of diversity in Indo-West Pacific (including northern Australian) tropical waters where, despite a short free-swimming larval life, species have a wide geographic range. In Australia, indigenous species generally are found in the more temperate waters of the southern halfofthe continent. No evidence of patitropical range or of Atlantic species of Didemnidae exists in the western Pacific or eastern Indian Ocean, The affinities of the family with others in the Aplousobranchia are not clear, although a high vanadium content in Leptoclinides suggest an early origin from a Diazana-like ancestor. Intra-familial relationships are equally equivocal, Although there seems to be a trend to reduced zooid size trom Atriolwn and Leptoclinides to Polysyneraton, Didemnunr and Trididemnmum, similarities could be the result of convergence rather than evidence of phylogenetic affinity. C/ire//a gen. noy,, Lissoclinum and Diplosoma have equally equivocal relationships with one snother and with other genera. Of the 202 species described, 51 previously were known to oceur in Australia, 35 were known only from other parts of the western Pacific and 116 are new. Colonial organisation, spicule size, form and distibution, and larval and zooid morphology of newly and previously recorded material have been serutinised for taxonomic implications. Eight genera, Arriolim. Leptoclinides. Polvsyncraton, Didemnum, Trididemmin, Lissoclinum, Clitella gen. nov. and Diplosoma are documented. In both tropical and temperate waters Didenmuin is the most speciose genus in the family. Biological data on breeding seasons are indicated where possible. The new species include a number of previously unknown Proch/oron/Didenmmim symbioses, Crowded ectodermal columnar cells projecting from parts of the whole of the outer surface of adult zooids and pigmented squamous epithelium in certain species ina number of genera are reported although phylogenetic implications were not detected. Scanning electron micrographs of calcareous spicules ave presented as an identification aid to complement the dichotomous keys to taxa. Species descriptions are complemented, where possible, with in situ photographs. An annotated glossary is included, The characters of species reported from adjacent areas (¢.g. the western Indian Ocean, Indonesia, Malaysiaand other western Pacific tropical locations to Fijr, as. well as New Zealand), but not yet from Australian waters, are summatised and compared, 9 Indo-Wesr Pacific. Prochloron symbioses, tropical. temperate, columnar epithelium, squamous epithelium, Patricia Kon, Queensland Museum, PO Box 330), South Brisbane 4101, Australia; 6 October 2000. CONTENTS INTRODUCTION ......5.52.2525- » Wf LISTOF TAXA 2. jb 2 ACKNOWLEDGEMENTS 2... .0..,....5 PROCEDURES, 0.5 baht 6 ee nk cee ese 6 DIDEMNIDAE Giard, 1872... 0.000000. 6 ANNOTATED GLOSSARY... .-,.5..-+ § TAXONOMY... 2s ce eee es 19 LITERATURE CITED. ............. 350 SPICULE ATLAS (Figs 157-178)... ....- 357 PLAT RS eo 5 oe ole ee eee te STH MSO eed ee eee oe ea 40) INTRODUCTION Species of the single family Didemnidae (Class Aseidiacea), one of 14 in the suborder Aplousoranchia, comprise a major component of the filter feeding communities in sublittoral locations, especially in tropical waters. where their almost two-dimensional growth pattern and rapid rate of replication ensure that they occupy much of the available substrate. Their diversity in Australia far exceeds that in other parts of the world, possibly because of radiation of species from the western Pacific and their isolation around the southern parts of the continent where the majority of indigenous species occur. The bo TABLE 1. List of Taxa — The formal page citations for new taxa erected in this work are indicated in this list, although a taxon may be informally referred to in preceding pages. Atriolum Kott, 1983, 19 A, bucinum sp. nov., 21 A, eversum sp. nov., 22 A. lilium sp. nov., 24 A. marinense sp. nov., 25 A. robustum Kott, 1983, 27 A, tubiporum sp, nov., 29 Leptoclinides Bjetkan, 1905, 31 L, aciculus sp. nov., 37 albamaculatus sp. noy., 38 brandi sp. nov., 40 caelestis sp, nov., 42 carduus sp. nov., 43 cavernosus sp. nov., 44 coelenteratus (Kott, 1962), 46 comitus sp. nov., 48 compactus sp. noy., 49 confirmatus sp. nov., 50 constellatus sp, noy., 51 . cuspidatus (Sluiter, 1909), 52 . dubius (Sluiter, 1909), 54 durus sp. nov., 57 . echinus sp. nov., 59 erinaceus sp. nov., 61 exiguus sp. noy., 62 fungiformis Kott, 1972b, 63 imperfectus (Kott, 1962), 65 kingi Michaelsen, 1930, 67 levitatus sp. nov., 69 lissus Hastings, 1931, 70 longicollis sp. nov., 70 maculatus sp. nov,, 72 magnistellus sp, nov., 73 multilobatus Kott, 1954, 74 placidus sp, noy., 75 rigidus sp. nov., 77 rufus (Sluiter, 1909), 79 seminudus sp. nov., 82 sulawesii F, & C, Monniot, 1996, 83 umbrosus sp. nov., 83 variegatus sp. novy., 86 volvus Kott, 1975, 87 Polysyacraton Nott, 1892, 89 P. arafurensis Tokioka, 1952, 93 P. circulum Kott, 1962, 94 P. dentatum sp. nov., 96 P. discoides Kott, 1962, 98 P. dramide sp. nov., 99 P. echinatum sp. nov., 101 P. flammeum sp, nov., 103 P. glaucum sp. nov., 104 P. infundibulum sp. nov., 106 P. jugosum (Herdman & Riddell, 1913), 106 P. lodix sp. noy., 108 P. magnetae Hastings, 1931, 109 P. meandratum C, & F, Monniot, 1987, 111 P. millepore Vasseur, 1968, 113 P, multiforme sp. nov., 114 P. oceanium sp. nov., 115 P. orbiculum Kott, 1962, 117 P. otuetue C, & F. Monniot, 1987, 118 P. palliolum sp. noy., 118 P. papyrus sp. noy., 120 P. pedunculatum sp. nov., 121 P. pontoniae C, & F, Monniot, 1987, 122 P. pseudorugosum Monniot, 1993, 123 P, pulchrum sp. nov., 125 P. purou C, & F. Monniot, 1987, 126 P. regulum sp. nov., 128 P. rica sp. noy., 130 [ao aE wal tal Sal Sa “all all Soll od cal a al ad a ed a EEO ee robustum sp. nov., 130 rubitapum sp. nov,, 131 rugosum Monniot, 1993, 132 scobinum sp. noy., 134 scorteum sp. nov., 135 sideris sp. nov., 136 tasmanense sp. nov., 137 P. tegetum sp. noy., 137 P. tenuicutis sp. nov., 139 Didemnum Savigny, 1816, 140 D. albopunctatum Shuiter, 1909, 148 D. arancium sp. nov., 150 astrum sp. noy., 151 bicolor sp. noy., 152 hisectatum sp. nov., 154 caesium Slutter, 1909, 155 candidum Savigny, 1816, 157 chartaceum Sluiter, 1909, 160 clavum sp. nov., 162 complexum sp. nov., 164 crescente sp. nov., 166 cuculliferum Sluiter, 1909, 167 eygnuus sp. nov., 169 delectum sp. nov., 171 effusium sp. nov., 173 elongatum Sluiter, 1909, 173 etiolum Kott, 1982a, 175 D, flavoviride Monniot, 1995, 176 D, fragile Sluiter, 1909, 177 D. fragum sp. nov,, 179 D, fucatum Sluiter, 1909, 182 D. fuscum Sluiter, 1909, 184 D. grande (Herdman, 1886), 185 D. granulatum Tokioka, 1954, 188 D. guttatum F, & C, Monniot, 1996, 189 D. herba sp. nov., 190 D. hiopaa C, & F. Monniot, 1987, 191 D, ineanum (Herdman, 1899), 191 D. inveteratum sp. nov., 193 D, jedanense Sluiter, 1909, 194 D. jucundum sp. nov., 197 . lacertosum Monniot, 1995, 199 levitas sp, nov., 200 linatum sp. noy., 200 lissoclinum sp. nov., 202 macrosiphonicum sp. nov., 203 mantile sp. nov., 203 membranaceum Sluiter, 1909, 205 microthoracicum sp. nov., 207 D. minisculum sp. nov., 207 D. molle (Herdman, 1886), 208 D. monile sp. nov., 211 D. moseleyi (Herdman, 1886), 211 D. multispirale sp. nov., 213 D. mutabile C. & F. Monniot, 1987, 215 D. oblitum sp. nov., 215 D. ossium sp. noy., 216 D. parancium sp. nov., 218 D. patulum (Herdman, 1899), 220 D. pecten sp. nov., 220 D. pellucidum sp. nov., 222 D. perplexum sp, nov., 224 D. poecilomorpha F. & C. Monniot, 1996, 226 D. precocinum sp. nov., 228 D. psammatode (Sluiter, 1895), 229 D. roberti Michaelsen, 1930, 230 D. scopi sp. nov., 233 D. sordidum sp. nov., 234 D. spadix sp. nov., 236 D. spongioide Sluiter, 1909, 237 ae 2 ORO Be SSSSoHosHgsHgygy SESsyyyy MEMOIRS OF THE QUEENSLAND MUSEUM . stragulum sp. nov., 238 sucosum sp, nov., 240 tabulatum Sluiter, 1909, 241 ternerratum sp. nov., 242 theca sp. nov., 243 tonga (Herdman, 1886), 243 uturoa C. & F. Monniot, 1987, 244 vahatuio C, & F. Monniot, 1987, 246 verdantum sp. nov., 247 via sp. nov., 248 D. viride (Herdman, 1906), 249 D. vulgare sp. nov,, 251 bOoOBSHSDSdSSSo Trididemnum Della Valle, 1881, 252 T. amiculum sp. nov., 256 T. areolatum (Herdman, 1906), 259 T. caelatum sp. nov., 260 T. clinides Kott, 1977, 261 T. cristatum sp. nov., 262 T. erystallinum sp. nov., 263 T. cyclops Michaelsen, 1921, 264 T. discrepans Sluiter, 1909, 267 T. dispersum (Sluiter, 1909), 267 T. lapidosum sp. noy,, 270 T. miniatum Kott, 1977, 271 T. nobile sp. nov,, 272 T. nubilum Kott, 1980, 274 T. paraclinides Kott, 1982, 276 T. paracyclops Kott, 1980, 276 T. pigmentatum sp. nov., 278 T. pseudodiplosoma (Kott, 1962), 278 T. savignii (Herdman, 1886), 281 T. sibogae (Hartmeyer, 1910), 283 T. spumosum sp. nov., 286 T. tectum sp. nov., 288 T. tomarahi C. & F. Monniot, 1987, 288 T. vermiforme sp. noy., 289 Lissoclinum Verrill, 1871, 291 badium F. & C. Monniot, 1996, 296 bistratum (Sluiter, 1905a), 298 caliginosum sp. nov., 300 calveis Monniot, 1992, 301 concavum sp. noy., 303 conchylium sp. nov., 305 durabile sp. nov., 306 levitum sp. noy., 307 limosum sp. nov., 308 maculatum sp. nov., 310 multifidum (Sluiter, 1909) , 311 nebulosum F. & C. Monniot, 1996, 311 ostrearium Michaelsen, 1930, 314 patella (Gottschaldt, 1898), 315 punctatum Kott, 1977, 318 . reginum sp. noy., 319 . roseum sp, nov., 322 sente sp. noy., 323 . spongium sp, noy,, 325 . taratara C, & F. Monniot, 1987, 325 . tasmanense (Kott, 1954), 326 . timorense (Sluiter, 1909), 328 . triangulum (Sluiter, 1909), 330 . variabile sp. nov., 331 PRE RE RR EERE ERE ERE Clitella gen. nov., 332 C. nutricula sp. nov., 333 Diplosoma Macdonald, 1859, 335 D.z ferrugeum sp. noy., 337 D. listerianum (Milne-Edwards, 1841), 339 D. simile (Sluiter, 1909), 341 D. translucidum (Hartmeyer, 1909), 343 D. velatum sp. nov., 345 D. virens (Hartmeyer, 1909), 347 THE AUSTRALIAN ASCIDIACEA 4 present work is the first comprehensive study of the family in Austrian waters, OF the 202 species now recorded 116 are new and only 86 were previously known — 51 already recorded from Australia and 35 previously known only from other parts of the western Pacific. The other Aplousobranch families are discussed in the Australian Ascidiacea parts 2 and 3 (Kott, }990a:1992a) and part 1 (Katt, 1985 Y deals wath the suborders Phlebobranchia and Stolidobranchia. Additional information including new species and records in the taxa treated in parts |~3 of the Australian Ascidiacea ure discussed in supplements (Kott, 1990b:1992h), About 600 species of Ascidiacea are now known to occur in Australian waters. Much material in all suborders, including the Didemnidae remains to be examined. All specimens referred lo by a museum registration number were examined in the course of this study, Where a sample of a colony or specimen lot is lodged in a second institution its registration number is given in italics following the registration of the principal lot. Museums holding ascidian material examined during this study, with their abbreviations, are: AM, Australian Museum, Sydney; AMNH, American Museum of Natural History, New York, U.S,A,; BMNH, Natural History Museum, Londen, UK; MV, Museum of Victoria, Melbourne; NTM, Norther Territory Museum, Darwin; QM, Queensland Muscum, Brishane; SAM, South Australian Museum, Adelaide; TM, Tasmanian Museum, Hobart; WAM, Western Australian Museum, Perth; USNM, U.S. National Museum of Natural History, Smithsonian Institution, Washington D.C. USA; SM, Senckenberg Museum, Frankfurt, Germany; ZMA, Zoological Museum of Amsterdam, University of Amsterdam, The Netherlands; ZMC, Zoological Museum, University of Copenhagen, Denmark; ZMH, Zoological Museum, University of Hamburg, Germany. Photographic collections relating to this material include the Australian Marine Photographic Index (AMPI, Neville Coleman), South Australian Museum (with prefix PE, K. Gowlett Holines and others); and the Queensland Museum, Throughout this work a senior synonym is preceded by ~<" and a junior synonym by “>”, Zooids have relatively Few reliable morphological characters owiig to their small size and overall uniformity a resull of a TABLE 2. Measures of syicule ray length: be o i= = 2 2% E ae = = = eh ct 2 3 E zB & Be a Ss ° = & — =a ms — = Fs Roy lenath relative to ; . . 7 < : Jt * central spleuie 3 = iS 2 Tans disnever T 4 tea treneote| 2I= 28=| 19= os2—) ona | oe % i uo 34 . a |} diameter DA o4 33 02! add | simplification and convergence. Further, contraction often obscures significant zooid characters, (he form of colornal systems ptien arc difficult to determine, colony shape and size are affected by age, environmental factors and preservation and colours are variable and affected by oxidation and preservative, These factors have been a major constraint to accurate species definitions and determinations, which both depend to a great extent, on larval characters and spicule size and form. As in all colonial ascidians, larvae are viviparous, and in most taxa have heen found being broaded in one or more colonies, The month in which they occur has been recorded, Spicules have traditionally been defined by their size (maximum diameter) — the distanee between the points of rays on opposite sides af the sphere, and by the number of rays in optical transverse section, Rach species has spicules ofa characteristic size range. Spicules of maximum diameter occur relatively frequently (mixed with others of lesser diameter) and ure readily detected (by light of scanhibe electron microscopy) in preparations of'strips of test from 5mm long.. The maximum spicule diameter is used to define species in the keys and descriptions that follow, The significance of average or mean Values for spicule size 1s doubtfid without .an accurate assessment of standard deviations, an indication of the full range of sizes and some measure of the variations in frequency of different sized spicules. Interpretation of spicule form by light microscopy has heen subjective and is not always reliable. Scanning electron microscopy has allowed more critical interpretations of these 3-dimensional, opaque structures, A more or less pentagonal arrangement of each whorl of spicule rays has been demonstrated, making possible relatively accurate counts of the humbers of rays in a so-called optical transverse section. Also 4 MEMOIRS OF THE QUEENSLAND MUSEUM used in the present work to describe the spicules and their rays is an assessment of the ray length/spicule diameter ratio (Table 2). In the spicule atlas (Figs 157-178) similar spicules are grouped (rather than arranged in species alphabetical order) for ease of comparison. There have been few studies on the Ascidiacea in Australian waters and, probably because of the problems set out above, even fewer on the Didemnidae. Previous attempts to study the family often were unsuccessful because characters for species determination had not been identified, and in many cases similarities in the small simplified, convergent and often contracted zooids distracted attention from other characters, frustrated attempts to separate species from one another and resulted in many wrong assignations. Revision of much of the Pacific material in the Zoologische Museum (Amsterdam) and the US National Museum (Washington D.C.) has shown that Sluiter (1909), Van Name (1918) and Tokioka (1967) had similar problems in defining species parameters. Nevertheless, these works and the associated well conserved collections are the basis for more recent studies on the didemnid fauna of the tropical western Pacific. Few other authors had reported on any significant collections of didemnids in the tropical western Pacific until the past decade. The exceptions are Eldredge (1967) onthe Didemnidae of the central Pacific; Tokioka (1950, 1952, 1955, 1961, 1967, 1970) and Millar (1975) on collections containing some Didemnidae from the central to western Pacific; and Kott (1977, 1980, 1981, 1982a) on didemnids in symbiotic relationships with prokaryotic chlorophyll-containing algae which, associated with an emerging world interest in this symbiosis, were the first systematic works on large collections of exclusively didemnid ascidians from the tropical western Pacific. The species list of Didemnidae in this part of the world has increased as a result of work in New Caledonia (Monniot, 1989, 1991, 1992, 1993, 1994, 1995), French Polynesia (Monniot & Monniot, 1987) and other locations (Monniot & Monniot, 1996; Nishikawa, 1984, 1994). Monniot (1993) was surprised that none of the 8 species of Polysyncraton recorded from New Caledonia were known from other locations in the SW Pacific. She suggests this is because the collections were made by SCUBA rather than dredge or shore collecting (although this would surely have affected other genera as well as Polysyncraton). \t has been found in the present study that colonies in the intertidal rubble zone are not as large as some found subtidally, but there is no evidence that SCUBA diving is sampling a different fauna from that sampled by shore collecting at low tide. The large number of new species taken from New Caledonia and those described herein apparently reflect our ignorance of the didemnid fauna. It is not evidence of either isolation, or habitat specialisation. Most of the tropical species in this family are now known to have a wide geographic range. These studies have established some appreciation of the intraspecific variation that can be expected to occur amongst populations over wide geographic ranges in the Indo-West Pacific. Proposals of pantropical species ranges resulting from transport on ship’s hulls (Rocha & Monniot, 1993) or any other cause are speculative and the conspecificities on which these proposals are based are not confirmed by the present study. In temperate waters the didemnids of the Challenger expedition (Herdman, 1886), provide the basis for study of the family. Reports on small collections from south-western Australia (Michaelsen, 1930), New South Wales (Herdman, 1899; Kott, 1972c), southern Australia (Kott, 1972a-b, 1975, 1976) and other general collections (Kott, 1962) did not appreciably advance understanding of Didemnidae in these waters owing to the same lack of understanding of the group that beset studies in other parts of the world. Few species of the Didemnidae have a continuous range from tropical into temperate waters, such a range occuring more often in other families of Ascidiacea (see Kott, 1985, 1990a, 1992). As with other taxa, more indigenous species occur in temperate than tropical waters, although Didemnidae are more diverse in tropical waters (Kott, 1982c), reducing diversity toward the poles. Two tropical species known from Australian waters may possibly occur in New Zealand, viz. Polysyncraton fuscum (?P. meandratum) and P. paradoxum (?P. robustum). However, although possible Gondwana ascidian relicts have been recorded from Australian and New Zealand temperate locations, there are no records of didemnid species in this category (see Didemnum fragum). Kott (1998) documented 59 valid species previously recorded from Australia. Didemnum incanum, removed from synonymy and validated in the present work, should be added to the total. THE AUSTRALIAN ASCIDIACEA 4 5 Of these 60 species, D. roftnesti Kott, 1962, Polysyncraton victoriensis Kott, 1976 and D. fimbriatum Herdman, 1899 await revision and their status is uncertain. A further 6 species said to occur here result from misidentification, viz Didemnum augusti: Kott, 1962, D. lambitum: Kott, 1962; Polysyncraton mortenseni: Kott, 1954; Trididemnum cerebriforme: Kott, 1962 and 7. spiculatum Kott, 1962. ACKNOWLEDGEMENTS During this study, I have had the support of colleagues both in Australia and overseas. In particular, [ thank the successive Directors and Boards of the Queensland Museum for their continued support. I also thank Curators and Collection Managers in Australian and overseas museums for their very prompt responses to my requests for loan of specimens — in Australia Penny Berents (Australian Museum), Sue Boyd (Museum of Victoria), Loisette Marsh and Jane Fromont (Western Australian Museum) and Wolfgang Zeidler, Karen Gowlett Holmes and Thierry Laperousaz (South Australian Museum); and from overseas Joke Bleeker (Zoological Museum, Amsterdam), Sheila Halsey (the Natural History Museum, London), Hilke Ruhberg (the Zoological Museum, Hamburg) and Linda Cole (the US National Museum of Natural History, Washington D.C). I have been fortunate in the richness of the collections available to me and the comprehensive sampling of the Australian coast they represent. Much of this collecting has been by SCUBA diving, yielding mature, undamaged colonies, The Western Australian Museum (especially Shirley Slacksmith and Loisette Marsh) took material, by dredge as well as SCUBA, from all the western Australian coast including the North West Shelf. Jan Watson has extensively sampled the Victorian coast. The South Australian Museum (especially Wolfgang Zeidler, Karen Gowlett Holmes, Hugh Bavenden) and South Australian Fisheries Department (Scoresby Shepherd and his team) have sampled the Gulf St Vincent, Spencer Gulf and the Great Australian Bight. Karen Gowlett Holmes photographed samples from across the southern coast from Tasmania to Albany and from the Northern Territory. I have also had available the collection (now in the Queensland Museum) made by the Australian Institute of Marine Science (AIMS) Bioactivity Group from all around the continent, including the Kimberley coast, the Arafura Sea and the Great Barrier Reef (McCauley et al., 1993). I am grateful to the photographers who have made it possible for me to appreciate the living appearance of many of the species — especially Neville Coleman (Australian Marine Photographic Index), Karen Gowlett Holmes (South Australian Museum), Roger Steene (Cairns), Ron and Valerie Taylor (Sydney), Myriam Preker (Heron I. Research Station) and members of the AIMS Bioactivity Group. I acknowledge with particular gratitude the work of my successive research assistants both in the laboratory and in the field, John Kennedy (1991-3), Susan List (1994-6) and Daniel Schmidt (1998-2000). John Kennedy drew many of the black and white figures of Leptoclinides and Atriolum and produced the scanning electron micrographs of their spicules. Susan List and Daniel Schmidt drew the remainder of the figures and prepared and scanned spicules of more than 1000 specimens of Didemnum, Polysyncraton, Trididemnum and Lissoclinum. As well as drawing many of the figures, Daniel has revised and updated most of the others and has composed the paste ups and scanned these and the colour plates. In executing these responsibilities he has demonstrated an appreciation of the Didemnidae that has significantly advanced this work. Also, since 1980, able and enthusiastic assistance in the field has been provided, at various times, by Andrew Rozenfelds, Lucille Crevola-Gillespie, Stephen Cook, David Parry and Myriam Preker. Georgia Pass generously helped with the initial pasteups of many of the figures. Jennifer Mahoney, Audra Topping, Lynette Dickfos, Katie Laws and Jennifer Cannon successively updated the manuscript as it developed through its many drafts, and I thank them for their co-operation, diligence and good humour. I also thank Mr U. Tinggi of the Scientific Service in the Queensland Health Department, for his analysis of a sample of Atriolum robustum for vanadium. I am grateful to my colleague, Dr Lester Cannon, for sharing his wide knowledge of taxonomy and invertebrate structure and function with me over the past 20 years, Since 1980, grants from various agencies have supported the field and laboratory programme as collections were made and examined, data compiled and manuscripts prepared for this Monograph. The agencies are the Australian Biological Resources Study 1980-2; Marine 6 MEMOIRS OF THE QUEENSLAND MUSEUM Sciences and Technology Grants Scheme 1984-86 and the Australian Research Council 1991-3, 1994-6 and 1998-2000. PROCEDURES Formalin fixed, and preferably narcotised specimens are essential to adequately dissect and observe the morphology of specimens of the Ascidiacea. This is particularly true for Didemnidae, which have especially small zooids in complex systems. Long term preservation specimens should be transferred to 70% ethanol after at least 2-3 months in fixative. In all genera of this family, following observations on surface structures, a thin vertical inspection slice or wedge, through the whole depth of the colony from a common cloacal aperture to the outer margin, will display the general form of the cloacal systems, the position of the zooids, and the distribution of bladder cells, spicules and other inclusions in the test. The inspection slice is always cut parallel to the long axis of the zooids — ie. generally at right angles to the upper surface and thick enough to include whole zooids but thin enough for light microscopy. Efforts should be made not to excessively mutilate the colony. Neither didemnid nor any other ascidian colony should ever be cut horizontally (parallel to the surface), for this divides the zooids and obscures the configuration of the cloacal cavities. Zooids and embryos can be observed in situ in these inspection slices, or they can be removed for manipulation and dissection. Care needs to be taken to avoid tearing off branchial or atrial siphons when removing zooids. It usually is not possible to remove didemnid zooids entire. They invariably break across the oesophageal neck. Zooids can be dissected with sharpened needles or forceps in a drop of glycerol on a glass slide. Sometimes a drop of stain added either to the colony itself or to the slice of it, or to the zooids and embryos (after their removal) will help to display their structure. Often zooids are held so tightly in the test that they cannot be removed and it is necessary to decalcify the hand-cut section of colony in order to observe the zooid structure. Hand-cut thin sections of colony can be decalcified by dropping into an excavated block or watch glass with sufficient 3% HCI to cover the section. Generally decalcification will be completed in 1-3 hours, although often it is necessary to renew the acid owing to the buffering effect of the calcareous spicules. Leptoclinides and Atriolum have large zooids in which organs can be readily observed by dissection and manipulation, although they are not always easy to remove from the colony and are best observed in situ. In other genera the structure of small zooids can be adequately examined only in stained and cleared permanent mounts of either the isolated zooids or the hand- cut, thin, decalcified sections of the colony. Larvae also are stained and mounted for light microscopy. Spicules are prepared for SEM by incinerating a small fragment of test (to remove all organic material) on the tip of fine forceps. They are then put into a drop of absolute alcohol on the top ofan adhesive surface on the stub. The spicules separate from one another in the alcohol and settle fairly evenly before the alcohol evaporates, leaving a suitably clean surface for coating. In order to avoid ‘drowning’ the spicules, it is essential that the adhesive used does not dissolve in the alcohol — in the present study Avery ‘Spot-O-Glue’ tabs were used. In addition to the general subjective accounts of colour, many living specimens were compared (in the field) with colour charts (Ridgway 1866) to give a more precise and objective account of colour and these are indicated in the text by a superscript R (e.g., rose red “ ) Permanent slide mounts of most zooids and larvae for light microscopy, as well as photomicrographs and scanning electron microscopy stubs of spicules are in the Queensland Museum collection. Analysis for vanadium content ofa freeze dried sample of Atriolum robustum was by nitric peroxide wet digestion followed by determination with ICP-AES. Family DIDEMNIDAE Giard, 1872 The family is relatively uniform although very speciose. It is characterised. by its small zooids divided into thorax and abdomen, the former consisting of a large pharynx perforated by 3 or 4 rows of stigmata. Gonads, in the abdomen respectively dorsal or posterior to the short, vertical or ventrally flexed gut loop, consist of a small ovary with only one egg maturing at a time, and dome-shaped to spherical or oval testis, entire or subdivided, with the vas deferens either straight, or coiled around the testis. The zooids are arranged in usually extensive cloacal systems. With the exception of Diplosoma and a few species in each of the other genera except Leptoclinides and Atriolum, the test contains minute (seldom more than 0.1mm diameter and THE AUSTRALIAN ASCIDIACEA 4 7 often less than half that size), stellate, globular or burr-like, calcium carbonate (aragonite) spicules synthesised in paired lateral organs in the parietal thoracic wall. Body wall musculature is confined to the thorax, and never occurs in the abdominal wall. Usually (except in Afriolum and Lepto- clinides and a few species in other genera) a retractor muscle projects out into the test from the ventral surface of the oesophageal neck of the zooid and 2 or 3 vascular projections, each with a terminal expansion (ampulla) extend into the test from the ventral side of the pole of the gut loop. The Didemnidae have long been regarded as the most highly evolved of aplousobranch ascidians. Certainly colony organisation, and zooid size-reduction and simplification, are more advanced in this family than in others. It is possible also that integration of the colony is well advanced, a nerve complex having been demon- strated (Mackie & Singla, 1987). Nevertheless, these developments of colony and zooid do not imply direct linear evolution through the Aplousobranchia. Compelling evidence of an early origin for the Didemnidae exists in the presence, in Leptoclinides, of very large amounts of vanadium generally found in more primitive ascidians such as Ciona (Hawkins et al., 1983). Unless the Didemnidae is polyphyletic, which seems unlikely, these high concentrations of vanadium suggest that Leptoclinides is the more primitive genus, and that the evolution of other genera has been associated with loss of atrial siphons, reduction in zooid size and loss of vanadium. The related genus A/riolum has larger zooids than Leptoclinides and, like a few Leptoclinides spp., has a functional oviduct — the ovum passing from the abdomen through the oviduct to a thoracic brood pouch where it is incubated. Thus, some characters of Atrio/um are more primitive than in other Didemnidae. However, Atriolum has an undivided testis (like Didemnum). Further, although Atriolum has been found to contain vanadium it is in lower concentrations (350ppm in A. robustum) than in Leptoclinides spp. (Hawkins et al., 1983: 8,000-10,000ppm) which may indicate a Leptoclinides ancestor There are few morphological clues to phylogeny in the Didemnidae largely because of size reduction and simplification which have resulted in a preponderance of convergent characters of doubtful relevance to phylogeny. There is an apparently significant progressive reduction in zooid size from Atriolum to Leptoclinides to Trididemnum (which often retains the Leptoclinides-like atrial siphon) to Didemnum. Polysyncraton zooids are not so small, and they have Leptoclinides-like multiplicity of male follicles, relatively num- erous stigmata and a coiled vas deferens. Condition of the testes and of the vas deferens may be indicative of generic relationships, viz. a coiled vas deferens is present in Lepfoclinides and Polysyncraton (with many ¢ follicles), and Atriolum, Trididemnum and Didemnum (each with an undivided testis). The straight vas deferens of Lissoclinum, Clitella and Diplosoma may indicate another group of related species. The retractor muscle (probably associated with reduction in length of the thorax and loss of muscles from the abdomen) in 6 of the 8 genera (all except Afriolum and Leptoclinides) does not necessarily indicate a common origin . Romanov (1989) proposed that a straight vas deferens and absence of spicules are primitive features and therefore Diplosoma and related Lissoclinum are primitive. However, there is no evidence to support a primitive status for these characters. Diplosoma (the only genus consistently lacking spicules) has complex larvae with precocious blastozooids forming in the trunk and contains species with prolific repli- cation in which primary, secondary and even tertiary buds form before separation from one another. Although in Cionidae and Diazonidae regeneration of the thorax on a conserved abdomen probably is an early stage in the evolution of replication in the Aplousobranchia (Kott, 1990a), a similar process observed in Diplosoma by Romanov (1989) is more likely convergent than primitive. Larfargue (1983) proposed the linear evolution of didemnid genera from Cystodytes (Poly- citoridae), through Lissoclinum to Polysyncraton and Didemnum to Trididemnum, while Diplosomais derived from Lissoclinum by loss of spicules. Larfargue (1983) has not included Leptoclinides in her considerations, being primarily concerned with Didemnidae from the French coast. The present study suggests that a linear relationship of the genera is unlikely, and that derivation of the family (with the Diazonidae or Holozoidae) from some common ancestor is more likely than from the Polycitoridae (see discussion on Afrio/um, below). Didemnid genera are distinguished from one another by the presence or absence of spicules, condition of the testis (undivided or bisected, or divided into more than 2 follicles), course (and 8 MEMOIRS OF THE QUEENSLAND MUSEUM length) of the vas deferens (hooked proximally but otherwise straight, vertical, and relatively short; or a longer duct, its length taken up in its spiral course around the testis), presence or absence of a retractor muscle, presence or absence of an atrial siphon, and number of rows of stigmata (3 or 4). Species are distinguished from one another by zooid size (generally directly related to the number of stigmata per row), presence or absence of an anterior atrial lip (or tongue), orientation and general proportions of the gut, numbers of coils of the vas deferens, size, shape and distribution of the spicules, form of the colony and common cloacal systems and size and form of larvae. Position, shape and size of the lateral organ are affected by contraction of the thorax and are generally significant characters for species determination only within limits. ANNOTATED GLOSSARY The following entries relate specifically to the Didemnidae. They should be used in conjunction with glossaries on aspects of all families of the Ascidiacea (Kott, 1985, 1990a, 1992a), atrial apertures, — siphons: Atrial apertures are on long muscular siphons in Lepfoclinides, Atriolum and usually in Trididemnum. In other genera (excepting Didemnum fucatum which has a small circular sessile opening) the atrial aperture is a large sessile opening that exposes a large part of the perforated branchial sac directly to the cloacal cavity. In certain Didemnum, occasionally in Lissoclinum and commonly in Polvsyncraton, an anterior tongue (sometimes called a lip) projects from the anterior rim of the opening. It is muscular, and in many species in which it occurs its length is related to the position of the zooid relative to the common cloacal aperture. The tip of the atrial tongue (especially in Polvsyncraton) often is bifid and sometimes has a fringe of small papillae along its edge. It can be inserted into the test over the common cloacal cavity or it may be expanded and increase in length to extend through the roof of the common cloacal cavity into the rim of the common cloacal aperture. The zooid then has some capacity to control water pressure in the colony and in the pharynx either by closing the common cloacal aperture or by pulling the roof of the common cloacal cavity down over the common cloacal canals and over the atrial apertures. atrial lip, — tongue: see atrial aperture. blastozooids: see larvae, replication. branchial apertures, — siphons: Branchial apertures always are on cylindrical siphons which sometimes, especially in Didemnum, are particularly long. The siphons are relatively uniform, with 6, usually pointed projections or lobes around the rim of the apertures, although in some Leptoclinides the pointed lobes around the aperture are not developed. The test always projects to line the siphons, very often, with spicules which either form a plug in the siphon or appear (from the surface) to line the margin of a stellate opening. The shape of the openings appears to be determined by a stellate cross section of the lumen of the siphon, possibly caused by longitudinal muscles inserted into the branchial lobes. branchial sac: sce stigmata. colony shape: Convergence in the form of colonies is conspicuous, most genera containing representatives of the full range of shapes from small one-system cushions with a central common cloacal aperture to more extensive single or multi-system colonies. The thin sheet-like irregular colonies, containing randomly distributed common cloacal apertures are probably the most commonly encountered colony form in most genera except Atrio/um and Leptoclinides which tend to form more 3- dimensional shapes with terminal common cloacal apertures on elevated parts of lobed or irregular fleshy masses. Some species in most genera except the soft Diplosoma and Lissoclinum have finite and characteristic shapes, e.g. flask-shaped, spherical, stalked or small oval or circular cushions. Upright colonies or projecting lobes sometimes are supported by the basal test expanded up into a pillar or solid central mass, partially separated from the surface zooid-bearing layer of test by a cloacal cavity; or water pressure in a large central cloacal cavity maintains the shape of the colony. Some massive 3-dimensional colonies in Leptoclinides, Didemnum and often Trididemnum are branched or fold over and the surfaces coalesce to form 3-dimensional reticular or sponge-like structures with external surfaces and spaces as well as extensive common cloacal spaces enclosed in the colony (Leptoclinides echinus, Didemnum clavum, D. complexum, D. ossium, D. lissoclinum, D. psammatode, D. spongioide, Trididemnum crystallinum, T. lapidosum, T. nobile, T. sibogae and T. vermiforme). Many species (e.g. Lissoclinum bistratum, Didemnum molle, Diplosoma virens) lobulate and the replicates move apart, spacing themselves evenly THE AUSTRALIAN ASCIDIACEA 4 9 over the substrate (Ryland, 1990). Extensively branched tree-like structures (e.g. Didemnum ossium, D. lissoclinum, Trididenmum lapidosum) often have a hard core of packed spicules which serves as asupporting frame through the centre of each branch (see also cloacal systems; common cloacal apertures; colony surface; substrates). colony surface: The colony surface is either smooth or (less often) has surface ridges (see Didemnum spongioide) or papillae. Some species have small spicule-filled papillae on the whole or part of the surface which make it rough or raspy. A few species in Didemnum (e.g. D. cuculliferum) and occasionally Polysyncraton (P. echinatum) have a hollow spiky papilla associated with each branchial aperture which accommodates an enlarged ventral lobe of the branchial aperture. These papillae appear to protect the branchial apertures (Didemnum cuculliferum). The surface may also be raspy if spicules are crowded and/or large in the superficial layer of test, although they are not always present there, the superficial layer of test being crowded with spherical bladder cells (often mixed with pigment cells) which can create a particularly smooth surface. Many colonies, especially when preserved, have the surface marked by a mosaic of circular to oblong areas separated from one another by narrow depressions. These depressions, usually lined on each side by zooid openings, are formed by the collapse of the thin layer of test forming the roof of the primary common cloacal canals that surround solid stands of test or clumps of zooids. colour: Colours derive from pigment cells in the test, blood cells (which often diffuse into the test and symbionts in the test) or in the common cloacal cavity. All colour appears to change, probably as a result of oxidation following collection and fixation, and generally is an unreliable character for identification. A black pigment spot — endostylar pigment cap — on the anterior end of the endostyle occurs in the cyclops group of Trididemnum species and others in.the same genus. Similar spots are in the mid-dorsal line near the neural ganglion in Dip/osoma spp. (see also squamous epithelium.) common cloacal apertures: Common cloacal apertures usually are raised above the surface of a colony where the excurrent water flow is entrained by passing currents, thus keeping it separated from the smaller incurrent streams entering each branchial aperture (see Kott, 1989). Elevated common cloacal apertures are either on chimney like projections of the test, or they are FIG, 1. Common cloacal systems (diagrammatic). A, horizontal thoracic cavity; B, thoracic primary canals lined with zooids; C, deep primary canals and secondary thoracic and posterior abdominal cavities; D, sheet or cushion-like colonies with sessile common cloacal apertures and atrial siphons opening into posterior abdominal cavities (cf. Leptoclinides, Trididemum spp.); E, cones or lobes with central test core and terminal common cloacal apertures. F, clumps of zooids in terminal branches of test connectives (cf. Diplosoma spp.). 10 MEMOIRS OF THE QUEENSLAND MUSEUM terminal on elevated parts of the colony — on upright colonies or on vertical lobes or swellings caused by structural thickenings of the basal test to form an axial core of test which support the upright colony or elevations or colony lobes. Elevations also are created by pressure of the excurrent water which inflate the surface over the large common cloacal chambers (beneath the cloacal apertures). In some colonies, however, sessile common cloacal apertures are not conspicuously elevated and there is no obvious separation of incurrent and excurrent water currents except the differences in their relative strength (Kott, 1989; Polysyncraton echinatum). common cloacal cavities: Common cloacal canals or horizontal spaces are either shallow, at thoracic and/or oesophageal level; or they are deeper, extending the length of, and sometimes into posterior abdominal cavities behind, the zooids. The small zooids are embedded in test around or above cloacal canals and spaces; or the cloacal spaces penetrate the test surrounding the the zooids or penetrate into clumps of zooids separating them from one another so that (depending on the depth of the cloacal cavity) some part or the whole of their thorax, supported by a narrow ventral strip of test, is completely surrounded by cloacal space, the thoraces stretching between the surface and a thicker basal layer of test in which abdomina are embedded. Especially in Lissoclinum and Diplosoma, whole zooids or clumps of zooids stretch between the surface and basal layers of test with the abdomina embedded separately or in clumps in the test strand (Fig. 1). dispersal: see gene flow. ectodermal ampullae: see larvae. endostylar pigment cap: see colour. epidermis: see projecting columnar cells, squamous epithelium. fertilisation: Fertilisation is internal, the egg generally is fertilised in the abdomen of the zooids, through the vestigial oviduct (Burighel et al., 1986; Martinucci et al., 1988, Ryland & Bishop, 1990, 1993; Bishop & Ryland, 1991; Burighel & Martinucii, 1994a,b). The embryo passes into the test directly from the abdomen, is incubated in the test, and liberated as a free-swimming larva either through the common cloacal cavity, or directly through the surface test. Only in Atriolum Kott, 1983 and some Leptoclinides (e.g. L. brandi) does the ovum move up the oviduct into a thoracic pouch where it is fertilised and incubated. Very occasionally the embryo remains in an abdominal pouch attached to the abdomen of the zooid (Diplosoma ferrugeum). gene flow: Although some apparently indigenous species have restricted ranges, many species of the Didemnidae in tropical as well as in temperate and polar waters, have a wide geographic range despite being internally fertilised and brooding their larvae. In those species with known life histories, the free- swimming larval life is less than 20 mins (Olson, 1983) and occasionally larvae appear to begin their metamorphosis before liberation from the parent colony ( L. durus). In such cases, larval dispersal over great distances seems unlikely and gene flow probably occurs through chains of recruitment between adjacent locations. Nevertheless, larval free-swimming life may be extended when stimuli to settle are not available (e.g. open sea without shadowed undersurfaces — Berrill, 1955, or night-time — Olson, 1983), providing opportunities for alternative strategies — one for gene flow, and one for population maintenance (Kott, 1980, 1985). Another possible agent for gene flow between populations of widespread species, separated from one another by vast expanses of deep ocean (such as Fiji and other parts of the western Pacific, and Hawaii), may be transport by driftwood, the slow recruitment rate likely to be associated with such transport possibly being accommodated by longevity of the colonies (Jackson, 1986). geographic range: see gene flow. gut, gut loop: The vertical oesophageal tube, smooth and almost spherical stomach, and thick cylindrical duodenum (often expanded distally) form the descending limb of the gut loop. A posterior stomach is in the pole of the loop, and the rectum forms the ascending loop. Usually these divisions are separated from one another by constrictions, and there are no short lengths of mid-intestine between them as in other aplousobranchs (Kott, 1990a,b). The oesophagus and stomach are always to the right of the rectum. The posterior stomach is more or less oval in most genera, although in Polysyncraton it 1s a roomy organ which expands to join the rectum. The rectum may form an elbow where the posterior stomach joins it. The proximal part of the rectum is wide and in most genera is separated from a narrower upper distal part by a short length of narrow gut surrounded by tubules of the gastro-intestinal gland. In Polysyncraton the distal part of the rectum is a particularly narrow cylindrical tube. Separation of the proximal from THE AUSTRALIAN ASCIDIACEA 4 1] distal rectum is abrupt in Lissoclinum. In Clitella a prerectal chamber is constricted off from the distal rectum. The post-pyloric part of the gut loop is sometimes short, straight and vertical; or longer and flexed ventrally sometimes being more or less at right angles to the oesophagus and the long axis of the zooid. The distal (post-pyloric) part of the gut loop may be bent up against the proximal part (e.g. in Leptoclinides dubius and related species) forming a double loop. The anal border is always divided into 2 lips. haemocoel: Possible products of the haemocoel are large brown spherical cells (0.008—0.01mm diameter) observed in the larval and adult haemocoel in Didemnum parancium, D, verdantum and D. viride and (except in D. parancium) free in the test (sometimes surrounding the adult zooid). In D. fuscum and D. sordidum similar cells are in the larval haemocoel and are conspicuous around the outside of the zooids. In D, spadix and D. etiolum they have been found free in the test around the zooids but have not been observed either in the larval or adult haemocoel. Similar cells are also in the adult haemocoel of Lissoclinum badium, L. conchylium, L. durabile and L. reginum and in the test around the zooids in L. caliginosum and L. ostrearium — all species of the fragile group of Lissoclinum, larvae: Larvae are diverse. Differences occur in the accessory adhesive apparatus at the anterior end of the trunk, presence and number of blastozooids, position of the oozooid and blastozooids (if any) in the trunk, length of the tail and size of the trunk. The larval test, especially in Lissoclinum often contains inclusions of unknown affinity that appear not to be blood or test cells, or spicules. The outer cuticle of the larval test may be marked with fine striations and ornaments (Cloney, 1990), In species with obligate symbioses with plant cells, the test of the larval trunk is modified to entangle the symbiotic cells and carry them to the new generation colonies (Kott, 1982b; below). Generally the larval trunk is deep with a large yolk mass, and a vertical pharynx and gut loop. An otolith and ocellus are invariably present in the cerebral vesicle. Usually three stalked adhesive organs are in the anterior mid-line. Each has a deep axillary cone in an equally deep epidermal cup — superficially like the adhesive organs of Distaplia (Cloney, 1977). Very occasionally, apparently associated with swiftly flowing currents (Kott, 1980), there is a dramatic increase in the number of adhesive organs (e.g. 30 in Diplosoma multipapillatum Kott, 1980, 15-20 in Polysyncraton multipapillae Monniot, 1993, and 5-9 in Lissoclinum badium Monniot & Monniot, 1996). Only in Clitella which has 2 convoluted adhesive ridges in continuous grooves instead of 3 stalked conical adhesive cones in an epidermal cup is there a significant difference in the adhesive organs. There are only 2 adhesive organs in Trididemnum cyclops, Didemnum albopunctatum, D. parancium, D. poecilomorpha, and D. pitipiri Monniot & Monniot, 1987. Usually 4 conical to finger-like epidermal ampullae are along each side of the median line, although sometimes (usually in Polysyncraton and in some Jrididemnum and Didemnum) they are more numerous (up to 24 or more). Enlarged epidermal cells often form a terminal cap on each ampulla. Ectodermal ampullae are fewer in most species of Diplosoma. In Diplosoma the oozooid and blastozooids tend to be in the anterior part of the trunk associated with the adhesive array rather than in the centre of the trunk and posterior to the yolk mass as in other genera. Usually a narrow waist separates the adhesive array from the remainder of the trunk and in Diplosoma the waist tends to isolate the blastozooids from the oozooid. In Leptoclinides and Polysyncraton and sometimes in 7rididemnum and Didemnum, a (usually large) finger-like horizontal accessory ampulla projects from the larval epidermis on the left, more or less from behind the adhesive array in the vicinity of the trunk waist, and extends anteriorly in Leptoclinides and posteriorly or vertically in Didemnum, Polysyncraton and Trididemnum. In larvae of Atriolum there is some variation in these accessory ampullae. They all project anteriorly from the waist behind the lateral ampullae but A. /i/ium sp. nov. has a short rounded projection on each side, A. marinense sp. nov. has asmall short projection on the left, and 4. robustum has 3 in a vertical row on the left. The accessory ampullae may be rudimentary stolonic vessels. Such accessory horizontal ampullae have not been detected in the larvae of either Lissoclinum or Diplosoma. Series of short-stalked papillae surround the anterior of the trunk in some Lissoclinum and in Clitella, although these never appear to separate off from the larval epidermis to form vesicles as they do in Polyclinidae and Ritterellidae (Kott, 1992a). The endostyle is short and vertical. Larval pharynges in the oozooids of Atrio/um, Leptoclinides, Polysyncraton, Lissoclinum, 12 MEMOIRS OF THE QUEENSLAND MUSEUM Clitella and Diplosoma each have 4 rows of stigmata, but those of Didemnum and Trididemnum have 3. In the one species of Trididemnum in which they occur the blastozooids also have 3 rows of stigmata. In the other genera when they occur (occasionally in Didemnum, often in Polysyncraton, Lissoclinum and Diplosoma, but never in Afriolum or Leptoclinides) blastozooids have 4 rows of stigmata. In Polysyncraton, the adult organs take longer to develop than in most other genera. Larval trunks are relatively large and robust in Leptoclinides and Atriolum (about 1.0mm). Didemnum, Polysyncraton, Lissoclinum and Diplosoma with 2 or more larval blastozooids also tend to have a large trunk 0.5 — 1.0mm long. In Trididemnum pseudodiplosoma which has blastozooids (up to 7) the larval trunk is 1.2mm long. In some species without blastozooids the larval trunk is less than 0.5mm. In Clitella, with up to 7-8 blastozooids, the large antero-posteriorly flattened, disc-shaped larva is 2mm in diameter. Precocious budding to produce blastozooids before metamorphosis involves production of separate thoracic and abdominal buds from the oesophageal neck of the oozooid, apparently in the same way as in adult zooids. Most Didemnum, Leptoclinides and Diplosoma have a broad, oval larval trunk but in Trididemnum, Lissoclinum and Polysyncraton the trunk narrows posteriorly. lateral organs: Spicules have a cellular origin in the thoracic lateral organs (Lafargue & Kniprath, 1978; Ballan-Dufrangais et al., 1995) — paired ectodermal invaginations into, or spoon-shaped or flap-like projections from, the parietal body wall, one on each side of the thorax. The test projects into the concavity of the lateral organ, and when this knob of test and spicules is pulled out it can evert the concave lining of the lateral organ and it changes an inverted pocket to a stalked projection. The lateral organs are usually on each side of the base of the atrial siphon when one is present or in species with open, sessile atrial apertures the lateral organ is on the edge of each side of the opening. However its precise location varies due to contraction of parietal and pharyngeal muscles. In Atriolum and Leptoclinides the lateral organs are circular to oval saucer-like depressions in the parietal thoracic wall at each side of the base of the atrial siphon. In Atriolum they are 0.06—0.lmm diameter. In Leptoclinides most are 0.04—0.06mm diameter, although in L. cvelenteratus, L. cuspidatus, L. imperfectus, L. levitatus, L. longicollis, L. placidus, L. variegatus and L. rigidus they are about 0.1mm diameter; L. brandi to 0.125mm, L. confirmatus to 0.225mm diameter; and L. echinus to 0.3mm diameter. 7rididemnum spp. have saucer-like depressions in the parietal body wall (similar to Leptoclinides) at each side of the base of the atrial siphon, opposite the second interstigmatal vessel. They generally are 0.04—0.06mm diameter but in T. sibogae and T. lapidosum they are about 0.2mm diameter. In Polysyncraton the lateral organs are depressed into the parietal thoracic wall. They are found in the mid-thoracic wall between the first and third interstigmatal vessels and ventral to the lateral rim of the atrial aperture. Their maximum diameter is 0.04—-0.06mm and they are deep, often spherical flask-shaped organs. The narrow opening to the exterior is directed ventrally. In Didemnum, the lateral organs are ventral (each side of the endostyle). Many are large (max. diameter 0.05—0.08mm) oval to circular cup- or flask-shaped organs or pockets invaginated into the parietal thoracic wall with the opening directed ventrally; others are smaller (less than 0.05mm) spoon-shaped or simple flap-like projections from the body wall always with the concavity facing ventrally or postero-ventrally. Of the lateral organs detected, Didemnum albopunctatum, D. arancium, D, caesium, D. candidum, D. chartaceum, D. clavum, D. cuculliferum, D. grande and D. viride have invaginated flasks; Didemnum astrum, D. effusium, D. etiolum, D. fuscum, D. incanum, D. jedanense, D. membranaceum, D. minisculum , D. multispirale, D. oblitum, D. patulum, D. pellucidum, D. perplexum, D. sordidum, D. spadix, D. uturoa, D. velatum and D. vahatuio have projecting stalked spoon-shaped lateral organs; and D. crescente, D. fragum, D. jucundum and D. lissoclinum have flap-like projections. The lateral organs are opposite the first to the third interspace, but most often opposite the third row of stigmata. Lissoclinum has arange of lateral organs, from saucer-shaped invaginations 0.03— 0.125mm in diameter (the largest, L. concavum and L. sente) to spoon-shaped projections (L. badium, L. bistratum, L. conchylium, L. patella and L. ostrearium). The lateral organs in this genus are very close to the endostyle, and as in Didemnum, opposite the first to third interstigmatal vessel, usually opposite the second and third interspace or the third row of stigmata. In Clitella nutricula the lateral organ is a 0.1mm diameter saucer in THE AUSTRALIAN ASCIDIACEA 4 13 the parietal body wall opposite the fourth row of stigmata. Lateral organs were not detected in the aspicular Diplosoma. Spicules are not known in the larval test of any taxon, and, with the exception of Atriolum robustum and Didemnum fucatum, lateral organs have not been observed in the larval pharynx. lobulation: As well as replication of zooids and growth of the colonies, colonies of some species subdivide in a process known as lobulation (Cowan, 1981; Ryland et al., 1984; Ryland, 1989). This confers selective advantages and has ecological consequences associated with dispersal (Kott, 1982a). Having subdivided, the replicate colonies of certain species are known to move away from one another to space themselves. Other movements are toward the light. This movement and colony replication has been observed only in tropical Didemnum molle (see Birkeland et al., 1981; Cowan, 1981), and Lissoclinum bistratum, L. voeltzkowi ( Sigillina deerrata) and H. fantasianum (Kott, 1990a). Monniot (1989) dismissed any hypothesis of a phylogenetic relationship on the grounds that brood pouches occur in genera of other families (e.g. Pseudo- distomidae). She argues that Sigillina (and presumably Hypodistoma as well) is more closely related to Eudistoma than to other holozoid genera, that therefore the brood pouch in Sigillina occurs independently of the holozoids. She therefore concluded that a brood pouch always occurs as an independent apo- morphy. Monniot’s arguments are invalid: Sigillina and Eudistoma have little in common except 3 rows of stigmata and independently opening 6-lobed apertures. The relationship of Sigillina with the Holozoidae (rather than Polycitoridae) is based on body musculature and role of the vegetative stolon rather than the number of rows of stigmata (Kott, 1990a). Further, even though a brood pouch may have evolved independently in one or another taxon (including Afriolum), this does not mean that it is an apomorphy in all the taxa in which it occurs, The overall similarity of the zooids of Atriolum and Hypodistoma (not just the brood pouch as Monniot implies), as well as their large larvae of similar size, could be the result of convergence associated with the posterior abdominal position of the cloacal cavity in both taxa. Nevertheless, the possibility of a common ancestor for Holozoidae and Didemnidae (before the replicative stolon of the Holozoidae evolved) should not be entirely dismissed. Atriolum, like Leptoclinides, has inconspic- uous dorsal pharyngeal muscles, terminating at the posterior end of the thorax, and like Lepto- clinides it lacks a retractor muscle, and has large zooids with posteriorly directed atrial siphons. Monniot (1989) believed the brood pouch to be the sole distinction, separating Afriolum from Leptoclinides. It has, however, longer atrial siphons and a combination of other characters, some of which are in other didemnids but occur together in Afriolum. Like Trididemnum, most Didemnum and a few Leptoclinides, Atriolum has an undivided testis. Certain Leptoclinides spp. (e.g. L. coelenteratus and related species) have 5 small atrial lobes and atrial apertures opening directly into cloacal chambers as in Afriolum. However, in Leptoclinides cloacal chambers are terminal rather than central, there are secondary canals and horizontal cavities as well as the primary cavity, and the atrial siphon is shorter than in Afriolum. Also, although L. marsupialis and L. brandi have brood pouches, the embryos are incubated in the layers of basal test beneath the cloacal spaces, while in Atrio/um a single layer of test surrounding a single large central cloacal chamber contains both developing embryos and zooids. Finally Atriolum has relatively low concentrations of vanadium (350ppm), an element that is present in Leptoclinides in concentrations of 8,000 — 10,000ppm (Hawkins et al., 1983). Leptoclinides unitestis Monniot, 1989 from New Caledonia has zooids and spicules similar to those of Afriolum marinense, viz. 18 stigmata in each of its 4 rows (an unusually high number for Leptoclinides), an undivided testis, a large larva (trunk length 1.5mm), and large spicules (in the vicinity of 0.lmm diameter). Nevertheless it differs from Afriolum in having numerous cloacal apertures and only a short atrial siphon. Coelocormus Herdman, 1886 has a colony similar to Atrio/um, although its numerous male THE AUSTRALIAN ASCIDIACEA 4 21 follicles suggest that it is more likely a synonym of Leptoclinides. Leptoclinides marsupialis (Monniot, 1989) from New Caledonia, first assigned to Atriolum, differs in having the testis divided into 5-6 male follicles, cloacal canals rather than a large central cavity receiving the smooth-rimmed atrial apertures on short siphons, and embryos in brood pouches that separate from the thorax and are incubated in the basal test. The species also has fewer thoracic muscles than Atrio/um. It appears similar to L. brandi in which embryos rupture into the test from the top, rather than from the base of the abdomen, and in which there is a functional oviduct through which the ovum moves to the top of the abdomen as in Atrio/um. It is possible that the brood pouch in these species indicates a common ancestry for Leptoclinides and Atriolum, the character persisting always in Atriolum, but only occasionally in Leptoclinides. Atriolum is known only from 6 Indo-West Pacific species and only A. marinense, A. robustum and A. tubiporum are known from more than a single specimen. Gonads, including characteristic undivided testes, are known for all except A. tubiporum and A. eversum, The last 2 species are also the only ones in which thoracic brood pouches with embryos have not been observed. KEY TO SPECIES OF ATRIOLUM FROM AUSTRALIAN WATERS 1, Atrial apertures in central concavity... 2... 2... 2 Atrial apertures around outside ofcolony ... 2... . TOs Ee Carte aga ae SEN. eR” A. eversum sp. nov. Colonies consist of only one cloacalsystem. ..... . Lette fidis sy tetoe ges Thy Rk A, marinense sp. NOY. Colonies consist of several cloacal systems 3. Cloacal apertures constricted, regular, circular openings; cloacal cavitiesenclosed, . . . , A. tubiporum sp. nov. Cloacal apertures not constricted, regular, circular openings; cloacal cavities moreorlessopen. ..... 4 4. Cloacal apertures with flaringrims.........., 5 Cloacal apertures without flaringrims . . . 4. robustum 5. Spicules with long oars, rays: ray length/spicule diameter ratio>0.2. . . A. bucinum sp. nov. Spicules with short, blunt rays; ray length/spicule diameter rationot >0.2........ . A liliumsp, nov. tm Atriolum bucinum sp. nov. (Figs 5, 157D; Pl. 1A) TYPE LOCALITY. Western Australia (Houtman’s Abrolhos, Wallabi Group, coll. C.Bryce 1994, holotype QM G304670). COLONY. The large colony, about 8cm high, consists of a tall central trumpet or vase-like structure, with a central cloacal chamber flared out at the top. Two smaller but otherwise vase-like lobes, one on each side, and each a single system, branch from the central vase. Each cloacal chamber is lined by a layer of evenly but sparsely distributed spicules. Externally a layer of crowded spicules meets the lining of the cloacal cavity (with its sparse spicules) in a sharp line around the flared rim of the cloacal opening, which is turned back around the outside of the colony. Spicules are relatively sparse in the internal test. Atrial openings into the central cavity, are each marked by 5 clusters of spicules in the siphon lining. Spicules are large (to 0.1mm in diameter), with long, acutely pointed conical rays, 9-1] in optical transverse section and ray length/spicule diameter ratio about 0.25mm. The living colony is opaque red. Although the colour is lost in preservative, the colony remains opaque. ZOOIDS. Zooids are about 6mm from the tip of the long atrial siphon to the rim of the relatively short branchial siphon. A strong, branchial sphincter is present around the branchial siphon. The atrial siphon is in line with and is about the same length as, the dorsal border of the thorax. The short abdomen projecting from the posterior end of the thorax at right angles to its longitudinal axis, 1s bent up to the right of the posterior end of the thorax. Fine longitudinal muscles extend along the length of the thorax, and are crossed by transverse muscles. The circular muscles along the length of the atrial siphon are parallel to the longitudinal parietal muscles. Fourteen stigmata with rounded ends are in the anterior row, behind the wide unperforated band at the anterior end of the pharynx. Twelve stigmata are in the second, 10 in the third and 8 in the last row of the branchial sac. Wide transverse vessels alternate with the rows of stigmata. The relatively short gut loop has the usual almost spherical stomach, long duodenum, oval posterior stomach and wide rectum with a distinct proximal elbow and narrow constriction about halfway up, to which tubules of the gastro- intestinal gland are closely applied. The only available colony of this species does not have mature gonads or developing larvae. REMARKS. The large flaring rims around the common cloacal apertures resemble A. Jilium. The present species differs in its opaque, red colour, tall vase-shaped colonies with a deep rather than shallow central cavity and generally 22 MEMOIRS OF THE QUEENSLAND MUSEUM FIG, 5. Atriolum bucinum sp. nov. (QM G304670) —A, colony; B, diagrammatic vertical section through colony; C, semidiagrammatic transverse section through part of flaring everted rim of the common cloacal opening showing positions of spicules and zooids, with branchial apertures on the external surface and the atrial apertures on the everted border of the cloacal cavity; D, zooid showing long atrial siphon; E, gut loop showing gastro-intestinal gland. Scales: A, B, 1.0em; C, 1.0mm; D, 0.5mm; E, 0.2mm, larger spicules (those of A. Jilium rarely exceeding 0.06mm diameter). Atriolum eversum sp. nov. (Figs 6, 157G) TYPE LOCALITY. Western Australia (Houtmans Abrolhos, SW of Split I., Morning Reef, Wallabi Group, 180m, coll. L. Marsh 10.4.78, holotype WAM 366.80). COLONY. The colony, a firm, upright, laterally compressed cup with a smooth, even surface, is 2cm long and about Icm high. A concavity about 0.5 cm deep extends along the length of the upper surface. Spicules are up to 0.1mm diameter, with sharply pointed conical rays, and crowded throughout the test. Six-lobed branchial apertures are in dimples in the test lining the upper cavity. Conspicuous atrial apertures are around the outer surface of the colony, a double row of spicules projecting into the opening alternating with 5 narrow, pointed tongues around the rim of each. ZOOIDS. Zooids are relatively large, the thorax about 3mm long, and the abdomen much less. Short but robust branchial siphons have conspicuous and sharply pointed lobes. Long (at least 2mm) posteriorly oriented atrial siphons stretch across to the outer surface of the colony. Of about 16 longitudinal muscles that terminate at the posterior end of the thorax, approximately 10 extend from the branchial siphon and the others extend across the dorsal surface behind the THE AUSTRALIAN ASCIDIACEA 4 tod ha FIG. 6. Atriolum eversum sp. nov. (WAM 366.80)—A, colony; B, semidiagrammatic vertical section through colony; C, spicules m test over the branchial lobes and in the siphonal lining; D, whole zooid. Scales: A, 5mm; B, 1.0mm; C, D, 0.5mm, neural complex anterior to the base of the atrial siphon. The latter are the proximal bands in the series of parallel circular muscles that surround the atrial siphon. Sphincter muscles surround the base of the branchial siphon and the distal tip of the atrial siphon (just behind the lobes on the rim of the aperture). The conspicuous neural com- plex, consists of a spherical ganglion and a short curved duct from the neural gland on its ventral surface to a sumple opening into the pharynx. A small lateral organ is opposite the posterior row of stigmata each side of the base of the atrial siphon. About 12 long branchial tentacles are at the base of the branchial siphon. 23 long fusiform stigmata pointed at each end are in each of the 4 rows. The long, pointed dorsal Janguets are on the transverse vessels to the left of the dorsal mid-line. The narrow gut loop is almost vertical in some specimens, although in others it is open and bent ventrally, A post-pyloric duodenal area with a rounded, bulbous distal end opens into an oval posterior stomach, The gut abruptly increases in diameter at the proximal end of the rectum (in the pole of the gut loop). A conspicuous constriction is halfway up the ascending limb of the gut loop, Where it is surrounded by tubules of the gastro-intestinal gland. The bilabiate anal aperture opens into the base of the atrial cavity. Gonads and larvae are not known. REMARKS. The cloacal system appears to have developed a stage beyond that in other species of Arriolum, the atrial apertures opening around the outer surface rather than in an internal cayity or a concavity on the upper surface. It1s as if the more usual closed cloacal cavity (as in 4. marinense and A, robustim) was opened to the surface (as in A. Lilium), and the whole colony subsequently turned inside out to achieve this colony form in which the oral surface has become concave and 24 MEMOIRS OF THE QUEENSLAND MUSEUM enclosed and the excurrent pores are on the outer surface (Fig. 6). Apart from differences in the cloacal system this species resembles others in this genus, with particularly large zooids and long, narrow atrial siphons with conspicuous 5-lobed apertures. It has more stigmata and larger spicules than other species in the genus. Atriolum lilium sp. nov. (Figs 7,157B; Pl. 1B) TYPE LOCALITY. South Australia (eastern Great Australian Bight, Flinders L, Investigator Group, in caves with predatory cymatid mollusc, coll. N. Holmes Photo Index PE0036 R951 10.4.83, holotype QM GH2385). FURTHER RECORDS. Indian Ocean (Great Australian Bight 33°14.5°S 126°20°E 183-192m, coll. El Tanin statn 2276, USNM 16406). COLONY. The tough, robust holotype, about 5em long has 2 large, concavities along the upper surface, each reminiscent of the inside of an open lily and homologous with a cloacal chamber. A conspicuous bladder cell layer is not present on the external surface, and a distinct line or rim is around each concavity where its test lining with evenly but sparsely distributed spicules meets the spicule-crowded surface test of the remainder of the colony. Only few scattered spicules are in the slightly translucent internal test. The lining of each concavity is pierced by 5-lobed atrial apertures, with double rows of spicules continuing into the siphonal lining between the lobes. Six-lobed branchial apertures open to the exterior around the external surface, being absent only where a few short stumpy attachment processes, which appear to have raised the colony above the substrate, project from the under surface. As in all species of this genus the zooids stretch between atrial apertures into the internal chamber and branchial apertures on the outer surface of the colony. Stellate spicules with 11 to 13 conical rays in optical transverse section and ray length/spicule diameter ratio from 0.15 to 0.2 are up to 0.1mm diameter, although the majority are only about half that size. ZOOIDS. Zooids, relatively small for this genus, have a thorax about 1.5mm long, and a slightly shorter abdomen. A very long atrial aperture reaches to open by its 5-lobed aperture into a concavity on the upper surface. Branchial apertures have 6 sharply pointed lobes. Longitudinal muscles extend the length of the thorax, circular muscles with a sphincter at its tip surround the atrial siphon. A sphincter muscle also is present at the base of the branchial siphon. The dorsal ganglion is conspicuous, and a short curved neural duct opens into the pharynx by a simple opening. Large triangular dorsal languets are on the transverse vessels to the left of the mid-line. About 14 stigmata are in each of the 4 rows in the branchial sac. The abdomen, bent up alongside the thorax has an open gut loop with the post-pyloric part bent ventrally. Occasionally, in this specimen, it is a tight, straight loop. The stomach is large, and a short, thick, cylindrical duodenum is separated from a small oval posterior stomach by a constriction. The wide rectum is also sharply constricted off from the distal end of the posterior stomach. Branching tubules of the gastric gland cluster around the ascending limb of the gut loop about halfway up the rectum. Gonads are in the holotype. The testis is entire and is surrounded by 4 coils of the vas deferens spiraling in a clockwise direction in all the examined zooids. The testis is mature and obscured by a large ovum, with a conspicuous oviduct. Embryos, in brood pouches constricted off from the thorax near its posterior margin at the base of the atrial siphon, are against the wall of the cloacal cavity, into which they probably are liberated. The larval trunk, 1.0mm long, with the tail wound two-thirds of the way around it, has 4 large, rounded lateral ampullae along each side of the 3 large relatively short stalked antero-median adhesive organs. On each side, a short, rounded accessory ampulla projects forward from the larval waist at the base of the lateral ampullae. A small ocellus and an otolith are in the cerebral vesicle, and 4 rows of stigmata have 11 stigmata in the anterior row and the numbers in each row progressively reduced to 8 in the posterior row. REMARKS. The species is distinguished by its large open, flaring cloacal apertures, large size range of spicules and relatively small zooids with fewer stigmata than most other species. The shape of the spicules, attachment processes from the base of the colony, long atrial siphons with 5-lobed apertures, thoracic brood pouch and single male follicle are characteristic of the genus. The species most closely resembles A. bucinum and A, robustum, having several cloacal systems in each colony — a character that readily distinguishes it from A. marinense and A. THE AUSTRALIAN ASCIDIACEA 4 25 SRA wT) ' Atty 1 HM AAT | I) : WAV A ( A tt ih ; Ht NWO y tise Hy FIG. 7. Atriolum Lilium sp. nov. (QM GH2385)— A, colony (from above) showing flaring apertures of shallow, open, common cloacal cavities; B, thorax, C, gut loop from right side showing elbow on rectum; D, gut loop from lefi side and gonads; E, larva. Scales. A, 1.0em; B-E, 0.2mm. eversum, Atriolum rahusnin has large cloacal Atriolum marinense sp. nov. apertures, but these do not flare out as in the (Figs 8, 157E,P; Pl. 1C) resent species. Further, 4. robustiuni has much Atriolum rabustin: Millar, 1Y88: $30; Monniot, 1989: 676; P P Monniot et al., 1991; 106. longer (to 5.0mm) zooids and lacks the large =? Drédemmum molle: Bachmann ¢t al., 1985; 1211 (part, } . i ecimens wil symbii from 40m). (0.1mm diameter) spicules. Atriolum bucinum Sith i ss a drs m) ar 1 4 4 : ‘PE LOCALITY. Coral Sea (Marion Reef, 8m, coll. has taller colonies that are opaque and bright ted yy Gofeman 24.8.77 AMPL 208, syntypes QM G301616). in life and its spicules have longer and more PREVIOUSLY RECORDED, Coral Sea (Chesterfield pointed rays, Reef— Monniot, 1989). New Caledonia (Monniot, 1989). 26 MEMOIRS OF THE QUEENSLAND MUSEUM West Indian Ocean (Mozambique Channel — USNM 018451 Millar, 1988). COLONY. Colonies are small (about lcm high), firm, spherical to oval, upright flasks with a sessile apical cloacal aperture. Branchial apertures open about 0.5mm apart all around the outer surface. Short, stumpy attachment processes develop from a small area in the middle of the under surface. The colonies appear to subdivide as in D. molle (below), as one specimen in the syntype lot has 2 cloacal apertures on the upper surface and a slight vertical constriction around the colony, suggesting a subsequent division into 2 upright flasks. Another is two separate flasks with their adjacent surfaces joined to one another by narrow commissures of test. The other specimen is a single flask. Basically there is only a single system per colony in this species, more than one probably being an indication of imminent colony subdivision. The outer wall of the colonies are hard and firm, and the whole colony is relatively rigid. Usually, symbiotic plant cells are present on parts of the surface in what appears to be a non-obligate relationship. Collector’s notes (N. Coleman, 24.8.77) refer to the types as pink, although in photographs (AMPI 208) they appear to be cream (see also Monniot et al., 1991). Spicules are in a thick, crowded layer in the surface. Another less crowded, thin layer of spicules lines the large, central cloacal cavity. Five-lobed atrial openings into the cloacal cavity are conspicuous, with 5 double rows of spicules outlining the lobes. The spicules are small, mostly up to 0.03mm in diameter although a few are as much as 0.04mm. They have 12 —15 long, club-shaped, pointed to blunt-tipped rays in optical transverse section, although some of the smaller ones have short conical rays. Some, when broken apart, are found to be hollow. They break up readily, and do not stay entire when attempts are made to prepare them for scanning electron microscopy. ZOOIDS. These are 2 —3mm long, stretched between the branchial apertures on the outer surface and atrial apertures opening directly into the large internal cloacal cavity. The dorsum of the thorax extends out into the long atrial siphon. Thoraces are orange when first preserved but later lose their colour. Longitudinal muscles run the length of the thorax, the ventral ones from the branchial aperture. Others dorsal to them cross the dorsal mid-line and form a continuous series FIG. 8, Atriolum marinense sp. nov. (QM G301616) — A, colony lateral view showing terminal common cloacal surrounded by branchial apertures; B, zooid; C, larva; D, anterior part of metamorphosing larval trunk showing enlarged epidermal cells on the tip of each lateral ampulla. Scales: A, 5mm; B, 0.5mm; C,D, 0.1mm. THE AUSTRALIAN ASCIDIACEA 4 with the circular muscles on the atrial siphon. Sphincters are around the base of the branchial aperture and around the rim of the atrial aperture. Up to 20 oval stigmata may be in the anterior of the 4 rows of the branchial sac, but this could not be accurately determined because of the contracted thoraces. A deep lateral organ is half-way across the thorax, level with the last row of stigmata. When everted it has a narrow stalk. A relatively short gut loop, has a thick duodenum constricted off from the oval posterior stomach; the gut increases in diameter abruptly (into a wide rectum) in the pole of the loop. Mature male and female gonads are present together in zooids of the syntypes and embryos are being incubated in brood pouches. These separate from the zooids and lie free in the test when embryos become tailed larvae. The testis is undivided and has 7 coils of the vas deferens. The large ovum apparently moves up the oviduct to the thoracic brood pouch. Thoraces, abdomina and brood pouches all lie at the same level in the wall of the colony, the abdomen to the left and the brood pouch to the right of the dorsal mid-line of the thorax. The larval trunk is about Imm long. The 3 antero-median adhesive organs have long narrow stalks. Four ectodermal ampullae are on each side of the body, and a small accessory ampulla process projects forward from the top of the larval waist on the left. Four rows of about 12 stigmata are in the larval pharynx and a large otolith and ocellus in the cerebral vesicle. REMARKS. This species is readily distinguished from A. robustum by its colony and smaller zooids (which are larger than those of 4. lilium). The spicules are a similar size to those of A, robustum, but have fewer, longer and more rod-like rays with rounded tips, rather than the short conical rays of most other species of this genus. The only other species in which hollow spicules have been detected is Polysyncraton circulum (below). Monniot (1989) reported symbiotic algae in this species. Although she did not indicate their location, it is most likely that they were on the outer surface as they are in the newly recorded colony. The rose colour of the New Caledonian specimens when first preserved apparently is the same as the pink recorded for the living syntypes. Specimens from the Mozambique Channel assigned to A. robustum by Millar (1988) were reported to ‘agree closely with Kott’s account’ (Millar, 1988: 8). This is true of the zooids, but re-examinaton of these specimens (USNM 018451) show the colonies to be the regular vase-shape of A. marinense rather than the massive, irregular colonies of A. robustum; and to have spicules characteristic of the former species — i.e. smaller than those of A. robustum. Monniot’s (1989) contention that flask-shaped specimens from New Caledonia (of which she had photographs of living material) agreed well with Kott’s (1983) description of A. robustum is even more difficult to understand. Indeed neither the description (Kott, 1983) of A. robustum nor the irregular type specimens are anything like the regular vase-shaped colonies of the present species, to which the New Caledonian material belongs. Atriolum robustum Kott, 1983 (Figs 9, 157A; Pl. 1D) Atriolum robustum Kott, 1983: 13, 1998: 80. Not Atriolum robustum: Millar, 1988: 830, Monniot, 1989; 676. Monniot et al., 1991; 106 (<4. marinense). NEW RECORDS. Queensland (Swain Reefs, QM G305675). PREVIOUSLY RECORDED, Queensland (Swain Reefs — QM GH 1410 Kott, 1983; Raine I. - QM GH286 Kott, 1983). Torres Strait (Murray |—QM GH285 holotype Kott, 1983). COLONY. The tough, irregular colony is tuber- shaped with short, tapering attachment processes projecting from its base. These probably support the colony off the substrate — they appear to be strong, rigid with pebbles attached at their narrow distal ends. Some large, rounded swellings up to 3cm diameter are along the upper surface, each with a central common cloacal aperture. Despite Kott’s (1983) comment that these are numerous, there are only 2 in the holotype. They are more numerous in QM GH286. Common cloacal apertures are sessile, and of varying sizes, some large and half everted exposing some of the internal lining of the cavity to the exterior. The large cloacal cavity extends through the centre of the colony, expanding into large chambers beneath each cloacal aperture. In life, the colony is said to be firm and tough, but gelatinous, and greenish-grey with orange-vermilion zooids, but beige translucent in preservative. The surface is firm, and in long-preserved specimens the test glassy. It always is very tough. Spicules are present only in the surface layer (where they are moderately crowded only around the branchial apertures, which appear as white points in the surface of the colony) and in the layer lining the large, central common cloacal cavity (where they are only sparse). Branchial apertures open all 28 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 9, Atrioliun vobustum (A.F,G, QM GH285; B, OM G305675; CE, QM GH286; D, QM GHI410)— A-D, colonies; E, distribution of spicules in surface test over branchial lobes; F, zooid; G, larva. Scales: A-D, 1.0em: E,G, 0.2mm; F, 0.5mm. THE AUSTRALIAN ASCIDIACEA 4 over the surface, even on the under surface between the attachment processes. Spicules also form white opaque points where they line the 5 lobes of the atrial apertures opening directly into the cloacal cavity. Spicules, up to 0.04mm in diameter are stellate with up to 18 short conical rays in optical transverse section. There is no conspicuous bladder cell layer in the surface test. ZOOIDS. Zooids are the largest for any didemnid, being about 5mm long (thorax and abdomen together). The abdomen is bent up almost perpendicular to the longitudinal line of the thorax. The postero-dorsal part of the thorax is drawn out into a long atrial siphon, the line between the branchial and atrial apertures along the atrial siphon being almost a straight one stretched between the outer surface and cloacal cavity of colony. The thorax has the usual ventral longitudinal muscles extending from the branchial siphon to the posterior end of the thorax. More dorsal muscles extend across the dorsal border of the thorax and the base of the atrial siphon. Circular muscle bands along the length of the atrial siphon have branches that join them to adjacent bands and form a mesh along the length of the siphon. There are sphincters around the tip of the atrial siphon and along the length of the branchial siphon. The dorsal ganglion is conspicuous. A curved neural duct opens directly into the pharynx. Pointed dorsal languets are on the transverse vessels, to the left of the dorsal mid-line. Stigmata are long, rectangular and up to 20 per row. A lateral organ is level with the centre of the last row of stigmata. A brood pouch is attached to the posterior side of the base of the atrial siphon by anarrow neck. The distal tip of the oviduct is diverted into this brood pouch where one ovum at a time appears to be fertilised and is incubated. The gut loop has an almost spherical stomach, thick duodenum constricted off from an oval posterior stomach, and rectum expanding abruptly in the pole of the loop. The single undivided male follicle has the vas deferens coiled 6 times around its outer surface. The coiling is sometimes clockwise, sometimes anticlockwise, and sometimes the vas deferens loops back to change direction about halfway along its course. Well developed larvae are in the holotype from Torres Strait and in the Raine I. specimen. These have a larval trunk about 1.2mm long. The 3 median adhesive organs have narrow stalks and shallow epidermal cups surrounding axillary cones constricted at their base. Nineteen stigmata are in the anterior of the 4 rows, and 16 are in the last. A large circular lateral organ is invaginated into the parietal body wall on each side of the larval pharynx. A large ocellus and an otolith are in the cerebral vesicle. Four ectodermal ampullae are along each side of the 3 antero-median adhesive organs and, on the left, 3 or 4 small accessory ampullae are in a vertical row projecting forwards from the larval waist at the base of the primary ones. REMARKS. The small spicules are more or less the same size as those of A. marinense but have conical rather than club-shaped rays. They are similar to, but smaller than those of A. /ilium and A. tubiporum and with more rays. This species is distinguished by having larger colonies, zooids and larvae than other known species. Itresembles A. lilium in its large and irregular colonies with several cloacal systems. However, although its cloacal apertures often are wide they do not expose the whole of the cloacal cavity as they do in A. lilium. The large lateral organ in the larval thorax is an unusual feature, shared only with Didemnum fucatum. Vanadium at 350ppm was contained in a small sample of QM G305675. Atriolum tubiporum sp. nov. (Figs 10, 157C; Pl. 1E) Askonides coelenteratus Kott, 1962:292 (part, specimen from Green Pools) TYPE LOCALITY. Western Australia (Albany Harbour, bay at western end of Breaksea I. Albany, 20m, coll. AIMS Bioactivity Group Q66C-2858 25.3.89, holotype QM G302885). FURTHER RECORDS. Western Australia (off Dongara, 29°50’S, 114°24’E, 128-130m, coll. CSIRO Cruise DM6, statn 214, 11.10.63 QM G302293); Green Pools, AMY 1346 Kott, 1962. COLONY. Colonies are firm, thick tubes or cylinders to about lcm diameter and lcm long from thick, sometimes branched basal stalks up to 2cm or more long. Cloacal apertures are terminal, regular and circular, in the centre of the free end of each cylinder. Occasional cloacal apertures, probably from newly developing systems are at the base of the lobes, or on the common stalks. Photographs show that in life the cloacal apertures expand to the full diameter of each cylinder so that it is open at the top. Branchial apertures which appear as dimples in preserved material are evenly distributed over the outer surface of the colony and have spicules in the siphonal lining. The atrial openings into the 30) MEMOIRS OF THE QUEENSLAND MUSEUM FIG, 10, Atriolum ubiporum sp. nov. (A,B,D—G, OM G302885; C, AM Y1346)—A,B. portions of large colony; C, small colony; D, spicules in siphon linings seen from the surface; F, semidiagrammatic section through the colony wall cutting through zooids stretched between external and internal surfaces, the branchial apertures on the outer surface and atrial apertures in the central cloacal cavity; F, thorax showing long atrial siphon; G, gut loop. Seales; A-C, 5.0mm; D, 0.5mm: E, 1.0mm; F.G, 0.2mm. central cloacal cavity are conspicuous, having 5 clumps of spicules in each siphonal lining. Spicules are evenly distributed in a thin layer in the surface and in the test lining the cloacal cavity, and are relatively sparse throughout the remainder of the test. They are stellate to 0.08mm diameter mostly with about 11 short conical rays in optical transverse section. Also, occasional spicules have about 7-9 more pronounced and acutely pointed rays. The colour of living specimens is white and cream; but they are cream in preservative, ZOOIDS. Zooids are large, to 3mm between branchial and posteriorly oriented airial aperture. Abdomina are bent ventrally from the long axis that passes through the branchial siphon, pharynx and atrial siphon between the outer surface of the colony to the central cloacal cavity. The rim of the branchial aperture is divided into 6 lobes, and 5 small pointed projections are around the rim of THE AUSTRALIAN ASCIDIACEA 4 31 the atrial aperture. The atrial siphon is about twice the length of the abdomen, and is surrounded by circular muscles that branch and anastomose with one another along its length. Longitudinal muscles extend along the thorax, and transverse muscles are in both the parietal body wall and the interstigmatal transverse bars. Thoraces are roomy, with perhaps 12 long stigmata (rounded at each end) per row, but these were hard to count owing to contraction. There are large (about 0.089mm diameter) plate-like lateral organs each side of the thorax, about opposite the third row of stigmata. Abdomina are relatively short, half their length occupied by the oesophageal neck. The simple, straight gut loop has a rounded stomach, and short rounded post-pyloric loop. The oviduct is expanded at the top of the oesophageal neck, but in these specimens there is no developed brood pouch, nor are the gonads developed. REMARKS. Although gonads are not present, these colonies have been assigned to Atriolum rather than Leptoclinides on the basis of their large central common cloacal cavities, large, circular common cloacal apertures that resemble those of 4A. marinense, long muscular atrial siphons, and large zooids with transverse muscles in the body wall. The species resembles A, robustum, but it has larger spicules with fewer rays and narrow tube-like cylindrical lobes. The species also resembles Leptoclinides coelenteratus which has less regularly cylindrical colony lobes, shallower common cloacal cavities not confined to primary central cavities, shorter atrial siphons; and smaller spicules with more acutely pointed rays. Spicules of the specimen from off Dongara (Western Australia), preserved in neutralised formalin, were soft but distinguishable and were found concentrated around the zooid openings when first examined in 1976, Although trans- ferred out of formalin at that time, the spicules had disappeared altogether when this specimen was re-examined in 1993, The colony is flask- shaped, and the test is firm and gelatinous. Leptoclinides marsupialis (Monniot, 1989) is also similar to the present species but lacks the generic characters of Atrio/um — it does not have the long posteriorly directed atrial siphon, and its common cloacal system is not confined to the single central chamber of the present species. Further, its test is brittle and packed with spicules. Genus Leptoclinides Bjerkan, 1905 TYPE SPECIES. Leptoclinides faroensis Bjerkan, 1905. The genus has large, robust colonies with generally large posterior abdominal cloacal chambers, relatively large zooids, posteriorly oriented atrial apertures on relatively long siphons, conspicuous parallel longitudinal (but rarely transverse) muscles in the parietal body wall, coiled vas deferens, and large larvae usually incubated in the basal layer of test. Dorsal pharyngeal muscles are particularly delicate consisting of 3-4 fibres, longitudinal parietal bands terminate at the posterior end of the thorax (rather than joining the dorsal pharyngeal muscle bands ventral to the oesophagus to form a retractor muscle). In most species, zooids are not readily removed from the test. Columnar ectodermal cells have been detected projecting from the body wall in relatively few species. Branchial lobes often are not developed and when present are invariably short. The rim of the atrial aperture often has 5 small pointed projections around it. The atrial sphincter usually is short and confined to the distal part of the siphon. Most species have large, stellate spicules with conical rays sometimes pointed, but often chisel-shaped or with a truncated flattened tip. Burr-shaped and globular spicules also occur. A large lateral organ is on each side of the thorax near the posterior end of the branchial sac (on each side of the base of the atrial siphon). The short gut loop in Leptoclinides has a smooth pear-shaped stomach, a thick and long duodenum, a short oval posterior stomach, and a wide rectum that expands abruptly from a constriction at the distal end of the posterior stomach in the pole of the gut loop. The rectum constitutes the whole of the ascending limb of the gut loop and has a constriction surrounded by tubules of the gastro-intestinal gland halfway up. Testis follicles usually are numerous, but in a few species (including the type) the testis is undivided. Larvae are relatively large (some- times more than 1.0mm), and usually have 2-4 lateral ampullae per side, although occasionally there are 6-8. The oozooid has 4 rows of stigmata and generally the adult organs are well advanced. Larval blastozooids do not occur. Leptoclinides spp. have been found to contain large amounts of vanadium, an element which, apart from a small amount detected in Afriolum robustum, has not been detected in other genera of this family (Hawkins et al., 1983). Its presence suggests a primitive phylogenetic position. It is 37 MEMOIRS OF THE QUEENSLAND MUSEUM assumed here that the multiplicity of male follicles also indicates an ancestral position for this genus, as does the relatively large size of the zovids and the presence of an atrial siphon, Leptoclinides is readily distinguished from most other genera of the fami ly by a combination of characters rather than any one character, The chisel-shaped tips of spicule-rays found in many species of this genus occur only occusionally in other genera. 47riolunm has larger zooids, larger alrial siphons with strong circular muscles along their whole length, transverse muscles in the parietal body wall, and colonies with a large uninterrupted ventral cloaeal cavity surrounded by a single layer of test containing zooids and embryos, rather than the extensive 3-dimensional spaces of Leploclinides. With the exception ofthe large uninterrupted cloacal cavity beneath the cloacal apertures, the common cloacal cavity in Leptoclinides is interrupted by connectives between basal and surface layers of test and the zooids are in the surface, while embryos are incubated in the basal test. Trididemnunt resembles Lepioelinides in otten (but not always) having a posteriorly oriented atrial siphon and posterior abdominal cloacal cavily, and often (but not always) large larvae, with only 3 or 4 long ampullae per side, a pronounced waist between (he adhesive array and the rest of the larval trunk and usually lacks larval blastozooids. However, its zooids are smaller than in Leptoclinides, with a retractor muscle, and only 3 rows of stigmata in adult zooids and oozooids. Included here as a synonym of Lepractinides, 1s Axskoanides Kou, 1962. The genus was distinguished by the large cloacal chambers into which zouids opened directly, and the 5 lobes on the rim of each atrial aperture. Both those characters ure present in Leptoc/inides sometimes, and in dirielwm always, In Leptoclinides the abscence of the atrial lobes appears lo be associated with a reduction in zooid size but, often they have been overlooked, sometimes because they are small, and some- times because siphons are difficult to remove entire from the test. The very large cloacal chambers with zooids opening directly into them in species formerly assigned to Askonides appear to be homologues of the large terminal chambers that are part of the three dimensional systems of Leptactinides spp. rather than homologues of the large central cavity of Asriolum. Coelocormus hudley) Herdman, 1886, known from o single specimen taken olf the coast of Patagonia, also shares some characters with Leptoclinides although it is not impossible that it is a species of Atriolum, It is a vase-shaped colony, about 3cm Jong, which Herdman thought to have been unattached. He reports a cloacal aperture in the base of the central cavity of the vase. With 5-lobed branchial apertures opening around the inside lining of the cavity, These actually may be atrial apertures, which are characteristically S-lobed in all drieltint and many Leptoclinides. Merdman’s (1886, pl, 37, fig, 3) section through the colony (vase) wall, showing zooids stretched between the outside and inner surtiaees tends to support the view that it is aspecies of Atrio/um. As in Atriolum, there do ot appear to be any secondary cavities. However, in C. huxlevi the vas deferens coils around several pyriform male follicles, and large tailed embryos are bemg incubated in the basal test which suggests) Leptoclinides (similar to L. coelenteratus) rather than Atriolum. Leptoclinides glauerti Michaelsen, 1934), from Shark Bay, Western Australia, is said to lack a cloacal cavity. the atrial apertures opening through the base of the colony, and the branchial apertures on the upper surface. The dorsal border of the thorax is stretched between the upper and lower surfaces of the colony. Michaelsen's (1930) speculative evolutionary pathway to this. colony form involves the opening up of the cloacal cavity to the exterior. Indeed, this appears to have occurred in Afriolum Lilium, and in A. eversum the whale colony appears to have turned inside out with the atrial apertures on the outside and the branchial apertures in the concavity of the cup. It is. possible that L. glanerti represents a stage in the evolution ofthe colony that is more or less equivalent to the A. Jin condition, Ln ZL. flaverti a thiek bladder eell layer is on both the branchial] and atrial surfaces of the colony, spicules are in the middle layer of test. They are 0,045mm in diameter, and have 9 or 10 rays in optical section. There is a plate-like lateral organ each side of the base of the atrial siphon. A problem in Michaelsen’s interpretation of the colony is how it could be fixed to the substrate, since each surface 1s interrupted cither by incutrent or excurrent apertures af vouids, [t is not impossible that the type specimen is only the upper portion of a colony with the hase (below the cloacal cavily) missing. There was no sign of gonads in Michaelsen’s colony and it cannot be positively assigned to either Atrio/um or THE AUSTRALIAN ASCIDIACEA 4 Leptoclinides. However, the atrial siphons are not as long as in Afriolum and probably it is a Leptoclinides sp. Its most likely affinity is with L. rufus which has similar bladder cell layers and spicules. Determination of species in this genus has been as confused and confusing as in other didemnid genera. Zooids are relatively uniform and do not provide many characters by which species can be distinguished. Too much reliance has been placed on the colour and shape of pigment cells (which are variable, and often lost or altered in preserv- ative). Reliable characters are found in the shape, size and distribution of the spicules, course of the gut, number and arrangement of testis follicles, number of vas deferens coils, form of the branchial siphon, and structure of the cloacal systems. Species occurring in Australia are con- veniently divided into at least 6 groups. However only the dubius and brandi groups can be confidently regarded as monophyletic. These groups are: 1. The dubius species group, characterised by the absence of a distinct spicule-free superficial bladder cell layer, small (not more than 0.04mm diameter) spicules of several types which usually form a layer in the surface of the colony (but sometimes are present throughout) and project in to line the branchial siphons and outline the margins of the distinctly stellate apertures, a small circular lateral organ, usually a wide velum in the base of the branchial siphon which projects up to form a short cylindrical secondary siphon (absent in L. durus) with 6 small lobes around the rim and strong circular muscles, a long gut loop with its distal part bent up ventrally against the proximal part to form a double loop, 9 or more testis follicles in a spherical 3-dimensional mass, the proximal end of the vas deferens coiled only twice or following an S-shaped course, and the ovary producing a single egg at a time, on the outside of the testis over the | proximal end of the vas deferens (at the posterior end of the zooid). Known larvae are large — the larval trunk 1mm long or more, and they have 4 or more pairs of lateral ampullae. Members of this group are L. dubius, L. kingi, L. multilobatus, L. durus, L. echinus and L. levitatus. 2. The coelenteratus group sometimes has a thin superficial layer of bladder cells through which the branchial siphons of the zooids, surrounded by spicules, penetrate to reach the surface. lot tad Spicules and/or pigment cells often are found in the bladder cell layer. In L. apertus and L. cuspidatus spicules are crowded at the surface and there is no apparent bladder cell layer superficially. Spicules are relatively large (up to 0.08mm or more in diameter) the majority with short, conical rays. They do not outline stellate branchial apertures as they do in the dubius group although they usually form a plug inside the siphons when the zooids are contracted. The lateral organs are large and plate-like. The rim of the atrial siphon usually has 5 lobes or papillae on it and 5 rows of spicules mark these openings into the common cloacal cavities. The common cloacal systems are dominated by large, central chambers beneath the terminal cloacal apertures. Also, around their margins, the central cavities are continuous with large horizontal posterior abdominal chambers interrupted by test connectives anchoring the surface zooid-bearing test to the basal test. Testis follicles (3-8) are in one plane, in a circle or ring at the side of the distal end of the straight gut loop, which is either vertical or the whole loop is bent ventrally, at right angles to the thorax. The vas deferens coils at least 4 times. Usually species in this group have a long larval trunk (1.1mm), and the number of ectodermal ampullae is never more than 4 per side. Included in the group are L. apertus, L. coelenteratus, L, cavernosus, L, imperfectus and L. cuspidatus. 3. The rufus group is characterised by its relatively smooth, and often flat surface, with a conspicuous superficial layer of bladder cells, usually mixed with pigment cells. Maximum sized spicules are 0.04-0.08mm diameter with 7-9 conical rays. Four to 6 male follicles are arranged in a circle, converging to the vas deferens which makes from 5-7 coils. Larvae have 24 pairs of lateral ampullae and the trunk is only about 0.6mm long. L. rufus, L. placidus and L. variegatus are flat, the cloacal system dominated by horizontal spaces; while in ZL. longicollis and L. compactus the colony has protuberant lobes on the surface, formed by thickening of the basal layer of test to form a central core. The central core of test is surrounded by cloacal spaces separating it from the outer layer of zooid-containg test. This peripheral sub-surface cloacal space is homologous with the posterior abdominal horizontal spaces, and is crossed by test connectives. 34 MEMOIRS OF THE QUEENSLAND MUSEUM 4. The /issus group may be polyphyletic. Only two species are assigned to it, L. lissus and L. maculatus. Both are flat, without a superficial layer of bladder cells, and with a horizontal cloacal cavity and relatively small stellate spicules. 5. The volvus group has cloacal canals lined on each side with a row of zooids. The surface test is depressed over the canals, which surround zooid-free areas of test that protrude from the surface of the colony. The group may not be monophyletic, as it contains the stalked species L. comitus and L. volvus with some globular spicules, as well as the sheet-like L. rigidus and L. exiguus with stellate spicules to 0.07mm diameter. 6. The brandi group has some of the characters of the coelenteratus group, viz. large cloacal cavities, testis follicles in a single plane and large spicules. However, the regularly stellate spicules, with fewer, longer and more pointed conical rays are in a layer at the surface, and there is no superficial layer of bladder cells. The group may be closer to Atriolum than others, having a longer atrial siphon and a brood pouch. The larva of L. marsupialis resembles that of the coelenteratus group, with only 2 ectodermal ampullae per side and a relatively small trunk — less than 0.6mm long. L. brandi has up to 8 lateral ampullae (like larvae of certain members of the dubius group) in a larva of 0.75mm trunk length. Members of this group are L. brandi sp. nov. and L. marsupialis Monniot, 1989. Leptoclinides fungiformis with a horizontal cloacal cavity beneath the surface zooid-bearing layer of the colony, is distinguished from the rufus group by its unusually small, globular spicules. Leptoclinides is known from only one species in the northern Atlantic (Van Name 1945) and only 2 from the tropical Atlantic (Monniot, 1983). It does not occur at all in the seas around the British Isles, and is not known in the southern temperate Atlantic, the Mediterranean or the eastern Pacific. [t does not occur in Antarctic waters, and is known from only one species in the Subantarctic (Kott, 1969). However, it is well represented in the western Pacific — New Caledonia (Monniot, 1989), Indonesia and the Palau Is (Sluiter, 1909; Monniot & Monniot, 1996), around the Australian continent (where a number of robust tropical species as well as temperate ones occur), New Zealand (Millar, 1982) and Japan (Tokioka, 1953), KEY TO SPECIES OF LEPTOCLINIDES RECORDED FROM AUSTRALIAN WATERS 1. Testis a 3-dimensional mass; post-pyloric part of gut loop bent up to form a secondary loop; usually a false siphon at base of branchial siphon (auhius group)... . . . . 2 Testis not a 3-dimensional mass; post-pyloric part of gut loop not bent up to form a secondary loop; false siphon not present at base ofbranchialsiphon......... 7 Spicules crowded throughout the test; no false siphon gee ee es lege ee L. durus sp. nov. Spicules not crowded throughout the test; false siphon present: 2.06 808. eytept oe fo isy depres} 24S vee 3 3. Spicules generally morethan0.03mm......... 4 Spicules generally not more than 0.02mm diameter. . . ne ne ee ee ee L. multilobatus 4, Spicules globular and stellate; 13 or more rays in optical Ne TrANSVErsesecHiOn:. 0. ht mw. eb. bee ne 3 Spicules only stellate; 9-11 rays in optical transverse SOOUOM fe ial op 'e-enhon tule Foes L, echinus sp, nov. 5. Stellate spicules some with conical, others with fusiform WAV: SY ee, TSE i Aaa: Shaka yt es 6 Stellate spicules with conicalraysonly. .. . . L. kingi 6. Stellate spicules with, 13-15 rays in optical transverse SECON’. p off iar dates Ss 5 L. levitatus sp. nov. Stellate spiculres with up to 17 rays in optical transverse SRCTION ves te ate Whe bot wt L. dubius Ts Colony stalked... a... Sck. ec oS ekeke ns 4 8 Colony notstalked. 2... 2... ee en 9 8. Zooids arranged in double rows around zooid-free areas of test; common cloacal cavities are oesophageal canals 6 Brad Bete ele pe drecdie rete a be web wb Bt 2 L. volvus Zooids not arranged in double rows around zooid-free areas of test; common cloacal cavities are posterior abdominalspaces............ L. fungiformis 9. Spiculesmostly globular. ...... L. comitus sp. nov. Spicules mostly orallstellate.. 2... 2.0.0.2. 10 10. Spicules with more than 15 rays in optical transverse Section tc. emits hae ele L. carduus sp.nov. Spicules with no more than 15 rays in optical transverse HECHOH Ee at i tee ae we Mey Peet eae 1 11. Spicules evenly distributed throughout the colony . . 27 Spicules not evenly distributed throughout the colony .12 12. Superficial bladder cell layer conspicuously thick, always without spiculesinit. .. 2... 2... .0 00 ee 13 Superficial bladder cell layer not conspicuously thick, often with some spicules init, or absent altogether. . 14 13, Spicule rays set in concave base incentralmass... . . aeons sant Pe Poe St coe Y L. umbrosus sp. nov. Spicule rays not set in concave base in central mass . , . soe gt as pw TARA TS phn L. rufus 14. Spicules with chisel-shapedtipspresent ...... . 15 Spicules with chisel-shapedtipsnotpresent .... . 26 15. Common cloacal apertures terminal on conspicuous conical or rounded elevations Common cloacal apertures not terminal, and no conspicuous surfaceelevations ........... 19 16. Stigmatal4—l6perrow ......... L. cuspidatus Stigmatalessthan|]4perrow..........0.. 17 17. Spicules with truncated rays present. . . .L. imperfectus Spicules withtruncatedraysnotpresent ....... 18 i, 30, 41. z2, . Spicules with 7 . Spicule ray -lips sometimes truncated . THE AUSTRALIAN ASCIDIACEA 4 3 9 rays in aptical transverse section, tropleal species ' oF sutras Spicules with 9 1) pays tn muical transverse seution: temperale spectes _ _. L, campeteris sp. nov. Spicules with 13-15 ravs i) optical (ransverse4section, la O.lSmmdiameter. .. . 1. ertnacenssp. nov. Spicules with not more tha 13 rays in optical transverse section, noLmore than 0.1mm diameter 20 Surface test conspicuously depressed over weep sii primary common cloacal canals , . 21 Surface test not conspicuously depressed over Ace circular primary canals - L, variegalis sp. voy, . Common cloacal cavities include posterior abdontinal COMPONEMS oe Common cloacal cavities never posterior abdominal , 25 . Vas deferens coily Stimes around testis... 2... | homaculatuy sp, hoy, Vas deferens toils Sor 6timeswraund testis mews ton = eaharel ane sp. nov, 24 Spicule ray- fips ateer iuaguied pe . Stigmata up te LO per row; tember ate species. - - L. ewiguus sp. now. Stigmata more than 10 per row; tropical specs... . Fy Ce ET ce L. rigidus sp. nov. Spicules to0,096mm diameter . L,aeteulus sp. 10¥, SpiculestoU0amm diameter... L.seninuelus sp. nav, — wt », Stigmata fusiform; brood pouch present: spicule rays long, allenualed; colony not narrow vertical lobes... thoy toe 1, brand) spy. nov. Stigmata not fusiform: brood pouch not present; spicule rays not long, attenuated; colony narrow vertival lobes. 1 longtealliesp, now ee ee ee . Spicules to 0.2mm diameter or more. oe magnistellus sp. nay, Spiculesless than 0: 2mm diameter . 28 . Spicules with chisel-shaped ray tips 29 Spicules withoutchisel-shapedraytips,. 0... 3) . Colony sheet-like; no large surface prominences with tefminal cloacal apertures; spicules with 9 — 13 rays in optical transverse section... 30 Colony not sheet-like; lar surface Prominences ar upright lobes with terminal cloacal apertures: present: spicules with 13 ~ 15 rays in optical transverse section 4 pepe ey pe dh Cavernusny sp. Noy Dark pigment insuperticial bladder cell layer, . . 1 allnimaculatns sp. WO, Dark piemeniael insane icial bladdercelllayer. _L placielus sp. nay. Common ‘cloacal sistem with al uninteraied central chamber . ' - _ L-coclenteratus Common eloacal system Jacks an uninirupted central chamber - 32 Bladder vel) laver present superficially. 0... 33 Bladdervell layer notpresent superficially... L, hivsues . Spicule ray$ 7—Gin Optical transverse section... . he ee / cuvlevtly sp.nov Spiculerays 13 (5 inoptical transverse section ' i -- of senvfirmafes sp.nov, uw Other species of Leproclinides found in adjacent areas are; Leptociinides aperius Mornniot, 1989 trom New Caledonia is Known from a range of colonies of diverse colour and form — yellow orange to, rust to black i investing sheets to upright lobes. Zooids have a wide oper! atrial aperture thal may have been caused by over narcotisation, The vertical gut loop only slightly flexed at the pole resembles that of L, cuspidatus (Sluiter, 1909) as do the Spicules. Both species fave a similarrange in colony form. The New Caledonian species has amore numegrous. vas deferens coils but a smaller larva, Leproctinides marsupialis (Monniot, 1989) also is similar to L. apertes but. differs in its fusiform stigmata and its brood pouch, and is more like L. brenedi. Leploctinides deboensis(Sluiter, 1913) from Aru ls was reported by Sluiter (1913) to havea large alrial lip, and was assigned to Polyyyneraton. However, its holotype (SM4 11) was re-examined by Monniot (1989) and assigned ta Leptoctinides. Re-examination of the type m the present study has conlirmed Monniot’s $ generic assignment, The species resembles £. pleesedes in having a thin superficial laver of bladder cells, and a similar cloacal system, The zonids are relatively small with 8 stigmata in the first 2 rows and 6 in the last row, ashort posteriorly oriented atrial siphon, and 6 coils of the vas deferens around 4—5 male follicles, A few larvae are ih the basal test, Leptoclinices hewwaiiensis Vokioka, 1967 has massive upright or investing colonies with large posterior abdominal cavities. Thickened basal test forms a central mass in the upright colonies, Spicules, found in only one colony, are posterior to the abdominal layer of test, and are more than 0,lmm in diameter, Leploclinides madara Tokioka, 1953 from Japan, resembles L. ryfids in the form and distribution of spicules and bladder cells, although its atrial siphons are larger and pigment cells larger and more ribbon-like, Although Kott (1981) proposed Z. rufus: Eldredge, 1967 asa synonyin of L, madara, Eldredze’s material may include more than one species, including L. rujus (tan With orange streaks) and a Hawaitun species withouta bladder cell layer, Kott (1981) also proposed Z. marmoratus: Millar, 1975 ag a synonym of L.. madara, but appears to be conspecific with L, rufits, having similar colony, zooids and larvae. Lepioclinides marmoratus (Sluiter, 1909) trom Indonesia always has a superticial layer of bladder cells, and a spicule-free area over the anterior end of cach zooid, with 3 clumps of spicules in the centre of each aperture (in the siphon lining), Spicules are also in cloud-like patches in the test around and between the zooids, but elsewhere the internal testis free of spicules and is spongy, The spicules (10 (),03mm diameter) are distinctive with many long, rod-like. blunt-ended or pointed rays. Common cloacal cavities are beneath the large terminal cloacal apertures on surface prominences, and posterior abdominal canals open into these cavities, Atrial apertures are on short posteriorly directed siphons, About 12 SGgmala are inthe middle rows. The vas deferens coils 6 times around a clump of about 7 male follicles crowded into a cirele inca sitwzle plane. ‘The 36 MEMOIRS OF THE QUEENSLAND MUSEUM whole of the gut loop (including the stomach) sometimes is bent up at right angles to the longitudinal axis of the thorax. The species is distinguished from L, rufus and L. cavernosus (both of which have a superficial layer of bladder cells and clumps of spicules in the siphon lining) by its unique small, globular and burr-like spicules with narrow, cylindrical and fusiform rays, and by the discontinuity in the layer of spicules beneath the bladder cell layer. Specimens of L. marmoratus examined are the lectotype (part ZMA TU837.1), ZMA TU837.2, a colony (ZMA TU475,.3) formerly assigned to Didemmum reticulatum Sluiter, 1909, and all specimens of Polysyncraton ocellatum (below). The specimens of P. ocellatum, and most L. marmoratus, are from Siboga Station 64. The exceptions are the specimen from Station 312 (ZMA TU837.2) from 274m and the one from Station 53 (ZMA TU475.3). USNM 5899 from the Philippines, doubtfully assigned to Polysyncraton dubium by Van Name (1918: Station D5109), has similar spicules to L. marmoratus but on re-examination has been found to be Lissaclinum patella. Millar (1975) believed that L. marmoratus was a junior synonym of L. reticulatus: Hastings, 1931 (1mm), with numerous ampullae, although it is larger and has even more numerous ampullae than other species. The principal distinction from L. dubius and other members of the dubius group is the even, hard colony surface, spicules crowded throughout the colony, and the absence of a wide branchial velum and false siphon. The specimen from the Arafura Sea (Tokioka, 1952), with spicules of characteristic form crowded throughout the test, is conspecific with the present species rather than L. dubius. L. dubius: Monniot, 1989 has a larval trunk 1.5mm long, like the present species. However it other- wise resembles L. dubius, especially in having its spicules confined to a surface and basal layer. Leptoclinides uniorbis Monniot & Monniot, 1996, has a hard orange colony with ripple marks on the base, spicules to 0.04mm diameter, 2 coils of the vas deferens around a compact rosette of 6-8 testis follicles and 18 stigmata are in the anterior row. The atrial cavity is said to be limited, but as stigmata presumably open into it, it is not clear how the atrial cavity 1s restricted in L. uniorbis, unless this refers to an extensive prestigmatal unperforated area in the branchial sac, as in the present species. The spicules of L. uniorbis constitute a distinction, having more rays, some with rod-like, flat-tipped rays as well as globular ones. Leptoclinides echinus sp. nov. (Figs 24, 160H; Pl. 3C) TYPE LOCALITY. Western Australia (8.5 n miles NWN Port Hedland 20°13’S 118°28’E, 18m, coll. J. Fromont statn 50 RV Soela 4A/82.13, holotype WAM865.83(1) QM GH2121); Dampier Archipelago, western end of Lewis I., 12m, coll. AIMS Bioactivity Group Q66C 1612 1.9.88, paratype QM G302871). COLONY. Both colonies are large and complex — the complexity possibly being a result of growth. They have a gelatinous appearance (owing to the rather sparse concentration of spicules in the surface) and consist of extensive convoluted sheets, forming irregular, lobed masses. Zooids open on both sides of the lobes and lamellae where basal surfaces are folded together and adhere to one another. A very extensive posterior abdominal cloacal cavity is crossed by strands of test connecting the basal or central test mass to the outer zooid-bearing layer. In life (see photographed specimen QM 60 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 24, Leptoclinides echinus sp. nov, (A, QM GH2121; B-D QM G302871) — A, vertical section through colony showing complex folding; B, thorax; C, abdomen; D, larva, Scales: A, 10.0cm; B—D, 0.1mm. G302871) colonies are dark brown with orange rings around groups of branchial apertures. Spicules are evenly spaced in the surface test. A superficial bladder cell layer is not present. Spicules line the common cloacal cavity although there they are less crowded than in the surface and are only sparse elsewhere. The branchial siphons are lined with spicules, although only occasionally is there a spicule-free area (appearing from the surface as spicule-free spots) around the apertures. Small, (seldom more than (0.03mm in diameter) spicules with 9 to 11 long, pointed rays in optical transverse section, are relatively uniform. ZOOIDS, Zooids.are small. A small false siphon is at the base of the branchial siphon, The branchial aperture has 6 small papilla-like projections around the aperture. The atrial siphon is posteriorly oriented from the postero-dorsal comer of the thorax. Twelve to 14 stigmata are in each row in the branchial sac. The post-pyloric part of the gut loop is bent ventrally and up against the pyloric part to form a secondary loop, Beneath this (at the postenor end of the zooid) isa spherical cluster of about 15 testis follicles. The vas deferens takes an S-shaped course over the outer surface of the testis, The ‘bright orange vesicles’ observed in the living paratype may be maturing eggs. Larvae are large, with a trunk 1.5mm long and the tail wound only halfway around it. There are four bilobed lateral ampullae along each side of the 3 median adhesive organs. These bifid lateral ampullae in duc course subdivide to form 8 finger-like ampullae along each side of the 3 antero-median adhesive organs. THE AUSTRALIAN ASCIDIACEA 4 61 REMARKS. The unique character of this species by which it may be distinguished from others, is the spiky form of the relatively uniform spicules. Otherwise both colony and zooids have the general aspects of the dubius group of species — extensive common cloacal cavities, branchial velum in the base of the siphon, double gut loop, spherical cluster of testis follicles and S-shaped course of the vas deferens. The colonies are more complex than others of the group, but it is assumed that this is a result of growth and maturity. Spicules most resemble those of L. levitatus from Rockingham (see below), which also have long spiky rays and a similar colony — relatively thick with a large cloacal cavity separating the surface zooid-bearing layer of test from the thick basal test, and with the spicules mainly in the surface. However the present species has only one type of stellate spicule, those with long, pointed rays, while LZ. levitatus has a variety of ray shapes, more spicule rays and rays of various lengths in a single spicule. Leptoclinides erinaceus sp. nov. (Figs 25, 158E) TYPE LOCALITY. Western Australia (24 n miles NNW Port Hedland 19°57.2’S 118°25.1’E 22-24m, coll. L. Marsh and M.Bezant on RV Soela 25.9,82, holotype WAM128.93). FURTHER RECORDS. Queensland (Hardy Reef, QM GH5735). COLONY. The holotype colony is a thin (about 3mm thick) encrusting sheet. Spicules are in a layer at the surface, in moderate concentrations in the upper half of the colony and in a simple, sparse layer on the basal surface, but are almost completely absent from the translucent lower half of the colony, where large, crowded bladder cells can be clearly seen in stained mounted sections. Only restricted cloacal canals are evident in the holotype colony, in which adult thoraces are regressed and juvenile vegetative ones developing. Zooids lie horizontally in the upper half of the colony amongst the spicules, and yellowish embryos (but not tailed larvae) are in the aspicular lower half. In the specimen from Hardy Reef zooids line deep circular primary cloacal canals which extend into posterior abdominal spaces. Spicules are large (to 0.15mm diameter) with 13-15 relatively long conical rays with pointed and chisel-shaped tips. The ray length/spicule diameter ratio 1s about 0.3. FIG. 25. Leptoclinides erinaceus sp. nov. (QM GH5735) — A, thorax. B, abdomen. Scales: 0.1mm. A deck photograph of the Hardy Reef specimen shows it as black although the field notes report it as red/purple mottled (McCauley et al., 1993: Q66B2198, III: 5). ZOOIDS. Juvenile vegetative thoraces, and mature abdomina with well developed gonads are present in the holotype colony. The abdomina are about 0.6mm long and it is probable that the total length of an entire zooid would be greater than 1.0mm. The juvenile thoraces have a posteriorly 62 MEMOIRS OF THE QUEENSLAND MUSEUM directed cylindrical siphon with a broad sphincter and 4 rows of stigmata with about 10 per row. The gut loop is relatively long but does not form a secondary loop. The testis is divided into 7 follicles and the vas deferens spirals 6 times around them. REMARKS. The large spicules with numerous sharply pointed rays resemble those of L. brandi, but are smaller with more, longer and more sharply pointed as well as chisel-shaped rays. Further, embryos develop in the basal layers of test while those of L. brandi are in a brood pouch attached to the posterior end of the thorax. L. magnistellus from Tasmania has similar, albeit significantly larger spicules, while L. cavernosus has smaller ones with more rays. L. maculatus has similar spicules to the present species but they are smaller (to 0.07mm diameter) and have fewer (9-11) rays. L. rigidus and L. aciculus also have similar but smaller spicules with fewer rays, but the former has a distinctive superficial bladder cell layer and the latter more vas deferens coils. Leptoclinides exiguus sp. nov. (Figs 26, 159H; PI. 3D) Leptaclinides rufus: Kott, 1975: 9. TYPE LOCALITY. South Australia (Spencer Gulf Point Turton jetty, 5m, coll. AIMS Bioactivity Group 4.2.89, holotype QM G300947). Victoria (Flinders Pier, 5m, coll. N. Coleman 15.6.77 AMPI 203, paratype QM G10166). FURTHER RECORDS. South Australia (Top Gallant L., QM GH1290; Point Turton, SAM E2624; Rapid Bay, E2660; Flinders 1., QM GH1289; Spencer Gulf, QM G301615; Ward I., QM GH1286, GH1318; Kangaroo L, QM G302925). Victoria (ESE side Gabo I., AM Y2287; Western Port, QM G300925, G300994, MV F68745, F68763, QM G308569), COLONY. Colonies are thin (34mm) but rather fleshy, tough and extensive sheets usually with the surface marked into a grey to black marbled pattern or network of narrow depressions (containing double rows of branchial openings) surrounding small solid oval or circular raised areas of solid test about 2mm in diameter. Sometimes spicules are mixed in with a thin superficial layer of bladder cells (QM GH1286),. Inconspicuous common cloacal apertures are evenly distributed, about 8mm apart in the depressed areas, at the junction of canals. Beneath the surface depressions, the common cloacal canals are usually oesophageal, but sometimes are deeper. Zooids are embedded around the periphery of the solid test cores, their atrial apertures directed out to the cloacal canals. FIG. 26. Leptoclinides exiguus sp. nov. (A-C,E, QM G301615; D, QM G300994) — A, semidiagrammatic vertical sections through colony, showing superficial bladder cell layer and deep common cloacal chamber beneath common cloacal aperture; B, zooids lining each side of deep primary common cloacal canals; C, part of surface with branchial apertures along each side of the common cloacal canals that surround the raised zooid-free areas of test forming a mosaic on the surface; D, zooid; E, testis. Scales: A,B, 1.0mm; C, 2.0mm; D,E, 0.1mm. THE AUSTRALIAN ASCIDIACEA 4 63 In 2 specimens from Western Port (QM G300925, G300994) in which zooids are not sexually mature, the cloacal spaces are not developed and the upper surfaces are smooth and even without the depressions that usually develop over the deep primary canals. Spicules are in 3 small clumps or rows converging in the centre of each branchial aperture. Spicules are evenly scattered and moderately crowded in the upper half of the colony beneath the bladder cell layer around the zooids but are sparse, or absent from, the basal one-third to half of the colony, although a sparse layer is present on the lower surface. They are relatively large, occasionally reaching 0.08mm in diameter, although generally the largest are only 0.05mm. They have 9-11 conical rays with chisel-shaped tips in optical transverse section. In preserved specimens dark grey to black pigmented depressions in the surface result from spherical to irregular dark pigment particles around the zooids. Raised areas are white — where a greater depth of spicules is in the zooid-tree solid test. Preservative stains green, reservoirs of green pigment being in the basal test. Living specimens are reported to have had a green matrix with orange zooids or to have been white with black zooids (QM GH1289) or dark purple blue (QM G300994) or orange (QM GH1318). The reference to ‘zooids’ in this context is probably a misinterpretation of the pigment pattern. Specimens from Flinders Pier were black and orange in life (QM G10166, G308569). ZOOIDS. Zooids are relatively small (about 1.5mm long), and not readily removed from the test. Forward projecting columnar epidermal cells are conspicuous on the anterior thoracic wall. Branchial siphons are long, the rim without conspicuous branchial lobes. The atrial siphon is directed posteriorly from the postero-dorsal corner of the thorax. A round lateral organ is in the middle of each side of the thorax, level with the base of the atrial siphon. Ten stigmata are in the anterior row, 9 in the second, 8 in the third and 7 in the posterior row. The gut loop is rounded and open, The oesophagus is relatively short, the stomach almost spherical, the duodenum also relatively short, and the posterior stomach (in the pole of the loop) small and rounded. The distal part of the rectum is a narrow tube. The post-pyloric part of the gut loop is flexed ventrally over the testis, which consists of 5 or 6 follicles crowded into a circle (but not in a single ring), with an outer cap of 6 coils of the vas deferens. Tailed embryos occur in the basal test of a colony collected in March (QM GH1318). Although the otolith and ocellus are well-formed, no other organs were distinguished in the small trunk (0.45mm long). REMARKS, The species is distinguished from other temperate Lepfoclinides spp. with zooids tightly attached to the test (e.g. L. compactus, L. maculatus and L. variegatus) by its double rows of zooids opening into the network of darkly pigmented depressions in the surface test. Like L. variegatus it has larger spicules than L. compactus and L. maculatus. Also, in L. maculatus some spicule rays have truncated tips, black pigment spots usually regularly distributed in the thin superficial layer of bladder cells over the primary common cloacal canals and 8 rather than 5 coils of the vas deferens. L. variegatus has larger spicules with more rays and a smooth colony surface. Usually it can be distinguished from the present species by the position of its cloacal apertures found particularly near the margins of the colony (rather than being scattered over the surface). L. acicu/us has the same colony form as the present species but its spicules are larger with long rays. The tropical L. rigidus has similar spicules but its cloacal systems are more extensive and it lacks the grey meshwork in the surface. L. umbrosus, has dark pigment but lacks the colour pattern of the present species, and has larger spicules with more and shorter rays. Leptoclinides fungiformis Kott, 1972 (Fig. 27) Leptoclinides fungiformis Kott, 1972b: 180; 1998: 86. NEW RECORDS, ? South Australia (Investigator Strait, MV F68815, F68820). PREVIOUSLY RECORDED. South Australia (Pearson I. —SAM E911 syntypes Kott, 1972b). COLONY. Colonies are stalked heads, up to 7¢m high, of which the head is about 2cm and the thick, transversely wrinkled stalk is Scm. Basally, the stalk expands slightly into a holdfast. The head is slightly laterally flattened, wider at the top and narrowing to the stalk. One or 2 large common cloacal apertures are approximately in the centre of the upper free surface of the head. The outer surface of the colony is firm and smooth, but although it is firm the test is not tough. The position of the branchial apertures on the surface of these colonies is marked by a small dimple. The crowded spicules obscure the arrangement of the zooids. A superficial layer of bladder cells was not detected, and spicules are crowded in the surface. Spicules are less crowded 64 MEMOIRS OF THE QUEENSLAND MUSEUM FIG, 27. Leptoclinides fungiformis (SAM E911) — A, colony; B, zooid; C, gut loop and oesophageal bud. ? L. fungiformis (MV F68820) — D, thorax; E, abdomen. Scales: A, 1.0cm; B—E, 0.1mm. but evenly spaced around the zooids and in the central test of both the stalk and the head. They are small (to 0.02mm in diameter), with numerous (about 15) short, conical, but sometimes flat-ended rays in optical transverse section. A few have only about 7 conical rays in optical transverse section. Shallow, but extensive, posterior abdominal common cloacal cavities separate the central test from the surface layer around the head of the colony, and secondary canals from cavities at oesophageal level open into them. Longitudinal spaces in the stalk may be vascular, or at least partially the result of shrinkage of the test. ZOOIDS. In the syntype material zooids are in the vegetative phase, with thoracic and abdominal buds. The thorax and abdomen are of about equal length. The branchial apertures on short cylindrical siphons are smooth-rimmed. The posteriorly directed atrial aperture is on a conspicuous siphon projecting from the postero-dorsal corner of the thorax. Its distal part is bulbous, with a wide, thick sphincter around it. A velum in the base of the atrial siphon projects into the siphon as a conical false siphon. Some fine longitudinal muscle bands are on the thorax. Thoracic buds from the oesophageal neck have 4 rows of about 8 stigmata but they could not be THE AUSTRALIAN ASCIDIACEA 4 65 counted accurately. The gut forms a fairly open loop, flexed ventrally in front of the stomach. Kott (1972b) reported a single male follicle, confirmed by Monniot (1989). Re-examination of the syntype material has not confirmed this, and the structure of the testis is uncertain. A single egg is present in the test behind each zooid. Larvae are not known for this species. REMARKS. The colony resembles that of the sympatric L. volvus (also occurring in South Australia). However, L. volvus lacks a posterior abdominal cloacal cavity and has double rows of zooids surrounding protuberant zooid-free areas of test, a superficial bladder cell layer, a short, laterally directed atrial siphon, a distinct branchial siphon, short conical spicule rays, and spicules present throughout the colony including the stalk. The specimens from Investigator Strait doubtfully assigned to this species are stalked, with spicules in clouds at zooid level and in the central test. The branchial siphon has pointed lobes, the atrial siphon is short at mid thorax level, 6 testis follicles are arranged ina circle and 4 coils of the vas deferens surround them. More material is needed to establish whether the differences (principally in the thorax) from the syntypes are significant, or are merely associated with the vegetative condition of the syntypes. Polysyncraton pedunculatum is a sympatric species with a similar stalked colony. It is distinguished by its soft, aspicular test, atrial tongue and loose coils of the vas deferens. Leptoclinides imperfectus (Kott, 1962) (Figs 28, 159A; PI. 3E) Askonides imperfectus Kott, 1962: 294 (part, holotype, from Reevesby I.). Leptoclinides imperfectus: Kott, 1998: 86. Leptoclinides rufus: Kott, 1972a: 16 (part, specimen from Port Noarlunga); 1975; 9 (part, specimens from 25m), NEW RECORDS. Western Australia (Albany, QM G302883). Great Australian Bight, off Ceduna, SAM E2507; 32°24°S 133°30°E, QM G9281). Tasmania (Waterford Bay SAM E2842). PREVIOUSLY RECORDED. South Australia (Elliston Reef—QM G9283, SAM E2509 Kott, 1975; Reevesby I. — AM Y1348 holotype Kott, 1962; Port Noarlunga - SAM E2604 Kott, 1972a). COLONY. Colonies are thick, irregular masses or investing sheets, around weed stalks or on flat substrates, 0.5-lem thick, with dome-like to conical protuberances up to lem in diameter, each with a central, apical, cloacal aperture. These protuberances sometimes are separated from one another only by a narrow crease, but in other less regular colonies the occurrence of these swellings is more random. Between the branchial apertures, the surface of the colony sometimes has pointed spicule-filled papillae which occasionally also are present inside the cloacal apertures in the roof of the cloacal cavities. The cloacal apertures open from large chambers in the centre of each surface swelling, and atrial apertures open directly into the roof of the cavities as well as into the oesophageal canals that extend between clumps of zooids around the periphery of the central chambers. Most of the zooids are in the roof of the primary cloacal cavities and have their whole abdomen bent up against the thorax. An opaque, layer of crowded spicules is at the surface. A conspicuous spicule-free superficial layer of bladder cells is not present. The spicules become less crowded toward the lower half of the colony. In one colony (QM 302883) they form a layer in the floor of the cloacal cavity and are less crowded but usually present at abdominal level and on the base. Three vertical spicule-filled ridges in the branchial siphon lining are seen from the surface as arcs or small clumps of spicules sometimes outlining one or more lobes of the stellate aperture. A clear spicule-free area of test over the anterior end of each zooid surrounds each branchial aperture or sometimes small spicules are present around each aperture, gradually merging with the surface spicules between the apertures. Spicules are of moderate size, generally not more than 0.04mm in diameter, but occasionally larger spicules, up to 0.1mm are found. Eleven to 13 conical rays are in optical transverse section but are of two types, one with chisel-shaped tips and the other with short truncated, flattened tips A colony from Elliston Reef (QM G9283) is reported to have been ‘mostly grey with orange around the siphons’ (probably the cloacal apertures) and ‘reddish-brown’ in life. The colony from Port Noarlunga (SAM E2604) was orange to light fawn in life and the one from Albany (QM G302883) had a grey, orange and red marbled pattern, A cloacal cavity was not detected in the hard, thin, and smooth colonies (QM G9281, QM G302883) with juvenile thoraces that do not open to the surface. ZOOIDS. Zooids are just under 2mm long overall, although usually less owing to contraction of the thorax. Thoraces are wide, with about 10 66 MEMOIRS OF THE QUEENSLAND MUSEUM fusiform stigmata per row, and posteriorly oriented atrial siphons extending from their postero-dorsal corners. The branchial siphons are long and cylindrical and the aperture is not lobed. A flat, circular lateral organ to 0.09mm diameter is on each side of the thorax opposite the last row of stigmata. Fine thoracic longitudinal muscles are conspicuous on the anterior body wall. Zooids have a particularly long oesophageal neck (half the total length of the thorax). The gut loop FIG. 28. Leptoclinides imperfectus (A-C,E, QM G9283; D, SAM E2842; F, AM Y1348)—A, colony from upper surface; B, semidiagrammatic vertical section through a colony showing spicule distribution (the central cavity accommodates the weed stalk around which it has grown); C, branchial apertures; D, thorax; E, zooid, the thorax probably a juvenile vegetative one; F, larva. Scales: A, 1.0cm; B, 1.0mm; C, 2.0mm; D, 0.5mm; E-F, 0.1mm. is long and rather narrow, with an almost elliptical stomach, a long duodenum with a slightly bulbous distal end, and a small almost spherical posterior stomach. The proximal end of the rectum has a distinct elbow. Sometimes a fecund copepod is in the lumen of the gut. The testis, opposite the relatively short post-pyloric part of the gut loop, consists of 6 to 8 long club-shaped follicles, arranged in a circle. The vas deferens coils 7 times. THE AUSTRALIAN ASCIDIACEA 4 67 Eggs are present in some specimens either anterior or posterior to the zooids (possibly moving back following fertilisation). The specimen from the Great Australian Bight with juvenile thoraces (QM G9281) has maturing testes but no eggs. It may be protandrous, the eggs developing after the thoraces have completed their regeneration and the cloacal cavity has reappeared. Tailed larvae are found in the type specimen collected in December. The larval trunk is about 0.6mm long. The tail is wound almost the whole way around it, and there are 4 lateral ampullae on each side of the 3 median adhesive organs. REMARKS. The stellate spicules with chisel- shaped rays resemble those in L. maculatus and some with truncated rays are also present in the latter species. The species are distinguished by the colony form, pigment distribution and absence of a spicule free superficial layer of bladder cells in the present species. The colony resembles L. dubius with dome- like swellings and spicules in the surface layer of test. However, it has none of the characteristics of the dubius group. Tropical L. cavernosus, which Kott (1962) originally thought was conspecific with the present species, has spicules of similar form and distribution, and similar numbers of testis follicles. However, it has larger zooids, a superficial layer (albeit thin) of bladder cells, a different larva and spicules with more numerous and more sharply pointed rays. In the temperate L. compactus a conspicuous superficial bladder cell layer lacks spicules, while in the present species the superficial layer of test is packed with spicules and there is no obvious bladder cell layer. L. coelenteratus, another species with large uninterrupted cloacal cavities, has larger zooids and spicules with more and shorter (and sometimes quite blunt) rays. Leptoclinides kingi Michaelsen, 1930 (Figs 29, 161D; Pl. 3F) Polysyncraton dubium: Hartmeyer, 1919: 136. Leptoclinides dubius: Michaelsen, 1930: 507 (£2 king). Kott, 1962: 289 (f, king?) NEW RECORDS. Western Australia (Buccaneer Archipelago QM G302870). Queensland (Wistari Reef, QM GH234; Whitsunday I., QM GH5369; Haslewood I., QM GH 5373). PREVIOUSLY RECORDED. Western Australia (Cape Jaubert— Hartmeyer 1919; Shark Bay — Michaelsen 1930). Queensland (Hervey Bay — QM G9284 Kott, 1962; Campwin Reef, Sarina— QM G4962 Koitt, 1962). COLONY. Colonies are large, fleshy sheets, with the surface raised into rounded ridges and other (sometimes irregular) prominences. Common cloacal apertures are apical or evenly spaced along surface ridges. Sometimes narrow branches of the colony subdivide and anastomose to form a fleshy 3-dimensional reticulum. Spicules are crowded in the surface test, and also in the minute papillae that sometimes project from the surface between the branchial apertures. Spicules also are in a layer in the base of the colony. Elsewhere in these fleshy colonies the spicules are either absent or scattered sparsely. Spicules in the superficial layer are sometimes separated into clumps rather than being evenly spaced. Some of the ridges and irregularities on the surface appear to result from thickened test rather than the size of the cloacal cavities, although the large cavities beneath the cloacal apertures cause many of the surface elevations. Sometimes a branch of the colony has a large central common cloacal chamber, interrupted only by occasional test connectives from the surface zooid bearing layer to the basal test. Common cloacal canals penetrate the test posterior to the zooids. Atrial apertures sometimes open directly into posterior abdominal cavities and sometimes into narrower secondary canals at oesophageal level. Spicules are small (to 0.04mm diameter), generally with 13-15 broadly based conical pointed rays, although some are spherical with flat-ended rays. Spicules line the branchial siphons and from above the star-shaped apertures are outlined by a line of white spicules. Living colonies are reported to have been light yellow, green (QM G302870). ZOOIDS. Zooids are small and contracted in the examined colonies. The branchial aperture has shallow lobes and is on a short siphon with a branchial velum in the base forming a false siphon. The atrial aperture is on a relatively short, posteriorly oriented siphon, with a smooth rim. The branchial sac has 10-12 round-tipped stigmata per row. The distal part of the gut loop is flexed ventrally up against the pyloric part to form a secondary loop. A spherical mass of 9-16 male follicles has the sperm duct making an S-bend on its outer surface. One small egg is present on the outside of the testis in the examined specimens. Larvae, present in colonies from Sarina (QM G4962) in August (Kott, 1962) and from Wistari Reef (QM GH234) in November, are large, witha 68 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 29, Leptoclinides kingi (A,C, QM G302870; B,D, QM GH234; E-H, QM G4962) — A,B, colonies; C, semidiagrammatic vertical section through colony showing horizontal posterior abdominal cloacal cavity and some branchial apertures opening from a central internal space resulting from folding of the colony; D, branchial aperture from above showing spicules in lining of branchial siphon; E, thorax, showing false siphon in base of branchial siphon; F, abdomen showing double gut loop and large egg; G, grape-like cluster of male follicles and vas deferens; H, larva. Scales; A,B, 1.0cm; C, 1.0mm; D-H, 0.2mm. trunk 1.2mm long, and 6-8 pairs of lateral ampullae. REMARKS. The fleshy colonies resemble those of most species of the dubius group in having a single layer of spicules in the superficial test and spicules outlining the margins of the stellate branchial apertures. The zooids also are similar, having a branchial velum forming a false siphon, a double gut loop, and a large spherical testis with many follicles and an S-shaped course of the vas deferens on the surface of the testis. Zooids of the present species may be smaller than L. dubius, but this could be only apparent, resulting from contraction. Kott (1962) THE AUSTRALIAN ASCIDIACEA 4 69 distinguished L. dubius f. kingi from L. dubius f. typicus by its better developed cloacal chambers. However this probably is associated with colony size, and a more reliable character distinguishing the species from others in the dubius group is the form of the spicules. In the present species spicules are mostly those with conical rays; and the longer slate-pencil-like and fusiform rays common in L. /evitatus, L. dubius and L. multilobatus are not found. Spicules resemble those of ZL. durus, although in the latter species they are crowded throughout the test rather than being in a single layer at the surface. The larvae are the same size as the smaller ones of L. dubius, with similar lateral ampullae. Leptoclinides levitatus sp. nov. (Figs 30, 160-1; Pl. 3G) TYPE LOCALITY. Queensland (Little Black Reef, 19°46.25’ 149°22.0’E NW face, 15m, coll. AIMS Bioactivity Group 21.10.87 Q66C0909, holotype QM GH5380). Western Australia (Warnbro Sound near Rockingham, coll. AIMS Bioactivity Group 20,3.89 Q66C2776, paratype QM GH5456). FURTHER RECORDS. Queensland (Penrith I., QM 308700). COLONY. Both type colonies are large, with a thick (to 2cm) layer of basal test separated from the upper zooid layer by extensive cloacal cavities and the surface raised into long rounded ridges. Large circular common cloacal apertures are spaced at random along the highest part of the ridges. They are not conspicuous in the preserved material but they are in life. The colony from Penrith I. is a large irregular mass, with protruding conical lobes with a central mass of test continuous with the basal test. The outer surface is smooth but there is no superficial bladder cell layer. Small spicules are found in crowded clumps or in an even layer in the surface test and lining the common cloacal cavity. They are scattered more sparsely through the remainder of the test. They fill the lining of the branchial siphon, but there is no interruption in their distribution between the branchial lining and the surface layer of test. Thus, although star-shaped apertures are evident they do not appear to be outlined by a single marginal row of spicules. Spicules are up to 0.04mm in diameter with 13 to 15 rays in optical transverse section. The majority have long, pointed rays of different lengths (in the one spicule) but some have fusiform, or blunt and rod-like or slate-pencil- like rays. Some of the smaller spicules are almost FIG. 30. Leptoclinides levitatus sp. nov. (A,D, QM GH5456; B,C, QM GH5380) — A,B, colonies; C, thorax showing false branchial siphon; D, abdomen showing double gut loop. Scales: A,B, 2.0cm; C,D, 0.2mm. 70 MEMOIRS OF THE QUEENSLAND MUSEUM globular with flat-tipped rays and occasionally the rays have chisel-shaped or divided tips. All specimens were photographed in situ. The holotype was bright orange-red, the paratype pink with patches of green that may have been symbionts (possibly Prochloron) on the surface, and the other colony was black. All are white in preservative. ZOOIDS. The branchial siphon is long, with a short velum forming a short false siphon in its base. The branchial sac has 10 to 14 stigmata per row, the anterior row having 13 on the right and 14 on the left. The gut loop is long, its posterior pyloric part being bent up to form a secondary loop. The numerous (up to 15) male follicles are clumped together to form a spherical three- dimensional mass and the vas deferens forms an S on the outer surface of the spherical mass of male follicles. REMARKS. The discontinuous records suggest a relatively wide range for L. lJevitatus. The species is a member of the dubius group, separated from other members of the group by the long rays of the spicules. The spicules have the fusiform and slate-pencil-urchin type rays found in L. dubius, although the shorter-rayed spicules of the latter species do not occur and the spicule rays are less numerous (13 to 15 in optical section). The spicule rays of L. echinus are equally long but always pointed and not as variable in length as in L. /evitatus. The spicules resemble those of L. durus but they are not crowded throughout as they are in the latter species and they have longer rays. Leptoclinides lissus Hastings, 1931 (Fig. 160F) Leptoclinides lissus Hastings, 1931: 93. Millar, 1963: 704. Kott, 1998: 86. Not Leptoclinides lissus: Brand et al., 1989: 425 () WP lepes ote seme! P. meandratum 8. Common cloacal cavitiescircularcanals. . . . Common cloacal cavities horizontal spaces... . . .. P. robustum sp. nov. ~ — o i ae . Zooids dark green in long-term preserv ative THE AUSTRALIAN ASCIDIACEA 4 Spicules all burr-like with fine uniform rod or needle-like rays P pulchrun sp, now, Spicules not all ‘als like with fine uniform rod or needle-likerays 22 4 ; nv Spicules stellate. rays mostly conical... oS ll Spicules not only stellate, rays flatand/or round-tipped ws wellusconical, .. 622.0 e sa ert w» eis Spicules to 008mm or more diameter. ray lengthy sivul diameterratioabout@.25. 2.0... 0.2.0. .005 Spicules not miore than 006mm diameter, ray oe spiculediamvterratioW4. 2... P eehtiatum sp. nov. , Colonies upnght, entire or subdivided into 2 or 3 lobes, each with a single terminal common cloacal opening. . cy eee. sagen tint Mss gin eauas eg tt de OW Pjugosum Colonies sheei-like, not upright lobes with terminal common cloacal apertures, . . . . P scobinumsp.noy. a) pices with 20 or more rays in Dotteal transverse section Spicules with, fewer thi 0 tay in optical transverse section. 2. . bes ‘eT ae a1 5 ald . Spicules sometimes hallow: vesicles in colony surface . Po cirenhin Spieulesr never ethollow; no vesicler] in Loulannt surface . . . Pemitiforme sp. nov. - Spicules inelude some with reg conical rays; spicules crowded at thoray level . P dentatum sp. nov. Spicules never with regular conical rays: spicules ina single layer atthe surface P flammeum sp. nv. . Spicules to W.07mm diameterormore — - - ; 7 Spicules less than 0.07mmdiameler . 2... 8. 28 . Spicules all stellate; spicule rays ull vonical, pointed, or truncated orchisel-shaped. . 2... oe Ik Spicules not all aS sae rays Hat or Stunest pret orrounded . i RAYS TE . Cloacal systems an isolated stip of zovids arbi, Ry ventral commoncloacal aperture =P lawenm sp.nov Cloucal system not an isolated group of zovids sround a central commonecloacalaperture 2... 4. , IY . Ray lengthspicule diameter ratio never more than 0.2. eh -staed ses tcgee, i 40-siar, sh i tee FP. infiindthilunrsp. nov. Ray lengtt/spicule Oenetet ratio usually more than 0.2 ate Uct tated othe rv 20 ee . . Spicules with up to 9 rays in optical transverse seelion; vesicles sureotind branche ‘per mane insurface test, . Pi stderivsp. nov, Spicules with up to 7 1 or more ravs in optical transverse section; vesicles do not surround branchial apertures in BU Pagatest: alo et, Pde 6 ihe ceo 2! . SpiculediameterioO.lmmormore, ., 2... ,. 23 Spicules diameter less than 0, bain fei . Branchial apertures along each side of deep pritiany eloacaleanals |, , , P pseuderugosum Branchial apertures not along each aide of deep primury cloacal canals... , Pee P arafurensis wou oy « PB fhasmanense sp, nov. Zooide notdark preen! in long-term preservative ,, , 24 - Spiculediameterto more thanQ.Jmm... 2... . 28 Spicule diameter to 0, lan P regulum sp. nov. 25. Spicules s sometimes have chisel-shaped tips... . . ‘ P legeim sp. nav. 91 Spicules never have chisel-shaped tips. , FB agi sp. nov, . Spicules include some conspicuously stellate ones with few conical rays fericutis sp. nov, Spicules do not include iad aa stellate ones with fewconicalrays 2... . Mag . Spicule ray long. often flattened aa tongue-shaped mike P. pantoniue Spiculer rays short never flattened and rongue-shaped, P. scorteum sp. nov. . Spicules include stellate ones with conicalrays. .. , 30 Spicules do not include stellate ones with conicalrays . 29 . Pigment cells oer in surfaee test; tropient species Ser idleiedes fe Po rugesam Pigment cells not present in surtace test; temperate Species _ Pdiscoides Sp. noe. 30), Retractormusclepresem ; 1. tee. Sl Retractor muscle nbt present. ee 35 31. Spiculesto0.05mm diameterormore, ©. 2. 0. . 32 Spicules not morethan 004mm diameter... . .. . 34 . Spicule rays to 1S or more in optical transverse section Ee alee oo. Ets (4 P_ateaniimsp. nov. Spicuile rays less than 15 in optical wansverse section, 34 Black squamous epithelium present; no dense rippled colony base. 2... 0 2 8 ' . Poorbiculum Black squamous epithelium not recent with dense, rippledcolony base, 2... ee P millepore Spicules globolarand stellate. 2 P magnetec Spicules only stellate... , . P papyrussp. nov, 35, Spicules with 17 w 19 tan pointed rays in optical transverse section. 2.2... P. pallialum sp.nov, Spicules with 7 —Y rays in optical transverse section oF aria! +} -. Prubitapum sp, nov, Species reported from adjacent water but not yet recorded from Australia are: Polvsyneraton aspicularum (Tokioka, 1953) from Japan has 5-12 male follicles, and up to 4 lateral ampullae on each side of the Jong larval trunk. It lacks spicules, but unlike the stalked P pedyneulatum (which also is aspicular) it is a sessile colony. Specimens wrongly assigned to this species by Kott (1962) are P. puraw trom Mackay and a related but distinct species (7 nobusrisi) from Rottnest I, The Japanese species resembles magnilarvum Millar, 1962 from South Africa only in the size of the laryal trunk (see P robustunr). Polysyncraron St ia Kot, 1975 (<2 pecimenlanm) is discussed below, Palysyneraton chondrilla (Michaelsen, 1924) from the subantarctic islands of New Zealand (Millar, 1982) forms soft, fleshy, uptight colonies to 8cm high, narrow basally and undivided, with terminal common aperture. The small (to 0.035mm diameter) spicules are principally in a layer in the surface test but occasionally in other parts as well. One colony is known to be aspicular (Colville Channel: Michaelsen, 1924). Zooids have 4 or 5 male follicles and 4 coils of the vas deferens. The species resembles ? ream which also is aspicular but has about 8 male follicles. Polvsvncraion jugosim (Herdman & Riddell, 1913), which Koll (1962) thought to be synonymous with /? 33, 34 ee chondrilla, has similar spicules, stellate with 7-9 rays in optical transverse section. It is distinguished by its 8 male follicles. Polysyncraton fuscum Nott, 1892 from Auckland, was proposed (Michaelsen, 1924), and generally accepted (Brewin, 1957; Millar, 1982), as a junior synonym of P paradoxum Nott, 1892 (also from Auckland). However, although the gonads are similar, the spicule distribution is different and P fuscwm had a retractor muscle which has not been reported in R paradoxum. In P. paradoxum spicules are throughout the colony but in P. fuscum they are present only around the zooids. Nott (1892) refers to a transparent colourless outer hyaline layer of test and large zooids which, with the location of the spicules, resemble the tropical P purou, P. otuetue and P- meandratum. Of these 3 tropical species, only P. meandratum has relatively small burr-like spicules that could be like those of P fiscum. Material from the type locality, Auckland Harbour, is needed to establish the form of the spicules and the exact relationships of this species. Tropical species are known to occur in Auckland Harbour. Polysyncraton lithostrotum (Brewin, 1956) was recorded only from sub-antarctic locations (Brewin, 1956, 1958; Millar, 1982) but now is known from the Coromandel Peninsula (QM G300968, G300989). The newly recorded specimens, like Brewin’s (1956) type material, are orange. The species is characterised by its surface marked off into polygonal areas, each a separate system, with a central cloacal aperture, the testis divided into 2 follicles, a narrow atrial tongue of various lengths, a small retractor muscle (sometimes not detected), and spicules to about 0.06mm diameter with 9-11 short, blunt, almost globular rays. The large larvae from QM G300989, with the trunk about 0.7mm long, have about 35 short, round-tipped ectodermal ampullae around the anterior end of the trunk giving it a scalloped appearance. The 3 antero-median adhesive organs are small with short cylindrical stalks. Ocellus and otolith are present. Neither adult organs nor blastozooids have been detected. Brewin’s (1956) record ofa larva 1.5mm long appears to include the tail. P glaucum and P. multiforme as well as P pavimentunt Monniot, 1993 (>P_ Jithostrotum: Monniot, 1993, see below) are tropical species with similar isolated systems but different spicules. Polysyncraton mortenseni (Michaelsen, 1924) from New Zealand, has large (about 0.085mm diameter) spicules with round-tipped rays, 2 or 3 testis follicles and 6 coils of the vas deferens, Specimens from Tasmania were wrongly assigned to P mortenseni by Kott (1954, 1962). P tasmanense, Leptoclinides magnistellus and Trididemnum cristatum are erected to accommodate them. Polysyncraton multipapillae Monniot, 1993 from New Caledonia forms red-currant coloured colonies which become greenish in formalin. Globular spicules (to 0.03mm diameter with thick flat-tipped rays) are crowded throughout, and the colonies are brittle. Unicellular algae are in the common cloacal cavity and embedded in the surface test, but it is not known if these are pro- or eukaryotic; and the contribution made by these cells to the colour of the colonies has not been determined. The small MEMOIRS OF THE QUEENSLAND MUSEUM zooids lack an atrial tongue. They have a retractor muscle, about 8 stigmata per row, about 5 testis follicles and 7 coils of the vas deferens. The larval trunk is about 2.0mm long, with 15-25 adhesive organs and about 15 ectodermal ampullae along each side of the adhesive organs. Restricted cloacal canals are at thorax level. Spicules resemble those of P meandratum but have fewer rays, and are more evenly distributed. Larvae are unique, the number of adhesive organs being exceeded only by Diplosoma multipapillatum Kott, 1980 from Fiji. This is the only known species of Polysyncraton with possibly obligate green cell symbionts. Although the symbionts are transported on the larvae, Monniot’s (1993) report of a rastrum is incorrect. Polysyncraton nigropunctatum Sluiter, 1909 (ZMA TU838) from Indonesia, is the only species correctly assigned of the 5 he described in this genus — the others being Leptoclinides spp. The type colony is an irregular sheet to 2mm thick with zooids arranged in a row along each side of the circular canals beneath the slight surface depressions around zooid-free areas 2 to 3mm in maximum extent. Spicules to 0.04mm diameter, with short, strong conical rays, are in a layer beneath the surface bladder cell layer and on the base of the colony, but are absent between. Zooids are small, with 4 rows of 5 or 6 stigmata. Five male follicles have 5 coils of the vas deferens around them, Clearly defined black pigment spots are in the upper surface. The laryal trunk is 0.6mm long and has an ocellus and an otolith, 4 rows of stigmata in the pharynx, 4 lateral ampullae on each side of the 3 antero- median adhesive organs, and an external lateral ampulla on the left side from the waist of the larval trunk. Blastozooids are not present. Polysyncraton paradoxum Nott, 1892 from Auckland, New Zealand (see Millar, 1982) is an encrusting sheet. Although Nott (1892: 318) reported that the spicules were ‘of fairly large size’ Brewin (1957) refers to small (to 0.018mm diameter), burr-like spicules with many short blunt rays present throughout the colony. Seven—10 testis follicles have 4 coils of the vas deferens around them. Zooids have a long atrial tongue, but a retractor muscle is not reported. The species resembles P rugosum Monniot, 1993 from New Caledonia and is distinguished from it only by having 4 rather than 3 coils of the vas deferens. P. papyrus also is similar but it does have a retractor muscle. Palysyncraton paradoxum: Kott, 1954 is a specimen of P papyrus, and P. paradoxum: Kott, 1972b is Leptoclinides compactus. Polysyncraton paradoxum var. mahenum Michaelsen, 1920 from the Seychelles (

Didemnum mortenseni: Kott, 1954) from the NE coast of Tasmania (AM Y1541) have similar spicules to the present species, but the largest is only 0.114mm in diameter and they have only 9-11 long, pointed rays. This species lacks vesicular cells and has irregular and complex colonies with outgrowths fusing with other parts of the surface. P. mortenseni: Kott, 1962 from Oyster Bay, Tasmania, has even larger spicules and is the holotype of Leptoclinides magnistellus. Polysyncraton tasmanense sp. nov. (Figs 68A, 164-1) Didemnum mortensensi: Kott, 1954: 163 (part, from BANZARE Station 115). TYPE LOCALITY. Tasmania (NE coast, BANZARE statn 115 676-128m, March 1931, syntypes AM Y1541). COLONY. Colonies are thin and irregular, with solid but narrow cylindrical protrusions from some parts of the surface which occasionally overgrow it to form a complex 3-dimensional 137 colony. Common cloacal canals are shallow and thoracic. Spicules are crowded throughout, large, stellate, to 0.114mm in diameter and with 9-11 conical rays in optical transverse section. The ray length/spicule diameter ratio is about 0.33. Tips of the rays are usually pointed but some are chisel-shaped and occasionally forked. Colonies are pale green after long-term (nearly 70 years) perservation and the dark blackish-green zooids can be seen through the branchial apertures on the surface. ZOOIDS. The size, contraction and dark colour of the zooids obscured their structure. Four rows of stigmata and a wide atrial opening without an atrial tongue were detected. Kott (1954) saw 5 male follicles and 2 coils of the vas deferens, although this was not confirmed on re- examination. Larvae are not known. Those shown in Kott (1954) are from the holotype of Trididemnum cristatum. REMARKS. The species is erected on the basis ofits unique coloured zooids, the size and form of its spicules, and its complex colony form. Although the spicules of P. tegetum are similar with a similar range in diameter and occasional chisel-shaped rays, they have more rays, and the zooids have more coils of the vas deferens. P sideris has similar though smaller spicules but with fewer rays and is further distinguished by the vesicular cells in the surface test. Polysyncraton tegetum sp. nov. (Figs 68B,C, 164G) Leptoclinides reticulatus: Kott, 1975: 8 (part). Didemnum moseleyi: Kott, 1975: 9, TYPE LOCALITY. South Australia (Great Australian Bight 32°24°S 133°30°E, coll. P. Symonds, Prawn Expedition 23.8.73, holotype SAM E2698; paratype, SAM E2664). COLONY. In preservative colonies are thin, hard and investing sheets (SAM E2698) to cushions (about lem thick) with zooids crowded in the upper half (SAM E2664). Colonies are smooth and featureless without conspicuous branchial apertures, and are opaque and cream coloured with brownish transparent zooids. Spicules are less crowded in the superficial and the basal layers of test, than they are in the remainder of the colony. They are all stellate, but there is a great range in sizes (to 0.125mm, but usually less); and there are several different shapes. Many of the smaller spicules have 7—9 long, pointed (some- times almost fusiform) rays in optical transverse section with a ray length/spicule diameter ratio 0.375-0.4, but the larger spicules have 11-13 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 68. A, Polysyneraton lasmanense sp. nov. (AM Y1541)—A, portion of colony, B.C, Palysyneraton tegen sp. noy. (B, SAM E2664: C, SAM E2698) — B, thorax; C, abdomen. D-E, Polysyneraton tenuicutis sp. nov. (WAM 390.75) — D, thorax; E, abdomen. Scales: A, 0.S5em; B-E, 0.1mm. well-spaced, but relatively short conical rays with a ray length/spicule diameter ratio of about 0.2. A few of the smaller spicules have shorter, even, conical tips widely separated from one another on the central spherical mass. Some of the spicule rays have chisel shaped tips. Cloacal cavities were not detected, but probably are narrow canals at thorax level. ZOOIDS. Zooids are about Imm long. In the holotype abdomina are well-developed and 7 coils of the vas deferens surround up to 8 long club-shaped follicles. Vegetative buds are in the oesophageal region, but thoraces are disintegrating. The paratype which was taken at the same time, does not have mature testes, but the thoraces are large and well-preserved, with a relatively long branchial siphon, a distinct anterior atrial lip, a large lateral organ opposite the second row of stigmata (near the rim of the large sessile atrial aperture), and a long tapering retractor muscle from the anterior part of the oesophageal neck. Larvae are not known, THE AUSTRALIAN ASCIDIACEA 4 REMARKS. Characteristics of this species are its limited cloacal spaces, large lateral organs, relatively numerous vas deferens coils and testis follicles, and large crowded stellate spicules. Both holotype and paratype are from the Great Australian Bight. The holotype was assigned to Leptoclinides reticulatus (with a specimen of Leptoclinides variegatus) by Kott (1975). Kott (1975) had assigned the paratype to Didemnum moseleyi. Despite its lack of gonads, it has large thoraces, anterior lateral organs, atrial tongue and retractor muscle which together are characteristic of Polysyncraton, and its spicules are identical with those of the holotype. P. infundibulum from South Australia has uniform, short-rayed stellate spicules with short conical rays, and they are smaller than those of the present species, never exceeding 0.075mm in diameter. The three specimens of Didemnum mortensi: Kott, 1954 from the NE coast of Tasmania with large stellate spicules, belong to 2 different species. One (AM Y2321) is the holotype of Trididemnum cristatum and another (AM Y 1542) may be the same species. The five male follicles and 3 to 4 coils of the vas deferens which Kott (1954) reported for D. mortenseni were not found in any of the re-examined material. They are unlikely to have been in the specimens assigned to T. cristatum but probably were in the small dark green zooids of the third specimen (AM Y1541) — the type specimen of Polysyncraton tasmanense. The latter species has fewer spicule rays than P. tegetum (see also P. sideris), Polysyncraton tenuicutis sp. nov. (Figs 68D,E, 165D) TYPE LOCALITY. Western Australia (W. of Long L., Wallabi Group. Houtman’s Abrolhos, coll, L. Marsh et al., 27.10.74, holotype WAM 390.75). COLONY. The preserved colony is a fragile, thin sheet, with spicules embedded throughout. A bladder cell layer was not detected on the surface of the colony, and the upper layer of test is thin and fragile, accommodating only a single layer of quite crowded spicules over the zooids. The common cloacal system consists of deep primary canals surrounding clumps of zooids and secondary cavities that penetrate into these clumps at thorax level. The primary cavities extend the whole length of the zooids, sometimes being post-abdominal, and a thin layer of basal test forms the floor of the cavity. The thin surface test is depressed over the deep primary canals. Conspicuously stellate branchial apertures lined with spicules, are evenly distributed over the surface of the colony. Spicules are generally small, not more than 0.03mm diameter with about 9-11 short blunt-tipped rays in optical transverse section, although occasional larger ones (to 0.06mm diameter) have 12-14 long rod-like or almost club-shaped rays in optical transverse section and others, even larger (to 0.125mm diameter) are stellate with 5-7 thick, stumpy conical rays in optical transverse section. Also, fusiform or irregularly branched rods to 0.045mm long, occasionally occur amongst the spherical spicules. ZOOIDS. Zooids in the holotype are about 1.0mm long with contracted thoraces in which it was not possible to determine the number of stigmata. The branchial siphon is short, with rounded lobes and the atrial opening is large and sessile, exposing much of the branchial sac directly to the atrial cavity. An atrial tongue is not present. A long, tapering, strong retractor muscle projects free of the zooid from the upper half of the oesophageal neck. The post-pyloric part of the gut loop is flexed ventrally. A large egg is present at the posterior end of the zooid against the flexed part of the gut loop and a few zooids have a mature testis consisting of 4 large follicles surrounded by 5 coils of a thick vas deferens. Embryos are not present in the test. It is probable that the species is protandrous. REMARKS. The principal distinguishing character is the large stellate spicules with very few rays scattered amongst the others. Other species of Polysyncraton with a similar diversity of spicules crowded throughout the test are P. oceanium and P. magnetae. Generally the majority of spicules in the present species are smaller than in P oceanium, they are about the same size as in P. magnetae but lack the acutely pointed rays that occur in the latter species. Further, in P oceanium a superficial layer of bladder cells obscures the surface depressions over the deep primary cloacal cavities and creates a thicker and firmer surface layer. P. jugosum has small, crowded, stellate spicules and some globular ones together with a few large (to 0.08 diameter) stellate ones. The latter have more rays than the stellate spicules of the present species, and the smaller ones have more pointed rays. 140 Genus Didemnum Savigny, 1816 TYPE SPECIES. Didemnum candidum Savigny, 1816. The genus is characterised by relatively small zooids (often not more than 1mm long); 4 rows of stigmata (seldom with more than 8 per row); a large sessile atrial aperture exposing much of the dorsal surface of the pharynx directly to the cloacal cavity; vas deferens coiled tightly around the testis which usually is undivided or (occasionally) divided into 2 equal halves as in D. himasculum Monniot, 1995, D. bisectatum, D. rubeum Monniot & Monniot, 1996 and D. uturoa Monniot & Monniot, 1987 and a number of species from the northern Pacific Ocean (Romanov, 1989; Sanamyan, 1999. A retractor muscle usually projects from the oesophageal neck of each zooid; and calcareous spicules are present in some or all parts of the test of most species, being entirely absent only in exceptional cases (see D. effusium, D. jedanense). Sometimes a small, often bifid, atrial lip (or tongue) projects from the anterior rim of the atrial aperture. The gut is divided into oesophagus, almost spherical stomach, a duodenal region (often expanded distally), a short posterior stomach and a long rectum. The rectum usually is divided into a roomy proximal chamber and a narrow distal tube separated by a short constriction surrounded by inconspicuous tubules of the gastro-intestinal gland. The relatively short gut loop often has the distal post-pyloric part bent ventrally to form an angle with the proximal part, or even bent up against the proximal part to form a secondary loop. Gonads are dorsal to or (when it is ventrally flexed) posterior to the distal part of the gut loop. The ascending limb of the gut loop often is kinked up anteriorly over the testis. The thoracic body wall musculature consists of fine parietal longitudinal bands extending along each side of the atrial aperture, transverse muscle fibres between the rows of stigmata, a strong dorsal pharyngeal muscle on each side of the dorsal mid-line, a retractor muscle, and a branchial sphincter. D. ficatum is an exception in having an oesophageal constrictor and no retractor muscle. Transverse muscles are not in the parietal body wall. A sphincter muscle surrounds the atrial opening only in D. fucatum, the only Didemnum species known to have a posteriorly placed, circular atrial aperture, altho- ugh it is sessile and does not project ona siphon as in Leptoclinides and most Trididemnum. MEMOIRS OF THE QUEENSLAND MUSEUM In the majority of species, the lateral organ is in the parietal body wall level with the third row of stigmata. Its displacement to positions opposite the second to the fourth rows of stigmata can result from contraction of the body wall muscles, including the upper part of the retractor muscle. When the atrial aperture is open wide the lateral organs appear to project from each side of the opening (from each side of the endostyle). Two or 3 often inconspicuous stolonic test vessels of variable length, each with a terminal bulb-like expansion (ampulla) project from the ventral concavity of the abdomen, opposite the centre of the gut loop (Millar, 1951). Larvae are relatively small, seldom more than Imm, with 4 or 5 pairs of lateral ampullae each side of the 3 antero-median adhesive organs, Ina few species, lateral ampullae are more numerous, 8-10 on each side (D. arancium, D. caesium, D. chartaceum, D. clavum, D. jedanense, D. multispirale, D, precocinum and the Atlantic species D. cineraceum Monniot, 1993). With the exception of D, clavum, D. caesium and D. multispirale in which adult organs are not well advanced in the known larvae, the species listed are amongst the few Didemnum spp. with precocious blastozooids in the larval trunk. D. ossium, the Atlantic species D. ligulum Monniot, 1983, and Indonesian D. guttatum Monniot & Monniot, 1996 and D. linguiferum Monniot & Monniot, 1996 have a corolla of 30 ectodermal ampullae circling the anterior end of the trunk. The larval pharynx has 3 rows of stigmata in the oozooid, but 4 in the blastozooids. Occasionally only 2 adhesive organs are present as in D. albopunctatum, D. parancium, D. pitipiri Monniot & Monniot, 1987, D. poecilomorpha, D. dicolla Monniot, F. & Monniot, C., 1997 from Tanzania, D. maculosum (Milne Edwards, 1841) from the northern Atlantic and D. risirense Nishikawa, 1990 from Japan. Generally the larval trunk is thick and rounded at each end, rather than attenuated posteriorly (where the tail is inserted) as in Trididemnum. Colonies with more than one cloacal system usually are thin, encrusting sheets or extensive irregular masses, their upper surface elevated into rounded or irregular lobes with terminal common cloacal apertures. Regular cushion or vase-shaped colonies each consisting of a single cloacal system with a terminal or central excurrent aperture are known. Some with the latter type of colony are known to clone (subdivide: see D. molle). The surface of Didemnum colonies often is smooth, but THE AUSTRALIAN ASCIDIACEA 4 occasionally minute spicule-filled papillae are crowded on the whole or some parts of the surface between the branchial apertures. In several species ( D, clavum, D. cuculliferum, D. cygnuus, D. membranaceum, D. scopi and D. stragulum )asmall pointed papilla, into which an enlarged ventral lobe of the branchial aperture is inserted, is associated with some or all of the zooids on some or all of the colonies and is pulled down over the openings when the zooid contracts (see also Polysyncraton echinatum). Cloacal systems usually are extensive with relatively shallow 2-dimensional horizontal cavities penetrating the test at thoracic level. Although 3-dimensional cavities (thoracic cavities), extending into large posterior- abdominal spaces behind the zooids, also occur they are not common and are present only in the more bulky, upright colonies, including vase-shaped or lobed ones where cloacal spaces are crossed by test connectives from the surface zooid-bearing layer of the colony to a basal layer ora central test core. Spicules usually are present throughout but sometimes are absent from parts of the colony. Very occasionally the colony is aspicular (e.g. D. effusium, some colonies of D. Jedanense). In D. clavum, D, cuculliferum and D. membranaceum occasional spicules are tetrahedral or have 4—6 narrow pointed rays. Generally spicules have more numerous conical, rounded or rod-like (cylindrical) rays and are stellate, globular, or burr-shaped. Maximum diameter of spicules ranges from 0.02 to about 0.1mm, Bladder cells are present in the test, often in a superficial layer, but sometimes throughout (e.g. D. chartaceum), Living colonies usually are brightly coloured, ranging from red, through orange, yellow, blue, and violet shades, as well as green, black and brown. The pigment occurs in irregular, fusiform to spherical cells in the surface test, mixed with spicules. Pigment usually is lost in preservative. In some species dark spherical cells in larval and adult haemocoel and around the zooids, affect the internal colour of the preserved colonies (see Glossary, haemocoel). Several tropical species have obligate sym- bioses with chlorophyll-containing cells. One of the most commonly encountered, D. molle, with an extensive geographic range from the western Indian Ocean to Fiji between about 26°N and 32°S, has a well established relationship with the prokaryotic alga Prochloron Lewin, 1977, the algal cells being present in the common cloacal 14] cavity. Small, less conspicuous D. efiolum and D. flavoviride, with Prochloron symbionts embedded in the test, are less often recorded — possibly overlooked. Large sheet-like colonies of D. verdantum also may have Prochloron symbionts, although other sheet-like species, D. viride, D, guttatum, D. herba and possibly D. poecilomorpha have a similar symbiosis with cyanophytes in the test. Other tropical species sometimes have patches of non-obligate symbionts, usually Prochloron, on the surtace (Kott et al., 1984). Characters described above are not unique — all occur in one or more genera of the Didemnidae. It is the combination of characters that determine Didemnum. Lissoclinum and Diplosoma, with a straight rather than coiled vas deferens are readily distinguished from Didemnum. Although there are exceptions, Leptoclinides has larger zooids, more fleshy colonies and more extensive posterior abdominal cloacal cavities than Didemnum, and always it has an atrial siphon, and lacks a retractor muscle. Trididemnum zooids also have an undivided testis, a coiled vas deferens and a retractor muscle, but usually (though not always) are smaller than zooids of Didemnum, have only 3 rows of stigmata and usually a posteriorly oriented atrial siphon. Monniot (1995) believes that separation of Polysyncraton (with numerous male follicles) from Didemnum (with the testis undivided or divided into 2) is arbitrary, justified only on practical rather than phylogenetic grounds. This is not a view supported by material examined in the present study. A relatively few Didemnum spp. have some Polysyncraton characters (such as an atrial lip and relatively large zooids, as well as large larvae with 8 or more pairs of ectodermal ampullae and blastozooids). This may be an indication of convergence or even affinity, but not evidence of congeneric taxa. Generally, in Polysyncraton, zooids are larger than those of Didemnum, with fewer and looser coils of the vas deferens, a number of rather loosely associated club-shaped male follicles, adult organs less well developed in the larvae than in Didemnum and other genera and 4 (rather than 3) rows of stigmata in the larval oozooid. Species of Didemnum can be distinguished from each other by the form of the colony and its colonial systems, distribution size and form of spicules, distribution of bladder cells in the test, length of the branchial siphon and shape of 142 branchial lobes, presence or absence of an atrial languet, form of the lateral organ, size of the zooids and number of stigmata, number of coils of the vas deferens, length of the gut and flexure of the posterior pyloric part of the loop. The most reliable characters are the size, form and distribution of spicules. Also significant are the number of larval ectodermal ampullae, and the presence or absence of precocious blastozooids in the larval trunk. However, one of the most variable characters is the size of the larval trunk, intraspecific variations in its length often being recorded, and species determined only on that basis are not reliable. Further, most larvae described from French Polynesia (Monniot & Monniot, 1987) have a larval trunk less than 0.4mm long. It is unlikely that the French Polynesian ascidian population consists only of species with larval trunks less than 0.4mm. It is more likely a characteristic associated with partial isolation of these populations. Didemnum is diverse and cosmopolitan, occurring around all continents, including polar waters, although deep slope or abyssal species are not known. The geographic range of many species is extensive, an Indo-West Pacific range not being unusual for tropical species. Circumpolar species, although less diverse, are well documented for the Southern Ocean (see Kott, 1969). Many of the tropical Australian species have also been recorded from the western Pacific islands including Indonesia. Of the 20 species recorded from French Polynesia only 2 have not been recorded from other western Pacific locations. Only 5 of the 30 species recorded from New Caledonia (Monniot, 1995) are known only from that location. They will very likely be found to occur elsewhere as further collecting is done and new habitats explored. However, it is not likely that larvae are free- swimming for long periods, since sometimes they are found metamorphosing in the parent colony. Gene flow may occur through transport by driftwood and possibly by delayed metamorphosis. Indigenous temperate species abound in Australian waters however (see Glossary, gene flow). Many of the Siboga specimen lots (Sluiter, 1909; Spoel, 1969) have been re-examined and in some cases have been found to consist of more than one species (see Table 3) emphasising the problems of identification. MEMOIRS OF THE QUEENSLAND MUSEUM KEY TO SPECIES OF DIDEMNUM RECORDED FROM AUSTRALIA (‘indicates a temperate species) Atrial aperture small, posterior, and does not expose a large part of the branchial sac directly to the cloacal cavity D. fucatum Atrial aperture large, and exposes a large part of me branchial sactothecloacalcavity........... 2 Green cell symbionts crowded in common cloacal cavity orembeddedintest... 0.0.2... 2.000005 65 Green cell symbionts not crowded in common cloacal cavity orembeddedintest...............- 3 Faecal pellets embedded throughout . . D. psammatode Faecal pellets not embedded throughout... ..... 4 Spicules include elongate bilaterally symmetrical ones with some conspicuously enlarged rays; never aspicular pe eit ols WS ie eye eee oy A D. uturoa Spicules never elongate, bilaterally symmetrical with conspicuously enlarged rays; occasionally aspicular. . 5 Spicules globular or burr-like or if stellate the maximum number of rays 15 or more in optical transverse section; or colonies aspicular Spicules mainly stellate, never with more than 13 rays in optical transverse section; colonies never aspicular . 28 Spicules mostly globular or burr-like with rod-like, fusiform, or irregular rays, or aspicular Spicules mostly stellate with regular conical rays, never ASPIOULAR a. ge ee ag bie sl ae Gay rere 17 Spicule rays thick, 9-11 in optical transverse section; never aspicular D. oblitum sp. nov. Spicule rays thin, more than 11 in optical transverse section; oraspicular. .. 2... 50... ee ee 8 Spicules include some with short points isolated on central sphere; neveraspicular . . D. arancium sp.nov. Spicules do not include any with short points isolated on central sphere; or aspicular 9 Bladder cells in conspicuous spicule-free superficial layer over spicules; 9 coils of vas deferens; never aspibilar.'s 5" .<964 WI Aca. 6 he eG 10 Bladder cells not in a conspicuous spicule-free layer over spicules; less than 9 coils of vas deferens; or aspicular. 11 . Cloacal systems numerous, sheet-like colony with crowded spicules D. albopunctatum Cloacal systems one or 2 in small plate-like colony with SPATSESPICUIES =. 5. p= poet rea ET ee D. hiopaa . Spicules to 0.06mm or more diameter; never aspicular . Atrial tongue present; 6 coils ofthe vas deferens... . . D. precocinum sp. nov. Atrial tongue not present; 8 coils ofthe vas deferens. . . fr ets er Taree oct D. theca sp. nov, Zooids only along each side of circular common cloacal Panala. yk Pes. oy Eke D, jedanense Zooids not only along each side of circular common Gloagalicanals. ope 05 Se es 14 . Coloniesaspicular......... D. effusium sp. nov." Coloniesnotaspicular ... 2.0... .0..000. 15 . Spicules to more than 0.02mm diameter; colony Shieet-like p64 wi a eee ba Reha bas 16 23. Testis subdivided 29, 30. 31. 34. . Spicule rays 17-19 in optical transverse section . . THE AUSTRALIAN ASCIDIACEA 4 Spicules not more than 0.02mm diameter; colon spherical D. monile sp. nov. . Larvae with 4 pairs ofectodermal ampullae . . D. fragile Larvae with 3 pairs ofectodermalampullae...... . D, parancium sp. nov. . Spicules not present throughout colony... ..... 18 Spicules present throughoutcolony.......... 19 . Spicules with more than 19 rays in optical transverse section D. chartaceum Spicules with not more than 19 rays in optical transverse section D. levitas sp. nov. . Common cloacal cavity partly posteriorabdominal. . ._ wae ree age 8 2 eB D. ternerratum sp. nov. Common cloacal cavity never posterior abdominal. . 20 . Spiculesto more than 0.04mm diameter... 2... 21 Spicules never more than 0.04mm diameter... .... : D. bicolor sp.nov. | . Vas deferens coils 12 times. . . . D.jucundum sp.nov." Vas deferens coilslessthanl12times ......... 22 . Spicules include globular ones with flat-tipped rays . 23 Spicules do not include globular ones with flat-tipped rays 25 D. hisectatum sp. nov. Testisnotsubdivided. 2... 2. ee es 24 . Conical spicule rays separated from one another on centralmass ... 0.0.0.0, D. multispirale sp. nov. Conical spicule rays not separated from one another on central mass D, astrum sp.nov. . 26 Spicule rays 13—15 in optical transverse section ... . D. vahatuio 26. Spicule ray-length/diameterratio0.4 . . . D. tabulatum Spicule ray-length/diameterratio less than0.4 . .. . 27 27. Spicule rays all conical; spicule rays never crowded basally D. mutabile Spicule rays not all conical; spicule rays often crowded basally. sen hat ee algo D. lacertosum . Free dark brown spherical cells present around zooids Loe BN ae Bae ES 8p ot A MEA SO 29 Spherical vesicles interrupt spicules around branchial apertures D. spadix sp. nov. Spherical vesicles do not interrupt spicules around branchialapertures... 2.2... ..0- 2044 ee 30 Spicules to more than 0.07mm diameter .. . D.fuscum Spicules not more than0,07mm diameter... ..... Nesee tk QL ae. D. sordidum sp. nov. Occasional giant spicules with a total of 4-6 rays present 2 Occasional giant spicule with a total of 4-6 rays not PRESEN, oo ape ote ae ha Beas WM qa wee aie debeat Wl le dob a's Me 35 . Giant spicules with broad-based conicalrays ..... ost Lic 4th 5 t sept D. complexum sp. nov." Giant spicules with longspikyrays.......... 33 . Stigmata6inanteriorrow. 2.2.2.0. .0.0.. 34 Stigmata 9 in anterior row D. clavum sp. nov, Spicules to 0.06mm diameter with conical pointed rays; vas deferens with 6 coils; ray length/spicule diameter ratio 0.3 or less D. membranaceum 35. 36. 37. 39, 40, 4] 42. 43. 44, 45, 46, 47, 48. 49, 143 Spicules not more than 0.04mm diameter with rod-like blunt-tipped rays; vas deferens with 8 coils; ray length/spicule diameter ratio 0.4... . D. cuculliferum Spicules sparse in or absent from appreciable parts of the cOlotiy i: BRAT eA jon ce Ly SP 36 Spicules not sparse in or absent from appreciable parts of Hie cGlonty :, a4 nt lt Mea ye Richie see 43 Colonies upright lobes with terminal common cloacal apertures; posterior abdominal cavities always present Noe eee A! leet als ae aie AL ope sks ae at ME td aw Bs aa 37 Colonies not upright lobes with terminal common cloacal apertures; posterior abdominal cavities not always PRESEN Aedes: deren nied ep) APs oe es 41 Spicules all less than0.07mm diameter... 2... . 38 Spicules notall less than 0,.07mm diameter... . . . 39 . Spicule rays to 13 in optical transverse section; larval trunk 0.9mm long with 6 ectodermal ampullae per side a A Ly Paes Pe oe rn D. fragum sp. nov. J Spicule rays to 11 in optical transverse sections; larval trunk 0.5mm long with 5 ectodermal ampullae per side. a ea re ar ered oy = D. pecten sp. nov. Branchial siphon about half the length of the thorax or more; 12 or more larval ectodermal ampullae per side .. D. pellucidum sp. nov. Branchial siphon less than half the length of the thorax; fewer than 12 larval ectodermal ampullae per side. . 40 Spicules to more than 0.1mm diameter and 9-11 rays in optical transverse section, .. . . D, sucosum sp. nov. Spicules not more than 0.1mm diameter and 7—9 rays in optical transverse section... ........ D. roberti . Dark pigment persists in surface of preserved specimens; common cloacal cavity thoracic only... . D. caesium Dark pigment not present in surface of preserved specimens; common cavity notonly thoracic ... . 42 Zooids in ligament between surface and basal test. . . . One ES ce eg D, linatum sp. nov. Zooids in double series along each side of circular cloacal OANAlSe escent D. evygnuus sp. nov. Colony asingle cloacal system . D. minisculum sp.nov." Colony nota single cloacal system 44 Cloacal cavities include posterior abdominal component oe ee ee ee 45 Cloacal cavities do not include posterior abdominal COMPONCN: 44 ncaa HP ee eR 49 Branchial siphons about half the length of the thorax . . a Rege sh Po tteiad Ew Bile a far et D. elongatum Branchial siphons significantly less than half the length of the thorax 46 Colonies sheet-like; lateral organ flap-like it of: Wate s aod LAG D. crescente sp, nov, 7 Colonies usually lobed, branched forming complex reticulum; lateral organ not flap-like. .. 2.2... 47 Spicules with conical rays only 48 Outer surface with vertical toothedridges. ....... ee ba ane Ft SR ng Te eye D. spongioide adit sate « D. lissoclinum sp. nov.' Bladder cell layer containing dark pigment conspicuous on surface D. grande Bladder cell layer containing dark pigment not conspicuous on surface 50 144 40. 55, 56. ah oo 60. 66, 07, 6X, 69, . Vasdeferens coils | | times aroundtestis . _ Vas deferens with 9 coils . Vasdeterenscoils 7 times... . . Spiculesto 0.9mm diameterormare. 2... Spicules not more than 0.07010 diameter 33 . Branchial aperures cach assovited wilh a pointed surface papillis De Straggeilum sp. ny, Branebial apertures not associated with a pointed surfuce papilla... 2k yas , 32 » Atrial lip present: some spicules with blunt or truncated yays present 0D, inveterarium sp. n0Vv. Atrial lip not a spieule rays never blunt or frincated D. micrathoracicum sp. n0y, _ Surface marked off into palyjonal areas by depressions ad over primary clogeal canals. Surface not murked off inlo polygonal areas by depressions over primary cloncalcanals.... .. 4 58 ~ Branchial avons lenppethan half the length of the thorax . D. macrosiphoniun sp.nov. Brunchial spbons not longer than half the wie of = thorax, . ~~ - Spicules of 2 yes, some with rod-like rays, pert 320) Ss Lo an eS ae D. tanga Spicules NoLof2 types. conical rays only present... 36 Ray lungth/spicule diameter raliomore than 0,3... 37 Ray length /spicule diameter ratio less than 0,3 «ag D, paraluen 2D. viersp. nov. Vas delerens cuils 9 limes orlessaround testis, 5. + its . Do mantilesp. nov. : Spitinles ‘mostly er atily with cond like rayf. 0... 39 Spicules not mostly oroaly with rod-like rays. . Spicules.wilh 9 or more mays ist optical Iunisverse section : D, scoprsp. my, Spicules never with more than O rays IN optical transverse OHLONE ot et eae wee 1) at eke = D_candidum Spicules with rounded and pointed conical rays und appreciable numbers of globular ones, 1) mosalevi ypepneces Spicules rays mystly pointed conigul-raysonly . . . . 41 . SpiculestoW04mmdiameterorless .. 2... ... 62 Spicules to more than Q.04mim diameter .. 2... 63 Vas deferens with 6cuils D.delectnm' sepe Spicule raysto Lin ppticaitransverse sectibn, edt D, vulgare sp, nov, Spicule raysto 9 or lessin optical transverse section... , OF D. perplexum sp. poy, . Do granilatin Cr ee oe VasdeferenscoilsGtimes ... . . Spicules globular orburrlike only... 0.0. 02. 66 Spicules notenly globular or hurr-like 67 Colony upright, vuse-shuped, conspicuous quantity oF mucus secreted when disturbed D, malle Colony hot upright, vase-shaped? mucus not secreted when disturbed : D flaveviride Colonies srnall, tnconspictons witha has system tae . Defiotam Colonies lurge, sheet-like with puimarend sy rating _. 68 Bronchial siphon halfthe length ofthe thorax ormore — 69 Branchial siphon less than halfthe length ofthe thorax. 71 Spicules willyblunt-Lipped as wells conical rays... 70 Spicules only with pointed conical rays. . “ D, herbirsp. nov. ee ee er MLUMGIRS OF TLE QUEENSLAND MUSEUM 70, Spicule rays 911 in optical transverse section D. gruittatum Spiculerays |) 13 in optical transverse section , D, peecilomarpiia 1) viride . PD verdant sp.nov, 71, Spicule rays conical \ Spicule mys rod-like , The following species known in adjacent areas are not yet recorded from Australian waters: Didenmium apurora Mouniot & Monniot, 1987 (but not 1996); and Mooniot (1995), has groups of zooids. in unusual fused capsules of test and spicules. Spicules are up to about 0.03mm diameter, some with flat tipped truncated rays and others with pointed conical rays, 7-9 in optical wansverse section, The vas deferens coils 6 times. The spicules resemble those of D. eliffiatdum Monniot, 1995 (> D. apurote: Monmot & Monniot, 1996), and the temperate D. hicolor The former has mose coils of the vas deferens (9) and the colonies are lobed with terminal common cloacal apertures. The latter has different cloacal systems from the present species. The blister-like capsules protruding Irom the surface occur in some speciinens of 2, fragife and they may have pathological rather than genetic Significance. Didemmumn bimasculwy Monniot, 1995 from New Caledonia have targe (to 0.1mm diameter) spicules with 5-7 relatively short conical pointed rays in optical transverse section. The ray length/spicule diameter ratio is about 0.28, Although spicules resemble those of D euesium and D. grande, the present species has a characteristic 2- lobed testis, laryae with 4 bifid ampullae on each side and green plant cells, probably in obligate symbiosis, embedded in the test and in the cloacal cavity. The other species with 2 male follicles recorded from this region are D. reetrvetwn Sluiter, 1909 (and possible synonyms 1) ryheuwn Monniot & Monniot. 1996 and D. Jraile Shuiter, 1909 part, ZMA TU446.2) which bas small globular spicules with numerous rod-like rays: D. hisectedum and specimens from Kiribati assigned to D. candid: Vokioka, 1967 with many ray's on the stellate spicules: and D. wurea (with unusual enlarged spicule mays). Didemnum brevioris Monniot, F. & Monniot. C., 1997 fromm the western Indian Ocean, has brown zoords with dark squamous epithelium possibly like those of D. alho- punctatun, Che small globular spicules mast closely resemble those of D. oblinam. However, the species. is distinguished by its simall larval trunk (0.4mm long) with oozooid and blastozooid, Didemnum captivum Monniot, F. & Monniot, C,, 1997 from Tanzania, has a relatively large branchial sac with & stigmata in the anterior row, and possibly § coils of the vas deferens. The spicules with 7-9 conical rays to 0.04mm diameter resemble those of D. candice trom which it is distinguished by its 8 or 9 larval ectodermal ampullae per side and larval trunk 0.6mm long. D. perplexwn is distinguished only by having fewer larval lateral ampullae and only 7 coils of the vas deferens. D, granulaninralso has similar spicules but only 6 vas deferens coils and smaller larvae with 4 ectodermal ampullae per side, THE AUSTRALIAN ASCIDIACEA 4 Didemnum contortum Monniot, F. & Monniot, C., 1997 from Tanzania has spicules about the same size ( to ().03mm diameter) and form (with 17-19 pointed rays) as those of D. tabulatum. The species are distinguished by the more open cloacal systems in the Tanzanian species. In D. contortum, the common cloacal apertures are on the elevations formed by thickening of the sponge-like basal test which is filled with spicules and interrupted by cavities. Clumps of zooids are contained in test strands that interrupt a large common cloacal cavity and connect surface to basal test. The common cloacal cavity penetrates amongst the zooids at thoracic level. The zooids have a coiled vas deferens and a forked atrial lip. The cloacal systems resemble those of Lissoclinum spp., and some other species of Didemnum (e.g. the temperate D. lissoclinum and D. ossium, and D. roberti and D. spongioide from northern Australia), which have larger spicules with fewer rays than D. contortum, Didemnum dealbatum Sluiter, 1909 trom Indonesia was reported to be a fleshy irregular mass on sand and coral with a smooth upper surface and spherical spicules in the upper and lower layers of test (Sluiter, 1909). On re- examination, one of the syntype lots (ZMA TU44 1.1) was found to contain 2 colonies of a species of Didemnum and the other specimens (ZMA TU441.2), previously thought to be syntypes of the present species, were found to be 2 colonies of ZT. miniatum Kott, 1977 —small, soft, irregular colonies with rounded margins, minute zooids with 3-rows of about 7 stigmata, small larvae with the trunk surrounded by a coat of embedded symbionts, and globular spicules to 0.035mm diameter (but generally smaller). Thus only ZMA TU441.1 colonies constitute the syntypes of D. dealbatum (Spoel, 1969: pl. | fig 6). They are extensive flat sheets with an even upper surface stiff with crowded spicules. The upper surface is slightly wrinkled in preservative probably owing to the natural elasticity of the colony after its removal from the substrate. Another thin layer of spicules is on the base of the colony, but spicules are absent between. The spicules are stellate, up to 0.04mm diameter with about 11—13 longitudinally striated, sometimes pointed, rays in transverse optical section. Spicules are similar to but significantly smaller than those of D., astrum, which has similar cloacal cavities with zooids in clumps surrounded by deep cloacal cavities and some shallow secondary cloacal spaces at thoracic level, although in the latter species spicules are in a thicker layer inthe upper part of the colony. The colonies look rather like Leptoclinides brandi owing, to the stiff slightly wrinkled surface test over the gelatinous spicule-free test in the centre of the colony. Didemnum dicolla Monniot, F. & Monniot, C., 1997 from Tanzania has thin encrusting colonies with shallow thoracic common cloacal cavities. Spicules are to 0.05mm diameter and have 9-11 pointed or truncated rays in optical transverse section. Zooids have a distinct double gut loop and 5 coils of the vas deferens. The larva has only 2 adhesive organs and 6 or 7 lateral ampullae on each side. Both common cloacal systems and spicules resemble those of D. apuroto Monniot & Moniot, 1987 and D. diffimdum Monniot, 1995, but both these species have only 4 larval 145 ectodermal ampullae (rather than 7 or 8 per side), 3 adhesive organs and more coils of the vas deferens. D. albopunctatum, D. parancium, D. pitipiri and sometimes D. poecilomorpha with only 2 larval adhesive organs have different spicules. Didemnum diffiundum Monniot, 1995 (> D. apuroto: Monniot & Monniot, 1996) from New Caledonia has spicules to 0.03 diameter with pointed as well as truncated rays that resemble those of D. bicolor but with fewer rays. Unlike D. apuroto (which also has similar spicules), D. diffundum has 9 coils of the vas deferens. D. inveteratum and D. ossium have similar but larger spicules than the present species. Didemnum digestum Sluiter, 1909 from Indonesia, Fiji (Kott, 1981) and French Polynesia (Monniot & Monniot, 1987) resembles D. uturoa in the | to 3 enlarged rays on many of the spicules. Kott (1981) re-examined the spicules of the paralectotype of Sluiter’s species (ZMA TU442.2) and found many of the spicules to have stumpy conical rays in polygonal bases in addition to the | or 2 large tapering rays; others are stellate with only 5-7 conical pointed rays in optical transverse section. Burr-like shapes with relatively numerous rays dominate the spicules of D. uturoa, The spicules of D. digestuwm are larger than D. uturoa, being up to 0.055mm in diameter. Didemnum lambitum Michaelsen, 1924 from New Zealand resembles D. fragum from southern Australia in the large conical colonies with terminal common cloacal apertures and is distinguished from it principally by its shorter branchial siphon, 10 (rather than 12) coils of the vas deferens and 4 (rather than 6) larval ectodermal ampullae. Didemnum ligulum: Monniot & Monniot, 1987 (part: flat, rose-coloured colonies) from French Polynesia is possibly an undescribed species with zooids grouped around a central aperture forming separate cloacal systems isolated from one another by narrow circles of zooid-free test. They resemble the isolated systems of Polysyncraton glaucum trom which the French Polynesian specimens are distinguished by generic characters (gonads) and spicules (to 0.06mm diameter) with more (13 to 15 in optical transverse section), long and pointed, as well as truncated, rays. Spicules also distinguish the present species from the Atlantic nominal species (Monniot, 1983) and other specimens from French Polynesia (D. arancium) which Monniot & Monniot (1987) had thought were conspecific. The latter has small globular or burr-like spicules with numerous short points. The spicules resemble and are the same size as the spicules of D. ossium (>D. ligulum: Monniot, 1995) and D. astrum, but the cloacal systems are all different. Larvae are not known. Didenmum linguiferum Monniot & Monniot, 1996 has thin, encrusting colonies with a red and white marbled surface, extensive thoracic common cloacal spaces, spicules crowded throughout, short branchial siphons, narrow thoraces, 6 stigmata in the anterior rows, 6 coils of the vas deferens, long (0.8mm) larval trunk with a circle of about 30 ampullae around the median adhesive organs and large (to 0.08mm diameter) stellate spicules with 15-17 conical points in optical transverse section. The spicules 146 TABLE 3. Siboga Expedition Didemnum spp. assigned by Sluiter ( 1909) and re-examined in the course of the present study. MEMOIRS OF THE QUEENSLAND MUSEUM Species assignation Specimen lot Revised assignation F ZMA teg. no. F (Sluiter, 1909) (Spoel, 1969) (this work) D. albopunctatum TU433.1 Didemnum perplexum sp. nov. TU433.2 lectotype Didemnnum albopunctatum TU433.3 Didemnum nultispirale sp. nov. + D. jedanense TU433.4 Didemnum jedanense D. caesium TU434 holotype Didemnum caesium D. chartaceum TU437 syntypes Didemnum chartaceum D. cuculliferum TU490 holotype Didemnum cuculliferum D. cuspidatum TU440.1 syntypes Leptoclinides cuspidatus TU440.2 syntypes Leptoclinides cuspidatus D. dealbatum TU441 ayntypes Didemnum dealbatum TU441.2 rididemum miniatum D. digestum TU442.1 Didemnum multispirale sp, nov. TU442.2 paralectotype Didemnum digestum D. dispersum TU443.1 syntypes Trididemnum dispersum TU443.2 syntypes Trididemnum dispersum D. elongatum U444 syntypes Didemnum elongatum TU445 syntypes Didemnum elongatum D. fragile TU446.1A ?Didemnum precocinum sp, nov. TU446.1B Syonypes Didemnum fragile TU446.2 ?Didemnum recurvatum D. fucatus TU448 syntypes Didemnum fucatum D. jedanense TU454.1 lectotype Didemnum jedanense TU454.2 Didemnum perplexum sp. nov. TU454.3 Didemnum multispirale sp. nov. D. makropnous TU461.2 Didemnum perplexum sp. nov. TU461.3 Didemnum grande TU461.4 Didemnum grande TU461.5 Didemnum grande TU461.6 Didemnum stragulum sp. nov. D. membranaceum TU471.1 lectotype Didemnum membranaceum TU471.2 Didemnum clavum sp. nov. D. ramosum TU1271 aralectotype Trididemnum sibogae (nom. nov. for Didemnum ramosum) TU476.1 2 TU476 Trididemnum Pe oneal! 4 sp. nov. TU476.3 lectotype Trididemnum sibogae D. reticulatum TU475.1 Leptoclinides rufus TU475.2 Leptoclinides rufus TU475.3 Leptoclinides marmoratus TU475.4 lech pe Didemnum reticulatum D, megasterix Monniot, 1995, part, specimen from the north) although the larvae are larger and have a blastozooid. D. nocturnum Monniot, F, & Monniot, C., 1997 has a similar larva but smaller spicules. Didemnum nigricans Monniot, 1995 from New Caledonia has crowded spicules to about 0.045mm diameter. Its small zooids and surface test become brown after fixation like D. albopunctatum and D. fiuscum, but the spicules have markedly conical rays that distinguish it. Its spicules are similar to D. perplexum but it has more (9) vas deferens coils and 5 rather than 6 pairs of larval epidermal ampullae, Didemnum nocturnum Monniot, F. & Monniot, C., 1997 from Tanzania, is a deep blue in life (lighter patches where spicules are more crowded) and is brown in preservative. Zooids are in clumps surrounded by deep primary common cloacal canals. They have 6 or 9 (figs 6c, and 6d, respectively: Monniot, F, & Monniot, C., 1997) coils of the vas deferens and 10 stigmata in the anterior row. Spicules are stellate to 0.04mm diameter with 9-11 sturdy conical rays in optical transverse section. The larval trunk is 1.0mm long and has 8 or 9 lateral ampullae per side and a blastozooid, The maximum spicule size recorded is smaller than is usual for D. caesium although they are of similar form, as are the zooids and the colony (including its pigmentation), Larvae are larger in the present species and have a blastozooid — not reported in D. caesium. The present species has larvae like those of D. megasterix Monniot, 1995 (part, specimens from the south) but slightly larger, and the maximum spicule diameter is much less than the latter species. Didemnum paa Monniot & Monniot, 1987 forms thin, white, pale-rose or yellow plates. Spicules (to 0.055mm diameter with 11-13 short conical points in optical transverse section) are crowded throughout. Spicules resemble those of D. mutabile Monniot & Monniot, 1987, from which D, paa is distinguished by its large number (10) of vas deferens coils and more numerous spicule rays (see also Monniot, 1995). Didennum parau Monniot & Monniot, 1987 from French Polynesia and the Phillipines (newly recorded 147 colony QM G302912) forms thin, fragile, white colonies. Spicules (to 0.03mm diameter) are present throughout and have narrow, rod-like rays like those of D. albopunctatum and D. fragile. The post-pyloric part of the gut loop is flexed to form a double loop, the vas deferens coils 7 times, and the larval trunk is 0.37mm long with 4 lateral ampullae oneach side. D. fragile has a brittle sheet-like colony, larger larvae (the larval trunk being about 0.45—0,5mm long), slightly larger spicules, and only 6 vas deferens coils. D. albopunctatum has more vas deferens coils. Didemnum perlucidum: Monniot & Monniot, 1987 from French Polynesia and New Caledonia (Monniot, 1995) was assigned to the Atlantic Ocean species, D. perlucidum Monniot, 1983. Specimens from New Caledonia have 7 or 8 (?) coils of the vas deferens and small spicules (to 0.03mm diameter) with 5—7 conical rays in optical transverse section, The larval trunk is 0.45mm long, the same length as the nominal Atlantic species, but it is much less spherical and its tail is wound only two-thirds of the way around it (rather than completely encircling it). The species are most likely distinct from one another. The Pacific Ocean specimens resemble D. perplexwm in the number of coils of the vas deferens and in the number of spicule rays but it differs in having only 4 pairs of larval epidermal ampullae (rather than 6 pairs) and smaller spicules. Its small spicules are a similar size to those of D. granulatum but it has fewer and possibly shorter spicule rays. However, the spicules of the western Pacific material have not been adequately described. Didemnum pitipiri Monniot & Monniot, 1987 and Monniot, 1995 forms pale yellow encrusting colonies. The species has few unique characters. The spicules (to 0,03mm diameter) resemble D. mutabile, most having numerous (15-17) short conical rays and some having longer almost fusiform ones. The small larval trunk (0.33mm long) with 2 adhesive organs (from the type specimen) and the occasional larger spicules with fewer, larger rays, distinguish the species. D. maculosum from the north eastern Atlantic (see D. candidtm, Remarks below), Didemnum albopunctatum, some D. parancium and D. poecilomorpha have only 2 adhesive organs, but are distinguished from the present species by many characters. D. linguiferum Monniot, 1985 has spicules of similar form to D. pitipiri but they are larger (to 0.08mm diameter). Didemnum recurvatum Sluiter, 1909 (holotype ZMA TU474; Millar, 1975; Polvsyncraton recurvatum: Kott, 1981) and Didemmum sp. (part, D. fragilis Sluiter, ZMA TU446.2) both from Indonesia, have hard cushion to sheet-like colonies, globular spicules to 0.03mm diameter, horizontal thoracic cloacal spaces, a retractor muscle from halfway down the oesophagus, about 8 stigmata per row, 5 coils of the vas deferens around 2 testis follicles, the post pyloric part of the gut loop bent at right angles and slightly twisted to the right and a large (about 0.8mm long) trunk with 4 pairs of lateral ampullae. Kott (1981) reported D. recurvatum to have been a distinctive dirty brownish colour in preservative owing to pigment cells in the surface. D. bimasculum Monniot, 1995 and D. rubeum Monniot & Monniot, 1996 also have a 2-lobed testis but they have symbiotic plant cells, Other forms with 2 male follicles 148 described from the western Pacific are D. uturoa Monniot & Monniot, 1987, D. candidum: Tokioka, 1967 (from Kiribati) and D. bisectatum, all readily distinguished by their spicules (see D. fragile, Remarks below). D. precocinum has smaller zooids, similar but larger spicules, undivided testis and a larval blastozooid and it lacks the pigmentation of the present species. Didemnum rubeum Monniot & Monniot, 1996 from Chuuk Atoll and Palau Is has bright red to pinkish encrusting sheet-like colonies with globular spicules, 2-lobed testes, and large larvae and is reported to have symbiotic algae in the surface test and colonies that become green in preservative. It resembes D, recurvatum although symbiotic cells have not been reported in that species. D.bimasculum Monniot, 1995 has symbiotic cells and a 2-lobed testis, but has large stellate spicules to 0.1mm diameter. D. viride also is green in preservative, but lacks the globular spicules and 2-lobed testis. Didenmuni stercoratum Monniot & Monniot, 1996 from the Philippines forms soft, thin encrusting sheets, tan or yellow in life and white in preservative. The surface is marked into polygonal areas by depressions over the primary cloacal canals which have zooids along each side, Secondary cloacal cavities penetrate in amongst the clumped zooids surrounded by the primary canals. The 7 coils of the vas deferens and spicules (to 0.04mm diameter) are similar to those of D. jedanense, from which this species is distinguished by its lack of pigment, smaller larvae without blastozooids and smaller zooids. The species is one of the few reported to have faecal pellets in the basal test (see Trididemnum savignii). Didemnum toafene Monniot & Monniot, 1987 from French Polynesia and New Caledonia (Monniot, 1995) has irregular, thin encrusting colonies. Spicules are crowded throughout, They are reported to 0.05mm diameter with 7-9 blunt conical rays in optical transverse section. Large spicules to (at least?) 0.08mm diameter with pointed rays of variable lengths are present, although the maximum diameter of these large spicules is not recorded. Zooids are less than Imm long, 6 stigmata are in the anterior row, the retractor muscle projects from halfway down the oesophageal neck, 11 coils of the vas deferens surround the testis, and the larval trunk is 0.3mm long with 4 pairs of epidermal ampullae. The thin hard colonies resemble those of D. inveteratum sp. nov. but the zooids lack the atrial tongue of the latter species, and have more vas deferens coils, fewer spicule rays and generally smaller spicules. The larger spicules have more numerous rays than the tetrahedral giant spicules of D. membranaceum. Didemnum albopunctatum Sluiter, 1909 (Figs 69, 165H; Pl. 7A,B) Didemnum albopunctatum Sluiter, 1909; 58 (part, specimens from Ambon anchorage statn 231 only). Kott, 1981: 162, Didemnum biglutinum Monniot, 1995: 300. Monniot & Monniot, 1996: 152. NEW RECORDS. Queensland (Capricorn Group QM G308031-2 G308172; ? Swain Reefs, QM G308372; Whitsunday Is, QM GH5367). MEMOIRS OF THE QUEENSLAND MUSEUM PREVIOUSLY RECORDED. Indonesia (Ambon —ZMA TU433.2 lectotype Sluiter, 1909). Fiji (Kott, 1981). New Caledonia (Monniot, 1995), Palau Is (Monniot & Monniot, 1996). COLONY. Colonies are firm, flat encrusting sheets, irregular in outline, with rounded borders and only 2—3mm thick. The surface always is smooth, with a thin bladder cell layer super- ficially and beneath that the small white calcareous spicules are crowded throughout the test — in the basal test, and in the sheaths of test associated with the zooids as they cross the cloacal cavities. The branchial apertures sometimes appear as dimples in the surface of the colony, and sometimes a clump of spicules is seen in the siphon. Spicules are small (to 0.03mm diameter), relatively uniform, burr-like with crowded, flat- or round-tipped, long, narrow rod-like rays. The common cloacal cavity surrounds the thorax of each zooid with its narrow ventral sheath of test that connects surface to basal test. Abdomina remain in clumps, each clump surrounded by deeper cloacal cavities that extend the whole length of the zooids, or they are embedded in the basal test. Large common cloacal apertures are randomly distributed over the surface. Sometimes radial ridges crowded with spicules are in the roof of the cloacal cavity around each opening. In preservative the colonies are beige to white, with brown pigment in the superficial bladder cell layer, colourless thoraces and yellow to white abdomina, In life, however, they were magenta* (QM G308172) or black-grey* (QM GH5367), with spherical red pigment cells in the superficial bladder cell layer, and red zooids. Type colonies and those recorded from Fiji (Kott, 1981) are said to have been dark to purple in life, although colonies from Palau were a greenish colour (Monniot & Monniot, 1996) and those from New Caledonia were brown (Monniot, 1995). ZOOIDS., Zooids are small (barely more than Imm), with a short branchial siphon and 6 well-formed rounded lobes around the aperture. The specimen (QM G308372) from the Swain Reefs has black squamous epithelum in the body wall of both thorax and abdomen, especially conspicuous around the anterior end of the zooid. The atrial aperture is large and open, exposing the whole dorsal surface of the branchial sac to the cloacal cavity, and it has a small anterior atrial lip which is inserted into the surface test and often is torn when the zooid is removed. Eight stigmata are in the 2 anterior rows, 7 are in the third row, THE AUSTRALIAN ASCIDIACEA 4 and 6 are in the posterior row. A short and thick to long and fine retractor muscle extends from the anterior part of the oesophagus out into the abdominal test sheath or basal test. The gut is long, the distal part of the loop bent up into a secondary loop. Nine spirals of the vas deferens surround the outer surface of the hemispherical testis. Larvae are present in the basal test of a colony (QM G308172) collected in March from the Capricorn Group. The tail curves a little more than three-quarters of the way around the trunk which is 0.5mm long. Four lateral ampullae, are along each side of only 2 median adhesive organs in the fully developed larva. REMARKS, Preserved specimens assigned by Sluiter to this species have brown pigment in spherical to oval cells in the superficial test as reported for some of the newly recorded specimens. Spicules are not present in the test around the rims of the numerous sessile common cloacal openings. However, the spicules in each of Sluiter’s specimens are different. The one that conforms with the species description (ZMA TU433.2) is proposed as the lectotype. Different species are represented by each of the other specimens (see Table 3). Sluiter (1909) described the spicules of the present species as being spherical (up to 0.043mm diameter) with radially arranged needle-like rays terminating in small points. Although some of the spicule rays of the present species have irregular tips and are not strictly flat-ended, the majority of them are. The pointed rays that Sluiter reports are in specimens inadvertently assigned to the species — viz. ZMA TU433.1 (D. perplexum), TU433.3 (part, D. multispirale), TU433.3 (part, D. jedanense) and TU433.4 (D. jedanense). Didemnum fragile is a closely related species that lacks the dark pigment, has only 6 coils of the vas deferens and larvae with 3 (rather than 2) adhesive organs and shorter tails. The present species has spicules that resemble those of D. precocinum from which it is distinguished by its thin bladder cell layer, dark pigment in the test, hemispherical testis with 9 coils of the vas deferens and its larvae. D. dealbatum Sluiter, 1909 has spicules the same size and shape as the present species, but they are not present in the middle gelatinous layer of test. D. hiopaa has similar spicules and similar zooids with the same number of vas deferens coils, but its colonies are small, the test is soft and transparent and the spicules are only sparsely distributed. 149 FIG, 69. Didemnum albopunctatum (A, QM G308032; B,C, QM G308172) — A, thorax; B, abdomen; C, larva. Scales: 0.1mm. Didemnum biglutinum Monniot, 1995 from New Caledonia and the Palau Is (Monniot & Monniot, 1996) has the same gelatinous surface layer of bladder cells over a layer of brown pigment mixed with spherical black particles, small burr-like spicules crowded in the remainder of the test, and clumps of zooids surrounded by deep common cloacal canals, as Sluiter (1909) recorded for the type material. The larva, like the present species, has only 2 adhesive organs, 4 sets of lateral ampullae and a long tail; and the zooid has a similar number of vas deferens coils. This species and D. albopunctatum appear to be synonymous. The black squamous epithelium in the body wall of the light grey specimen from the Swain Reefs (QM G308372) has not been reported previously in this species. Otherwise the specimen resembles others assigned to the present species. Dark squamous epithelium occurs commonly in Diplosoma and Trididemnum (see Glossary). Didemnum arancium sp. noy. (Figs 70, 166F; Pl. 7C,D) Didemnum ligulum: Monniot & Monniot, 1987: 34 (part, orange colonies from French Polynesia). TYPE LOCALITY. Queensland (Wistari Reef, low tide rubble fauna, coll. P. Kott 4.3.93, holotype QM G308115; Heron [., eastern end, rubble fauna, coll. P. Kott 9.3.93, paratype QM G308120). FURTHER RECORDS. Queensland (Heron I., QM G308096, G308127, G308144, G308210, G308218, G308223, G308260, G308317, G308334; Swain Reefs, G305374, G308435-7). PREVIOUSLY RECORDED. French Polynesia (Monniot & Monniot, 1987). COLONY. Thin, sheet-like encrusting colonies have a hard, smooth surface, interrupted sometimes by slightly protuberant branchial apertures, with rows of spicules around the margins of the stellate openings. Spicules are only moderately crowded in the middle layer of test but are crowded in a basal layer of the colony and in a thin surface layer which is raspy to the touch. There is no spicule-free superficial layer of bladder cells. The cloacal cavity is thoracic, each thorax crossing it in association with a ventral sheath of test that joins the surface test to the basal test in which abdomina are embedded. Large, sessile common cloacal apertures randomly distributed over the surface lack spicules around the rims. Most spicules are burr-like with numerous (to 21) long, rod- or needle-like rays with flat to chisel-shaped tips. Others have more numerous (up to 27 in optical transverse section) very short conical rays set in concavities in the central mass of the spicule. The latter are sometimes quite rare. Both types are up to 0.05mm in diameter and very occasionally to 007mm, but are more often in the vicinity of 0.02—0.04mm. In life, colonies are salmon coloured", or buff pink® (a yellow colour), or orange- -rufus*, or orange vermilion" to saturn red* (a deep orange colour). Zooids are orpiment-orange* or scarlet vermilion®, and larvae being incubated in the test are orange-chrome*. Orange zooids are often visible through the thin layer of surface test, and the colonies look spotted. In preservative colonies are apricot with bright orange zooids at first, but they fade to white, with yellow to yellow-beige zooids sometimes with a greenish gut and often some yellowish pigment in the basal test. Prochloron sometimes is on the surface, and in branchial siphons. ZOOIDS. Zooids are moderately large, the extended thorax and abdomen together being MEMOIRS OF THE QUEENSLAND MUSEUM about 1.3mm. The rim of the branchial aperture is divided into 6 triangular lobes. An atrial tongue, of variable length, extends from the anterior rim of the opening and usually is bifid at the tip. Often this is torn off as the zooid is removed from the test. The atrial aperture is wide, exposing most of the pharynx directly to the cloacal cavity, Eight stigmata are in the first 3 rows of stigmata, and 6 are in the posterior row. They are long and rounded at each end. The gut loop is open, its ascending limb bent ventrally behind the testis, which is large and oval or dome-shaped with the vas deferens spiralling 7 times around its outer half. The long, thin retractor muscle is free from the anterior part of the oesophagus. Embryos are being incubated in the basal test of both holotype and paratype. The larval trunk is 0.6mm long with the tail wound three quarters of the distance around the trunk. Ten lateral ampullae are on each side of the antero-median row of 3 adhesive organs. An oozooid with 7 stigmata in each of 3 rows and one blastozooid with 4 rows of stigmata are in the trunk. REMARKS. The long atrial tongue, the numerous larval lateral ampullae, and the larval blastozooid also occur in D. chartaceum, D. levitas , D. jedanense and D. precocinum, from which the present species is distinguished by its spicules and by colony colour. D. caesium and D. multispirale which have a similar number of larval ectodermal ampullae (although a blasto- zooid may not be present), also are distinguished by their spicules. The atrial tongue, large number of larval lateral ampullae and larval blastozooids are reminiscent of, but do not necessarily indicate affinity with Polysyncraton. Didemnum ligulum: Monniot & Monniot, 1987 apparently consists of 2 separate species, distinguished by differences in colony form and spicules. Neither of these species can be assigned to D. ligulum Monniot, 1983 from Guadeloupe which has significantly larger larvae (more than 0.8mm long) with more lateral ampullae, fewer stigmata, larger spicules with numerous but not crowded conical rays (like some from D. multispirale), and 6 coils of the vas deferens. The only thing that all the colonies assigned to D. ligulum: Monniot & Monniot, 1987 have in common with D. Jigu/um Monniot, 1983 is a forked atrial tongue (like, D. albopunctatum, D. caesium, D, chartaceum, D. multispirale, and D. ossium). D. ligulum: Monniot, 1995 from New Caledonia also is a different species from either THE AUSTRALIAN ASCIDIACEA 4 FIG, 70. Didemnum arancium sp. nov. (A, QM G308096; B,C, QM G308115)—A, thorax; B, abdomen showing gonads and gut loop; C, larva with thoracic blastozooid. Scales: 0.1mm. the present one or the rose-coloured flat colonies from French Polynesia (assigned to the same nominal species; see Didemnum ossium). The thicker orange colonies from French Polynesia (Monniot & Monniot, 1987) are the same colour as, and appear to be conspecific with the present species, although larvae have a slightly shorter trunk (0.5mm long) than the newly recorded Australian ones. Didemnum astrum sp. nov. (Figs 71, 167F; Pl. 7E) TYPE LOCALITY. Queensland (Wistari Reef, south side, low tide rubble fauna, coll. P. Kott 11.3.93, holotype QM G308015; Heron I, eastern end, lowtide rubble fauna, coll. P. Kott 4.9.94, paratype QM G308204). FURTHER RECORDS. Western Australia (off Cape Preston, WAM 1.95). Queensland (Heron I. east, QM G300912, G308112, G308130, G308136, G308142, G308145, G308199, G308206, G308245, G308477; Swain Reefs, QM G305409, G308362). Indian Ocean (Cocos Keeling, WAM 605.89). COLONY. Colonies are thin, hard but not brittle, small circular plates or sheets to more fleshy, robust encrusting sheets with rounded margins. The stellate branchial apertures usually (but not always) have spicules outlining them. Yellow or orange-yellow pigment cells are mixed with spicules and bladder cells in the superficial Jayer of the test. Zooids are scarlet* or coral-red®, and can be seen through the surface of the colony. One specimen (QM G308130) is reported to have been an even orpiment orange“ with orange zooids and another (QM G308362) was orange chrome“ with orange zooids. Only one colony i is said to have been flame scarlet" with ferruginous* zooids obscured by the spicules in the ‘surface layer. Preserved colonies usually are pale apricot, fading to white with a trace of yellow in the surface and/or basal test. The preservative often is a clear lemon colour. Spicules are crowded beneath a surface bladder cell layer and around the zooids and sometimes are only moderately crowded to relatively sparse in the basal half of the colony. Most spicules (to 0.06mm diameter) have 11—13 pointed conical rays in optical section. Some smaller ones have short rounded or flat-tipped rays or are globular, and occasionally have longer almost fusiform rays. Bases of the spicule rays usually are crowded together. The cloacal cavity is thoracic, with the colony firm and robust as a result. However, deeper primary canals are present around clumps of zooids resulting in slightly protuberant oval surface swellings surrounded by narrow depressions over the deep primary cloacal canals. When contracted, margins of the common cloacal apertures often are frilled and translucent, but when open the rims are white with crowded spicules and lack pigment. One colony (QM G308477) has large protuberant lips around the common cloacal apertures. ZOOIDS. Zooids are small, about 0.7mm long when contracted. The branchial siphon is well-formed and cup shaped, with 6 sharply FIG. 71. Didemnum astrum sp. nov. (A, QM G308204; B,C, QM G308245) — A, thorax; B, gonads and gut loop; C, larva. Scales: 0.1mm. pointed lobes around the rim of the lobes. An atrial lip was not detected. The branchial sac has 8 stigmata in the anterior rows and about 6 in the posterior row. The long, strong retractor muscle is free from about halfway down the long oesophagus. The testis has 10 coils of the vas deferens around its outer half. MEMOIRS OF THE QUEENSLAND MUSEUM Larvae are in colonies collected in March (QM G308112) and October (QM G308245) . The small trunk (0.35mm long) has 4 large lateral ampullae along each side of the 3 antero-median adhesive organs. REMARKS. The species is distinguished by the crowded, regular, pointed, conical rays of the majority ofits spicules. The long, robust retractor muscle from halfway down a relatively long oesophageal neck is also a characteristic of this species. Spicules resemble, but are smaller and have fewer and longer rays than in D. chartaceum. D. lacertosum has only slightly smaller but less diverse spicules with more rays. The spicules are similar to D. muiltispirale, although in the latter species the rays are shorter and separated from one another on the central spicule mass rather than having their bases crowded together. Spicules of D, moseleyi show the same diversity as those of the present species, but they have fewer rays. D, mutabile, D. paa and D. pitipiri from French Polynesia (Monniot & Monniot, 1987) have spicules with equally numerous, but invariably shorter rays separated from one another on the spherical central mass as in D. multispirale. The small rose-coloured specimens of D. ligulum: Monniot & Monniot, 1987 from French Polynesia have similar characters to the present species, viz. small circular colonies, and some spicules with numerous pointed rays while others have round-tipped rays (see Monniot & Monniot, 1987: pl. 2C). However, their larvae are different —a blastozooid was not detected, and they have only 4 pairs of ectodermal ampullae — and the cloacal systems are different. Didemnum bicolor sp. nov. (Figs 72, 168G; Pl. 7F,H) TYPE LOCALITY. South Australia (Investigator Group, Top Gallant I. in caves, coll. N. Holmes 10.4.83, holotype QM GH2410; Ward I, in caves, 8m, coll. N. Holmes 14.4.83, paratype QM GH2409. COLONY. Colonies are hard, irregular, encrusting sheets to 5mm thick, with black pigment in the surface contrasting with white pigment-free areas, creating a black and white marbled pattern in the surface, like a piebald horse. The pattern varies, sometimes white predominates but other parts of the surface and other colonies are almost entirely black with white only around the common cloacal apertures. Some elongate or oval areas of test are zooid free, and project slightly from the surface and zooids THE AUSTRALIAN ASCIDIACEA 4 are partially embedded along each side of the deep primary common cloacal canals that surround these areas. These primary canals are almost the full depth of the colony, and the test over them is slightly depressed in preserved colonies. However, zooids are not always confined to the primary canals, and in some places occur in clumps with shallow secondary common cloacal spaces penetrating amongst them at thorax level. Zooids open in both pigmented and unpigmented areas, their arrangement not being associated with the colour pattern. The colour pattern is present in preserved as well as in living specimens. Spicules are present throughout, although they are most crowded in the hard opaque lower half of the colony. They are small, to 0.03mm diameter. Generally they have 11—13 conical pointed or truncated flat-tipped rays in optical transverse section, but occasionally there are spicules with fewer rays (9) or more (15) and one larger spicule (0.04mm diameter) was detected. ZOOIDS. Zooids are relatively large, to about 3mm long. The thorax is almost rectangular, with a conspicuous tulip-shaped branchial siphon, a wide open atrial aperture exposing most of the branchial sac, and a bifid atrial lip from the anterior rim of the opening. This atrial lip is of variable size but usually is narrow. The branchial siphon is difficult to remove from the test, having a plug of tightly packed spicules in its test lining. A long tapering retractor projects from about halfway down the oesophageal neck, and a large lateral organ is on each side of the thorax. Eight stigmata are in the anterior row, and only in the last (fourth) row is the number reduced to 6. The abdomen is relatively short and the gut loop gently curved. Gonads are not developed in either holotype or paratype. Some zooids have small thoracic buds in the oesophageal region. REMARKS. Spicules with pointed and truncated rays, large thorax and conspicuous black and white colour pattern characterise the species. The thoraces with their large tulip-shaped branchial siphons, wide open atrial apertures and narrow atrial lips are like those of D. ossium. The latter species also has blunt-tipped spicule rays as well as those with pointed rays, but the rays are longer with sharper points than those of the present species, the spicule diameter is greater and the common cloacal systems are different from the present temperate species. D. jucundum also has a black colony but its spicules are much larger and have more numerous rays. Species FIG, 72. Didemnum bicolor sp. nov. (QM GH2410) — A, thorax; B, gut loop. Scales: 0.1mm. with a similar mixture of conical pointed and flat-tipped truncated rays are D. inveteratum which has more numerous spicule rays and larger spicules; and D. apuroto Monniot & Monniot, 1987 from French Polynesia and D. diffundum Monniot, 1995 from New Caledonia, which have spicules with fewer rays (7 to 9 and 9 to 11, respectively) than the present species and different colonies. Similar spicules occur in Polysyncraton millepore. L134 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 73. Didemum bisectatum sp, noy. (QM G302599)— A, thorax; B, gut loop, testis and coiled vas deferens; C, larva. Scales: 0.1mm, Didemnum bisectatum sp, nov. (Figs 73, 168F) TYPE LOCALITY, Northern Territory (Flat Top Bank, Timor Sea 12°16°S, 129°15°E, coll. J.N.A. Hooper, holotype QM G302599), COLONY. The hard, encrusting colony, about 3mm thick, has spicules crowded throughout. Some brownish pigment is mixed in the surface layer of test, but bladder cells were not detected. The common cloacal cavity is a shallow horizontal space at thorax level. Some plant cells are embedded in the surface test, and the preservative is stained greenish yellow, The spicules are relatively large to 0.07mm in diameter and most have 17-19 conical or flat-tipped truncated rays in optical transverse section. A few of the spicules are globular, ZOOIDS. Zooids are robust with short funnel-shaped branchial siphons with 6 pointed branchial lobes. The atrial aperture is wide, exposing most of the branchial sac directly to the cloacal cavity. A delicate narrow atrial lip (usually with a rounded tip but sometimes forked) projects from the mid-dorsal body wall just anterior to the atrial aperture. The thorax is turnip-shaped, the posterior (post-stigmatal) part gradually tapering to the part of the oesophageal neck where the strong, tapering retractor muscle THE AUSTRALIAN ASCIDIACEA 4 155 projects into the test. The top of the oesophagus is wide — almost the same diameter as the posterior end of the thorax. The lateral organ is a shallow, long, narrow concavity stretched out between the middle of the first and third rows of stigmata in the antero-lateral part of the rim of the widely stretched atrial opening. Pointed, columnar epithelial cells project from the body wall especially conspicuous along the dorsal wall of the concavity of the lateral organ. Unusual columnar cells along dorsal wall of the concavity have a papillate appearance. The concavity tapers anteriorly. Nine long narrow stigmata are in the first and second rows of stigmata, reducing to 8 in the third and 7 in the posterior row. The gut loop is short and simple and the conical to lens-shaped testis, divided into 2 lobes, with 7 tight coils of the vas deferens around it, lies against the dorsum of the pole of the gut loop. Larvae, with a trunk to 0.75mm long and the tail wound about three-quarters of the way around it are in the holotype. They have 4 subdividing ectodermal ampullae along each side of the 3 antero-median adhesive organs. Blastozooids are not present. REMARKS. Other species of Didemnum known to have 2 testis lobes are D. bimasculum Monniot, 1995 from New Caledonia which also has similar larvae, long lateral organs and the same number of vas deferens coils, but has larger spicules with fewer rays; D. uturoa has unusual bilaterally symmetrical spicules; D.recurvatum Sluiter, 1909 with globular spicules lacks an atrial tongue; an undescribed species from SW Australia that Kott (1962) erroneously assigned to D. augusti (see D. patulum below) with spicules about 0.04mm diameter, about 10 pointed rays in optical transverse section and 6 coils of the vas deferens; and D. candidum: Tokioka, 1967 from Kiribati. D. mutabile has spicules of similar size but spicules with short truncated rays are not known, the testis is undivided and the larval trunk is only 0.3mm long, with 5 ectodermal ampullae per side. D. grande: Kott, 1962 from Rottnest I. (which was said to have 2-lobed testis) appears to be an immature colony of Polysyncraton sp. (see P. palliolum, Remarks). Didemnum caesium Sluiter, 1909 (Figs 74, 170A) Didemnum caesium Sluiter, 1909: 53. Didemnum reticulatum Sluiter, 1909: 60 (part , specimens from statn 315 and statn 322). Didenmum megasterix Monniot, 1995: 315 (part, specimens from the north). NEW RECORDS. Western Australia (Montebello Is, WAM 960.93; off Port Hedland, WAM 513.92). Queensland (Capricorn Group, QM G300894, G301584, G302968, G308014, G308084-5, G308265, G308285, G308290, G308296). PREVIOUSLY RECORDED. Indonesia (holotype ZMA TU434 Sluiter, 1909; D. reticulatum ZMA TU475.6, TU475.8 Sluiter, 1909). New Caledonia (Monniot, 1995). COLONY. Colonies sometimes are thin but others are robust sheets to 5mm thick, more or less flat on the upper surface which is interrupted by large, cloacal apertures evenly spaced along elevated surface ridges. The superficial layer of test has black and brown pigment in narrow irregularly shaped cells mixed with white calcareous spicules over a layer of crowded spicules about 3 or 4 deep. A thin layer of spicules is on the base of the colony. Spicules are sparse in the remainder of the colony. Pigment cells are present in the test beneath the crowded layer of spicules, above the cloacal cavities. Cloacal spaces are oesophageal and sometimes posterior abdominal. Zooids lie more or less horizontally above the cloacal spaces with the ventral part of the thorax embedded in the surface test. Spicules often are absent around the branchial apertures, although some small groups of 2 or 3 are in the lining of some of the branchial siphons. Spicules are generally large (to 0.1mm in diameter), stellate, with 9-11 and occasionally 7 conical rays in optical transverse section with acutely pointed and sometimes chisel-shaped tips. Larger spicules predominate, but also there are some very much smaller ones in the 0.01—0.02mm diameter size range, some of which have club- shaped rays. Ray length/spicule diameter ratio is about 0).25—-0.3. In life, colonies are blue-black, or slate blue, or purple with black, with white patches around the cloacal apertures where pigment cells are absent from the test, exposing the white spicules. However, spicules are not present in the actual rims of the cloacal apertures. In preservative the colonies are purplish-brown or grey, with pale to white margins around the cloacal apertures, although the black pigment of the basal test is seen through the openings. Prochloron is present in patches on the surface of some of the colonies. ZOOIDS. Zooids are robust, reaching about 2.0mm long when relaxed. They are blackish in preservative, with black pigment in the body wall although they fade to brown in longer term preservation. The thorax is relatively broad and there is a fine, tapering retractor muscle from about halfway down the oesophageal neck. Six 156 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 74. Didemnum caesium (A,B, QM G302968; C, QM G308084; D,E, QM G308290) — A, thorax; B, abdomen; C, abdomen; larvae, D, from the right side, with tail beginning its withdrawal, and E, from above with tail being resorbed. Scales: 0.1mm. narrow, pointed lobes surround the branchial aperture, which is on a short, wide cylindrical siphon. The large atrial aperture, which sometimes exposes the whole dorsal part of the branchial sac, has a strong, muscular, bifid atrial tongue, which is embedded in the test above the cloacal cavity and sometimes is torn off when the zooids are removed. A circular lateral organ is an each side of the endostyle between the first and second rows of stigmata. There are 10 stigmata in the anterior rows of the branchial sac, 9 in the third and 8 in the last row. The gut is thick and the post-pyloric part of the gut loop is bent ventrally up against the anterior part. The duodenum is relatively long, the posterior stomach short, the proximal part of the rectum very thick and wide and the distal part relatively narrow. Sometimes a large, oval testis projects from the dorsal surface against the distal end of the gut loop. It has 6 coils of the vas deferens around its long axis, the proximal coil (from the outer tip of the oval) and the distal coil (against the gut loop itself) of smaller diameter than the coils around the middle (wider) part of the testis. However, in other specimens the testis is the usual conical shape. A large egg is dorsal or anterior to the male follicle, Embryos are being incubated in the basal test of colonies collected in March (QM G308084-5), September (QM G308290) and October THE AUSTRALIAN ASCIDIACEA 4 (G308296). In one larva only 2 adhesive organs were found — although that could be abnormal, as 3 are in the embryos being incubated in the basal test of other specimens. The larval trunk is 0.65mm long and a long tail almost completely encircles it. On each side, 4 lateral ampullae subdivide to form the 16 that encircle the anterior end of the trunk in mature larvae. The trunk is thick, without any appreciable waist. Masses of yolk are present but a blastozooid was not detected. Generally adult organs are not well advanced in the known larvae and although the pharynx is perforated in some in which the tail is being resorbed, specimens with the tail entire and epidermal ampullae well developed do not always have a perforated pharynx. Conspicuous small, oval clusters (about 0.01mm longest dimension) of minute spheres (0.002 diameter), which appear as dark dots at lower magnification, are embedded in the larval test around the base of the tail at the posterior end of the trunk of the more advanced larvae (QM G308290). The size of this mass of dark test inclusions increases as the larva matures, and although it is in the same position as the larval rastrum in Diplosoma symbioses (see D. simile, below) it is not a rastrum, the inclusions are not recognisable as symbionts and they may be test cells. REMARKS. The species is distinguished by absence of spicules from the middle of the colony, large spicules with acutely pointed rays, darkly pigmented colonies, robust zooids with wide thoraces, distinct atrial tongues, short and wide branchial siphons, conspicuously pointed branchial lobes, anterior lateral organs, oval testis and an unusual larval trunk with numerous ectodermal ampullae but no blastozooid. The colony resembles D. chartaceum in the distribution of spicules, but the spicules are a different shape. D. cuspidatum Sluiter, 1909 has colonies that are said to have been grey-blue but re-examination of its syntypes (ZMA TU440.1, TU440.2) has shown that although the spicules are similar in size and form to those of the present species, the specimens belong to Leptoclinides. The unusual oval testis follicle projecting from the dorsal surface of the abdomen, occurs in D. granulatum and D. fragile and may be an artefact. D. multispirale has similar larvae with numerous ectodermal ampullae and without blastozooids, but it lacks dark inclusions in the larvae and in the adult colony, and the spicules are different and crowded throughout. D. grande has similar spicules although they are crowded throughout and their ray length/spicule diameter is greater. Ithas a distinct spicule-free pigmented bladder cell layer, zooids arranged in clumps surrounded by deep common cloacal canals marked by depressions in the surface, and only 4 pairs of larval lateral ampullae. D. nocturnum Monniot, F. & Monniot, C., 1997 from Tanzania has a similar colony and zooids to the present species. The spicules, though of the same form, are smaller and the larvae are longer and have a blastozooid. Monniot (1995) has 2 different sorts of larvae in specimens assigned to D. megasterix Monniot, 1995 from New Caledonia, viz. specimens from the north which do not discolour in formalin have smaller larvae identical with the present species; and others from the south which do discolour in formalin have larvae about twice the size with more numerous ectodermal ampullae, blasto- zooids, and perforated oozooid and blastozooid pharynges. Larvae do not usually appreciably increase their size with development, and rather than being 2 different stages of development these larvae are from different species, the northern one the present species. Larvae of the southern forms are of the Polysyncraton type with a larval blastozooid and numerous lateral ampullae. They occur also in D. arancium, D. chartaceum, D. jedanense, D. levitas and D. precocinum, none of which have spicules like those of D. megasterix Monniot, 1995 (part, specimens from the south) which does not appear to occur in Australia. Didemnum candidum Savigny, 1816 (Figs 75,171B,C; Pl. 8A,B) Didemnum candidum Savigny, 1816: 194. Hartmeyer, 1915: 419. Michaelsen, 1919: 18 (part, specimens from Gulf of Suez): 1920: 19. Hastings, 1931: 94 (part, dredged specimens). Tokioka, 1967: 62 (part, not burr-shaped spicules). Eldredge, 1967: 213. Lafargue, 1974: 341 (part, fig. C), Kott, 1998: 81 (part, Indo-West Pacific tropical records only). Not Didemnum candidum: Van Name, 1921: 323; 1930: 435: 1945; 83. Carlisle, 1954; 314, Tokioka, 1954: 246, Kott, 1962: 328; 1972a: 19; 1972b: 179; 1975: 9; 1976: 65. Millar, 1982: 49, Leptoclinum cretaceum Sluiter, 1898: 36. Didemnum yolky Monniot, C. & Monniot, F., 1997: 1627. Monniot, F. & Monniot, C., 1997: 10. NEW RECORDS. Western Australia (Ashmore Reef Timor Sea, WAM 517.92; Kimberley, WAM 746.91). Queensland (Capricorn Group, QM G302995, G308002, G308029, G308040, G308045, G308047-8, G308111, G308113, G308125, G308129, G308183, G308186-7, G308189, G308202, G308215, G308222, G308225, G308248, G3308319, G308335; Swain Reefs, QM G305557, G305700-2, G308370, G308391, G308410, G308430, G308438). PREVIOUSLY RECORDED. Queensland (Hastings, 1931). Western Pacific (Tokioka, 1967). Gulf of Suez (Savigny, 1816; Hartmeyer, 1915; Michaelsen, 1919, 1920). Gulf of Arabia (Monniot, C. & Monniot, F., 1997). West Indian Ocean (Mozambique — Sluiter, 1898; Mauritius, Malagasy — Michaelsen, 1920; Tanzania — Monniot, F. & Monniot, C., 1997). G308399, COLONY. Colonies are thin, irregular investing sheets Generally the surface is smooth but sometimes small spicule-filled papillae ornament it (QM G308189, G308319, WAM 74.91). Minute crowded papillae on the surface of the latter specimen sometimes join up with one another to form a sort of scaffolding on the surface, including a radial pattern around the stellate branchial apertures. Specimens are found on hard substrates or weed. They always are white in preservative, but in life they are either vinaceous", vinaceous red" to flesh colour’, vinaceous rufus® , ferruginous* , brick red, flame scarlet®, dragons-blood red", vermilion", orange vermilion®, orange (saturn red") or orpiment orange" and one specimen was rose pink®. The pigment is in minute spherical cells in the superficial layer of test over the white spicules which are crowded throughout the remainder of the test. Zooids usually are darker than the surface of the colony, and are scarlet", flame scarlet", crimson", claret brown", burnt carmine*, vermilion®, or bright orange (saturn red®), They can be seen through the surface of the colony, and sometimes appear as red or orange spots with a white dot in the centre where spicules in the lining of the branchial siphon line the stellate apertures or are crowded in the test around them. Occasionally spicules appear to form a plug in the branchial siphon. Common cloacal apertures appear white inside owing to the spicules crowded in the test, although the rim of the opening is red or orange in living specimen owing to the absence of spicules there. Preserved specimens are pale apricot at first with pale transparent beige zooids. However, soon they fade to white. Extensive horizontal common cloacal spaces at thorax level have the thoraces crossing the space independently, each with a ventral test sheath that connects the surface to the basal test. The cloacal cavity sometimes extends deeper around groups of zooids, leaving clumps of abdomina projecting into the common cloacal cavity. Spicules are of moderate size, with 7-9 rays in optical transverse section never exceeding MEMOIRS OF THE QUEENSLAND MUSEUM 0.06mm in diameter, and usually being less than 0.05mm. Most have moderately long slightly club-shaped or cylindrical rod-like rays, rounded at the tip. A few have conical rays. Ray length/spicule diameter ratio is about 0.38. Spicules have a particularly large size range, many very small spicules being crowded in between larger ones. Spicules are not always evenly distributed in the surface layer of test, sometimes being crowded into clumps forming particularly opaque patches on the surface. Sometimes the surface of the colony has a sightly frothy appearance owing to the uneven distribution of spicules. ZOOIDS. Zooids are small, about !mm long. The relaxed thorax is about 0.5mm long. They have 6 well-formed, pointed branchial lobes. A wide open atrial aperture exposes a large part of the branchial sac directly to the cloacal cavity and a large thoracic organ is along the posterior part of the ventral rim of the aperture on each side. A retractor muscle of variable length is free from the middle part of the oesophageal neck. In the branchial sac are 6 stigmata in the first 2 rows, 5 in the third row and 4 in the last. Often thoraces are too contracted for stigmata to be counted accurately. Generally the thorax tapers slightly toward the posterior end. The stigmata are fusiform coming to a point at each end with 3 large, darkly staining, non-ciliated terminal cells at each end. The gut loop is relatively long, and its distal tip is flexed ventrally. In sexually mature zooids a large testis is beneath this flexed part of the gut loop. The testis is hemispherical or a low dome. The inner side, or base of the testis (the part against the gut loop) is flattened. The vas deferens always spirals 7 times around the outer surface of the testis. Larvae are present in newly recorded colonies taken in March (QM G308002, G308047-8, G308189) and September (QM G308202, G308410). Sometime they are found in the surface test, in the process of being liberated from the surface of the colony. The larval trunk is 0.3 (QM G308189, G308410) to 0.75mm long, with the usual ocellus and otolith, and 4 pairs of lateral ampullae along each side of the 3 antero-median adhesive organs. The tail is wound only about halfway around the trunk. REMARKS. This species (the type of the genus) is one of the most commonly encountered Didemnum species in Australian waters. Its thin, brittle colonies, small spicules, small zooids and THE AUSTRALIAN ASCIDIACEA 4 variable colour (some shade of red or orange) are common in the genus. In the field it can readily be confused with D. membranaceum, D. fragile, as well as many other species. Its larvae also are similar to many other Didemnum spp. The form of the spicules is the only unique character so far determined. Spicules with long pointed rays and giant spicules (as in D. membranaceum) do not occur. The spicule rays of D. perplexum are fewer, shorter and more conical than the present species, which has rod-like rays similar to those of D. fuscum but smaller. D. fuscum is further distinguished by its more numerous vas deferens coils, large dark spherical cells around the zooids and small larvae with more lateral ampullae. The only other character which helps to distinguish D. candidum from many others is the origin of the retractor muscle from halfway down the oesophageal neck, although that is by no means unique and is often obscured when zooids are contracted. Fusiform stigmata with pointed ends occur also in D, perplexum, D. sphaericum Tokioka, 1967 has similar spicules, but their rays are fewer, shorter and more conical, Specimens assigned to D. sphaericum from Fiji (Kott, 1981) have rays sometimes set in pentagonal bases. Unfortunately the type specimen of D. candidum, from the Gulf of Suez, has not survived. Hartmeyer (1915) studied a number of specimens from the Gulf of Suez in the collection of the Berlin and Hamburg Museums that he considered to be conspecific with Savigny’s species, and described them in some detail. He records encrusting, moderately thin, brittle sheets that are seldom more than Imm thick, as well as cushions and more complex colonies folded back on themselves to form semi-enclosed spaces. He found the upper surface to be smooth, pierced by 6-lobed stellate branchial apertures. The spicules, crowded throughout, are of very constant form — stellate with 7-9 regular conical rays in optical section and up to 0.06mm in diameter. The rays are slightly blunt-tipped, although smaller spicules have more pointed rays. Zooids are scarcely Imm long, with 8 stigmata per row in the branchial sac, and 5—6 coils of the vas deferens (Hartmeyer, 1915). He pointed out that the species was then known for certain only from the Gulf of Suez. Carlisle (1954) found that specimens from the Gulf of Suez identified by Hartmeyer (preserved in The Laboratory, Plymouth) were characterised by having only 2 larval adhesive organs. 159 FIG. 75. Didemnum candidum (A, QM G308186; B, QM G308189; C, QM G308202) — A, thorax; B, abdomen; C, larva. Scales: 0.1mm, However Lafargue (1972, 1974) found that all of the specimens she collected from the Red Sea had 3 (rather than 2) larval adhesive organs. It appears that Carlisle (1954), working with a mixture of species, confused European and Indo-Pacific specimens. Lafargue (1972, 1974) concluded that D. candidum Savigny, 1816 has an Indo-West Pacific range, and that it has 3 adhesive organs. Specimens assigned to the species from NW Europe, the Mediterranean and the northern Atlantic have only 2 adhesive organs and belong to D. maculosum (Milne Edwards, 1841). Lafargue (1974) erected a neotype series from Eilat in the Gulf of Aquaba (near the type location, the Gulf of Suez). Unfortunately the spicules from this syntype series are unusually diverse and it is unlikely that they are from a 160 single species. Those illustrated in figure 2C (Lafargue, 1974) are similar to the spicules in the specimens referred to D, candidum in the present work, and to those described by Hartmeyer (1915). Lafargue’s description of the zooids and colony otherwise conforms with Hartmeyer’s (1915), except in regard to the number of stigmata per row, which Hartmeyer recorded as 8 —arelatively high number. D. yolky Monniot, C. & Monniot, F., 1997 from the Arabian Gulf, conforms in every way with D. candidum. Synonymy of Leptoclinum tenue Herdman, 1886 (from the Magellanic region and the northern Atlantic) with the present species cannot be sustained, there being significant differences in spicule size and form (Michaelsen, 1919). Similarly there are significant, even dramatic differences in size, form and distribution of spicules of specimens from the tropical Atlantic proposed as synonyms by Van Name (1945). Differences of this magnitude cannot be considered intraspecific. Owing to Van Name’s authority and usual reliability in this field, the proposition (that they are intraspecific) has obscured the taxonomic significance of certain characters and distorted the definition and affinities of this and other species in Didemnum, resulting in the assignation to this species of a bewildering number of specimens from a range of locations. Specimens incorrectly assigned to D, candidum include many from temperate Australian waters with small, many rayed and sometimes globular spicules (Kott, 1972a, 1972b, 1975, 1976); and others from its known range in the Indo-West Pacific, which have different spicules (Hastings, 1931; Tokioka, 1954, 1955, 1967). Tokioka (1967: 64) included, in the present species, specimens with 1-3 testis follicles, 4 or 5 to 8 or 9 coils of the vas deferens, maximum sized spicules 0.03—0.064mm diameter, either crowded or sparse throughout or sparse above individual zooids, with 6 —9 or more (up to 15) rays in optical transverse section. He concluded that ‘The general structure of the zooids conforms well in detail with that of common didemnids’. This attempt at rationalisation reflects the confusion that has existed in this species and many others in the genus Didemnum. Didemnum chartaceum Sluiter, 1909 (Figs 76, 166G; Pl. 7G) Didemnum chartaceum Sluiter, 1909: 57, Hastings, 1931: 97, Kott, 1981: 163; 1998: 81. MEMOIRS OF THE QUEENSLAND MUSEUM Didemnum obscurum: Monniot, 1995: 319 (part: colonies from the barrier reef; ? colonies from the Seychelles). Monniot, C. & Monniot, F., 1997 p. 1626. Not Didemnum obscurum Monniot, 1969: 453. Didemnum nigrum Monniot & Monniot, 1996: 158. NEW RECORDS. Queensland (Capricorn Group, QM G302966, G308005, G308007, G308054-6, G308067-9, G308073-5, G308267-9, G308299; Swain Reets, QM G305618, G305682, G308266, G308383, G308397; Lihou Reef, QM G306993). Andaman Sea (Similan Is, QM G300950), PREVIOUSLY RECORDED. Queensland (Low Is — BMNH 1930.12.17.45 Hastings, 1931). Indonesia (ZMA TU437 Sluiter, 1909). Philippines (Monniot & Monniot, 1996). Fiji (Kott, 1981). New Caledonia (Monniot, 1995). ?Seychelles (Monniot, 1995). Arabian Gulf (Monniot, C. & Monniot, F., 1997). The newly recorded specimen QM G306993 is reported to have been from a large population on a hard, consolidated substrate on a high energy slope site on the seaward side of Lihou Reef. COLONY. Colonies are dark fleshy, encrusting sheets with a single layer of spicules beneath a thick superficial layer of bladder cells. The common cloacal cavity is a horizontal space at the level of the thoraces. Zooids are embedded in the test with the ventrum against the spicule layer and the dorsum facing the cloacal cavity. Only occasional spicules are in the basal test beneath the cloacal cavity, although a thin layer is on the base on the colony. Bladder cells throughout the test give it a spongy consistency. Branchial apertures have spicules crowded in their linings, sometimes appearing to outline the stellate opening, but sometimes crowded in the test around the aperture. In life, the colonies are ba colour’, claret-brown*, heliotrope purple", mottled brown and mauve*, dahlia purple®, magenta” or black, depending on the concentrations of pigment in the surface. In one colony there is a light grey and dark grey reticular pattern in the surface caused by clumps of spicules mixed with pigment and bladder cells in the superficial test. The newly recorded colony from the Andaman Sea (QM G300950) is black. Occasionally Prochloron is on the surface test. Burnt carmine™ to purplish-brown zooids are seen through the white spicule layer. Common cloacal apertures (about 5mm apart) have dark rims resulting from the absence of spicules, although 5 groups of spicules around the rim are continuous with the radial ribs in the roof of the cloacal cavity around the aperture. The basal test is a translucent plum colour. In preservative, colonies are purple-grey to brown, with dark purplish-brown zooids. The preservative stains brownish purple to yellowish-brown and the THE AUSTRALIAN ASCIDIACEA 4 161 label stains brown. The colour of the colony derives from the dark colour of the zooids. The test is translucent. Spicules are generally to 0.075mm diameter, rarely to 0.09mm. They are of two main types, some stellate with very numerous, short conical pointed rays (to about 30 in optical transverse section), and some almost globular with crowded flat-tipped cylindrical rays. ZOOIDS. Zooids are small, with the thorax larger than the abdomen. A forked atrial tongue projects from the upper rim of the large atrial aperture which exposes the whole dorsum of the branchial sac directly to the common cloacal cavity. A fine retractor muscle, varying in length according to its state of contraction projects from the postero-ventral corner of the thorax. Nine to 10 stigmata per row are in the branchial sac. The gut forms a rounded almost circular loop, with the proximal part of the ascending limb curved up over the gonads. The duodenum is relatively long and narrow, and the rounded posterior stomach is in the pole of the loop. The rectum is a ‘leg of mutton’ shape, wide at the proximal end, and has a constriction sharply separating it from the narrow distal end. The testis is a wide, lens-shaped follicle with 9 coils of the vas deferens around it. Larvae are present in colonies collected from the Swain Reefs (QM G308266) in July, Heron I. (QM G302966) in October, and New Caledonia (Monniot, 1995). They are large and robust, the FIG. 76. Didemnum chartaceum (A, QM G308069; B, QM G308067; C, QM G302966) — A, thorax; B, gut and gonads; C, larva. Scales: 0.1mm. trunk 0.8mm long, brown, and with about 8 often bifid lateral ampullae along each side of the 3 antero-median adhesive organs. They are brown in the preserved specimens, their colour obscuring their structure. The available larvae are not particularly well advanced, the pharynx of the oozooid not being perforated. Nevertheless, in some newly recorded specimens (QM G302966, G308266), the endostyle of a thoracic bud can be seen in the vicinity of the oesophageal neck (see also Monniot, 1995, fig. 12F). REMARKS. Spicules are distinctive, as is their distribution in the colony, the crowded bladder cells throughout the test and the dark colour of the preserved material resulting from the dark coloured zooids. However, a variety of colours has been recorded for living colonies, viz. orpiment orange® for Fijian material (Kott, 1981), while heliotrope purple*, magenta‘, as well as brown, and dark and light grey have been recorded for the newly recorded material. Hastings (1931: 98) found that ‘the tissues of the Barrier Reef specimen are of a reddish purple colour of such persistence and intensity that unstained preparations have all the appearance of having been stained.’ She thought this to have been an artefact of its preservation with other specimens, those and the label, being the same colour. It is more probable that other material in the jar had taken up the colour of this Didemnum; and that Hastings was observing the most 162 conspicuous character of this species — its dark colour in preservative. The atrial tongue is also an unusual, but not unique, character (occurring also in D. arancium, D. caesium, and other species). The present species displays a similar range of colours to living specimens of D. fuscum and D. cuculliferum, although these have white spicules rather than dark pigment in the rims of the cloacal cavities and their spicules differ. D, multispirale differs in its large, more conspicuously stellate spicules, with fewer and longer conical rays, their bases separated from one another on the central mass. Unlike the present species, the spicules are moderately crowded throughout the colonial test as well as being particularly crowded in the surface. Further, a larval blastozooid has not been detected. When immature, without gonads, Polysyncraton multiforme, with similar spicules (although smaller with fewer rays) absent from the middle layer of the colony, could be confused with D. chartaceum. D. nigrum Monniot & Monniot, 1996 is identical with the present species in every known aspect of colony, zooid and larva. Specimens from New Caledonia assigned to D, obscurum by Monniot (1995) appear to involve 2 different species neither of which is the Atlantic D. obscurum Monniot, 1969. One of the New Caledonian specimens (from the barrier reef ) which forms soft lobed colonies with character- istic larvae and spicules (to 0.06mm diameter) appears to be D, chartaceum. Larger sheets from the lagoon have spicules to 0.045mm diameter, which are rather small for the present species. D. chartaceum is readily distinguished from the Atlantic D. obscurum Monniot, 1969, Although larvae are similar, the distinctive spicules of the present species are not present in D. obscurum, which has about 13 short, wide but not crowded conical rays in optical transverse section and an ‘average’ spicule diameter 0.08mm. This suggests a particularly large maximum diameter, larger than the spicules of D. chartaceum (including D. obscurum: Monniot, 1995 from the barrier reef, New Caledonia) which only rarely reach 0.075mm in diameter. The globular spicules with flat-tipped rays, the marked ventral flexure of the gut loop over the testis, the robust brown larvae and the conspicuous bladder cells that give the test its characteristic consistency are not reported for D. obscurum. MEMOIRS OF THE QUEENSLAND MUSEUM Specimens of the present species from the Arabian Gulf (Monniot, C. & Monniot, F., 1997) and probably the Seychelles (Monniot, 1995) extend its known range into the Indian Ocean. Didemnum clayum sp. nov. (Figs 77, 172H; Pl. 8C-E) Didemnum membranaceum Sluiter, 1909: 58 (part, statn37). TYPE LOCALITY. Queensland (Heron L, filter of aquarium seawater intake, coll. P. Kott 5.3.93, holotype QM G308161; Swain Reefs, Price Cay 20m, coll. S. List 26.7.95, paratype QM G308402). NEW RECORDS. Western Australia (off Buccaneer Archipelago, QM G300946, G300961, G302914; Legendre I., WAM 515.92; Jurien Bay, WAM 103.93). Queensland (Heron I., QM G308132, G308164, G308171 G308198, G308226, G308337, G308480; Swain Reefs, QM G305681). Northern Territory (Darwin, QM G300930, G302889, G308444). PREVIOUSLY RECORDED. Indonesia (ZMA TU47].2 Sluiter, 1909). The species is said to be common in Darwin Harbour on muddy and sandy substrates. COLONY. Colonies form thin, extensive sheets with a smooth upper surface to more complex colonies with narrow (to 5mm) vertical cylindrical lobes or flattened stalks rising from the surface and sometimes anastomosing with one another (QM G300946, G300961, G302889, G302914, G308444), occasionally forming a rather open basket-work. The living holotype was blotchy pink and white to the naked eye, and other colonies are geranium pink*, peach blossom", flesh colour" and white mottled, yellow, orange and madder brown*. The orange colony (QM G308132) has a layer of spicules in the surface but few elsewhere. In all other recorded material, the test is crowded with spicules mixed with burnt carmine®, orange-vermilion* or flame scarlet’ pigment. From Darwin, one colony (QM G308444) was described by the collector as ‘red ascidian’ and another (QM G300930), said to be purple in life, appears in the in situ photograph to be reddish pink. From the NW coast specimens said to have been respectively black/grey, brown/yellow mottled and black (QM G302914, QM G300961, QM G300946) are all red in the in situ photographs. Zooids are orange- -red, orange", madder brown" or burnt carmine* and they show through the surface test with its crowded white spicules. In preservative the colonies are a dirty white colour, the zooids showing through the thin surface test as darker spots owing to the pigment cells retained in the body wall. Some colonies have minute spicule-filled papillae on some parts THE AUSTRALIAN ASCIDIACEA 4 16 FIG, 77. Didemmum elavum sp. nov. (A-C, QM G300961; D,E, QM G300946) — A, cross section through a cylindrical colony lobe showing central test core and thoracic common cloacal cavities; B, thorax; C, abdomen showing double gut loop and large egy; D, isolated testis ! surrounded by coils of vas deferens; E, larva. Scales: A, 1.0mm; B= E, 0.1mm or all of the surface and these tend to modify the colour of the colony. The cylindrical vertical stalks in certain colonies have a core of particularly crowded spicules that make a hard axis down through the centre. Sometimes (QM G308171, G308198) a conspicuous hollow papilla is associated with the ventral side of each branchial aperture and one colony (QM G308480) has 6 around each aperture as well as between the apertures. Spicules may outline the margins of the branchial apertures, but are not \ always conspicuous on the surface. Occasionally (QM G302889) some large vesicles interrupt the spicules in the surface test. The common cloacal cavity is thoracic, occasionally quite shallow, but deeper in the upright lobes of a more complex colony trom Darwin (QM G308444), Thoraces cross the cavity in independent test sheaths. Abdomina are embedded in the basal test, but occasionally (QM G308198) the common cloacal cavity extends 164 almost the whole length of a group of zooids, leaving the abdomina clumped together and projecting up into the common cloacal cavity. Common cloacal apertures are large, sessile, their margins frilled, and they occur randomly, but generally on elevated parts of the surface. Cylindrical colony lobes with a rod of central test strengthened with particularly crowded spicules, have the abdomen embedded around the outside of this axial test core. Spicules are generally 0.03—0.06mm in diameter but occasional giant spicules with 4—6 long, narrow spiky rays up to 0.1mm occur. Most spicules have particularly long, narrow rod-like rays with pointed or occasionally blunt tips. There generally are only 5—7 rays in optical section and rarely 9. Ray length/spicule diameter is in the vicinity of 0.4. Only relatively few spicules with shorter conical rays occur. ZOOIDS. Zooids are about 1mm long. The branchial siphon is short with 6 conspicuously pointed lobes around the aperture. The thorax is robust, with 9 stigmata in the anterior row, 8 in the next 2 rows and 7 in the last row. A long, tapering retractor muscle projects from the long, narrow oesophageal neck one third, to halfway down it. The ascending limb of the long gut loop is kinked up over the testis. Gonads are mature in ZMA TU471.2 (formerly a syntype of D. mem- branaceum) from Indonesia as well as in newly recorded colonies from Heron I. (QM G308171), and NW Australia (QM G300946, G300961, G302914). The testis is hemispherical, and the vas deferens spirals 8 times around its outer, domed surface, sometimes almost completely covering it — leaving only a small area toward the base exposed but with the proximal spiral wide, exposing a considerable area at the apex of the testis, Larvae are present only in specimens from NW Australia collected in August (QM G300946, G300961). They are robust, oval, the trunk 0.7mm long without a pronounced waist. Eight thick ectodermal ampullae are along each side of the 3 antero-median adhesive organs and the tail winds two-thirds of the way around the trunk. The adult organs are not well advanced, stigmata are not perforated and it is not known whether or not blastozooids develop as they usually do in other species with numerous ectodermal ampullae and a thick trunk without a waist. REMARKS. Except for the variable occurrence of surface papillae, variations in depth of the thoracic cloacal cavity and development of MEMOIRS OF THE QUEENSLAND MUSEUM upright lobes on the surface, characters of the known specimens are remarkably consistent, viz. similar gonads and branchial sacs, inconspicuous branchial apertures, unique long rod-like spicule rays and occasional giant spicules with relatively few spiky rays. Spicules differ from those of D. membranaceum and D. cuculliferum by their greater diameter, and their longer, straighter and fewer rays. The giant spicules resemble those of D. membranaceum and D. cuculliferum but occur less frequently. The vas deferens coils 8 times (as in D. cuculliferum, but only 6 times in D. membranaceum); and the branchial sac of the present species has relatively numerous stigmata. The echinated surface with minute spicule- filled papillae occur in many Didemnum spp. Also, similar pointed spines are often associated with each branchial aperture in D. cuculliferum, D. membranaceum, D. scopi and D. stragulum while the surface of the spiky colony (QM G308480) resembles Polysyncraton echinatum. Didemnum complexum sp. nov. (Figs 78, 170E) Didemnum lambitum: Kott, 1972c: 249 (part, specimen without larvae). TYPE LOCALITY. New South Wales (Port Hacking, Little Turiel Point, 60-70m on rock walls and clumps and ceilings of caves, coll. C. Lawler and URG 20.5.69, holotype AM Y820). FURTHER RECORDS, New South Wales (North Head Sydney Harbour, QM G303748). Tasmania (Triabunna, SAM E2859). COLONY. Colonies are large (to 10cm or more in greatest dimension), often complex, and usually brittle and broken into several pieces. The holotype is an encrusting base with the surface extended into crowded lobes and long branches, each with a terminal common cloacal aperture. Other colonies consist of thin sheets, over conglomerates of rubble, pebbles, shell and worn fragments, from the surface of which vertical plates and finger-like lobes protrude, anastomose with one another and create a complex fenestrated 3-dimensional mass. The basal sheet of all colonies has basal and surface layers of test separated by thoracic common cloacal cavities, the upright lobes and lamellae sometimes have a central test core, separated from the zooid-bearing layer by common cloacal spaces crossed by test connectives. Zooids open all around the outer surface of the protuberances. The surface is raspy to the touch, and in one colony (QM G303748) is covered with minute papillae between the slightly protuberant stellate THE AUSTRALIAN ASCIDIACEA 4 165 FIG. 78. Didemnum complexum sp, nov.(A, QM G303748; B.C, AM Y820) — A, colony showing common cloacal apertures; B. thorax showing long retractor muscle (folded up); C, abdomen with bent up gut loop and coiled vas deferens around undivided male follicle. Scales: A, 10mm: B.C, 0.1mm. branchial apertures. The rims of the apertures are outlined in spicules, which project in to line the siphons. Spicules are present throughout the test. They are generally to 0.06mm in diameter with 7-9 moderately long and sharply pointed conical rays im optical transverse section, Ray length/spicule diameter is about 0.4. Spicules with round-tipped rays were not detected, rays being uniformly conical and pointed. Occasional giant spicules about 0.075mm diameter with a total of 4-6 broad-based conical rays were detected. Sometimes these giant spicules are a 2- dimensional cross. 166 Zooids are in clumps, surrounded by deep primary cloacal canals with the surface test depressed over them. Thoraces are partially embedded in solid test or cross the thoracic cloacal cavity in separate test sheaths, Abdomina usually are embedded in the test connectives joining the surface to the central test core or basal test across the cloacal cavity. The living holotype specimen was described as ‘candlegrease’ ascidian and was fleshy pink and pale yellow. ZOOIDS. Zooids are small with short branchial siphons and a large sessile atrial aperture exposing the branchial sac directly to the cloacal cavity. A long fine retractor projects from the top of the oesophageal neck. Only about 6 stigmata are in the anterior row of the branchial sac. Eight coils of the vas deferens surround the lens-shaped testis. REMARKS. The spicules are similar to those of D, membranaceum, although the giant spicules of the latter species have long narrow, spiky arms. Both species have small zooids. However, D membraenaceum never has lobed 3-dimensional colonies with extensive common cloacal cavities, its zooids are slightly larger, the thoraces more comma shaped and it has 6 (rather than 8) coils of the vas deferens. D. spongioide and D. roberti have complex 3-dimensional colonies like the present one, although their colony lobes are of greater diameter and their cloacal cavities more extensive than the present species. D. roberti is further distinguished by the distribution of spicules confined to a layer in the surface and another in the base of the colony, and its tough, gelatinous colony, (rather than hard, brittle ones of D. spongioide and the present species). Spicules of D. roberti and D. spongioide also are similar to the present species although in the former the rays are longer and in the latter are shorter. Larvae referred to by Kott (1972c) are not in the holotype of the present species but in a specimen of D. lissoclinum, which Kott (1972c) also had assigned to D. lambitum. Didemnum crescente sp. nov. (Figs 79, 172F) Didemnum augusti: Kott, 1976: 68. TYPE LOCALITY. New South Wales (Eden, coll. A.R. Davis TBA5 December 1996, holotype QM G308495). FURTHER RECORDS. Tasmania (Triabunna, SAM E2854). Victoria (Western Port —MV F68801 Kott, 1976; Mallacoota Inlet — Kott, 1976) MEMOIRS OF THE QUEENSLAND MUSEUM COLONY. The holotype is a small thin sheet but the other known colonies are more extensive. Clumps of 6 or 7 zooids are in circular to longish oval area surrounded by surface depressions over deeper common cloacal canals lined on each side by zooids. These canals sometimes extend into vast posterior abdominal spaces interupted only occasionally by connectives that attach the upper zooid layer of the colony to the basal test. Shallow canals penetrate the clumps of zooids at thoracic level. The basal layer of test (beneath the zooids) is one-third of the total thickness of the colony and the thoracic and abdominal levels are a third each, Spicules are evenly spaced throughout the test, and are especially crowded in the lateral organs, which frame the posterior end of each side of the thorax in a conspicuous crescent of crowded spicules. Spicules are to 0.07mm in diameter and have 7-9 relatively long, sturdy, conical rays in optical transverse section with a ray length/ spicule diameter ratio to 0.375. The stellate branchial apertures are lined with spicules. The colony is white in preservative. ZOOIDS. Zooids are small. The branchial siphon is short with 6 relatively shallow lobes. The atrial aperture is large and sessile without an anterior tongue. The lateral organ is a large flap of the parietal body wall that lies over the crescentic mass of spicules along the edge of the test sheath at the posterior end of the thorax. A long, fine retractor muscle projects from halfway down the long oesophageal neck. The branchial sac has 7 stigmata in the anterior row. The gut forms a relatively short, rounded loop. In the holotype and the large Tasmanian specimen 9 coils of the vas deferens surround an undivided, markedly conical testis. However, neither mature gonads nor embryos are in the large colony from Western Port. Embryos are being incubated in the basal test of the holotype. The larval trunk is 0.6mm long, and 4 club-shaped ectodermal ampullae are along each side of the 3 median adhesive organs. The tail is wound two-thirds of the way around the trunk. A horizontal lateral ampulla is on the left. REMARKS. The species resembles D, patulum in some respects but the spicules have longer and fewer rays. D. incanum, the common species off the New South Wales coast, has smaller spicules than those of the present species and its cloacal systems are different, although otherwise the species are similar. The large horizontal posterior abdominal cloacal cavity, sturdy stellate spicules THE AUSTRALIAN ASCIDIACEA 4 FIG. 79. Didemnum crescente sp. nov. (QM G308495) — A, thorax with lateral organs projecting from the parietal body wall; B, abdomen with gut loop and testis with coiled vas deferens; C, larva. Scales: 0.1mm. and crescent-shaped flap-like external lateral organs are distinctive in all examined specimens . Didemnum cuculliferum (Sluiter, 1909) (Figs 80, 173C; Pl. 8F) Diplosomoides cuculliferum Sluiter, 1909: 90, Didemnum cuculliferum: Kott, 1981: 164. Not Didemnum cuculliferum: Monniot, 1995: 305 (part< D. stragulum ). Didemnum turritum Michaelsen, 1930; 521. Not Didemnum turritum: Kott, 1962: 319 (D. spongioides: Kott, 1962, part, from Oyster Bay Tasmania) has terminal cloacal openings, spicules crowded at the surface but sparse elsewhere. It is distinguished from D. fragum by its larger spicules (to 0.125mm diameter), 4 pairs of larval ectodermal ampullae (rather than 6) and a large larval trunk (to 0.9mm long), as well as the long branching stalks (3 — 7cm) that support the fleshy heads that comprise the colonies. The smaller colonies from Rottnest I. assigned to D. spongioide by Kott, 1962 (AM U3945) have been re-examined and found to be specimens of the tropical D. roberti Michaelsen, 1930 which has 18] similar, cloacal systems and spicule distribution to the present species, although its zooids are larger and more muscular, and the spicules have fewer and more attenuated pointed rays. The colony of the present species (and of D. lambitum) resembles that of Polysyncraton jugosum, but the species are separated by generic characters and by different spicules. Specimens from the east coast of Tasmania assigned to D. lambitum by Kott (1954) have similar colonies, spicules and zooids to the newly recorded material and are considered conspecific. D. lambitum (Sluiter, 1900) from New Zealand (type localities Waitangi and Chatham I.) is known from other New Zealand locations around the North and South Islands (Michaelsen 1924; Kott, 1971; Millar, 1982) and newly recorded specimens from Port Pegasus (QM G9620). Although the colony, zooids and spicule form and distribution are similar to the present species — both having a maximum of about 6 stigmata per row, a relatively restricted sessile atrial aperture with circular muscles, a tapering retractor muscle of varying length and a larval trunk about 0.9mm long — there are consistent differences between the two. Examination of the newly recorded material has demonstrated that the New Zealand species has spicules with only 9 to 11 rays in optical transverse section, a relatively short branchial siphon, longer stigmata, 10 (rather than 12) coils of the vas deferens a beehive-shaped (rather than conical) testis, and 4 (rather than 6) larval ectodermal ampullae per side. Although it has been reported that this species has separate male and female phases, both ovaries and testes are present in this colony and often in the same zooids. However, the species may be protygynous. Specimens questionably referred to D. lambitum by Millar (1982) with spicules throughout the colony, smaller larva and larger atrial aperture do not belong to this species. Nevertheless, it is not impossible that the differences detected between this temperate Australian species (with a range from Nuyts Archipelago to the central NSW coast) and the New Zealand species represent intraspecific variation. Nor can their conspecificity be ruled out on geographic grounds. Some western Pacific tropical species include North Island (New Zealand) in their range. Some temperate taxa also are recorded from around the south east of Australia and New Zealand viz.: Dumus areniferus (Ritterellidae Kott, 1992a), Euclavella 182 claviformis (Pycnoclavellidae Kott, 1990a), Botryllus stewartensis and the pachydermatina group of Pyura (Botryllidae and Pyuridae respectively and are possible Gondwanan components of the Australian-New Zealand fauna (see Kott, 1985). Didemnum fucatum Sluiter, 1909 (Figs 87, 172A; Pl. 9C,D) Didemnum fucatus Sluiter, 1909: 47. NEW RECORDS. Queensland (Heron I., QM G302980, G302996; Deloraine 1., QM GHS5753; Lizard 1., QM G302033). PREVIOUSLY RECORDED. Indonesia (holotype ZMA TU448, Sluiter, 1909). COLONY. Colonies are extensive, soft, encrusting sheets, some fleshy with rounded ridges and lobes projecting from the surface which may branch and coalesce to form a large trabecular mass in some places (QM G302980). Other colonies are fleshy slabs with a smooth surface. A conspicuous spicule-free superficial layer of bladder cells contains brown pigment. Large common cloacal apertures are spaced about lcm apart around the margin of the colony and are randomly scattered over the surface. They have spicule-free rims and are brown and conspicuous. Spicules are absent from the test over the primary common cloacal canals, which, as a consequence, appear as a brown network around whitish oval to circular areas where the white spicules in each clump of zooids show through the surface test. The circular primary common cloacal canals extend the full depth of the zooids separating them into clumps. These primary canals expand into posterior abdominal spaces, interrupted by single connectives anchoring each clump to the basal layer of the test. Thoracic cavities penetrate amongst the zooids in each clump. Zooid openings are along each side of the primary cloacal canals as well as in the centre of each clump of zooids. Spicules are fairly evenly but sparsely distributed in the middle layer of the colony beneath the thoracic common cloacal cavities and in the test in and around each clump of zooids but they are rare elsewhere. They are large, to 0.1mm in diameter with 9-11 long, pointed rays in optical transverse section. Rays vary in length. Ray length/spicule diameter ratio is up to 0.4. In life, the newly recorded specimens appear black to bottle- or olive-green or brown with the reddish to brown (ferruginous) zooids clearly seen through the greenish, translucent to MEMOIRS OF THE QUEENSLAND MUSEUM transparent test. In preservative colonies are brown and the test is translucent. In some colonies large brown spherical bodies are in some parts of the test. Eggs are reddish and translucent. ZOOIDS. Zooids are about 1.3mm long, with the abdomen small, about one-third of the length of the thorax. The branchial aperture, on a small siphon, has 6 narrow pointed or tongue-like lobes around the rim. The branchial siphon is small. The atrial aperture is a small, sessile opening, on the posterior third of the dorsal border of the thorax. It opens directly into the cloacal cavity that surrounds each group of zooids. It is a circular or occasionally transverse opening (depending on the condition of the zooid). Fine transverse muscles cross the dorsal line of the zooid anterior to the atrial aperture, fine longitudinal muscles extend down each side of the parietal thoracic wall and fibres from the most dorsal longitudinal bands join a sphincter around the atrial aperture. Posteriorly the longitudinal muscles join an annular muscle ring around the oesophageal neck of the zooid which appears to constrict the neck. Paired dorsal longitudinal pharyngeal muscles along each side of the dorsal mid-line of the pharynx are strap-like but delicate. There is no retractor muscle. A circular lateral organ is in the middle of each side of the thorax opposite the interspace between the first and second rows of stigmata. The stigmata are large and oval, 9 in the first row reducing to 7 in the last 2 rows. The short, open gut loop has the usual subdivisions (stomach, long duodenum, small round posterior stomach, and a long rectum with a constriction surrounded by tubules of the gastrointestinal gland halfway along its length). A single vascular stolon projects from the concave (ventral) side of the gut loop. Mature dome-shaped testes each surrounded by 5 coils of the vas deferens, are present in the holotype and in QM G302980. Embryos and larvae are present in the holotype. The larvae are present just below the upper surface of the colony and are very likely liberated directly through the surface test. Larvae are large, the larval trunk from the holotype being about 1.1mm long. Four long finger-like lateral ampullae are along each side of the 3 antero-median adhesive organs. A large circular lateral organ is invaginated into the parietal body wall on each side of the larval thorax. A blastozooid is not present. The oozooid is well-developed with otolith, ocellus, vertical gut and 3 rows of stigmata in the branchial sac, the tail is wound only two-thirds of the way around the trunk. THE AUSTRALIAN ASCIDIACEA 4 183 FIG. 87. Didenmunt fucarum (A,B,D, QM G302980; C, QM GH45753; E, ZMA TU448) ~ A. colony: B, zooid; C, thorax; D, gut loop and testis: E. larva. Scales: A, $.0mm; B-E, 0.1mm REMARKS. This species is an unusual member of Didemnum. \t differs from other Didemnum spp. in its posteriorly directed small, sessile atrial aperture which, although it is not as long, is possibly closer (morphologically) to the posteriorly directed atrial siphon of Leproclinides than to the large openings of Didemniwmn, which expose a great part of the branchial sae directly to the cloacal cavity. The species also resembles Leptoclinides in the absence of the retractor muscle, although the oesophageal muscle that is present does not occur in Leptoclinides, However it occurs in other Didemnidae (Diplosoma ata Monniot & Monniot. 1987 and Lissoelinum rosenm and L. nebylosum) and cannot be regarded as phylogenetically significant at genus level. The spicules also are unusual in Didemmnum, to some extent resembling those of D. psammatode and Leptoclinides caelestis. Again, this is not phylogenetically significant at genus level, although usually the spicules can be regarded as a species characteristic. The anterior position of the lateral organ, which in Leproclinides is on each side of the base of the 184 atrial siphon and in Didemnum between the third and fourth rows of stigmata, is unusual. Other characters such as zooid size and undivided testis are similar in Didemnum. Larvae are similar to those of many Didemnum spp., without blastozooids, with a simple vertical oozooid in the centre of the larval trunk and the lateral ampullae simple, finger-like, without balloon shaped tips or modified epithelrum, The large lateral organs present in the larval thorax resemble those present in the larval thorax of Atriolum robustum. Re-examination of the holotype has shown that Sluiter’s (1909) description of the colony was generally accurate, although the unique nature of the zooid (with the small, posteriorly directed, sessile, atrial aperture, and absence of a retractor muscle) and the large spicules (with relatively few, and particularly long rays of variable length) were overlooked. The atrial aperture of D. cineraceum: Monniot, 1995 is small, but is different from the restricted circular opening of the present species. Didemnum fuscum Sluiter, 1909 (Figs 88, 171A) Didemnum fuscum Sluiter, 1909; 52. Not Hypurgon fuscum Oka, 1931: 287 ( D. ligulum: Monniot & Monniot, 1987, part, orange colonies), D. chartaceum, D. jedanense and D. precocinum but all 4 species have a larval blastozooid, different spicules and other aspects of their zooids and colonies that distinguish them. The present species has a similar but smaller larval trunk than D. /igulium Monniot, 1983 from the tropical western Atlantic, and lateral ampullae are more numerous in the latter species. Further in specimens from Guadeloupe the spicules have shorter conical rays and the cloacal cavities are posterior abdominal. The flat rose-coloured colonies also assigned to D. ligulum: Monniot & Monniot, 1987 have similar but smaller larvae than the present species and similar spicules with pointed and blunt- tipped rays but the rays are longer and more THE AUSTRALIAN ASCIDIACEA 4 21 numerous. Further, these rose-coloured specimens have distinctive colonies with discrete systems isolated from one another by solid walls of test (as in Polysyncraton glaucum). They appear to be an undescribed species. D. ligulum: Monniot, 1995 from New Caledonia is a distinct species (D. ossium below) with more numerous larval ectodermal ampullae. Didemnum mutabile Monniot & Monniot, 1987 (Figs 101D,E, 167A) Didemnum mutahile Monniot & Monniot, 1987: 37, NEW RECORDS. Queensland (Heron I., QM G308205). PREVIOUSLY RECORDED. French Polynesia (Moorea, Tahiti - Monniot & Monniot, 1987). COLONY. Although the French Polynesian type material consisted of small thin orange plates, the newly recorded colony is a hard, narrow irregular strip, about 3cm long, a dirty beige colour in life and white in preservative. It lacks a spicule-free superficial layer of test, and the colony has a raspy surface. Spicules (to 0.06mm diameter) are crowded throughout. They are stellate, with 17-19 short conical, pointed rays in optical transverse section and are remarkably uniform. The bases of the spicule rays are not crowded together, and are separated from each other on the central spherical mass of the spicule. Plugs of spicules are present in the branchial siphon. The common cloacal canal is shallow and thoracic with zooids crossing it in test sheaths crowded with spicules. ZOOIDS. Zooids are relatively small when contracted, although the branchial siphon remains large and turnip-shaped, often of greater diameter than the thorax. Its shape is maintained by the clumps of spicules in the test that turns in to line the siphon. Six small sharply pointed lobes surround the rim of the branchial opening. The atrial aperture is a relatively limited sessile opening with a lip of variable length, sometimes bifid at the tip, but often inconspicuous, projecting from the anterior rim of the opening. The branchial sac has about 7 stigmata in the anterior row, although these could not be counted accurately. A conspicuous, strong, retractor muscle projects from the upper part of the oesophageal neck although in contracted zooids it appears to project from near the posterior end of the thorax. The gut forms a circular loop. The testis is surrounded by 7 coils of the vas deferens. Larvae are not in the new specimen but in the type material (Monniot & Monniot, 1987) have a trunk about 0.3mm long, with 5 pairs of in ectodermal ampullae, and the tail is wound almost the whole way around it. REMARKS, The large turnip-shaped branchial siphon, filled with a plug of spicule-filled test also occurs in D. multispirale, which also lacks a bladder cell layer, but is distinguished by the fewer rays on the stellate spicules, some globular spicules, 9 coils of the vas deferens and 10 larval ectodermal ampullae. D. /evitas also has 7 coils of the vas deferens, a similar branchial siphon, and 17-19 spicule rays in optical transverse section. It is distinguished by the absence of spicules from the middle layer of the test and by its more numerous larval ectodermal ampullae. D. ossium and D. bicolor also have large turnip-shaped branchial siphons, but they have a greater diversity of spicules including stellate ones with long, pointed rays. Although zooids of the newly recorded specimen are not smaller than those generally occurring in this genus Monniot & Monniot (1987) described the zooids of the type material as particularly small (0.6mm long), However, the zooids they figure (Monniot & Monniot, 1987, fig. 11 A-E) have very contracted thoraces, except for the branchial siphon which is the characteristic shape, probably prevented from contracting by its plug of spicules. Didemnum oblitum sp. nov. (Figs 102,165-[) TYPE LOCALITY. Queensland (Swain Reefs, Price Cay west side 20m, coll. 8. List 26.7.95, holotype QM G308380; Gannet Cay 25m, coll. S. List 24.7.95, paratype QM G308363; Thomas Cay 30m, coll. S. List 29.7.95, paratype QM G305733; Frigate Cay 20m, coll. S, List 27.7.95, paratype QM G305605; Price Cay SW side, 20m, coll, S, List 26.7.95, paratype QM G308386). FURTHER RECORDS. Queensland (Hervey Bay, QM G308472; Swain Reefs, QM G308387, G308400, G308403, G308428). COLONY. In life colonies are thin, slate- coloured, irregular sheets growing over coral rubble. White spicules are mixed with black pigment in the surface test. Black pigment seems to be concentrated around the branchial apertures. Spicules are absent around the rims of the cloacal apertures which appear black. Pigment is absent from the margins of the colony, which are cream. White spicules are crowded into the branchial siphons creating white spots on the surface, although when the apertures are open in life the chinese orange* zooids are seen. In preservative the upper surface is black, the zooids are brown and diffused yellowish-brown pigment FIG. 102. Didemnum oblitum sp. nov. (QM G308386) — A, thorax; B, gut loop and testis; D, larva. Scales: 0.1mm. is in the basal test and amongst the spicules in the outer margins of the colonies. Reservoirs of black pigment also are in the basal test. The preservative stains brownish yellow. Colonies are very soft, despite the spicules being crowded throughout. A large horizontal cloacal cavity is at thorax level with thoraces crossing it independently in their own test sheaths. The abdomina are embedded in the basal test, as are developing embryos. Spicules are globular, rarely to 0.05mm in diameter and more often less than 0.04mm. Rays are compacted or separated but always are flat-tipped. They usually are thick and not particularly numerous, about 9-11 in optical transverse section. ZOOIDS. The contracted zooids are about 1mm long. The thorax is small with only about 6 stigmata per row. A short but robust retractor projects from halfway down the short oesophageal neck. The post pyloric part of the gut MEMOIRS OF THE QUEENSLAND MUSEUM loop is bent up against proximal part. The vas deferens is coiled 8 times around the undivided testis. In preservative, brown embryos are being incubated in the basal test of the holotype colony. The larval trunk is 0.75mm long, the tail is wound about two-thirds of the way around it. Four ectodermal ampullae are along each side of the 3 antero-median adhesive organs, and an otolith and an ocellus are present. REMARKS. The colonies resemble those of Lissoclinum badium with their slate grey colour with spicules crowded in the sides and base (which are white as a result). Both species have vast cloacal cavities, and are soft and thin. However, in L. badium, the surface test has yellow pigment mixed with the black, the cloacal cavity is deeper (extending the full length of the zooid), and the colony is more rubbery. Zooids of L. badium are not chinese*- or orpiment-orange® in life as are those of the present species. The globular spicules are larger and have fewer rays than those of D. albopunctatum or D. fragile. D. brevioris Monniot, F. & Monniot, C., 1997 from Tanzania has spicules very like those of D. oblitum, and possibly the same size (although the maximum size of D. brevioris spicules is not recorded). In both species the zooids remain brown in preservative, although D. brevioris lacks the black pigment that is in the surface test of the present species, and it has a smaller larva with a blastozooid. Larvae of the present species are characteristic of Didemnum, with 4 pairs of ectodermal ampullae and they have no characters that would distinguish them from other species. Didemnum ossium sp. nov. (Figs 103, 168C; Pl. 12C;D) Didemnum (Didemnum) misakiense: Tokioka, 1967: 75 (part, specimens from the Philippines). Didemnum spongioides: Millar, 1975: 232. Didemnum ligulum: Monniot, 1995: 313. TYPE LOCALITY. Western Australia (Fenelon L., Institut Is, Bonaparte Archipelago 14°08.3S 125°41.5E, 20m dead coral, rock substrate with gorgonians and sponges, coll. AIMS Bioactivity Group 19.8.91, holotype QM G300986; Monte Bello Is 8ml NW Flag 1. 20°27.08S 115°30.09°E, sandy slope 4m, coll. AIMS Bioactivity Group 27.8.88, paratype QM G302927; Lord Mayor Shoal 20m, coll AIMS Bioactivity Group 13.8.91, paratype QM G300967). FURTHER RECORD: Northern Territory (English Company Is, QM G302908). PREVIOUSLY RECORDED. Western Pacific (New Caledonia — Monniot, 1995; Philippines — Tokioka, 1967; Millar, 1975). THE AUSTRALIAN ASCIDIACEA 4 The species is said to be rare in all newly recorded locations. COLONY. In life colonies are sessile hemi- spherical clumps of relatively fleshy yellowish cream to yellow, or orange and red, or red, club-shaped to cylindrical and often branched lobes about 3cm diameter with randomly distributed and terminal common cloacal apertures. In preservative, there are stalk like branches only about 1.5cm diameter as well as wider and flattened lamellae which look like white curved bones. A posterior abdominal common cloacal cavity separates the outer zooid layer from a core of test and is continuous with thoracic spaces that penetrate in amongst the thoraces. Spicules are particularly crowded in the very centre and form a hard rigid rod in the cylindrical lobes and 2 or 3 parallel rods extending down the central test of the lamellae. Spicules are slightly less crowded in the remainder of the test. Large elliptical openings randomly placed over the surface are from depressions harbouring commensal amphipods. The connecting strands of test between the surface zooid-bearing layer, and the central core of test are relatively few. Spicules of 2 types, stellate to 0.06mm diameter with 11-13 long, sharply pointed conical rays in optical transverse section, sometimes with bifid tips; or smaller more mulberry-like to globular spicules with short rounded or flat-tipped rays. Generally rays of the stellate spicules are not very crowded and seem isolated from one another on the central mass and often there are what appear to be stumps of broken rays amongst the others. ZOOIDS. Zooids are robust. A relatively long cylindrical or tulip-shaped branchial siphon with 6 points around the aperture is about the same length as the contracted thorax. A bifid atrial tongue of varying size protrudes from the anterior rim of the aperture. A large oval lateral organ is on each side of the thorax. Ten stigmata were detected in the anterior row of the branchial sac. A long tapering retractor muscle extends from about halfway down the oesophagus through the whole thickness of the zooid layer of the test. The post-pyloric part of the gut loop bends up to form a double loop. The testis is top-shaped, coming to a distinct point at the proximal end of the vas deferens which coils 9 times around it. Embryos and larvae are present in all newly recorded (collected in August and November) FIG. 103. Didemnum ossium sp. nov. (A, QM G302927; B,C, QM G300986) — A, thorax from dorsal surface; B, gut loop and testis; C, larva. Scales: 0.1mm, and previously recorded colonies except one from the Philippines (Tokioka, 1967). The larval trunk is 0.9mm long and the tail is wound two-thirds of the way around it. A distinctive corolla of 34 long narrow, blade-like ectodermal ampullae encircle the anterior end of the larval trunk with its 3 antero-median stalked adhesive organs. The axial cones of the adhesive organs are turnip-shaped. A slight waist separates the adhesive array at the anterior end of the trunk from the developing oozooid and blastozooids in the posterior two-thirds of the trunk. The larval pharynx has about 9 stigmata in the first row of 3, and the thoracic blastozooid (at the base of the oesophageal neck on the right side of the trunk) also has 9 stigmata per row. Halfway up the oesophageal neck on the same side Is an abdominal blastozooid. An otolith and an ocellus are in the cerebral vesicle. REMARKS. Although the colour of living specimens is variable the species always has characteristic lobed colonies, posterior ab- dominal common cloacal cavities, 2 types of spicules (one with blunt-tipped rays and others with sharply pointed and numerous rays), a conspicuous branchial siphon, small atrial lip, and an unusual larva with a corolla of numerous narrow ectodermal ampullae and blastozooids. Temperate D. /issoclinum has similar colonies, but different spicules, zooids and larvae. D. inveteratum, known only from NW Australia where it occurs within the range of the present species, has similar but larger spicules, and a thin, hard, encrusting colony without posterior abdominal cloacal cavities. Spicules of the present species are similar to, but smaller with more rays and are more crowded than in D. elongatum. Also, D. elongatum has a different colony form, longer branchial siphon and oesophageal neck, and only 6 coils of the vas deferens. The colony of the present species slightly resembles that of D. spongioide, but the lobes do not anastomose in the same way, the surface is smooth, spicules have more numerous and more acutely pointed rays, the surface layer of test over the thoracic component of the cloacal cavities is thicker, branchial siphons longer, and larvae have more ectodermal ampullae. Japanese D, misakiense (Oka & Willey, 1892), to which Tokioka (1967) had assigned Philippine colonies of the present species, has smaller spicules with fewer rays. Larvae of the Japanese species are not yet known. Species known to have a similar larva (with 30 ectodermal ampullae and blastozooids) are few, viz. D. ligulum Monniot, 1983 from Guadaloupe (with large spicules and 19 or more robust conical rays: see D. arancium, Remarks). D. linguiferum Monniot & Monniot, 1996 from Indonesia (with thoracic common cloacal cavities, not more than 6 stigmata in a row, only about 6 coils of the vas deferens, and large spicules to 0.08mm diameter with 15-17 robust conical rays), and D. guttatum Monniot & Monniot, 1996 from Indonesia (with relatively few spicule rays, rounded ectodermal ampullae and thoracic cloacal cavities). MEMOIRS OF THE QUEENSLAND MUSEUM D. ligulum: Monniot, 1995 from New Caledonia has an identical colony (Monniot et al., 1991: 179, not Monniot & Monniot, 1981 (sic) as cited in Monniot, 1995: fig. 8 caption) to the type material of the present species and to previously recorded synonyms (Tokioka, 1967; Millar, 1975). Zooids and larvae (where present) are also similar except for the usual variations in the reported numbers of stigmata and coils of the vas deferens. The rounded or flat-tipped spicules are not recorded for the synonyms listed above, maximum spicule size and diversity have not been reported. Monniot & Monniot (1996, pl. 2C) had an opportunity to examine the spicules by SEM, and illustrated only stellate spicules. These are identical with the types, as are all other characters. Further examination could demonstrate the same diversity in the spicules as in the type material . Didemnum parancium sp. nov. (Figs 104, 166E) TYPE LOCALITY. Queensland (Bowden Reef off Townsville, 190°3.1S 147°55.6E coral reef crevices, caves 10m, coll. AIMS Bioactivity Group 6.2.87, holotype QM GH5353). COLONY. The colony is a smooth, thin (about 2mm) encrusting sheet, crowded with spicules and with a rippled base. Living, it is pink/orange. Despite the crowded spicules, and possibly because they are so small, the colony is flexible. Branchial apertures are apparent from the surface as small beige dimples arranged more or less in double circles. However, neither common cloacal canals nor common cloacal apertures were detected. Although mature larvae are being incubated in the basal test and sperm are present in mature testes and vasa deferentia, the colony is in vegetative phase with thoracic buds in the oesophageal region. Zooids occupy the full depth of the colony and larvae are embedded in the base. Spicules are small (to 0.04mm diameter) globular and burr-like with numerous long rod-like rays. ZOOIDS. Thoraces are relatively long and narrow with a short branchial siphon. A short, narrow retractor muscle projects from the top of the oesophageal neck. Eight stigmata are in the 2 anterior rows, reducing to 6 in the posterior rows. The gut forms a rounded loop, curved ventrally with the testis against the postero-dorsal side of the distal part of the loop to form a rounded, almost spherical, abdomen. The vas deferens THE AUSTRALIAN ASCIDIACEA 4 21% FIG. 104. Didemmun parancium sp. nov. (QM G 5353) —A, thorax; B. gut loop and testis; C, larva. Scales: Q.1mm. makes 6 coils around the outer shallow dome-like surface of the undivided testis. Conspicuous spherical translucent cells, 0,01mm in diameter, are in the haemocoel beneath the epidermis of the zooid and are especially crowded around the gut loop, between the 2 limbs of the loop and in the major blood sinuses, The larval trunk is 0.8mm long and the tail is wound three-quarters of the way around it. Three pairs of ectodermal ampullae and 2 antero- median adhesive organs were in 3 of the 4 examined Jarvae, but the other larva had 3 adhesive organs. The spherical cells present in the haemocoel of the adult zooids are also present in the posterior end of the larval haemocoe!l behind the oozooid. A mass of yolk is present anterior to it. REMARKS. The spicules resemble those of D. fragile and D. albopunctatum, but they have a greater maximum diameter. The former species is a similar colour (pink/orange) and has a similar number of vas deferens coils, but it has 4 pairs of ectodermal ampullae and always 3 adhesive organs, The latter has only 2 adhesive organs but it has 4 pairs of ectodermal ampullae more numerous coils of the vas deferens, the colony has dark pigment in the surface and a conspicuous superficial bladder cell layer. D. pitipiri Monniot & Monniot, 1987, from French Polynesia, also has only 2 adhesive organs but 6 pairs of epidermal ampullae, and stellate spicules with conical rays. D. parau Monniot & Monniot, 1987 has similar but smaller spicules, 6 vas deferens coils, and a similar-sized larval trunk, but it has 3 adhesive organs and 4 pairs of lateral ampullae. D. parancium is characterised by its burt-like spicules, 2 or 3 adhesive organs, 3 pairs of ectodermal ampullae, 6 coils of the vas deferens and a thin colony. The large brown spherical cells in the adult and larval haemocoel occur in other species (see Glossary, haemocoel). Didemnoum patulam (Herdman, 1899) (Figs L05A,B, 169-[; P1.12E) Leptoclinum patulym Herdman, 1898: 448 (nom, nud. ): 1899: 92, Herdman & Riddell, 1913: 888, Not Didemnum patuum: Kott, 19724: 18, 1972b: 179: 1976: 635: 1998: 83 (< D. macraxiphanium). Didemniun august: Kott, 1962: 323 (part, colony from Balnarring Beach): 1998; 81 (part, Balnarring Beach only), 220 NEW RECORDS. Victoria (Gabo I., SAM E2839; Cape Woolamai, MVF70223; Western Port, QM G302899; Bass Strait, MVF70207). PREVIOUSLY RECORDED. Victoria (Balnarring Beach —Kott, 1962). New South Wales (Port Jackson —Herdman 1899). COLONY. The newly recorded colonies are thin, hard, investing sheets about 5mm thick growing around sponge or weeds. Zooids are along each side of the deep but narrow canals that surround slightly elevated, oval, opaque, paler zooid-free areas, about 2-3mm in maximum extent, that form a mosaic on the upper surface. The surface of the preserved colony is slightly depressed over the cloacal canals, and the test is slightly translucent, owing to the relatively shallow depth of spicules in the layer over the canals contrasting with the opaque zooid-free areas which extend through the whole thickness of the colony. Sessile common cloacal apertures occur randomly at junctions of the cloacal canals. Spicules are present throughout and continue without interruption down into the siphon linings. They are slightly less crowded in the lower half than in the upper part of the colony, although a crowded layer is on the base. They are stellate, to 0.07mm in diameter, with 9-11 relatively short, blunt conical rays in optical transverse section. Ray length/spicule diameter ratio is about 0.24. ZOOIDS. Zooids are not readily removed from the test, possibly owing to the crowded spicules, and were examined in stained, decalcified slices of the colony. They are particularly small, the contracted thorax being about 0.2mm long, and are covered with distinct projecting, round- tipped, columnar epidermal cells. The branchial siphon is short, with 6 narrow pointed lobes around its rim. A strong, tapering retractor muscle projects out from halfway down the long oesophageal neck. The atrial aperture is sessile, exposing a large part of the branchial sac directly to the cloacal canal. Gonads are not developed in the newly recorded zooids, nor are they described for the holotype. Kott (1962) recorded 8 coils of the vas deferens around an undivided testis in the specimens from Balnarring Beach. REMARKS. The holotype is a large colony (8cm maximum dimension). The mesh-work of grey lines is present in both the type and one of the newly recorded specimens (QM G302899), although the other (SAM E2839) has more crowded spicules than those reported by Herdman (1899) and there is no trace of pigment. MEMOIRS OF THE QUEENSLAND MUSEUM The specimen of D. augusti: Kott, 1962 was assigned on the basis of the cloacal systems. This type of cloacal system with zooids along each side of canals that surround spicule-free areas does occur in other species in this genus (e.g. D. microthoracicum, D. macrosiphonium). As Kott (1962) pointed out, D. augusti Michaelsen from the western Indian Ocean differs from the Australian specimens (which she had thought to be conspecific) in its spicules. It is clearly a different species. The specimen of D. augusti: Kott, 1962 from Balnarring Beach belongs to the present species; colonies from Reevesby I. probably are D. microthoracicum; and those from Western Australia with 2 testis follicles belong to a third (as yet undetermined) species. D. patulum: Kott, 1972a,b and 1976, respectively from South Australia and Port Phillip Bay (Victoria), with similar cloacal systems, but larger zooids, longer branchial siphons and an atrial tongue from the body wall anterior to the rim of each opening, belong to D. macrosiphonium,. D. crescente, a sympatric species, has similar cloacal systems but spicules with fewer and longer rays. Didemnum pecten sp. nov. (Figs 105C—F, 170A; PI. 12F-H ) TYPE LOCALITY. South Australia (Kangaroo I, 35°45.9 S, 137° 46.5’ E, underside of overhang 6m, strong current, coll. AIMS Bioactivity Group 1.2.89, holotype QM G300929). FURTHER RECORDS. South Australia (Point Souttar, QM GH5439). Victoria (Lorne, AM Y2319), New South Wales (Jervis Bay, QM G302898). COLONY. The holotype colony consists of double-sided fan-shaped, branching lamellae, probably standing vertically, with the upper margin and one side of the lamella produced into rounded, stumpy lobes, each with a terminal common cloacal aperture. The colony from Lorne (AM Y2319) is similar — an extensive but irregular sheet with small cylindrical elevations crowded at one end, each with a terminal common cloacal aperture. The colony from Jervis Bay is a clump of rounded upright lobes joined basally, each tapering to a terminal common cloacal aperture. The test is firm, the outer surface smooth with a thin superficial layer of bladder cells over a layer of spicules at branchial siphon level. Spicules are absent from the remainder of the colony. Thoracic common cloacal canals penetrate between the zooids which are crowded in a layer beneath the spicules. The zooid layer of the colony is THE AUSTRALIAN ASCIDIACEA 4 FIG, 105. A, B, Didemnum patulum (A, SAM E2839; B, MV F70207) — A, zooid; B, thorax. C-F, Didemnum pecten sp. nov. (C, AMY2319; D,F, QM G300929; E, QM G302898) —C, portion of colony; D, thorax; E, gut loop and testis; F, larva. Scales: A,B,D-F, 0.1mm; C, 1.0cm. separated from a central core of text by extensive posterior abdominal common cloacal spaces. The spicules are up to 0.065mm diameter, although smaller ones predominate. They are stellate, with 9-11 and occasionally only 7 conical rays in optical transverse section but the conical rays are broadly based rather than slender and are blunt-tipped. The ray length/spicule diameter ratio is about 0.36. In life the colonies are bright red-orange. They are common in otherwise predominantly sponge communities at known locations. ZOOIDS. Branchial siphons are long, almost half the length of the thorax, with 6 narrow points around the opening. Generally the thorax is roughly rectangular, with much of the branchial sac exposed directly to the common cloacal cavity by the wide open atrial aperture. Only about 6 stigmata are in each row, but these could not be counted accurately. The thorax (excluding the branchial siphon), oesophageal neck and post-oesophageal part of the gut loop are all about one-third of the length of the zooid, which is only about Imm overall. A retractor muscle projects from about halfway down the oesophageal neck. The markedly dome-shaped testes at the side of the post-pyloric part of the gut loop has 9 coils of the vas deferens around it. Larvae, present in the holotype and the colony from Lorne (AM Y 2319), collected in November, are in the central test, the larval trunk is about 0.5mm long and the tail is wound all the way around it. Five long, finger-like ectodermal ampullae are along each side of the 3 antero-median adhesive organs. REMARKS. The species resembles the tropical D. roberti which also has vertical lamellae strengthened by a firm central test core surrounded by posterior abdominal common cloacal cavities, a similar small larva (but with only 4 lateral ampullae per side) and spicules principally in a layer beneath the surface. However, D. roberti has larger spicules (to 0.09mm diameter) with attenuated rays. D. sucosum resembles the present species in colony form and cloacal systems but has larger spicules (to 0.125mm diameter) D.fragum is a sympatric species with long branchial siphons, similar but larger zooids, more vase-shaped single to 3-lobed colonies, larger spicules with more and shorter rays, more (12) coils of the vas deferens and a larger larva with more (6 per side) larval lateral ampullae. D. pellucidum also has a larger larval trunk, and more (12 per side) larval lateral ampullae and larger spicules (to 0.1mm diameter). The temperate D. spadix has similar spicules, but its thin, sheet-like colony with spicules crowded throughout, absence of a posterior abdominal cloacal cavity and free spherical brown cells in the colony distinguish it from the present species. Didemnum pellucidum sp. nov. (Figs 106, 169C; Pl. 13A—-C) TYPE LOCALITY. South Australia (Yorke Peninsula, Edithburgh jetty pile with Borrylloides leachi, 2 to 3m, coll. K.L. Gowlett Holmes 11.4.92, holotype SAM E2622). Western Australia (South of Yallingup, canal rocks off boat MEMOIRS OF THE QUEENSLAND MUSEUM ramp under limestone ledge 2m, coll. K.L. Gowlett Holmes 19.1,93, paratype SAM E2696; Rottnest L, off Parker Point, rocky reef, high energy location 9 m on wall beneath undercut, coll. AIMS Bioactivity Group, 15.3.89, paratype QM G300985). FURTHER RECORDS. South Australia (Yorke Peninsula, QM G300944; Eyre Peninsula, SAM E2651; St Vincent Gulf, SAM E2606, E2654-5; Kangaroo L, SAM E2858). COLONY. The colonies form soft, bulky, fleshy, but robust often irregular masses, with rounded margins, almost cylindrical branches, dome-like swellings (about |cm in diameter) and rounded ridges. One colony (QM G300944) is a number of vertical lamellae that branch and fuse and separate into dome-shaped lobes or ridges on the upper surface. Another (SAM E2606) is a massive hemisphere composed of vertical lobes that fuse along their length but separate out into dome-shaped prominences or ridges with terminal common cloacal apertures on the upper surface, The surface of all colonies is smooth but sometimes creased. Common cloacal apertures are terminal on the vertical lobes and around the rounded margin of the colony. Zooids are in groups in the upper part of the fleshy colonies. The common cloacal cavity is deep around each group of zooids, extending into a vast posterior abdominal cloacal cavity which is interrupted by relatively few narrow vertical connectives joining surface zooid-containing layers to the basal or central test. The cavity also penetrates each group of zooids at thorax level. On the surface of the colony, the branchial apertures sometimes are drawn down into the soft thick upper layer of test. They are conspicuous as white spots created by the plug of crowded spicules in the siphon linings. The branchial siphons are long, about half length of thorax or more (to extend through the upper layer of test), and often tear when attempts are made to remove zooids from the test. Generally, sparse, but evenly spaced spicules are in the surface of the colony and around the zooids, They are slightly more crowded over the top of the branchial siphons and down into the siphonal linings than they are between the zooids (although this could result from contraction of the zooids) and they are present in a thin layer on the base of the colony but are sparse or absent from the remainder of the test. However, in one of the paratypes (QM G300985) spicules are moderately crowded throughout the test. Spicules have a big size range, smaller ones and larger ones (occasionally to 0.1mm diameter) THE AUSTRALIAN ASCIDIACEA 4 223 FIG, 106, Didenmnim pellucidum sp. nov. (AE, SAM E2696; B, QM G300985; C.D. SAM E2622) —A, vertical section of colony; B,C, thoraces; D, gut loop and gonads; E, larva. Scales; A, 1.0mm; BE, 0,imm. being present in more or less similar numbers. They have 7-11 moderately long conical rays in optical transverse section, The ray length/spicule diameter ratio is about 0.3. Most colonies were bright red to pink in life. ZOOIDS. Zooids are relatively small being about [1.5mm long, including the long cylindrical branchial siphon which sometimes (SAM E2654) is up to 3 times the length of the body and is never less than half the Jength of the thorax. Conspicuous projecting columnar epithelial cells on the thorax may contribute to the tight hold that the test has on the zooids. Six short, sharply pointed lobes are on the rim of the branchial aperture. The atrial aperture is siniple and sessile. Asmall lateral organ is on each side of the thorax. A retractor muscle projects out into the test from about halfway down the oesophageal neck. The distal part of the gut loop is flexed ventrally. Testes are mature in the holotype and in the specimen [trom the Eyre Peninsular (SAM £2651) collected in February, The testis is undivided, and is surrounded by 9 close coils of the vas deterens. Almost spherical, large larvae are in the paratype (SAM E2696), The trunk is 1.2mm long with the short tail wound barely halfway around it. Twelve or more long, club-shaped ectodermal ampullae are along cach side of the 3 antero-median adhesive organs. As the larvae 224 mature the number of ectodermal ampulla appears to increase by division and also by additional ones developing from the prolongation of the frontal plate ventrally. A large, projecting horizontal lateral ampulla extends back from the neck region on the left side of the larval trunk. The oozooid in the centre of the trunk has 3 rows of stigmata and a long narrow, vertical gut loop stretched through the thickest part of the larval trunk. Blastozooids are not present. REMARKS. The species is characterised by its lobed, fleshy often complex colonies with terminal cloacal apertures, thick surface layer of test, long branchial siphons, extensive horizontal posterior abdominal cloacal cavity and numerous vas deferens coils. The large larva, without blastozooids and with a relatively large number of lateral ampullae also is unusual. Other lobed colonies from southern Australia with terminal common cloacal apertures are D. fragum, D. pectenand D. sucosum. The colony of D. fragum is |\-3 lobed, has smaller spicules and fewer (6) larval ectodermal ampullae per side; D. pecten has numerous lobes that do not fuse with one another as they do in the present species, and its larvae are smaller with only 5 lateral ampullae per side. D. sucosum has larger spicules with more rays than the present species. Although D. cygnuus, D. elongatum, D. macrosiphonium and D. guttatum all have long branchial siphons they are not longer than the thorax, as they sometimes are in the present species. Further, D. macrosiphonium has larger zooids, and smaller spicules which like D. elongatum, are of 2 different sorts. D. cygnuus and D. guttatum have fewer spicule rays. D. patulum resembles the present species in its spicules (some larger ones having fewer rays than others) and their distribution (becoming sparse in the basal test). However the spicules of D. patulum generally are smaller, it lacks a long branchial siphon and its grey beige pigmentation forming a network in the surface further distinguishes it. D. lissoclinum has similar colonies but lacks the long branchial siphon and has spicules crowded throughout. Tropical D. caesium has similar spicules of comparable size and it has fleshy colonies. However its single layer of spicules is beneath a conspicuous bladder cell layer, its dark pigment persists in preservative, its large zooids do not have the long branchial siphons of the present species and it has long, bifid, atrial lips. MEMOIRS OF THE QUEENSLAND MUSEUM Leptoclinides comitus from Port Davey has similar, fleshy colonies with spicules in a surface layer and few elsewhere. It is distinguished from the present species primarily by its generic characters, and by its globular spicules (rather than large stellate ones). Didemnum perplexum sp. nov. (Figs 107, 170F; Pl. 13D—F) Didemnum makropnous Sluiter, 1909: 56 (part, ZMA TU461.2. statn 99), Didemnum albopunctatum Sluiter, 1909: 58 (part, ZMA TU433.1 statn 273). Didemnum jedanense Sluiter, 1909: 58 (part, ZMA TU454.2 statn 273). Didemnum rodrignesi Rocha & Monniot, 1993: 261 (part, specimens from New Caledonia), ? Didemnum granulatum: Rocha & Monniot, 1993: 261, TYPE LOCALITY. Queensland (filter of sea water intake, Heron I. Research Station, coll. P. Kott et al., 5.3.93, holotype QM G308117; Wistari Reef Capricorn Group 15m, coll. P. Kott et al., 11,3.93, paratype QM G302960; eastern end Heron I. reef, coll P. Kott 9.3.93, paratype QM G308046). FURTHER RECORDS. Queensland (Heron [., QM G308033, G308208, G308212, G308228-9; Swain Reefs, QM G305622, G305751, G305796-7, G305803, G305807, G305649, G305698-9, G308398). PREVIOUSLY RECORDED. New Caledonia (Rocha & Monniot, 1993). Indonesia (ZMA TU433.1, TU454.2, TU461.2 Sluiter, 1909), COLONY. Colonies usually form thin, hard encrusting sheets (on the undersides of boulders) that break up readily. Many specimens have minute spicule-filled papillae crowded on the otherwise smooth surface of some parts or all of the colony. There is not a superficial bladder cell layer. Minute dark spherical pigment cells are in the test mixed with spicules. Pigment distribution is interrupted by short, narrow lines of white spicules that create the reticular pattern often seen on the surface of the colony. The dark vermilion pigment is especially crowded around the rim of the common cloacal apertures, where the spicules are missing. The zooids also are strongly pigmented and can be seen through the surface test where the spicules are less crowded over the zooids. Spicules continue down into the lining of the branchial siphons and seen from the surface a margin of spicules usually lines the stellate branchial apertures. Spicules are crowded throughout the colony, which is hard and brittle. Living 2 colonies ; are coral red®, orange chrome", orpiment orange", scarlet®- or orange- vermilion®, flame scarlet® or vermilion®. Dark spots occur where the dark oran ge, scarlet™ to claret brown", or burnt carmine™ zooids show THE AUSTRALIAN ASCIDIACEA 4 FIG. 107, Didemnum perplexum sp. nov. (A,B, QM G308046; C, QM G308117)—A, thorax; B, gut loop and gonads; C, larva. Scales: 0.1mm. through the branchial apertures causing the colonies to be described as ‘spotted.’ The common cloacal cavity is thoracic, but it varies in depth, sometimes being shallow with the zooids largely embedded in the test, while in other specimens it is deeper, the thoraces and sometimes the whole zooid being suspended between surface and basal layers of test across the cloacal cavity in its own test sheath. Spicules are up to 0.06mm diameter with 5—7 and sometimes 9 rays in optical transverse section, They sometimes have blunt-tipped and occasionally almost rod-like rays, but most often the rays, although quite long with a ray Nh i) wn length/spicule diameter ratio to 0.4, are conical and pointed. In preservative the colonies are brownish- yellow on the surface, and cream internally with yellowish or orange or brownish-orange zooids. Darker tones of orange are in the buds and endostyle, and eggs also are dark-orange. The preservative is stained a lemon-orange to yellowish-brown urine colour and labels often are stained. ZOOIDS. Zooids are relatively robust, especially the abdomen. The thorax is turnip-shaped, a moderately long branchial siphon has 6 shallow lobes around the aperture and the atrial aperture is wide and open, exposing much of the branchial sac directly to the cloacal cavity. In the branchial sac, 8 stigmata are in the anterior row, the second row contains 7 stigmata, the third 6, and the fourth row has 5. The retractor muscle is thin and is free of the zooid from about halfway down a relatively long oesophageal neck. The gut loop is open, the whole loop curved up horizontally, but also the pyloric part of the loop is bent ventrally to form a double loop. The duodenum is long and inflated at its distal end, the posterior stomach is small, and the rectum long and narrow. The gonads lie against the ventrally flexed post- pyloric part of the gut loop. The testis is dome-shaped with 7 coils of the vas deferens around its outer surface. Larvae are present in the surface test of colonies collected from Heron I. (QM G308046, G308117) in March and from the Swain Reefs (QM G305803, G305807) in July. They appear to be liberated through the surface of the colony. They also are known from the New Caledonian material (Rocha & Monniot, 1993). They have a trunk 0.6-0.88mm long, 6 pairs of lateral ampullae — 12 in all, arranged in a circle around the 3 adhesive organs and a tail that curves about two-thirds of the way around the trunk. REMARKS. The Brazilian D. rodriguesi Rocha & Monniot, 1993, to which the New Caledonian specimens were assigned, differs from the present Pacific species in its smaller spicules. The largest spicules tn D. rodriguesi are only half the diameter of the largest spicules in the present species.The reticulate appearance of the surface, which Rocha & Monniot (1993) believe is characteristic of D. rodriguesi, is seen in other species (D. moseleyi). It is more an optical illusion than a definite pattern, resulting from the crowded spicules sometimes appearing to be in short random rows. It occurs especially when 226 pigment is mixed with spicules rather than being crowded in a layer above the spicules. The absence of a posterior stomach is also an implied characteristic of the species Rocha and Monniot described. However, the definition of posterior pyloric sections of the gut is always subject to the condition of the gut when the organism was fixed. Similar variations in the condition of the gut loop are commonly encountered. Zooids with inflated gut in which the constrictions between the parts are not present, as well as narrower, less distended intestinal tubes are found in the newly recorded colonies. D. granulatum is distinguished from the present species (and from D. rodriguesi) by its smaller zooids, and 4 (rather than 6) pairs of larval lateral ampullae per side. Rocha & Monniot (1993) distinguished D. rodriguesi colonies from D. granulatum by the absence of spicule-filled papillae on the surface and the more intense colour of the colonies. Such papillae are variable in both species (and many others too) and the colour of the colonies is affected by their distribution on the surface. Neither colour nor the papillae are reliable distinguishing characters. The strong dorsal pharyngeal muscles are a family character. D. granulatum lacks the intense opaque colour of the present species and has thicker, less brittle colonies and smaller zooids. D. candidum also has smaller spicules, most with rod-like rays, D. captivum Monniot, F. & Monniot, C., 1997 has similar spicules and zooids to the present species, but has more coils of the vas deferens and more larval lateral ampullae. D. /acertosum has different spicules altogether with longer rays. D. membranaceum has white spicules exposed around the numerous prominent common cloacal apertures, smaller zooids, more sharply pointed spicule rays and occasional spiky (sometimes giant) 4-6 rayed spicules. In D. clavum spicule rays are longer, rod-like, and it also has giant spiky spicules. D. fuscum has longer, more rod-like and more numerous spicule rays. D. tonga: Kott & Goodbody, 1981 has similar spicules, but with more rays and some giant spiky ones. It has 7 coils of the vas deferens, and pointed spicule-filled papillae on the surface but only 4 pairs of lateral larval ampullae. It is conspecific with D. membranaceum. The species characteristics, evident in the newly recorded specimens and in those from Indonesia and New Caledonia are the spicules, with 5—7 and sometimes 9 conical rays, zooids with the post pyloric part of the gut bent up to form a double loop, 7 coils of the vas deferens MEMOIRS OF THE QUEENSLAND MUSEUM (within the range 6 to 9 reported for the New Caledonian material), larvae with 6 ampullae per side, and darkly stained preservative. Didemnum poecilomorpha Monniot & Monniot, 1996 (Figs 108, 168B; Pl. 13G) Didemnum poecilomorpha Monniot & Monniot, 1996; 160. Didemnum viride: Kott, 1982a: 101, NEW RECORDS. Western Australia (Broome, QM G308485). Papua New Guinea (Gazelle Peninsula, QM G302890). PREVIOUSLY RECORDED. Western Pacific (Philippines— QM GH483, GH488 Kott, 1982a; Palau Is— QM GH498, GH501 Kott, 1982a; Monniot & Monniot, 1996; Indonesia — Monniot & Monniot, 1996). COLONY. Colonies are tough, leathery, encrusting sheets with the surface marked into slightly elevated zooid-free longitudinal streaks and oval to circular opaque areas by slightly depressed translucent lines over narrow primary common cloacal canals that are lined on each side by zooid openings. The preservative is stained green and pools of blackish-green pigment and groups of green cells are in the basal test. Spicules sometimes are relatively sparse in the superficial layer of test where they are mixed with bladder cells and plant cells, They are crowded at zooid level and throughout the remainder of these tough, solid colonies, although in one colony (QM G308485) the lower one-third (beneath the embedded abdomina) is transparent and spicule-free. The translucent lines over the common cloacal canals result from the lesser depth of spicule-containing test there than in the solid areas of test they surround. Spicules are of 2 types, stellate ones to 0.0625mm diameter with 11-13 pointed conical rays in optical transverse section and others with flat-tipped to rounded rays that are never as large as the stellate ones. The ray length/spicule diameter ratio of the stellate spicules is about 0.25. ZOOIDS. Zooids are relatively small, to about 1.0mm long overall including a long branchial siphon sometimes almost as long as the thorax. Six sharp points are around the branchial aperture. The atrial aperture is a wide, rectangular opening around the branchial sac. The oesophageal neck is at least half, and the remainder of the abdomen is only about one-sixth of the total zooid length. The retractor muscle is particularly long and tapering, free of the oesophageal neck about two-thirds of the distance down it. The lateral organs are small THE AUSTRALIAN ASCIDIACEA 4 227 FIG, 108. Didemnum poecilomorpha (A,D-F, QM G302890; B,C, QM G308485) — A, vertical section through colony; B, zooid dorsal view; C, lateral view; D, larva with symbionts in larval test; E,F, anterior end of larvae showing variations in adhesive organs. Scales. A, 0.5mm; B-F, 0.1mm. goblet-shaped projections from each side of the parietal thoracic wall opposite the last row of stigmata with their concavity directed ventrally. About 6 stigmata per row are in the branchial sac although these could not be counted exactly. The post-pyloric part of the gut makes a tight double loop in the distal tip of the abdomen. The conical to dome-shaped testis is behind the loop and 8 coils of the vas deferens surround it. A large spherical greenish-coloured egg is present in the abdomen of the western Australian specimens. Embryos are developing in the basal test of the specimen from Papua New Guinea (collected in November). They move up toward the surface as they mature. The larval trunk is about 0.6mm long and is a deep, regular oval. The tail extends about two-thirds of the way around the trunk. Five rounded ectodermal ampullae are along each side of the antero-median adhesive organs. In 6 examined larvae, 3 have only 2 adhesive organs, 2 have the dorsal one partially subdivided and one has 3 separate adhesive organs as a result of the dorsal one subdividing. Nevertheless both Kott (1982a) and Monniot & Monniot (1996) found 3 larval adhesive organs. The larval test is filled with plant cells except for windows over the ocellus and otolith and in front of the adhesive organs. REMARKS. The newly recorded specimens and the type material from Indonesia have similar colony form, arrangement of spicules, form and size of the stellate spicules, zooids, cloacaaal systems, similar sized larvae with 5 pairs of ectodermal ampullae and they all have plant cells embedded in the larval test leaving clear windows over the sensory and adhesive organs. On re-examination, specimens from the Philippines and Palau Is, which Kott (1982a) assigned to D. viride, were found to contain globular as well as stellate spicules as in the newly recorded material. The globular spicules, which are patchy in their distribution, were not reported by Monniot & Monniot (1996). The colonies, small zooids with long oesophageal neck, branchial siphon and 2 sorts of spicules do resemble D. guftatum, however the more numerous spicule rays, slightly larger 228 zooids and the more numerous larval ectodermal ampullae distinguish the present species. Didemnum precocinum sp. nov. (Figs 109, 165G; Pl. 13H) ?Didemnum fragile Sluiter, 1909; 56 (part, ZMA TU446, 1A). ?Didemnum candidum: Hastings, 1931: 94 (part, pink shore specimens). TYPE LOCALITY. Queensland (Wistari Reef, landing stage, low tide rubble fauna, coll. P. Kott 5.3.93, holotype QM G308026; Heron I. reef, eastern end, low tide rubble fauna, coll. P. Kott March 1993, paratype QM G308028). FURTHER RECORDS. Western Australia (Ashmore Reef, WAM 521.92; Lesueur I. Kimberley, WAM 720.91). Queensland (Capricorn Group, QM G302977, G308156, G308496; Swain Reefs, QM G308368; ? Low Is — Hastings 1931). ? Indonesia (Sluiter, 1909). COLONY. Colonies, never more than 2mm thick, are sometimes extensive sheets and always are flat and hard with large common cloacal apertures on randomly distributed shallow elevations of the surface. Some Prochloron is present on the surface. Spicules are crowded throughout, although sometimes there may be pigment cells scattered amongst them. In life, colonies are flesh coloured to whitish pink or orange, sometimes being described as orange spotted when the flame scarlet to cadmium orange zooids show through the branchial apertures. The common cloacal cavity is deep, the thoracic test sheath is only a very thin ventral strip, and almost the whole of the perforated pharynx is presented to the cloacal cavity The surface layer of test is very thin but the basal layer is thicker, containing abdomina and some zooid-free test. The surface of the colony some- times has a fluffy appearance but when spicules are more crowded it is hard and branchial apertures are depressed into the surface, dimpling it. Colonies are white in preservative with white to beige or yellow zooids. A bladder cell layer was not detected. Spicules are spherical, and globular, generally to 0.04mm but occasionally to 0.06mm in diameter, with thin, crowded, radially arranged rod-like, flat- to round-tipped rays. The spicules are crowded in the test and are not interrupted around the stellate apertures. ZOOIDS. Zooids are small, the thorax only 0.3mm long and the abdomen about the same size, Six distinct pointed lobes surround the branchial aperture. The atrial aperture is wide and most of the branchial wall is directly exposed to the cloacal cavity. A narrow atrial tongue, slightly bifid at the tip, projects from the upper rim of the MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 109. Didemnum precocinum sp. nov. (QM 308026) -—A, thorax; B, gut loop and gonads; C, larva. Scales: 0.1mm. aperture. A tapering retractor muscle is free from about halfway down the oesophagus. In the branchial sac 6 stigmata are in the anterior row, the next 2 rows have 5 each, and the last row has 4. The gut loop is relatively short, the ascending limb looping up over the gonads. The testis is hemispherical, its outer surface completely covered by the 6 coils of the vas deferens. Larvae are present in specimens collected in March (QM G308026, G308028, G308156). The deep larval trunk is 0.7mm long with the tail curved a little more than halfway around it. Four or 5 lateral ampullae, along each side of the 3 antero-median adhesive organs, subdivide to 8 — 10 lateral ampullae per side in the fully developed larva. A large horizontal ampulla is on the left side of the trunk. A blastozooid is present in the THE AUSTRALIAN ASCIDIACEA 4 larval trunk. Some larvae are being released into the cloacal cavity (QM G308156). REMARKS. The larva of the present species, with its numerous lateral ampullae and a blastozooid, is reminiscent of Polysyncraton. In Didemnum this type of larva is known for D. arancium, D. chartaceum, D. jedanense, and D. levitas from which the present species is readily distinguished by its spicules. D. albopunctatum and D. fragile have similar (albeit smaller) globular spicules to those of present species, and their colonies show the same colour variation (white, grey, orange, vermilion). In D, albopunctatum, magenta is a fourth variant. Colour does not appear to constitute a species distinction. However, in addition to its different larva, D. precocinum has fewer vas deferens coils than either D. albopunctatum or D. fragile. The pink shore specimens of D. candidum: Hastings, 1931 from Low Is (Thalamita Flat and R.C.: see Stephenson et al., 1931) possibly are specimens of the present species, having burr-like spicules crowded throughout. Other specimens Hastings (1931) assigned to D. candidum, viz. the white colonies with less crowded spicules (possibly D. fragile) and the dredged specimens with stellate spicules, are not conspecific with D. precocinum. Didemnum psammatode (Sluiter, 1895) (Figs 110, 168A; Pl. 14A-D) Leptoclinum psamathodes Sluiter, 1895; 171: 1905b: 20. Leptoclinum psammatodes: Sluiter, 1905a: 103. Didemnum psammatodes: Sluiter, 1909: 46; 1913: 75. Michaelsen, 1919: 14 (part, vars guinense, skeati). 1920: 22 (part, vars skeati, typicum), Hastings, 1931: 95. Kott, 1962: 326 (part, var. skeati); 1981: 173; 1998: 83. Eldredge, 1967: 200. Didemnum? psammatodes: Millar, 1956; 922. Hypurgon skeati Sollas, 1903: 729. Herdman, 1906: 337. Hypurgon fuscum Oka, 1931: 287. Didemnum fuscum: Tokioka, 1953: 192. Not Didemnum fuscum Sluiter, 1909; 52. Didemnum dorotubu Tokioka, 1967: 74. NEW RECORDS. South Australia (Yorke Peninsula, SAM E2611, QM G300972). Queensland (Capricorn Group, QM G308143, G308148, G308177, G308276, G308328; Swain Reefs, QM G305370, G305414, G305596, G305808; Whitsunday Is, QM G300943; Bowden Reef, QM GHS5352; Lizard I., QM G308448). Northern Territory (off Cape Wilberforce, QM G302903). PREVIOUSLY RECORDED. Victoria (Western Port, MV F68746, F68756 — Kott, 1962). Queensland (Moreton Bay, Sarina—Kott, 1962; Low Is— Hastings, 1931; Torres Strait—Kott, 1962). Indian Ocean (Red Sea—Sluiter, 1905, Michaelsen, 1920, Millar, 1956; Sri Lanka — Herdman, 1906). Western Pacific (Thursday I. — Sluiter, 1895; Indonesia — Sluiter, 1909 1913, Sollas, 1903; China, 229 Philippines — Tokioka, 1967; Japan — Oka, 1931, Tokioka, 1953; [faluk Atoll — Eldredge, 1967; Fiji—Kott, 1981). The species is a common component of the rubble fauna at most locations on the Great Barrier Reef and on many substrates at mainland locations. However, being relatively easy to identify in the field, it is seldom collected and, in this case, the small number of new records (referring only to specimens actually in collections) is not, an accurate reflection of its occurrence either in tropical or temperate regions. COLONY. Colonies form thin encrusting sheets, although sometimes they are produced into fleshy lobes, or have irregular twig-like branches up to 8cm long and 1cm diameter (QM GH5352, G300972) and one colony (QM G300943) is a mass of cylindrical stalks that branch and coalesce forming a three-dimensional reticulum. All have characteristically restricted thoracic common cloacal cavities and the test, including the central test in the cylindrical stalks, has faecal pellets embedded throughout. Colour varies according to these crowded faecal pellets. In coral reef habitats colonies are opaque and cream coloured, in muddy habitats they are brown. Often, Chlorophyta are embedded in the surface, as well as in the basal test, amongst the faecal pellets. A conspicuous superficial layer of bladder cells is on the surface. Spicules are never crowded, and are most numerous in the surface test around the branchial apertures. They are small, never exceeding 0.035mm in diameter, and diverse. Some have 11-13 relatively short, conical pointed rays, their bases separated from one another on the central spherical test mass; and others are burr-like with more numerous, much longer and cylindrical, or fusiform, or paddle-shaped rays and a ray/spicule diameter ratio about 0.4. Sometimes the long, pointed rays are different lengths. Cloacal canals are shallow and thoracic. ZOOIDS. Zooids are minute, less than 1mm long. The atrial aperture is wide, exposing much of the branchial sac directly to the cloacal cavity. The branchial sac has 8 stigmata in the first row but numbers in other rows could not be counted accurately. The retractor muscle is free from halfway down the oesophagus. The gut loop is bent at right angles to the long axis of the thorax. The testis is a wide lens-shape, with the vas deferens wound around its outer surface 6 times. The larva has been reported in specimens collected from Heron |, in September (QM G308276), the western Pacific in October (Eldredge, 1967), Mozambique (Millar, 1956). The larval trunk is about 0.4mm long, 4 lateral 230 MEMOIRS OF THE QUEENSLAND MUSEUM scattered around branchial apertures in surface test and oval faecal pellets; B, thorax; C, gut loop; D, larva. Scales: A, 0.5mm; B—D, 0.1mm. ampullae are on each side of the 3 antero-median adhesive organs, an otolith and an ocellus are present, and the tail is wound two-thirds to almost the whole way around the trunk. REMARKS. Although Eldredge (1967) was of the opinion that the pellets embedded in the test are not faecal, they appear to be composed of the type of sediment that prevails in each respective habitat, which supports the view that they are. The proposed synonymy (with the present species) of species without enclosed faecal pellets in the test (Michaelsen, 1920; Kott, 1962; Eldredge, 1967) is unjustified, as the small size and form of the spicules and their distribution in the surface test around the branchial apertures and the presence of faecal pellets are unique. How faecal pellets are incorporated into the test rather than being released into the common cloacal cavity is not known. The spicules with long rays of slightly different length resemble those of D. fucatum but are smaller and the rays are more numerous. The spicules have more rays and are also smaller than those of D. jedanense and D. theca which they otherwise resemble. D. stercoratum Monniot & Monniot, 1996 has similar small zooids, larvae, spicules and faecal pellets in the basal test. However, in the present species faecal pellets always are crowded throughout and the species are not considered conspecific. Sluiter (1909) drew attention to his initial mistake in the spelling of the species name. Didemnum roberti Michaelsen, 1930 (Figs 111, 172B; Pl. 14E—H) Didemnum roberti Michaelsen, 1930: 516, Kott, 1998: 83 (part, Shark Bay only). Not Didenmum roberti: Kott, 1976; 68; 1998: 83 (part, Great Australian Bight and Bass Strait records ) FIG. 112. Didemnum scopi sp. nov. (A,B, QM G308110; C, QM G308219; D, QM G308221) — A, thorax; B, ventral view of abdomen; C, dorsal view of abdomen; D, larva. Scales: 0.1mm. G308158, G308168, G308173, G308180, G308184, G308209, G308213, ? G308219; Swain Reefs, QM G308377, G308396; Barron Point, QM G302269). COLONY. Colonies are hard, encrusting sheets to slabs and occasionally small cushions with rounded margins (QM G308126). Sometimes large common cloacal apertures are on elevated ridges (QM G308116) or rounded swellings on the upper surface (QM G308168). Small spicule-filled papillae are on parts of the upper surface of some specimens (QM G308110, G308213) and others (QM G308140, G308209) have a hollow pointed papilla from the ventral side of each branchial aperture, which tends to cover the aperture when the zooid is contracted. A thin superficial bladder cell layer is conspicuous only around the margin of the colony. The cloacal cavity is thoracic, usually shallow, but occasionally deeper around a clump of zooids leaving the embedded abdomina projecting up into the common cloacal cavity (QM G308116). Branchial apertures may be conspicuously stellate with a margin of spicules or the spicules may be crowded around the openings and obscure them. The spicules usually are crowded throughout the colony, but occasionally are mixed with bladder cells creating a frothy appearance in the surface test. Sometimes they are present sparsely in the bladder cell layer and often they become sparse toward the base of the colony where they are mixed with bladder cells. Spicules are small, the largest being 0.05mm diameter, and relatively uniform, varying only in the number of long almost cylindrical or rod-like rays, 9-11 in optical transverse section. The rays have blunt pointed to rounded tips. Occasionally spicules have shorter, more conical rays separated from one another on the central mass. Although one specimen (QM G308173) is magenta, most living colonies are some shade of red (geranium red*, scarlet vermilion*, vermilion®, or dragons blood red*) or orange (orange vermilion®, orpiment orange*, saturn red*, ferruginous’). "Colonies appear spotted in life because the zooids are brighter than the overall colour of the colony, the pigment in the superficial layer of test being diluted by the white spicules that underlie it. Zooids are orange (saturn red"), burnt carmine®, red, apricot, or crimson, becoming orange and translucent in preservative. Common cloacal apertures have white rims where the red pigment is absent and white spicules are seen through the test. ZOOIDS. Zooids are small (about 0.6mm) long. A short branchial siphon has 6 points around its rim. The atrial aperture is a wide, sessile opening without an anterior lip, and a retractor muscle projects from about halfway down a long oesophageal neck. Nine stigmata are in the first 2 rows, 8 in the third row and 7 are in the last row, although these usually are obsured by con- traction. The post-pyloric part of the gut loop is bent ventrally creating a tight double loop, and the gut has the usual divisions of stomach, duodenum, posterior stomach and rectum. Gonads are present in a number of specimens (QM G302304, G308109-10, G308168, G308173, G308219, G308221). The vas deferens coils 7 times around the small testis. Larvae, present in March (QM G308110) and September (QM G302269, G308219, G308221) are relatively small (trunk length 0.55mm) with 4 pairs of ampullae and the tail wound halfway around the trunk. REMARKS. The species resembles other encrusting red or orange species with brightly pigmented zooids seen through the branchial apertures. It can be distinguished by its particularly small zooids with a long oesophageal neck, a double gut loop, and its unique spicules. Spicules are smaller than those of D. moseleyi (which also has a variety of spicules), but it lacks the globular spicules and sharply pointed rays of the latter species, and has more with long rays. D. perplexum can be distinguished by its larva and its spicules with fewer and more conspicuously conical rays. D. clavum, D. cuculliferum,. D. membranaceum and D. stragulum, which, like several specimens of the present species often have a pointed papilla ventral to each branchial aperture, have different spicules and larger zooids. D. candidum has larger zooids and distinctive spicules with fewer rays. Spicules from one specimen (QM G308219) are up to 0.03mm diameter with 11-13 rays in optical MEMOIRS OF THE QUEENSLAND MUSEUM transverse section and resemble those of D. jedanense, which differs in its cloacal systems and larvae (with numerous epidermal ampullae and a blastozooid). Didemnum sordidum sp. nov. (Figs 113, 173A; Pl. 15B,C) Didemnum membranaceunr, Kott, 1962: 323; 1998: 82. Kott & Goodbody, 1982: 518, Kott et al., 1984; 310. Monniot & Monniot, 1987: 36. TYPE LOCALITY. Queensland (Noosa Heads, Im, coll. P. Kott 02.05.61, holotype QM G4970; Heron L. north reef, coll. P. Kott 05.09.94, paratype QM G308304). FURTHER RECORDS. Western Australia (Lord Mayor Shoal, QM G300942; Pilbara, QM G300932). Queensland (Point Lookout, QM G301525; Moreton Bay, QM G308451; Caloundra, QM G308453, G308464; Bargara, Noosa, Currumbin — Kott, 1962; Heron I., QM GH899, GH1336, GH1836, G308016, G308095, G308303-4, G308318; Swain Reefs, QM G305372; Lizard L, AM Z5117). Hong Kong (QM GH163 Kott & Goodbody, 1982). Philippines (QM GH481). French Polynesia (Monniot & Monniot, 1987). Indian Ocean (Christmas I., WAM 120.93). COLONY. Most known colonies form thin, encrusting sheets. However, 2 large ones about 7cm diameter (QM G300932, G300942) consist of an erect thicket of narrow (to 5mm diameter) branches, that originate from a narrow base . The spicules are particularly crowded in the central rod of test in the branches of these colonies making a firm axis for the erect colony. Spicules are also present in the remainder of the colony, including the very thin, pigmented superficial layer of test. Round, sessile common cloacal apertures are scattered about 5mm apart over the surface and on the terminal free tips of the branched stalks. Abdomina are embedded around the periphery of the central core which is homologous with the basal test of an encrusting colony. Colonies are very hard, and the surface flat and smooth although some white streaks and low ridges occur where especially crowded spicules exclude the pigment. Some large vesicles in the surface also exclude the pigment. The test is soft and readily breaks up. Superficially a very thin coat of bladder cells and pigment is present in some parts, but pigment often is absent and white spicules are exposed. Living colonies have orange-chrome® to brownish-orange pigment in patches and long streaks alternating with streaks of white to grey which occur especially around the common cloacal apertures where pigment is absent and spicules are exposed. Zooids are vermilion*. Prochloron often is on the surface. The cloacal THE AUSTRALIAN ASCIDIACEA 4 to ee) in cavity is thoracic and relatively shallow. Spicules are crowded throughout the test and in the linings of the branchial siphons, forming a white spot in the centre of a relatively spicule-free area around each branchial aperture. In preservative, large (up to about 0.015mm diameter) brown cells with granular contents lie in the colony, around the zooids, in the common cloacal cavity and in the test. Internally they confer a dark colour on the preserved colony. Spicules are relatively large, to 0.065mm in diameter, with conical rays, 9-11 in optical transverse section. Mostly the rays have pointed tips but others are slightly rounded. Occasional spicules have fewer rays (as few as 7) with each one seated in a distinctive pentagonal base. ZOOIDS. Zooids are small, about 0.6mm when contracted. The branchial siphon is relatively long and cylindrical with 6 small points around it. The atrial aperture exposes most of the branchial sac directly to the cloacal cavity. The thorax is narrow with only about 6 stigmata in the middle rows of the branchial sac. A retractor muscle extends from a short distance down the oesophagus. The gut loop has the usual long duodenum, oval posterior stomach and a rectum that is wide at its proximal end. The distal end of the gut loop is flexed ventrally. The testis is against the posterior surface of the flexed gut loop. It is sometimes lens-shaped, but occasion- ally pointed where it joins the vas deferens, FIG, 113. Didemnum sordidum sp. nov. (A, QM G308318; B, QM G308095; C, QM G4970) — A, thorax ventrum with dark spherical cells adhering; B, dark spherical cells adhering; C, larva with dark spherical cells in haemocoel, Scales: 0.1mm. which coils 8 times around the outer half of the testis. Larvae are in the test of specimens collected in May from Noosa (Kott, 1962). They are small, the trunk being 0.35—0.45mm long. Five lateral ampullae are along each side of the 3 median adhesive organs. The large granular brown cells are in the larval haemocoel. REMARKS. Generally the characteristics of this species that help to distinguish it are the orange colour of the living colonies streaked with white and grey, the dark brown colour of the internal part of the preserved colony, the small zooids and larvae and the large number of vas deferens coils. The 2 large colonies of narrow stalk-like branches are conspicuously different from encrusting sheets. Nevertheless the colony form is the only difference detected and specimens of both forms are here treated as conspecific. The upright branches may be a growth form that occurs in more advanced colonies in response to some environmental factor such as the less restricted habitats available in deeper waters. D. fuseum has a similar larva with brown cells in the haemocoel and 5 pairs of lateral ampullae, and a similar number (9) of vas deferens coils. The present species is distinguished from it by the characteristic orange and grey colour pattern of living specimens, and the smaller spicules, with relatively numerous but shorter, broader and more distinctly conical rays sometimes set in pentagonal bases. The loose brown cells, numerous vas deferens coils and conical spicule rays occur in temperate D. spadix which is distinguished mainly by the vesicles surrounding each branchial aperture rather than being scattered in the surface. Similar brown cells also occur in other species (see Glossary, haemocoel). Some spicules resemble D. digestum, having conical tips set in a pentagonal base, but in D. digestum the rays are larger and fewer. Didemnum spadix sp. nov. (Figs 114A,B, 169E; Pl. 15D) Didemnum candidum: Kott, 1972b: 179; 1975: 9. TYPE LOCALITY. South Australia (Elliston Bay 6m, roof of caves, strong surge, coll. S. Shepherd 13.5.71, holotype SAM E2841; northern Great Australian Bight 32°24’S 133°30’E, 49m, coll. Prawn Expedition 23.8.73, paratype SAM E2694), FURTHER RECORDS. Western Australia (Busselton Jetty 6-8m, SAM E2686). South Australia (Elliston Bay — SAM E2700 Kott, 1972b); ? New South Wales (Illawarra, QM G308094). COLONY. Colonies form rather irregular fragile, thin sheets with spicules crowded throughout excluded only by the circles of about 10 large spherical vesicles that surround each con- spicuously stellate branchial aperture. The crowded spicules continue down into the siphon linings without interruption. Spherical brown pigment cells (about 0.008mm diameter) are mixed with the spicules in the test and especially are present adhering to the body wall around each zooid. In preservative the colonies are slightly brownish-yellow on the upper surface owing to patches of these brown cells that probably have escaped from the internal test. Otherwise the test is white with crowded spicules and the brown-coloured zooids show through breaks in the surface and through the branchial apertures. The preservative is stained brown, and this persists over nearly 30 years. The cloacal cavity is horizontal and thoracic, each thorax crossing it with a ventral sheath of test. The surface layer of test is thin, but the basal layer (in which abdomina are embedded) is thicker. Spicules are stellate, rarely to 0.45mm in diameter but usually less, and with 7—9 and occasionally 1] conical rays in optical transverse section. The ray length/spicule diameter ratio is about 0.35. The conical tips of the rays are set ina thick basal shaft, or in the central mass. ZOOIDS. Zooids are small, less than 1.0mm long (about 0.7mm). The branchial siphon is well developed with 6 pointed lobes around the rim of MEMOIRS OF THE QUEENSLAND MUSEUM the opening. The atrial aperture is wide and exposes the branchial sac directly to the common cloacal cavity. An atrial tongue is not present. A long, finely tapering retractor muscle projects from the upper part of the oesophageal neck. In those zooids in which the stigmata could be counted (SAM E2686), there are not more than 6 per row. The gut loop is of the usual form, the post-pyloric part bent ventrally, and the large, undivided testis, with 8 coils of the vas deferens around it, lies against the dorsal side of the ventrally flexed part of the loop. Larvae are not known. REMARKS. Although Kott (1972b) referred to dark brown zooids with blackish-brown pigment cells in the Elliston Bay specimen she had mistakenly assigned to D. candidum, this pigment is not in the re-examined specimen, and probably is lost in preservative. She recorded 8 coils of the vas deferens around an undivided testis, although these also were not detected upon re-examination. The circles of vesicles she recorded remain intact. The large vesicular cells regularly arranged around each branchial aperture resemble those of Polvsyncraton orbiculum and P. circulum. The species is a Didemnum, however. It resembles tropical D. fuscum and D. sordidum in most characters including the small zooids with relatively few stigmata, relatively numerous coils of the vas deferens and the dark spherical cells that lie free in the space between the test and the zooids and cling closely to the body wall (see Glossary, haemocoel). Spicules of the present species have about the same number of rays as D. fuscum, but are shorter and more conical (like the rays of D. sordidum). The spicule rays of D. sordidum are more numerous, and its spicules are larger (up to 0.065mm diameter). Also, D. sordidum and D. fuscum lack the large vesicular cells in the surface. A thin, flat colony with spreading margins from New South Wales (QM G308094) lacks the vesicular cells in the surface test, and the spherical brown cells in the test. Nevertheless its zooids are brownish, it has diffuse brown pigment in the surface test, and its spicules are identical with those of the present species, to which it has been questionably assigned. Didemnum spongioide Sluiter, 1909 (Figs 114C—E, 171E; Pl. 15E) Didemnum spongioides Sluiter, 1909; 67; Monniot, 1995: 326. Not Didemnum spongioides: Kott, 1962: 318; 1998: 83 (part, from Rottnest [., T. tegulunt) and 7! nubilum contain only cyanophytes (Kott, 1982a; Kott et.al.,1984; Parry, 1984a; Parry & Kott, 1988). Prochloron is the only symbiont to occur in the cloacal cavity (Parry & Kott, 1988). In T; pigmentatum non-obligate symbionts are on the surface of the colony. As in Lissoclinum, some of the Trididemnum spp. in obligate symbioses with Prochloron appear to be related (TZ: cyclops and T. paracyclops, T. clinides and T: paraclinides). Taxonomy of the Prochloron has not been resolved, so it is not known if the symbionts are the same or related species in each host species (Kott et al., 1984) or each group of host species. ‘Accordingly a symbiosis may have arisen on at least 4 occasions. However they could all have arisen independently on 7 occasions. In the larvae, the plant cells usually envelope the trunk completely, being absent only from clearly defined areas (or windows), one over the cerebral vesicle, and another in front of the adhesive organs. It should be emphasised that these plant cells are not endosymbionts as stated by Monniot (1991). They are in the colony — either in the test or in the cloacal cavity. They are never in the body of the zooids, and they certainly never are intracellular. Eldredge (1967) discussed 11 species of Indo-west Pacific Trididemnum which he divided into the cerebriforme, savignii and cyclops groups based on colony type and zooid form. Within each group, the species appear to have close affinities, and generally the relationships suggested by Eldredge’s groupings are confirmed by the dark squamous epithelium in 253 the body wall, presence or absence of the endostylar pigment cap, and presence or absence ofan atrial siphon. Within these groups, however, changes with growth from simple to complex folded colonies, variations in and loss of pigment, and variations in distribution of spicules sometimes confuse attempts to resolve species relationships. Nevertheless those characters, together with the size and form of the spicules (albeit not very diverse) and the larvae, appear to comprise the most reliable characters for species identification. The following 4 species groups each con- taining species with apparently close affinities, are modified from the groups proposed by Eldredge (1967): 1, The savignii group has species with black squamous epithelium especially over the anterior part of the thorax, usually an endostylar pigment cap in the body wall over the anterior end of the endostyle, a posteriorly directed atrial siphon and large stellate spicules (often with long arms). The vas deferens coils about 8 times around the testis and the branchial sac has 10-14 stigmata per row. T. amiculum, T. cerebriforme, T. savignii, T. areolatum, T. natalense, T. nobile and T. discrepans have a thick superficial layer of bladder cells and spicules largely confined to a layer beneath the upper surface and one on the base of the colony. 7: vahaereere, T. tomarahi, T. pigmentatum , T. sibogae and T. vermiforme have spicules generally throughout the test and, like 7. amiculum, T. cerebriforme and T. nobile , tend to form complex convoluted colonies to 10cm or more. Sometimes 7. nobile and T. discrepans colonies are aspicular. All of these species are reported to have black squamous epithelium and endostylar pigment caps but these are not always present. Their presence or absence could be artefacts of preservation and do not necessarily indicate a genetic difference. T. erystallinum, T. lapidosum and T. nube and T. spongia from New Caledonia have posteriorly oriented atrial siphons and relatively numerous stigmata and may also be members of this group, but dark squamous epithelium and the endostyar pigment cap are not yet reported for them. All except J. nube have complex colonies and 7. spongia and T: crystallinum have a posterior abdominal common cloacal cavity as do other species in the group with complex colonies. As well as these possible members, the group contains 7. amiculum, T. areolatum, T. caelatum , T. discrepans, T. natalense, T. nobile, T. pigmentatum, T. savignii, T. sibogae, T. tomarahi, T. vahaereere, T. vermiforme, and the South African 7. cerebriforme as well as T. cerebri- forme: Michaelsen 1924 from New Zealand. 2. The miniatum group contains 7. miniatum and T, nubilum, with sessile atrial apertures, algal symbionts and 3 larval adhesive organs but lacking endostylar pigment caps. 3. The cyclops group of tropical species form thin encrusting sheets or small lobulating cushions containing Prochloron in the common cloacal chamber. The atrial aperture is large and sessile, an endostylar pigment cap is always present and conspicuous. Larvae have only 2 adhesive organs. The group contains 7. cyclops and T. paracyclops. 4. The dispersum group contains species with embedded symbionts (Prochloron and other cyanophytes). Spicules have relatively short rays and sometimes are globular or burr-like (7. dispersum). There is no endostylar pigment cap, and the atrial aperture is on a short posteriorly directed siphon. The members of the group are 7. dispersum, T. clinides, T. paraclinides, T. sirigosum. Other species do not have obvious affinities within the genus and have not been assigned to a species group. Superficially, Trididemnum may be related most closely to Didemnum, which has 3 rows of stigmata in the larval oozooid, a retractor muscle, an undivided testis, a coiled vas deferens and occasionally black squamous epithelium (D. albopunctatum). However, many characters are reminiscent of Leptoclinides: some (but not all) Trididemnum spp. have more stigmata per row than Didemnum usually has; a posteriorly directed atrial siphon sometimes has 5 lobes around the aperture (7. amiculum, T. lapidosum); generally larvae are similar with a distinct waist, limited number (usually 3 or 4) of lateral ectodermal ampullae on each side; and larval blastozooids (except in T. pseudodiplosoma) are absent. However, Lepfoclinides never has a retractor muscle and usually it has numerous male follicles in the testis, 4 rows of stigmata in both zooids and oozoids and the posterior end of the larval trunk is not so narrow and pointed as in most Trididemnum spp. Black squamous ectoderm and a retractor muscle occur in Trididemnum and in many Diplosoma spp. and sometimes in Lissoclinum (L. variabile) which otherwise have different zooids and larvae from Trididemnum,. The conspicuous transverse MEMOIRS OF THE QUEENSLAND MUSEUM muscles in the parietal thoracic wall of some of the larger zooids are otherwise known only in Atriolum.Thus, hypotheses can be developed suggesting a direct relationship between this genus and most other didemnid genera, with the exception of Polysyncraton, which it resembles only in the coiled vas deferens. It is not impossible that Trididemnum, Didemnum, Lissoclinum and Diplosoma share a common Leptoclinides ancestor, and that Polysyncraton was isolated independently from Leptoclinides. Trididenmum does not appear to be particularly diverse, only about 30 nominal species being recorded from Australia and the Indo-West Pacific. KEY TO THE SPECIES OF TRIDIDEMNUM RECORDED FROM AUSTRALIAN WATERS 1. Prokaryotic symbionts in common cloacal cavity and/or INES oe erie gb bee Ws ae et oe at ee 17 Prokaryotic symbionts not in common cloacal cavity or i POSE. Set teas doe he Menees sere ewe ¥ € e 2. Black pigment cells in patches or evenly distributed amongst crowded bladdercells. 2. ......0... 3 Black pigment cells not amongst crowded bladder cells . 6 3. Spicules insubsurfacelayer... 2... 0... 000. 4 Spicules not in subsurtace layer; or aspicular 9 ike ech APNE s Cees Os cabal ceees. ods T. discrepans 4. Spiculesto0.lmmdiameterormore. 2... 0.0... 5 Spiculesto0.05mm diameter . . T. crystallinum sp. noy. 5. Spiculeraysblunt-tipped.. 2... 2... T. areolatum Spicule rays sharply pointed ......... T. savignii 6. Posteriorabdominal cavitiespresent. ......... 7 Posterior abdominal cavities not present... .... 14 7. Spicules globularand burr-like. 2... ....00.. 8 Spicules stellate oraspicular, ........-..5. 9 8. Spicules sparse but evenly distributed through colony. . ota Whakshn b tay el teem goon 8 T. spumosum sp. nov, Spicules in single layer in floor of common cloacal cavity BTS te Wee ee: Beeb ng BA ops T. tectum sp. nov. 9. Branchial siphon more than halfthe length ofthe thorax . . ag Ae gat ele EPG pita A T. amiculum sp.nov. Branchial siphon not more than half the length of the thorax | 10, Spicules with 13-15 rays in optical transverse section; never aspicular T. pigmentatum sp. nov. Spicules not more than 13 rays in optical transverse | section; sometimesaspicular............- 1 11. Colony thin sheet like; notaspicular 7. cae/atum sp. nov. Colony not thin, sheet-like; sometimes aspicular. . , 12 12. Vas deferens with 8 coils; spicules to 0,16mm diameter oe SP ho Ee T. sibogae Vas deferens with 10 coils; spicules all less than 0.1mm diameter. Pi ee) Pca hs, $s 4 13 13. Central test core present, surrounded by common cloacal CAVA se eet po Ee ee T. nobile sp. nov. Central common cloacal cavity, no central testcore . . . T. vermiforme sp. nov. THE AUSTRALIAN ASCIDIACEA 4 25 14. Spicules globular and burr-like; oraspicular . 2... . T. pseudodiplosoma Spicules stellate; neveraspicular. . 2.2.2... 24. 15 15. Spiculesto0,16mm diameter . . . T. lapidosum sp.nov. Spicules all lessthan0.lmm diameter... ..... . 16 16. Spicule rays include comb-, chisel-shaped, sometimes withdividedtips. .. 2. 0.0... T. cristatum sp. nov. Spicule rays with pointed tips, neverdivided ..... . 17, Endostylar pigment cap present; symbionts in cloacal CAVA ns eS Soe ail oh sity erg atpeey taba sae 18 Endostylar pigment cap not present; symbionts embeddedinthetest. 2.2... ..0.....00. 19 18. Vasdeferenscoils]0times ....... T. paracyclops Vas deterenscoils6times..........., T. eyclops 19. Atrialapertureonasiphon .... 2.0.2.0... 20 Atrial aperturesessile. .. 2... ...-...0048. 22 20. Spiculesless than0.08mm diameter. 2... 0... 21 Spicules to 0,08mm or more diameter . . T paraclinides 21. Colonies with highly arched upper surface; cloacal canals abdominal; stellate spicules with ray length/spicule diameterratioabout0.2.......... T. dispersum Colonies without highly arched upper surface; cloacal canals thoracic; stellate spicules with ray length/spicule diameter ratio about 0.4 T. clinides 22. Spicules stellate with conical pointedrays . . T. nubilum Spicules globular with flat-tipped cylindrical rays. . . . T. miniatum The following species known in adjacent regions are not yet recorded from Australian waters: Trididemnum cerebriforme Hartmeyer, 1913 from South Africa (see Millar, 1955), forms a complex convoluted colony with 3-dimensional common cloacal systems, a superficial layer of bladder cells, stellate spicules to 0.09mm diameter, small zooids with dark squamous epithelium and an endostylar cap, Although Australian material has been assigned to it, certain characteristics of the colony, zooids and larvae, including spicule distribution, spicule size and form, vas deferens coils, length of the branchial siphon, retractor muscle and number of larval ampullae distinguish the South African species (see 7 sibogae, T. nobile and T. vermiforme Remarks, below). 7. cerebriforme: Michaelsen, 1924 from New Zealand, has a thicker bladder cell layer than either the Australian or the South African material. Trididemnum fetia Monniot & Monniot, 1987 from French Polynesia, forms thin (1mm) encrusting colonies with a soft but firm test, and rare spicules localised around each branchial aperture, Spicules are to 0.05mm diameter, most with long and only slightly tapered rod-like rays, although some smaller ones have irregular conical rays. Larvae are small (trunk 0.35mm long) with 4 pairs of ectodermal ampullae and 3 adhesive organs. The vas deferens coils 7 times around the undivided testis and an endostylar pigment cap and atrial siphon are present. Trididemnum granosum Sluiter, 1909 from Indonesia forms small (about 0.5cm) spherical colonies with numerous pointed papillae on the upper (convex) surface. Wn Stellate spicules to 0.027mm diameter with 7-9 rays in optical transverse section are in the superficial layer of test. The species is distinguished by its small colonies and small, stellate spicules with relatively few rays. Trididemnum marmoratum (Sluiter, 1909) from Indonesia (> Leptoclinum marmoratum: see Monniot, 1994: 10) has a posteriorly directed atrial siphon, 3 rows of stigmata with 10 per row, and 6 coils of the vas deferens around an undivided testis. Three antero-median adhesive organs and a circle of lateral ampulla are in the larval trunk. Its affinities have not been determined. Trididemnum natalense Michaelsen, 1920 has a smooth investing colony, with a thick superficial layer of bladder cells containing pigment and a layer of stellate spicules (to 0.06mm in diameter with 12 rays in optical transverse section) principally beneath the cloacal canals, at oesophageal level. Eight coils of the vas deferens surround the undivided testis, and 8—10 stigmata are in each row. Its differences from 7 savignii are the spicule layer beneath the cloacal cavity (as in 7. areolatum) rather than above it (as in 7 savignii), and the relatively small diameter (0.06mm) spicules which also distinguish it from 7) areolatum. Trididemnum nube Monniot, 1991 from New Caledonia has small, translucent encrusting colonies to 6mm thick. Zooids are in oval groups surrounded at oesophageal level by large (0.08mm diameter) stellate spicules with 9-1] pointed rays in optical transverse section. The spicules resemble those of T savignii although the rays are more numerous, not so pointed and the spicules more patchy in their distribution. The zooids have a retractor muscle from halfway down the oesophageal neck. The species is distinguished from others with a single layer of spicules by the oesophageal level of that layer, the large numbers (12 pairs) of larval ampullae, the size of the larval trunk (2mm), a particularly large number (18) of stigmata in each row and isolated oval groups of zooids (like 7. crystallinum). Although Monniot (1991) referred to the absence of the blastozooids in the context of species differences, this does not constitute a distinction from other known Trididemnum spp. as only 7; pseudodiplosoma from South Australia is known to have blastozooids. Trididemnum planum Sluiter, 1909 from Indonesia forms smooth, irregular, thin sheets to 10cm, with dark brown pigment in the thick spicule-free superficial bladder cell layer. Spicules are in a crowded layer at thorax level, and a layer beneath the thoracic common cloacal canals. Spicules to 0.06mm diameter have 13 —15 short conical rays in optical transverse section. The small zooids have black squamous epithelium and an endostylar pigment cap, the short, cylindrical branchial siphons open along each side of the common cloacal canals, Short atrial siphons with smooth rounded apertures are on the anterior third of the dorsal mid-line. Recently collected specimens from Darwin Harbour (NTM E191-2: September 1999) conform with Sluiter’s (1909) account of the type specimens except for 8 coils of the vas deferens (rather than 6). Larvae, in the basal test of the Darwin specimens, have 5 pairs of slender ectodermal ampullae surrounding the 3 antero-median adhesive organs and the tail wound halfway around the 1.0mm long trunk. Crowded bladder cells are in the larval test. The species is distinguished from 7 areolatum (which also lacks spicules in surface and basal parts of the colony) by its relatively small spicules with short and numerous conical rays, its thoracic common cloacal cavity, anterior atrial siphon, black squamous epithelium and endostylar pigment cap. Trididemnum polyorchis Monniot & Monniot, 1996 has hard pinkish-brown and cream rounded colonies and stellate spicules, to 0.05mm diameter with 9-11 short conical rays. The species is distinguished by its small zooids surrounding small common cloacal chambers, sessile, open common cloacal apertures, the testis divided into 2 or 3 follicles and 4 loose coils of the vas deferens, Zooids have characters that resemble Po/ysyncraton and it is possible that the species has an affinity with that genus rather than Trididemmum, which is not otherwise known to have a divided testis or loose vas deferens coils. Trididemnum spongia Monniot, 1991 from New Caledonia, forms irregular, often massive colonies, with rounded surface elevations and internal sponge-like cavities, Spicules are an averge of 0.07mm diameter with about 11 acutely pointed conical rays in optical transverse section crowded throughout. Atrial siphons are posteriorly oriented. The larval trunk, to 0.9mm long, has 6 epidermal ampullae per side. The species is distinguished from 7. sibogae by its red zooids, relatively large larval trunk and more numerous larval ectodermal ampullae. Trididemnum strigosum Kott, 1980 from the Philippines, French Polynesia and Fiji (Kott, 1980, 1982a; Monniot & Monniot, 1987) has thin irregular colonies to 2cm long. Spicules are to 0.08mm diameter, with 7-9 conical rays in optical transverse section and are crowded throughout the colony, Plant cells, as in 7 dispersum, T clinides, T. paraclinides, T. nubilum and T. miniatum are embedded in the test, mainly above the spicules. Amongst species with embedded symbionts, 7 strigosum resembles T. nubilum and T. miniatum in not having an atrial siphon (although a siphon is in 7 disperswm, T. clinides and T. paraclinides and most other species of the genus). Spicules are similar to those of 7’ paraclinides but they are smaller, and more crowded. The larval trunk is only 0.7mm long and has plant cells embedded in the test all around the trunk, leaving windows over the adhesive organs and sensory vesicle as in Tclinides and T. miniatum. The latter species has smaller spicules to a maximum of 0.06mm in diameter, and they are never crowded throughout the colony. 7) nubilum also has small (to 0.04mm diameter) spicules that distinguish it from T strigosum. Trididemnum vahaereere Monniot & Monniot, 1987 from French Polynesia, resembles the sympatric 7. tomahari and T. pigmentatum. The latter species has larger spicules with more numerous and longer rays. T. vahaereere is distinguished from 7. tomahari by the origin of the retractor muscle from the base, rather than the top, of the oesophageal neck, and by the 3 rather than 4 ectodermal ampullae on each side of the larval trunk. 7 strigosum has dark pigment around the branchial siphon but differs in the absence of an atrial siphon and in the symbionts in the test. MEMOIRS OF THE QUEENSLAND MUSEUM T. fetia has similar colonies and atrial siphons but different spicules. Trididemnum amiculum sp. nov. (Figs 121, 174G) TYPE LOCALITY. Tasmania (39km NNE Devonport, 40°49.8’S 146°31,3°E 68m, coll. Gomon, Poore and Lu, FRV HaiKung Cruise 81-HK-1 04.02.81, holotype MV F70259). FURTHER RECORDS. NSW (E of Coogee, 5-6mls, sandy substrate, F.R.V. Thetis Statn 44, 15.3.1898, AM Z1681). COLONY. The holotype is a fragment of a larger colony. It consists of several long, vertical, irregular, cylinders to 4cm long and about Icm in diameter, each narrowing to a terminal common cloacal aperture and joined to one another along about two-thirds of their length by a flat sheet-like expanse of the colony. The specimen (in preservative) is very hard. Each of the cylindrical lobes contains a central test core, and test connectives cross the common cloacal cavity that surrounds the central core, joining it to the surface zooid-bearing layer of test. Narrow oesophageal secondary cloacal canals penetrate the zooid-bearing layer. Spicules are in a layer in the surface test and in the layer of test surrounding the cloacal cavities. Only sparse spicules are in the central core. The Thetis colony (AM 21681) is asheet-like investing colony with asmooth upper surface. The surface is raised into vertical lobes with terminal common cloacal apertures and the basal test extends up into the cental cores of the vertical lobes. The distribution of spicules is similar to the holotype with a basal layer and a thick surface layer of particularly crowded spicules (penetrated by the very long branchial siphons) but sparse elsewhere. The posterior abdominal common cloacal cavity is extensive. Spicules are stellate, to 0.1mm diameter, with relatively short conical rays, 9-11 in optical transverse section. The ray length/spicule diameter ratio is 0.2. ZOOIDS. The test is tough and the crowded, parallel zooids are almost impossible to remove from it. They are almost 2mm long, narrow and stretched between the surface and the central test, across the common cloacal cavity. The branchial siphon, branchial sac and abdomen (including the mature testis) are each about one-third of the length. The branchial siphon sometimes has a slightly bulbous expansion at its tip. Five small pointed lobes surround the atrial aperture which is on a short posteriorly oriented siphon. A long, THE AUSTRALIAN ASCIDIACEA 4 FIG. 121. Trididemnum amienlum sp. nov, (A,B,B, MV F70259; C.D, AM Z1681L) — A, colony, B, semidiagrammatic transverse section through colony lobe showing zooids at surface, posteriar abdominal cloacal cavities and embryos in central test core; C, thorax;D, abdomen: E, larva. Scales: A, |.0em; B, |.0min; E, 0.1mm. fine retractor muscle projects down toward the centre of the colony, or into the basal test (AM £1681) from the top ofthe oesophagus. The gut is a long, narrow vertical loop with the undivided testis against the dorsal surface of the distal part of the loop. Five coils of the vas deferens surround the testis. Relatively small embryos are crowded in the test connectives and in the basal test of the holotype. They move up toward the common cloacal cavity as they mature, being liberated into the cloacal cavity for release from the colony. Larvae have 5 pairs of lateral ampullae and 3 antero-median adhesive organs. An ocellus and an otolith are present, and the tail winds completely around the trunk, which is only about 0.45mm long. REMARKS, Although the holotype resembles some less convoluted colonies of the South African 7. cerehriforme and the tropical 7. sibogae, and has similar large stellate spicules and 3-dimensional cloacal systems. 7. cerebri- forme has asimilar spicule distribution, spicules becoming sparse in the central test, and 7. sibogae has a variable distribution of spicules — from even distribution throughout to almost aspicular, However, in the present species, spicule rays are shorter, branchial siphons longer, and the relatively small larval trunk has more lateral ampullae. The long branchial siphon of the present species resembles that of Didenmum elongatum, although the latter species has a crowded layer of spicules in the middle of the colony rather than in the surface. The oesophageal neck is longer in the holotype than m the sheet-like colony, and this may be a variable character, changing with growth, 258 Trididemnum areolatum (Herdman, 1906) (Figs 122A,B, 173-I; Pl. 6A) Didemnum areolatum Herdman, 1906; 337, Trididemnum savignii: Hastings, 1931: 91. Kott, 1981: 184. Trididemnum natalense: Hastings, 1931: 92. Kott, 1962: 276 (part, pigmented Bargara colony). Trididemnum banneri Eldredge, 1967: 177. Monniot & Monniot, 1987: 17. Monniot, 1991: 518. NEW RECORDS. Queensland (Hervey Bay, QM G9447; Heron I., QM G301583, G301601, G301957, G302108, G302306, G308010; Lizard I, QM G302032; Swain Reefs, QM G308426). PREVIOUSLY RECORDED. Queensland (Bowen — Kott, 1962; Low Is — Hastings, 1931). Central Pacific (Kure and Line Is — Eldredge, 1967; French Polynesia — Monniot & Monniot, 1987). Western Pacific (New Caledonia—Monniot, 1991). Sri Lanka (Herdman, 1906). COLONY. Colonies are thick (to 3.5cm), firm, cushions to extensive sheets with a smooth surface, rounded margins and irregular outline. The superficial layer of test has bladder cells mixed with black stellate to fusiform pigment cells, sometimes with some spicules. Spicules are mainly crowded in a horizontal layer around the zooids and beneath the oesophageal and deeper abdominal cloacal cavities where they are visible through the common cloacal apertures. Spicules are absent from the lower half of the colony except for a sparse layer on the base. In life, colonies are black, or grey if there are some patches of spicules mixed with the bladder cell layer. In preservative they are grey-brown to brown. Large lacunae of dark pigment are in the basal test. The common cloacal canals are at oesophageal level or sometimes abdominal, but seldom posterior-abdominal. Spicules are large, often to 0.1mm, and sometimes up to 0.15mm in diameter. They are stellate, with 13-15 blunt conical rays in optical transverse section. Ray length/spicule diameter ratio is 0.25. Crowded between the existing conical rays on these stellate spicules are flat bases of broken rays. ZOOIDS. Zooids are up to 2mm long, with the thorax, oesophageal neck and abdomen all about one-third of the length. The branchial siphon is long, penetrating the deep bladder cell layer and has 6 long, pointed lobes around the aperture. The atrial siphon, directed posteriorly from the posterior third of the thorax, sometimes has a serrated rim. A fine tapering to short and thick retractor muscle projects from the posterior end of the thorax. A circular lateral organ is on each side toward the posterior third of the thorax. The endostylar pigment cap is often obscured by the dark squamous epithelium of the thorax and MEMOIRS OF THE QUEENSLAND MUSEUM abdomen. Longitudinal muscle bands (about 15) are in the thoracic parietal wall. Eight to 10 stigmata are in each row in the branchial sac. The gut loop is long and open. The duodenum is long and wide, the short oval posterior stomach is in the pole of the loop, and opens into the wide proximal part of the rectum. A narrow con- striction surrounded by tubules of the gastric gland separates the proximal third from the distal two-thirds of the rectum. The testis is against the dorsal side of the gut loop and 8 coils of the vas deferens surround it. Larvae are in the surface test of a colony from Heron I. collected in March (QM G308010). The trunk is 0.8mm long. The tail is short and thick, wound only about halfway around it. The 3 ectodermal ampullae each side of the 3 antero-median adhesive organs are long, slender, spatulate and bent back at the tip. REMARKS. The principal characteristics of this species are its gelatinous, firm and rather thick colony (to 5mm), with bladder cells in the surface and base, pigment cells mixed with them in the surface, and large spicules with relatively short blunt conical rays in a horizontal layer beneath the bladder cell layer and in the floor of the common cloacal chamber. Zooids have dark squamous epithelium on the body wall, and an endostylar pigment cap is on the anterior end of the endostyle although often it is obscured by the dark pigment in the body wall of the zooid. The 8 coils of the vas deferens and 10—13 stigmata per row were recorded for 7. banneri Eldredge, 1967 and for the type specimen of T. areolatum (Hastings, 1931). The endostylar pigment cap is the only character that was not recorded for these synonyms. Some of the characters observed in the newly recorded specimens, including the blunt-tipped spicule rays and the slender-stalked ectodermal ampullae on each side of the larval trunk are reported for 7) banneri: Monniot & Monniot (1987). However, Monniot & Monniot (1987) found some variation in the numbers (2 4 per side) of larval ampullae and the larvae (0.6—0.7mm trunk) from French Polynesia were smaller than others assigned to this species, Larvae from New Caledonia are not described. T.banneri was erected because the type specimens are different from 7. savignii: Tokioka, 1953. However Eldredge (1967) was wrong in his assumption that Tokioka’s (1953) material is conspecific with T. savignii (Herdman, 1886). 7. areolatum was not considered in this context, despite Hasting’s THE AUSTRALIAN ASCIDIACEA 4 259 Ao Wise nse COW PIG. 122. A, B, Trididemnum areolatum (A, QM G308426; B, QM G308010) — A, zooid showing endostylar pigment cap; B, larva. C-E, Tricidemnum caelatrum sp, nov, (SAM E2670) -C, part of colony showing common cloacal aperture and zooids; D, thorax, contracted; E, larva. Seales: A,B,D,E, 0.1mm; C, 1.0mm. (1931) redescription of the type. Like 7. savignii, T. areolatum has a thick surface layer of bladder cells mixed with dark pigment cells and although its spicules are a similar size to those of the former species, they do not have such sharply pointed rays and are found further away from the upper surface — nearer the middle of the colony. T. nobile has similar but smaller spicules, becoming more sparse internally, and its convoluted colonies are different. T. planum Sluiter, 1909 from Indonesia and Darwin Harbour has some characters of the present species including the layer of spicules at oesophageal level, the surface bladder cell layer, and the blunt-tipped rays of the stellate spicules, but its spicules are only to 0.06mm diameter. 7: planum: Millar, 1963 from Queensland appears to be incorrectly assigned (see T. tomarahi). T. polyorchis Monniot & Monniot, 1996 from the Palau Is has spicules to 0.05mm diameter crowded throughout, a wide, sessile atrial opening and 3 testis follicles that distinguish it. Trididemnum caelatum sp. nov. (Figs 122C-E, 175F) TYPE LOCALITY. South Australia (Great Australian Bight, SW Eucla, coll. K. Gowlett Holmes, W. Zeidler 14.1.89, holotype SAM E2670). COLONY. The colony is thin, growing around a weed stalk and other rubble. It has a pitted or embossed appearance owing to the absence of spicules in the test over and surrounding the thoraces so that each thorax appears to be in a concavity in the surface. The surface test is thin, and thin vertical partitions are between the thoraces. Spicules are absent also from large areas of test around each common cloacal aperture. They are in a more continuous layer at oesophageal level and are evenly distributed in the basal test, beneath the posterior abdominal cloacal cavity. Spicules are large, to 0.1mm in diameter, with 11-13 relatively long, tapering, conical rays in optical transverse section. The ray length/spicule diameter ratio is 0.3. The cloacal cavity is vast and posterior abdominal, crossed only by occasional connectives joining surface to basal test. It effectively divides the colony horizontally into the upper zooid-bearing half and the basal half which is free of zooids but contains the large developing embryos. ZOOIDS. Zooids are small, and particularly contracted in the holotype. The branchial siphon is short with its rim divided into 6 triangular MEMOIRS OF THE QUEENSLAND MUSEUM lobes. The atrial siphon is posteriorly directed from the posterior half of the dorsum of the thorax. A fine retractor muscle projects from the posterior end of the contracted thorax. About 7 stigmata are in the anterior row of the branchial sac, but the thoraces are too contracted for an accurate count. The gut loop is small and rounded, but gonads were not detected. Larvae are present in the basal test. The larval trunk is large (about 1mm long), particularly deep and almost spherical. The oozooid is halfway along the trunk, occupying its full depth. It has well-developed larval and adult organs. A large sensory vesicle protrudes from the upper surface of the oozooid. Three pairs of rounded ectodermal ampullae are along each side of the 3 antero-median adhesive organs, which have short thick stalks, and there is a median ventral ectodermal ampulla. The branchial sac, has 3 rows of short stigmata across it (about halfway down) leaving extensive unperforated strips of pharynx anterior and posterior to the stigmata. The gut is well-developed, its subdivisions well defined. The tail winds only about halfway around the larval trunk. REMARKS. Spicule arrangement and the vast posterior abdominal cavity are unusual characters in a thin sheet-like colony. The species resembles some of the more gelatinous colonies of T. nobile in the unusual distribution of its spicules. However, the present species has spicules with larger and more numerous and more sharply pointed rays, its colonies are not so com- plex and its zooids are smaller. 7) pigmentatum has similar spicules of a similar size, but they are crowded throughout the test. The species is unusual in not having an endostylar pigment cap but it is not impossible that this has faded in preservative. Although the gonads are not developed, and the number of rows of stigmata in these contracted zooids could not be determined 3 rows of stigmata in the larvae, and a retractor muscle together with a posteriorly oriented atrial siphon indicates Trididemnum. Trididemnum clinides Kott, 1977 (Figs 123A,B, 173H) Trididemnum clinides Kott, 1977: 617; 1980: 5; 1981; 186 (part, not specimens from Mambualau and Dravuni < 7. paraclinides); 1982a: 109; 1984: 519; 1998: 91. Monniot & Monniot, 1987: 18. Parry & Kott, 1988: 151. Trididemnum viride: Tokioka, 1967; 87 (part, zooids with atrial siphons). Trididemnum sp. Eldredge, 1967: 184. THE AUSTRALIAN ASCIDIACEA 4 26] FIG, 123..A, B, Tridideninum clinides (after Kott, 1980. QM G12620). A, colony; B, zooid. C —E, Trididemmwnr cristatum sp. nov. (C.D, MV F'70208; E, AM Y2321)-C. thorax: D, gut loop; E, larva. Scales: A, 0.5mm; B. 0.1mm. NEW RECORDS. Queensland (Heron 1, OM G301600, G302124). PREVIOUSLY RECORDED, Queensland (Heron I. — Kott, 1977, 1984), Philippines (USNM 11646 ‘Tokioks, 1967; Kott, 1982a). Fiji (QM G12620- Kot, 1980, 1981). Guam (Kott, 1982a). Eniwetak (Eldredge, 1967). French Polynesia (Monniot & Monniot, 1987), The species occupies cryptic habitats’ near the reef edge. COLONY. Colonies are small, almost spherical or oval, cushions to 2cm long. Larger colonies are flattened on the upper surface. Each usually contains a single system of zooids, with branchial apertures around a large central horizontal, thoracic, common cloacal cavity, with the common cloacal aperture more or less in the centre of the upper surtace. They are fixed firmly to the substrate and often are difficult to remove from it entire. The test is soft. A thin layer of bladder cells is superficial. Spicules Sometimes are crowded in the margins and base of the colony, but are sparse in the upper surface except where they are crowded in a patch over each zooid. Each branchial aperture opens near the outer margin of each of these patches of spicules. Smal| clumps of spicules surround the atrial openings into the cloacal cavity. Elsewhere throughout the colony spicules are evenly but sparsely distributed. Spicules are stellate to 0.04mm in diameter, some with round-tipped cylindneal and others with pointed conical or fusiform rays, 711 in optical transverse section. Occasionally the conical tip of a ray is supported ina wider basal section. Except for some spicules with shorter conical rays, the rays are relatively long, ray length/spicule diameter ratio being about 0.4. Prochloron, ared unicellular cyanophyte and a chlorophyte species (Kott, 1982; Parry & Katt, 1988) are embedded throughout the test, but are most crowded in the surface. The mixture of spicules and green plant symbionts in the test contribute to the cloudy mustard-green colour of these soft colonies. ZOOIDS. Zooids are about 1mm long, with a wide branchial siphon, its rim divided into 6 deep, pointed lobes. About 5 stigmata are in each of the 3 rows. A circular lateral organ is each side of the thorax between the first and second rows of stigmata. The atrial siphon is short and wide, trumpet-shaped, or often frilled, and projects laterally from the middle of the thorax. A short retractor muscle projects from the posterior end of the thorax near the base of the endostyle. The abdomen is small, with a relatively short oesophageal neck and a short gut loop. Long vascular stolons with spherical terminal ampullae extend into the test from the body wall in the ventral concavity of the gut loop. A large undivided testis is on the dorsal side of the gut loop. The vas deferens coils around it 6 times. Larvae are in colonies from Heron I. collected in June and from the Philippines in January (Kott, 1980). The larval trunk, 0.6mm long, is com- pletely enveloped in Prochloron cells, leaving naked patches of larval test over the sensory vesicle and in front of the adhesive organs. REMARKS. The colonies are distinctive with their soft test, embedded Prochloron, and soft, mustard colour. 7. miniatum, T. nubilum, T. strigosum, T. paraclinides, and T. dispersum (>T. tegulum Kott, 1984) also have embedded prochlorophytes or cyanophytes. The last two species also have the distinctive trumpet-shaped or frilly atrial siphons. 7. paraclinides forms irregular sheets and has 8 or 9 coils of the vas deferens, but otherwise has a zooid that resembles 7. clinides. T. dispersum also has similar but larger zooids. It has spicules with shorter and more separated rays, a longer larval trunk (1.0mm), dark pigment in the upper, elevated, surface of the colony, a more conspicuous bladder cell layer and the spicule size range is greater (some being nearly 0.07mm in diameter). 7 nubilum has similar spicules, but has either a sessile atrial aperture or one produced into only a short siphon, 8 coils of the vas deferens and a very tough test. 7. strigosum, known only from the Philippines, has very much larger spicules (to 0.08mm diameter), with fewer rays, crowded in the colonies, and it lacks an atrial siphon. 7. miniatum differs in its globular spicules and sessile atrial apertures. Trididemnum cristatum sp. nov. (Figs 123C—E, 175H) Didemnum mortenseni: Kott, 1954: 163 (part, specimen AM ¥2321 from BANZARE statn 115). Not Didemnum mortenseni: Kott, 1954: 163 (part, specimens from BANZARE statn 115, 1966: 286; 1977, G16 (party: TORE: 204 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 124. Trididemnum crvstallinum sp. nav. (QM G302608)— A, part of colony showing overgrowth on surface, a large common cloacal aperture, and some patches of pigment; B, thorax; C, ventral view of gut loop; D, larva. Scales: A, 2.0mm; B—D, 0.1mm. 10; 1981; 188; 1982a; 111; 1998: 91, Eldredge, 1967; 183. Tokioka, 1967; 85 (part), Thorne. Newcomb & Osmond, 1977: 575, Monniot & Monniot, 1987: 20 (part, fig, 2G 1; see also T. paruevelaps); 1996: 150. Monniot, 1991; 320, Not Trididemnum cyclops: Neweomb & Pugh, 1975: 534 (= Didemnum sp.). Lisseclinum pulvinum, Vokioka, L967; 97 (part). NEW RECORDS. Queensland (Heron |, OM G2446, G9942 G301593, G301597, G301972, G302374, 308152; Magnetic 1., QM G301594; Orpheus |, QM G301595). PREVIOUSLY RECORDED. Western Australia (Ashmore Reef, WAM 255-6.87). Queensland (Heron I. — Kott, 1962, 1977, 1980; Keeper Reef, Magnetic I., Lizard I. — Kott, 1977; Low Is—Hastings, 1931), Northem Territory (Darwin — Kott, 1966). New Caledonia (Monniot, 1991). Palau Is (Kott, 1982a), Caroline Is (Kott, 1982a). Kiribati (Tokioka, 1967). Eniwetak (Eldredge, 1967). Philippines (Tokioka, 1967). Fiji (1980). French Polwnesia (Monniot & Monniot, 1987). West Indian Ocean (Malagasy — Michaelsen, 1921), THE AUSTRALIAN ASCIDIACEA 4 Although the type location is Malagasy (Michaelsen, 1921) there have not been subsequent records from the Indian Ocean. Undoubtedly the species has been overlooked and in due course will be found in Western Australian and other tropical locations. It occupies cryptic, shaded habitats on weed, coral and rocks just below low water. It is found with other small didemnid-algal symbioses, e.g. 7) miniatum, Lissoclinum bistratum and Diplosoma virens. COLONY. Colonies are small, oval flat-topped cushions, usually less than lem long. A superficial layer of bladder cells is particularly conspicuous around the outer margin of the colony. A layer of crowded spicules is beneath the bladder cells around the outer margin, although spicules often are sparse over the upper surface, exposing the Prochloron symbionts (which are in the thoracic cloacal cavity) to the light. Spicules also are crowded in a layer in the basal test beneath the thoracic common cloacal cavity, but become less crowded toward the base of the colony. Zooids are arranged around the outer margin of the colony, their ventral border embedded in the marginal test, their dorsal borders exposed to the central cloacal cavity. From the surface, the endostylar pigment cap over the anterior end of the endostyle, and inside that, the branchial aperture of each zooid can both be seen interrupting the spicules around the margin of the colony. Spicules generally are to 0.04mm diameter although some are larger (to 0.06mm). Some are burr-like with crowded cylindrical rays, and others have 13—15 short conical rays in optical transverse section. Colonies subdivide when more than 0.5cm long, a constriction from the outer margin extending across the upper surface of the colony and dividing it from surface to base (Kott, 1980). Prochloron are the only symbiotic plant cells in this species. ZOOIDS. Zooids are to 1.5mm long. Branchial siphons are robust, the rim of the aperture divided into 6 rounded lobes. The atrial aperture is a sessile transverse opening across the middle of the thorax. The lateral organ is near the anterior end of the second row of stigmata, about halfway across the side of the body. About 7 long, rectangular stigmata are in each of the 3 rows. A fine retractor muscle is free from the upper part of the vertical oesophageal neck, near the posterior end of the thorax. The gut loop is bent ventrally at the base of the oesophagus. The rather flat undivided testis is behind the gut loop, with 6 coils of the vas deferens around it. 265 Larvae are present in colonies (QM G9942) collected from Heron I. in December and colonies from Keeper Reef in August, Fiji in July and French Polynesia (Monniot & Monniot, 1987). They are small, the trunk about 0.6-0.7mm long with only 2 antero-median adhesive organs, and 2 pairs of finger-like ectodermal ampullae. The tail is wound three quarters of the way around the trunk. The larval trunk is enveloped in Prochloron, absent from windows over the sensory vesicle and in front of the adhesive organs. REMARKS. The species is distinguished by its small colonies with single systems, endostylar pigment cap, 6 coils of the vas deferens, retractor from the upper half of the oesophageal neck, and the larvae with 2 adhesive organs, 2 pairs of ectodermal ampullae and the trunk completely enveloped in Prochloron. T: paracyclops is a related species with an endostylar pigment cap and 2 larval adhesive organs, but it has larger colonies with numerous systems, 9 or 10 coils of the vas deferens, the retractor muscle from the lower (distal) half of the oesophageal neck, a longer larval trunk (about 1.0mm long), 3 or 4 pairs of larval ectodermal ampullae and the Prochloron transferred to the next generation by a cap of Prochloron cells adhering around the posterior end of the larval trunk (as in Lisso- clinum). Monniot & Monniot (1987) assigned specimens of both T. cyclops and T. paracyclops to the former species and invoked a great degree of intra-specific variation to justify the differences observed. Certain specimens (Monniot & Monniot, 1987: 19, fig. 2C-F, H) are characteristic of 7: paracyclops, having the same large number of vas deferens coils, the same retractor muscle from the distal end of the oesophageal neck and the same large larva with a relatively short tail. Others (Monniot & Monniot, 1987: 19, fig. 2G, T) are undoubtedly 7. cyclops. Neither Monniot & Monniot (1987), nor Monniot (1991) recorded the position of the plant cells on the larval trunk. Further although the posterior end of the trunk above the tail protrudes slightly, it is not a rastrum as they state (the rastrum being a J-shaped outgrowth of the larval haemocoel and trunk wall in certain Diplosoma spp.). The small dorsal branchial lobe reported to be characteristic of T. cyclops (Monniot & Monniot, 1987) was not observed in the Australian material. T. cyclops: Monniot & Monniot, 1987 is said to be distinguished by the position of its lateral MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 125. A-C, Trididemnum cyclops (after Kott, 1980. QM G9942) — A, colony from above, B, zooid showing endostylar pigment cap; C, larva. D—G, Trididemnum discrepans (D,E, WAM 199.87; F, QM G302294; G, QM G302224)—D,E, zooids vegetative phase; F, abdomen, sexual phase; G, larva. Scales. A, 0.5mm; B,C, 0.1mm; D-G, 0.2mm. organ near the dorsal end of the third row of stigmata. This has not been confirmed in any Australian material where the lateral organ is in its usual position — near the middle of the body opposite the anterior end of the second row of stigmata, its position affected by contraction of the atrial aperture. Kott (1982a) included T symbioticum Pérés, 1962 from the Red Sea in the synonymy of 7° cvclops — both having etellate spicules with conical to round-tipped rays, an endostylar pigment cap. However, 7) symbioticum, with posteriorly oriented atrial siphons, spicules crowded in the test with green plant cells, reddish pigment and embedded symbionts, is more like 7. clinides, (which lacks the endostyle pigment cap). THE AUSTRALIAN ASCIDIACEA 4 Trididemoum discrepans (Sluiter, 1909) (Pig, 125D--G; PL 1 6B) Leproctinum diserepans Sluiter, 909: 77, Trididemnnm discrepangs Katt, \98ts (82: Monniot, 199}; 520, Didemnopsis jolense Van Name, 1918; 147, Triditemmnum savignil vat, jolenve: Tokioka, 1967; 82 (part. not specimen from Florida). NEW RECORDS. Wester Australia (Kimberley, WAM 745.91 767.91; Rowley Shoals, WAM 858,83 QM Ci12131; Montebello Is, WAM 199.87), South Australia (Kingston, OM G302294), Queensland (Capricorn Group. 19OR; 49], QM €i301692, G302224; Sue 1, OM GiI12092; Nymph |... OM G302305; Murray 1, OM G302301). Indian Ocean (Cocos Keeling, WAM 608.89), ‘Thailand (Phuket, QM G300938), PREVIOUSLY RECORDED. Australia (Green 1, - QM 412477 Kott, 1981). New Caledonia (Monniot, 1991), Fiji (Kot, 1981); Indonesia (Sluiter, 1909). Philippines (Van Name. 1918; Tokioka, 1967), Palau Is and Kiribati (Tokioka, 1967), COLONY, Colonies are gelatinous cushions to sheets with a smooth slippery surface without folds or ridges. The test is spongy with very large bladder cells. and dark pigment bodies ure compressed between the bladder cells to form fusiform to irregular branched shapes. Dark squamous epithelium is around the zoids, and lines the branchial siphon. A few large common cloacal apertures interrupt the surface of the colony. A Jarge common cloaca 1s beneath each aperture, and it spreads out into a horizontal cavity at thoracic level. Usually there are no spicules, However, WAM 199.87 from the Montebello Is has 3 groups of a few minute spicules in the branchial siphon and some sparse ones in the basal test. A specimen from South Australia (QM G302294) is said to have been red in life and the zooids have black squamous epithelium over the thoracic parietal body wall. Black squamous epithelium also is on the thorax of specimens from Cocos Keeling (WAM 608.89) and the Kimberly (WAM 765.91). The latter also have black squamous epithelium over the abdomen, ZOOIDS, Zooids are long, about 2min or more, with a Jong oesophageal neck. The branchial siphon is relatively short with 6 pointed lobes. around the opening. The atrial siphon 1s shortand directed horizontally and sometimes anteriorly, A pigment cap sometimes can be seen al the anterior end of the endostyle. A fine tapering retractor muscle of vanable length projects out into the test from the posterior end of the thorax. The thorax is particularly wide, with up to 14 stigmata in the anterior rows. The gut loop 1s open, sometimes bent ai right angles qo the longitudinal axis of the zooid, The undivided testis has 8 coils of the vas deferens, Large larvae are being incubated in the basal test of specimens collected in the Capricorn Group in December, from the Kimberley and Rowley Shoals in August and from Cocos Keeling in February, The trunk 1s 1.4mm Jong. with the tail wound halfway around it, Six ectodermal ampullae are along each side of the 3 antero-median adhesive organs. The ectodermal ampullae are curved and fattened at the tip — concave on the median surface and convex onthe outside surface, Hach has an are of columnar cells across the distal edge. REMARKS. The species is distinguished by its gelatinous, Heshy black colonies, virtual absence of spicules, large zooids, with more numerous stigmata than most species of (his. genus, and large larvae with 6 pairs of ectodermal ampullac. T. savigni? js related (with similar large bladder cells mixed with black pigment bodies in the surface), although it has a layer of large spicules beneath the pigmented surface layer of bladder cells and a smaller larval trunk, Larvae [rom Fijian colomes (Kott, 1981) are about the same size as those from the newly recorded material, Although Kott recorded only 4 pairs of ectodermal ampullae for this species, on re-examination of the material (trom Malevu) the number has been found to vary from 4 —6 pairs, Monniot (1991) did not record larvae from New Caledonia, but the specimens described appear 10 be conspecific with the present species. The larvae of colonies from Kiribati (Tokioka, 1967) are about the same size as those from other locations although, like some of those from Fiji, they have only 4 pairs of ampulla, The colony from Florida (Tokioka, 1967), 1s a convoluted colony like that of 7 sihogae — a species not otherwise known trom the Atlanti¢, and at this stage its identity is doubtful . The species has a wide range, and in Australian waters it is found in both temperate and tropical walers, Trididemnum dispersum (Sluiter, 1909) (Figs 126A,B, 174B,C) PDidenmam dispersian Sluiter, 1909, Sa. Trididemmum cispersum, Kott, 1998, 1, Trididemnunr tegulum Kot, 1984: 515, Cox etal. 19852 151, Trididenmun sp, Cteguluor’ ) Parry, l98da, 503, NEW RECORDS, Western Australia (Shark Bay, WAM 1054.83). Queensland (Heron 1, G301736, G30) 780, 268 G308012, G308315). Northern Territory (Torres Strait, South Ledge Reef, QM G300963). PREVIOUSLY RECORDED. Queensland (Capricorn Group — Kott, 1984). Indonesia (syntypes ZMA TU443.1, TU443.2 Sluiter, 1909). The species occupies the same cryptic habitats as other didemnid-algal symbioses — on weed and coral boulders near low tide, near the edge of the coral reefs. It is inconspicuous and the new record from Western Australia suggests that it may have a wide Indo-West Pacific range. COLONY. Colonies are firm (but not tough), dark brown-black, hemispherical or wedge- shaped with a raised, highly arched upper surface, to lcm in greatest dimension and to 6mm thick. They are widest near the top of the colony and narrow toward the base. Colonies probably lobulate, maintaining their small size and (usually) single cloacal system, with a large, almost sessile common cloacal aperture in the centre of the upper surface. The common cloacal cavity extends from the upper surface around the sides of the colony at abdominal level. It surrounds a central core of test that projects up from the base of the colony and sometimes forms a plug in the cloacal aperture. Clumps of spicules are in the test around the branchial apertures but these are the only spicules that invade the superficial layer of bladder cells that surrounds the colony. Spicules are moderately crowded to sparse in a thin layer beneath the bladder cells around the upper part of the colony, but are sparse, or absent altogether at thoracic level. Beneath the abdominal cloacal cavity, they are evenly spaced but never crowded and they do not form a layer beneath the superficial bladder cells around this lower half of the colony. A small group of spicules is clustered around the opening of each atrial aperture into the common cloacal cavity. Spicules are to 0.068mm in diameter, some stellate with from 7-9 short conical rays in optical transverse section, and others burr-like or globular, with crowded rod-like cylindrical, sometimes pointed or flat-tipped but sometimes round-tipped rays (like slate-pencil-urchin spines). The conical rays of the stellate spicules often break up into needle-like spines. Ray length/spicule diameter ratio of the stellate spicules is about 0.2. Algal symbionts, the cyanophyte Synechocystis trididemni (Cyanophyta) (see Cox et al., 1985), are in the bladder cell layer and the upper layers of test to thoracic level, although they tend to become progressively less crowded away from the upper surface. They are not either in or beneath the common cloacal cavity. Minute MEMOIRS OF THE QUEENSLAND MUSEUM (0.005mm) diameter dark pigment cells are also in the upper half of the colony (beneath the bladder cell layer), around the common cloaca and in large lacunae in the basal test of preserved specimens. This dark pigment causes the opaque brown-black colour in the upper half of the colony, which gradually changes to the off-white colour of the lower half where the colour results from the embedded spicules and absence of black pigment. Except for those in the bladder cell layer, the dark pigment masks the symbionts in the upper half of the colony. In preservative, the colour of the symbionts fades more rapidly than the black, or dark purple pigment cells which remain dark for a time. These also fade to white after 10 years. Small spherical or rod-shaped pink cells 0.007 —0.009mm in diameter are present among the green symbionts. Terminal ampullae of the long, branched vascular stolons are evident around the base of the colony. ZOOIDS. Zooids are 1mm or more long. The branchial siphon is large with conspicuously pointed lobes. The atrial siphon also is large, flared and directed posteriorly. A long un- perforated pre-branchial area and 3 rows of 9 long, oval stigmata are in the pharynx. A tapering retractor of varying length projects from the middle of the long oesophageal neck. The undivided testis is against the dorsal (under) side of the gut loop, which is bent ventrally at right angles to the long axis of the zooid. The vas deferens coils 5 times around the turnip-shaped testis. Larvae, in colonies collected in June but not in those collected in January or August, are large, the trunk being 1.0mm long. Cyanophyte cells embedded in the larval test obscure its structure, as usual being absent only from an area in front of the adhesive organs, and above the sensory vesicle. When the cells are removed there are seen to be 3 or 4 adhesive organs (the fourth resulting from subdivision of the dorsal one) and 2 ectodermal ampullae on each side. REMARKS. Re-examination of the syntypes (ZMA TU443.1, TU443.2) of T. dispersum (Sluiter, 1909) show it to be the senior synonym of T. tegulum. The syntypes are small colonies 5—15mm long and about 2mm thick, yellowish brown in alcohol. The test is tough, with a conspicuous superficial layer of bladder cells over a crowded layer of spicules. Spicules are sparse at thoracic and abdominal level and become sparser toward the base of the colony. THE AUSTRALIAN ASCIDIACEA 4 269 FIG, 126. A, B, Trididemnum dispersum (QM G300963)— A, thorax; B, abdomen showing oesophageal buds and stolonic yessles. C, D, Trididemnum lapidosum sp. nov.(C. QM G304634; D, QM G306111)—C, thorax; D, abdomen. E-G, Trididemnunr miniatum (after Kott, 1980. QM G12478) - E, colony; F, zooid; G, larva covered in coat of Prochloren cells. Scales: A,B,F.G, 0.1mm; C,D, 0.2mm: E, 1.0mm. Although Sluiter (1909) referred to spicules to 0.038mm in diameter, re-examination showed them to be up to 0.06mm (but generally less), most with 9-11 short conical rays in optical transyerse section, widely separated from one another on the large spherical central mass. The largest spicules are burr-like with narrow rod-like rays. Plant symbionts were not detected in the long term alcohol preserved syntype colonies. Kott (1984) compared specimens of T. tegulumt ( pay WP SS L. spongium sp.nov. 11, Spicule-free superficial bladder cell layer conspicuous L. caliginosum sp. nov. Spicule-free superficial bladder cell layer absent or IneonspiGuaMs-.-. ep Pb oe HSS. 12 12, Abdomina entirely or at least partially embedded in basal PE, arte ae ate ta pe a Te Le a Lk Me aa 13 Abdomina suspended in cloacal cavity between basal and surface test, i 5. ieteaes po eqebe ts ore ye teed a 15 13. Spicules crowded throughout; spicule rays more than 13 in opticaltransversesection........... 14 Spicules not crowded throughout; spicule rays not more than 13 in optical transverse section . L. /evitum sp.nov. 14. Common cloacal openings evenly spaced on small conicalelevations ......... L. durabile sp.nov. THE AUSTRALIAN ASCIDIACEA 4 Connon cloacal ypeniies sessile and nol evenly spaced oe l. crnulivlinm sp. nov. , Spiele Ww, (mene diennctir: With uretractarmusole. 1} regi ap) ROW, spicules fol, Hore » Gith 03min ciametery wilhout a retractormuisele. fi 16 . Colonies sivall cushions; testigundivided. . . 22. ; ; _ .. | meaendalitiesp, (OV Colonies Hin tilmigs testis 2 follicles oe 17 7, Spicules mined with blidder cells inthe surtnee al Is ; — Le dasedin Spicules crowded in the surtace _ | axtreainn) IS, Spicules Hattened, isually éncapaulato oids ' ; rot 15 ten Timosom(s dy trend Spicules not flattened, somutines encasutlan: zouids , 1 19, Spicule rays separate from one another dnd never compucted inte long arms Lo dehidosnin Spivule rays of unequal diameter, some compacted ints longarM t) A), Spreules with 4 ly X len, eompacted wony only) nm eUAlMAsS a ee 2) Spleules fot with 4 fo # lone compacted arms only, a central mass of sepurale orcompactedrays , 0... 22 2), Lateralumpollac in tarvalteuink 1 2/side Lh. davmietnenye Latcrabompullie iddarval trunk yside 2. sere sp.tioy, 22. Spicules with thick, loose rays in central mass spicules Wilhoul Mick, Mose mys La ventral pass oer oy behets 4 Syrreutes resent I COHCAVHNESP NAW Spicules not present f maulrifiaian The following species have had Australian or western Pacific specimens assigned to them in error, or have been recorded from adjacent regions, but are not known to occur in Australian waters: Lissoclinum abdominale Monniet, 1983) tron Guadaloupe is said to be conspecific with specimens, recorded from New Caledonia (Monniot, 1992), This is unlikely. Neither the Opaque triangular cells in the larval test nor the position of the spicules in a plate between the thorax and flexed abdomen are diagnostic features. ‘The: ‘wenn ¢ {Y) won a 1. tapatare former occur in-other species (eg. 1. dasmanense), The position of the spicules is presumably because they are in the strip of testalong the ventrum of the thorax — test being absent from the dorsum where the avial aperture expases the pharynx, Although they are said lo be spherical (Monnniot, 1992), both Atlantic and New Caledonian specimens have spicules with needle-like rays of unequal length like those of 7, ravarava, with which the Pacific specimens are here regarded as conspecific. Lissoelint cornutuin Monniot, 1992 front New Caledonia is One ol a group ol’ species. with follicles, pia ina circle (1. aveye group). It has large stellate spreules that distinguish it Hom other species in the group, Lissoclimine fragile (Van Name, 1902) is an Atiantie species said to occur in Western Port, Victoria (Kott, 1976), French Polynesia (Monniot & Monniot, 1987) and New Caledonia (Monniol, 1992), The Australian species is discussed below (see L, dtabile), In the type material, a relraciur muscle is absent, and probably an atrial tongue ts mesent. According to Var Nate (1902, 1921, 1945) the spicules, ralher than being only: burr- like with fine needle-like raya, somietines have fat-tipped and conical rays. The s smuller branchial sac, and the absence of" pignient in the test that characterises living specimens of the Atiantic nominal species further distinguish il from the Western Pacific L, fragile: Monniot & Monniot (1987) and Monniot, 1992 which sometimes has @ retructor muscle, usually some pigment, and has only burr-shaped spicules with needle-like rays (see L, reginiin). Lissactinnn japonieum Tokioka, 1958 from Japan and the Wwestert) Pacitte Nishikawa, 1990; Monniot, 1992), like some specimens of 1 reeinym is rose-mauve in life but lacks a retractor muscle, has numerous (6 pairs) larval ectodermal ampullue, and 3 adhesive organs, Unlike /- conehyiinn (which also is blue) it has an atrial tongue and small spicules (not more than (03mm in diameter). Mis related to L hadiwm trom the tropical western Pacific. Lissuelinum mereti Monniot & Monniet, 1987 fron French Polynesia closely resembles Z. mlangudin in its fattened spicules and undivided testis bul has larval blastozooids and 4 (rather than 6) pairs of larval anpullae, Lissoclinum multitestis (Monniot & Monniot 1996) from the Coral Sea SW of Port Moresby is distiiwuished from J... mulifichin S\uiter, 1909 by its lureer zooids (A long) more stigmata (25 per row), gastric vesicle between the ‘tuhules ol the gland and the duct, absence ofa retrachar muscle, and large (mm long trunk) larva Which, however, lacks blastozouids. Lissoctinum nolti Brewin, 1958, from Hauraki Gulf North 1, New Zealand forms thin violet to brown encrusting colonies, Spicules (to 0.04mm_ with rather irregular flat-tipped rays) are crowded in surface and base, but not between. The testis is undivided. The ovary is ina suc constricted off from theabdomen, The common cloacal cavity is the depth.of the whole zooid, A retractor muscle is not recorded, but an atrial tongue is present. /.varese Monniot & Monniot, 1987 is sintilar although it has 10 pairs of larval epidermal ampullae. while 2. neni has 4 pales. 2. reginunr has some characters of Z, neti, including its blue colotw, and similar sized spicules, but ip has a retractor muscle and the spicules have Mat-tipped rather than the irregular rays they have in £. nor. There are 2 known temperate Australian species with which L. neti could be confused, L, chawhile has a more restricted cloacal eavity than the New Zealand species, and L. esmeuriin, has smaller spicules, Both have 2 rather than one testis follicle. Lissoclinwn pacificense (Kot, 1981) fiom Fiji, has a large larval trunk (1.2mm long) like 1. tesienense. but only 6 pairs of balloon-like spherical larval Jateral ampullae. Ihe spicules have 5-7 long compactanmns with 3 tuft of short, needle-like rays in the centre (0.6mm between tips of adjacent arms), Larvae are large (trunk 1.2mm long), with 5 rounded terminal ampullae on narrow stalks along each side of the 3 antero-median adhesive organs, and 2 blastozngids, Specimens originally assigned toL pacificense included one (QM GH5%) from Dravuni and another (QM G9467) from Heron I, which have spicules with long pointed arms, but lack the central needle-like spines. This is a separate species (L. sente). Monniot & Monniot (1987), in discussing L. verrilli (Van Name, 1902) confused L. pacificense with L. philippinense (Tokioka, 1967), a synonym of L. triangulum (Sluiter, 1909), as shown by Kott (1980), who examined the types of the former species (USNM 11790-1). L. pacificense has spicules like, but smaller than, L. tuheiavae. Lissoclinum polyorchis Monniot, 1992 from New Caledonia is a member of the aureum group with a number of testis follicles arranged in a circle, It is distinguished by its diverse spicules, some with polygonal bases, in which the tips of the rays are set, resembling those of L. timorense. Lissoclinum ravarava Monniot & Monniot, 1987 from French Polynesian and New Caledonia (Monniot, 1992) resembles L. limosum, but its zooids are only partially encapsulated in spicules, it has a large open cloacal cavity with the zooids crossing it in sheaths of test, instead of being embedded in the test, and it has only 2 pairs of ectodermal ampullae (Monniot, 1992). Lissoclinum textrinum Monniot, 1992 from New Caledonia has yellow colonies, 6 larval lateral ampullae per side and the testis divided into 2. It otherwise resembles L. caliginosum, which is blue in life, has an undivided testis, some spicules more than 0.05mm diameter, and only 2 larval epidermal ampullae per side. Lissoclinum tuheiavae Monniot & Monniot, 1987 and Monniot, 1992, from French Polynesia and New Caledonia has large (to 0.18mm between the tips of arms) sparsely distributed spicules with 4 or 5 long compacted arms and a central tuft of short needle-like rays (Monniot & Monniot, 1987, fig. 18i). The larval trunk is small (to 0.6mm long) with 4 pairs of lateral ampullae, and it lacks blastozooids. Monniot (1992) claimed that the spicules are like those of L. taratara and L. philippinensis Tokioka, 1967 (Polycitorella) of the Polycitoridae, but a direct relationship between Didemnidae and Polycitoridae is not implied by this character. Hirose et al. (1996) found some phagositised Prochloron cells in test cells around the common cloacal cavity. This is more likely a response to the penetration of symbionts into the test (where they usually do not occur) than an example of stable endosymbiosis and a model for the evolution of the ancestral green plastid which these authors propose it to be. Lissoclinum reginum sp. nov. (Figs 144, 176G; Pl. 20A—D) Diplosomoides ostrearium: Hastings, 1931: 104. ?Lissoclinum fragile: Monniot & Monniot, 1987: 49. TYPE LOCALITY. Queensland (Heron I., eastern end, below low tide, coll. P.Kott 09.03.93, holotype G308077: on Halimeda sp., paratypes QM G308088). FURTHER RECORDS. Queensland (Capricorn Group, QM G9419, G302073, G302109, G302142, G302425, G302982, G308025, G308037, G308070-1, G308076, G308086-7, G308252, G308281, G308300-2, G308320, G308322-3, G308325, G308345, G308476; Swain Reef’, QM G305456, G305800, G308381; Lizard I., QM G302487). Indian Ocean (Cocos Keeling, WAM 611.89 613.89). COLONY. In life some small colonies are regular oval to irregular, magenta“ coloured plates or strips on Halimeda or coral rubble. Larger colonies are extensive (up to 0.5m) sheets stretched thinly over the bases of coral boulders. They are flax-flower blue*, violet*, magenta*, prune-purple", plum-purple® or slate grey“, sometimes with much of the upper surface dirty white or drab brown with pigment uneven, concentrated near the outer margins or around the zooid openings or in patches on the surface. Actual margins of the colony are white with crowded spicules and lack pigment. Pigment 7) i) oS cells are confined to a thin surface layer of test, mixed with and superficial to the spicules. In preservative the purple pigment changes to blackish brown with some orange pigment cells. Colonies at first look brown, pinkish-brown or beige, depending on the distribution of pigment and spicules in the upper surface. In preservative, zooids are a translucent brownish colour with brown and yellow pigmented cells in the haemocoel the brown colour can be seen through the open branchial apertures. After a long period in preservative, colonies become white. The preservative is stained a yellowish-brown colour. Large reservoirs of pigment are in the basal test, as if withdrawn from the surface. Colonies are attached loosely to the substrate and tend to grow over rubble rather than around it. Smaller plates have attachment processes stretching out around the margins of the colony. Large sheets are difficult to remove entire because they are so thin and fragile, not because they are particularly well attached. Living colonies appear to be thicker than preserved ones because the excurrent water in the vast common cloacal cavities inflates the colony. Water pressure also keeps the large common cloacal apertures raised above the otherwise smooth upper surface. Common cloacal apertures, when fully distended, often are large (to 5mm diameter). In preserved specimens these often are long slits. Branchial apertures are circular without spicules around their rims. Only the anterior part of the zooid is embedded in the surface test. Abdomina sometimes are partially embedded in the basal test, but more often the whole zooid, except the anterior part of the thorax, is suspended vertically in strands of test that cross the common cloacal cavity between the surface and basal layers. One to 3 abdomina are clumped together in a single strand of test with a thin posterior abdominal connective anchoring them to the basal test. Thoraces always are entirely separated from one another, each having a single ventral test strand continuous with the surface test. Larvae protrude, and probably are liberated, into the cloacal cavity from the basal test where they incubated. Spicules sometimes are fairly evenly distributed throughout, including the strands of test in which the zooids are suspended, although usually fewer spicules are in the surface than in the basal test. The concentration of spicules in the surface test affects the colour — fewer spicules resulting in more intensely coloured colonies. MEMOIRS OF THE QUEENSLAND MUSEUM Colonies with moderate concentrations of spicules and sparse pigment superficially appear spotted when spicules are absent over the brown zooids. Most smaller plate-like colonies have a fluffy appearance owing to relatively sparse concentrations of spicules in the often darkly pigmented surface layer of test. Spicules are burr-like and globular, to 0.04mm in diameter but usually less, with long, crowded flat-tipped or occasionally needle-like rays. ZOOIDS. Zooids are delicate and are not readily removed from the test. The abdomen, especially, is tightly enveloped in test. The branchial siphon is very short, with 6 shallow lobes and a small sphincter. The atrial aperture is vast, the whole branchial sac being exposed directly to the common cloacal cavity. An atrial tongue projects from the upper rim of the opening but this often is broken when the zooid is removed from the colony. Stigmata are large and rectangular, 9 in the anterior row, 8 in the second and third rows and 7 in the last row. The usual dorsal pharyngeal muscles are present, but delicate and difficult to demonstrate. Some fibres extend a little way down each side of the oesophagus and sometimes a very short retractor projects from the anterior part of the oesophagus. The gut forms a wide open loop. Two large testis follicles have a straight vas deferens hooked around them. Larvae are present in colonies collected in March. Four lateral ampullae are on each side of the 3 antero-median adhesive organs. The latter have deep narrow axillary cones set in par- ticularly deep epidermal cups. The larval trunk is 0.7mm long and the tail is wound halfway around it. The otolith and ocellus are well formed and 4 rows of stigmata are in the larval pharynx. A blastozooid is not present. Oval granular cells are in the larval test, especially around the posterior two-thirds of the trunk, They become less crowded anteriorly. REMARKS. The colour of the species is distinctive. Although the small fluffy (juvenile ?) magenta colonies look very different from the extensive sheets, actual morphological differences (except those associated with size) have not been detected. One specimen (QM G308302) is a very small, thin smear over the substrate. It lacks pigment altogether. Otherwise no difference from the characteristic purple colonies could be detected, except for some spherical yellow cells creating an iridescence in the branchial vessels. Some of the larger sheets lack pigment in some parts of the surface and THE AUSTRALIAN ASCIDIACEA 4 321 FIG, 144. Lissoclinum reginum sp. nov. (A, QM G308325; B, QM G308087; C, QM G308302; D, QM G308077) — A, zooid; B, thorax; C, abdomen from dorsal surface; D, larva. Scales: 0.1mm. resemble this small, colourless specimen. Fewer spicules have needle-like rays than in the possibly related L. caliginosum and L. badium. Further, the spicules of the present species are smaller than those of L. caliginosum but only slightly larger than those of L. badium. The colonies of the present species are also more brittle than the rather rubbery ones of L. badium and they lack the spicule-free superficial pigmented surface of L. caliginosum. The larvae of the present species have only 3 adhesive organs rather than the 7 or 8 in L. badium. The opaque granular bodies in the larval test are less conspicuous than in other species of the fragile group. The specimens assigned to L. fragile from 25m in the port of Noumea (Monniot, 1992), some with a small retractor muscle (see also QM G308070, G308087) are said to be white or pink, although it is not clear whether or not this is their colour alive or in preservative. Other recorded characters of colony, zooids and larvae are the same as the present species and they may be conspecific. This is more likely than conspecificity with the Atlantic L. fragile, which is characterised by its white, very brittle colonies, orange zooids in life, and conical as well as flat-tipped or needle-like spicule rays (Van Name, 1902, 1921, 1945). L. ostrearium (Michaelsen, 1930) from southern Australia has smaller spicules with fewer, thicker and less needle-like rays than the tropical D. ostrearium: Hastings, 1931. The specimens from Low Is (Hastings, 1931) are reported to have been purple when alive, and to have been growing on a linear leaf. In her description, Hastings (1931) emphasised the differences between this species and D. molle (Herdman, 1886) rather than the differences between this and other species of Lissoclinum. The large delicate branchial sac with flat epithelial cells lining the stigmata occurs in L. caliginosum and L. badium. Nevertheless the similarity between its habitat and appearance 2 i i) (including colour) establishes the Low Is specimens as conspecific with the present colonies taken on the fronds of Halimeda sp. L.vareau Monniot & Monniot, 1987 from French Polynesia and New Caledonia has a similar, thin mauve colony and the testis has 2 follicles, but it differs from the present species in the absence of a retractor muscle and its different larvae (with numerous lateral ampullae). Lissoclinum roseum sp. nov. (Figs 145, 176B,C; Pls 4C, 20E,F) ?Diplosoma ata Monniot & Monniot, 1987: 57 (part, specimens with ‘fibrous annulus’). TYPE LOCALITY. Queensland (Wistari Reef, landing stage, low tide rubble fauna, coll. P. Kott 06.03.93, holotype QM G308053; Heron I. north, opposite cay, Gorgonia Pools, low tide rubble fauna, coll. P. Kott 05.09.94, paratypes QM G308312). FURTHER RECORDS. Queensland (Hervey Bay, QM G9441, G302091; Capricorn Group, QM G11901, GH2276, G301547, G301555, G302144, G302202, G302324, G302326-9, G302506, G302520, G302553-4, G302557, G302576, G308052-3, G308270, G308309-11; Swain Reefs, QM G308369, G308420). COLONY. In life, colonies are distinctive soft, low, irregular cushions, sometimes lobed around the rounded margins. Overall they are pink, the test glassy, transparent sometimes vinaceous rufus with pink to scarlet vermilion® zooids always encapsulated in white opaque spicules. In life the thoracic capsule of opaque spicules is in 4 parts — one large ventral band, 2 latero-dorsal bands, and a short median dorsal one terminating at the atrial aperture. Uninterrupted capsules of these opaque spicules respectively surround the abdomen and the developing embryos enclosed in a brood pouch attached to the abdomen. Spicules are small (to 0.025mm in diameter) and burr-like with needle-like rays, some slightly longer than others. The transparent test is very soft and mucus- like. When undisturbed it holds its shape, but when disturbed it disintegrates readily anda layer of this mucus-like test always clings tightly around zooids and embryos and is difficult to remove. Zooids and larvae are embedded in the test. A thoracic cloacal cavity is present but is difficult to display owing to the very soft test. In preservative colonies are less delicate, the test slightly firmer, and both test and zooids are cream. One colony (QM G302327) is said to have been lemon-yellow in life, although in other respects it is similar to others of this species. MEMOIRS OF THE QUEENSLAND MUSEUM ZOOIDS. Zooids have a larger thorax, about 1mm long when relaxed. The abdomen is bent up at right angles to the long axis of the thorax. The branchial aperture has 6 moderately long pointed lobes around its margin. The atrial aperture is wide open, exposing the branchial sac directly to the cloacal cavity. A muscular annulus is in the body wall of the oesophageal neck and sometimes is very conspicuous. Although its connection with thoracic muscles was not demonstrated, it appears to consist of muscle fibres and is most likely a homologue of a similar muscle in other genera (see Remarks below). Ten long narrow stigmata are in the anterior row of the branchial sac, and these reduce to 8 in the posterior row. The stomach and posterior stomach are yellow-brown in the preserved material, but the remainder of the horizontal gut loop is colourless. An undivided testis is posterior to the gut loop and the straight vas deferens curves around its dorsal margin to extend anteriorly between the rectum and oesophagus to open near the anus. In specimens collected at Heron I. in March (QM G308053), October (QM G302324) and November (QM G302326), developing embryos are being incubated in brood pouches projecting out from the zooid — from the base of the oesophagus, near the bend of the gut loop behind the oesophageal annulus and in front of the testis. The larva has a trunk 0.9mm long with a short tail wound only around the ventral surface of the trunk. Six lateral ampullae are on each side of the 3 median adhesive organs. An oozooid (with ocellus and otolith in a protuberant cerebral vesicle) and a blastozooid are halfway along the trunk. REMARKS. The soft, translucent pink cushion- like colonies of this species are common and conspicuous, The inconspicuous spicules encapsulating the zooids, the location of the larval oozooid and blastozooid in the middle of the trunk (rather than at the anterior end as they are in Diplosoma) and the relatively large number of epidermal ampullae indicate that the present species belongs in Lissoclinum. The species shares some characters with some specimens which may have been erroneously assigned to Diplosoma ata Monniot & Monniot, 1987 from French Polynesia and New Caledonia (Monniot, 1994), viz. an undivided testis, a stalked brood pouch attached to the abdomen, a large thorax, the same number (about 10) of long delicate stigmata and an oesophageal sphincter muscle. Generally D, ata zooids have a retractor muscle, THE AUSTRALIAN ASCIDIACEA 4 323 ‘Wya00 FIG. 145. Lissaclinum roseum sp. nov. (A, QM G308312; B, QM G302324; C_OM G308053)-— A, zooid showing circum-oesophageal muscle: B. abdomen; C, larva showmg abdominal and thoracic buds and terminal columnar cells on tips of ectodermal ampullae. Scales; 0.1mm, large branchial lobes and larvae characteristic of Diplosama with oozonid and blastozooid at the anterior end of the larval trunk (see D. ferrugeum). Monniot & Monniot (1987) thought the oesophageal annulus was fibrous, and a product of the test. There is no homologue of a fibrous annulus in any ascidian. Careful examination of the structure shows it to be in the body wall (nat the test) and to consist of what appear to be circular muscle fibres. [t is homologous with a similar structure in Didemnum fucatum and L, nebulosum (in which its association with the dorsal thoracic muscle has been demonstrated) and probably in Trididemnum cyclops (see Monniot & Monniot, 1987), The species lacks the black pigment of ZL, limosuni, and its spicules are more distinctly spherical with more regular rays of even length. L, ravarava Monniot & Monniot, 1987 has a similar colony with partially encapsulated zooids but only 2 pairs of larval lateral ampullae (Monniot, 1992) and black pigment in the adult colony, Lissoclinum sente sp. nov. (Figs 146A, 1771) Echinoclinum pacificense Kot, 1981; 193 (part, specimens trom Dravuni and Heron [.); 199K: 88 (part, not wpe specimen). Lissoelinim verrill®. Monniot & Manniot, 1987: 56, TYPE LOCALITY. Queensland (Heron 1., south reef opposite cay, 8-9m, coll. P.Kott March 1975, holotype QM G9467). PREVIOUSLY RECORDED. Fiji (Great Astrolabe Group, Drayuni, QM GH59 Rott, 1981). French Polynesia (Monniot & Monniot. 1987). FURTHER RECORDS. Queensland (Heron 1., QM G308346). New South Wales (Jervis Bay, QM G10101). COLONY. Colonies are soft and grey, with white spicules in the surface and basal layers of test and sometimes more sparsely in the test connectives between them. The anterior part of each zooid is embedded firmly in the surface layer of test. Cloacal canals penetrate between thoraces, and deeper canals surround large clumps of zooids, leaving a single ligament connecting each clump to the hasal layer of test. Sometimes spicules appear to encapsulate the ventral surface of the MEMOIRS OF TILE QUEENSLAND MUSEUM FIG. 146. A, Lisswelinum senre sp. nov. (QM G9467) — A, 200id, B.C. Lisseelinum spaagium sp. nov, (B, OM GH4371: C_QM GH4372) — B, semidiagrammatic vertical section through colony showing slit-like branchial apertures and the position of zooids and common cloacal cavities; C, zooid, D-F, Lisseelinun taratara (QM GH335) -D, surface ofa portion of the colony showing branchial apertures in double lines; EB, thorax; P, gut Joop from ventral surface. Scales: A, 0.lmm; B, 2.0mm: C, E, F, 0.2mm: D. 1.0mm, thorax, but this is apparent only, the spicules being in the test and only the ventral surface of the thorax is covered by a strand of test, Spicules have 4-8 long, narrow pointed arms, without a central mass of either [ree or compacted accessory rays, They measure about 0,08mm from tip to tip of the long arms. ZOOIDS. Zooids are large, about 1.5mm long, excluding gonads, The cylindrical branchial siphon is muscular, with 6 small pointed petal-like lobes around the rim of the opening. Musculature on the remainder of the zooid is very fine, with a few longitudinal bands in the parietal body wall, and only about 5 fibres in each of the dorsal pharyngeal muscles. The transverse muscle bands between the rows of stigmata have about double that number of fibres. There is no retractor muscle, The stigmata are lined with the thin, flat epithelial cells characteristic of this genus. About |4 stiginata are in each of the rows in the delicate branchial sac, The gut forms a simple almost yertical loop. A small egg is attached to the posterior side of the gut loop by a narow ligament. In some THE AUSTRALIAN ASCIDIACEA #4 specimens yellow eggs, presumably fertile, are in the test connectives between basal test and surface clumps of zovids, but larvae are nol present in uny Of the newly recorded material. A spherical testis with the vas deferens froin its dorsal side is presenlin the material from French Polynesia, as are larvae. These have a trunk 0.64tm long, with 3 anterior adhesive organs in the anterior mid-line. The tail is wound about halfway around the trunk. Four pairs of lateral ampullae are on cach side of the adhesive organs. The sensory vesicle protrudes from the upper surface of the oozooid, about halfway along the trunk. A blastozooid is present. REMARKS, The long, narrow arms of the apicules resemble those of L. fasmanense. They lack accessory rays, either free, needle like ones like those of L. ce/veis, or compacted rays forming a central mass us in L. verril/i from Floridasand the Gull of Mexico (see Kott, 1981) and some spicules assigned to L. fufeiavee (Mommiot & Monniot, 1987, pl. 4B,C), L. rasmanense can be distinguished by the large numbers of lateral ampullae in the larvae, L. pacificense (Kot, }981)), known only trom its holotype and paratype from Fiji, has a Jarger larval trunk (!2mm long) than the present species, 6 long stalked globular larval ampullae per side, 2 blistozomids and its spicules have some needle-like spines projecting from the central muss that are nol present in L, senre. Lissoclinum spongium sp. nov. (Figs 146B.C, 176A) TYPE LOCALITY. Lord Howe I. (lagoon, sundy reet, depth lm coll, N.Coleman 23,1087, holotype QM GEL4372, paratypes OM GH4371). COLONY. Colonies are sessile, domes or regular, upright masses to 3em diameter and about 3em high attached to stalks of weed in crowded pupulalions, One to 5 rather incon- spicuous common cloacal openings are on the upper surface, distinguished from the branchial openings by their circular shape and ihe dark pigment around them. Branchial apertures are simple slits, Zooids are m a thick surface layer around the outside of the whole colony, with the exception of the base. Deep canals surround clumps of zooids and extend into narrow canals that penetrate the test around the thoraces, and into large cloacal cavities beneath the zooid layer (hut separate the central test core from the outer zooid-containing layer of the colony. The centre and base of the colony is solid zooid-free test, crowded with spicules, Spicules hecome sparse 325 in the test strands around the zooids, but are crowded again at the surtace, at the level of the branchial siphons. Spicules, to 0,025mm in diameter, are all burr-shaped and globular being composed of crowded needle-like radial rays. Prochloyonis io the common cloacal chambers. ZOOIDS. Pully expanded zooids are about 1.5mm long, excluding the gonads. The branchial aperture ts a transverse slit, with an anterior and # posterior lip, About 6 muscles radiate from each end of the apertures. Muscles in the remainder of the thorax are very delicate. The atrial aperture ts wide exposing most of the branchial sac directly to the cloacal cavity. In the isolated zooids, a vertical flap about halfway up each side of the atrial aperture is the lateral organ, The branchial sac has about 6 oval stigmata in each row und small conical dorsal languets between the rows. The gut loop is bent ventrally from the buse of the vertical oesophageal neck, the stomach, duodenum, posterior stomach and proximal part of the rectum making a horizontal loop. A large spherical testis is posterior to this horizontal loop, and the vas deferens hooks around it to extend straight to its opening near the anus at the posterior end of the thorax. REMARKS. Colonies resemble small Didemmum molle, but lack the large terminal cloacal aperture, haye slit-like branchial apertures, and less extensive cloacal cavities, and do not produce large qaantities of mucus as iL). molle. Although it shares many characters (slil-like branchial apertures, spherical spicules, undivided testis. and smal! colonies) with L. histratum its colonies are Much thicker with a ventral (rather than basal) test mass, and the spicules are smaller than those of L. Aistretuse. Lissoclinum taratira Monniot & Monniot, |987 (Figs 146D-+,, |77G) Lisseelinen tara Monniot & Manniot 1987: 32. Echmaclinum triengnim: Millar, 1975) 241, NEW RECORD, Queensland (Lizard |., QM Gil 335). PREVIOUSLY RECORDED, French Polynesia (Monat & Monniot, 1987), Indonesia (Millar, 1975). COLONY. The newly recorded colony ts sofl anu Neshy. It has a spicule-[tee superficial bladder cell layer Which sometimes is-very thick, Beneath the bladder cell layer, the spicules are mot crowded but are fairly evenly distributed, absent only from the base of the colony. Deep cireular cloacal canals extend almost the full depth of the zooids but in the newly recorded specimen there are no posterior abdominal cloacal spaces. Zooids line each side of the canals, their ventral surfaces embedded in the stands of solid test. Spicules are large, about 0.1mm between tips of the larger tetrahedral rays. Shorter and finer spicule-rays radiate out from the centre of each spicule. There is a deal of variation in the numbers and the length of the spicule rays. The spicules tend to break up. The colony is white in preservative but its colour in life is not known. ZOOIDS. Zooids are large, the thorax and abdomen together more than 2mm long. The thorax, longer than the abdomen, has a moderately long branchial siphon that penetrates the bladder cell layer. Neither retractor muscle nor atrial tongue are present. The branchial sac has 4 rows of stigmata with about 8 or 9 long stigmata in the anterior 2 rows, and 7 in the posterior row. Longitudinal muscles in the parietal body wall are very conspicuous. The gut loop is rounded but almost vertical with a roomy duodenum, an oval posterior stomach and a pronounced constriction between the proximal and distal parts of the rectum. Gonads were not present in the newly recorded specimen, In the French Polynesian specimens the testis is undivided and more or less pyramidal, with the vas deferens originating from the apex of the pyramid. Larvae are known for Indonesian material (Millar, 1975). They have a trunk 0.6mm long, with 3 adhesive organs, 4 pairs of lateral ampullae, and they lack blastozooids. REMARKS. The newly recorded specimen resembles the type material in all aspects of the colony, zooid, and spicules. The species is distinguished from L. vulgare Monniot, 1992 from New Caledonia by its larger spicules which have a more conspicuous difference between shorter narrower central rays and thicker, longer tetrahedral arms than in L. vulgare (in which all the rays are a similar thickness), The species also lacks the posterior abdominal cloacal cavity of L. vulgare. The spicules have fewer and thicker rays than those of L. calycis, and the colonies are firmer with a distinct bladder cell layer. L. pacificense from Fiji also has some similarities to this species, but its tetrahedral rays are shorter, and the central needle-like rays are shorter, and finer. Spicules of L. sente (> L. verrilli: Monniot & Monniot, 1987) have no central rays at all, its spicules resembling L. tasmanense from southern Australia. Echinoclinum triangulum: Millar, 1975, which Kott (1980) erroneously accepted as MEMOIRS OF THE QUEENSLAND MUSEUM belonging to L. triangulum (Sluiter, 1909), has spicules like those of the present species with which it appears to be conspecific. The present species is distinguished from L.mereti Monniot & Monniot, 1987 by its longer, thicker, well separated spicule rays and by the larvae, which are the same size but lack the blastozooids found in L. mereti (see L. triangulum). Lissoclinum tasmanense (Kott, 1954) (Figs 147, 177-[; Pl. 20G,H) Cystodvtes tasmanensis Kott, 1954: 155, Lissoclinum tasmanense: Kott, 1998; 88. Echinoclinum verrilli: Kott, 1962: 312; 1972a: 21. NEW RECORDS. Western Australia (Rockingham, QM G300949; King George Sound, SAM E2688). South Australia (Great Australian Bight, Fowlers Bay, SAM E2640; Topgallant 1, QM GH1288, G302149; Point Turton, SAM E2621; Edithburgh, E2626; Coobowie Bay, QM GH24 16; Tipara Reef, QM GH3705; Eyre Peninsular, SAM E2608). Tasmania (Maria I, AM Y2320). PREVIOUSLY RECORDED. South Australia (Halletts Cove, SAM E2435, E2649 Kott, 1972a). Tasmania (off Maria I., Kott, 1954, 1962). The species is said to be common in St Vincent Gulf, It is recorded to 174m (Kott, 1954), COLONY. Living colonies are soft, white and jelly-like, usually disintegrating when removed from the substrate. Spicules form a spiny tough capsule around the thorax and abdomen and sometimes are also scattered through the remainder of the test. They have 6-8 long narrow, smooth pointed arms, and measure up to 0.1mm between the tips of adjacent arms. The capsule of spicules around the abdomen is particularly compact, formed ofa single layer of spicules with their arms interdigitating and others projecting hedgehog-like around the abdomen. Embryos are found free in the test, outside the spiny capsule. Zooids are in long double rows each side of canals that are as deep as the full length of the zooid. ZOOIDS. Zooids are of moderate size about Imm overall when contracted. They are difficult to remove from the capsule of spicules. A muscular branchial siphon has 6 small pointed lobes around the rim of the aperture. At least 8 stigmata are in each row in the branchial sac, although the zooids are all too contracted for exact counts. A large circular lateral organ is on each side of the thorax. The gut loop is about half the length of the body, and oesophageal buds are present in the same colonies as developing embryos (SAM E2435). The testis is undivided. Several colonies from South Australia, THE AUSTRALIAN ASCIDIACEA 4 collected in August and December (QM GH2416, SAM E2435) and in March (SAM E2640) have embryos developing in the test. Larvae are large, the trunk about Imm long, and the tail wound about halfway around it, Three large, stalked adhesive organs, with a wide axial cone in each epidermal cup, are in the anterior mid-line. About 24 (12 per side) balloon-like epidermal ampullae on narrow stalks project from the larval epidermis around the base of the adhesive organs. These have thin epithelial walls except on their terminal surface where longer cells form a cap. The cerebral vesicle, with otolith and ocellus, is in a protuberance over the anterior end of the oozooid. Four rows ofabout 8 stigmata are in the oozooid and at least one blastozooid is present. It is possible that there is a second, although this is obscured by irregular, comma- shaped, triangular or fusiform: opaque bodies crowded in the larval test around the posterior half of the trunk, becoming sparse toward the FIG. 147. Lissoclinum tasmanense sp. nov. (A,B, SAM E2626: C, SAM E2435) — A, thorax: B, abdomen with oesophageal buds; C, larva with blastozooid, opaque cells at the posterior end of the larval trunk, and terminal columnar cells on the tips of the ectodermal ampullae, Scales: A,B. 0.1mm; C, 0.2mm, anterior end. The larval body narrows abruptly behind the oozooid and blastozooids, which are about halfway along the trunk. REMARKS. The long smooth arms of the spicules are different from mast others in this genus except L. sente (> L. verril/iz: Monniot & Monniot, 1987), which has smaller larvae with fewer (only 4 pairs) lateral ampullae, although these are similar to the balloon-like ones of the present species. L. pacificense (Kott, 1981), from Fiji, also has large larvae, but 6 balloon-shaped lateral ampullae are on each side and spicules have a tuft of short spiky needle-like spicule rays in the centre. Similar opaque bodies in the larval test to those in the present species have been observed in other species of Lissoclinum (see genus Lissoclinum above), Sometimes these are absent only from windows over the sense organs, and in front of the adhesive organs. In the present species they are crowded in the posterior half of the trunk. 328 Lissoclinum timorense (Sluiter, 1909) (Figs 148A,B, 178C—E) Didemmum timorensis Sluiter, 1909: 51. Lissoclinum timorense: Kott, 1998: 88. Didemnum voeltzkowi Michaelsen, 1920; 54 (part, syntypes ZMH K1099). Hastings, 1931: 97, Lissoclinum voeltzkowi: Kott, 1980: 13; 1981: 190; 1982a: 112. Ryland et al., 1984: 272. Monniot & Monniot, 1996: 175, Lissoclinum bistratum: Monniot, 1992: 566. NEW RECORDS. Queensland (Heron [., QM G12633; Lizard I., QM GH158). West Pacific (Solomon [s, USNM 18353). Western Pacific (Palau Is, QM GH911) PREVIOUSLY RECORDED, Queensland (Low Is — BMNH 30.12.17.43-44, AM Hastings 1931; Heron 1, Green [., Lizard I. - QM G9913, G12621 Kott, 1980; 1982a). Indonesia (paralectotype ZMA TU482, lectotype TU1274 D. timorensis Sluiter, 1909). West Pacific (New Caledonia— Monniot, 1992; Caroline Is, Philippines, Palau Is— Kott, 1982a, Monniot & Monniot, 1996; Guam —QM GH827 Kott, 1982a; Fiji — Kott, 1980, 1981). West Indian Ocean (Malagasy — syntypes ZMH K1099 L. voeltzkowi Michaelsen, 1920). Kott (1980) proposed that habitat requirements of this species are more stringent than for other Prochloron-ascidian symbioses. Vast populations are found near the low tide mark on the outer part of the open, sandy reef flat at most Fijian locations. These populations are crowded, the borders of the polygonal colonies contiguous, forming a close mosaic, At Lizard I. similar populations were found on driftwood (Kott, 1982a), but not on the reef flat, At this location L. Distratum occupies similar reef flat habitats as the present species does in Fiji. Populations at Green I. were on brown weed on the inner reef flat, and did not form such close mosaics as those directly on the sandy surface of the reef at Fijian locations. Only a few records of this species are from Heron I. and it is possible that the species cannot accommodate the diurnal changes on the reef flat at this southerly location. COLONY. Colonies are up to 0.5em thick and sometimes form large sheets to about 9cm in maximum dimension (Sluiter, 1909; Kott, 1982a) or, when found in crowded populations, small flat-topped cushions, to 4cm in greatest dimension, polygonal, with straight edges, forming a close mosaic with adjacent colonies, In less crowded populations the colony outline is more oval. Colonies appear to subdivide to form these crowded populations. In life they are dirty greyish-brown, or cream, or greenish-cream, depending on the concentration of spicules in the surface. Crowded brown-black spherical pigment cells are scattered in the surtace, and are concentrated in small evenly-spaced patches, alternating with the branchial apertures around the upper surface of each colony, just inside the rounded outer margin which is produced into pointed spicule filled papillae, one outside each MEMOIRS OF THE QUEENSLAND MUSEUM branchial aperture. Similar papillae sometimes occur on other parts of the upper surface. Newly recorded specimens from the West Pacific (USNM 18353) contain a mixture of larger sheets and small oval colonies, both with characteristic papillae around the outside of the colony. Colonies are only loosely attached to the substrate. One or 2 common cloacal apertures are on short chimneys projecting from the upper surface with pigment cells crowded around them. Branchial apertures are transverse slits. Green Prochloron in the cloacal cavity can be seen through branchial apertures in the living colonies. Spicules are crowded around the outside and in the base of the colony. They also are crowded in the surface test when the colonies are exposed, but in shaded habitats the spicules in the surface test are less crowded and green Prochloron in the cloacal cavity can be seen through the surface test. Spicules are absent from the area around the cloacal apertures. The spicules are stellate to 0.04mm in diameter with 7-9 conical rays in optical transverse section, the conical rays set in polygonal bases; or with chunky club-shaped, sometimes flat-tipped rays (the same number or more numerous than in the stellate spicules), Both the conical tip and the polygonal base of the stellate spicules vary in length from spicule to spicule. These two type of spicules are present in different proportions, sometimes those with club-shaped rays being more numerous and in other specimens those with octagonal bases and conical tipped rays predominating. Occasionally some globular spicules occur, but always these are rare. The common cloacal cavity is 3-dimensional, with secondary canals at thoracic level and very extensive posterior abdominal chambers which appear to divide the colony into 2 horizontal layers. In the living colonies, these spaces are kept inflated by pressure of the excurrent water, raising the surface test. ZOOIDS. Zooids are about 0.8mm long. Branchial apertures are transverse slits with dorsal and ventral rounded lips. The atrial aperture is wide, exposing most of the branchial sac directly to the exterior. Tapering columnar epithelial cells project from the anterior part of the thorax. Eight long, oval stigmata are in each row in the branchial sac . An oval lateral organ is opposite the third row of stigmata. A projecting retractor muscle is not present. The gut loop is short and horizontal, bending ventrally from the oesophageal neck. The testis 1s undivided and THE AUSTRALIAN ASCIDIACEA 4 329 FIG. 148. A, B, Lissoclinum timorense (ZMA TU482)— A, zooid; B, larva showing thoracic and abdominal buds of blastozooid, terminal columnar cells on tips of ectodermal ampullae, opaque cells in larval test, and Prachjoren adhering to the test around the posterior end of the larval trunk, C, D, Lissoclinum variabile sp, nov. (QM G308008)— C,D, zooids from lefi and right sides, respectively. Scales: 0.1mm. projects posteriorly back from behind the flexed. distal part of the gut loop. The vas deferens is hooked around the posterior end of the testis follicle, extending up along its dorsal border to the atrial cavity. Embryos ate in specimens from Green I. in August, Lizard I. in June (QM G9913, G12621) and Fijiin July. Larvae are large, the trunk 1.5mm long and the short tail wound about halfway around it. Three large antero-median adhesive organs. have 8 lateral ampullae along each side. The epithelitim along the free anterior end ofeach ampulla is differentiated into columnar, possibly adhesive, cells. An oozooid and 2 blastozooids are about halfway along the trunk, each with 4 rows of stigmata. Prochloron cells form a cap vs) oP) o around the narrow pointed posterior end of the larval trunk and the test in front of this cap appears to be growing back to enclose Prochloron cells in what is probably the developing cloacal cavity. REMARKS.The close relationship and dis- tinguishing features between this species and L. histratum are discussed under that species above. Lissoclinum timorense (Sluiter, 1909) from Indonesia was described from a single specimen (broken into two specimen lots, ZMA TU1274 and ZMA TU482). It is a thin, hard, sheet (like colonies from the Palau Is, see Kott, 1982a) with spicules crowded everywhere except in the superficial layer of test at the level of the branchial siphons, where patches occur only occasionally. Spicules are up to 0.06mm in diameter, some have up to 15 club-shaped blunt-tipped rays, but others have only about 7 polygonal bases in optical transverse section with conical tips of various lengths set in them. The extensive, horizontal posterior abdominal cloacal cavity is crowded with Prochloron. Although Sluiter (1909) referred to a likeness to L. bistratum he did not observe the symbionts which, even in the long-preserved holotype pour out of the cloacal cavity in thick clouds when it is cut. Although (Sluiter, 1909) reported a coiled vas deferens, this was not found on re-examination of the types. Some large embryos with an almost spherical trunk, 1.0mm long, 8 rudimentary ampullae and the tail wound completely around it, are in the holotype. Syntypes of Didemnum voeltzkowi Michaelsen, 1920 from Madagascar (ZMH K1099) are 4 narrow colonies to about 2cm long. They have characteristic zooids, and surface papillae are associated with some (but not all) of the bilobed branchial apertures around the margins of the colony. Spicules are predom- inately club-shaped but some have characteristic polygonal bases with pointed conical tips. The Cloacal cavities are packed with Prochloron. Zooids are small with 7-8 stigmata per row, and lack a retractor muscle. Other colonies (ZMH K1111) from Malagasy assigned to this species by Michaelsen (1920) belong to L. bistratum. Specimens from the Palau Is, questionably assigned to this species by Monniot & Monniot (1996: 176), are said to have spicules ‘not exactly similar to those of either ZL. voeltzkowi or L. bistratum’. These spicules have neither been figured nor described, nevertheless it is possible to assign these specimens to the present species MEMOIRS OF THE QUEENSLAND MUSEUM as spicules of L. bistratum are uniform while those of L. timorense are variable and diverse and the specimens have brown pigment (without red or yellow carotenoids), 8 stigmata per anterior row in the branchial sac and papillae on the surface of the colonies. Projecting columnar cells on anterior parts of the thorax occur also in L. nebulosum and L. variabile and in most Didemnum and Polysyncraton, although their occurrence does not imply a phylogenetic relationship. Some spicules of the present species resemble those of Didemnum digestum and D. uturoa, but the occasional large rays of those 2 species do not occur. The small lobulating colonies that form a mosaic over the Fijian reef flats and that occur at Green I. and Lizard L. are identical in every way to the sheet-like ones, except in their colony size and growth habit. Possibly lobulation is a direct response to crowding. Lissoclinum triangulum (Sluiter, 1909) (Fig. 177A) Diplosomoides triangulum Sluiter, 1909: 86, Lissoclinum triangulum: Kott, 1977: 620; 1998: 89. Echinoclinum triangulum: Kott, 1980: 21. Not Echinoclinum triangulum: Millar, 1975; 241 (< L. taratara). Echinoclinum philippinensis Tokioka, 1967: 93. NEW RECORDS. Queensland (Heron 1., QM GH1345, GH2266; Green [., QM GH430; Lizard I., QM GH112, GH123). PREVIOUSLY RECORDED. Queensland (Heron I. —QM GH12623 Kott, 1977, 1980). Indonesia (Sluiter, 1909). Philippines (USNM 11790-1 Tokioka, 1967). The species is found in cryptic habitats in rubble zones and below low tide levels to 20m around coral reefs. COLONY. Colonies are soft and flat up to 6cm in maximum extent and up to 0.5cm thick. Bladder cells are present throughout the test. Spicules are in a layer beneath the superficial layer of test, and they form a capsule around each zooid. They become sparse, and in smaller specimens are absent, toward the base of the colony. Also in smaller specimens, the capsule of spicules around the zooids is particularly thin. Spicules are flattened with fine needle-like rays of different sizes — small on each side and longer around the edges where they determine the diamond or triangular outline of each spicule by progressively lengthening toward the points. Spicules are up to 0.08mm in greatest dimension. The cloacal cavity is 3-dimensional with deep canals around each clump of zooids. These deep THE AUSTRALIAN ASCIDIACEA 4 331 canals extend into posterior abdominal spaces. The latter are interrupted by connectives joining each clump of zooids to the basal test. Secondary thoracic cloacal cavities penetrate amongst the zooids in each clump. Plant cells are present in the cloacal cavity and embedded in the test. Their identity is not known. ZOOIDS. Zooids are relatively large, about 1.5mm long, despite the abdomen usually being bent up across the posterior end of the thorax. The branchial aperture has 6 distinct pointed lobes. The atrial aperture is wide exposing most of the branchial sac directly to the common cloaca. About 12 long, narrow stigmata are in each row of the branchial sac. A narrow lateral organ is about halfway up the thorax on each side of the endostyle. A retractor muscle is not present. The gut forms a simple loop with the proximal part of the rectum flexed up over the gonads. A straight vas deferens extends from the dorsum of an undivided testis. Larvae have not been recorded from Australian specimens. In discussing L. mereti, Monniot & Monniot (1987:50) described the larvae from the type specimen of the present species as having a trunk 1.2mm long, and 6 pairs of ectodermal ampullae. Blastozooids were not detected. REMARKS. Millar (1975) assigned specimens from Banda, Kei I. and Amboina (L. triangitlum: Millar, 1975) to this species. However, the spicules of Millar’s specimens appear to be more like those of L. taratara with large, thick, separated rays, Further, although the larvae Millar (1975) described, lack blastozooids, they have a trunk only 0.6mm long with 4 pairs of lateral ampullae like L. mereti, which however does have larval blastozooids and spicules different from Millar’s specimens. L. mereti has spicules like the present species and differs from it principally in its larval blastozooids and fewer lateral ampullae. Kott (1980) examined the syntypes of £. Philippinensis Tokioka, 1967 (USNM 11790-1) and assigned them to the present species, as Millar (1975) had suggested — albeit they are not conspecific with the specimens Millar had before him (< L. taratara). Lissoclinum variabile sp. nov. (Figs 2C, 148C,D, 178F) DISTRIBUTION. TYPE LOCALITY. Queensland (Heron I., eastern end of reef, low tide, coll, P. Kott 9.3.93, holotype QM G308008). COLONY. The colony is soft, gelatinous and appears to be black in life owing to the black zooids seen through the transparent test. The colony is very delicate with a huge cloacal cavity. Zooids are in separate branches of the narrow test strands that connect the thin surface and basal layers of test. Spicules are never crowded, but they are evenly distributed throughout the test. They are particularly diverse, and include stellate spicules with up to 17 short conical rays in optical transverse section, and others with as few as 5 longer, more acutely pointed rays in optical transverse section. Spicules with more or less flattened tongue-shaped rays and globular spicules with crowded flat-tipped rays also occur. Spicules are mostly about 0.03mm diameter, but larger ones to 0.09mm diameter are scattered amongst them. ZOOIDS. Zooids are small, to 0.7mm long, although the distal tip of the gut loop is flexed ventrally. Some columnar epithelial cells project from around the base of the branchial siphon. Brownish-black squamous epithelium persists in the body wall over the stomach and the rest of the gut loop. The thorax is long with 4 rows of about 8 rather long rectangular stigmata per row. The large atrial aperture exposes most of the branchial sac directly to the cloacal cavity. Fine muscles are in the transverse vessels, and dorsal pharyngeal muscles continue in the long retractor muscle extending posterior to the abdomen. The divisions of the gut loop (other than the spherical stomach) are inconspicuous. The testis lies behind the flexed distal part of the gut loop. It is divided into 2 follicles and the vas deferens extends anteriorly between them, short vasa efferentia issuing from their distal ends. Two vascular appendages extend from the ventral concave part of the gut loop. They extend away from the zooid in the test connectives and are conspicuous principally because of their terminal ampullae. REMARKS. Black squamous ectoderm surrounding the abdomen 1s conspicuous both in living and preserved zooids, and is clearly seen through the transparent test, as in Diplosoma listerianum. D. listerianum also has a retractor muscle and 2 testis follicles but lacks spicules. The dark squamous epithelium is present over the abdomen in Didemnum albopunctatum and Polysyncraton orbiculum as well as over the whole zooid in Diplosoma spp. and Trididemnum spp. A phylogenetic relationship is not implied. L. ravarava Monniot & Monniot, 1987 from French Polynesia and L. limosum have similar soft colonies, although their spicules are smaller and less diverse than in the present species, they lack the black squamous epithelium in the body wall, their testes are undivided and they lack retractor muscles. L. polvorchis Monniot, 1992, like the present species, has some spicules with flattened rays like those of Polysyncraton pontoniae, but it has more numerous testis follicles, lacks a retractor muscle, lacks the diversity of spicules of the present species and has spicules crowded around the margins of the colony. L. concavum from southern Australia has similar spicules to the present species, differing in having more male follicles (6) and and in lacking black squamous ectoderm. Genus Clitella gen. nov. TYPE SPECIES. Clitella nutricula sp. nov. Zooids are arranged in circular systems of up to about 10 around a central common cloacal cavity and aperture . A layer of small spicules encapsulates the abdomen of some of the zooids. Zooids have 4 rows of stigmata, a wide and sessile atrial aperture exposing most of the branchial sac directly to the cloacal cavity, a strong tapering retractor muscle, stronger longitudinal parietal thoracic muscles than in most other genera of the Didemnidae, especially wide dorsal pharyngeal muscles, a long gut loop divided into duodenum, oval posterior stomach (in the loop of the gut), and the proximal part of the ascending loop distinctly separated from the distal part as a prerectal chamber. The testis is undivided. The proximal part of the vas deferens is much expanded into a large seminal vesicle. Larvae are large and produce numerous premature buds in the larval trunk, resulting in up to 7 whole blastozooids (both thoracic and abdominal buds), each successively producing the next blastozooid in the series. The larval trunk is, accordingly, of unusually great diameter, and is an antero-posteriorly flattened thick disc. The tail, from the centre of the posterior surface, winds around the disc in a median groove that separates a shallow right from a left frontal lobe. Each adhesive organ is a convoluted groove on each frontal lobe. Small larval epidermal vesicles (rather than club- or finger-shaped ampullae) are in rows along each side of the adhesive grooves. Conical adhesive organs in an epidermal cup known in other didemnid genera do not occur. MEMOIRS OF THE QUEENSLAND MUSEUM The cerebral vesicle is in a sac constricted off from the rest of the trunk. Thus, although zooids are similar to some Lissoclinum spp., the genus is distinguished by the small, separate circular cloacal systems, strong thoracic musculature, distinct retractor muscle, undivided testis, vas deferens expanded into a seminal vesicle in its proximal part and unusual disc shaped larva with very numerous blastozooids, highly modified adhesive organs in the form of convoluted grooves and the cerebral vesicle projecting away above the oozooid and constricted off from it. The homology of the adhesive grooves with the separate stalked epidermal cups with central adhesive cones of the adhesive organs of other didemnid genera can be seen if a cross section of the groove is examined. The central ridge appears to be homologous with the adhesive cones of all other genera, while the walls of the concavity appear to be homologous with the epidermal cup surrounding the cones. The adhesive grooves of the present genus appear to be the result of extensive lengthening of both the adhesive cones and their epidermal cups into long convoluted tracts. The adaptive value of such a lengthening may be associated with the flattened disc-shape of the larval trunk, While the 3 point adhesion at the narrow end is adequate for the usual didemnid larvae with an oval trunk, adhesion over a wider area may be more effective when the frontal end of the trunk is more or less flattened and the whole trunk is disc-shaped to accommodate the precocious blastozooid production in this new genus. The budding process also seems to be unusual, in that instead of separate thoracic and abdominal buds being produced always from the oesophagus of the oozooid, each successive blastozooid forms the new blastozooid in the series. The budding process is characteristic of this family, occurring by division across the oesophageal region, leaving the parental thorax with the new abdominal bud and the parental abdomen with the new thoracic bud. The resultant circle of zooids presumably forms the initial system of the colony, its components being in place before settlement and metamorphosis. The atrial apertures are all directed back to the posterior (upper) side of the disc where the common cloaca will be formed as the tail is withdrawn for absorption into the haemocoel of the larval trunk. The best developed blastozooids are those nearest to the oozooid, although in all the gut loop is well-formed and 4 rows of stigmata are present. THE AUSTRALIAN ASCIDIACEA 4 33 A single species, represented only by its holotype, is the basis for the present genus. Its evolutionary distance from Lissoclinum is attested by the prolific precocious budding from successive blastozooids and by its unique larval adhesive organs. The genus name derives from Clitella (f.), a pair of panniers or a pack saddle, reflected in the two frontal lobes of the antero-posteriorly flattened larval trunk. Clitella nutricula sp. nov. (Figs 2B, 149,150) TYPE LOCALITY. South Australia (Sir Joseph Banks Group, Marum I. N. Point, reef, rubble sand and sparse Posidonia 5-8m, coll. K. Gowlett Holmes and N. Holmes 19.1.86, holotype SAM E2678). COLONY. The colony is a soft, gelatinous cushion, with a smooth more or less rounded upper surface, rounded margin and a shallow basal concavity where it was fixed over arounded substrate. It is about 2cm long, lem wide and 0.5em thick. Although soft, the test is resilient and does not tear easily, and zooids are tightly embedded and difficult to remove, It is brownish and translucent, and zooids are a darker brown and show through the test. They are arranged in separate circular systems (about 4mm in diameter) of up to 10 zooids around a simple circular cloacal cavity (at thoracic level) with a central sessile common cloacal aperture. The branchial openings are inconspicuous on the surface and have soft test pulled down into the siphons, which, in these colonies, are also contracted down into the surface. Spicules to 0.04mm diameter are stellate with up to 7 conical rays in optical section, or burr-like with needle- like rays. They form a capsule around the abdomina in some parts of the colony, but are absent completely from other parts. These spicules break up easily if attempts are made to tear the resilient test that contains them. ZOOIDS. Zooids are much contracted in the holotype colony, thoraces being only about 0.7mm long, and the abdomina about Imm. Stalked, spatulate-tipped columnar epithelial cells project from the body wall of both the thorax and abdomen (see Glossary, epidermis; Fig. 2B). The thorax is robust, with a well formed branchial siphon, 6 distinct lobes around the aperture and numerous longitudinal muscles that are deflected around the open atrial aperture which exposes most of the middle part of the branchial sac directly to the cloacal cavity. An atrial lip is not present. Dorsal pharyngeal Wo FIG. 149. Clitella nutricula gen. nov., sp. nov. (SAM E2678); A, upper surface of part of colony zooids visible through translucent test, larvae just beneath surface; B, thorax; C, abdomen, the proximal part of the vas deferens expanded into a seminal vesicle. Scales: A, 1.0mm; B, C, 0.1mm. muscles are wide and a strong retractor muscle projects from the posterior end of the thorax. About 14 stigmata are in each row of the branchial sac, although these could not be counted accurately because of contraction. The gut loop is long and vertical with a relatively long MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 150. Clitella nutricula gen. nov., sp. nov. (SAM E2678); A, larva from anterior end of trunk showing adhesive grooves, oozooids and blastozooids, ectodermal vesicles; B, larval trunk from above showing oozooid and blastozooids on right side, ectodermal vesicles, adhesive grooves, and the groove in the antero-median line where the tail winds around the trunk; C, diagrammatic section through the end of the adhesive groove (homologous with the epidermal cup of standard adhesive organs) with the continuous ridge of adhesive cells (homologous with the adhesive cone of standard adhesive organs) arising from the base of the groove. Scales: A,B, 0.2mm; C, 0.05mm. stomach, duodenum and oval posterior stomach in the pole of the loop. The proximal part of the ascending limb consists of a distinct prerectal chamber that is sharply cut off from the narrower distal part of the rectum. The testis is almost spherical and the vas deferens originates from its posterior end as a narrow tube which curves to the right before expanding into a wide seminal vesicle passing over the testes or slightly to its right as it extends anteriorly to the atrial aperture. The large antero-posteriorly flattened disc-like larval trunk, 2mm in diameter and 1mm thick, has left and right frontal prominences with the convoluted, probably adhesive, groove winding over its surface and small spherical ectodermal vesicles as described above. The 7 whole blastozooids encircle the front of the larval trunk from the oozooid (to the right of the tail) in an anticlockwise direction (frontal view) around the meridian of the disc, in a continuous series with the oozooid. The sensory vesicle projects back and out from the oozooid in a long comma-shaped sac constricted at its base. The oozooid and then each successive blastozoooid produce a thoracic and an abdominal bud, and then divide across the oesophageal region to produce the next blastozooid in the series in the process of oesophageal budding that is characteristic of the Didemnidae. Both oozooid and blastozooids have well-formed adult organs including 4 rows of stigmata and an entire gut loop with its distinct sub-divisions. REMARKS. Lissoclinum spp. with similar distribution of spicules (encasing the abdomina) are in the verrilli, triangulum and punctatum groups, However, the larva has unique adhesive grooves and precocious blastozooids and the colony has simple circular systems of relatively few zooids unusual in the Didemnidae, These characters readily distinguish the species from all others in related Lissoclinum. Zooids are less distinctive although they are more muscular than those of Lissoclinum, in particular the dorsal pharyngeal muscles are wide, whereas in Lissoclinum they are characteristically narrow. THE AUSTRALIAN ASCIDIACEA 4 335 Genus Diplosoma MacDonald, 1859 TYPE SPECIES. Diplosoma rayneri MacDonald, 1859 (< Leptoclinum listerianum Milne Edwards, 1841). The genus is characterised by its relatively large thoraces, each with a wide open atrial aperture exposing most of the branchial sac directly to the cloacal cavity, a straight vas deferens, testis either undivided or consisting of 2 follicles, and the virtual absence of spicules (some minute ones sometimes are present). Larvae, relatively large and yolky usually having a trunk 0.5—1.0mm or more, are unique in always having an oozooid and one to 3 blastozooids usually at the anterior end of the trunk, often projecting from it and associated with the frontal adhesive array — rather than being in the centre of the trunk and posterior to the yolk mass as they usually are in all other didemnid genera. Four rows of stigmata are in the larval pharynx of both oozooid and blastozooids. As larvae mature the trunk divides horizontally isolating the oozooid from the blastozooids and the adhesive organs. Zooids in D. ferrugeum and D. listerianum have large leaf-like branchial lobes that alternate with smaller intermediate ones. D, translucidum and D. velatum have narrow tentacle-like branchial lobes from a short wide base. They never have an atrial tongue. A retractor muscle is present. The cloacal cavity usually is extensive, being either horizontal with spaces at thoracic level and abdomina embedded in the basal test; or 3-dimensional with thoracic and posterior abdominal spaces, the latter traversed by connectives between basal test and the zooid- containing test of the upper half of the colony; or vast horizontal spaces with zooids entirely embedded in connectives between thin surface and basal layers of test. Abdomina usually are bent ventrally and slightly to the right of the posterior end of the thorax. Often a black pigment spot is present in the body wall near the neural ganglion. This spot is made up of irregular pigment particles in the antero-median rim of the atrial aperture, and although close to the neural ganglion (owing to the withdrawal of the rim of the atrial opening) it is not actually associated with it. In many species the ectoderm of the abdomen and sometimes also the thorax is black squamous epithelium, seen as a mosaic of black polygonal cells each with a light-coloured nucleus. This epithelium occurs commonly in Trididemnum (savignii group) but it is also in Didemnum (D. albopunctatum), Polysyncraton (P. orbiculum) and Lissoclinum (L. variabile). Despite this there are few characters shared by Diplosoma and either Trididemnum or Polysyncraton or Didemnum. Diplosoma most closely resembles Lissoclinum in its vast cloacal spaces, large thoraces, large capacious gut, undivided or 2-lobed testis, straight vas deferens, and 4 rows of stigmata in the oozooid. Diplosoma differs from Lissoclinum in lacking spicules and an atrial tongue and the presence of an oozooid and abdominal and thoracic buds of 1-3 larval blastozooids (often one, or occasionally 2 in Lissoclinum and Polysyncraton, and sometimes one in Didenimunt) at the anterior end of the larval trunk (anterior to the yolk mass). The replication rate of certain species in this genus, and consequently their growth rate, is high, often 4 or more generations of replicates being formed simultaneously in the oesophageal region (Kott, 1980). Consequently the 2-dimensional colony growth (a property of Didemnidae generally) may proceed at a greater rate than in other genera, resulting in very thin colonies spread over vast areas (D. simile, D. listerianum). Colony replication probably also occurs in some species (e.g. D. virens: Ryland et al., 1984), reflecting an additional aspect of the growth process. Obligate symbioses of certain tropical Diplosoma spp. with the prokaryotic Prochloron occur, Although their biomass is considerable, the number of species involved — D. multi- papillatum Kott, 1980, D. simile (Sluiter, 1909), D. virens (Hartmeyer, 1909) — is not as great as in Trididemnum or Lissoclinum. D. simile and (to a lesser extent) D. virens are conspicuous in coral reef communities and may cover greater areas in the tropics than any other species in any genus. The species of Diplosoma in obligate symbiosis with Prochloron always have the plant cells in the common cloacal cavity rather than in the test. All these species have a distinctive organ (the rastrum) by which the algal cells are transferred from one generation of the host species to the next (Kott, 1980; 1981; 1982a,b). The larval test over the rastrum is broken up into a brush of hairs which gather and enmesh plant cells as the larva, having been incubated in the basal test of the colony, breaks into the common cloacal cavity through the layer of plant cells that line it. Although in other genera, parts of the larval test over the trunk (Lissoclinum spp. and Didemnum spp.) and even the whole test (Trididemnum spp.), incorporate symbiotic cells before release from the parent colony, it is only in Diplosoma that this special organ has evolved for the purpose. Monniot (1993) referred to a concavity beneath the larval tail of Polysyncraton multipapillae as a rastrum. This is an incorrect use ot this term (see Glossary). Diplosoma is the least diverse genus known in this family. This may result partly from difficulties in distinguishing species from one another owing to an impressive uniformity in the appearance of both colony and zooids after fixation and preservation. This post-mortem resemblance relates to most known species (with the exception of the Prochloron symbioses). Rowe (1966) synonymised D. listerianum Milne Edwards, 1841, well known in European waters, with D. macdonaldi (Herdman, 1886) from the tropical Atlantic (Brazil) and the western Pacific (Gottschaldt, 1898; Van Name, 1918), and D. mitsukurii (Oka, 1892) from Japan. Although these specimens look very similar in preservative, their appearance in life may be different and additional information on aspects of their morphology and biology could reflect their genetic distinctness. At present, however, D. listerianum appears to be a truly cosmopolitan species being recorded in tropical and temperate waters of all oceans. The few species in this genus represented in Australian waters are relatively common, The tropical Prochloron/Diplosoma symbioses are common and well documented and, although less well known, there also are several non-symbiotic tropical and temperate species, both cosmopolitan and indigenous. KEY TO THE SPECIES OF DIPLOSOMA RECORDED FROM AUSTRALIA 1, Prochloronincommon cloacal cavity, .... 2... 2 Prochloron notin common cloacal cavity 2. Retractor muscle free from posterior end ofthorax .. . whee) ald try be wtebets Loy pieheghe sod F D. simile Retractor muscle free from halfway down oesophageal iC See ee

30h (2 wedarnn), Diplosomer treaisticidian: Uartmever, 1919) 125; Kou, (98s 85 (part, nor specimens trom Bass Strait or SW coast, Not Dinlosama transinerduim Kot, 197352 (0; (97 ti 72 <1 vuletunt), Dinlosome inflatum Moaniot, 1994: 5, NEW RECORDS. Western Australia (Cape Ruthieres, QM 6302946: NNE Dampier Archipelagu, WAM 5.99) Queensland (Hervey Bay, QM G9440, C9443, GHIDAD, Capricorn Group, QM GH759, GH2259, G30) 44, G308349. Lizard 1,QM G301542, C302027, CI0205% 1 17°03°S 146°07.8°F, OM GH2345), PREVIOUSLY RECORDED. Western Australia (Cape Jaubert —Tlartmever, 19179), Indonesia (Sluiter, 1909). New Caledonia (Monniot, 1994), Recorded colonies are from low tide to 160) (Harter, 1919), COLONY, Colonies are fleshy and firm sheets, and the test 1s tough, Hbrous and does not tear readily. In life the test is clear (v translyent and rufus" with flesh® to orange or red-brown zoids showing through, In preservative, al first (he lest is cloudy and the zooids pink-bcige en pinkish-brown with a brown gut loop ani embryos, After long-term preservation the colonies are light grey, with white zoods showing (through the translucent test. A yellowish-white ning of granules surrounds each of the relatively humerous large sessile common cloacal apertures was observed in one colony (WAM 5.93). Both surface and basal layers of test are thin, Zooids are held at the surtace by their separate branchial siphans. The whole zooid sometimes is separated from others but the terminal branches of test connectives are short, keeping zooids together and offen the abdormina are not separated from one another, the abdomina of each group of 2-6 zouids usually being clumped together in common test and attached to the hasal test by i single connecting strand. The primary cloacal cavities extend around and posterior to each MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 154. Diplosoma translucidum (A, WAM 5.93; B, QM G308349; C, QM G301542)—A, surface of colony; B, zooid; C, larva showing oozooid, blastozooid and columnar epithelium on tips of club-shaped ectodermal ampullae. Scales: A, 1.0mm; B,C, 0.1mm. clump of zooids, interrupted only by the vertical connective between each zooid clump and the basal test. Secondary cloacal canals penetrate each clump of zooids at thoracic level, Colonies are thicker in life than in preservative owing to the inflated common cloacal cavity. Embryos are in the basal test. The large common cloacal apertures are randomly placed over junctions of deep primary canals that separate each clump of zooids. Zooids are difficult to remove from the tough fibrous test of the preserved colonies. ZOOIDS. Zooids are relatively small, the thorax being only about 0.5mm long. The oesophageal neck is relatively long and the distal half of the abdomen, from the level of the stomach, bends at right angles to the longitudinal axis of the zooids to lie horizontally. Dark squamous epithelium is on the abdomen but is not always evident. The branchial siphon is cylindrical, and the aperture is fringed with 6 long finger-like lobes. When contracted the rim of the aperture between these lobes projects out like an accessory lobe. A moderately long, narrow retractor muscle projects from the posterior end of the thorax. The atrial aperture is wide, exposing most of the branchial sac directly to the cloacal cavity. Ten stigmata are in the anterior row in the branchial sac, reducing to 8 in the posterior row. The stomach lies more or less obliquely where the abdomen bends horizontally, and the duodenum, large posterior stomach and the proximal part of the rectum form the horizontal part of the gut loop. A constriction halfway up the rectum was not observed, nor were gastric vesicles seen around the gut. The testis, underneath the horizontal part of the gut loop, consists of 2 follicles side by side. Their short vasa efferentia, one from the inner margin of each follicle, near its THE AUSTRALIAN ASCIDIACEA 4 345 postero-ventral border, join to form the vas deferens which curves around between the follicles, extends straight anteriorly between oesophagus and rectum, and opens near the anus. The ovum is dorsal to the testis, but moves down the test connective into the basal test at an early stage, presumably following fertilisation. The proximal end of the vas deferens sometimes is swollen into a large seminal vesicle. Embryos are in the basal test of colonies taken off Cairns (QM GH2345) in January, Lizard I. (QM G301542, G302027, G302030-1) in June, off the northern tip of Western Australia (QM G302946) in August, the Capricorn Group (QM G308349, GH759) in November and Hervey Bay (QM G9440) in November. Larvae are large, the trunk 0.8mm long, with a relatively long narrow tail wound three quarters of the way around it. The anterior three quarters of the trunk is occupied by a large oozooid and one or 2 blastozooids of more or less equal size (each with 4 well developed rows of stigmata), 3 median adhesive organs (with long narrow flexible stalks and deep tulip-shaped terminal cups and axillary cones), and 2 or 3 ectodermal ampullae per side (each with columnar ectoderm on the expanded, almost globular tip). The cerebral vesicle (with ocellus and otolith) protrudes dorsally from the oozooid. Well advanced larvae prior to liberation are found in pouches projecting up into the common cloacal cavity from the basal test (QM G302946), Presumably they are liberated into the cloacal cavity by rupture of these pouches. REMARKS. The species is characterised by its tough test, relatively small zooids, abdomen posterior to the thorax (not folded up against it), tightly clumped zooids — each clump with a single, unbranched test connective crossing the cloacal cavity to the basal test, narrow pointed branchial lobes, and large larvae with well advanced oozooid and blastozooids. The latter resemble D. ata Monniot & Monniot, 1987, which has a retractor muscle but only one testis follicle. The New Caledonian specimens (as D. inflatum) of the present species differ from the newly recorded ones in having | 2 (rather than 10) stigmata in the anterior row — although there is some inconsistency in the numbers shown (Monniot, 1994, fig. 2A,C), and a shorter Jarval tail. These differences probably are not of sufficient significance to indicate a separate species, especially in view of compelling similarities such as the general form of larvae, zooids, colony organisation, and fibrous test. The present species lacks the black pigment spot near the dorsal tubercle found in D. versicolor Monniot, 1994. It is distinguished from D. listerianum and D. ferrugeum (which have similar larvae) by its more restricted cloacal cavity, unbranched connectives between the large clumps of zooids and basal test and its tough fibrous test. Embryos of the present species (like those of D. listerianum), develop in the basal test rather than in the test connective attached to the floor of the cloacal cavity as in D. ferrugeum. Colonies of the temperate species, D. velatum (>D. translucidum: Kott, 1962, 1975, 1976), have the same narrow finger-like branchial lobes, number of stigmata per row, 2 male follicles, retractor muscle originating from the posterior end of the thorax, and they lack a pigment spot associated with the dorsal tubercle. The test of D. velatum is much softer than the present species, however, and its test connectives are branched as in D. listerianum and D. ferrugeum. The colonies described by Sluiter (1909) and Hartmeyer (1919), with zooids showing as white flecks through tough, light grey/translucent test are not significantly different from the Australian and New Caledonian specimens. Sluiter specifically mentions the 6 lobes of long branchial siphons. Hartmeyer referred to the tough test, and both observed the ectodermal vessels and their terminal ampullae in the basal test. Rowe (1966) suggested that Leptoclinum perspicuum (Giard, 1872) (originally Astellium) was not considered congeneric with L. pers- picuum Sluiter, 1909, and thus Sluiter’s name is not a homonym and is still the valid name for the present species. However, Hartmeyer (1909) removed L. perspicuum (Giard, 1872) to Didemnum after Slutter (1909) had erected L. perspicuum Sluiter, 1909. Hartmeyer (1909) correctly provided a replacement name (LZ. translucidum) for Sluiter’s species. Diplosoma velatum sp. nov. (Fig. 155; Pl. 21F,G) Leptoclinum translucidum Kott, 1962: 306. Diplosoma translucidum: Kott, 1975: 10; 1976: 72; 1998: 85 (part, specimens from Bass Strait and SW Australia). TYPE LOCALITY. South Australian (York Peninsula, Point Turton jetty piles on Posidonia seagrass 3-4m, coll. K.L. Gowlett Holmes, W. Zeidler. 16.3.94, holotype SAM E2612; Edithburgh, sand flat with sea grass, 5m, coll. AIMS Bioactivity Group 9.2.89, paratype QM G302909). MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 155. Diplosoma velatum sp. nov. (A, WAM 1155.88; B, SAM E2612; C, SAM E2687) — A, surface of colony; B, zooid; C, larva. Scales: A, 1.0mm; B, C, 0.1mm. FURTHER RECORDS. Western Australia (Esperance, WAM 1155.88). South Australia (Tipara Reef, QM GH3707, GH3753; Eyre Peninsula, SAM E2687; Cathedral Rock, SAM E2832; Kangaroo I, QM G302911, SAM E2587). PREVIOUSLY RECORDED. Western Australia (Oyster Harbour — Kott, 1962). South Australia (Investigator Strait — Kott, 1975). Victoria (Western Port — Kott, 1976). COLONY. Colonies are extensive fleshy sheets or regular, flat to rounded or oval plates or lobes, often found encrusting sea-grass. The test is soft and even slimy, but the colonies are turgid, more or less holding their shape in preservative. In preservative they are up to 5mm thick and may be even thicker in life when the common cloacal cavities are fully inflated. Zooids are in crowded groups or double rows of up to 20 divided into sub-groups of 5—8 zooids. Groups of zooids are visible through the translucent test as patches of white flecks separated from one another by narrow zooid-free strips over the common cloacal canals. Abdomina of zooids in each of the sub-groups are sometimes embedded together in a branch of the single flat test connective that anchors the whole group to the basal or central plate of test, although the thoraces are separate from one another, attached to the surface test by their branchial apertures and sheathed ventrally by separate terminal branches of the test connectives. In other colonies both the abdomina and thoraces are separate, each in a terminal branch of the test connective. The common cloacal cavity is vast, extending the full depth of the zooids around each sub-group, and even more deeply around each major grouping of zooids where the cavity extends behind the zooids to surround the basal common test connectives. Common cloacal apertures are circular when open and fairly regularly spaced about |cm apart. The vascular appendages from each zooid extend deep into the test connectives where their elongate terminal ampullae are evident. The test is transparent, almost glassy but slightly pink and cloudy in preservative. There are no spicules. Living colonies are orange. ZOOIDS. Zooids are of moderate size, to 1.5mm long with a large thorax, long oesophageal neck, THE AUSTRALIAN ASCIDIACEA 4 347 and shorter abdomen. Branchial apertures are small on short siphons with a delicate sphincter muscle and 6 narrow, pointed lobes. When the apertures are contracted the rim of the opening between the narrow lobes is thrown up into a small projection. Ten stigmata are in the anterior row in the branchial sac. The gut loop is horizontal, behind the branchial sac and there are 2 male follicles with a straight vas deferens, its proximal end in the groove between them. A long, narrow retractor muscle projects from the posterior end of the thorax. Zooids are white in preservative and do not have dark squamous epithelium over either thorax or abdomen. Embryos are present in specimens from Oyster Harbour (Albany) collected in December, Kangaroo I. (QM G302911) in January, the Eyre Peninsula (SAM E2687) in February and Tipara Reef (QM GH3707, GH3753) in May. The larval trunk is large (1.0-1.2mm long) with blastozooids and 3 finger-like ectodermal ampullae each side of the 3 urn-shaped, antero-median adhesive organs (Kott, 1962). The ocellus is in a small papilla-like protrusion from the oozooid about halfway along the dorsum, but the otolith hes beneath it obscured by the small opaque inclusions in the larval test. The tail winds halfway around the trunk, REMARKS. Kott (1962) assigned specimens of this species (from Albany) to the tropical D. translucidum, invoking the large common cloacal cavity as a character of the latter species. Although such a cloacal cavity occurs in D. listerianum, D. ferrugeum and certain Lissoclinum spp., the common cloacal cavity of D. translucidum is more restricted and the basal test connectives are unbranched. The test of D. translucidum is much tougher, and the colonies have a blue-grey shimmer (Sluiter, 1909; Hartmeyer, 1919) rather than the faint pink colour of the preserved colonies of the present species. Larvae of the present species are larger than those of D. translucidum but otherwise are similar. The branchial lobes are narrower and tentacular unlike the broad leaf-like ones of D. listerianum and D. ferrugeum. Diplosoma virens (Hartmeyer, 1909) (Fig. 156; Pl. 21H) Diplosoma viride Herdman, 1906: 341. Leptoclinum virens Hartmeyer, 1909; 145-6, Tokioka, 1942: 500; 1967: 68. Kott, 1966: 291, Diplosoma virens: Hastings, 1931: 102, Newcomb & Pugh, 1975: 533. Thinh & Griffiths, 1977: 673. Thinh, 1978: 617. Kott, 1980: 22, figs 27-30; 1981: 193; 1982a: 114; 1998: 85. Monniot, 1994; 10. Not Diplosoma virens: Eldredge, 1967: 228. Kott, 1977: 620. Thome, Newcomb & Osmond, 1977: 575 (< Diplosoma simile), Not Leptoclinum viride Herdman, 1906: 340 (< Didemnum viride). Leptoclinum simile Sluiter, 1909: 77 (part). Leptoclinum varium Sluiter, 1909: 80. Leptoclinum calificiforme Sluiter, 1909: 82. Van Name, 1918: 160. Diplosoma pavonia Monniot & Monniot, 1987: 60. ?Diplosoma matie Monniot & Monniot, 1987: 58, NEW RECORDS. Western Australia (Shark Bay, WAM 1057.83). Queensland (Capricorn Group, QM G301902, G302448; Swain Reefs, QM G308405, G308416 Magnetic L; Lizard I., QM G302348), Northern Territory (Cape Don). Western Pacific (West Caroline I., QM GH816). PREVIOUSLY RECORDED. Queensland (QM G9937 Heron I,, QM G12484 Green I., Lizard 1., Sue 1. — Kott, 1977, 1980 1982a; Low Is — Hastings 1931). Northern Territory (Darwin — Kott, 1980). Western Pacific (Caroline Is, Palau Is, Kiribati, Marshall Is, Philippines — Van Name 1918, Tokioka, 1942 1967, Kott, 1980 1982a; Solomon Is— Monniot, 1994; Fiji - QM G12485 Kott, 1980, 1981: French Polynesia —Monniot & Monniot, 1987). Indonesia (Leptoclinum varium ZMA TU597, TU599.6, TU599.8; L. calificifome ZMA TUS573; L. simile ZMATUS91.2 Sluiter, 1909). Indian Ocean (Sri Lanka — Herdman, 1906). The greatest depth recorded for the species is off Amboina at 40m (Sluiter, 1909: ZMA TU599.6). It is known to occur on the open reef flat on the side of tidal pools in Fiji (Kott, 1981) and along the reef edge and in surge channnels around the base of stands of living coral to 5m. COLONY. Colonies are small circular to oval cushions from 0.5—2cm long and 2—S5mm thick. Smaller colonies are almost spherical but larger ones are almost flat on the upper surface, with a depression in the centre from which the common cloacal aperture protrudes on a conical or cylindrical chimney which often is bent in the direction of the prevailing current. The upper rim of the opening may be incised to expose the excurrent flow from the colony to entrainment by the current flowing over it (Kott, 1989). Colonies are known to lobulate and to move and space themselves evenly but close to one another (Ryland et al., 1984). Zooids are around the outside of the central cavity where they are embedded in the relatively tough, firm test that is penetrated by narrow cloacal canals at thoracic level. Primary cloacal spaces are post-abdominal and connect with the central cavity beneath the cloacal aperture. In the vicinity of the zooids, colonies are divided into 4 layers of more or less equal thickness viz. the surface layer of test (including the superficial bladder cell layer) in which the anterior parts of the thoraces are embedded, the zooid layer traversed by a network of narrow canals, the posterior abdominal cloacal MEMOIRS OF THE QUEENSLAND MUSEUM anlea FIG. 156. Diplosoma virens (after Kott 1980:A—C, E-G, QM G12484; D, QM G12485; H, QM G9937) — A-C, colonies from above; D, lateral view showing terminal ampullae of test vessels, protuberant common cloacal apertures and dark green around zooids where common cloacal cavities accommodate symbionts; E, semi-diagrammatic vertical section through colony; F, zooid in vegetative phase; G, thorax; H, larva with developing rastrum above base of tail. Scales: A-D, 1.0mm; E, 0.5mm; F—H, 0.2mm. cavity transversed by strands of test connecting zooid layer to the basal test, and the layer of basal test. The species is in obligate symbiosis with the prokaryote Prochloron, which lines the walls of the cloacal cavities and canals. In life the colonies are paler green in the centre and in the vicinity of the zooids and brighter green around the periphery of the colony where Prochloron lining the thoracic as well as the posterior abdominal canals is most abundant. In preservative, colonies are yellowish mustard- green, grey or brownish-yellow. Usually they are opaque owing to the Prochloron trapped in the complex three-dimensional network of cloacal spaces in the tough fibrous test. Long stolonic vessels from the abdominal region of zooids extend through the test connectives into the basal test, and out around the periphery of the colony, where their terminal ampullae can be seen. ZOOIDS. Zooids are difficult to remove from their tough test sheaths. They are small, about THE AUSTRALIAN ASCIDIACEA 4 1.0mm long, the thorax and abdomen of about equal length. In preservative they are whitish, with clear yellow stomach and glandular parts of the intestine. Often some brown squamous epithelium can be seen on the abdominal body wall although this fades in preservative. The branchial siphon is narrow with a pronounced sphincter muscle. A long, fine retractor muscle is free from about halfway down a long oesophageal neck. The atrial aperture is wide exposing most of the branchial sac directly to the cloacal chamber. Five or 6 rounded to oval or elliptical stigmata lined by flat epithelial cells are in each of the 4 rows. Budding from the oesophageal neck produces 2 sets of buds at any one time and contributes to rapid growth rate of the colonies, and probably their frequent lobulation. The abdomen is bent up at right angles to the long axis of the thorax and oesophageal neck. The post pyloric part of the gut is divided into cylindrical duodenum, posterior stomach, and long rectum constricted halfway up the ascending limb where it is surrounded by tubules of the gastro-intestinal gland. The 2 follicles of the testis are beneath the ventrally flexed part of the gut loop with the proximal part of the vas deferens hooked around between them. Embryos are found in the basal test of colonies collected in October (from Darwin), March (from Heron I.) and June (from Lizard I.). The larval trunk is up to 1.5mm long, with the tail wound about halfway around it. A rastrum develops above the point of insertion of the tail. Two to 4 pairs of ectodermal ampullae are on each side of the usual 3 median adhesive organs. Larvae of specimens from Lizard I. have 4-8 adhesive organs. One blastozooid is at the anterior end of the trunk. Mature larvae have a deep division separating the oozooid from blastozooid and adhesive array. REMARKS. Although colony size and number of larval lateral ampullae and adhesive organs is variable, the species has characteristic tough fibrous cushion-like green colonies, cloacal systems (with a network of narrow canals in the upper half of the colony, and extensive posterior abdominal cavities crossed by test connectives from the upper zooid-containing layer), a retractor muscle from at least halfway down the oesophageal neck, and a large larval trunk. Diplosoma pavonia Monniot & Monniot, 1987 with 7 (rather than 3) larval adhesive organs, is identical with the present species. It appears, therefore, that more than one population has more than 3 and up to 8 adhesive organs (see also Lizard I. populations of the present species: Kott, 1982a). This phenomenom probably reflects some, but not complete, isolation. Monniot (1994) suggested that the Solomon Is populations (D. pavonia) are distinguished from D. virens by their biochemistry — being more acid. This is unlikely. The pH (down to 2) of didemnid colonies is generated by lysis of bladder cells (Parry, 1984b). It is unlikely that one species can be said to be more acid than the other— even ifin an unbuffered medium — as the amount of acid generated 1s a result of the number of cells that are lysed and its dilution. Differences in the larvae are also invoked to justify the erection of D. pavonia as distinct from the present species. However, neither oozooid nor blastozooid are well developed and the rastrum does not appear to have begun its development in larvae examined from the Solomon Is. Other characters are within the range of D. virens. D. matie Monniot & Monniot, 1987, from French Polynesia, is a thin investing colony with a large posterior abdominal cloacal cavity traversed by test connectives between the surface zooid-bearing layer and the base of the colony as in D. virens. Zooids, with 2 male follicles and the retractor projecting from at least halfway down the long oesophageal neck, also are like the zooids of D. virens. Monniot & Monniot (1987) report it to have symbiotic algae cells (? Prochloron), but do not record their location — probably in the cloacal cavity. The colour, which Monniot & Monniot (1987) invoked to distinguish D. matie from both D. pavonia and D. simile, does not provide a reliable distinction. Nevertheless, it does have real distinctions from D. simile and it is D. virens, and not D. simile, which is most closely related to D. matie. D. simile is distinguished from both D. matie and D. virens by its smaller larval trunk, the retractor muscle protruding from the posterior end of the thorax rather than from the middle to base of the oesophagus and the extensive thoracic rather than posterior abdominal cloacal cavity. The larva (Monniot & Monniot, 1987, fig. 30G) of D. matie is not well developed, the rastrum is rudimentary and neither oozooid nor blastozooid are well formed. However, other larval organs are developed. It has a large trunk (0.85mm long), 5 —12 adhesive organs and 5 or 6 pairs of ectodermal ampullae. The greater number of ectodermal ampullae provide the only real distinction from D. virens, although in view of the variations in D. virens larvae, this distinction is oP) in So not very conclusive. D. virens has a larval trunk of 1-1.5mm, a variable number of adhesive organs, but only 2-4 pairs of ectodermal ampullae (Philippines: Kott, 1982a). 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Bijdragen tot der Dierkunde 23: 23-32. 1930. The ascidians of Porto Rico and the Virgin Islands. Scientific Survey of Porto Rico and the Virgin Islands 10(4): 403-512. New York Academy of Sciences: New York. 1945. The North and South American ascidians. Bulletin of the American Museum of Natural History 84: 1-476. VASSEUR, P. 1969. Deuxiéme contribution a |’étude des ascides de Madagascar région de Tuléar. Bulletin du Muséum National d’Histoire Naturelle sér. 2 40(5): 912-933. 1970. Contribution a l’étude des ascidies de Madagascar (Région de Tuléar) III. La faune ascidiologique des herbiers de phanérogames marines. Records Travail Station Marine d’Endoume Fasc. hors. série suppl. 10:209-221. VERRILL, A.E. 1871. Descriptions of some imperfectly known and new ascidians from New England. American Journal of Science (3) 1: 54-58, 93-100, 211-212, 288-294, 443-446. THE AUSTRALIAN ASCIDIACEA 4 357 _— nat r FIG. 157. A, Atriolum robustum (QM G305675); B, A. Lilium (QM GH2385); C, A. tubiporum (QM G302885); D, A, bucinum (QM G304670); E,F, A. marinense (QM G301616) showing hollow spicule; G, A. eversum (WAM 366.80); H, Leptoclinides comitus (SAM E2614); I, L. volvus (SAM E1034). G ~~ 358 MEMOIRS OF THE QUEENSLAND MUSEUM G it he" \ 2, a i a im ! FIG. 158. A, Leptoclinides carduus (QM G308154); B, LZ. rufus (QM G301757); C, L. confirmatus (SAM E2619); D, L. wmbrosus (QM G308429); E, L. erinaceus (WAM 128.93): F, L. magnistellus (AM Y 1481): G, L. albamaculatus (QM G308291); H, L. cuspidatus (ZMA TU440.2); I, £. cavernosus (QM G308247). THE AUSTRALIAN ASCIDIACEA 4 359 ae a ew r= wa FIG, 159, A, Leptoclinides imperfectus (QM G302883); B, L. variegatus (SAM E2697); C, L. coelenteratis (AM Y 1343); D, L. longicollis (QM G300898); E, L. brandi (QM G308104); F, L. aciculus (QM G303827); G, L. maculatus (SAM E2659); H, L. exiguus (MV F68745); [. L. placidus (QM GH372). 360 MEMOIRS OF THE QUEENSLAND MUSEUM 1 = ‘ ; : FIG. 160. A, Leptoelinides constellatus (QM GH5420); B, L. seminudus (SAM E2671); C, L£. rigidus (QM GH5371); D, L. compactus (SAM E2635): E, L. sulawesi (QM G308493); F, ZL. lissus (AM G13449): G. L. caelestis (WAM 794.88); H, L. eehinus (QM GH2121): 1, L. levitatus (QM G308700). THE AUSTRALIAN ASCIDIACEA 4 36] FIG. 161, A, Leptoclinides dubius (QM G308239); B, L. durus (QM G3023507); C. L. multilobatus (QM GH1317); D, L. kingi (QM GH5369); E, Polysyncraton flammeum (QM G308461); F, P. discoides (SAM £2623); G.H, P. circulum (QM G308191 showing hollow spicules); I, P. scorteum (SAM E2629). 362 MEMOIRS OF THE QUEENSLAND MUSEUM i a . ° ie H FIG. 162. A. Polysyneraton pulchrum (WAM 137.93); B, P. meandratum (QM G308217); C, P. pureu (QM G308231); D, P. dentatum (SAM E2677); E, P. dromide (QM G301568); F, P. orbiculum (AM Y 1484); G, P. rugasum (QM G305554); H, P. pontuniae (QM G308019); 1, P. magnetae (QM G301538). THE AUSTRALIAN ASCIDIACEA 4 363 FIG. 163. A, Polysyneraton robustum (AM Y2312); B, P. palliolum (QM G300988); C, P. regulum (QM G308474); D, P. multiforme (QM G304641); E, P. arafurensis (WAM 108.93); F, P. echinatum (QM G300993); G, P. glaucum (QM G305628); H, P. pseucdorugosum (QM G308347); I, P. ledix (QM GH5751). 364 MEMOIRS OF THE QUEENSLAND MUSEUM Gi ge H i > J . het FIG. 164. A, Polysyncraton oceanium (QM G308203); B, P. scobinum (QM G308332); C, P. otuetue (QM G308378); D, P. infundibulum (SAM E2610); E, P. papyrus (AM Y 1520); F, P. jugosum (AM G12205); G, P. tegetum (SAM E2698); H, P. millepore (QM G302945); I, P. tasmanense (AM Y1541). THE AUSTRALIAN ASCIDIACEA 4 365 FIG. 165. A, Polysyvncraton rubitapum (QM GH1330); B, P. sideris (AM Y1487); C, P. rica (QM GH5426): D, P. tenuicutis (WAM 390.75). E,F, Didemnum uturoa (QM G301956, G308287); G, D. precocinum (WAM 521.92); H, D. albopunctatum (QM G308031): 1, D. oblitum (QM G308380). 366 MEMOIRS OF THE QUEENSLAND MUSEUM : | ; a FIG. 166. A, Didemnum fragile (QM G308401); B, D. flavoviride (QM GH3477); C, D. molle (QM G308534); D, D. hiopaa (QM G308308); E, D. parancium (QM GH5353); F, D. arancium (QM G308218); G, D. chartaceum (QM G308266); H, D. levitas (QM G308224); I, D. multispirale (QM G302920). THE AUSTRALIAN ASCIDIACEA 4 367 E2653); D, D. jucundum (SAM E2693); E, D. tabulatum (ZMA TU480.3):; F, D, astrum (QM G308112): G, D. jedanense (QM G308491); H, D. monile (SAM E2683); 1, D. theca (WAM 121.93). 368 MEMOIRS OF THE QUEENSLAND MUSEUM G302908); D, D. moseleyi (BMNH 1887.2.4.404 holotype); E, D. inveteratum (QM G302922); F, D. bi- sectatum (QM G302599); G, D. bicolor (QM GH 2410); H, D. macrosiphonium (SAM E2658); I, D. guttatum (QM G302876). THE AUSTRALIAN ASCIDIACEA 4 369 G ai’ 6 H ae FIG. 169. A, Didemnum vahatuio (QM G305373); B, D. elongatum (WAM 79.89); C, D. pellucidum (SAM E2696); D, D. vulgare (SAM E2855); E, D. spadix (SAM E2694); F, D. linatum (WAM 40.89); G, D. lisso- elinum (SAM E2665); H, D. fragum (AM Y1519); 1, D, patulum (MV F70207). 370 MEMOIRS OF THE QUEENSLAND MUSEUM ; i ’ es Ws ce . 7 oe Tle FIG. 170. A, Didemnum caesium (QM G308290); B, D. sucosum (AM U182); C.D. incanum (AM 25134): D, D. membranaceum (QM G308532); E,.D. complexum (AM Y820); F, D. perplexum (QM G302960); G, D, etiolum (QM G301528); H, D. evgnuus (WAM 362.92): 1, D. pecten (QM 300929). THE AUSTRALIAN ASCIDIACEA 4 371 FIG, 171. A, Didemnum fuscum { (QM G302881); E, D. spongioide (QM G303640); F, D, granulatum (QM GH5379); G, D. stragulum (WAM 610.89); H, D. delectum (SAM E2674); I, D. verdantum (QM GH5358). 372 MEMOIRS OF THE QUEENSLAND MUSEUM FIG, 172. A, Didemnum fucatum (ZMA TU448); B, D. roberti (WAM 524.92); C, D. microthoracium (SAM £2656); D, D. herba (QM G308641); E, D. grande (WAM 42.82); F, D. crescente (MV F68801); G, D. viride (QM G305798); H, D. clavum (WAM 103.93); I, D. via (QM GH808), THE AUSTRALIAN ASCIDIACEA 4 373 ‘ Rat nika™s FIG. 173. A, Didemnum sordidum (QM GH1836); B, D. scopi (QM G308219); C, D. eueulliferum (QM G308190); DE, Trididemnum miniatum (ZMA TU441.2, QM G9927—scale 0.00S5mm); F, 7. spumosum (SAM E2616); G, T. crystallinum (QM G302608 — scale 0.05mm); H, 7° clinides (QM G301600); 1, 7. areolatum (QM G308426). 374 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 174. A, Trididemnum paracyclops (QM G12628); B,C, T. dispersum (ZMA TU443.1, QM G301780); D, T. cyclops (QM G308152); E, T. nubilum (QM GH150); F, T. nobile (QM GH2371); G, T. amiculum (AM Z1681); H, 7. tomarahi (QM G308327); |, T. vermiforme (SAM E2602). THE AUSTRALIAN ASCIDIACEA 4 375 768.88); DE, 7. sibogae (ZMA TU1271, QM G303768); F, 7. caelatum (SAM E2670); G, T. paraclinides (WAM617.89); H, T. cristatum (AM Y2321). 1, Lissoclinum punctatum (QM GH35290). 376 MEMOIRS OF THE QUEENSLAND MUSEUM FIG. 176. A, Lissoclinum spongium (QM GH4372); B,C, L. roseum (QM G302506, G302553); D, L. badium (QM G302989); E, L. ostrearium (WAM 199.91); F, L. conchylium (QM G308321); G, L. reginum (QM G308077); H, L. durabile (MV F70229); 1, L. levitum (QM GH2420). THE AUSTRALIAN ASCIDIACEA 4 377 = = S = i 4 FIG. 177. A, Lissoclinum triangulum (QM G12623 — scale 0.05mm); B, L. calycis (QM G308339); C, L. caliginosum (QM G308271); D, L. meiculatum (QM G302236); E, L. nebulosum (QM G301576); F. L. limosum (OM G302330); G, L. taratara (QM GH335); H, L. sente (QM GH59); I, L. tasmanense (QM GH1288). 378 MEMOIRS OF THE QUEENSLAND MUSEUM Gi c : a a Sy) H oe FIG. 178. A, Lissoclinum bistratum (QM G308659); B, L. patella (QM G305714); C-E, L. timorense (ZMA TU1274—C,D; QM GH158— E); F, L. variabile (QM G308008); G, L. concavum (SAM E2691); H, Diplosoma jferrugeum, morula bodies in the test. THE AUSTRALIAN ASCIDIACEA 4 379 G + , - j. Ss : 4 ed PLATE 1. A, Atriolum bucinum (Houtman’s Abrolhos W.A., QM G304670); B, A. Jilium (Flinders I. S.A., QM GH2385); C, A. marinense (Marion Reef Coral Sea, QM G301616); D, A. robustum (Swain Reefs GBR, QM G305675); E, A. tubiporum (Fault Line 20m King George Sound W.A.). F, Leptoclinides albamaculatus (Heron I. GBR, QM G308274); G, L. brandi (Heron I. GBR, QM G308194); H, ZL. cavernosus (Exmouth Gulf W.A., QM G302942). 380 MEMOIRS OF THE QUEENSLAND MUSEUM Cae 4 oS es id PLATE 2. A, Leptoclinides coelenteratus (Rottnest I. W.A.); B, L. compactus (Peforated I. S.A., QM G301589); C, L. constellatus (Haselwood I. S.A., QM G302924); D, L. cuspidatus (N of Barrow I. W.A., QM G300956); E-H, L. dubius (Swain Reefs GBR, QM G305761, G305410, G305490; Whitsunday Is Qid., QM G302936). THE AUSTRALIAN ASCIDIACEA 4 381 Crea , -_ *» -_ H PLATE 3. A,B, Leptoclinides durus (Whitsunday Is GBR, QM G302947; Bonaparte Archipelago, QM G302888); C, L. echinus (Dampier Archipelago, QM G302871); D, L.exiguus (Point Turton S.A., SAM E2624); E, L. imperfectus (Albany W.A., QM G302883); F, L. kingi (Buccaneer Archipelago, QM G302870). G, L. levitatus (Rockingham W.A. QM G5456); H, L. maculatus (Tipara Reef $.A., QM G301572). 382 MEMOIRS OF THE QUEENSLAND MUSEUM G es jf n Ss. + oe a) ee. H PLATE 4. A, Leptoclinides rigidus (Wessel 1. W.A., QM G302926); B, L. rufus (Caloundra Qid, QM G308456); C, L. umbrosus with Lissoclinum roseum (Heron I. GBR, QM G308305); D, L. variegatus (Topgallant I. S.A., QM GH2426); E, L. volvus (Nuyts Archipelago S.A., QM GH926). F , Polysyncraton circulum (Swain Reefs GBR, QM G308407); G, P. dentatum (Bunker Bay W.A., SAM E2677); H, P. discoides (Port Davey Tas., SAM E2623). THE AUSTRALIAN ASCIDIACEA 4 383 ni _H pet eon 3 re C, Polysyncraton echinatum (Bowden Reef GBR, QM G300993; Whitsunday I. Qld, QM GH5370; Lizard I. GBR, QM G304176); D, P. flammeum (Caloundra Qld., QM G308461); E, P. glaucum (Swain Reefs GBR, QM G305589); F, P. meandraium (Caloundra Qld, QM G308460); G, P. millepore (Whitsunday Is Qld., QM G302945); H, P. multiforme (Houtman’s Abrolhos W.A., QM G30464]). 384 MEMOIRS OF THE QUEENSLAND MUSEUM a PLATE 6. A, Polysyncraton oceanium (Heron I. GBR, QM G308203); B, P. ofeutue (Swain Reefs GBR, QM G308378); C, P. palliolum (Rottnest I. W.A., QM G300988); D, P. pedunculatum (Flinders I. S.A., QM GH 2387); E, P. pseudorugosum (Bathurst I. N.T., QM G302910); F, P. purou (Heron I. GBR, QM G308230); G, P. rica (Kangaroo I. $.A., QM GH5426); H, P. rugosum (Swain Reefs GBR, QM G305554). THE AUSTRALIAN ASCIDIACEA 4 385 G = hens LC Ai titel H PLATE 7. A,B, Didemnum albopunctatum (Whitsunday Is Qld, QM GH5367 in situ and deck shot); C,D, D. arancium (Swain Reefs GBR, QM G308437 G305374); E, D. astrum (Swain Reefs GBR, QM G305409); F,H, D. bicolor (Top Gallant I. S.A., QM GH2410; Ward I.S.A., QM GH2409); G, D. chartaceum (W. Thailand, QM GH G300950). 386 MEMOIRS OF THE QUEENSLAND MUSEUM Cs - va a= 2 PLATE 8. A,B, Didemnum candidum (Swain Reefs GBR, QM G308391, G305557); C-E, D. clavum (Darwin N.T., QM G300930; Buccaneer Archipelago W.A., QM G302914, G300961); F, D. cuculliferum (Heron I. GBR, QM G308244); G, D. delectum (Edithburgh S.A., SAM E2625); H, D. elongatum (Tydeman Reef GBR, QM G302906). THE AUSTRALIAN ASCIDIACEA 4 387 PLATE 9. A, Didemnum fragile (Swain Reefs GBR, QM G308366); B, D. fragum (Point Souttar S.A., QM GH5438); C, D, D. fucatum (Deloraine I. Qld, QM GH5753); E,F, D. granulatum (Hardy Reef GBR. QM G300923; Black Reef GBR, QM GHS5379); G, D. grande (Whitsunday Is, QM GH5365); H, D. guttatum (Swain Reefs GBR, QM G305451). 388 MEMOIRS OF THE QUEENSLAND MUSEUM 5 v : eq H PLATE 10. A, Didemnum herba (Big Broadhurst Reef GBR, QM G308641); B, D. inveteratum (Lord Mayor Shoal W.A., QM G302922); C,D, D. incanum (Shell Harbour N.S.W., QM G304557; St Vincent Gulf S.A., QM G302766); E,F, D. jedanense (Heron I., GBR, QM G308294 — with few spicules; Cape Ruthiers W.A., QM G300976); G,H, D. jucundum (Esperance W.A., SAM E2693; Kangaroo I. S.A., QM G302897). THE AUSTRALIAN ASCIDIACEA 4 389 PLATE 11. A,B, Didemnum lissoclinum (Jervis Bay N.S.W., QM G302879; Kangaroo I. S.A., QM G300981); C-E, Didemnum membranaceum (Heron I., GBR, AMPI 148, G308255; Swain Reefs GBR. 305558); F, D. minisculum (Stansbury Jetty S.A., SAM E2647); G,H, D. moile (Bowden Reef GBR, QM G302921; Swain Reefs GBR, QM G305708). MEMOIRS OF THE QUEENSLAND MUSEUM 390 G = G PLATE 12. A,B, Didemnum multispirale (Capricorn Group GBR, QM G308313; AMPI 90); C,D, D. ossium (English Company I. N.T., QM G302908; Lord Mayor Shoal W.A., QM G300967); E, D. patulum (Western Port Vict., QM G302899); F-H, D. pecten (Pt. Souttar S.A.. QM GH 5439; Kangaroo I. 8.A., G300929; Jervis Bay N.S.W., QM G302898). THE AUSTRALIAN ASCIDIACEA 4 391 = . sa H PLATE 13. A-C, Didemnum pellucidum (Rottnest I. W.A., QM G300985; Yallingup W.A., SAM E2696; Port Giles S.A.. QM G300944); D-F, D. perplexum (Swain Reefs GBR, QM G305796-7 G305622); G, D. poecilomorpha (Gazelle Peninsula PNG, QM G302890); H, D. precocinum (Swain Reefs GBR, QM G308368). 392 MEMOIRS OF THE QUEENSLAND MUSEUM PLATE 14. A-D, Didemnum psammatode (Yorke Peninsula S.A., A,B, QM G300972; C, SAM E2611; D, Cape Wilberforce N.T., QM G302903); E-H, D. roberti (Bonaparte ‘Archipelago W.A., QM G302932; Bathurst I. N.T., QM G302907; Montebello Is W.A., QM G302937; Hut Point W.A., QM G300924). THE AUSTRALIAN ASCIDIACEA 4 393 =| = + 4 a ay ' 2 pe 206C31-43-3 TS Bere PLATE 15. A, Didemnum scopi Heron 1. GBR, QM G308213); B, C,.D. sordidum (Heron 1. GBR, QM G308303; Lord Mayor Shoal W.A., QM G300932); D, D. spadix (Busselton W.A., SAM E2686); E, D. spongioide (Hawkesbury I. Qld, QM GH5343); F, D. sucosum (Western Port Vict., QM G300980); G, D. vahatuio (Swain Reefs GBR, QM G305373); H, D. verdantum (Bathurst I. N.T., QM GH5358). 394 MEMOIRS OF THE QUEENSLAND MUSEUM “ys G : M3 AR.) ae PLATE 16. A, Trididemnum areolatum (Swain Reefs, QM G308426); B, T. discrepans (Phuket Thailand, QM G300938); C,D, T. lapidosum (Surrier I. W.A., QM G308687 G300983); E,F, T. nobile (Ceduna S.A., SAM E2630 E2633); G, T. nubilum(Heron I. GBR, QM G308443); H, 7. pigmentatum (Heron I. GBR, QM G308316). THE AUSTRALIAN ASCIDIACEA 4 395 PLATE 17. A, Trididemnum savignii (Nares Rock W.A., QM G300965); B-G, T. sibogae (Western Port Vict., QM G300971; Point Turton S.A., QM G300935, SAM E2605; Port Victoria S.A., SAM E2847; Kingston S.A., QM G302875; Arrawarra N.S.W., QM G302891); H, 7. spumosum (Edithburgh S.A., SAM E2616). 396 MEMOIRS OF THE QUEENSLAND MUSEUM PLATE 18. A,B, T. vermiforme (Beachport S.A., QM ean: (En D, Lissoclinum badium (Heron I. AMPI 206, 198); E-G, L. bistratum (Heron I. GBR; Big Broadhurst Reef GBR, OM G300978; Marion Reef AMPI 204, QM G10170); H, L. concavum (Flinders I. S.A., QM G308447). THE AUSTRALIAN ASCIDIACEA 4 397 PLATE 19. A, L. Lissoclinum conchylium (Moreton Bay Qld, QM G308499); B, ZL. durabile (Esperance W.A., SAM E2848); C, £. levitum (Ward I. S.A., QM GH2420); D, L. limosum (Swain Reefs GBR, QMG308419); E,F,. L. nebulosum (Whitsunday Is Qld., QM G302923); G,H, L. patella (Bowden Reef GBR, QM G300974; Madang PNG). 398 MEMOIRS OF THE QUEENSLAND MUSEUM | ay \ f Sr Gf 74 : ; ; d Pe ln = * an a < ae , 7 a * = “ - + ~- a ¢ Loe i ~ j i 7 ei ‘e PH A Ae) Pos PLATE 20. A-D, Dboaimin reginum (Swain Reefs GBR, QM G305456, G305800; Heron J. GBR, QM G308300 G: 308302); E,F, L. roseum (Heron I. GBR, QM G308309, G30831 1) see also Pi, 4C; G,H, Lissoclinun tasmanense (King George Sound W.A., SAM E2688; Point Norton S.A., SAM E2621). THE AUSTRALIAN ASCIDIACEA 4 399 G a ‘ a » > + H PLATE 21. A, Diplosoma ferrugeum (Heron I. GBR, QM G302952); B, C, D. listerianum (Beachport jetty S.A., QM G302880; Sydney Harbour, on sandstone blocks); D, D. simile (Rabaul PNG); E, D. translucidum (Cape Ruthiers W.A., QM G302946); F,G, D. velatum (Kangaroo I. S.A., QM G30291 1); H, D. virens, small colonies (Moreton Bay Qid). 400 MEMOIRS OF THE QUEENSLAND MUSEUM COLOUR PLATES, ACKNOWLEDGMENTS Aims Bioactivity Group, 1H; 2C,D,H; 3A-C,E-G; 4A; 5A,B,G; 6C,E,G; 7A,B,G; 8C-E,H; 9B-H;10A,B,F,H; 11A,B,G; 12C-H; 13A,F; 14A,B,D-H; 15E,F,H; 16B-D; 17A-C,F-G; 18A,B,F; 19E-G; 21B,E-G Clay Brice, West Australian Museum, 1A, 5H Alan Butler, University of Adelaide, 10D Neville Coleman, 1C,E; 11C; 12B; 16G; 18C,D,G; 19A; 21H Tim Glasby, 21C Karen Gowlett Holmes, 3D; 4 GH; 8G; 10G; 11F; 13B; 14C; 15D; 16E,F; 17D,E,H; 19B; 20GH Nigel Holmes, 1B; 2A; 4D,E; 6D; 7F,G; 18H; 19C Susan List, Queensland Museum, 1D; 2E-G; 4F; 5C,E; 6B,H; 7C-E; 8A,B; 9A; 11E,H; 13C-E,G; 15A,G; 16A; 19D; 20A,B L. Miller, Water Board of Sydney, 10C Myriam Preker, Heron I. Research Station, 1F,G;4C; 6A,F; 8F; 10E; 11D; 12A; 13H; 15B,C; 16H; 20C-F;21A John Ryland, 18E W.H. Sasse, 2B Scoresby A. Shepherd, 3H Roger Steene, 19H; 21D Jeff Wright, Queensland Museum, 4B; 5D,F THE AUSTRALIAN ASCIDIACEA 4 401 INDEX TO TAXONOMIC NAMES (pages on which formal descriptions and figures appear are shown in bold) ahdaminale, Lissoclinum, 292 295 acteulus, Leptoclinides, 35 37 38-62 63 73 ahu, Didemnum 205 207, albamaculatus, Leptoclinides, 35 38 39 78 albidum, Leptoelinym, 185 albopunctatum, Didemnum, 11 121681 93 140 142 144 145 146 147 148-9 179 191 194 213 216.219 224 229 254 331 335 amiculum, Trididemnum, 253 254 256 287 270 274 anoi, Didemnum, 167 168 169 apertus, Leptaclinides, 33 34 36 42 51 53 54 Aplousobranchia, 1 7 15 apuroto, Didemnum, 144 145 153 179 193 212 arafurensis, Polysyncraton, 89 91 93 95 103 105 106 109 112 114 118 120 125 129 urancium, Didemnum, 1290 96 140 142 145 150+1 157 162 197 200 214 218 229 arealutum, Trididemnum, 253 254 255 256 258 259 260 276 279 281 283 285 areniferus, Dumus, 181 Askonides, 29 32 44 46 65; see also: coelenteratus, imperfectus aspiculatum, Polvsyneraton, 89 9) 121 122 126 127 128 130 131 Astellium spangifarme, 339 astrum, Didemnum, 143 145 147 151 152 200241 ata, Diplosama, 13 183 322 336 339 345 Atriolum, 5678 101112131415 16.1718 19-21 2331 32 33 34 36 254; see also: bucinum, eversum, lilium, marinense, marsupialis, robustum, tubiporun atropunctanum, Diplasoma, 339 alrapunctatum, Leptaclinum, 339 august, Didemnum, 5 155 166 207 219 aurantivus, Leptoclinides, 37 aureum group, 293 295 296 311 aureum, Lissoclinum, 291 293 hadium, Lissoclinum, || 12 216 292 294 205 296 297 301 306 310 314 315 321 banneri, Trididemnum, 258 benda, Trididemnum, 252 bicolor, Didemnum, |14 143 144 145 152-3 193 215 biglutinum, Didemnum, 148 149 bimasculum, Didemnum, 140 144 147 148 155 246 bisectatum, Didemnum, 140 143 144 148 154 188 246 bistratum, Didemmum, 298 bistratum, Lissaclinum, 8 12 13 17 208 265 292 293 294 298-300 315 317 325 328 330 Botryllus stewartensis, 182 brandi group, 33 34 brandi, Leptoclinides, 10 12 13 17 18 2021 34 35 36 40-2 54 62 70 86 145 brevioris,Didenmum, 144 216 bucinum, Atriolum, 21-2 24 25 caelatum, Trididemnum, 108 253 259 260 274 caelestis, Leptoclinides, 35 42-3 74 (83 caesium, Didenmum, 12 90 105 140 143 144 146 147 150 155-7 162 171 186189 196 224 232 24024) calificiforme, Leptoclinum, 347 caliginosum, Lissoclinunt, 11 292 294 296 298 300-1 302 305 315 321 calycis, Lissoclinum, 246 293 295 296 303-3 313 314 319 325 326 cundidum, Didemmum, 12 140 144147 148 155 187-60 169 177 185 206 21] 226 228 229 234 236 capensis, Leptoclinides, 18 caplivum, Didenuum, 144 226 varduus, Leptoclinides, 34 40 43-4 49 carnosui, Diplosoma, 339 cavernosus, Leptoclinides, 33 35 36 40 44-6 47 48 62 67 77 78 81 cerebriforme group, 253 cerebrifol'me, Trididemmum, 5 202 253 254 255 257 272 274 278 283 286 289 291 cevlonicumt, Didemnum, 238 chamaelean, Diplosoma, 339 chartaceum, Didemnum, 12 97 115 128 132 140 14] 143 147 150 152 157 160-2 197 199 200 214 229 246 298 chandrilla, Palysyneraton, 9) 92 106 108 122 cineraceum, Dideminum, 140 184 194 197 Ciona, 7 circulum, Palysyneraten, 27 49 9193 94-6 104 112 118 125 128 136 236 claviforntis, Euclavella, 182 clavum, Dideminum, 8 12 140 141 143 146 162-4 169 188 204 206 207 226 234 248 clinides, Trididemnum, 17 18 177 248 250 253 254 255 256 260-2 266 269 271 276 292 300 Clitella, 17 11 12 14 15 18 19 89 280. 332-3: see also; nutricula Coelocarnius, 20; see also; huxley! cuvelenteratus, Askonides, 29 46 caelenteratus group, 33 34 42 71 coelenteratus, Leptoclinides, 12 20 3| 3233 35424647 48 67 comins, Leptoclinides, 14 34 48-9 224 compactus, Leptoclinides, 33 35 37 49-30 63 67 72 78 83 87 92 , complexum, Didemnum, & 143 164-6 179 concavurn, Lissoclinum, 12.123 293 295 296 303-8 307 308 311 314 332 conchytium, Lissoelinum, 11 12294295 301 304 303-6 310 confirmatus, Leptoclinides, 12 35 50-3 74 constellatus, Leptoclinides, 35 51-2 78 contortum, Didemnum, 145 24) carnutum, Lissoclinum, 293 295 305 311 crescente, Didemnum, 12 143 166-7 220 241 248 cretaceum, Leptoclinum, 157 eristatum, Dididemmum, 74 92 |37 139255 261 262-3 erystallinum, Diplosoma, 339 erystallinum, Pseudadidemnum, 339 erystallinum, Trididemnum, 8 232 253 255 263-4 274 402 cuculliferum, Didemnum, 9 12 103 141 143 146 162 164 167-9 171 176 188 202 206 211 234 238 240 cuculliferum, Diplosomoides, 167 cuspidatum, Didemnum, 52 146 157 cuspidatus, Leptoclinides, 12 33 34 35 37 51 52-4 146 196 cyanophorum, Trididemnum, 276 cyclops group, 9 253 254 cevclops, Trididemnum, 11 13 14253 254 255 263-6 271 275 276 278 292 298 300 319 323 cygnuus, Didemnum, 141 143 169-71 193 224 240 Cystodytes, 7 319 326 dealbatum, Didemnum, 145 146 149 197 271 272 delectum, Didemnum, 118 144 171-3 193 198 202 203 204 207 252 dentatum, Polysyncraton, 14 91 96-8 104 Diazona, Diazonidae, 17 dicolla, Didemnum, 140 145 Didemnoides patella, 315 Didemnoides sulcatum, 315 Didemnoides ternatanum, 209 315 318 Didemnopsis jolense, 267 Didemnum, 15789111213 1415 161718203678 81 86 89 90 108 140-8 155 158 160 164 171 184 196 208 211 216 229 238 246 250 263 291 292 293 313 330 335; see also: ahu, albopunctatum, apuroto, arancium, astrum, augusti, bicolor, biglutinum, bimasculum, bisectatum, bistratum, brevioris, caesium, candidum, captivum, cevlonicum, chartaceum, cineraceum, clavum, complexum, contortum, crescente, cuculliferum, cygnuus, delectum, diffundum, digestum, “diminutum”, dispersum, dorotubu, effusium, elikapae, elongatum, etiolum, fimbriatum, flagellatum, flavoviride, fragile, fragum, Jraternum, frondescens, fucatum, fucatus, fuscum, gottschaldti, grande, granulatum, guttatum, herba, hiopaa, incanum, inveteratum, jedanense, jucundum, lacertosum, lambitum, levitas, ligulum, linatum, linguiferum, lissoclinum, macrosiphonicum, macrospiculatum, maculosum, makropnous, mantile, meandrium, megasterix, membranaceum, microthoracicum, minisculum, misakiense, molle, monile, mortenseni, moseleyi, multispirale, mutabile, nekozita, nigricans, nigrum, nocturnum, oblitum, obscurum, okudae, ossium, pacificum, parancium, parau, patulum, pecten, pele, pellucidum, perlucidum, perplexum, pitipiri, poecilomorpha, productum, proliferum, precocinum, psamathodes, psammatode, psammatodes, pseudodiplosoma, ramosum, recurvatum, reticulatum, risirense, roberti, rodriguesi, rubeum, scopi, sibogae, sordidum, spadix, sphaericum, spongioide, spongioides, stercoratum, stragulum, sucosum, sycon, tabulatum, tenebricosum, ternatanum, ternerratum, theca, timorense, toafene, tonga, turritum, uturoa, vahatuio, verdantum, via, viride, voeltzkowi, vulgare, volky MEMOIRS OF THE QUEENSLAND MUSEUM diemenensis, Leptoclinides, 37 42 diffundum, Didemnum, 144 145 153 193 212 digestum, Didemnum, 145 146 213 236 246 330 “diminutum”, Didemnum, 176 Diplosoma, 16789101112 131415 161718198990 103 141 149 157 173 196 197 254 265 280 286 291 292 294 313 322 323 335-6; see also: ata, carnosum, chamaelean, crystallinum, ferrugeum, gelatinosum, inflatum, lacteum, listeri, listerianum, macdonaldi, matie, midori, mitsukurii, multifidum, multipapillatum, pavonia, pizoni, punctatum-listeri, rayneri, redika, simile, similis, translucidum, velatum, virens, viride Diplosomoides, see: cuculliferum, molle, ostrearium, triangulum discoides, Polysyncraton, 91 93 98-9 103 104 112 121 133 discrepans, Leptoclinum, 267 discrepans, Trididemnum, 253 254 263 266 267 dispersum, Didemnum, 146 dispersum group, 254 dispersum, Trididemnum, 253 254 255 256 262 267-70 276 Distaplia, \1 doboensis, Leptoclinides, 35 dorotubu, Didemnum, 229 dromide, Polysyncraton, 90 97 99-101 111 112 121 128 133 dubium, Polysyncraton, 36 54 67 dubius group, 18 33 34 37 42 43 44 46 59 67 68 69 70 75 318 dubius, Leptoclinides, 11 18 33 36 54-7 61 67 68 69 70 75 81 duminus, Leptoclinides, 37 Dumus areniferus, 181 durabile, Lissoclinum, 11 294 295 298 305 306-7 308 314 durus, Leptoclinides, 10 33 34 36 54 56 57-9 69 70 75 114 echinatum, Polysyncraton, 9 10 91 101-3 105 109 118 141 164 169 Echinoclinum 292 293; see also: philippinensis, triangulum, verrilli echinus, Leptoclinides, 8 12 33 34 43 56 59-61 70 75 effusium, Didemnum, 12 140 141 142 173 174 208 280 elikapekae, Didemnum, 197 elongatum, Didemnum, 143 146 147 173-5 186 189 203 212 218 224 232 244 257 erinaceus, Leptoclinides, 15 35 38 61-2 etiolum, Didemnum, 11 12 141 144 175-6 177 191 205 208 248 250 Euclavella claviformis, 182 Eucoelium, 319 Eudistoma, 20 eversum, Atriolum, 19 20 21 22-4 25 32 exiguus, Leptoclinides, 34 35 38 49 62-3 78 86 pacificense, faroensis, Leptoclinides, 18 31 ferrugeum, Diplosoma, 10 14 292 323 335 336 337-9 345 347 THE AUSTRALIAN ASCIDIACEA 4 Jetia, Trididemnum, 255 256 Jimbriatum, Didemnum, 5 Jlammeum, Polysyncraten, 91 93 97 99 13-4 Nagellatum, Didemnum, 197 flavoviride, Didemnum, 141 144 176-7 19) 208 250 Jragile, Didemnum, 143 144 146 147 148 149 157 159 177-9 206 216 219 217 228 229 246 Jragile group, 11 293 294 298 301 306 321 fragile, Lissoclinum, 292 294 295 298.305 306 307 315 319 321 Jragum, Didemnum, 4 12 143 145 171 179-82 211 222 224 232 241 ; Jraternum, Dideninum, 205 207 frondescens, Didemnum, 283 286 frondescens, Trididemnum, 283 286 Jucatum, Didemnum, 8 13 29 140 142 146 182-4 230 323 fucatus, Didemmum, 146 \82 fungiformis, Leptoclinides, 14 15 34 37 63-5 72 88 89 108 122 fuscum, Didemnum, 1\ 12 143 147 159 162 169 184-5 206 226 229 235 236 fuscum, Hypurgon, 229 fuseum, Polysyncraton, 4 92 112 velatinosum, Didemnuin, 339 gelatinosum, Diplosoma, 339 gelatinosum, Leptoclinum, 339 glaucum, Polysyneraton, 89 91 92 93 104-5 115 145 215 glauerti, Leptoclinides, 32 gottschaldti, Didemnum, 298 grande, Didemnum, 1214105 117 120-143 [44 146 155 157 185-8 189 201 203 207 244) granosum, Trididenmun, 255 granulatum, Didenmum, 144 147 157 187 188-9 224 guttatum, Didemnum, 140 141 144 171 175 176 186 189-90 218 224 227 250 hawaiiensis, Leptocliniides, 35 herba, Didemmum, 141 144 176 189-91 250 hiopaa, Didemmum, 142 149 191 192 197 Mnacleyi, Coelocormus, 32 Hypodistoma, 20; see also; fantasiamim, deerratum Hypurgon fuseum, 229 Hypurgan skeati, 229 imperfectus, Askonides, 44 65 intperfectus, Leptoclinides, 12 33 34 46 49 65 66 73 78 83 ineanun, Didemnum, 4 12.144 166173 191-3 211 252 inflatum, Diplosoma, 336 343 345 infundibulum, Polysyncraten, 1491 106 108 120 139 japonicum, Lissoclinum, 292 295 298 306 315 jedanense, Didenmiyn, 12 78 86 [40 141 142 146 148 149 150 157 173 185 1947 215 214 224 229 230) 234 243 280 Jolense, Didemnopsis, 267 jucundum, Didemnum, 12 143 153 197-9 243 43 Jugosum, Leptociinum, 106 179 Jugosum, Palysvncraton, 91 106-8 109 115.122 130 139 1st king, Leptoelinides, 33 34 56 57 59 67-974 75 lacertosym, Didemnum, \43 152 199-200 206 226 24! 243 lacteum, Diplosame, 339 lambitum, Didemnum, 5 108 143 166 (79 181 202 lapidosum, Trididenmum, § 9 12 17 253 254 255 249 270-1 286 Leptoclinides, 156789 101012 13 141516171819 20 21 31-7 49 $1 89 90 125 140 141 183 253 254 271; see also: aciculus, albamaculams, apertus, auranticus, brandi, caelestis, capensis, cardius, cavernosus, Coelenteratus, comitus, compacts, confirmatus, canstellatus, cuspldatus, diemenensis, doboensis, dubius, duminus, durus, echinus, erinaceus, exiguus, faroensis, Jungiformis, hawatiensis, imperfectus, kingi, levitamus, lissus, longicollis, maculatus, niadara, magnistellus, margaritiferae, marmoratus, multilobatus, novaezelandiae, ocellatus, oscitans, placidus, quadratum, ramosum, reticulatus, rigidus, robiginis, rufus, seminudus, sluiteri, sparsus, sulewesil, unbrosus, uniorbis, unitestis, variegetus, volvus Leptoclinum, see: albidum, atropunctatum, calificiforme, discrepans, gelatinosum, jugosum, listerianum, macdonaldi, macrolobium, midor|, mitsukuri, molle, moseleyi, multifidum, namei, okai, ostrearium, patella, patulum, perspicunm, psamathodes, psammatodes, punctatum, ramosum, simile, lenue, tonge, translucidum, varium, virens, viride levitatus, Leptoclinides, 12 15 33 34 43 56 61 69-7075 levitas, Didemnum, 143 150 157 197 199 200 214 215 levitum, Lissoclinum, 294 307-8 ligulum, Didemnwa, 105 140 145 150 152 200 214 215 216 218 lilium, Arriolum, 11 19 20.2) 22 23 24-5 27 29 32 limosum, Lissoclinum, 294 296 308-10 323 332 linatum, Didemnum, 143 171 200-2 linguiferum, Didemnum, 140 145 147 200 218 Lissoclimon, 157810111213 1415161718 193689 103 108 149 196 254 265 280 291-6 300 313 316 319 327 352 333 334 335; see also: abdominale. aureum, badium, bistratum, caliginosum, calveis, concavum, conchylium, cornutum, durabile, Jragile, japonicum, levitum, limosum, maculatun, moalle, multifidum, multitestis, nebulosum, notti, ostrearium, pacificense, patella, philippinensts, polyorchis, pulvinum, punclatum, reginwn, roseum, seme, spongium, taratara, tasmanense, tenerum, ftesliculata, textrinum, timorense, trianenlum, tuhelavae, tunicatum, varean, variabile, verrilll, voeltzkowi, vulgare lissactinum, Didemrnum, 8 9 12 143 145 166 167 1A WN 202 207 218 224 252 272 404 lissas group, 34 lissus, Leptoclinides; 34 42 52 547077 81 listeri, Diplosomea, 339 listerianum, Diplosoma, 310 331 335 336 337 33941 345 347 listerianum, Leptaclinum, 335 listerianum, Pseudodidemnum, 339 lithostrotum, Palysyneraton, 92 93 103 145 lodix, Palysyneraton, 9 108-9 longicollis, Leptaclinides, 12.15 33 35 42 49 70-2 macdonaldi, Diplosomea, 336 337 334 341 nuwdonaldl, Leptoctiiuwn, 337 339 macrolobium, Leptoctinum, 339 macrosiphonium, Didemnum, 144 173 175 202-3219 224 240 252 macrospiculanim, Didermmuni, \47 maculatun, Lissoclinum, 292 294 295 309 310 maculatus, Leptoclinides, 34 35 38 49 52 62 63 67 72-3 79 83 86 maculasum, Didemmnumn, 140 147 159 madara, Leptoclinides, 35 magnetae, Polvsyneraton, 89 90 9199 100 109-11 112 125 139 magnilarvum, Polysyneraton, 91 101 121122 127131 magnistellus, Leptoclinides, 16 35 51 62 73-4 92 137 mahenum, Polysvicraten, 92 makrapnous, Dideninum, 146 185 186 187 224238 240 mantile, Didemmnum, \44 203-5 248 morgaritiferae, Leptoelinides, 37 marinense, Atriatum, 1) 182021 23 2425-7 2931211 mermoratus, Leptoclinides. 35 36 37 79 81 146 196 marmoratum, Leptoclinum, 255 mormoratumn, Palysvneraion, 81 marnworatum, Trididenmum, 252 255 marmareus, Leptaclinides, 37 87 marsupialis, Atriolum, 21 marsupialis, Leptaclinides, 20 21 31 34 35 36 42 54 matie, Diplosoma, 347 348 349 350 meandraium, Polysyneratan, 4 14 89 90) 92 93 94 96.97 101 103 110 111-3 118 128 133 246 meanadriyum, Didemnumn, 315 megasterix, Didemmum, \47 155 UST membranaceum, Didemnum, 12 14 141 143 146 148 159 162 164 166 169 173 188 202 205-7 211 226 234 252 mereti, Lissoclinum, 294 295 310 319 326 331 micrathoracicum, Didemnum, 144 173 202 203.207 208 220 midori, Diplosoma, 341 343 midori, Leptoctinum, 341 millenore, Polysyneraton, 91 93 94 113-4 125 153 miniatum group, 254 miniatum, Trididenmum, 145 146 177 248 280 253 254 255 256 262 265 270 271-2 292 300 minisculum, Didenmum, 12 143 173 207-8 misakiense, Didenummm, 216 218 238 mitsukurii, Diplosama, 336 mitsukurii, Leptocliinum, 339 molle, Didemimen, 8 13 14 17 25 26 108 1 25 140 141 144 176 191 208-11 243 250 315 321 325 MEMOIRS OF THE QUEENSLAND MUSEUM molle, Diplosamaides, 208 malle, Leptoclinum, 298 malle, Lissoclinum, 208 298 318 monile, Dideninum, 143 211 243 mortenseni, Didemnum, 74 137 139 262 mortenseni, Polysyneraton, 5 51 73 74 92 137 263 moselevi, Didenmum, 137139 144 152 167 168169171 175 188 191 205 207 210 211-3 225 234 250 252 moseleyi, Leptoclinum, 211 multifidum, Diplosoma, 311 multitidum, Leptoclinum, 311 multifidumn, Lissoclinum 291 293 295 305 311 312 multiforme, Polysyncraton, 91 92 93 105 114-5 116 117 120 128 162 multilobata, Leptaclinides, 74 multilobatus, Leptaclinides, 33 34 56 69 74-5 multipapillae, Polysyneraton, 11 18 89 90 92 336 multipapillatum, Diplasoma, 11 15 92 multipapillatus, Leptoclinides, 36 42 multispirale, Didemnum, 12 90 140 143 [46 149 150 152 157 162 186 196 197 200 213-5 246 muiltitestis, Lissoclinum, 291 293 295 311 miutahile, Didentnum, 143 147 152.155 200 213 214215 namei, Leptoclinum, 36 natalense, Trididemmum, 253 255 2 nebulosum, Lissoclinum, 13 14 183 311-4 323.330 nekozita, Dielemmum, 167 169 nigricans, Didemnum, \47 nigrepunctatum, Polysyacraton, 81 92 99 100 nigrum, Didemnum, 60 162 nobile, Trididemnum, 8 108 173 253 254 255 260 263 272-4 279 285 287 288 291 nocturnum, Didenmum, 147 157 nattl, Lisseclinum, 295 novaerelandiae, Leptoclinides, 37 nube, Trididemmum, 252 253 253 255 263 mubllum, Trididenmunt, 177 248 250 253 254 255 256 262 271 274-6 nutricula, Clitella, 12 14 58 263 285 246 291 293 295 332 3334 vhlinm, Didemnum, 12 97 142 144 215-6 obscurum, Didenmum, 160 162 oceanium, Polysyneraion, 89 90 9] 93 115-7 120 139 188 acellatus, Leptaclinides, 36 ocellatunt, Polysyneraton, 36 81 okai, Leptoclinum, 339 okudai, Didenmum, 197 orbieulum, Polysyncraron, 16 91 96 107 117-8 119 121 132 136 137 173 236 331 335 oseitans, Leptoclinides, 52 54 79 81 ossium, Didemmum, § 9 114 140 143 145 147 150 151 153 175 187 193 215 216-8 232 236 238 astrearium, Diplosomnides, 314 319 321 ostrearium, Leproclinum, 314 astrearium, Lissoctinum, 11 12 292 294 295 306 308 314-5 32) otuetue, Palysvacraton, 90 92 110 112 118-119 128 THE AUSTRALIAN ASCIDIACEA 4 paa, Didemnum, 147 152 200 pachydermatina group, 182 pacificense, Echinoclinum, 323 pacificense, Lissoclinum, 292 293 295 296 303 319 325 326 327 pacifieum, Didemnum, 197 pallialum, Palysyncraton, 89 91 117 118-20 155 188 papyrus, Polysyneraton, 91 92 98 112 120-1 122 paraclinides, Trididemnum, 177 253 254 255 256 260 262 275 276 292 paracyclops, Trididemnum, 253 254 255 264 265 275 276-8 paradoxum, Polysyneratan, 4 49 50 92.98 118 120121 133 243 parancium, Didemnumm, \\ 140 143 145 147 218 219 parau, Didemnum, 147 179 219 patella, Didemnoides, 315 318 patella, Didemnum, 298 315 patella, Lepioclinum, 315 patella, Lissoclinum 12 17 3657 29) 292 293 294 300 315-8 patulum, Didemnum, 12 144 155 166-203 207 219-220 224 240 243 patilun, Leptoclinum, 29 pavimentum, Polysyneraton, 9293 105 VIL S117 135 pavonia, Diplosoma, 347 348 349 pecten, Didemnum, 143 171 181 220-2 224 24] peduneulatum, Palysyneratan, 65 85 90 91 108 121-2 127 130 131 pele, Didemmum, \88 pellucidum, Didemmnum, 12.49 143.181 199 202 222-4 252 perlucidum, Didemnum, \47 perplexum, Didemnum, 12 144 146 147 149 159 185 186 188 196 206 207 224-6 234 perspicuum, Leptoclinum, 343 345 philippinensis, Echinoclinum, 330 331 philippinense, Lissoclinum, 296 pigmentatum, Trididemnum, 146 253 254 254 260 272 274 277 278-9 285 286 289 pitipiri, Didemnum, 11 140 145 147 152 219 pizani, Diplasuma, 239 plactedus, Leptoctinides, 12.33 35 70 73-7 83 87 planum, Trididenmum, 255 260 288 289 poecilomorpha, Didemmim, 11 140 141 144 145 147 176 177 189 190 226-8 248 250 292 Polyeitorella, 3\9 Polyclinidae, 11 17 polyorchis, Lissoclinum, 123 293 296 305 311 332 polyorchis, Tridideminum, 256 260 Polysoma, 293, see also: festiculatum Polysyneraton, 1457891011 121314151617 18 19 36 89-93 94 97 105 108 115 122 125 135 139 141] 150 157 211 229 252 254 256 280 291 292 330 335; see also: arafurensis, aspiculatum, thondrilla, circulum, dentatum, discoides, dronide, dubium, echinatum, flammeum, fuscum, glaucum, infundibulum, jugosum, lithastretum, lodix, magnetae, magnilarvum, mahenuni, marmoratum, mahenum, marmoratum, meandrutum, millepare, mortenseni, multiforme, multipapillae, nigropunctatum, oceanium, ocellatum, arbiculum, otuetue, palliolum, papyrus, pedunculatum, pontoniae, pura, psevdoryzasum, pulehryum, purou, reeurvatum, regulum, rica, robuxium, rubitapum, rufum, rugosum, sagamiana, seobinum, scorteum, sideris, lasmadnense, tegetum, tenuicutis, thallomorpha, victoriensis pontoniae, Polyyyneraton, 89 91 122-3 294 305 332 pore, Polysyneraton, 89 93 96 103 precocinum, Didemnunr, 90 140 142 146 148 149 150 157 178.179 197214 228-9 Prochloron, | 131417 18 40.56 57 58 70 90 94 110 117 127 134 141 150 155 160 168 176 177 186 L91 199 208 209 210 211 214 228 245 247 248 250 253 254 261 265 269 271 277 278 286 292 293 294 299 30() 313 316 317 318 319 325 328 329 330 335 336 341 342 343 348 productum, Didemraun, 243 proliferum, Didemnum, 177 179 psamathodes, Leptoclinum, 229 psammatoie, Didemnum, 8 18 142 183 184211 229-40 243 286 psammatodes, Didemnum, 229 psammatodes, Leptoclinum, 229 Pseudodidemnum, see: crystallinum, listerianum, zastearium pseudodiplosoma, Didemnum, 194 197 pseudodiplosoma, Trididemnum, 12 15 173 197 152 254-5 279 28) 287 288. pseudorugosum, Polysyncraton, 91 94 VOL WN 14 123-5 129 135 pulchrum, Palysyneraton, 89 91 96 125-6 pulvinum, Lissoclinum, 264 298 punctetum, group, 292 293 294 296 334 punctatum, Leptoclinum, 339 punctatum, Lissoclinum, 18 208 292 294 317 318-9 puron, Polysyncraton, 89 90 91 92 103-112 115 LL7 148 121 122 126-8.131 133 246 punctatum-listerl, Diplosoma, 339 Pyura, 182 quadratum, Leptaclinides, 36 ramosum, Didenmum, 146 278 233 286 ramosum, Leptoclinides, 283 ramosunm, Leptoclinum, 283 286 ravarava, Lissoclinum, 294 295 296 310 319 323 332 raynerl, Diplosamad, 335 339 recurvatum, Didenmum, 144 146 147 148 155 179 188 246 recurvatum, Palysyneraton, 89 93 123 147 redika, Diplosama, 336 reginun, Lissoclinum, (1 292294 295 296 301 305 306 314 315 319-22 regulum, Polysyneraton, 91 109 120 128-30 reticulatum, Didemnum, 36 52.78 79 81 146 155 194 196 197 reficulatus, Leptoclinides, 36 37 77 78 79 81 86 87 137 139 194 reticularum, Leptoclinum, 196 406 rica, Polysyneraron, 9) 108 129 130 tizidus, Leptoclinides, \2 14 34 35 38 40 5] 52 62 63 77-9 83 85 risirense, Didemnum, 140 Ritterellidae, 11 181 roberti, Didemnum, 108 143 145 166 171 LBL 191 222 230-2 236 238 24] rohiginis, Leptaclinides, 86 vobustum, Atriolum, 56711 13 192021 23 2425 27-9 31184 rohustum, Polysyncraton, 490-91 121 127 130-1 rodriguesi, Didemnum, \88 224 225 226 roseum, Lixsoclinum, 183 291 292 294 310 322-3 336 339 rottnesti, Didenmum, 5 rubeum, Didemnum, \40 144 147 148 246 rubitapum, Polysyneraton, 91 109 12) 131-2 rufum, Polysyneratan, 79 rufus group, 33 34 rufus, Leptoclinides, 33 34 35 36 37 46 47 49 57 62 65 70 71 72:77 78 79-82 83 85 86 146 194 196 272 rugosum, Polysyncraton, 89 91 92.97 99 112 113 121 129 132-3 sagamiana, Polysyneraton, 93 103 servignil group, 16 253 27) 274 280 335 savignii, Trididemnum, 18 )48 253 254 255 258 260 263 267 279 281-3 285 288 289 scobinum, Polvsyncraton, 90 91 94 105 106 118 134 135 scopi, Didemnum, 105 141 144 164 1692324 243 244 scorteum, Polysyncraton, 91 135-6 seminudus, Leptoclinides, 35 38 52.78 79 82-3 sente, Lissoclinum, 12292 293 295 296 323-5 326 327 sibogae, Didemnum, 283 sibagae, Trididemnum, & 12 146 232 253 254 255 256 257 263 267 270 272 274 279 283-6 291 sideris, Palysyneraton, 91 109 118 132 136-7 139 Sigillina deerrata, 20 simile, Diplosoma, 157 335 336 341-3 347 349 simile, Leptoclinum, 341 347 similis, Diplosoma, 315 341 skeati, Hypurgon, 229 sluiteri, Leptoclinides, 37 sordidum, Didenmum, 11 12 105 143 185 205 234-6 7 spadix, Didemnum, 11 12 143 185 222 236-7 sparsus, Leptoclinides, 377981 sphaericum, Didemnum, 159 169 spiculatum, Trididemnum, 5 197 276 spongia, Trididenmum, 252 253 256 174 286 spongifarme, Asteilium, 339 spongijarme, Diplasoma, 339 341 spongioide, Didemnum, 8 9 143 145 166 181 202 232 236-8 spongioldes, Didenmum, 181 216 230 232 240 sponginan, Lissaclinum, \08 292 293 324 325 stercoratum, Didemnum, 18 148 230 stewarlensis, Botryllus, 182 stragulum, Didermnum, 141 144 146 164 167 169 185 186 193 203 234 238-40 MEMOIRS OF THE QUEENSLAND MUSEUM aTrigasnm, Tridideninum, 248 250 253 254 256 262275 292 300 sucosum, Didemmum, 143 18] 222 224 232 236238 239 sulawesii, Leptoelinides, 35 49 52 54 79 83 $4 sulcatum, Didemnoides, 315 symbioticun, Trididemmum, 266 speon, Didemnum, 209 tabularum, Didemnum, 143 145 146 241—2 246 laratara, Lissaclinum, 246 293 295 296 313 314 324 323-6 331 tasmanense, Lissoclinum, 292 293 295 303 310319325 326-7 lasmanense, Polysyncraton, 86 91 92 137-9 262 263 tasmanensis, Cystodytes, 326 tectum, Trididemnum, 254 287 288 tegetum, Palysyncraton, 74 87 91 109 137 137-9 fegulum, Trididemnum, 130 253 262 267 268 lenebricosum, Didemnum, 281 283 tenerum, Lissoclinum, 252 tenue, Leptoclinum, 160 tenuicutis, Polysyneraton, 9\ 138 139 ternatanum, Didemnoides, 209 315 318 rernatanum, Didemnum, 208 232 241 243 315 ternerratum, Didemnum, 143 199 230 232 241-3 lesticulatum, Lissoctlinur, 311 lesticulatum, Polysama, 293 3\1 rexrrinum, Lissoclinum, 292 296 thallomerpha, Palysyneraton, 113 theca, Didemnum, 142 230 243 245 timorense group, 293 timorense, Lissoclinum, 13 14 17 146 29| 292 293 294 296 298 300 305 317 328-30 timorensis, Didemnum, 146 328 toafene, Didemnum, 148 193 tomarahi, Trididemnum, 253 254 255 260 279 281 288-9 onga, Didemnum, \44 175 203 205 226 240 243-4 tonga, Leptoclinum, 243 translucidum, Diplosoma, 335 336 339 34 | 343-5 347 translucidum, Leptoclinum, 343 345 triangulum, Diplosamoides, 330 iriangulum, Echinoclinum, 325 326 330 triangulum group, 292 293 334 wriangulum, Lissoclinum, 292 293 295 296 303 310313 314 319 326 330-1 trididemni, Synechoeystis, 268 Trididemnum, 1578911 12131415 161718203289 108 149 202 252-6 260 262 263 271 280.29) 292 313 331 335; see also; amiculum, areolatum, benda, caeletum, cerebriforme, elinides, eristatum, crystallinum, cyanaphorum, cyclops, discrepans, dispersum, fetia, frondescens, eranosum, lapidosum, marmoratum, miniatum, natalenye, nobile, nube, mtbilum, paractinides, paracyelops, pigmentatum, planum, polyorchis, pseudodiplosoma, savignii, sibogae, spiculatum, Spongia, spumosum, strigosuin, syimbloticum, tectum, tegu/um, tomarahi, vahaereere, vermiforme, viride THE AUSTRALIAN ASCIDIACEA 4 tubiporum, Atriolum, 14 20 21 29-31 48 tuheiavae, Lissoclinum, 293 296 303 325 tunicatum, Lissoclinum, 294 296 310 turritum, Didemnum, 167 169 202 umbrosus, Leptoclinides, 14 34 63 83-5 uniorbis, Leptoclinides, 36 59 114 unitestis, Leptoclindes, 18 20 uturoa, Didemnum, 12 140 142 144 145 148 155 244-6 314 330 vahaereere, Trididemnum, 253 254 256 279 280 286 289 vahatuio, Didemnum, 12 85 143 243 246-7 250 vareau, Lissoclinum, 294 295 296 298 301 306 322 variabile, Lissoclinum, 14 16 254 291 294 305 329 331-2 335 variegatus, Leptoclinides, 12 33 35 63 72 77 79 83 86-7 139 varium, Leptoclinum, 347 velatum, Diplosoma, \2 335 336 343 345-7 vermiforme, Trididemnum, 8 253 254 255 272 274 285 289-91 verrilli, Echinoclinum, 326 verrilli group, 292 293 334 407 verrilli, Lissoclinum, 293 296 303 323 325 326 327 verdantum, Didemnum, 11 141 144 176 190 191 205 247-8 250 versicolor, Diplosoma, 336 339 345 via, Didemnum, 144 248-9 victoriensis, Polysyncraton, 5 virens, Diplosoma, 8 13 208 265 271 335 336 341 343 347-9 virens, Leptoclinum, 347 viride, Didemnum, 11 12 14 141 144 148 176 189 190 191 226 227 240 246 248 248-50 292 347 viride, Diplosoma, 347 viride, Leptoclinum, 248 347 viride, Trididemnum, 248 250 260 271 274 275 voeltzkowi, Didemnum, 298 328 330 voeltzkowi, Lissoclinum, 13 298 300 328 330 volvus group, 34 37 65 volvus, Leptoclinides, 14 34 87-9 122 vulgare, Didemnum, 144 193 198 211 250-2 vulgare, Lissoclinum, 293 296 313 326 yolky, Didemnum, 157 zosterarium, Pseudodidemnum, 339 THE AUSTRALIAN ASCIDIACEA PARTS 1-3, CORRIGENDA PATRICIA KOTT Kott, P. 2001 08 15: The Australian Ascidiacea parts 1-3, corrigenda. Memoirs of the Queensland Museum 47(1): 409-410. Brisbane. ISSN 0079-8835. The following are corrections to typographical and other errors detected in the preceding 3 parts of the Australian Ascidiacea and its supplements (Kott 1985, 1990a,b and 1992a,b). PART 1 PHLEBOBRANCHIA AND STOLIDO- BRANCHIA (Kott, 1985) p. 25 column 2, key couplet 1, 10 to read: 11 p. 37 column 1, line 7 in NEW RECORDS delete: GH2495 p. 39 column 2, line 6, somtimes to read: sometimes p. 43 column 1, line 3 in NEW RECORDS, GH2518 — 22 to read: GH2518-20 GH2522 p. 61 column 1, synonymy of Phallusia arabica to read: Phallusia arabica Savigny, 1816, p.164, Hartmeyer, 1915b, p.414. Michaelsen, 1919, p.113. ? Ascidia depressiuscula Heller, 1878, p.5. (Not Herdman, 1906, p.305 < Ascidia sp.). Phalllusia depressiuscula : Tokioka, 1970, p.87. Phallusia julinea: Tokioka, 1952: 107 (part, specimen with anal lobules). Phallusia philippinensis Millar, 1975, p.273 (part, not specimens from Singapore, see Phallusia millari sp. nov.). p. 61 column 1, lines 1- 2 in PREVIOUSLY RECORDED, delete: Queensland (Northwest 1 — Kott, 1966). p. 66 column 2, line 4 in synonymy, philippensis to read: philippinensis; line 7, in NEW RECORDS, GH2494-69 to read: GH2494-7; last line, GH2495-9 GH2502-3 to read: GH2498-9 GH2503 p. 76 column 1, line 1 in synonymy, 1900, p.76 to read: 1900, p.6 p. 80 column 1, line 2 in PREVIOUSLY RECORDED to read: holotype AM U3952, paratypes QM G4907 G4936... p. 83 column 2, 4" last line in paragraph 3, northern-eastern to read: north-eastern p. 85 column 1, line 6 in synonymy, pellucidas to read: pellucidus p. 85 column 2, line 1, Rhodosoma to read: Pera p. 86 caption Fig. 34, Rhodosoma turcica to read: Rhodosoma turcicum p. 111 column 1, last line paragraph 3, very to read: vary p. 112 column 2, Styela canopus Savigny, 1816 to read: Styela canopus (Savigny, 1816) p. 112 column 2, lines 1-4 in synonymy to read: Cynthia canopus Savigny, 1816, pp. 45,154. Stvela canopus: Herdman, 1891, p. 581. Michaelsen, 1898, p. 367 (f typica); 1919, p.66. Kott, 1957, p.144. Millar, 1975, p.304. Kott & Goodbody, 1982, p.534. p. 122 column 2, line 12 in synonymy, after Cnemidocarpa irma insert: Hartmeyer, 1927: 168. p. 141 column], linel last paragraph and column 2, lines 2, 7 and10 in first paragraph, exiqua to read: exigua Van Name, 1918, p.116, p. 177 column 2, in synonymy, Styela cryptocarpa: Sluiter to read: Styela cryptocarpa Sluiter Kott, P. 2001 xx xx: The Australian Ascidiacea part 4, Aplousobranchia (3), Didemnidae. Memoirs of the Queensland Museum xx(x): 1-xxx. Brisbane. ISSN 0079-8835p. 201 column 2, branchial formulae in paragraph 2 to read: DL 0(8) 2(9) 2(8) 2(9) 2E(WAM 794.83); E2(3) 3(6) 3(8) 2(5) 3 DL (ZMA TU976.32). p. 210 column 2, Monandrocarpa plana (Kott, 1972) to read: Monandrocarpa plana Kott, 1972 p. 210 column 2, between lines 1 and 2 in synonymy, insert: Cnemidocarpa incubita Tokioka, 1967, p.186 p. 214 column 1, line 28 Herdman, 1898 to read: Herdman, 1891 p. 215 column |, line 5 from bottom, Mand to read: and p. 217 column 1, line 3 in NEW RECORDS and line 14 in EXTERNAL APPEARANCE, QM G9484 to read: QM GH2223 p. 217 column 2, last line paragraph 3, after specimens insert: QM G2223; line 4 from bottom, Polycarpa to read: Polyandrocarpa p. 222 column 2, lines 7 to 9, delete: more ....... interspace) p. 226 Fig. 107 Scales, a, 2.5mm to read: a, 4.0mm p. 231 column 1, line 3, to read: Type Species: Stolonica socialis Hartmeyer, 1903 p. 274 column 1, line 23, 391 to read; 381 p.274 column 1, in NEW RECORDS, line 8, GH11929 to read: G11929; line 10, GH43—4 to read: GH44 p. 278 column 1, in NEW RECORDS line 10, G10157 to read: G10167; line 14, GH42-3 to read: GH43 p. 279 column 1, lines 3 and 5, violaceum to read: violaceus p. 338 column 1, in Rhabdocynthia pallida, Sluiter 1898a to read: Sluiter 1898b p. 342 column 1, in synonymy of Halocynthia hispida, Cynthia dumosa Stimpson, 1885b to read: Cynthia dumosa Stimpson, 1855b Note: according to Kott (1998), Halocynthia hispida (Herdman, 1881) is a junior synonym of Halocynthia dumosa (Stimpson, 1855) p. 344 column 1, Halocynthia papillosa (Linnaeus, 1767) to read: Halocynthia papillosa (Gunnerus, 1765) p. 344 column 1, line 8 in synonymy, Michaelsen, 1918, p. 10 to read : Michaelsen 1919, p.12 p. 356 column 1, lines 1-2 in second paragraph, the type species of M. propingquus and M. polymorphus to read: the holotype of M. propinquus and specimen of M. polymorphus: Herdman, 1882 410 p. 363 column 1, Hartmeyeria formosa (Herdman, 1899) to read: Hartmeyeria formosa (Herdman, 1882) p. 367 column 2, last line to read: not laterally flattened.......... M. ficus ; p. 371 column 2, line 8 in paragraph 5, itsovary to read: its ovary PART 2 APLOUSOBRANCHIA 1 (Kott, 1990a) p. 26 column 2, line 10 in synonymy, Sluiter, 1904, p.3 to read: Sluiter, 1904, p.24 p. 57 column 2, line 3 in NEW RECORDS, after E1973-4 insert: E2471 p. 109 column 2, Genus Distaplia line 3 to read: Type species: Distaplia magnilarva Della Valle, 1881 p. 118 column 1, line 2 in TYPE LOCALITY, Bryon to read: Byron p. 129 column 2, line 3 in TYPE LOCALITY, GH4179 to read: QM GH4179 p. 133 column 2, Genus Hypsistozoa Brewin, 1956b to read: Genus Hypsistozoa, Brewin, 1953 p. 167 column 2, line 5, delete: GH4187-8 p. 177 column 1, line 6 in NEW RECORDS, delete: G10010 p. 184 column 1, line 3 in NEW RECORDS, GH2143 to read: GH2142 p. 193 column 1, Key couplet 14, dentritic to read: dendritic p. 220 column 1, line 2 in NEW RECORDS, delete: G11941 p. 231 column 1 line 4 in TYPE LOCALITY G11942 4 to read: G11942-3 p. Pl. 13a, GH4188 to read: GH4308 PART 3 APLOUSOBRANCHIA 2 (Kott, 1992a) p. 450 column 1, line 3 in NEW RECORDS, E2531 to read: E2550 p. 463 column 1, line 6 in synonymy, Polyclinum pute: Monniot to read: Polyclinum pute Monniot p. 475 column 1, line 15 from bottom, 13 to read: 12 p. 490 column 2, Synoicum galei sp. nov. to read: Synoicum galei Michaelsen, 1930 MEMOIRS OF THE QUEENSLAND MUSEUM p. 498 column 1, in synonymy, Psammaplidium prunum Herdman, 1899, p.84 to read: Polyclinum prunum Herdman, 1899, p.83 p. 511 column 2, last line, ....... 26 to read: ....... 28 p. 567 column 1, lines 3-5 in DISTRIBUTION, delete: South Australia......SAM E2594) p. 567 column 2, line 6 in PREVIOUSLY RECORDED, Phillipines to read: Philippines p. 569 column 1, second last line in second paragraph, betwen to read: between p. 570 column 2, line 5 in NEW RECORDS, SAM E2540 E2571 E2587 to read: SAM E2540 (also registered as E2587) E2571 p. 574 column 2, last line in TYPE LOCALITY, E10648 to read: E2648 p. 595 Pl.1b, has been cropped at the wrong end, and only the ends of 3 lamellae of the colony of Condominium areolatum remain in the top left corner. p. 620 Tylobranchia to read: Tylobranchion SUPPLEMENT 2 (Kott, 1992b) All odd pages 623—655, running heading The Australian Ascidiacea 2. Supplement to read: The Australian Ascidiacea Supplement 2. p. 625 column 1, line 2 in DISTRIBUTION, delete: E2471 p. 628 column 1, lines 4-5 in TYPE LOCALITY, delete: paratype SAM E2422 p. 635 column 1, line 3 in synonymy, 1987a, p.3 to read: 1987a, p. 28 p. 635 column 2, line 3 in synonymy, 1987a, p.5 to read: 1987a, p.25 p. 648 column 1, last line in paragraph 4, objective to read: subjective p. 649 column 1, line 17 in synonymy, Moniot 1991 to read: Monniot, 1990; line 4 in DESCRIPTION, paricles to read: particles p. 650 column 1, line 3 in synonymy, 1905a, p.135 to read: 1905a, p.326 p. 652 column 1, last line in paragraph 8, 205-239 to read: 239-289 KOTT, P. KOTT, P. CONTENTS The Australian Ascidiacea part 4, Aplousobranchia (3), Didemnidae ..................00005 1 The Australian Ascidiacea parts 1-3, corrigenda