MEMOIRS

OF THE

QUEENSLAND MUSEUM

BRISBANE VOLUME 29
7 JULY, 1990 PART 1

THE AUSTRALIAN ASCIDIACEA
PART 2, APLOUSOBRANCHIA (1)

Patricia Kort

Kott, P. 1990 6 30: The Australian Ascidiacea Part 2, Aplousobranchia (1). Memoirs of
the Queensland Museum 29(1); 1-266. Brisbane. ISSN 0079-8835.

In the primarily colonial suborder Aplousobranchia of the class Ascidiacea (subphylum
Tunicata) 106 species in 20 genera in the known family group taxa Cionidae, Diazonidae,
Clavelinidae, Holozoidae and Polycitoridae, and the new families Pycnoclavellidae and
Stomozoidae are now known to occur in Australian waters, Forty-nine species and S genera
are also new. Familial and generic (including larval) characters are reviewed and revised;
and dichotomous keys are presented for all taxa.

Most of the families are diverse and well represented in Australia. Their phylogenetic
relationships and those of some of the genera discussed in this part are obscure. In some
cases (e.g. Sigillina) evidence from larval adhesive organs conflicts with relationships deduced
from adult morphology. There is, moreover, a degree of parallel evolution and convergence
in zooid and colony form (apparently directly related to the development of cloacal systems)
that often obscures phylogeny. Even in the one genus, Eudistoma, which is especially well
represented in Australian waters, there is a range of species that reflect most of the stages
in the evolution of colonial systems and colony integration, from independently opening zooids
to the presence of cloacal cavities and apertures. The anterior diversion of the first row of
stigmata along the mid-dorsal line in Pycnoclavella and in Eudistoma and other polycitorids
is another convergent character associated with size reduction and simplification of zooids.
It cannot be regarded as a significant character at higher taxon level.

However, the position and shape of the stomach and the length of the oesophagus and
duodenum are newly recognised plesiomorphic characters contributing to the definition of
a number of genera, as do the arrangement and course of longitudinal body muscles. The
site where fertilisation takes place is found to be of significance in defining Pycnoclavellidae
but is unexpectedly variable in certain genera of the Polycitoridae.

The geographic affinities of the majority of known species appear to be with tropical rather
than subantarctic fauna. Indigenous species are most common in the temperate waters of
the southern coast of the continent although there are also some tropical species that appear
to be indigenous. 0 Indo-West Pacific, Ascidiacea, Aplousobranchia, Cionidae, Diazonidae,
Clavelinidae, Pycnoclavellidae, Holozoidae, Polycitoridae.

Patricia Koti, Queensland Museum, PO Box 300, South Brisbane, Queensland, 410], Australia;
28 June 1989,

Frontispiece: a juvenile vegetative zooid of the aplousobranch ascidian Sveozva pulehra, showing the posterior
gut loop characteristic of the suborder. Branchial tentacles can be seen just inside the incurrent aperture at
the top of the pharynx. Two pairs ol rows of stigmata perforate the pharynx. and the bilabiate anus opens
into the atnal cavity near the rim of the large excurrent aperture. Incipent male follicles can be seen in the
gut loop, just behind the oval stomach.

THE AUSTRALIAN ASCIDIACEA 2

Introduction, 4
Acknowledgements, 5
Collection and Examination of
Aplousobranch Ascidians, 6
Annotated Glossary, 7

APLOUSOBRANCHIA, 18

CIONIDAE, 20
Ciona, 21
C. intestinalis, 21

DIAZONIDAE, 24
Rhopalaea, 25

R. crassa, 26

R. tenuis, 29
Pseudodiazona, 30

P. claviformis, 31

CLAVELINIDAE, 33
Clavelina, 35
C. arafurensis, 38
C. australis, 39
C. baudinensis, 41
C. cylindrica, 42
C. dagysa, 45
C. fecunda, 47
. meridionalis, 48
. mirabilis, 50
moluccensis, 51
. nigra n.sp., 53
. oliva n.sp., 55
. ostrearium, 57
. pseudobaudinensis, 58
C. robusta n.sp., 61
Nephtheis, 63
N. fascicularis, 63

AANAANAAN

PYCNOCLAVELLIDAE n.fam., 66
Pyncnoclavella, 67
. arenosa, 69
. aurantia n.sp., 71
. detorta, 71
. diminuta, 73
. elongata n.sp., 76
. tabella n.sp., 77
Euclavella n.gen., 79
E. claviformis, 79

~wRDDT

Hovozoipae_, 81
Sigillina, 84
S. australis, 87

CONTENTS

S. cyanea, 89
S. fantasiana, 92
S. grandissima n.sp., 93
S. mjobergi, 96
S. nigra, 98
S. signifera, 100
Polydistoma n.gen., 101
P. fungiforme n.sp., 102
P. longitube, 104
Hypodistoma, 105
H. deerratum, 106
H. mirabile, 108
Distaplia, 109
D. australiensis, 113
. cuscina n.sp., 115
. dubia, 116
florida n.sp., 118
muriella n.sp., 119
pallida n.sp., 121
prolifera n.sp., 122
racemosa n.sp., 124
regina n.sp., 125
. retinaculata n.sp., 125
. stylifera, 127
. tokioka n.sp., 129
. violetta n.sp., 130
. viridis, 132
Hypsistozoa, 133
H. distomoides, 134
Neodistoma n.gen., 135
N. mammillatum n.sp., 135
Sycozoa, 137
. brevicauda n.sp., 140
. cavernosa n.sp., 142
. cerebriformis, 143
. murrayi, 146
. pedunculata, 147
. pulchra, 149
. seiziwadae, 152
. sigillinoides, 153

bSSSSSHSOSHSDH

RAKNRARHRHHYNH

STOMOZOIDAE n.fam., 156
Stomozoa 157

S. australiensis n.sp., 157

S. bellissima n.sp., 159

POLYCITORIDAE, 162
Polycitor, 165
. annulus n.sp., 165
. calamus n.sp., 167
. cerasus n.sp., 168
. circes, 169

~ D7

4 MEMOIRS OF THE QUEENSLAND MUSEUM

P. emergens n.sp., 170

P. giganteus, 171

P. nubilus o,sp,. 174

P. obeliscus, \75

P. subarborensis, \75

P. translucidus, 176
Cysrodytes, 178

C. dellachiajei, 179
Palyeitorella, 183

P. voranaria, 184

P. orientalis n.sp., 187
Fudistoma, 188

E. amplum, \94
. anaemaium n.sp., 196
| angelanum n.sp., 197
. aureum n.sp., 199
. hulhatum n.sp., 200
. carnosum n.sp., 201
constrictum n.sp., 203
eboreum n.sp., 205
. elongatum, 205
. gilboviride, 206

Bb mh mma

The following account (part 2 of a review of the
Australian ascidians) treats species of the families
Cionidae Lahille, 1887, Diazonidae Seeliger, 1906,
Clavelinidae Forbes and Hanley, 1848, Holozoi-
dae Berrill, 1950. Polycitoridae Michaelsen, 1904,
und the new families Stomozoidae and Pycnoc-
lavellidae. These families, together with Polycli-
nidae Milne Edwards, 1842 and Didemnidae
Giard, 1872 (yet to be treated), comprise the 9
presently recognised familics of the suborder
Aplousobranchia Lahille, 1887. It is one of the
two suborders in the order Enterogona, the other
being the Phlebobranchia.

The classification and phylogeny of the
suborders Phlebobranchia and Stolidobranchia
(the only suborder of the order Pleurogona) are
reviewed and revised in part | of this work (Kott
1985), which also includes accounts of the species
of these taxa that occur in Australian waters,
guides to their identification and a discussion of
their biogeography.

In the following account of the Aplousobran-
chia, aspects of larval as well as adult morphology
have been invoked to determine phylogenetic

glaucum, 208
globosum, 210
gracilum n.sp., 211
incubitum n.sp.. 212
laysani, 214
maculosum n.sp,, 216
malum n.sp., 217
microlarvum w.sp., 218
muscosum nom, noy., 220
ovatum, 222
pratulum nsp.. 224
purpureum n.sp., 225
pyriforme, 226
reginum n.sp., 228
sabulosum n.sp. 229
superlatum n.sp,, 229
tigrum n.sp., 231

E. tumidum n.sp., 232
Exostoma n.gen., 233

E. ianthinum, 234
Brevicolluy n.gen., 236

B. tuberatus n.sp,, 237

affinities, Definition of polyphyletic assemblages
such as the Clavelinidae and Polycitoridae have
been adjusted in order to arrive at monophyletic
groupings wherever possible.

Aplousobranch families are separated from one
another primarily on the basis of their respective
replicative processes, supported by aspects of
colony, zooid and larval morphology. Accord-
ingly, the new family, Pycnoclavellidae is erected
to accommodate genera formerly included in the
Clavelinidae, In many taxa the replicative process
is not known and, as for the new family
Stomozoidae, it has been deduced on the basis
of colony and adult morphology. Sometimes
evidence from larvae conflicts with a phylogeny
based on these deductions. In particular there is
uncertainty regarding the family affinities of
Sigillina, Hypadistoma and Polydistoma n.gen.;
Sigillina mjahergi, and Cystodyres, Polyciterella,
and the new genus Brevicollus.

As in Part 1, the following account of aplou-
sobranch families is based on the collections of
all Australian and some American and European
museums. It includes many thousands of newly

THE AUSTRALIAN ASCIDIACEA 2 a)

recorded specimens recently collected by the
author and her colleagues. The general morphal-
ogy of colony, zooid and, in most cases, the larvae
have been examined and recorded. The histology
of these organisms has not been considered in this
work

All specimens for which the registration number
is cited have been examined in connection with
the present work. Where a colony is registered
in 2 institutions, the second mumber (in italics)
refers tO a sample part only

Abbreviations used to indicate the institution
in-winch specimens are lodged are as follows: AM,
Australian Museum, Sydney, New South Wales:
BM, British Museum (Natural History), London,
UK; MHN, Museum Nationale d’Histoire Natu-
felle. Paris, France; OM. Otago Museum,
Dunedin, New Zealand; QM, Queensland
Museum, Brisbane, Queensland, SAM, South
Australian Museum, Adelaide, South Australia;
TM, Tasmanian Museum, Hobart, Tasmania:
MY, Museum of Victoria, Melbourne, Victoria;
NTM, Northern Territory Museum, Darwin,
Northern Territory, WAM, Western Australian
Museum, Perth, Western Australia; USNM, US
National Museum of Natural History, Smithson-
ian Institution, Washington DC, USA: ZMA.
Zoological Muscum of Amsterdam, Anrsterdam.
Netherlands: ZMC, Zoological Museum Copen-
hagen, Copenhagen, Denmark.

ACKNOWLEDGEMENTS

The many colleagues who have encouraged my
studies of the Ascidiacea from 1949 are referred
to in Part | (Kott 1985). Emeritus Professor C.
Burdon-Jones deserves special thanks tor his
ongoing support and practical assistance with this
part of the project. Dr Robin Millar formerly of
the Scottish Marine Biological Association, Oban,
Scotland also continues with his encourageroent
and interest. The Queensland Museum Board
through the Director, Dr Alan Bartholomai,
continues to give its support to this project.
Much of the newly recorded material was taken
in the course of major surveys of the fauna of
the Australian continental shelf including the
North West Shelf.and Kendrew Islands (Dr Barry
Wilson, Ms. Shirely Slacksmith and Ms Loisette
Marsh of the Western Australian Museum,
supported by Australian Marine Science and
Technologies and Crown of Thorns Commitlee
grants); the Great Australian Bight, and Spencer
and St Vincent Gulfs (Mr Scoresby Shepherd, Mr
Nigel Holmes and other colleagues of the South
Australian Fisheries Department, supported by

the South Auserahayn Museum and Australian
Marine Science and Techyologics grants |)
conection WIth sea grass productivity and. uther
programmes); Bass Strait and the Victorian coast
(Museum ol Victoria supported by an Australian
Marine Science and Technologies grants, the
Western Port Survey, and various surveys
conducted by Mrs J, Watson of Marine Science
and Ecology. Victoria), the Great Barrier Reef and
the Queensland coast (the north-eastern fishers
survey conducted by Dr G. Goeden of the
Queensland State Fisheries Department and Dr
Lester Cannon of the Queensland Museum, and
the Cleveland Bay survey by Mr Alistair Birtles
and Dr Peter Arnold of James Cook University
of North Queensland, both supported by Austral-
ian Marine Science and Technologies grants, the
Abbot Point survey conducted by Professor Cyn
Burdon-Jones of James Cook University of North
Queensland ‘for Mt Isa Mines, and material
collected by Mr E, Lovell while engaged in coral
collecting programmes for the Australian Institute
of Marine Science),

The author’s own collecting has becn supported
by grants from the Australian Research Grants
Committee (D65/ 15386 1969-71, H64) 15386
1975). the Australian Biological Resources Survey
(1980-42); and the Australian Marine Science and
Technologies Grants Scheme (MST 83/1920 te
C, Hawkins and P. Mather), Ms Lucille Creyola-
Gillespie and Mr Stephen Cook have been able
and conscientious assistants both in the Geld and
in the laboratory. Or David Parry and Mr Andrew
Rovefelds have also helped in the field. Stephen
Cook drew most of the black and white figures
fram the authors $ketches, Mrs Petit Woodgate
typed the many thousands of words that were
involved in the preparation of this manuscript fie
publication, from first draft to its final stage

Muscum curators who have contributed to the
progress ol the present study hy their prompt
attention to requests for loans of cousiderable
parts of their collection are Ms L. Marsh (Western
Australian Museum), Mr W. Zeidler (South
Australian Museum), Ms 8. Boyd (Museum of
Victoria}, Dr. F, Rowe (Australian Museum), Mr
G. Anderson (British Museunt, Natoral History).
Dr E. Rasmussen (University Zoological Museum,
Copenhagen), and Dr A. Pierrot Bults (Zoological
Museum of Amsterdam), 1 am grateful to thern
all, Perhaps oy greatest indebtedness is to those
photographers (both prolessional and amatetr|
who provided images of the living organisms (1
situ, and who have allowed me to use those images
to illustrate these Volumes, They include Graham
Edgar (whose photographs of Asetdia challengeri.

6 MEMOIRS OF THE QUEENSLAND MUSEUM

A, sydneiensis and Botrylloides magnicoecus from
Port Davey in Part | of this work were wrongly
attributed), Paul Fredrickson, Rudy Kuiter, Roger
Lethbridge, Ed Lovell, Dave Parry, Ron and
Valerie Taylor, Gary Russ, W.H. Sasse, and
Jeanette Watson. Most particularly | am grateful
to Neville Coleman, Scoresby Shepherd and Nigel
Holmes whose careful indexation of image to the
actual preserved specimen has remoyed the
possibility of error that occurs when identification
based only on photographs is attempted.

COLLECTION AND EXAMINATION OF
APLOUSOBRANCH ASCIDIANS

Generally species of the suborder Aplousobran-
chia are more difficult to collect and preserve than
are phlebobranch or stolidobranch species. There
are several reasons:

1. the test that surrounds the zooids, or in which
they are embedded is relatively soft, and this
together with the large cloacal spaces (when
they are present) make colonies vulnerable to
damage and distortion.

. Possibly because the test is relatively soft and
lacks the fibrous, leathery properties of most
stolidobranch species, it does not usually
adhere firmly by a small part of the surface,
or form tough rooting systems. Thus colonies
are seldom upright and more often they grow
two-dimensionally, over flat, hard substrates
to which extensive areas of basal surface or
extensive stolon systems form such firm
attachments that colonies are difficult to
remove. In these cases the colony, lacking other
skeletal elements, has the advantage of the
substrate to support it. Exceptions are in genera
where species are sometimes (Sigi/lina), or
always (Sycozoa) stalked. In the latter genus
the stalk often is long and leathery.

3. Zooids are invariably small and usually
muscular. They need careful narcotisation to
ensure that their structure is not obscured by
contraction.

Thus the collection of aplousobranch ascidians
by dredge results in the sampling of large, firm
colonies, such as Polycitor giganteus. However the
great majority of taxa with delicate test, including
those with separate zooids (Diazonidae, Claveli-
nidae, Pycnoclavellidae) or taxa with small or flat
and two dimensional colonies (Eudistoma) are not
adequately sampled.

On the other hand, although most aplouso-
branch ascidians occupy cryptic habitats, their
bright colours (which usually are not hidden by
the ephiphytes or adhering foreign particles that
occur in Stolidobranchia) are conspicuous, and

bo

have attracted the attention of SCUBA divers. In
the past twenty years, collections by hand, using
SCUBA equipment has demonstrated a diversity
in the Australian aplousobranch fauna that
formerly was not recognised.

Where possible, to avoid damage, specimens
should be removed from the substrate. However,
occasionally, the whole or part of the substrate
with its adhering ascidians can be collected.
Sometimes because of the size of the colony, or
the strength of its adhesion, it will be possible
to sample only a part. In this case the size of
the whole colony and the part of it represented
by the sample should be recorded.

As well as physical damage and contraction of
the specimens the study and identification of
ascidians is made difficult by the loss and rapid
oxidation of pigments, following their collection,
fixation and preservation. Colour notes should be
made and colour photographs of the living
specimen (carefully indexed to the specimen)
should be taken if possible. Notes should also be
taken on the arrangement of zooids in living
colonies for in preserved material this also is
obscured by colour changes, and contraction.

Since most aplousobranch ascidians generate
acid on lysis of the test cells (Parry 1984, 1987),
specimens should be thoroughly washed in
seawater after removal from the substrate.

Menthol crystals are an appropriate narcotising
agent for ascidians. More rapid relaxation is
achieved by using a very weak solution of MS222
(Sandoz Ltd.). A few grains of powder in Sml
seawater was made up as a stock solution. About
2 drops of this solution per 100ml of sea water
was found to relax most species rapidly and
completely.

When examining colonies with embedded
zooids, their morphology, and orientation and
arrangement in the colony can be observed in thin
inspection slices or wedges cut through the whole
radius of a cloacal system or colony lobe, from
the cloacal aperture or centre of the lobe to the
outer margin, parallel to the long axis of the zooids
through whole depth of the colony. To examine
them more closely and for dissection, the zooids
themselves are often removed more easily from
these inspection slices than by any other method
of pulling them from the colony, Very small zooids
can be examined and dissected in adrop of glycerol
on a microscope slide. Sometimes they need to
be stained before this is done. Most taxa of the
suborder Aplousobranchia are viviparous and
embryos are found incubating in the colony. These
can be examined by staining, clearing and
mounting whole.

THE AUSTRALIAN ASCIDIJACEA 2 7

Fic. 1, Ascidian morphology (diagrammatic): A, stalked,
solitary individual divided into thorax (a-m) and
abdomen (m-u); B. gut Joop, showing subdivisions.
associated organs, descending (proximal) limb (m-
u) and ascending limb (u-e). Symbols: a, branchial
aperture; b. atrial aperture; c, neural complex: d.
branchial tentacles: e, anus; f, rectum: fy, rectal valve;
g, endostyle: h. sligmatum, i, internal longitudinal
vessel) j, atrial cavity; k, parietal body wall; 1, test:

ANNOTATED GLOSSARY

The morphology of aplousobranch ascidians (Figs
1,2) is discussed, and the terms and conventions
used in this work are defined below, The
morphology of the Ascidiacea has been reviewed
by Berrill (1950). Goodbody (1974) has reviewed
the physiology and Millar (1971) the biology of
the group. The annotated glossary in Rott (1985)
should be used in conjunction with the following
entries:

m, oesophageal opening; n, oesophagus; na. préestom-
ach (found only (n some Claveling spp.); 0, vas
deferens; p, stomach; pa, gastro-intestinal duct: pb.
gastric vesicle; pe, Lubules of gastrointestinal (pyloric)
gland; q, gastric suture line; r, intestine; rd, duodenal
region of gut; ri, mid-intestine; rp, posterior stomach;
8, ovary; t testis; wu. pole of the gut loop, v, vascular
stolon: w, test vessels; x, terminal ampullac.

adhesive organs; epidermal structures at the
anterior end of the larval trunk. Larger laryae
have 3 in a triradial arrangement, but in the
small larvae of the Polycitoridae, Polyclinidae,
and Didemnidue they are in a median vertical
row, Occasionally there are only 2 adhesive
organs (Pyenoclavella spp., Sigillina spp.,
Euherdmania spp.). In some Didemnidae (e.g.
PDiplosema multipapillata Kott, 1980) and
Polyclinidae (e.g. Aplidium triggiensis Kott,

MEMOIRS OF THE QUEENSLAND MUSEUM

1963, 1976) the presence of more than 3 adhesive
organs is probably an adaptive response 10
environmental pressures, The most simple
organs dre non-everting conical ones found in
the small larvae of Ciona, the Diazonidac, and
solitary phlebobranch and stolidobranch
asculians which, with the exception of a few

Poly, arpa spp. (see Kott 1985) and some

Molvula spp., are all oviparous. With the

exception of the Diazonidae, colonial species

of all suborders have viviparous larvae with
more vomplex everting adhesive organs,

Cloney (1977). in the only study on the fine
structure of the adhesive organs of ascidians,
investigated the adhesive organs of Distaplia
accidentaliy Bancroft and Diplosama maede-
naldi, They are entirely ectodermal in both
species, and are essentially the same, consisting
of an axial cone !rom the centre of a cup-shaped
protrusion at the end of a stalk. The larval
haemocoelic cavity continues up into the walls
of the cup separating its outer (marginal) wall
from the inner (parietal) wall, The cup rim has
myoepithelial cells (which contract during the
eversion of the axial cone) and anchor cells
which hold the larval test firmly in place against
the ectodermal epithelium, The parietal wall of
ihe cup and outer wall of the axial cone contains
secretory cells (collocytes) which produce
adhesive material. The core of the axial cone
contains columnar epithelial cells which extend
the whole length of the cone and haye apical
processes extending into a terminal hyaline cap
that protrudes through an opening in the larval
test and forms the initial attachment to the
substrate. Subsequently adhesive material is
released from the secretory cells of the surface
of the axial cone which is extruded through the
test. The eversion of the axial cone and the
attachment of the larva to the substrate is a
complex process also involving fibrous lamellae
from the coneavity of the adhesive organ,
between the axial cone and the panetal wall
of the surrounding cup (see Cloney 1977),

In Aplousobranchia, there are (at least) 5
basic types of everting adhesive organs.
including the simple axial cones described by
Cloney (1977) viz:

1. Invaginated Lubes in Pycnoclavellidue,
Euherdmania, and Sigillina mjobergi,

2. Simple axial cones composed of central
columnar and penpheral cells in the centre
of epidermal cups in which the haemocoel
protrudes between panetal and marginal
layers of cells, as described by Cloncy (/oe,
cit). These appear similar in Clavelinidae,

Stomozoidae nam., Speozaa, Distaplia,
Mlupsistezoa, Palycitor, Eudistoma, Cysto-
dpres, Polycitorella, Polyclinidae and
Didemnidae, Adhesive organs of this type
have Stalks of various lengths, from short
und thick (in Clavelinidae and Holozaidae)
to long and narrow (in some Polveitoridae,
and in Polyclinidae and Didemnidae). The
axial cones are shallow and sessile in wide
ectodermal cups in Clavelinidae and Stumo-
eoidae; conical and constricted around their
base in deep ectodermal cups in Distaplia,
Syeezwa and related genera in the Holozoi-
dee, and in Cystodytes and Polyeiror
(Polycitoridae), wide, flat-topped and
mushroom-shaped with a pronounced con-
striction around the base and shallow
ectodermal cups in Eudistoma and Palyci-
torella (Polycitoridae).

3. Complex flat-topped axial platharms and
ridges composed of arborescent groups of
columnar cells that resemble those of
Eugistoma to some extent, but are larger and
are depressed into the ectoderm (rather than
stalked). These oceur in Sigil/ina and
Mvpodistoma. It is possible that they will
be found also in Po/ydisioma n.gen,

4. Cloney (1977) refers to a thick-walled axial
vesicle filled with adhesive in larvae of
Eudistoma river’ Van Name and £. molle
Ritter (see Van Name 1945). Adhesive organs
of species of Polycitor, Eudistoma and
Exostoma ti.gen. inthe present collection are
stalked, and have flat-topped, rather (han
conical, axial protrusions with the usual
columnar and peripheral cells (see 2., above).

5. The tulip-shaped sessile adhesive organs of
Brevicollus tuiberatus appear another type.
Their long, double-layered walls may be the
homologue of the ectoderm cup of other
forms, but they do not contain an axial
protrusion of any sort, and the deep elliptical
concavity has apparently filamentous lamel-
lac resembling those in the sulcus between
the parietal wall of the cup and the axial
cone of Distaplia (Cloney 1977), The
relationship of these with other adhesive
organs 1S not apparent,

apertures: The incurrent (or branchial) aperture

and the excurrent (or atrial) aperture are the
(Wo Openings of the ascidian body. The rim of
the branchial aperture is divided into 6 lobes
in most aplousobranch taxa except in the
Clavelinidae and Pyenoclavellidae (in Which i
is smooth) and in Speozea (in which the lobes

THE AUSTRALIAN ASCIDIACEA 2 9

are much reduced), The incurrent stream of
water, generated by the cilia lining the pharyn-
geal perforations (stigmata), enters the bran-
chial sac through the branchial aperture, which
always opens directly to the exterior. The
excurrent water that has been strained through
the branchial wall. together with faeces and
reproductive products expelled into the atrial
cuvily, leave the zooid through the excurrent
(or atrial aperture). This opens directly to the
exterior in the Diazonidae. Clavelinidae,
Pycnoclavellidae, Sigi/lina, Polyeistoman. gen.,
Stomozoidae. Polycitoridae (with the exception
of Exastoma), aud Euherdmaniinae, The
excurrent water is expelled indirectly, through
a cloacal cavity with a limited number of
openings to the exterior, in Holozoidae (with
the exception of Sigillina and Polydistoma
n.gen.), Exostoma n.gen., Polyclinmae and
Didemnidae,

In the former group of taxa the atrial aperture
is always 6-lobed but in the latter group only
Exostoma o.gen., and Hypodisroma have 6-
lobed atrial apertures. The others have an upper
lip. sometimes subdivided, which inserts into
the test around or along the sides of the cloacal
cavity or its apertures. The sides and posterior
border of the atrial apertures of these genera
usually are smoath.

The number (6) of lobes around the rims of
the apertures is relatively stable in Aplousobran-
chia. The only exceptions (as described above)
are where atrial apertures are adapted to open
into cloacal cavities, and where the rims of the
openings are smooth (Clavelinidae and Pycnoc-
lavellidae), There is less stability in this character
in ather suborders. Phicbobranchia huve 6 or
more atrial lobes and usually more branchial
lobes, Stolidobranchia basically have 4 bran-
chial and 4 atrial lobes (Styelidac, Pyuridae),
or 6 branchial and 4 atrial lobes (Molgulidae),
although modifications can occur that change
these numbers,

When zovids open separately surface features
of the test often separate incurrent and excurrent
streams of water by directing them away from
one another. or by raising cloacal apertures
ahove the branchial ones (Katt 1989),

anal opening, anus: sce gut, gut loop.
ascending limb of gut loop; see gut, gul loop.

asexual reproduction: sce cloacal systems,
colonies, epicardium,

utrial cayity; the cavity, lined by ectoderm, Tormed
(in the Enterogena) by Jason of paired

invaginalions from the dorsum to surround the
sides of the pharynx. Ciliated pharyngeal
perforations Open into this cavity. In Aplou-
sobranchia the gui loop and gonads are
posterior to the cavity and not embedded in
the parietal body wall alongside it, as they are
in Stolidobranchia and Phlebobranchia.

branchial folds; such as those found in the

Stolidobranchia, do not occur in the Aplou-
sobranchia, in which the pharyngeal wall is
always flat.

branchial papillae: papillae, vertical to the plone
of the pharyngeal wall, which support the
internal longitudinal vessels. Both occur in
Cionidae and Diazonidae. The minute papillae
on the transverse vessels of Protopalvelinum
Millar, 1960 and Polyelinum may be vestiges
of the vertical papillae. There arc no papillac
in other aplousobranch families

branchial sac: the pharynx of an ascidian,
perforated by rows of stigmata, In colonial
ascidians, as replication becomes more prolific
and szvoids became more numerous, their
progressive reduction in size and increasing
simplification ig reflected in the branchial sac.
In Aplousobranchia numerous stigmata in
many rows and internal longitudinal vessels are
present only in the Cionidae and Diazonidae,
butin other taxa the internal longitudinal vessels
art Jost and stigmata decrease in number as
zooids become smaller. Clavelinidae and
Palycitor sometimes have relatively numerous
stigmata in numerous rows but internal
longitudinal vessels are absent. The number of
stigmata per Tow remains relatively high in
Sigillina and Pyenoclavella, although the
number of rows is reduced, Sigi/lina has only
3 rows of stigmata and some Pyeneclavella spp.
have only 2 (see below). Both the number of
rows and the number of stigmata per row is
most reduced in the small zooids of Audistama,
(See also branchial papillae, internal longitud-
inal vessels).

branchial tentacles: stumpy or tapering endoder-
mal Structures, in one or more circles at the
base of the branchial stphon. In Aplousobran-
chia they are always simple without side
branches. They occur in more than one circle
in many species, wiz. in Clavelinidae und in
Auclistoma. Eudistoma may have up to 9 circles
of tentacles in a wide band at the base of the
branchial siphon.

It) MEMAQIRS OF THE QUEENSLAND MUSEUM

brooding: sce incubativa of embryos,

budding: sce replication.

cloacal cavities, — systems; arrangements of

embedded zooids around cloacal cavities in the

test, into which their atrial apertures open,

rather than opening directly to the exterior, The
branchial aperturcs maintain their separate
independent openings directly to the exterior,
The degree of integration of the colony can be
measured by the form of the systems and the
extent to which the zooids are organised into
systems. Any cloacal system indicates a fair
degree of integration,

The most rudimentary cloacal systems are
those in the Polycitoridae (fuedistoma, Palvet-
rorella and Cystadyres but not in Polyeirar) in
Which zooids are arranged in circles (Fig. 2c),
their atrial apertures toward the centre of the
circle where the excurrent streams of water
reinforce one another, Sometimes the atrial
apertures open into u depression in the centre
of the circle (Fig. 2d). This is a forerunner of
the mast simple cloacul system in which a circle
of zooids surrounds an actual cloacal cavity
which receives excurrent Water fram the wtria!
apertures which open into it. This water leayes
the colony through u cloucal aperture (some-
umes referred to as a common cloacal aperture)
in the surface fest that rools over the cavily
(Fig. 2e).

The evolution of cloacal systems includes
their extension from circles to ovals, and
subsequently to long and sometimes branching
systems of canals, which radiate away from the
cloacal aperture beneath the surtace of the
colony. In the highly integrated colonies of
Speezoa, long cloacal canals, lined on each side
with a row of 2o0ids, extend parallel to one
another down the sides of the colony. In
Didemnidae, cloacal cavities are sometimes
almost continuous Spaces that surround the
zooids, or clumps of zooids, either at thoracic
level. or extending into the lower half of the
colony to surround the whole length of the
zooids. with deep spaces (see Kott 1962). In
Atrivdum and Leptoclinidey (Didermidae),.
Mypadisroma (Holozoidae) and Exostonia
i.gen. (Polycitoridae), long, posteriorly
oriented, atrial siphons from the postero-dorsal
part of the thorax carry eXcurrent Water to
cloacal spaces and canals at abdominal or even
posterior abdominal level

Holuzoidae have a great range in the
development of systems, In Sigi/lina the atrial
aperture of each zooid opens separately to the

exterior, bul most species have a degree ol
integration in the colony. Usually they have a
basal stalk and a terminal head with the yooids
opening around the head and all facing the same
way. Their endostyles (ventral surlaces) are
below the dorsal surfaces, the branchial
apertures face down towaed the slulk, und Lhe
atrial apertures are directed upwards, toward
the top of the colony (see Kott 1989). Thus,
although the -olony could be said to comprise
a colonial system, clogeal systems are not
formed, Similarly the new genus Palveixionia,
with branchial apertures on the undersurface
of the fronds of the colony and the atrial
apertures uppermost, cun be said to have
colonial, but not cloacal, systems. Similar
systems dre present in certain genera ol the
Euherdmaniinae (viz. Ripere/la),

In the Polyelininae (Polyelinidae), most
species of the Didemnidae, the holozoid genera
Neodistoma o.gen, and Hypadistema, and the
polycitorid Awestonta n.gen., the cloacal
systems are extensive, and involve large
numbers of sinall zooids. The shape and size
of these cloacal systems and the colonies
themselves Jack the regularity of those in
Distaplia and Sycozed, being more affected by
environmental factors and age.

In Distaplia and Syvazoa the disposition of
zoolds is ordered, cloacal systems are regular
in sve and shape, and are systematically
arranged in the colony, replication is prolific,
and gamete production is synchronised. {t 1s
probable that Speozod spp., with certain
didemnid species, represent the most highly
integrated colomes in the Ascidiacea, In
stolidobranch uscidians, cloacal systems occur
only in Botryllinac. Sometimes they are
comparable with the extensive branching
systems found in Polyclininae, Only occasion-
ally (BotryHoides magnicoecus) do they achieve
the degree of integration that occurs in the
Speosaa and in most Distaplia spp.

colonial systems: an ordered rather than random
arrangement of Zooids in the colony, Colonial
systems include cloacal systems (see above), In
many species of Clavelinidae, Pycnoclavellidac.
Sigillina spp., Polydisioma, Stomozoidue,
Polycitoridae and Euherdmuaniinae (Polyclini-
dae), however, in whieh the 4zooids maintain
their independent atrial aperture direct to the
exterior, colonial systems are formed that do
not involve a common cloaca. In these systems
zooids are regularly arranged, sometimes (but
not always) in stalked colonies. with (heir
branchial and atrial apertures co-ordinated with

THE AUSTRALIAN ASCIDIACEA 2 Il

hic. 2, Evolution of cloacal svatens (diagrammatic): a, partially embedded sooids, no kystems (Diazona, Clavelina
and Pycnnelavella): b, completely embedded acids forming colonial, but not cloacal, systems with 6-lobed
atrial siphons opening separately to the exterior (Cla velina spp... NepArhets fasetcularts. Sigillina spp., Polvdistoma
p.gen.. Stomozoa, Polychor spp., Budistoma spp.): ce. sooids arranged in circles with 6-lobed atrial siphons
opening W the centre to form incipient cloacal systems (Eudisioma spp., Polycitorella spp., -Cystadiey spp.)
d. foods with G-lobed atrial siphons opening mle rudimentary (Ludistoma spp.) to extensive (Hipodistoma
spp., Exestunta ngen,) cloacal cavities; ef. zooids lormed into well developed cloacal systems. their wide-
lipped excurrent openings often exposing their branchial sacs directly lo the Jong, sometimes branching cloweal
canals ar cavities, cach of which opens to the exterior by a single cloacal aperture, e. zooids with gonad
in the gut loop (Disyaplia, Sreazva, Didemnidae), f, zovids with ponads ina posterior abdomen (Polyeliiidac)
Symbols! eee, common clowcul cavily, the arrows show direction of current How

respect Lo enVironinental factors (such as
direction of current flow), Phere sno indication
of even a moderate degree of integration in the
colonies of other taxu in the Diazonidae,
Clavelinidac and Pyenoclavellidac in which the
Zoids, although colonial, being joined by basal
stalons, or partly (Fig. 2b) or completely
embedded, do not form systems.

colonies; With the exception of Cigna, certain
species of the Diazonidae (viz. Rhopulaea spp.),
and Clavelinidae (Clavelina dagysa, C. ostrea-
rium, C. meridionalis, C. viola, C, miniata), all
uplousobranch ascidians are colonial. The
yooids that make up the colony are produced
by replication of the oozooid (primary zooid)
usually following metamorphosis. Sometimes
replication begins in the larva, buds being
isolated from @ vegetative stolon containing an
extension of the epicardial sac in the region of
the ocsophagus (Sveozea, Distaplia and
Hypsistozoa in the Holovoidae and some
Didemnidae), although these buds do not
always persist to form definitive zooids (sce
Berrill 1950; Brewin 1956b), The various
budding processes have been summarised hy
Berrill (1935b, 1950) and Kott (1982b), Repli-
cation occurs in all aplousobranch ascidians
except Ciena and Rhopalaea. Watanabe and
Tokioka (1973) have shown how the solitary
vooids af Clavelina miniata develop from buds
that subsequently move away from the parent
zooid. Clavelina mericdionalis replicates develop
from the yascular stolons in the stalks that
persist after degeneration of the parent zooid
(see below). Regeneration of thoraces [rom the
oesophageal region of both Ciena and Rhapa-
laea may be an eurly stage in the evolution of
the replicative process and the development of
colonies in Aplousebranchia (see Katt 1982b;
see ulso colonial systems, cloacal systems and
replication),

descending limb of gut loop: see gut loop.

distal: (he end of an organ or structure toward
which the contents or products move, or which
is farthest from the base or point of Origin (see
also proximal),

dorsal lamina, — languets: pointed, triangular
projections from the transverse vessels of the
branchial sac Where they cross over the dorsal
simus, They are in a line parallel and to the
left of the dorsal mid-line in most genera of
the Aplousobranchia. A plain-edged fold of the
pharyngeal wall forming a dorsal lamina ag in
many families of Phlebobranchia and Stolido-

MEMOIRS OF THE QUEENSLAND MUSEUM

branchia does not eceyr in Aplousobranchia,
Bernll (1950) belleves that the presence of dorsal
languets is a more primitive condition than the
continuous fold.

dorsal tubercle: see neural duct.
duodenum: sce gut loop,

endocarps: thickings or fleshy outgrowths of the
parietal body wall thal occur often in Stolido-
branchia. They are not found in
Aplousobranchia.

epicardial sacs, epicardium: paired endodermal
sacs (hal evaginale from the postero-veotral part
of the pharynx, In Ciona these sacs develop
following metamorphosis (see Berril 1950). ‘The
left sac envelopes the gut and gonads, and the
right one the heart and pericardium, In Ciena
they maintain their openings into the pharynx,
one opening on each side of the mid-line in the
ventral part of the retropharyngeal groove. In
the Didemnidae, and the genus Awherdmania
(Polyclinidae), the sacs remain separate trom
one another. In the majority of other taxa they
fuse into a single epicardium which extends
along the length of the abdomen (where it is
associated with the oesophagus and stomach)
to terminate around the pericardium at the
posterior end of the abdomen (Diazonidae,
Clavelinidde, Pyenoclavellidae, Polycitoridae},
and at the end of the posterior abdomen
(Polyclinidae with the exception of Fuherdmia-
nia). In Euherdmania, as in Ciona, one af the
2 sacs is associated with the gut loop in the
abdomen, The other eXtends the length of the
posterior abdomen to terminate ground the
pericardium and heart which, in Aukerdmanic,
is in the posterior abdomen (Trason 1957).

Although in Holozoidac, the epicardial sacs
are believed to luse, there are two in Sigillina
grandissima n.sp, (see below), The lef\ sac lies
in the abdomen and, again as in Ciona, it is
this left sac Lhat terminates over the pericar-
dium. The right sac extends the length of the
vegetative stolon as is usual in the Holozoidae
where the fused epicardium extends beyond the
heart to form a narrow lumen in the vegetative
stolon, The presence of the epicardium in the
Vegetative stolon distinguishes that organ from
the large vascular stolon of (he Clavelmidae and
Pyenoclavellidae,

Tt was the presence of the epicardium in the
vegetative stolon of the Holovwidue that led
Caullery (1909) to suggest the stolon was the
homologue of the posterior abdomen in the
Polyelinidae. However these structures differ,

THE AUSTRALIAN ASCIDIACEA 2 13

not only in the absence of the gonads and heart
from the holozoid stolon, but also in the
processes by which they respectively form the
replicate zooids that are added to the colonies
(see Caullery 1909). In the Didemnidae the sacs
are much reduced in length and persist as two
small vesicles in the oesophageal region. As in
all other groups except Clavelinidae, the
epicardium in Didemnidae comprises the
regenerative tissue in the replicative process (see
Berrill 1935b, 1950).

In Phlebobranchia the embryonic epicardium
is the source of the excretory vesicles that lie
around the gut loop. In Stolidobranchia the
epicardium is probably also involved with
excretion (see Berrill 1950, and Saffo 1978 for
an account of the kidney in Molgulidae).

excurrent aperture: see apertures.

fertilisation: occurs externally in Cionidae and
Diazonidae (as in most Phlebobranchia and
Stolidobranchia). All other Aplousobranchia
are internally fertilised, either in the oviduct or
in the atrial cavity (see also incubation of
embryos).

gastric caecum: a small diverticulum of the
stomach which often is present in phlebobranch
and stolidobranch ascidians. It is present in
juvenile Ciona (see Millar 1953a) but not in
other aplousobranch taxa.

gastric folds, — ridges: parallel longitudinal
glandular swellings in the internal lining; or the
folds of the whole stomach wall. These occur
in aplousobranch taxa Ciona, Rhopalaea, some
Distaplia, and Polycitor (see Key to the genus
Polycitor, below), Stomozoidae n.fam., Euherd-
mania, Ritterella and Aplidium.

In Stolidobranchia, glandular folds occur in
Styelidae and Molgulidae and in some Pyuridae.
However, in the latter family Pyura has a
characteristic, large, branching, liver divertic-
ulum which may take the place of gastric folds.
In aplousobranch ascidians there is neither a
gastric caecum (as in Styelidae), nor a liver
diverticulum (as in the Pyuridae and Molgu-
lidae), nor any other diverticula of the stomach
wall other than the gastric folds or ridges that
occur in the few taxa referred to above.

Although it is primarily smooth, the stomach
wall sometimes is folded into 4, probably as
an artefact of its preservation, in Pseudodia-
zona, some Rhopalaea (e.g. R. tenuis), Clave-
linidae, Pycnoclavellidae and Sigillina, The
stomach wall is completely smooth in Polydis-
toma n.gen. Hypodistoma, certain Polycitor

and Distaplia, Sycozoa, Eudistoma, most
Polycitorella, Cystodytes and Exostoma n.gen.

gastric reservoir: see gastro-intestinal gland.

gastro-intestinal gland, — connective: as in

phlebobranch and stolidobranch ascidians, a
gastro-intestinal (or gastric, or pyloric) gland
is present in the Aplousobranchia. The gland
has tubules that encircle the ascending limb of
the gut loop adjacent to the stomach (which
is in the descending limb). These tubules join
into a single duct (gastro-intestinal connective:
Kott 1985) which opens into the distal end of
the stomach at its junction with the duodenum.
Sometimes the duct expands into a spherical
reservoir about halfway along its length.

The gland probably is present in all ascidians
(Berrill 1950). It is known to occur in Ciona,
Perophoridae, Corellidae, Ascidiidae, Styeli-
dae, Pyuridae, Molgulidae, and in Clavelinidae,
Holozoidae, Polycitoridae, Polyclinidae, and
Didemnidae (see Millar 1953a, Goodbody
1974), although it has not been reported for
every species. However it often is very incons-
picuous. It is particularly well developed and
conspicuous in Eudistoma spp., with numerous,
long tubules clustered around the outside of the
ascending limb of the gut loop.

gonads: Gonads of most aplousobranch taxa are

in the abdomen, in or beside the posterior end
of the gut loop. Exceptions are Polyclinidae (in
which they are invariably in a posterior
abdomen behind the abdomen), certain Dista-
plia (in which they are in a posterior abdominal
sac that is connected to the side of the abdomen
by a narrow neck), and Hypsistozoa (in which
the gonads are in the top of a posterior
abdominal stolon).

Most aplousobranch ascidians are hermaph-
rodites. They are either protandrous or prot-
ogynous, and the zooids in one colony have
gonads at more or less the same stage at the
one time. For instance, in Sigillina australis and
S. mjobergi the eggs are fertilised and begin
their development before the testis is mature;
and in Distaplia florida n.sp, and D. viridis the
testis matures before the ovary. With one
exception (Sycozoa anomala Millar, 1960),
Sycozoa colonies are dioecious, at any one time
all the zooids being either male or female.
Nevertheless it is not known whether or not
the colony remains the same sex through its
life.

Gonad and gamete size, especially ovaries and
eggs, change markedly throughout the Aplou-

14 MEMOIRS OF THE QUEENSLAND MUSEUM

sobranchia. Ciona produces many small
externally fertilised eggs, and so do diazonid
species. In other families ovaries are reduced
in size as, with replication, the zooids become
smaller. Eggs are larger, fewer and internally
fertilised as the increasing integration of the
colony accommodates incubation of the
embryos, either in the zooid or in the colonial
test.

Testes also reduce in size with decrease in
zooid size, however, they do not reduce quite
as markedly as ovaries do; and although follicle
numbers are reduced, their size often compen-
sates for this, the male follicles often becoming
larger as their number falls (see Distaplia), Since
the Aplousobranchia are almost universally
internally fertilised and viviparous, the concen-
trations of male gametes in the surrounding
waters need to be maintained.

The increase in the number of zooids through
replication compensates for smaller gonads in
each zooid (see also incubation of embryos).

gut, gut loop (Fig. 1b): In aplousobranch ascidians
the gut is always entirely posterior to the
pharynx. It forms a narrow vertical loop in most
taxa except Cionidae, Hypodistoma, Polvdis-
toma and the Didemnidae in which it forms
a more or less horizontal loop. The descending
limb of the gut loop in Aplousobranchia is from
the oesophageal opening to the point, usually
just proximal to the rectum, where the gut
reaches the posterior end of the abdomen and
turns into the ascending limb at the pole of the
loop. The ascending limb of the gut loop runs
beside the descending limb to terminate in the
anus, opening into the atrial cavity.

The anal opening is well anterior near the
base of the atrial aperture in Ciona and in the
Diazonidae, toward the posterior end of the
atrial cavity in most other taxa and usually
between the third and fourth or second and third
rows of stigmata in Holozoidae and Eudistoma,
respectively. Only in Pycnoclavellidae is the anal
opening at a level with the oesophageal opening,
at the posterior end of the atrial cavity.

Subdivisions of the gut found in Aplouso-
branchia are an oesophagus with or without a
prestomach swelling in it, a stomach, a duodenal
area, a mid-intestine often with a posterior
stomach swelling in it, and a rectum which
terminates in the (usually) bilabiate anus.

The prestomach is known only in Clavelini-
dae, having been reported in Clavelina cylin-
drica, C. moluccensis, C. nigra n.sp., and
Nephtheis fascicularis.

The oesophagus is long (occuping most of
the length of the long abdomen) in Pycnocla-
vellidae, Polycitoridae (with the exception of
the new genus Brevicollus), and Euherdmania.
In all other taxa the oesophagus is of moderate
length and the stomach is more or less halfway
down the abdomen rather than at its posterior
end,

Berrill (1950) ambiguously referred to the
cylindrical region immediately posterior to the
stomach as the posterior stomach, here called
duodenum. It is especially long in Eudistoma,
but is absent in Nephtheis, Euclavella n.gen.,
Sycozoa and the Didemnidae (which have no
divisions of the gut distal to the stomach).

The narrow mid-intestine (sometimes with a
posterior stomach along its length) intervenes
between the duodenum and the rectum. In
certain Distaplia, Hypsistozoa, and Neodistoma
n.gen. a distinct rectal valve is at the junction
of the rectum and the mid-intestine. The
posterior stomach is in the otherwise relatively
narrow mid-intestine of Pseuwdodiazona, Clave-
linidae (in the descending gut limb), Pycnoc-
lavella (in the pole of the gut loop), Polycito-
ridae and Stomozoidae (in the descending limb),
and Sigillina, Hypodistoma, Polydistoman.gen.
(in the descending limb). There is no posterior
stomach in Cionidae, Rhopalaea, Nephtheis,
Euclavella n.gen., Distaplia, Hypsistozoa,
Neodistoma n.gen., Sycozoa, and Didemnidae.

The ascending and descending limbs of the
gut loop in Aplousobranchia are not homol-
ogous with those of Phlebobranchia and
Stolidobranchia. In the latter two orders (in
which the gut is bent up alongside the pharynx)
the oesophagus, stomach, and proximal part of
the intestine comprise the ascending limb. The
intestine curves around in the pole of the loop
and the descending limb consists of the distal
part of the intestine and the rectum.

heart: In Aplousobranchia the heart is a straight,
curved or V-shaped tube usually at the posterior
end of the body, It is at the posterior end of
the abdomen in taxa dealt with below. In
Euherdmaniinae it is sometimes present halfway
down the posterior abdomen, and in Polycli-
ninae it is at the posterior end of the posterior
abdomen (see Berrill 1936).

incubation of embryos: All Aplousobranchia
except Cionidae and Diazonidae are viviparous,
brooding embryos and releasing tailed larvae.
In Clavelinidae the ovaries are relatively large,
producing up to 100 eggs at a time. These are
fertilised and are brooded in the distal end of

THE AUSTRALIAN ASCIDIACLA 2 15

the oviduel which, in some species, lies
horizontally across the posterior end of the
relatively roomy atrial cavity (see Clevelina
robusta o.sp). The larvae complete their
development (ree in the atrial cavity. In a few
species (c.g, C. mo/uecensis) there is a pouch
al the distal end of the oviduct in which the
embryos are fertilised and brooded. In Pycnoc-
lavellidae, which have a long oesophageal neck
and generally smaller zooids and smaller ovaries
than those of Clayelinidac, the eggs mature
sequentially. They are fertilised at the base of
the oviduct, and develop as they move up the
long neck of the zooid toward the atrial cavity.
Eggs are also fertilised at the base of the oviduct
and develop as they move up the oesophageal
neck in Polyeitorella and Cystodvtes, complet
ing their development in a brood pouch at thy
top of the abdomen,

Berrill (19354) believed that fertilisation at
the base of the oviduct was characteristic also
ol Polycitor and Eueistoma, However, this is
the exception rather than the rule in these
diverse genera. Fertilisation is as the base of
the oviduct in the Arctic Polvelror witreus Sars
(see Berrill 1948a) and in Fudistoma olivaceum
(see Berrill 1947b). OF the I4 species of
Eudistama documented by Van Name (1945),
only E. clarum appears to have eggs fertilised
at the proximal end of the oviduct (see Wao
Name 1945, fig. 57). Most of the other species
have eggs and embryos at different stages of
development crowded in the atrial cavity where
fertilisation probably takes place, Similarly, in
the Australian species of these genera. fertil-
isation usually i8 in the atrial cavity, and is in
the oviduet only in Pelveiter eirees and P.
annulus nap. In Atedistoma only few eges are
produced and they are fertilised and brooded
in the atrial cavity of the small, but numerous
zooids. In zooids with the larval trunk about
Imm long. only ong oy woembryos are brooded
at a time. Up to & embryos are found i the
atrial cavity of each zooid in those species with
particularly small larvae, in which the trunk is
not more than 0.5mm (e.g, Eudistoma elongatum,
E. layyani), Vhus in Euelistorma whe number of
eggs produced and embryos broaded by each
zooid is relatively low, and is directly related
to the size of the zooids, and inversely related
to the size of the larvae. In colonies in which
the rate of replication is fast the large number
of zooids producing egys may well compensate
for the small number that each zaoid produces.

In Holozoidae a brood pouch is partially
isolated from the vooid, allowing the embryo

to incutmile im the test independently of the
eoaid. A loug incubation time is thus possible
withour restricting the functions of the zooid.
Further. in some genera ( Distupliaand Scored)
the larva escapes from the disintegrating (esl
rather then being expelled through the atrial
aperture. Therefore the necessity for eggs and
embryos to remain small is removed, In this
lumily ovaries produce lew, but large exes,
embryos and larvae — same of the largest larvae
known in the Ascidiacea (up to 4mm in
Sigillina), and in the larvae of Distaplia and
Sveozea the adult organs are better developed
than in any other taxon, Replication is alse
rapid and the large numbers of zooids in each
colony all produce eggs. Thus the embryos
produced by a holovowt colony are laree.
numerous, can be brooded for a long time. and
the adult organs of the oozaoid (primary zooid)
and sometimes also blastovooids are well
advanced before release of the larvae. These
large larvae do not swine treely lor very long,
and their chances of recruitment fay away from
the parent colony appear minimal. unless the
colony itself is uprooted and moved around in
the plankton (as itis in Secozed spp.).

In some species (Sigi/lina granidisstrur,
Ay podistouma yastun and Distaplia rerinace-
fala) \here are abnormally large eggs which
rupture from the abdomen following fertilisa-
tion presumably at the base of the oviduct, and
the embryos incubate free in the test as they
do in all genera of Didemnidac. However. in
Polvclininae eges are fertilised and embryos
incubate in the atrial cavity, In Puherdmaniinae,
a variety of strategies for fertilisation and
ineubation of embryos reflect the polyphyleuc
vature of this subfamily. In Ewherdmania (like
Pyenoclavella) fertilisation is at the base of the
oviduer and embryos incubate as they pass up
the long oesophageal neck; in Peeweoedixiornta
(like Sigilina) a brood pouch is attached to (he
posterodursal corner of the thoraxt and in
Rirevella fertilisation is in the atrial cavity (as
in Polyelininae).

incurrent aperture: sce apertures,

internal longitudinal vessels: vessels on the inner
surface of the pharyngeal wall, running parallel
to its long axis. These vessels run over or
between the stigmata. They are present in all
phlebobranch and stalidobranch ascidians, and
in Ciena, and Diaronidue. Vestiges of the
papillae that support these vessels persist in the
branchial sac of some genera of Euherdmaniinae
(c.g. Preropolyelinum Millar, 1960) and
Polvelinum (see branchial papillae).

16 MEMOIRS OF THE QUEENSLAND MUSEUM

larvae: All aplousobranch ascidians except Clone
and the Diazonidac are viviparous, Larvae are
liberated from the adult vooids or colony with
fully developed larval organs (tail, cerebral
vesicle, and adhesive organs) and at least
partially developed adult organs (branchial and
alrial apertures, branchial suc and gut loop).

Larval ectoderm is particularly specialized,
with secretory functions associated with larval
settlement and the synthesis of test. Cloney
(1977) has investigated the fine structure of
larval adhesive organs, and has demonstrated
(in Distuplia vecidenialis) Sine extensions
projecting from the ectodermal cells into the
test to anchor it against the ectoderm, and to
carry secretions to the surface. Similar exten-
sions ot larval ectoderm from other parts of
the larval trunk have been observed in tany
luxa during the course of the this study viz,
in Syeozod (SY, brevicauda nsp.. 8. pulchra).
Sivillina (8. granddissinta sp), Polvettor (P.
translucidus), Eudistoma (angolanum group,
and £. inewbitunrn.sp.) and in Brevicollus agen.
Vhese extensions have terminal vesicles that
often are conspicuous in the surface test and
obscure the structure of the larvae. Other
ectodermal projections into the test have been
observed around the apertures of the oozooid
in Avedixtoma carnasim osp.. &. avatum and
£. purpurewn asp. Vhe larval rastrum (see Kott
1980, 1982a) of certain Diplosoma, in which
Prochloren symbionts are transferred from the
parental cloacal cavily lo the next generation,
may be formed by similar ectodermal extensions
over the posterior end of the haemocuel. The
fine structure and the functions of these
extensions deserve investigation.

‘There are basically 5 different types of larvae,
eoch with characteristic adhesive organs (sce
above), known in the Aplousobranchia, Gener-
ally each ts characteristic of a taxon or a group
of taxa, However, often there are anomalous
species with larvae that do not conform, and
the phylogenetic significance of the differences
between these larvae is not vet understood,

The known larval types are:

1. Thesmall, undifferentiated larvae of Ciena
and the Diazonidae develop from exter-
nally fertilised eggs. ‘They have 3 sessile
triradially arranged adhesive organs at the
anterior end of the larval trunk. Adult
Organs remuim relatively undillerentiated
until settlement and metamorphosis. The
lurva iy invariably small, its trunk being
about 0.1mm long (see Berrill 1950).

2. The moderately large. well developed

larvae of Clavelinidac, Distupha, Hypsis-
lozvd, Sycuzeu and Stomozoidae are all
telatively similar. They have 3 triradially
acranged sessile or stalked, adhesive
organs on 4 common stalk or plate that
is connected to the developing cozooid
only by a ventral stolon. The trontal plate
(in Clavelinidae) and the stalks of the
adhesive organs (in Distaplia and Hypyis-
fozoa) are often expanded into rounded
swellings (ampullae),

Despite these similarities, differences
exist in larvae as in adults, and a close
phylogenetic relationship ig not proposed
between Clavelinidae and Holozoidac.

‘The smaller larvae known in this group
are In the Clavelinidae with a trunk that
is 0.7mm long (Clavelina australis, C.
fecunda), but more often they are Imm
or more. There are only 2 rows of stigmata
in many of the species (C. ausrralis, ©
Jecunda, C. moluccensis and ©. baudinen-
six) while others have 4 rows (C. meridi-
unalis, C. aliva nap. and C, robusta nsp.)
or more (C\. pseudohaudinensis), Larvae
have many fewer stigmata per row Chun
the adult zooid and the gut loap is seldom
dillerentiated.

Larvae of Distaplia and Hypsistezog
have a larval trunk seldom less than 1.5mm
long and often more than 2.0mm, and they
have better developed adult organs than
those of Clavelina. The adult complement
of 4 rows of stigmata is present, the gut
loop is well formed and blastazooids are
present in many species.

Syeozoa larvae are simplified, with
trunks only about Imm long, no ampullary
expansions {rom the stalks of the adhesive
organs, no ocellus, and although the
epicardial sacs are often very conspicuous,
Without as many blastozooids as Distaplia
und Hypsistozea. However, the adult
organs in the oozooid are as well developed
as those in Diytaplia and the axial cone
in the adhesive organs is large.

Larvae of Clavelina dagysa and C.
brasiliensis, (Millar. 1977) are unusual
having apparently lost their adhesive
orguns, although they retain the frontal
plate. The small (0.5mm trunk) larva of
C. hauelinensis is also unusual. lacking a
stalked, frontal plate and a collar, or
saucer of cells around the shori-stalked
adhesive organs, This may be a primitive
condition, in which simple adhesive organs

THE AUSTRALIAN ASCIDIACEA 2 17

resembling those of oyiparous forms are
present. although they project on short
straight stalks rather than being sessile.
They do not have ampullary swellings
found in other clavelinid larvae.

. The relatively small larvae of Polyciter and

Eudistoma (Polycitoridae), and most
species of the Polyclinidae, have a larval
trunk not more than Imm long and stalked
adhesive organs present in the mid- vertical
line anteriorly. Conical, sometimes bilobed
ectodermal ampullae are present in the
anterior mid-line alternating with the
adhesive organs, and/or in one or more
rows along each side of them (especially
in £udistoma spp.). Polyclinidae have
epidermal vesicles in the larval test as well
as the ampullae. Adult organs are mad-
erately well advanced in the larvae,
although not as well as in the larger larvae
of Distaplia, Sycozoa and Hypsisxiezea,
There are usually 2, but occasionally (in
certain Eudistonta) 3, rows of stigmata,

Didemnidae and Cysiedites (Polycito-
ridae) also have larvae of this general type.
although their adhesive organs have
conical protrusions rather than the flat-
topped ones of Polycitor and Eudistoma.

Polycitar annulus n.sp. and P. circes do
not have the same larvae as other species
in the genus. Instead they have triradially
arranged adhesive organs. They resemble
larvae of Clavelina baudinensis, and
possibly reflect the common ancestry of
aplousobranch ascidians [rom a predia-
zonid ancestor,

Cystadytes has a circular perforated fold
of test surrounding the stalked adhesive
organs. [t may have evolved fronv the
polycitorid larval type.

The genera Sigi/lina and Hypodistoma
contain the largest Jarvae known in the
Ascidiacea (up to 4mm fong larval trunk),
They have 2 or 3 unusually large adhesive
organs in the anterior mid-line. Adhesive
organs are sessile, on u frontal plate
connected to the oozooid by a ventral
stolon in Aypodisioma. In Sigillina the
anterior end of the larval trunk (which
contains the larval adhesive organs) is
separated from the oozooid by a waist.
Adhesive Organs aré on short thick stalks
and surrounded by ectodermal vesicles
that arise from the ectoderm around the
base of these stalks. just in front of the
waist, Adult organs in these large larvae.

rn

are not well differentiated. The 3 rows of
§ligmata are present, bul the gui loop
usually cannot be distinguished. These
larvae have short tails and could be poor
swimmers, probably causing population
isolation. resulting in relatively numerous
species in this southern hemisphere group
of genera,

The large larva of Sigi/linag mjohersi.
with 2 deeply inVaginated tubular adhesive
organs (like those of Pycnoclavellidae). is
anomalous, suggesting Sigi/lina, as pres-
ently defined, is polyphyletic.

. Larvae with adhesive cells in the base of

deeply invaginated, tubular adhesive
organs which evert on settlement occur in
Pycnoclavellidae, Evherdmania and Sig-
illina mjobergi. These larvae are moderate
to large (0.7 to 2.0mm long trunk). They
have 3 (triradially arranged) or 2 (in the
anterior vertical mid-line) adhesive organs,
Sometimes there are deep Jongitudinal
furrows in the ectoderm uround the
anterior half of the trunk (ampullae:
Trason 1957) and often the otolith is
absent. The oozoeid is not always well
advanced before setlement, usually the gut
loop is not differentiated and only one or
2 rows of stigmata can be seen. Exceptions
are Ppenoclavella detorta with 6 rows of
stigmata and Euclavella n.gen. clavifarniis
with 4 rows. Both have 3 adhesive organs,
a well differentiated gut loop, and neither
have an otolith.

These larvae have no obyious morpho-
logical affinity with any of the other groups
except the primitive cionid-diazonid
larvae. They may indicate an origin from
forms with a sessile group of adhesive cells
Which subsequently invaginated into the
larval haemocoel. The larvae may indicate
a felationship between Pycnoclavellidae
and Euherdmaniinae, and they are evi-
dence of the polyphyletic nature ol the
latter sub-lamily.

In all incubating aplousobranch larvae
the tail winds around the mid-line. As it
extends up the anterior face of the trunk
and (if long enough) back along its upper
gurface. it passes to the night of the
adhesive organs (if these are in a vertical
line) and the sensory vesicle. If adhesive
organs are triradially arranged 2 are on
the left and one is un the right of the tail.
(See also adhesive organs).

18 MEMOIRS OF THE QUEENSLAND MUSEUM

neural complex, — ganglion, — gland: a closely
associated neural ganglion and gland beneath
the epidermis in the intersiphonal region, In the
Aplousobranchia (as in the other enterogonid
suborder, Phlebobranchia) the sometimes flask-
shaped neural gland is ventral to the ganglion,
and its duct opens directly into the pharynx
in the mid-dorsal line at the anterior end of
the dorsal lamina. In most Aplousobranchia the
opening of the neural gland is a small,
inconspicuous, sessile, simple vertical or
horizontal slit, or pit. Ciona is the exception,
the opening of the gland (the ciliated pit) being
complex and folded, and opening on a tubercle
as it does in phlebobranch and stolidobranch
ascidians (see Millar 1953a).

oviparous: externally fertilised (see also

viviparous),

proximal: the end of an organ or structure away
from which the contents or products move. (See
also distal).

pyloric gland: see gastro-intestinal gland.

rectal valve: two backward-projecting caecae at
the proximal end of the rectum, found in certain
Distaplia and in Hypsistozoa and Neodistoma
n.gen,

replication: the vegetative process whereby clones
of adult zooids are produced to form colonies.
One or another process of replication occurs
in all aplousobranch families except the
Cionidae (see also cloacal systems, colonies,
epicardial sacs; and Berrill 1935b, Kott 1982b).

retropharyngeal groove: the groove that connects
the postero-ventral end of the endostyle with
the postero-dorsal oesophageal opening.

spicules: small (0.01 to 0.1mm diameter), calcare-
ous (calcite) crystalline structures found in
Didemnidae and in Polycitorella and Cysto-
dytes. They appear to be synthesised in localised
regions of the test where it is in close contact
with the zooid epidermis on each side of the
ventral mid-line. The site of spicule formation
in Didemnidae is well documented (Lafargue
and Kniprath 1978) but that in Cystodytes and
Polycitorella is less certain. Spicules are plate
like (Cystodytes), star-shaped (Didemnidae,
Polycitorella), or spherical (Didemnidae,
Polycitorella).

vegetative stolon: see epicardium.

Suborder APLOUSOBRANCHIA Lahille, 1887

The suborder contains families of the Ascidiacea
in which the body is divided into the thorax

(containing neural apparatus, branchial and atrial
apertures and pharynx surrounded by the atrial
cavity) and the abdomen (containing gut loop,
heart and gonads). The epicardial sacs, developed
in the embryo as outgrowths from the posterior
end of the pharynx, have a regenerative function.
They persist as sacs or remnants of sacs in the
adult abdomen and sometimes extend into a
posterior abdominal extension. Most species of
the Aplousobranchia are colonial. With the
exception only of the Clavelinidae, the endodermal
epicardial sacs are the tissue from which all body
organs of replicated zooids develop following
horizontal division of the zooid at one or more
levels posterior to the thorax (Berrill 1935b). In
Ciona and in most Rhopalaea the generative role
of the epicardial epithelium is confined to the
repair of parts of the body following loss or
damage, for in these solitary taxa vegetative
replication does not occur.

In Clavelinidae replicated zooids develop from
isolated terminal ampullae of test vessels in the
colony stalk (see Berrill 1950). In the few Clavelina
that are solitary, replicates either are separated
from one another following their formation (as
in Clavelina miniata Watanabe and Tokioka, 1973
and possibly C. oliva n.sp.), or they develop
following resorption of the parent zooid, as in
Clavelina ostrearium (Michaelsen, 1930) and
Clavelina meridionalis (Herdman, 1899).

As discussed for colonial species of the
Stolidobranchia (Kott 1985), zooids decrease in
size as the replicative process evolves and becomes
more prolific, and colonies become more highly
organised. Most families of Aplousobranchia have
relatively few, large, yolky viviparous larvae.
These are incubated either in the zooids, or in
brood pouches, or free in the test. Exceptions are
Ciona and Diazonidae, in which fertilisation is
external, and numerous small larvae with poorly
organised larval organs are produced. The size
of the larva, the evolutionary history of the species,
and its degree of colonial organisation are all
directly related to one another and inversely
related to the numbers of embryos produced and
incubated (see Berrill 1935a, 1955; Kott 1974,
1982b, 1985).

The most fundamental plesiomorphic character
in the Aplousobranchia is possibly the capacity
for replication. As indicated, the process is not
the same in all families, and aspects of the various
processes are often useful indicators of phylogeny.
Thus, although in Clavelinidae, Pycnoclavellidae
and Holozoidae a well developed vascular stolon
from the posterior end of the abdomen is involved
with replication, the process is different in each

1HE AUSTRALIAN ASCIDIACEA 2 19

family. Replication in Clavelinidae is from the
terminal ampullae of the vascular process, in
Holozoidae it is by division of the stolon, and
in Pycnoclavellidae the abdomen itself is divided,
In Polycitoridse and Diavonidae the process is
the same — the abdomen divides to form the
replicates. This suggests the two [umilies are
related. Kort (1982b) has summarised the range
of different replicative processes Known in. the
Aplousobranchia, Despite differences in the
process, morphological adaptations associated
with increasingly prolific replication of any type
are usually convergent, viz, size and siniplification
of the zooids. size and form of the colony. and
ils degree of organisation and capacity ta brood
viviparous embryos.

Other possibly plesiomorphic characters,
probably not convergent, that could be indicative
of common ancestry, are the larval adhesive
organs. The everting cones of the majority of taxa
(Clavelinidae, Holozoidae. Polycitoridac, Polye-
linidac, Didemnidve) can he traced to the
primitive, simple, non-everting, sessile, conical
type found in the small larvae of all ovipurous
ascidians (phlebobranch and stolidobranch taxa
as well as Cioma und the Digzonidae). However,
deep tubular invaginations that carry the secretary
cells back into the larval trunk, in Pyenoclayel-
lidac, Sigi//ina mjabergi and Eukerdmania
{Euherdmaniinae), do not have obvious relation-
ships with the other types of adhesive organs (see
Cloney 1977; see alsa Annotated Glossary.
adhesive organs).

Characters associated with the progressive
evolution of cloacal systems. ure often convergent
and usually indicative of not more than generic
status — only rarely are families so distinguished
(vic. Euherdmaniinac from Polyclininae). Thus,
inthe Holozoidue. Sigilline (With atrial apertures
on siphons opening independently) is distinet fram
Sveozea and Distaplia which have cloacal cavines
and wide atrial apertures opening into them,
Differences in the arrangement of zooids in the
colony, either in cloacal systems or with atrial
siphons opening separately lo the exterior. are
usually regarded as significant only at species level.
Thus in some, but not all, Eudisroma zooids are
arranged in circles around rudimentary cloacal
ecavides, and Distaplia has either circular. or
radiating double row, systems.

Reduction in gonad size is another convergent
character associated with replication, a colonial
habit and viviparity (see Kote 1982b). However.
the location of gonads in the zooid is only
sometimes convergent. Polyeitoridae have small
zooids With gonads in the abdomen (in (he gut

loop). Similarly, neither Holozoidae nor Didem-
nidae have a posterior abdomen and their gonads
are algo in the gut loop. in What appears to
represent maintenance of their primitive position
rather than convergence with the Polycitoridac
However, the presence of gonads in & poslerioe
abdomen in certain genera of the Euherdmaniinac
may be convergent, rather than indicative of a
direct relationship with Polyclinidae eg
Preudadiytoma hasan apparently closer phiyloge-
netic relationship with Sigi/lina than with
Polyelinidue (with which tt currently is classified).
The Euherdmaniinae will be discussed in Part 3
ol this work.

Holosgidae and Didemnidae both produce
relatively ew and large eggs. Embryos are brooded
in thoracic pouches in most species of the
Holozoidae and in Arrioluny Kott, (984 (Didem-
niduel, A few species of Holovoidae have
particularly large eggs which rupture directly from
the abdomen to develop in the test as they do
in most Didemnidae. These appear convergent
characters associated With the relative size of egyrs
and zooids, for a direct phylogenetic telalionship
between Holozoidae and Didemnidae is denied
by their processes of replication the division
of a posterior abdominal vegetative stolon in
Holovoidae, and oesophageal budding and
division of the zooid in Didemnidae

Unlike Phlebobranchia and Stolidobranchia,
where phylogenetic relutionships can be identified
with a degree of confidence, relationships between
many recognised famibes ol Aplousobranchia are
obscure. Their morphology is diverse, presumably

as a result of wide radiation, Subsequent

extinctions have left gaps in the extant fauna ane
a shortage of evidence from which to dedyce
phylogeny. Further, several monotypic taxa have
remarkably wide geographic ranges, but are
known rom only isolated records and Jocnlijies
(viz. Pseudodiazona, Stomozoidae n.tum,, Neph-
theiy and Auclavella n.gen), suggesting thal
conditions favouring radiation in these groups are
not as favourable now as they were in the past,
and thal the present populations are relict ones.

The Aplousobranchia is not well represented
in the abyssal fauna of any ocean. Possibly its
characters are not readily adapted to conditions
in ocean depths. One relevant character may be
the large, viviparous larvae (associated with a
colonial habjt) that are tree for only very short
periods, und are unlikely to be efficient swimmers,
These inhibit gene flow between poptlations
isolated by distunee ar otber factors, The internet
fertilisation that is necessarily associated witli

0) MLMOIRS OF THE QUEENSLAND MUSEUM

yiviparous habit may also represent a selective
disadvantage at great depths where conditions on
the sew floor apparently accommodate only sparse
populations. These reproductive strategies may
reflect selective pressures that have affected
evolution of aplousobranch asetdians and patterns
of distribution of extant forms.

Only few of the Known genera of Aplousobran-
chia are not Known from Australian waters.

Key tote PAnMioesor Lib APL Olsebie ane HLA

). Internal longitudinal branchial vessels or
forked papillae present..-.....-..-..-- 2
Internal longitudinal branchial vessels and
forked papillae absent ..........,.0,0003
Gut forms a horizontal loop .... CLONIDAE
Gut forms a vertical loop..,. DIAZONIDAF
3. Branchial apertures with smooth borders. ..4
Branchial apertures with lobed borders ....5
4. Ovary contains < 10 ova: larval adhesive organs
inverted tubes... PYCNOCLAVELLIDAE

new family
Ovary contains > LO ova; larval adhesive organs
not inverted tubes...... CLAVELINIDAE
5. Gonads and heart in a posterior
abdomen ........0.+.,-POLYCLINIDAL
Gonads and heart not im @& posterior
ACMI oe oe pe oe te pee ae eles oes 6
6. Lobes of apertures with secondury serra-
lions .......STOMOZOIDAE new family
Lobes of apertures withuul secondary
SUIPUIONS .2 i epee teeter eteeres vemet
7. Replicates generated from vegetative stolon in
stalk or in base of colony: embryos usually
broaded in thoracic pouch: calcareous
ypicules never present .... HOLOZOIDAE
Replicates not generated [rom vegetative stolen
in stalk or in base of colony; embryos seldom
brooided in thoracic pouch; calcareous
spicules sometimes present ,.....eceee ee 8
8. Cloacal systems seldom present*: atrial
apertures always -lobed; replication by
hocizontal division of the
abdomen............POLYCITORIDAE
Cloacal systems always present, atrial apertures
scldom 6-lobed, replication by oesophageal
DUI © nie hehe oe eaten en DIDEMNIDAE

bh

noe

* The new genus Exosroma is the only taxon of

the Polycitoridae with a true cloacal system.

Family CLONIDAL, Luhille, 1887

Ciona, the only known genus of this family. is
characterised by its solitary habit, horivontal gut
Joop posterior to the thorax, persistent openings
of the epicardial sacs into the pharynx, lohed

apertures, und large branchial sac with numerous
rows of stigmata and internal longitudinal vessels
supported on papillae which project into the
jumen. What are thought to be light sensitive ocelli
are present between the lobes of the apertures.

Kott (1969) first drew attention to the aplou-
sobranch nature of the Cionidae, which formerly
had been included (with the Diazonidae) in the
Phicbobranchia on the basis of the internal
longitudinal branchial vessels and theirsupporting
papillae which are similar to those of certain
phlebobranch ascidians (see Huus 1937, Van
Name 1945, Berrill 1950), A tendency to lose
internal longitudinal branchial vessels is a
vonvergent adaptation associated with the
development of vegetative replication and conse-
quent reduction in zooid size in both phlebobranch
and stolidobranch as well as in uplousobranch
ascidians (Kott 1985). Consequently, the absence
of these vessels (rom the small branchial sacs of
colonial aplousobranchs is a secondary adapta-
tion, and not 4 plesiomorphic character indicating
a phylogenetic affinity at the subordinal level.

As well as its large branchial sac and internal
longitudinal branchial vessels, Ciona has other
apparently primitive characters that persist in
solitary Phlehobranchia and Stolidobranchia
viz. small larvae and an oviparous habit. In all
sub-orders, convergent adaptations ussociated
with vegetative replication and a colomal habit
include viviparity and the development of large,
Well Organised larvae with well developed larval
and adult organs (see Kott 1985). Thus, small,
largely undifferentiated cionid-type larvae, with
simple triradially arranged adhesive organs, do not
indicate a close phyloyenetic relationship between
Ciona and solitary phlebobranch ascidians, They
ure associated with a solitary, oviparous habit and
their loss represents another adaptation associated
with the colonial habit that results from vegetative
replication,

The hypothesis of a closer relationship between
Ciona and Aplousobranchia is more compelling
than one between Ciona and Phlebobranchia. It
is based on the existence and regenerative role
of the epicardial sacs im Ciona and in aplouso-
branch families. Individuals of Crona intestinalis
have ihe capacity to regenerate lost organs, the
regenerative tissue being endodermal epicardium,
Epicardial epithelium is the regenerative tissue in
the process of replication in most aplousobranch
ascidians( Hirsehler 1914, Berrill 1935b), Although
regeneration and repair occur in Clone, spontatie-
ous division of the zooid resulting in replication
does not. The regenerative capacity of the
epicardial tissue in Clone involving, selection of

THE AUSTRALIAN ASCIDIACEA 2 2

epicardial tissue for a regenerative function, rather
than the excretory role it has assumed in
Phicbobranchia, probably represents an early
stage im the evolution of the aplousobranch
vegetative process, and the separation of Aplou-
sobranchia trom Phlebebranchia.

The close relationship between Ciana and other
aplousobranch ascidians is supported by the
oxidation state of the Vanadium present in the
blood cells, vanadium (IV) in aplousobranch and
vanadium (IIL) in phlebobranch families (Haw-
kins. Kott, Parry and Swinehart 1983).

Test vessels of Ciona arise trom the posterior
end of the body and extend out into the posterior
test extensions (villi). Although these vessels are
primarily ectodermal, as in all ascidian species,
they have a mesenchymal septum between the two
channels (see Millar 1953a), as im the aplouso-
branch family Clavelinidae and provide a further
indication of affinity with Aplousobranchia,

Araneum Monniotiand Monniot, 1973, assigned
by its authors to the family Ciomdae has no
apparent cionid characters. It appears a highly
adapted, ubyssal phlebobranch related to the
Ascidiidae.

Genus Ciona Linnaeus, 1767
Type species: ycidia intestinaliy Linnaeus, 1767

A very soft test in combination with strong.
external longitudinal muscle bands that extend the
whole length of the organism, make Ciona
particularly contractile. There is also an inner layer
of fine circular muscles. The branchial aperture
is usually 8-lobed and the atrial aperture 6-lobed,
both with single, probably light sensitive, ocelli
{see Millar 1953a) between the lobes.

Hoshino and Nishikawa (1985) have exhaus-
tively reviewed Ciona. They have examined many
of the available specimens that have formerly been
described, as well as additional material from
Arctic, boreal and cold and warm temperate
European waters, the Mediterranean, the AUantic
coast of North and South America, the coast of
California and Japanese waters as well as sonic
specimens from Western Australia. Port Jackson
and New Zealand. They conclude there are two
closely related species of the genus — one, Crona
intestinalis (Linnaeus), with a wide cosmopolitan
range, as indicated below, and one, Clana savignyi
Herdman, recorded principally from Japan, but
also recorded from Alaska (as C. frestinalis:
Ritter. 1913) and Hong Kong (C. intestinalis: Kou
and Goodbody,, 1982, part), A further record from
Argentina (Pisano, Rengel and Bustuoabad 1971).
assigned to C. yavignyi on biological grounds, is

dilhicult to interpret in View of the otherwise
limited range of the species from Japan to the
northern Pueilic. Clone intestinalis is the only
species recorded from Australia,

Two further species are possibly valid. wiz. the
southern polar C. waarctica Hurtmeyer, 19 Lt (see
Monniot and Monniot 1983) which has a
distinctive Mattened. leaf-like ovary (see Hoshine
and Nishikawa 1985), and the north-castern
AUantic abyssal C. imperfecta Monnmiot and
Monnint, 1977. Two possibly valid subspecies, ©.
intestinalis longissima Hartmeyer, 1899 and ©.
intestinaliy gelatinosa Bonnevie, 1896, both with
a postetior abdominal vascular extension, have
been described from Archic waters (see Hoshino
and Nishikawa (985)

Ciona intestinalis (Linnaeus. 1767)
(Fig. 3, Plate 1a)

Tethvunr soclahile Guannerus, 1765, p. 99.

Ciana soctabilis: Hartmeyer, 19154, p32). 19 15b, p.254

Aseitia inrescinalis \innaeus. 1767, p. (087. Cuvier, (81S
p32, Couthony, 1838, pli, Dekay, 1843. p.259.
Sars, IRS1, p. 156, 1859. p.64,

Phallusia investimalis; Savigny, (S16, p.107,

Ciona intestinalis: ? Fleming, 1822. 512, Kuppter. 1875,
p.207. Weller 1875, p.ll7. Schmelty. (R79. p89
lraustedt,, $82. p.454. Roule, (884, 7.7, Castle, [R96,
pls 1-13. Damas, 1899, p,}. Herdiman, 199, 98
Hartmeyer, 1903, p.297; 19158, p.d2h: 1920, p20,
1924.4. typics p90. f. tenella p.103. 1 ocellata p,t04,
Alder and Hancock, 1907, p.47, Kesteven, 1909, |,
sydneiensis p.2h2, Van Name, 912. f. tenella p.anay
1945, f. tenella p.l63.? Huntsman, 19120, pox,
I912b, ppll2, 114. 119, Sumner, Osburn and Cole,
1913, p.730, Pratt, 1916, p.607. River and Forsyth,
1917, 9.457. Hartmeyer and Michuelsen, 1924, p.259,
Aroback, 1934, var, tenella p.17, Brewin, (950, p, 347,
Millar. 1953a, p.1, 19634, p.720; 1970, f costata p14,
Kotl, 1952. p.al) 1976, p54. Kott and Goodbody,
1982, p.505 (part. QM GI2780). Hoshinn and
Nishikawa, 1985, poo.

Axvidia canina Mueller, 1776, p-225.

Ciona cantina: Kuppler, $875, 9.206. Traustedr, [ASO
p.432.

Ascidia ocellara Agassiz, 1850, p.1 59. Binney, IS7IL p24
Dall. 1270, p.255,

Clana ocellata: Verrill, 1880 p.251, Mebyonald, 1889.
p.858, Hartmeyer, 1903, p.d0l.

Ascidia tenella Stimpson, 1852. p. 228; 1854, p.20: |ROO,
p.2. Binney, 1870, p.24. ? Ball, 1870, p.255-

Ciona tenella; Vertill, (871, p99; 18724, p.6, 1872b,
p.2ld: 1873. vol.6 pp. 435, 440, 1874, vol? pp. 413,
504, 1880, p.25. Verrill and Smith. 1873, p.698
Kingsley, [90]. p, 183. Whiteaves, 1901. p.267.
Hartrnever, 1903, prot.

Aseidia pulehella Alder. 1863, p.157)

Clon treo Sfuiler, 1904, p, 24 (part, specimen from
Station al 2)

az MEMOIRS OF THE QUEENSLAND MUSEUM

Ciona pulchella: Alder and Haneock, 1907, p.14.
Hartmeyer. 19]5a, p,32}.

Ciona fascicularis Hancock. 1870, p.364. Kuppfer, 1875.
p.207. Alder and Hancock, (907, p. IS. Hartmeyer.
1915a. p32],

Ctona diaphanaea Kesteven, 1909, pp.262. 285,

Ciona robusta Hoshino and Vokioka, 1967, p.275,

Ciona velatinosa: Monpiot, C,, 1969b, p.1133.

Dis vRiRUTION

New Recogps: Western Australia (Albany town jetty,
WAM 744.83). South Australia( Adelaide outer barbour.
SAM E1978-9). Victoria (Portland Harbour, QM
GH34; Port Melbourne, QM G10048).

Previovsty Rrecororo: Western Australia (Canning
River, Swan River — Hartmeyer and Michaelsen 1928;
Fremantle, Albany Hartmeyer and Michaelsen [928,
Kott 1952), South Australia (Port Adelaide — Kott
1952), Tasmania (Habart — Kott 1952), Vietona (Port
Phillip Bay --- Kott 1976). New South Wales (Port
Jackson — Herdman 1499, Kott 1952). Queensland
(Rockhampton Kott 1952). Indonesia (2MA TU333
specimen from St, 312 Sluiter 1904),

Re-examinauion of Hong Kong material in the
Qucensland Museum (see Kott and Goadbady 1982)
shows the species on the hull of the Fisheries Vessel
(M62) to be C. intestinalis (QMG12780), AIL other
specimen lots, both from inside Tolo Harbour and in
the South China Sea, are C. savignyr.

Ciwna intestinalis is known also from the Arctic, the
cast Atlantic part of the boreal region, around the British
coasts. the western seaboard of Europe, the Mediter-
ranean, parts of north and south America, Cape Verde,
and New Zealand (Brewin 1950, Millar 1943a), Van
Name (1945 p.162) summarises the American records
as ‘frum Greenland and Davis Strait south to southern
Massachusetts and Rhode Island and on the Pacific coast
from southern Alaska to the southern end of California’.

However, the only confirmed records on the Pacifie
coast of north Amenea (see Hoshino and Nishikawa
1985) are from California. As C. savignyr has a known
range that includes the Pacific coasts of Alaska and
Canada, it is possible that records of Dall (1870) and
Huntsman (1812a. b) are of C. savignyi rather than C,
intestinalis.

The Australian records are all from harbours and port
installations, and several (Hartmeyer and Michaelsen
(928) are from brackish locations well up river estuaries.
However. the most recent records are nol less than 10
years old. The species appears to be disappearing from
Australian harbours, where, from 195010 1960, crowded
populations were known to occur, Van Name (1945)
observed the same phenomenon on the northern coast
of New England where Ciona disappeared almost
completely from a region where it had been common
in the mid-19th century, The species 1s llourishing im
Hong Kone and is e¢specially common in the same

Fig. 3, Crona mrestinalis (QM GH434): a, terminal
ampullite: b, individual in test showing gut-loop and
muscles. Scales: a, ]mm: b, 5mm.

THE AUSTRALIAN ASCIDIACEA 2 23

habitats (on ships hulls, wharf piles etc) as it used to
occupy in Australia (Kott and Goodbody 1982).

It is possible that C. intestinalis is adapted for a habitat
on under surfaces such as ships hulls — an adaptation
that would favour its transport and cosmopolitan
distribution on ships — a proposal first made by Van
Name (1945). This proposal was repeated by Kott (1969,
1974). Kott (1974) suggested that populations were
confined to ports and harbours because there they could
be maintained in sufficient densities for successful sexual
reproduction; while in the conditions outside these
protected locations larvae would be dispersed and
ultimately reach sexual maturity in isolation from other
individuals of the species.

DESCRIPTION

Exrernat AppeARANCE: Individuals are
always found crowded together in large popula-
tions. They are cylindrical, up to [Sem long when
extended, and usually hang vertically from under
surfaces, fixed by their posterior ends. The siphons
are of variable length, the 8-lobed branchial siphon
terminal and the 6-lobed atrial antero-dorsal. The
test is soft and translucent. When the animal is
contracted it is very wrinkled on the surface, but
internally the soft gelatinous mass becomes
thicker. Occasionally tubicolous worms and other
epibionts are attached sparsely to the outer surface
and the outer layer of test is sometimes quite hard
and leathery.

The single, possibly light sensitive, ocellus
between the lobes of the apertures each consists
of a central red spot surrounded by a patch of
orange pigment. Posteriorly the test is produced
into short projections (villi), that help to anchor
the animal, and that contain the double-channelled
test vessels with large (1.5mm diameter) spherical
terminal ampullae.

INTERNAL StRUCTURE: The most conspicuous
feature of the body wall is the long parallel muscle
bands, 6 on each side, 4 of which extend from
the branchial siphon to the posterior end of the
body; and 2 from the atrial siphon to the same
point at the posterior end of the body. There also
is a pair of fine ventral muscles along each side
of the endostyle. Anteriorly the longitudinal
muscles extend along the siphons beneath circular
siphonal muscles. A layer of circular muscle fibres
is present beneath the longitudinal muscles. From
60 to 100 simple branchial tentacles (the number
increasing with the size of the individual) encircle
the siphon base. Larger tentacles, of 3 orders of
size, alternate with rudimentary ones. The dorsal
tubercle, in a shallow prebranchial area, has a
simple U-shaped slit, with the horns turned out.
In larger specimens the slit becomes convoluted
and complex, with some side branches. A row
of pointed, tentacle-like, antero-posteriorly

flattened dorsal languets, each expanding from a
transverse vessels where it crosses the dorsal sinus,
extends the whole length of the branchial sac, and
curves to the right of the conspicuous oesophageal
opening at the posterior end.

The endostyle also extends the whole length of
the branchial sac and continues posteriorly into
a curved and usually (but not always) pointed
evagination from the postero-ventral corner of the
branchial sac — the endostylar appendix. Two
of the newly recorded specimens (QM GH34) have
a short endostylar appendix, rounded at its tip.
Occasionally, the appendix is turned up to the
left of the branchial sac (QM G10048; see Roule
1884, pl. fig.5). The retropharyngeal groove
extends across the posterior end of the pharynx
from the base of this appendix to the oesophageal
opening. The small paired openings to the
epicardial sacs are close together in the retropha-
tyngeal groove just dorsal to the base of the
endostylar appendix.

The most conspicuous feature of the branchial
sac are the internal longitudinal vessels, bearing
spoon-shaped papillae that project into the
pharynx at their junctions with the transverse and
parastigmatic vessels. There are from 30 to 130
longitudinal vessels per side, increasing in number
as the individual grows. Stigmata are long and
narrow, and, like the longitudinal vessels, increase
in number with the size of the individual, from
4 to 8 per mesh.

The gut loop is behind the pharynx — in an
abdomen — although there is no constriction of
the body wall separating it from the thorax. The
oesophagus, from the postero-dorsal corner of the
pharynx, curves postero-ventrally slightly to the
right of the midline and opens into an almost
spherical stomach that is more or less tapered at
each end and lies in the dorsal curve of the
posterior end of the body, The stomach has about
40 longitudinal ridges in its inner lining. From
the distal end of the stomach, the intestine curves
anteriorly and then dorsally to lie across the
posterior end of the body to the left of the stomach.
The rectum extends anteriorly, dorsal to the
gonoducts, and opens about two-thirds of the
distance up the branchial sac in a lobed anal
aperture.

The gonads are also in the abdomen, the testis
follicles being minute tubules connected by vasa
efferentia, and forming a furry-looking coating
over the stomach and intestine. The ovary, asimple
sac becoming larger and Jess regular in older
individuals, lies to the left of the stomach and
just behind the horizontal limb of the intestine.
Male and female ducts extend anteriorly inside

24 MEMOIRS OF THE QUEENSLAND MUSEUM

the rectum. Both gonoducts extend anterior to
the anus, however, to open at the base of the atrial
siphon. The tip of the male duct is swollen into
a small bulb that has in the vicinity of 20 separate
minute tubular openings on its upper surface.
There is usually a cap of red pigment over the
terminal bulb that persists in alcohol preservative
over many years.

REMARKS: Ciona intestinalis has an endostylar
appendix with epicardial openings close to it, and
the tip of the male gonoduct has a red pigment
cap over it, Ciona savignyi lacks an endostylar
appendix and has epicardial openings close to the
oesophagus. Some C. intestinalis are distinguished
further by the cuticular layer of the test acquiring
a leathery consistency.

A distorted and mutilated specimen from
Indonesia (Flores Sea ZMA TU333 Siboga station
312) assigned to Ciona indica Sluiter, 1904 is a
specimen of Ciona intestinalis, The openings of
the gonoducts are mutilated anterior to the anus,
and their exact form and position could not be
determined. However, the endostylar appendix is
present in the position usual for C. intestinalis
at the distal end of the endostyle; secondary
branchial papillae, though small and often
compressed, are also present (Sluiter 1904 pl.IV
fig 2); and, as Nishikawa has reported (Hoshino
and Nishikawa 1985) the muscles, gut, gonads,
and epidicardial sacs and their openings are all
characteristic of C. intestinalis. The flaccid and
mutilated test of this sessile specimen was stuck
onto the firm, gelatinous test of portion of a
polycitorid colony, but it does not appear that
the living specimen was so attached. Specimens
of Ciona indica from Siboga station 49 (also from
the Flores Sea) have been found to be conspecific
with Rhopalaea crassa (see Hoshino and Nishik-
awa 1985).

Detailed accounts of the morphology and
histology of C. intestinalis are given by Roule
(1884) and Millar (1953a).

Family DIAZONIDAE Seeliger, 1906

Members of the family display primitive characters
shared with the Cionidae, viz. numerous inner
longitudinal branchial vessels, a large branchial
sac, and a gelatinous, translucent test. It is the
only other family of the Aplousobranchia that,
like Cionidae, has large numbers of externally
fertilized eggs, and larvae with sessile, triradially
arranged adhesive organs each consisting of a
group of specialized epidermal cells and a cerebral
vesicle but little other organisation of trunk organs
(Berrill 1950), Also like Cionidae, zooids have 6-

lobed incurrent and excurrent apertures. The gut
loop is vertical and posterior to the branchial sac
and usually encloses the large gonads — although
these are sometimes present in a posterior
abdomen. Gonoducts open near the anus, well
anterior near the base of the atrial siphon, as is
usual for oviparous species (see Kott 1985). Body
muscles are longitudinal, extending down the body
from both siphons. No oblique muscles extend
posteriorly from the endostyle as in Clavelinidae.

The family appears related phylogenetically to
Cionidae, being separated from it by the extension
of the gut into a vertical rather than horizontal
loop, and by the progressive development of
vegetative replication through simple strobilation
of the abdomen involving the epicardial sac as
the regenerative tissue (see Berrill 1935a, 1950 for
Diazona), The mesodermal septum that develops
in the vascular stolon of Ciona intestinalis is not
present in Diazonidae.

Species range from solitary individuals
(Rhopalaea) to colonies with completely
embedded zooids (Syndiazona, Pseudodiazona).
Vegetative replication, although it is not prolific,
takes place in most species. In Rhopalaea a
number of species are solitary but regeneration
of the thorax is apparently a common occurrence,
Progressive reduction in zooid size with the
evolution of more prolific vegetative replication
is well demonstrated in this family — the zooids
of solitary Rhopalaea being much larger than
those of colonial Diazona spp.

There is some variation in the course of
longitudinal muscles. Generally they extend along
the thorax and the abdomen. However, in
Rhopalaea crassa they are confined to the thorax,
and in R. nordgaardi they continue onto a vascular
stolon. In both Tylobranchion and Pseudodiazona
there is a true posterior abdomen with muscles
extending onto it from the abdomen, and with
gonads and heart in it that appear spilt over from
their primitive position in the gut loop. These
changes (possibly related to reduction in zooid
size associated with increasing efficiency of
vegetative replication as the colonial habit
evolves), suggest a relationship with Polyclinidae,
in which zooids, with gonads and heart in a
posterior abdomen, have internal longitudinal
branchial vessels reduced to simple papillae
(Ritterellaspp., Protopolyclinum and Polyclinum)
or lost altogether.

Occasionally (in Tylobranchion) there are
forked branchial papillae rather than continuous
internal longitudinal vessels. However, the
reduction of internal longitudinal vessels to forked
papillae appears to be a genetic character

THE AUSTRALIAN ASCIDIACEA 2 25

indicating a taxonomic difference rather than an
intraspecific variation as C. Monniot (1969a)
suggested when he proposed the synonymy of
Rhopalaea nordgaardi Hartmeyer, 1922 with
Tylobranchion — a proposal earlier rejected by
Arnback (1927).

Rhopalaea and Pseudodiazona Millar, 1963a
(monotypic) are the only Diazonidae represented
in Australia. Others known are Diazona Savigny,
1816 (polytypic), Svndiazona Oka, 1926 (poly-
typic) from the Philippines, Japan and French
Polynesia, and Tylobranchion Herdman, 1886
(monotypic) from the Antarctic (see Kott 1969).
Even genera at present known polytypic are not
diverse, Diazona has 3 species — 2 from the
western Atlantic (see Van Name 1945) and the
type D. violacea Savigny from Europe. Rhopalaea
contains 7 species (see below) and Syndiazona has
only 2 species from the western Pacific.

Syndiazona chinensis Tokioka, 1955 is known
from the East China Sea (Tokioka 1955a), the
Philippines (Millar 1975, and new records QM
GH521 GH531), the Kei Is (Millar 1975), and
French Polynesia (> Rhopalaea piru Monniot and
Monniot, 1987; see below, Rhopalaea). Millar
(1975) thought that Polycitor renziwadai Tokioka
1952 from the Arafura Sea also may be a specimen
of this species. However, Tokioka did not observe
a posterior abdomen or internal longitudinal
vessels, and his specimen has fewer rows of
stigmata than are found in S, chinensis. It therefore
seems more likely that P. renziwadai is correctly
assigned to the genus Polycitor. Nevertheless,
despite the present absence of records, it is not
unlikely that S. chinensis will be found to occur
in Australian tropical waters as it already is known
to range widely in the western tropical Pacific.

Key To THE GENERA OF DIAZONIDAE
(* not recorded from Australia)

1. Zooids solitary or at most 2 embedded in

COMMON TOSts....,.s0deversderesrscdspsred! Rhopalaea
Zooids numerous, never solitary, partially or
completely embedded in common test....... 2

2. Zooids partially embedded in common
MESta crteetsheeeeeavhs ibs cagsteh ede cunsntgind sare Diazona*
Zooids completely embedded in common
TEETH fecdestneranoasshocp oueanh one ssechoorochedeqiessaboseqety 3

3. Muscular extension containing gonads present
posterior to the abdomen ...........eeeeeeerseee 4

Muscular extension containing gonads not
present posterior to the abdomen....,............

seed ge cae catlepe is bealfvattesben ya cyhvesurapianaas Syndiazona*
4. Heart halfway down the posterior
ADA OEM eo. oreo swan space en teces Tylobranchion*

Heart at the posterior end of posterior
ADdCOMEN............ccccceeseeeeeeeeee Pseudodiazona

Genus Rhopalaea Philippi, 1843

Type species: Rhopalaea neapolitana Philippi,
1843

The genus is characterised by its large pharynx,
with internal longitudinal branchial vessels and
numerous rows of stigmata. The abdomen is
separated from the thorax by a narrow oesopha-
geal neck, and is tightly contained in firm
abdominal test. Numerous longitudinal thoracic
muscles sometimes extend onto the abdomen.

Five of the 7 known species of the genus
Rhopalaea are solitary, viz. R. abdominalis
(Sluiter, 1898), R. birkelandi Tokioka, 1971, R.
crassa (Herdman, 1880), R. tenuis (Sluiter, 1904)
and the type species R. neapolitana. Rhopalaea
nordgaardi Hartmeyer, 1922 from Norway and
R. hartmeyeri Salfi, 1927 from the Gulf of Naples
are the only 2 species found as colonies. Rhopalaea
hartmeyeri, recorded only once, generally resem-
bles R. crassa. Rhopalaea nordgaardi (> R.
norvegica Arnback, 1926) is solitary, or up to 2
zooids enclosed in common test. The mechanism
of replication is not known. Constriction of the
epidermis in the region of the oesophagus (which
would involve endodermal tissue from the
epicardial sacs) is not impossible (Arnback 1927),

No trace of budding has been found in either
R. crassa or R. tenuis in the course of the present
study. Although fairly closely associated individ-
uals are sometimes found, they are never joined,
and seldom in contact with one another. Millar
(1975) described enlarged terminal ampullae in the
abdominal test, and even a differentiated blasto-
zooid ‘attached to the abdominal part of the
parent’ (Millar 1975, p.263). No known mecha-
nism of replication in the Aplousobranchia could
account for the presence of such a bud, which
could be a juvenile settled on the outside of the
test, as in specimens assigned to Rhopalopsis
defecta Sluiter, 1904 (ZMA TU968.2 < Rhopalaea
crassa). Salfi (1928) examined many specimens of
R. neapolitana and could find no buds. He
concluded (Salfi 1928, p.370)

individuals of R. neapolitana show phenomena of
regression and juvenescence ... In the regressive
phase the zooid is destitute of a branchial sac and
connected organs, which will reform by the
regenerative process in the phase of rejuvenescence.
Following the periods of regression and rejuvenes-
cence an entire modification of the external shape
of the individual, and sometimes of the typical
shape of the species, occurs.

26 MEMOIRS OF THE QUEENSLAND MUSEUM

This conclusion is supported by the present
observations on &. cravse in which ycgelabive
growth appears confined to regeneration of lost
parts of the body. especially of the thorax, and
to involve modification of the external shape of
the individual as it does in A. neapolituna. Thus,
in Rhapalaea, vegetative replication appears ta
be at an early stage of development, involving
regeneration of parts of zooids, rather than the
replication of whole zooids, It is, therefore, very
similar to the situation in Ciona, which has the
capacity lo regenerate lost parts wu! the body trom
endodermal epicardial tissue (Hirsehler 1914).
Only in R. nordgaardi has the process evolved
one stage further toward the aplousobranch
pattern — the spontaneous replication of indiyvid-
uals to form a small colony,

Rhopalopsiy Werdman, 1890 was erected for
species (R, fusca, Ro crassa) closely related to
Rhapalaed neapoliiana Philippi, 1843, but without
the minute plications ol the branchial sac that had
been observed in the type species, This has not
been confirmed as a distinction, the minute
plications being a variable character, probably
dependent on the condition of the specimen. Thus
Rhopalopsis is now regarded as a junior synonym
of Rhopalaea,

Rhopalaea piru Monniot and Menniot, 1987
from Tahiti is Wrongly assigned. The single
specimen lor which the species was erected is a
small, irregular colony, The 2ooids have a robust
posterior abdominal extension and longitudinal
muscles extending onto the abdomen in two strong
ventral bands, and from there onto the posterior
abdominal extension. Rhopaluea is only rarely
colonial and then never contains the number ol
zooids found in A. piru. Further, although muscles
continue onto the abdomen in Rhopalaea tenuis,
they do not continue onto a long posterior
abdominal extension, These features together with
others reported for R. piru including Lhe conspic-
wous oviduct Silled with eggs, shallow longitudinal
striations in the stomach wall, ventral longitudinal
muscle bands terminating against the mid-ventral
line, and embedded zooids with their anterior ends
only projecting from the surface are all charie-
teristic of Syndiazana chinensis. Tokioka, 195Sa
— of which Rhopalded pirw is a junior synonym,

Only 2 species of Rhepalaca have been recorded
from Australia, R. crassa with a wide range in
the tropical waters of both the eastern and western
coasts, and #. tenuis, known from many specimens
representing & large population in Torres Strait.
Rhopalaea tenuis is readily distinguished from R,
crassa by its basal vaults of hair-like roots and the

longitudinal museles continuing onto the
abdomen

Rhopalaea crassa (Herdman, |880)
(Fig, 4, Plate Tb.)

Ecteinascidia crassa Herdman, (A80, p, 723. 1882, pe
240),

Rhopalaed crassa, Beneden VHX7, p, Zl). Lokioka, 1953,
p. 210. Millur. 1975, p. 262. Kott and Goadbedy,
1982, p, 506,

Rhopalopsis crassa, Van Name, M818, p, 126,

Ecietnascidia frvea Werdmun, 1880, p. 732: 1882. p. 241.

Rhopalopsy fusca; Beneden, 1887, p. 21 Sluiter, 1904,
p ta

Ciona indica Sluiter, 1904, p. 3 (part. specimen (ram
Station 49 fide Hoshino and Nishikawa 1985),

Leleinascidiq (? Rhepatopsis) sulida Heordman, 06, p.
299,

Rhopalaea sagamiana Oka, 1927b, p. 681,

Rhopalaea macrotherax Tokioku, 1953, p. 212.

? Rhopalopsts defecra Stuiter, 1904, p. 14

Dist mis lion

New Rreorns Western Australia (Houtman’'s
Abrothos, OM G11933, WAM 97.78 Cockburn Sd.
OM 69670), Queensland (Muoloolubah, QM G10143
5 GIIYI2 GII9LS; Wistari Reef, QM G10046 GH4I0S
6; Heron 1, OM G94R9 GO9SS-6 G10036 CGOUKY
G101S0 Gl06S9 G11899 GH8I0 GH958 GH2435
GH3463 GHA781: Swain Reefs, QM GH2436 GH2807;
Saumarey Reef, QM GHEH2811: Lizard 1., QM GH4078.
Philippines (QM GH393 GH40X GH421 GH454 GH477
GH484 GT494 GHSIS GH557),

Perviousty Rrooknnm Indonesia (Herdman 1880;
ZMA ‘TU96K.2 ‘TUI25S Rhupalapsis defecta Sluiter
1904, Millar 1975), Philippines (Van Name 1918, Millar
1975). Sei Lanka (BM 1907.4, 30.3 EE. solide Herdman,
1906). Japan (Oka 1927h, Tokioka 1953, Millar 1975),
Hong Kong (QM (12789 GI2808 Kott and Goodbady
1982).

The species is common in coral reef habitats. It is
especially common at Heron | tram 2 18 20m depth.
Desontelion

ExryrNar Arpraranci Individuals are clon-
gate, up to 6cm long, The thoracic portion of the
body is often 2em in diameter, but the abdominal
portion is usually narrower, The thoracic test may
be delicate and almost completely transparent or
firm and translucent lo opaque. Surface irregu-
larities (that are not present in individuals with
thin transparent thoracic lest) increase as the
thickness and opacity of the test increases.
Variations in condition ol the test may be
associated with age, The test is always opaque
and rough over the abdomen. Posteriorly, the
abdominal lest is expanded and/or extended into
solid outgrowths that help to wedge the individual
firmly into crevices and spaces in coral rubble,
No more than a single 2ooid is embedded in the
test,

27

THE AUSTRALIAN ASCIDIACEA 2

CLE Went OE

a =

NEAdtwess

e-f, thoraces

>

G11912),

Fia. 4, Rhopalaea crassa: a, young individual (QM GI0159); b, aged individual (QM

Scales:

showing musculature (QM G 10144 G9921 G10159 GIOI14 respectively): g. gut loop (QM GI0144).

a-g. Smm.

28 MEMOIRS OF THE QUEENSLAND MUSEUM

Apertures in specimens with delicate thoracic
test are conspicuous when extended. They have
6 prominent lobes and pigment patches between
them. Those with solid. gelatinous thoracic test
have uperturés depressed into the thick test and
so concealed by it, The branchial aperture is
terminal, and the alrigl aperture antero-dorsal.
both directed upwards,

Kott and Goodbody (1982) discussed individual
colour variations. ‘The conspicuous yellow in the
thick thoracic test of apparently older individuals
probably indicates the presence of blood cells
containing vanadium with an organic ligand that
onidises to olive green when specimens are
removed from the substrate (ID. Parry pers,
comm.) Absence of conspicuous colour in both
living and fixed specimens with delicate transpar-
ent thoracic test is probably a result of the
relatively small amount of blood present in the
thin test.

INTERNAL Structure: The thorax is always
delicate and the siphons are short, with evenly
placed circular muscle bands, The thoracic
musculature is primarily longitudinal. Muscle
bands from the branchial and atrial siphons break
up inte @ very fine network of fibres at the hase
of the siphons and join again into 10 to 36 bands
extending, down the thorax, Vhey divide into
branches again across the endostyle. the retropha-
ryngeal groove and across the posterior and dorsal
borders of the thorax, One muscle band always
originates from the intersiphonal region and
divides into ventral and dorsal branches toward
the posterior end of the thorax. Terminal branches
extend across the endostyle and across the retro-
pharyngeal groove respectively. Muscles are not
present on the abdomen.

In one specimen the anterior portion only of
the thorax is strongly contracted and the
Jongitudinal museles appear severed, leaving the
terminal branches (where they cross the borders
of the body) in position, but leaying only traces
of musculature over most of the body wall, In
this specimen the internal longitudinal vessels of
the posterior end of the branchial sac also are
consistently interrupted, The condition of this
specimen is consistent with acute contraction of
muscles, Its appearance conforms exactly with
Tokioka’s (1953) deseription of RAwpalace
miacrathorax.

There are from 2 to 6 stigmata per mesh, 50
ta 100 rows of stigmata, and [rom 40) to 50 fine
internal longitudinal vessels supported on conical
papillae. Irregularities oceur in the branchial sac
In at least two specimens a part of several rows
ol stigmata curve to he longitudinally and some

unperforated membrane and irregular interstitial
meshes are present in their vicinity. Ln same
specimens from Mudjimba (QM GI0144) the
internal longitudinal vessels are interrupted
between the papillae and the stigmata are small
and oval, These thoraces may he regenerating.

The abdomen is tightly enclosed in almost solid
test und is only removed with difficulty, The
ocsophagus is usually fairly long, and expands inty
w rather rectangular stomach half way down the
abdomen. It is smooth externally. but internally
the lining is broken up into about 30 distinct fine
jongitudinal ridges that become irregular only on
the dorsal part of the right side of the stomach.
The rectum extends anteriorly to open in the
anterior third of the peribranchial cavity. Uhe anal
border is broken into about & rounded lobes
Minute male follicles cluster argund the large
ovary in the gut loop, posterior to the stomach,
Sometimes the abdomen is especially small and
may be regenerating. A short vessel extends from
the end of the abdomen. It branches in the test,
and its terminal ampullac are present in the root-
like projections of the lest.

Remarxs: The different appearance of speci-
mens with delicate thoracic test and those in which
(he thoracic lest 8 Opaque and irregular, like that
covering the abdomen, is pronounced, [i is
probable that, following loss of the thorax, the
test closes and the new thorax regenerates. within
it. This Would explain the extreme irregularity,
especially in the orientation of the thorax in these
opague. and presumably older specimens, It is a
phenomenon also observed by Salli (1928 p. 370)
for R. neapoltrana in which there is ‘an entire
modification of the external shape’ (see Rhopalaca
ahove).

Paratypes of Rhopalopsis defecta S\uiter, |904
(ZMA TU968.2 Station 310, TU 1258 Station 240)
ure not separable Irom the present species, The
specimens from Sifoga Station 240 included a
group of 3 one attached along the abdominal stalk
and another near the base of the third individual,
appearing asa colony, The thoraces of a number
of these specimens are relatively small, apparently
regenerating within firm test continuous with and
of the same firm consistency as the abdominal
test.

Jo Austrahan populations irregular, opaque
yellow individuals as well as those with transparent
thoraces have been taken from Mooloolabah and
Houatman'’s Abrolhos, as they were from Hong
Kong (Kott and Goodbody 1982). However,
specimens with delicate transparent tests are most
often taken from coral reef locations — unly one,
Opaque-yellow specimen is recorded from Heron

THE AUSTRALIAN ASCIDIACEA 2 29

Ll. (QM GH3463). Perhaps predation occurring in
coral reef habitats prevents individuals surviving
until the thoracic test becomes thick and opaque,
The thorax is missing entirely from a specimen
(QM GH2436) from the Swain Reefs.

In addition to yellow, probably associated with
intracellular vanadium, both blue and pink
individuals have been recorded. One pale blue
specimen was taken from the eastern end of Heron
1., while populations. of this species in the
Philippines and Indonesia are a brilliant sapphire
blue, as recorded for Rhopalopsis fusca Sluiter,
1904. This colour probably results from concen-
trations of tetrapyrols similar to those causing blue
in Sigillina cyanea (pers. comm. D. Parry). A
similar colour is present also in R. neapolitana
and R. hirkelandi, \ts phylogenetic significance
is not understood.

Neither morphology nor colour — both showing
considerable variation and overlap — can readily
separate most of the known species. Some
differences exist in the ayerage number of
longitudinal muscles, or number of rows of
stigmata, or the size of the abdomen, but they
usually do not fall outside the range recorded for
R. crassa. Rhwpalaea abdominalis (Sluiter, 1898)
Trom the western Atlantic (see also Van Name
1945, Monniot 1970) is pink to violet-pink in
preservative and has fewer rows of branchial
stigmata (40) and generally fewer stigmata per
mesh (2) than R. crassa. Rhopalaea birkelandi
Tokioka, 1971 from the Pacific coast of South
America is deep blue in preservative and has a
small abdomen, Specimens of R. neapolitana
Philippi, 1843, from the Mediterranean (BM
98.5.7.303, AM G4271) and the Adriatic (BM
98.5.7.308) are also blue in preservative and have
a relatively large number of longitudinal muscles
(about 36). Rhopalaea hartmeyeri closely resem-
bles R. neapolitana, but is distinguished by its
colonial habit.

Rhopalaea tenuis (Sluiter, 1904)
(Fig. 5)
Rhopalopsis tenuis Slurter, 1904, p.15.

Distrinution

New Recorps- Queensland (Torres Strait, QM
GH4669-74),

Previousty Recorpre: Indonesia (Java Sea —
Sluiter 1904).

The 5 Siboga specimens were taken ut 82m. The new
records represent numerous specimens taken by dredge
between 9°39’ and LO? 03'S and 142°39° to 142°S51°E at
11 to 18m.

DESCRIPTION
ExTerRNaAlt APPEARANCE: Individuals are soli-

Fic. 5, Rhopalaea tenuis (QM GH4669): a, whole
individual; b, abdomen showing gul loop, ovary. and
muscles from dorsal surface; ¢. posterior end of
abdomen showing muscles from left side. Scales: ae,
5mm; hb, 2mm.

30 MEMOIRS OF THE QUEENSLAND MUSEUM

tary, finger-like, upright and up to 6cm long. The
(horacw test (upper hall Lo one-third) is delicate,
and in newly recorded specimens the thorax is
rather mutilated and drawn out, looking rather
like a ragged piece of string. The posterior half
to two thirds af the test i firm and translucent,
with some circular. horizontal wrinkles on the
surface, The pinkish abdomen is seen embedded
in the upper hall of this stalk-tike part of the test
and blood vessels extend through the lower half,
Basally the test is produced into a mass of short,
branched root-like structures to Which sand
adheres, sometimes lorming a rounded, sandy
hold-fast at the posterior end of the body.

The apertures are on short siphons close
logether, on the anterior free end of the body,
The delicate test of the thorax 1s produced into
6 rounded Jobes around each aperture. The
branchial siphon sometimes {s turned ventrally,
although the thoracic test of the present specimens
is usually too mutilated and crushed to determine
the actual orientation of the apertures.

In these preserved specimens there is sometimes
w trace of reddish pigment in the text, and there
are yellow lines along cach siphon alternating with
\he lobes around each aperture,

INTERNAL Stave ruRe: Zooids are delicate wah
a relatively large and diaphanous thorax and a
slightly longer abdomen. The club-shaped abdo-
men has a narrow oesophageal neck which is about
the same length as the swollen, rounded posterior
end of the abdomen which contains the stomach
and gonads.

The narrow thorax tapers posteriorly. It has
about 20 fine longitudinal tnuscles, about half
(rom the branchial siphon and half from the atrial
siphon. These continue as a band along each side
of the abdomen abruptly converging posteriorly
before terminating in a flat disc, one cach side
of the mid-dorgal ling just anterior to the origin
ot the test vessel, No transverse muscles were seen

At the base of the branchial siphon are about
24 fine pointed tentacles, the largest ones
alternating with the smaller ones. The flask-shaped
neural gland has a short, wile duct with a simple
circular opening.

About 12 internal Jongitudinal vessels on each
side of the branchial sac extend the length of the
sac and ave supported by papillae. There arc no
secondary papillae, Uhere are about 60 tows of
stigmata and about 4 stigmata per mesh.

A simple, vertical gut loop is firtnly embedded
in the test with the relatively small, Oval stomach
(sometimes stretched Vertically) about half-way
down the descending limb, The stomach has a
suture line but folds were not detected. ‘I'he anus

opens about two thirds of the way up the branchial
sac. A long tubuleur ovary and numerous male
follicles are crowded into the gut loop.

The posterior abdominal test vessel branches
in the stalk and the terminal branches extend into
the basal rootlike projections.

Remarks. Generally these present zooids
conform with the deseription given by Sluiter
(1904),

Sluiter thought individuals possibly were joined
together by a basal stolon. However, enough
individuals exist in the present collection to
establish this does not happem the species is a
solitary one. All Rhopalaca have the same narrow
waist and their abdomina firmly bedded in solid
basal test, however, the branches of the posterior
abdominal vessel, and the basal roots of the
present Species are distinctive. Muscle bands occur
on the abdomen in Rhopalaea nordgaardi (see
Arnback [927), but not in R. crassa or R,
neapolitana Rhopalaea cencis 1% further distin-
guished by its very much narrower thorax, and
fewer thoracie muscle bands and stigmata.

Abdominal muscles, with their circular terminal
disc, appear similar to those of the colonial
Svndiazone chinensis Vokioka 1955a from the Kei
Is, the Philippines and the East China Sea (see
Millar 1975).

Genus Pseudodiazona Millar. 1963

Vype species; Pseudodiazona sabulasa Millar,
19634 (< Protapolyelimuam clavifarme Kott, 1963).

This rarely encountered diazonid genus is
charuclerised by the presence of 4 long posterior
abdomen containing epicardium, gonads and, at
the posterior end. the heart. It has the diazonid
characters of internal longitudinal branchial
vessels, 6 branchial and 6 atrial lobes, and the
anus opening anteriorly at the base of the antero-
dorsal atrial aperture. Stomach is smooth. and,
possibly 48 an artifact of its preservation, it
sometimes is compressed into » quadrilateral
Shape in section, Longitudinal muscle bands
extend the length of the zooid, from the siphors
to the end of the posterior abdomen. Zooids are
completely embedded in common test,

A posterior abdomen (present in this genus and
in Tylehranchion) suggests an affinity with the
Polyclinidae, Kott (1963) accordingly included 4b
in Prorapolyclinum Millar. 1960 (Euherdmanii-
nae) by expanding Millar's delimtion of Prasi-
polyclinum to include species with complete
internal longitudinal branchial vessels as well as
those which had only remnants of those vessels

THE AUSTRALIAN ASCIDIACEA 2 3]

in the form of papillae on the transverse vessels
(as in the type species P. pedunculatum Millar,
1960 from New Zealand). Later in the same year
Millar (1963a) described Pseudodiazona sabulosa,
in the family Diazonidae on the basis of its
complete internal longitudinal vessels, and close
relationship to the Antarctic Tylobranchion —
which also has a posterior abdomen.

Millar did not comment on the similarity of
his species to Protopolyclinum claviforme Kott,
with which it is here considered to be conspecific.

Pseudodiazona has affinities with Euherdma-
niinae through Protopolyclinum pedunculatum.
The latter species resembles Psewdodiazona
claviformis in the shape of its body, and the course
of the muscles. Further, although Protopolycli-
num peduncularum lacks the internal longitudinal
branchial vessels of Pseudodiazona claviforniis,
their rudiments are present as branchial papillae.

Patridium Kott, 1975 originally assigned to
Euherdmaniinae, characterised by its internal
longitudinal vessels and folded stomach, is a junior
synonym of Pseudodiazona, the stomach folds
being artefacts,

In addition to the type species, one other,
Pseudodiazona abyssa Monniot and Monniot,
1974 from the eastern Atlantic, has been described.

Pseudodiazona claviformis (Kott, 1963)
(Fig. 6. Plate Id)
Protopolvclinum claviforme Kott, 1963, p. 72.
Pseudodiazona sabulosa Millar, 1963a, p.718.
Patridium pulvinatum Kott, 1975, p.4.

DistTRiBUTION

New Recorops:; South Australia (Seacliff Reef, QM
GH2307). Victoria (Off Cape Howe, ZMC 30.9.14),. New
South Wales (Jervis Bay, QM G10100; Botany Bay, AM
Y¥2149).

Previousty Recorpen: South Australia (Northern
Great Australian Bight SAM E1035 holotype
Patridium pulvinatum Kott, 1975), Victoria (Port Phillip
Bay — BM 85.11.20.34-43 Millar 1963a; Eden — Kott
1963),

The species has been taken on rocky substrates at
depths of 10 to 100m.

DESCRIPTION

ExrerRNAL APPEARANCE: One colony (SAM
E1035 holotype Patridium pulvinatum) is a large
(6cm long) gelatinous, egg-shaped, sessile cushion
with some sand on its base. Other colonies are
top-, fan- or club-shaped, sometimes with a firm
sandy stalk or basal part, and a soft, glassy
transparent head wider than the stalk and either
rounded or flattened across its upper surface.
Sometimes the transparent head of the colony is
subdivided into a number of separate lobes of

different diameter, and sometimes the whole
colony is subdivided, the parts joined at the base
of the stalk. Stalked heads are up to 3cm in
diameter. Zooids are seen clearly through the
glassy test of the top of the colony. Branchial and
atrial siphons open separately to the surface by
6-lobed apertures.

INTERNAL STRUCTURE: Zooids are | to 4cm
long. They are divided into thorax, abdomen and
posterior abdomen, the latter being up to two-
thirds of the total length. Relatively short vascular
appendages (2 or 3) extend out into the test from
the posterior end of the posterior abdomen which
often is thread-like, but sometimes is drawn up
into a broad sac. The branchial aperture is in the
centre of the anterior end of the zooid, while the
atrial aperture is antero-dorsal. A circular area
of the anterior prebranchial body wall surrounding
the apertures is white and opaque in preservative
and is highly contractile.

The body wall is delicate and quite transparent.
Body muscles are longitudinal, about 10 thoracic
bands extending posteriorly along each side of the
abdomen and posterior abdomen but not onto
the vascular appendages. Longitudinal muscle
bands branch and bundles of fibres join adjacent
bands, to form a wide open and irregular network
on each side of the thorax. Commissures between
longitudinal muscles alter spacing of the longi-
tudinal bands. In some contracted zooids the
bands are evenly spaced, extending more or less
parallel to one another. In others, muscle bands
curve in an arc from the anterior end, posteriorly
along the ventral border of the thorax and then
dorsally, where they are crowded together before
extending onto the abdomen, In this latter
condition, the dorsal border where the muscles
are crowded together is strongly contracted and
more or less concave while the ventral border is
not and extends out in a wide convex arc.

The branchial sac has from 17 to 22 rows of
stigmata, with up to 20 per row. About 20 internal
longitudinal branchial vessels are supported .on
short papillae which do not project above the
internal longitudinal vessels. The narrow oesopha-
gus opens into a long stomach about halfway down
the abdomen. The stomach is smooth externally,
but internally its glandular epithelium has
longitudinal and irregular interruptions. There is
a duodenal area distal to the stomach and a
conspicuous oval posterior stomach in the
descending limb of the gut. The rectum extends
anteriorly to the base of the atrial siphon.

Gonads consist of numerous male follicles and
a relatively large ovary. A large number of eggs
are sometimes arranged in a single series in the

tw
rm

MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 6. Pseudodiazona elayiformis: ash, two views of the one colony (SAM E1035): ¢. thorax (SAM E1035):
d. whole zovid. with gonads (ZMC); &. whole zovid without gonads (SAM E1035); fg, stomach, and posterior
end of the gut loop (SAM E1035). Scales: a,b, 5mm; c,e-g, 0.5mm: d. }mm,

THE AUSTRALIAN ASCIDIACEA 2

oviduct. In the relaxed posterior abdomen male
follicles are arranged serially. However, when
contracted, they are bunched anteriorly (ZMC
30,9, 14),

Remarks, Generally, examination of the newly
recorded specimens confirms the earlier deserip-
tions. Although Millar (19634) has not recorded
the rather conspicuous branching of thoracic
muscles. his specimens have the same numbers
and arrangements ef muscles. branchial and atrial
siphons, rows of stigmata, inner longitudinal
branchial vessels, the same stomach lining,
anteriorly situaled anus, and similar colonies with
a glassy transparent and expanded head through
which the embedded zooids can be seen.

The species most closely resembles the Antarctic
Tylobranchian speciosum (see Kott 1969),
differigg principally in the position of the heart
al the end of the posterior abdomen.

Re-examination of the holotype of Puirdium
pulvinatum Katt, 1975, has shown its zo0ids to
be identical with those of the present species, I
has the same body proportions. musculature.
branchial sac and the same contractile area around
the siphons, which, in contracted specimens,
flattens the anterior end of the zooid. Kott (1975)
completely misinterpreted the stomach structure
in these zooids. reporting the stomuch as having
folds. In facet. the stomach is the same as that
in other specrmens of Pyewdodiazona, being
basically smooth, but may become folded in some
ot the preserved 7zooids, The colony of Kott’s
(1975) species ts large in comparison with recorded
specimens of P. elaviformtis. However, in a
specimen lot (GH2307) from St Vincent Gulf a
reduction inthe length of (he stalk occurs as colony
size increases. The soft top af the colony appears
lo overzrow the stalk — w trend that probably
culminates in large sessile colonies such as the one
from the Great Australian Bight (SAM F 1035).

Millar (1963a) noted the strong similarity
between the present species and Mamwendisrama
longigona Tokioka, 1959 from Japan. The
colonies are the same with a sandy basal portion
and a soft upper ‘corona’ or head, Although
Vokioka bas not described muscles on other parts
of the body. the arrangement of the thoracic
muscles in his specimens is similar to that in the
present species. The anal opening (opposite the
fifth row of stigmata: Millar 1963a), as in all
diazonids is well anterior near the base of the atrial
siphon, and there are ocelli in the lobes of the
utrial siphon (overlooked in the branchial
siphon?). Another point of similarity is the large
number of eges serially arranged in the oviduct
— acharacter observed in the two other specimens

‘oa
Led

in which gonads are developed (Kot 1963, and
in the newly recorded specimen from Cape Howe
— ZMC 30.9.14). However, Tokioka’s Japanese
species, even if it is found to be a diavonid species.
seems more robust than the present species from
Australia, and his more thoracic muscles. Further
the two species are separated from ope anothers
by the tropics,

Family CLAVELINIDAE Forbes and Hanley,
[64k

The family contains solitary and colonial specics
with sooids ranging from the small (less than bern
long) zoaids of Clavelina minuta Tokioka, 1962
with only 4 rows of stigmata. up to large (100m)
diavonid-like zooids (c.g. C. mericdionalis, C.
ostrearium and others) with very numerous
branchial stigmata, Although replication always
occurs, some species have solitary sooids while
others reflect different degrees of organization.
from irregular colonies with separate or partially
embedded zooids connected by basal stolons or
basal tesi. Lo completely embedded couiuls
regularly arranged in regularly shaped. stalked
colonies (Clavelina haudinensixs. C. pseucduhaneli-
nensix and the genus Nephttieis).

Faniilial characteristics are smooth bordered
apertures opening separately lo the exterior
absence of internal longitudinal branchial vessels;
wide horivontal membranes between the rows of
stigmata; and a Well developed posterior abdom-
inal vascular stolon with mesenchymal septum,
The vascular stolon branches in the basa) test,
and the terminal branches end in ampullae fram
which. usually following their enlargement and
isolation from the vascular stolon (Berrill [935b,
{950}, vegetative vooids develop. In some solitary
species clones separate fram one anotherand from
parental vooids following their formation (e.g.
Clavelina miniata Watanabe and Tokioka, 1973).
In others the adult zooid is resorbed and new
zooids develop from the isolated terminal
ampullae that persist in the stalk. Thus in the
former case clones exis! Contemporaneously and
in the latter case they exist sequentially. Only in
the venus Nephiheis is the vascular apparatus
modified. In this genus it forms a complicated
network in the stalk, The site of replication ts
localised at the top, rather than at the hase of
the stalk and the terminal ampullae are not isolated
from the network al any stage of the replicative
process.

As in Diazonidae, the lest is translucent and
gelatinous, and the body is divided into thorax
and abdomen. the latter occupied by the vertical

34 MEMOIRS OF THE QUEENSLAND MUSEUM

gut loop. Post-mortem colour changes resulting
from oxidation of high levels of intracellular
vanadium usually result in dark blue zooids.

Body muscles of the Clavelinidae are grouped
into longitudinal and oblique bands. The more
ventral bands are oblique, extending from the
endostyle (rather than from the branchial siphon)
toward the postero-dorsal corner of the thorax,
where they extend along the abdomen. More
dorsal bands are usually longitudinal, extending
from the branchial siphon, the intersiphonal
region, and, sometimes from the atrial siphon,
onto the abdomen. Sometimes muscle bands from
the branchial siphon, the intersiphonal region and
the endostyle extend to the dorsal border of the
body where they appear to fade out as they turn
posteriorly, apparently not extending onto the
abdomen. These are described below as transverse
muscles, although their provenance, from the
primarily longitudinal and oblique musculature of
the Clavelinidae, is clear. In relaxed thoraces,
muscle bands subdivide into separate bundles,
exchanging branches with one another, In
contracted thoraces these branches draw the
separate bundles together causing an apparent
decrease in the number of muscle bands resulting
in apparent intraspecific variation in the numbers
of muscle bands recorded for each species. In the
descriptions that follow, the formula developed
by Tokioka and Nishikawa (1976) has been used
to describe the musculature of clavelinid species.
E refers to muscle bands extending from the
endostyle, B to muscle bands from the branchial
siphon, D to muscle bands from the intersiphonal
space between the branchial and atrial apertures,
and A refers to muscle bands from the atrial
siphon. In species with largely longitudinal
muscles, the thorax becomes short and wide with
their contraction. Where muscles are primarily
oblique, their contraction causes distortion of the
thorax, drawing the branchial siphon and
endostyle down leaving the atrial siphon at the
top of the zooid. Zooids with transverse muscles
become long and narrow when contracted.

The length of the abdomen relative to the thorax
varies from species to species, although the
stomach is usually at its posterior end. The anal
aperture is some distance up the branchial sac as
in the Diazonidae.

Gonads are present in the posterior end of the
gut loop. Eggs are relatively large and numerous
(larger than in Diazonidae). The large eggs
protrude from the ovarian wall and are rather
loosely grouped together amongst the male
follicles. The testis consists of numerous pear-
shaped follicles, surrounding the ovary and

spreading onto the gut wall. In some species
fertilisation takes place in the peribranchial cavity
where development proceeds. In others, fertilisa-
tion is in the distal end of the oviduct, which duly
expands and protrudes from the posterior end of
the thorax to form a brood pouch in which
embryos begin development completing it in the
peribranchial cavity before their release as tailed
larvae.

Most larvae have a large trunk (0.7 to 1.5mm
long), usually with 3 large, triradially arranged
adhesive organs, one dorsal and 2 ventral, at the
anterior end of the trunk. The adhesive organs
are on short, wide stalks and usually consist of
a shallow cup of epidermal cells containing a wide
but fairly shallow protruding cone of columnar
cells. These increase in length toward the centre
to form the cone. Occasionally the epidermal cup
is absent (Clavelina baudinensis), and in several
species the adhesive organs are much modified
(see C. dagysa). The adhesive organs are supported
on a stalked frontal plate. The stalk of the frontal
plate is horizontal, extending from the posterior
abdominal end of the oozooid. The plate is more
or less flattened and stands vertically against the
anterior end of the oozooid. Frontal plate and
stalk, together with the developing oozooid, are
all in the larval trunk and enclosed by test. An
otolith and an ocellus are in the cerebral vesicle.
Usually the tail encircles the trunk around the mid-
line. Anteriorly it passes up between the 2 lower
adhesive organs and to the right of the upper one.
Two, 4, or more, rows of stigmata develop in larvae
before their liberation, However the gut loop is
only partially differentiated and completes its
development after larval release.

Despite the general similarity of clavelinids and
diazonids, a cionid-like ancestor is most likely for
Clavelinidae, for in Ciona a similar mesodermal
septum develops in the posterior abdominal
vascular stolon (Millar 1953a) and in some cases
the stolon itself is well developed (e.g. in Ciona
intestinalis longissima and C. intestinalis gelati-
nosa: see Van Name 1945). In Diazonidae the
posterior vascular stolon never has a mesodermal
septum, and an origin from some _ pre-cionid
ancestor, through exploitation of the regenerative
capacity of the epicardium for replication is
possible; while Clavelinidae exploited the mesod-
ermal septum of Cionidae for the same purpose.

Pycnoclavella Garstang, 1891 and a new
monotypic genus Euclavella (type species Colella
claviformis Herdman, 1899) are separated from
Clavelinidae by their invaginated, tubular, larval
adhesive organs. This suggests a different origin,
but probably also from a cionid ancestor. These

THE AUSTRALIAN ASCIDIACEA 2

genera are further distinguished from Clavelinidae
by their smaller zooids, fertilisation at the base
of the oviduct, smaller gonads, and probably a
different method of replication — viz. horizontal
division of the abdomen (see below). Stomozoa
Kott, 1957b, also previously thought clavelinid,
has many characters separating it from this family
(see below, Stomozoidae). Archiascidia Julin,
1904, from the Mediterranean, previously thought
a monotypic clavelinid, is probably a synonym
of Pyenoclavella.

Only 2 genera of the Clavelinidae are recognised
in the present work, viz. Clavelina and Nephtheis,
separated from one another by the vascular
network in the latter. Records of Nephtheis
(monotypic) are at present confined to the tropical
western Pacific. Clavelina, a relatively diverse
genus with a cosmopolitan range is well repres-
ented in Australian waters. Records of the family
from the Antarctic are confined to a single zooid,
probably in the genus Clavelina (see Kott 1969,
Podoclavella sp.); and affinities of Australian
representatives of the genus are probably with the
tropical fauna.

Genus Clavelina Savigny, 1816.
Type species: Ascidia lepadiformis Mueller, 1776.

The genus is here defined as comprising solitary
or colonial species of the Clavelinidae in which
the zooids are connected by basal stolons, or
completely or partially embedded in common test.
The thorax is large with not less than 4 rows of
stigmata and not less than 20 stigmata per row.
Posterior abdominal vascular stolons branch but
do not form a network. Replication is from
isolated terminal ampullae of the vascular stolon
in the basal test. Eggs are fertilised and begin
development in the distal part of the oviduct which
is enlarged to form a brood pouch at the postero-
dorsal corner of the thorax or in the anterior part
of the abdomen; and they continue their devel-
opment in the peribranchial cavity.

Savigny (1816) defined this genus as having a
stalked body, branchial and atrial openings
without lobes, with neither folds nor papillae in
the branchial sac, with languets on the dorsal
lamina, and with an abdomen containing the gut
loop and ovary posterior to the thorax. Milne
Edwards (1842) added its capacity to replicate to
the generic definition, This generic definition is,
in fact, a recitation of family characteristics.
Clavelina, as defined, includes a wide range of
forms from the solitary zooids of C. meridionalis
to massive colonies,

The type species, Ascidia lepadiformis (Mueller,

ioe)
Ww

1776), has, in addition to other clavelinid
characters, separate zooids arising from common
basal test. Podoclavella Herdman, [890 was
subsequently erected to accommodate solitary
species such as Clavelina meridionalis; and
Stereoclavella Herdman, 1890 accommodated
species such as C. australis with separate zooids
but with the basal test forming a solid mass or
common stalk. Synclavella Caullery, 1900, was
erected to accommodate clavelinid species in
which the zooids were completely embedded.

Subsequently Van Name (1945) and Berrill
(1950) drew attention to the difficulty in separating
genera on the basis of the degree to which their
zooids were separated, a view with which the
present author is in agreement.

Huus (1937) separated Podoclavella and
Clavelina on the basis of the presence of structural
ridges on the stomach in the latter genus. However,
again, the attempt to subdivide the genus was
unsatisfactory and probably invalid — Clavelina
lepadiformis has a stomach that is rectangular in
section but there do not appear to be any structural
ridges. Nishikawa and Tokioka (1976, p. 63) in
a review of some clavelinids in Japanese waters
observed, that ‘the feature of the stomach seems
to differ considerably according to the physiolog-
ical state of the zooids’. In the present study, the
presence of structural ridges in the stomach is
variable in Clavelina meridionalis, C. moluccensis.
and C. robusta n.sp.

Accordingly there does not appear to be any
justification for the subdivision of Clavelina as
originally defined either on the basis of its stomach
or the degree to which its zooids are free or
embedded. Accordingly Podoclavella, Stereocla-
vella and Synclavella as well as Chondrostachys
MacDonald, 1858 are regarded as junior syn-
onyms of the genus.

Of the 14 species of Clavelina recorded from
Australia, C. australis, C. baudinensis, C.
cylindrica, C. dagysa, C. mirabilis, C. ostrearium,
C. pseudohaudinensis and C. nigra n.sp. are
indigenous Australian species and are all temper-
ate. Clavelina arafurensis, C. fecunda, C. moluc-
censis, C. meridionalis, C. robusta n.sp and C.
oliva n.sp. are tropical western Pacific species,
although C. moluccensis has a range into
temperate Australian waters.

The genus is not known from the Antarctic and
the affinities of Australian species are with tropical
taxa. Australian indigenous species are temperate,
but they have recognizable phylogenetic affinities
with tropical, possibly sister, species — viz.
Clavelina australis with C. robusta; C. cylindrica
and C, nigra n.sp. with C. moluccensis;, C. dagysa

36 MEMOIRS OF THE QUEENSLAND MUSEUM

und C. ostreariun with ©. pliva asp. Generally,
the species appear to be prolific. the large zooids
incubating large numbers of embryos. When
liberated, the larval trunk ts large and both adult
organs and adhesive apparatus are well developed
hut the tail does not suggest a strong swimming
capability. Lack of dispersal may explain the high
level of speciation evident in Australian temperate
waters.

Kiv ro um Specs or Char pe.iya
RECORDED FROM AUSTRATIA

1. Colonial, the colony regular and rope-like;
a short narrow cylindrical neck separates

each zooid from the comnion test mass ,
oer: Poop pgett 434. eyliotedricar
Colonial or solitary. colonics not regular and
rope-like, no short, narrow. cylindrical
néck separates zooids from the common
Test MASS ....,5- 005-5 +2
Zovoids partially or completely ‘trabediled in
common test . vate’: riterietehiele regen
Zooids solitary ot “imited only by thin vaseular
SEOMWIS- hae aie dee hee eee eh och cap ee oe 4
3. Zooids not almost completely embedded (at
least whole of thorax projecting).......7
Zooids almost completely embedded (not
more than anterior part of thorax
projecting) .... 12
4. Zooids long, extending to base of stalk:
vascular appendages short ............5
Zooids long of short, never extending to base
of stalk; vascular appendages long ..... 6
5. Stalk thin and leathery ......C, ostrearium
Stalk not thin and leathery ,.....C. dagysa
6, Trawsverse muscles present anteriorly:
oblique muscles posteriarly ...... 0.0...
yeh Peels Re hueh a: C. mericdionalis
Transverse muscles not present anteriorly:
muscles longitudinal and oblique ...... .
Weravers (as STE eurisiess Te C_ oliva sp.
7. Thoraeie musctes all transverse: muscles
inconspicuous on the abdamen ........ 8
Thoracic muscles not all transverse; muscles
conspicuous on the abdomen.,
8. Pigment patches in a@ transverse row of
between the apertures .C. moluccensis
Pigment patches. not in a transverse row of
3 belween the apertures....C. Higrd n.sp.
9. Oblique muscle bands < twice the number
of branchial muscles (E<2R). ..C. feeunda
Oblique muscle bands > twice the number

t

ee ee ee es

of branchial muscles (E > 2B) ........ 10
10. Thoraces only free of common test.......-
Bass ae Ba eee veneer nets SMW GTIES

Thoraces and al least part of abdomen free

OL COMUMIOM LESts sss bee es osteo ere ey oe I!
(1. Vhoracic muscles about 10; median pigment
patches alternate with apertures ...... f-
pinch oho ethiele inter atid bila» dads Cc. australis
Thoracie mistles about 20; no median
pigment patches alternating with aper-
ANTES Ie hg see cle cplecs elec ..C. robusta n.sp.

12. Musele bands all longitudinal tie ttt
odie alin eae oye etal Habit . havtdinensis
Muscle bands nat all cane bi3.fa¢ 13
13, Colony a regular mushroom-shape ..-..-.-
a wera ite t's coeen eee €. pseudobaudinensis
Colony not a regular mushroom-shape ....
wie dain dp ose de ealec dines cle C. arafurensiy

In addition to the species already recorded from
Australia, the following have been recorded from
the western Pacific region and may occur in
Australian waters.

Clayelina coerulaea Oka, 1934 trom Japan has
a colony that resembles that of C. wiela, its
zoids being separate and narrowing to their
points of attachment to the basal stolons (see
Nishikawa and Tokioka 1976), Although, tts
musculature penerally resembles that ol C.
maluccensis, having neither oblique nor
longitudinal muscles, jt has a few anomalous
muscles that cross the thorax from the atrial
siphon in the opposite direction to the majority
of the muscle bands. Living, the species is
translucent blue with darker blue bands around
the apertures,

Clavelina cycluy Tokioka and Nishikawa, 1975
from Okinawa and the Philippines (QM GH475)
consists of vooids partially embedded in
common test. with a muscle formula 4F, 8B,
2D (Nishikawa and Tokioka 1976). In life these
vooids ure grey with a white band around the
base of the branchial siphon. Their colour
resembles that of the 7voids of C. nigra n.sp.
The species are clearly distinguished by their
muscles Which, in C. nigra, are all transverse.

Clavelina elegans (Oka, 1927a) from Japan (sce
Tokioka and Nishikawa 1976, and Nishikawa
and Tokioka 1976) has zooids of 2 to 3em joined
by common basal test, with muscle formula 4—
6E, 4B, 2 4D. All musele bands extend along
the abdomen, The species resembles C. feeunda
in its colony and zooid musculature. C. elegans
is distinguished by its larger zooids and larvae
and by the absence of yellow in the living zoids,

Clavelina enormiy Herdman, 1880, from the
western Indian Ocean und South Altica. has
long (Sem) vooids attached to branching stolons
or to a common basal stalk. It resembles C,
ausiraliy, but is distinguished from it by a

37

THE AUSTRALIAN ASCIDIACEA 2

“AILPJOS SPlOOz *S :pappaquia Ajyenjied splooz
“Cg :pappaquia Ajamqua splooz “q, “WUOUTUOD ay) PUNOLe asiMyDOpOUL LAAT aduey, ‘aesadtu9} *9) ‘[eoidosy “17 ‘oyLowd ISAM-OPUT “AAAT YloWd WoIsaAy “AAA ‘SNOUdsiput “y,

sayoied
= é > Zz dr a9 MOTIAA [RIOIE] : Biypelsny “N Wd sisuainfoio “>
soinqiade
uaamjaq sayoied
189} BUIAI] ueIpaw 10 dul] "| MOH
UL SJOP aq YIM 60 ‘, ve do ae 49 anyq asiaasuely 7 pio]-soyjoiqy ary sisuauipnogopnasd *)
7 ¢0 suou Vc C0 d6 40 “ d Aueqry—"T 1S9un0y vv sisuauipnog *)
if é m dé dv A0z7< Z , "] ysaun10y av ‘ds'u pusiu ‘9
samnqiade uaamjaq
aul] asIaasued) "| paezr]
uswopqe 1104s Zl - ae a€ az ul soyoyed anjq ¢ : -Jjny ynowxy ad AI sIsuarINjoul “D
uswopge 110Ys Wodulaysa
“Auojod ayl-adol (aa quasaid dr 401 Jl 7 7 —ABg ylReUS ary DILAPUIAd “>
sainqiade YM
18a} BUIAT] aqeusaye sayoyed Avg U0}aIO Wl
UI SJOP STTYA YIM L‘0 ‘ TZ d@ AL anjq ueipaw 7 Wodusaisa yy, ary syDAIsnD “)
XBIOY} SASSO19
g]ISNU dsJ9ASURI} é F I 8 AZ i : eyelsny yINos ary Te)
a foul ” det dt 48 a “ SoyfoIqy—"] preZr'] Wd ‘ds‘u pisngos \)
[Jews sprooz
‘snojauinu sodiquia 6L0 r de aS AL 4 Sq "| saun0 y-"] UOIdH dM ppundaf “)
‘yory Joidweq
a 01 a Vb dc ds A01 a “ =] Beulspur] VdM ‘ds‘u payo “3
sayoyed “‘youy Jadweq
UO[O}S Ie[NISeA SUOT Ul 7 CZ dZ A07< MOJ[AA [RIOIB] > -Sulyoey Od dM sDUOIpLal *D
¥ Sc'l i CS a0] 402 " 4 “‘yory siAnN-Aueqry ary wunjipaiso *)
Aeg oydeido0an
UO[OIS Ie[NOSeA JOYS C| ouou ade a€ A0z7< anjq pljos S "| sounlo0y ary pstsop -D
uone Bleysny
(uur ‘y3u2]) (Suialy) — -stued10 punose uondiasap
UIQ YUNIDRAIeY —- YORU} sa Saposn J INojoD — AUoJOD¢ asuey, o1ydeiso0aso1g, saisads

VIIVULSAY WOU GACUOOAY VNITAAWT) AO SAlOAdG AHL AO SUSLIVAVH) JO ANVWWIS "OT FTEV 4

38 MEMOIRS OF THE QUEENSLAND MUSEUM

relatively small number of endostylar muscles
(4) and a leathery basal stalk.

Clavelina miniata Watanabe and Tokioka, 1973
from Japan has solitary zooids that separate
from the parent zooid immediately following
replication. The longitudinal and oblique
muscles are equally numerous, distinguishing
the zooids from those of Clavelina oliva n.sp.
which has more oblique than longitudinal
bands.

Clavelina minuta Tokioka, 1962 from Japan has
only 4 rows of stigmata and is clearly distinct
from all other species.

Clavelina obesa Nishikawa and Tokioka, 1976
from Japan and the Philippines (QM GH523,
GH554, GH560) has rather stout zooids up to
2cm that, like C. viola, are attached to basal
stolons. However C. obesa does not have the
tapering stalk of C. viola, it is much smaller
and its muscles are principally transverse,
confined to the thorax. In the latter character
it resembles C. moluccensis but it has fewer
muscles, and in life it is bluish-white without
the characteristic pigment patches of C.
moluccensis.

Clavelina viola Nishikawa and Tokioka, 1976
from southern Japan and the western Pacific
(Nishikawa 1984) forms colonies of zooids (up
to 4cm long) that narrow to basal stolons. The
zooids closely resemble those of Clavelina oliva
n.sp. which, however, is distinguished by its
solitary or near-solitary habit.

Podoclavella polycitorella Tokioka, 1954a from
the Tokara Is and the western Pacific (Nishikawa
1984) has a polyclinid larva (Nishikawa /oc. cit.),
and may be a species of Euherdmaniinae with 8
rows of stigmata.

Clavelina flava Monniot, 1988 from New
Caledonia has thread-like zooids with a long
oesophagus, the anus opening at the base of the
atrial cavity, small ovary, large testis follicles and
embryos developing in the oviduct — all characters
indicative of Pycnoclavella or Euherdmania rather
than Clavelina. Further, the larvae lack the axial
cone of the adhesive organs of Clavelina. They
may have partly everted tubular adhesive organs.
The ocellus is large, and although an otolith is
reported, it is not shown on the figure (Monniot
1988, fig. 3H). Colonies resemble those of
Pycnoclavella arenosa n.sp., with sand adhering
around the common stalk. However, zooids have
more stigmata — 10 to 12 rows instead of the
maximum of 6 (in P. arenosa), the stomach is
folded rather than smooth as in Pycnoclavella,
and the siphons have lobed rather than smooth

rims. Thus, although the species has gonads in
the abdomen, it appears to have closer affinities
with Euherdmania than Clavelina or
Pycnoclavella.

Clavelina arafurensis Tokioka, 1952
(Fig. 7. Plate le.f)
Clavelina (Synclavella) arafurensis Tokioka, 1952, p.97.
Nishikawa, 1984, p. 116.

DistRIBUTION

New Recorps: Western Australia (Exmouth Gulf,
QM GI11987-8). Philippines (QM GH449 GH478).

Previousty Recorpen: Arafura Sea (Tokioka 1952).
Truk (Nishikawa 1984).

The colonies are found under ledges.

DESCRIPTION

ExTerRNAL APPEARANCE: The colonies consist
of lobes containing up to 12completely embedded
zooids extending parallel to one another to open
on the upper surface where they project slightly.
Lobes up to lem high and about 0.5cm in diameter
branch off an irregular, branching, basal stalk.

Fic. 7, Clavelina arafurensis: a,b, colonies (QM G11988
G11987); e, zooid (QM G11987); d, anal border,
opened out and entire (QM G11987). Scales: a,b,
2mm; ¢, |!mm.

THE AUSTRALIAN ASCIDIACEA 2 49

The glassy, upper thoracic portion of each lobe
is slightly wider than the firm, translucent basal
part. Vascular stolons af the zooids extend
through the basal stalk, where new vegetatively
produced zooids graw up into new, vertical zooid-
bearing lobes,

In lite zooids are purple with regular bright
yellow triangular patches on each side of the dorsal
midline between the siphons. The apex of cach
patch is at the side of the atrial siphon, and the
rounded base of the triangle spreads around the
base of the branchial siphon. There may also be
a yellow streak along the dorsal surface.

InvrRNAL Streucrere: Zooids are relatively
small, about O.6em long, of which thorax,
oesophageal neck and posterior expanded part of
the abdomen are all about ane third. Apertures
are on short siphons, the branchial aperture turned
slightly ventrally and the atrial aperture directed
upwards, About [2 muscle bands on the thorax
have formula 6E,4B,2D, These extend along the
abdomen. There are about 32 tentacles in 3
concentric circles with the 8 large tentacles near
the base of the branchial siphon, 8 moderate sized
tentacles in the middle circle. and 16 small ones
in the anterior circle, The neural gland opening
is long and yertical, protruding slightly into the
pharynx.

There are 12 to 16 rows of 20 to 30 stigmata,
The oesophagus is long, prestomach absent. and
the large, roomy stumach is in the anterior half
of the posterior third of the zooid. [It has 4 or
more, Sometimes irregular, rounded folds,
apparently artefacts. A small, oval posterior
stomach occurs helore the gut curves around to
open into the rectum at the posterior end of the
rooid. The anal opening is bilabiste, the mesial
lip with irregular, shallow lobes and the lateral
lip with 2 smooth jobes. Gonads are present in
the gut loop, although the newly recorded
specimens are nol mature. Larvae are unknown.

Remarks: Colonies and zooids, including
pigmentation of the newly recorded specimens, are
identical with those previously recorded from the
Aratura Sea. The species has smaller 2o0ids than
is usual for many species of Clavelina, and colonies
ure less regular than is usual for species with
completely embedded vaoids. The stomach
resembles that of Clavelina oliva tsp. but is
further toward the posterior end of the abdomen,
The arrangement of the thoracic muscles alsa
resembles that in C. alive, however they are nov
so numerous, Zooids and their muscle bands also
resemble those of C. elegans. However. the small
completely embedded zooids and irregular colony
together distinguish this species from all others.

Clavelina australis (Herdman, 1899)
(Fig. 8 Plate 2a—c)
Srereoclavella australis Werdman, 1899, p. 6.
Podoclavelle australis: Kou, W957a, p. 93 (part. specimen
from Port Jackson): 1972c. p. 234: 972d. p. 242.
Not Sevclavella auviralis, Caullery, 1900, p.1419 (7 <
Clavelina pseudobaudinersis),

Disrriguton

New Recorme % Vietoria (Western Port, MV
£53399), New South Wales { Ulladulla, QM GLI9S3: Port
Hacking. AM Y2142 Y¥2145 Y2154-5). Queensland
(Moreton Bay, OM G9250 C2544 G9I256 GH IKI)

Preeviousty Ricomote:. New South Wales (Port
Hacking AM YS8I4 Ker 1972c:, Port Jacksan
holotype AM U132, AM G63. Herdman 1899, Kott
t9S7a)

Deseriprian

Exteasat Appearance. Colomes vary from
top-shaped with a thick stalk. the upper Ice ol
the zovids tanning out from the upper surface of
the stalk in Which the posterior ends of zoids
are embedded; to massive colonies in which the
whole length of the long cylindrical yooids (up
to 4cem) are separale from one another arising from
a basal plate of common test about 4mm thick,
Both sorts of colony have been taken from
Moreton Bay. However, the latter type in which
the Zooids are separate from one another has been
taken only trom Moreton Bay.

Living colonies are always conspicuous. with
yellow to yellowish-blue zooids in transparent Lest
with three large bright blue patches in the median
line — one over the anterior end of the endostyle.
one between the siphons and one posterior to the
base of the atrial siphon. There is @ smaller patch
of bright blue over the anus and white spots on
anterior parts of the test,

INTERNAL Srructure: Zooids are robust, with
a relatively long, narrow oesophageal neck joining
the thorax to the expanded (and often embedded)
posterior end of the abdomen (containing the
stomach, gui loop, gonads und heart), Body
muscles are strong, although not parucularly
numerous, with the formula 7E,2B,2D, They
continue to the posterior end of the abdomen,
those on the left extending around to the ventral
border and those on the right extending dorsally
behind the stomach. There are 12 short, stumpy
branchial tentacles. The vertical slit apening of
the neural duct protrudes slightly into the pharynx.
There are 14 to 18 rows of SO to 75 stigmata
Phere is no prestomach, and the stamach is about
three quarters ol the way down the abdomen, [|
hus a Suture line and sometimes wraps around
each side of the intestine. The anus opens into
the posterior-third of the atrial cavity. Gonads ure

40 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 8, Clavelina australis: a, colony (QM G9253); b, contracted zooid in test (QM GH3890); ¢, extended zooid
(AM Y814); d, larva (QM G9253). Scales: a, 2mm; b,c, 1mm; d, 0.1mm.

THE AUSTRALIAN ASCIDIACEA 2 41

in the gut loop, male follicles, as usual, covering
and obscuring the ovary.

When breeding, up to 100 embryos are present
in a brood pouch that extends across the posterior
end of the right side of the thorax from the postero-
dorsal corner. Embryos complete their develop-
ment in the peribranchial cavity. Colonies from
Port Hacking (AM Y84) in June have embryos
in the brood pouch and atrial cavity in June.
Moreton Bay populations collected in May and
July also have embryos, although those from
Ulladulla in July do not.

Larvae are smaller than is usual for this genus.
The trunk is about 0.7mm long, with the tail
wound about three quarters around it. Sometimes
the tail crosses the anterior end of the larva from
left to right forcing the 2 adhesive organs on its
left upwards and the one on its right downwards.
The frontal plate is well developed, with slight
lobes alternating with adhesive organs. Adhesive
organs have a shallow epidermal cup surrounding
a wide, shallow axial cone.

Remarks: The species is large, with long zooids,
resembling those of the new tropical species C.
robusta n.sp. The species are distinguished by their
musculature, pigmentation and larvae. Larvae of
the present species are much smaller than those
of the new species. The large zooids of the present
species also resemble those of some larger
specimens of C. moluccensis. The longitudinal and
oblique muscles distinguish it, C. moluccensis
having conspicuous transverse muscle bands only.
Clavelina moluccensis can also be distinguished
from C. australis by its transverse row of 3 pigment
patches between the siphons and by its prestom-
ach. Living specimens of C. pseudobaudinensis
have the same white spots in the test as the present
species, although zooids of C. pseudobaudinensis
are completely embedded.

Clavelina enormis Herdman, 1880 from south-
ern and eastern Africa (see Michaelsen 1930,
Millar 1975) has long (Sem) zooids rising from
a common basal mass of test that is sometimes
modified into a common stalk. The species
resembles C. australis in the size and form of its
colony, zooids, larvae and their brood pouch.
However, C. enormis apparently has only about
4 endostylar muscles, and basally the stalk
becomes very leathery, while in C. australis the
stalk or basal test is gelatinous and there are twice
the number of endostylar muscles. Further, the
known range of C. australis suggests that the
species are not conspecific, C. enormis being
recorded only from the eastern Indian Ocean while
C. australis is known only from subtropical to
temperate latitudes off the eastern Australian

coast. Michaelsen (1930) recorded C. enormis
from Oyster Harbour, Albany (Western Austra-
lia), but again the record seems anomalous; the
specimen is probably one of C. moluccensis
(known from Albany).

A single, possibly juvenile zooid, with the
median pigment patches and musculature char-
acteristic of this species, has been taken from
Western Port (Victoria) and could be of this
species, suggesting its range may extend further
south than Ulladulla.

Clavelina baudinensis Kott, 1957
(Fig. 9. Plate 2d)

Clavelina baudinensis Kott, 1957a, p. 87 (part, specimens
from Rottnest I, with small larvae); 1972b, p.166 (part,
specimens from Rottnest I.). Not Millar, 1966a, p.363;
Kott 1972a, p.4 (< C.pseudobaudinensis).

DistTRIBUTION

New Recorps: Western Australia (Rottnest I., WAM
30.75; King George Sound. WAM 22.87),

Previousty Recorpep; Western Australia (Rottnest
I, — holotype AM Y801, paratypes AM YII18 Kott
1957a, 1972b).

The species has been taken from 2 to 12m.

DESCRIPTION

EXTERNAL APPEARANCE: The colonies consist
of mushroom-shaped heads of soft, glassy test,
onto which the zooids open, supported on firm,
sometimes gelatinous, but often hard and leathery,
stalks up to Scm long and | to 1.5cm in diameter.
The lower part of each stalks divides into short
holdfasts or long prop-like branches (WAM
22.87). Sometimes the top of the stalk is divided
so the head of the colony separates into lobes,
Zooids are completely embedded, the test being
only slightly raised over the upper part of thorax
on the upper surface of the mushroom-shaped
head of the colony. Zooids are up to 3cm long,
and quite robust. They extend down into the firm
test at the top of the stalk,

Living colonies are white and translucent with
one blue patch over the endostyle, 3 in a transverse
arc ventral to the base of the atrial siphon, and
a pair (one on each side) behind the base of the
atrial siphon.

INTERNAL StRuUcTURE: The zooid is long and
narrow, with a large roomy thorax slightly longer
than the posterior expanded part of the abdomen
containing stomach and gonads. The oesophageal
neck is long and narrow, occupying about two-
thirds of the total length of the abdomen. Body
musculature is unusual as both dorsal and
endostylar muscles are absent, although there are
2 bands with branches extending along the dorsal
side of the atrial siphon and a branch from one

42 MEMOIRS OF THE QUEENSLAND MUSEUM

of these crosses the intersiphonal area together
with a branch from one of the branchial siphon
muscles. Thus, the muscles are all longitudinal,
with formula OEF,9B,OD,2A. Muscles extend from
the thorax along the length of the abdomen. There
are 6 large, 6 middle-sized and 12 small rudimen-

Pic 9, Clavelina baudinensis: a. colony (WAM 30-75);
b. 001d (holotype AM YSO1): ¢, anal border (holotype
AM YSO1), d, larva (holotype AM YSO1L). Seales: a,
Smm, b, Imm; ed, 0.1mm).

tary tentacles respectively in 3 concentric rings at
the base of the branchial siphon. The opening of
the neural gland is a vertical slit between two
protuberant fleshy lips.

There are 17 to 20 rows of 50 to 60 stigmata.
The oesophagus ts long, and prestoamach absent.
The stomach, in the anterior half of the posterior
expansion of the abdomen, is long and narrow.
It has a suture line, but no other structural ridges
although in section it is more or less rectangular
with one concave side where it lies against and
curves slightly around each side of the intestine.
An oyal, posterior stomach enlargement in the
descending limb of the gut. The ascending limb
is occupied entirely by the rectum, The anal
opening, near the posterior end of the atrial cavity,
is bilabiate and each lip is irregularly lobed.

The ovary contains large eggs, 0.3mm in
diameter. These develop in the atrial cavity, where
they are crowded in some zoaids of the holotype
(collected in November).

Larvae are small, the trunk only 0.5mm and
the tail completely encircles it, Adhesive papillae
lie triradially, each a group of modified ectodermal
vells on the end of a short stalk projecting from
a short frontal plate at the anterior end of the
larval trunk,

Remarks, Kort (1976), in deseribing C. psew
dobaudinensis, refers to colonies of the present
species containing the characteristic small larvac,
from Laverton Bay, This is an error ~~ there are
no colonies of C. bauedinensis from that location.
Recards of the species are confined to the south-
westem comer of western Australia from Rottnest
1. to King George Sound, and apparently the
species is indigenous to that area. The species can
be distinguished from C. pseudohaucdinensis
which has a similar colony — by its unique thoracic
muscle formula, distinctive arrangement of blue
pigment patches, and its small larvae. There is
no other species that completely lacks endostylar
muscles, allhough C. fecunda has very tew.
Nevertheless, this does not indicate a relationship
between these two species, for they are separated
by many other characters.

Clayelina cylindrica (Quoy and Gaimard, 1834)
(Fig. 10. Plate 2e,f)

Polyclinum cylindricum Quoy and Gaimard, 1834, p.
Als.

Chondrastachys sp. MacDonald. 1458, p, 401,

Chondrostachys. macdonald? Bronn, 1862, Tal. 16 figs
1-7. Hartmeyer 1909, p. 1427,

Chondrostachys (evlindrica): Caullery, 1908, p, 229;
1909, p52.

Chondrastachys. eylindricva: Hartmeyer 1909, p, 1427,

THE AUSTRALIAN ASCIDIACEA 2 43

Fic. 10, Clavelina evlindrica: a,b, zooids from left and right respectively showing test constriction where zooid
attaches to common stalk (WAM 581.2.1, QM GH4068); ¢. zooid showing brood pouch with embryos (AM
Y1190): d, larva (SAM E1962). Scales: a-c, Imm; d, 0.2mm,

4d MEMOIRS OF THE QUEENSLAND MUSEUM

Claveling cylindrica, Michaelsen, 1930, p 475,

Poitoclivella eplindriva: Kott. 19S7a. p. Bl W987 2a. pe
5 (part, specimens from West {, Wright 1) 1876, p.
56 (part, specimen from Western Port). Millar, 1960,
p. 64; 1963, p. 716: 19660, p. 364, Not Kort 1972b,
Plo?s 975 pl (<= CL meluecensis).

Podoclavellaausiralis, Rott, 1957a, p 949 (part, specimen
from Port Denison).

Dis rr hie tien

New Recokos: Western Australia (Shark Bay, WAM
761,83; Wookoora Station, WAM 823,83, Foutmun’s
Abralhos, WAM 762.83 193.87 [94.88 223.88: off
Dongara, WAM 763,83, Cockburn Sound, WAM
581,2.31 73.75 81.75 124.75 156,75 165,75 17X75 75k-
60.83 7604.83 984.83, OM G9482: Shoalwater Bay. WAM
115.75; Mandurah WAM 85,75 867.86; Margaret River,
860.86; Albany. WAM 28.75). South Australia (Great
Australian Bight, SAM E1985, QM GI1l279 GH4151;
Yorke Peninsula, SAM E196@1: Speneer Gulf, QM
GH4287-8 GH4396). Victoria (Walerloo Bay, QM
GH1279; Portsea, QM GH40068) Bass, Strait, MV
£53291; Wilsan’s Promontory, MV F53362-5. Malla-
coota Inlet, MV F53660; Balnarring Beach MY P53658),
Tasmania (Bruny 0, MV £53659 SAM E1962) southern
Tusmania, TM D1922).

Peeviousty Reeornria Western Australia (Cock-
Surn Sound Michaclsen 1930, Millar 19634, AM
VIIST YLIYO Kotte t957a; Albany Millar 1963a).
South Australia (St Vincent Gull SAM L196 Kott
§972a). Victoria (Bass Strait’ — MacDonald 1858; Part
Phillip Bay — Millar 19634, 1966u; Western Port Bay:

Quoy and Gaimard 1634. Millar 1960, Kett 1974),
Queensland (Rowen — AM YING Kott 1957a),

The species is ollen liken in storm debris washed up
on beaches. The record [rom Queensland is anomalous,
extending the runge of this otherwise temperate species
intu the tropies, Mois possible that the specimen was
floating free in the East Australian current. The greatest
depth from which the species has been recorded is 7m
in Bass ‘Strait.

Derscriv rion

EXTERNAL APPEARANCE: The rope-like colonies
of this species are distinctive, consisting of a long
central stem (up to 600m or more long and 2 to
dem in diameter) with separate zooids crowded
along its length. Occasionally colonies are found
in which the central stalk is attached along part
of its length (QM GH4068); and sometimes it is
branched at the hase ty form holdtfasts. Zooids
are short (seldom more than 1.0 to 2,0em long)
and entirely free, separated tron the central stem
by a marked constriction through which the
vascular stolon of each zooid passes. The calony
is sometimes attached to the substrate (weed or
rock) by the basal (thickest) part ol the stalk. In
life, the colony is opaque blue or blue-grey,
Pigment patches in the median line, between the
siphans and over the anterior end of the endostyle
and the unus, sometimes persist in preserved

material, In preservative the zooids are often blue
and the Lest is always translucent.

INreERNAL Structure. The thorax is Jonger
than the abdomen, However, since muscles are
confined Lo the thorax it is often contracted in
the preserved material, and thorax and abdomen
are about equal length. Vhe thoracic masele
formula is LOB1OB 4D. Although the endostylar
muscles do not éxtend onto the abdomen, they
do extend to the end of the thorax rather than
the dorsal surface. They are oblique rather than
transverse, Consequently their contraction both
shortens the thorax and tends to draw down the
ventral surlace relative to the utrial siphon. Both
siphons are rather wide with circular museles
around them and are offen Maring and trumpet
shaped.

About 24 sickle shaped branchial tentacles are
present, Che transverse vessels expand into
relatively short and pointed dorsal languets over
the dorsal sinus. There are trom 9 to 13 rows of
50 to 60 stigmata. A small, rounded prestomach
lies about halfway down the relatively short
oesophagus. | he ytomuch ts a short oval halfway
down the abdomen and there is also a large oval
posterior stomach in the descending limb of the
gut loop. The rectum extends almost from the
pole of the gut loop at the posterior end of the
abdomen to the base of the atrial siphon, The
inal border is smooth.

Gonads are present in the gut loop, (te small
pear-shaped male follicles spilling over around the
outside of the Joop on the lettside of the abdomen,
A large brood pouch, formed by the expansion
of the oviduet al the postero-dersal end of the
left side of the thorax, contains developing
embryos, seldom more than 10. all at very different
stages of development. Some hive larval organs
fully developed and others about hall the size are
without obvious development of organs. It is
probable that fertilisation occurs in the brood
pouch,

Embryos are present in the broud pouch in
April, November and January from Shark Bay
and Cockburn Sound (WAM 73,75 758.83 761.83
764.83 984.83): in September trom Albany (WAM
28.75); in Octoher fram Western Port Bay (NMV
F53658), and in November from southern
Tasmania (1M 11922), However, they are not
always present al these Limes trom these locations.
Only few specimens have been taken from May
to August and these have oo larvae. From present
data, the species appears to breed from spring
through to the following autumn.

Larvae are large and almost spherical, the trunk
ahout 1.2mm diameter. They have 3 adheyive

THE AUSTRALIAN ASCIDIACEA 2 45

organs, triradially arranged and arising from a
flat frontal plate that is not expanded into lobes.
The adhesive organs consist of a shallow cup of
differentiated epidermal cells around a broad.
shallow axial cone, In the early embryo, the tail
is wound vertically around the median line of the
larval trunk with two adhesive organs and the
cerebral vesicle just to its left, and the third
adhesive organ to the right. As the larva develops
the tail passes horizontally across the anterior end
of the larval trunk from left to right, the two
adhesive organs on the left moving up to the tap
and the one on the left moving to the ventral part
of the anterior end of the trunk. The tail is long,
almost completely encircling the trunk. The
perforation in the Jarval test over each axial cone
is conspicuous in this species.

Remarks: Kott (1957a) and Millar (1960, 1963a
and 1966a) have suggested that this species and
C. australis are conspecific. In fact, although both
have zooids with large, robust thoraces and
pigment patches in the median line. there are many
distinguishing features.

Clavelina cylindrica invariably has short zooids,
with an especially short abdomen arranged around
a central common stalk; the zooids are always
entirely free of the common test. from which they
are separated by a sharp constriction; they have
a prestomach in a relatively short oesophageal
region; their thoracic muscles do not extend onto
the abdomen; and they have an almost spherical
larva and a rounded brood pouch. Clavelina
australis has long zooids with a long oesophageal
neck and no prestomach. Zooids arise from a basal
mat or stalk from which they are never separated
by a constriction and in which they are sometimes
partially embedded. Their thoracic muscles extend
the whole length of the thorax. Their larva is long,
and their brood pouch is elongate, lying across
the posterior end of the thorax.

Kott (1972a) confused C. evlindrica with C.
moluccensis, a8 neither have abdominal muscles
and both have a prestomach and rounded broad
pouch. Again the constriction at the base of each
separate zooid where it joins the central stalk
distinguishes C. cylindrica, as does the pattern of
its median pigment patches, the course of its
thoracic muscles and its smaller larvae,

Clavelina dagysa (Kott, 1957)
(Fig. 11. Plate 3a)
Podoclavella dagysa Kott. 1957a. p..93.
Dis rRUB Vion

New Recorps. Western Australia (Geographe Bay,
WAM 4.75 121.75, OM G9485)

Previousiy Recokbrp; Western Australia (Rottnest
I,— syntypes AM Y1I88, AM YII89 Y1191 Rott 1957a).

The species appears indigenous to the Western
Australian coast — from Cape Naturaliste to Rottnest
{. The maximum recorded depth is 20m,

Desc RIPTION

Exrernar Arrearance: The species is rela-
tively large (up to 4¢m long) with a wide (up to
lcm) thorax and a slightly narrower cylindrical

Fie. V1. Clavelina dagysa: a, colony (WAM 121,75): b.
solitary individual (syntype AM YI189); ed. larvae
showing adhesive organ from above. and from the
left Side (syntype AM YII88). Scales: asb, 2mm: c,d.
0.2mm.

46 MEMOIRS OF THE QUEENSLAND MUSFUM

stalk. rounded basally where it ix tixed in sane
and rubble. One specimen has been taken (AM
Y1191) in which two zooids are joined basally,
the posterior expanded portions of their abdomina
being embedded in common test. The test over
the thorax is always soft and glassy. while that
of the abdominal stalk is Jirm, with sand and shell
particles attached posteriorly, The zaoid extends
down inte the base of the stalk and the vascular
appendages are short. The apertures, on short
sipbons, are large, and flared when they are
expanded, The branchial aperture is turned
postero-ventrally and the atrial turned postero-
dorsally. In life the zooid is uniformly blue and
this colour remains in preservative.

INTERNAL Stevcrurr Zoows are long. the
thorax wide and roomy, joined by a narrow
oesophageal neck of variable length to the
posterior expanded part of the abdomen contajn-
ing the stomach, gut loop, gonads and heart. The
thorax is from half to one-third of the total length
ol the zooid, The thoracic muscle formula is
+20E,35,3D. The muscles extend along the whole
length of the abdomen.

There are & robust branchial tentacles alternat-
ing with $ smaller ones in a circle just anterior
w the larger ones, These all alternate with
rudimentary tentacles attached to whe underside
of a branchial velum projecting slightly into the
base of the branchial siphon. The duet of the neural
gland protrudes into the pharynx and has a curved
or straight vertical opening, The dorsal languets
are large triangular expansions of the transverse
membranes over the dorsal sinus, Stigmata are
in 24 to 30 rows of about 100.

The long oesophayus extends without interrup-
tion to the stomach in the posterior end of the
abdomen. There is no prestomach, The stomach
itself is oval, with a suture line, but although the
stomach collapses into folds there is no sign of
any structural folds or ridges. The rectum extends
the whole length of the long abdomen and projects
a short way up the thorax, the anus opening into
the atrial cavity in the vicinity of the fourth last
row of stigmata. Uhe anal border has about 20
lobes, The gonads are, as usual, in the gut loop.
They consist of pear-shaped male follicles
surrounding the ovary and spreading over the lett
side of the wut loop. There is no brood pauch
and embryos develop in the peribranehial cavity.
They are present in colonies collected in
November

Larvae are large, the trunk being [3mm long
with the tail wound three-quarters of the distance
aruund it. They have an ocellus and an otolith,
‘The frontal plate, supported as usual by a stolon

from the abdominal part of the incipient adult,
is Nattened. However, the usual clavelinid adhesive
organs dre not present, Instead, cach side of the
frontal plate is extended into an are of dilferen-
tiated epidermal cells that may have an adhesive
function, These two ares enclose the slightly
convex central part of the frontal plate.

Remarks: A colony ol C. dagysa consisting of
2 vovids. their abdominga embedded in a common
stalk is recorded above. This provides evidence
that this species, and probably C. estreariunt.
replicate from terminal ampuillae of the vaseulat
stolon as in all clavelinids. As in C. miiniata
Watanabe und Tokivka. 1973, from Japan,
replicated zooids probably separate [rom one
another to become solitary.

Clavelina dagysa shares many of its. principal
characteristics with the southern Australian C
ustrearium. Both species have wide, roomy
thoraces with oblique muscle bands dominating
the musculature; long zonids with long oesopha-
veal necks, and the posterior end of the abdomen
expanding in the base ol the stalk; short vasculac
stolons; sooids of the same uniform blue colour:
and the thoracic test glassy and bulloon-like.
sharply differentiated from the test of the stalk.
Both species have the posterior end of the stalk
expanded, but in C. dagysa it is not hard and
leathery and does not form a conical holdfast as
it does in C, asrrearium, ‘The species are
convincingly separated by their larvae, which in
C. dazyvsa do not have the usual clavelinid adhesive
organs while in C. osrrearium they do, Vhe range
ol these two indigenous species does not overlap
— C. dagvsa not being recorded suuth of
Geographe Bay and C. astrearivm not being
recorded west of Albany, However, they do not
appear to be sister species. Another large and
apparently solitary species. Clavelina brayiliensis
(Millar, 1977) from the Brazilian Shell, has the
same modified frontal larval plate as C. dag psd.
suggesting that it may be a plestomorphic
character inherited from some common ancestor
rather than being associated with the isolation and
speciation of the latter species in Australian
waters,

The other large. solitary species commonly
found in Australian waters, Clavelina meridiana-
lis, is tropical and is not recorded south of
Houtman’s Abrolhos on the Western Australian
coast, It is distinguished from both C. daerya and
C, asirearium by ils long thorax, more numerous
thoracic musele bands, relatively short zoids,
long vascular stolon, and the absence of the blue
Pigmentation so characteristic of the present
ypecies and its South Australian relative.

THE AUSTRALIAN ASCIDIACEA 2 47

Clayelina fecunda (Sluiter. 1904)
(Fig. 12)
Podoclayella fecunda Sluiter, 1904, p. 7.
Clavelina fecunda: Tokioka, 1967a, p. 101. Monniot,
1988, p. 203.

DISTRIBUTION:

New Recorps; Western Australia (Rottnest |.).
Queensland (Heron lL, QM GH4075 77 GH4086; Lizard
L., GH4110-1 GH4114-7). Philippines (QM GH405-6
GH474), Northern Terntory (Stephen’s Rock, QM
GH4697),

Previousty Reecornrp: New Caledonia (Monniot
1988). Indonesia (Sluiter 1904), Palau Is (Tokioka
196@7a),

The species appears 10 be a tropical western Pacific
one, recorded from shallow intertidal waters down to
20m in coral reef habitats.

DESCRIPTION

ExrernAr Appearance: Despite their small
size (about Icm long) the zooids are conspicuous
amongst the cryptofauna because of their bright
colour, having yellow patches each side of the

Fic, (2, Clavelina fectinda: a,b, colony (QM GH4077 and from Rottnest 1.); ed, zooids showmg numerous eggs
and incubating embryos in distal part of oviduct (QM GH4075); e, zooid (Rottnest 1.): f, larva (QM GH4075).
Scales: ajb, 2mm, e-e, 1mm; f, 0.1mm.

4B MLMOIRS OF THE QUEENSLAND MUSEUM

thorax, blue wi large patches over the endostyle,
between the siphons and spreading around the
atrial siphon and oyer the dorsal lamina, and two
lighter blue patches on each side of the thorax,
Jn preservative the zooids become uniformly dark
blue

One solitary zooid was taken, but tty basal test
was crowded With masses of terminal ampullae.
A colony consists of up to 10 crowded 7ooids
arising from a basal mass of common Lestio which
the abdomina of the vooids are partially
embedded. he thoracie test is clear and glassy
while the lower stalk-like section of the free part
ol gach gouid, and the basal test are firm and
translucent, Zooids are up to lem long and the
expanded thoraces up to 0.5em wide.

INTERNAL Sraeucrire: Phe thorax ts about one
third of the length of the zooid, with its branchial
aperture turned ventrally ang the atrial aperture
directed upwards. The thoracic musele lormula
is 7E,5B,3D, und all the muscles extend to the
posterior end of the abdomen. Sometimes the
ventral oblique muscles are obscure, There are 6
large branchial tentacles alternating with smaller
ones, The opening of the neural gland is a vertical
slit

There are 16 to 20 rows of about SO stigmata.
The oesophageal section of the ovoid is moderately
long, There is no prestomuch. The stomach, in
the posterior end of the abdomen, is quadrilateral
in section. and curves around against the mesial
wall of the intestine, It has a line ridge enclosing,
with the Suture linc, a pear shaped grea on its
outer wall. A rounded posterior stomach lies
almost in the pole of the gut loop. The proximal
part of the rectum is voluminous and yellow. The
ymooth, bilabiate anal opening is at the posterior
end of the thorax,

In mature specimens the gonads, in the loap
of the gul, are conspicuous, the testis follicles
spilling out over the left side of the gut loop, Large

égys are numerous and fill the whole length of

the oviduct, apparently beginning their develop-
ment in the terminal, expanded part of the oviduct,
which forms a brood pouch — although this does
not markedly protrude outside the wall of the
thorax.

Embryos and larvae are present in the newly
recorded specimens from Heron I. collected in late
October and carly November. They are also
present in some of the specimens from Lizard I.
which were all collected in Jine. They are not
present in specimen lot QM GH4117 also collected
in June Despite the large eggs, larvae are relatively
small, the trunk being 0.75mm long with the tail
would about half way around it, Three adhesive

organs lie on a flat frontal plate, each with a cup
of epidermal cells around a central cone, The
frontal plate is produced into small lobes between
the adhesive organs,

Remarks: Tokioka (1967a) remarked on the
unusually fecund appearance of this species, and
those newly recorded specimens that have
embryos, are no exception. Other distinctive
characters wre the short, stumpy zooids, and the
bright yellow colour in the living specimens.
Philippine specimens (QM GH474) are the same
colour as those recorded from Australia, described
by the collector (M.E. Cowan) as ‘transparent blue
with vellow markings’. Colonies and zooids of the
present species resemble those of Clavelina elegans
(Oka, 1934) from Japan, and conspicuous
morphological differences in the preserved
material of C. elegans and C. Jecunda have not
been detected, In ©, elegans, larvae have a longer
(0-9mm) trunk, and larger zooids (2 to 3cm) than
those of the present species, and yellow patches
wave nol present in living specimens. Clavelina
obesa has small stumpy zocids without yellow
patches, joined by stolons rather than heing
partially embedded in common test as in the
present species. and with transverse rather than
longitudinal musculature.

Clavelina meridignalis (Herdman, 1891)
(Fig, 13. Plate Ab-d)

Podoclavella meridionalis Werdman 1891. p. 603, 1899,
p4, Hartmeyer, 1919. p, 104, Hastings, (931, p. &t.
Kolt, 19574, p. 91; 1972d, p. 241. Not Sluiter, 1895,
p 165 (< Co rehtsta tsp.) Pizan, 1908, p, 197 (<
€. rubusta vse. Kott, 1972b, p. 167 (< ©
OSPOAPIUM), :

Podoclavella procera Sluvter, 1904, p, 8,

Clavelina enormis: Katt, 19574, p. 85.

Dis eration

New Recorps; Western Australian (Dampier
Archipelago, WAM 26.75; Monte Bello Is, WAM 749
$0.83; Houtman’s Abrolhos, WAM 747-8,83). New
South Wales (Port Stephens, QM GI0149, AM Y1999:;
Solitary ty, QM G9A41). Queensland (Bowen, QM
GH705 GH4080; Mackay, QM G4944 G9978),

Prrviousey Reeonwotp. Western Australia (Port
Charles — AM ¥1159 ¥1255 Kott 1957a; Cape Boileau,
Cape Jaubert Hartmeyer 1919). New South Wales
(Port Stephens AM (13936 Herdman 1899; Port
Hacking AM YXIS Kott 1972d, Port Jackson
holotype AM U11a, AM G12247 Herdman 1499),
Queenslund (Mackay — AM Y1192 Kolt 19573, Low
Is — Hastings 1931). Indonesia (Sluiter 1904),

The species is tropical. although is range on the
eastern Australian coast extends into the subtropical
waters of New South Wales. It has been taken at depths
down to 20m.

THE AUSTRALIAN ASCIDIACEA 2 49

DESCRIPTION

ExTERNAL APPEARANCE: The species is large
and solitary, up to 20cm long, consisting of a
cylindrical thoracic section in translucent (but not
glassy) test that is a half to one-third of the total
length and is from 0.5 to lem wide when expanded.
The stalk narrows from the posterior end of the
thorax to its base, where it sometimes breaks into
fine hair-like roots or occasionally branches off
the stalk of another zooid (see AM Y1255), but
most often is fixed directly to the substrate. As
it narrows, the stalk becomes increasingly hard
and leathery. In its upper part it contains the
abdomen of the zooid but toward the base it
contains the long vascular stolon. The large
terminal branchial siphon is turned over with its
opening directed toward the base of the zooid.
The atrial siphon is directed upwards. Both
siphons flare when they are expanded. In life the
thorax is a transparent green with a yellow patch
each side of the intersiphonal region and along
the endostyle. Some photographs of this species
show the test pink. In preservative the anterior
part of the thorax, brood pouch and abdomen
are dark blue to black, but the remainder of the
thorax is cream to brownish cream.

INTERNAL Structure: The zooid is robust but
not very long. Thorax and abdomen together are
about 3cm long in contracted specimens and even
in living zooids are only about half the total length,
the long vascular stolon occupying most of the
stalk. The muscle formula is 25-30E,2B,2D. Dorsal
branchial siphon muscles and the anterior two-
thirds of the endostylar muscles extend more or
less horizontally across the body to the dorsal
surface where they turn posteriorly and extend
as fine bands down onto the abdomen. There they
are joined by the posterior endostylar muscles
which are truly oblique, extending from the
endostyle to the postero-dorsal corner of the
thorax and onto the abdomen in a dorsal and
ventral band. Branchial tentacles are arranged in
4 rows, the largest in the posterior row. The neural
gland opening is a vertical slit between two fleshy,
protuberant lips. Dorsal languets are long, pointed
projections from the triangular expansion of the
transverse vessels over the dorsal sinus. There are
about 35 rows of 70 to 100 stigmata.

The oesophagus is moderately long, without a
prestomach. The stomach (in the posterior end
of the abdomen) has 3 longitudinal ridges as well
as the suture line in its inner lining. Folds in the
stomach wall of some specimens are, apparently,
artefacts of preservation. The stomach is often
stretched into a long, narrow oval, but in other
specimens it is more expanded. The gut is often

Fic. 13, Clavelina meridionalis: a,b, whole zooids (AM
Y 1255. QM G9641); c,d, thoraces removed from test,
showing muscles, embryos brooding (AM Y1255,QM
GH705); e, larva (AM Y1255). Scales: a,b, 5mm; ¢e,d,
2mm; e, 0.2mm.

voluminous and filled with mud. The anal opening
is about one-third of the distance from the
posterior end of the thorax, and its border has
about 10 rounded lobes. Gonads are present in
the gut loop, spilling out over the left side of the
intestine and the proximal part of the rectum. A
brood pouch forms from the expansion of the
distal end of the oviduct, which extends across
the posterior end of the right side of the thorax.
Developing embryos are present in specimens from
northwestern Australia collected in September
(AM Y1255) and in specimens from Bowen
collected in March (QM GH705).

The larval trunk is 1.1mm long and the tail is
wound only half way around the trunk. There is
the usual frontal plate expanded into small lobes
that alternate with the 3 adhesive organs triradially
arranged.

50 MEMOIRS OF THE QUEENSLAND MUSEUM

The species is known to regenerate new zooids
from old stalks (A. Birtles pers. comm.). The
presence of a single zooid arising from the stalk
of another suggests that occasionally replicates do
develop before resorption of the adult zooid.

Remarks: Being solitary and of large size this
species resembles Clavelina dagysa and the related
species C. ostrearium from southern Australia.
Like the latter species, C. meridionalis is known
to regenerate new thoraces from persisting stalks;
and like C. dagysa, it probably replicates zooids
from the terminal ampullae of the vascular stolon.
It is not known if zooids thus formed subsequently
separate from the parent, as in C. miniata
Watanabe and Tokioka, 1973. Clavelina meridi-
onalis is isolated from both C. dagysa and C.
ostrearium by its tropical range. The species is
further distinguished by its larger number of
transverse (endostylar) muscle bands, its long
vascular stolon that occupies an appreciable part
of the length of the stalk, its colour, and its smaller
larvae. The brood pouch, extending across the
posterior end of the thorax, resembles that of C.
australis rather than that of C. moluccensis and
C. cylindrica.

Kott (1972b), overlooking other differences,
misidentified specimens of C. ostrearium as C.
meridionalis on the basis of its solitary condition.

Podoclavella procera Sluiter, 1904 resembles the
present species in all respects, Sluiter even having
recorded the fact that the musculature on the
thorax was largely transverse.

Clavelina mirabilis Kott, 1972
(Fig. 14)
Clavelina mirabilis Kott, 1972b, p.165.

DisTRIBUTION

New Recorops: None.

Previousty RecorpDED: South Australia (Walde-
grave |. — holotype SAM E902, paratype SAM E903
Kott 1972b).

The species is taken at 23m in gravelly sand. So far
it is known from only a single location in the Great
Australian Bight.

DESCRIPTION

ExTERNAL APPEARANCE: Colonies consist of a
wide, wrinkled cylindrical trunk rising vertically
from a spherical sand-covered base (2 to 5cm in
diameter) that is probably buried in the substrate.
The trunk divides into branches each supporting
a group of long zooids, their thoraces projecting
separately from one another. The test is soft
throughout, the spherical basal portion being
protected by its brittle sandy outer layer.

Living specimens are buff or yellow-brown but
in preservative the firm test of the stalk is reddish-

Fic. 14, Clavelina mirabilis (paratype SAM E903): a, colony; b, thorax, removed from test; ¢, antero-dorsal
part of thorax showing muscle bands. Scales: a, lem; b, !mm; ¢, 0.5mm.

THE AUSTRALIAN ASCIDIACEA 2 S|

purple, while the projecting thoraces are more or
less Lransparent.

Internat Struetiete: Zgoids are long, op to
4om, Each consists of a relatively short thorax
and a long oesophageal neck that extends through
the trunk of the colony ind down into the spherical
base Where the rounded posterior part of the
abdomen, the postenor vascular stolon and the
terminal ampullac, are located. The musculature
consists of oblique and Jongitudinal bunds. with
the formula 7E.8B.1D. The muscles extend along
the length of the abdomen. An unusual transverse
muscle originates as a branch from the sixth
branchial muscle band about halfway down the
thorax. It extends dorsally beneath other longi-
tudinal muscles, with which it exchanges some
fibres. At the base of the atrial siphon it breaks
into narrow branches that join circular muscles
uf the atrial siphon. Branchial tentacles are in 3
rows, and the neural gland opening ts simple and
eweular. There are 15 rows of about 45 stigmata
per row. There is a long oesophageal neck, and
the stomach, at the anterior end of a posterior
expansion of the abdomen. is quadrilateral in
section, Gonads of the usual type are in the loop
of the gut posterior to the stomach. The larva
of Uns species is not known.

Remarks ‘The species resembles the new
tropical species Clavelina robusta in its large,
partially embedded zooids and in its musculature.
However, C. rubusta has an irregular branching
basal stalk, or a massive basal test from which
the zooids rise directly rather than extending
through a branching vertical trunk that intervenes
between the basal test muss and the zooid-bearing
head. Colomes sometimes have a superficial
resemblance to C. pyewdobaucinensis which often
has a similar massive basal text mass, Zooids of
the latter species, however, are completely
embedded, and the tharaces arc not free as in the
present species. The remarkable transverse muscle
that crosses beneath the other longitudinal muscles
from the centre of each side al the thorax to the
base of the atrial siphon is reminiscent af ©,
coerulew Oka (see Nishikawa and Tokioka 1976)
in which a muscle extends from the atrial siphon
to cross the predominantly transverse thorax
muscles. However, the course of this unusual
muscle in C. coerulea is outside the transverse
muscles, while in the present species the anom-
olous muscle runs inside the other predominantly
longitudinal ones, The transverse muscle in the
present species clearly onginates as a branch from
u longitudinal muscle and its formation could be
through the mobilisation of fibres from the
successive longitudinal muscle bunds it crosses.

Clavelina moluccensis (Sluiter, 1904)
(Fig. 1S. Plate 3e-h)

Claveline (Podiclavella) meridivnatis, Sluts. 1895. pe
164,

Podoclavella moluccensis Sluiter, 1904, 6. 5, Katt 195 7a.
p. 90; 1972a, p. 5; 1972b. p. lo7. Net Van Narne.
1918, py 130; Hastings, 1931, p. 82: Tokioka [967a,
p. 10S; Millar 1975, p. 211, Tokioka apd: Nishikawa,
1976, p. 347 (all. C. reAceste msp.)

Poduclavella evlindricas Kou, W72a, py, 3 (part,
specimens trom Hallet Cove): 1972b, p, 167, 1975,
p, 1) (976, p, 456 (part, specimens trom Mullucoota
Inlet),

The species name often is misspelt and even Stulter
(1904) used two different spellings. Che name derives
from the Moluccas. the Indonesian island group tral
is ils ype location

Dismrein. non

New Kecorps Western Australia (Exmouth Gull,
QM G9487; Houtman'’s Abrolhos, WAM 374.80; Shark
Bay, WAM 757.83: off Dongara, WAM 756.483;
Cockburn Sound, WAM 37,72 31,75 76.75 112,75
151,75, QM G9671; Bunbury, WAM 19.75; Albany,
WAM 752.83 $54.83). South Australia (Great Australian
Bight, OM GH976, SAM E1988 9; Pleuricu Peninsula,
SAM E(964, Nuyts Archipelago, SAM E1965. Yorke
Peninsula, SAM E1966. St Vincent Ciull, SAM El967
8, QM G9S1S GH4066-7 GII4069 FI, BM 1951.9, 10.8;
Kangaroo |, QM 11996). Victoria (Bass Strait, MV
H376). Queensland (Heron |, QM G9517 GIOOSI
GL1913 GH359 GH4088; Lizard 1, QM G9790: Martha
Ridgeway Reel, OM Git246 GH543), Philippines (QM
G12754 GH4io GH4d2? 3 GIISSS), Singapore, ZMC
227.07.

Permionsiy Recorpen Western Australia (Cape
Boilewu = Stuiter 1885; Coekburn Sound = AM ¥120
Kott (9574; Hamelin Bay AM Y1II97 Kore 1957u.
Albany AM ¥1199 ¥ (203) South Australia (Creat
Australian Bight SAM E1963 Kott 1972b, SAM
P2086 Kott 1975, Spencer Gull AM YII9R Kot
10574 SAM BI969 72 Kort 1972u, 1975; St Vingent
Gull SAM E997 Kol [972a), Victoria (Maltacootu
Inlet — Kott 1976). Indonesia (Slutter 1904).

Although there are no records from New South Wales.
the species has been photographed {here, at Jervis Bay
and Port Stephens (photos P. Frederickson). ‘This
apparently isa tropical western Pacific species. Itoceurs
quite commonly in the Philippines (see new reeards),
It is seasonal in some locations (ee Tipari Reel:
Shepherd fide Kor (972a), dying off at the beginning
of summer and reappearing in carly winter, Apparently
this is not always the case for there are records fron
Cockburn Sound for every month except May and
records from the tropics include the winter months

DescRIPTION

ExTeRNAL AprearRAnet: Large irregular col-
onies with single zouids or upnght stalks support
groups of zooids separated [rom one another to
various degrees, from whole zooids to at least the
thoraces separated. The test of the basal stolons

52 MEMOIRS OF THE QUEENSLAND MUSEUM

hic 15, Clavelina moluccensis: ajb, colonies (SAM E2086: WAM 854.83); « sooid (QM GH 4070): d. thorax
(WAM 854.83): e, larva (AM YI196). Scales: aye,d, 2mm; b, lem; e. 0.2mm).

ortest mass and the lower part of the zooid-bearing
lobes is firm and only slightly translucent, and
the test over the thoraces is solter and more
transparent, although it is not glassy. Sometimes
the basal test develops into a thick stalk-like
support for the colony and sometimes it forms
fleshy stolons. The free, branched, zooid-bearing
clumps or single zooids are from about 0.8 to
nearly 3cm long.

Living zooids are blue, some pale, others darker,
the colour conspicuous, showing through the
transparent test. A characteristic pattern of
patches of darker blue is always around the
anterior end of the zooid. This consists of a
transverse line of 3 blue spots between the siphons,
a patch over the anterior end of the endostyle,

another posterior to the base of the atrial siphon
and a small spot over the anus, These patches
of blue persist in preservative though zooids are
often bluish-black.

INTERNAL Structure: Zooids are from 0.5em
to 2.5em long, The thorax always longer than the
abdomen and, in preserved specimens in which
the muscles are contracted, it is no wider than
the abdomen. The vascular stolon is long, a great
part of it in the upright zooid-bearing stalks.
Terminal ampullae of the vascular stolon are
numerous. branching off along its whole length.

The apertures are on short siphons, the atrial
usually terminal, turned slightly ventrally, and the
branchial subterminal and curved ventrally and
posteriorly. Thoracic muscle bands are all

THE AUSTRALIAN ASCIDIACEA 2 53

transverse, extending across the sides of the body
to the dorsal border where they disappear, A few
fine bands sometimes can sometimes be detected
along the dorsal surface extending onto the
ubdamen, and, although these presumably are
present always, they are inconspicuous and
difficult to demonstrate in unstained material, The
muscle formula is 20-30E,3B,3D, Contraction of
the transverse thoracic muscles causes the tharax
in become Jong and narrow.

There are about 24 branchial tentacles of
Varying size. The neural gland opening is elliptical,
set vertically and slightly obliquely, From 14 to
22 rows of about 80 stigmata are in the branchial
sac,

The oesophagus eXtends down the anterior one-
third of the abdomen, interrupted about halfway
along its length by a small rounded prestomach,
The stomach is large and roomy. Generally its
internal lining is interrupted only by the suture
line, however, in a large specimen from St. Vincent
{rulf (OM GH4066) there are also 3 fine ridges.
A large posterior stomach occurs at the posterior
end of the descending limb of the gut loop before
it curves around and expands into the rectum,
which occupies the Whole of the ascending limb
of the Joop. The anal opening is about halfway
up the thorax. ils border smooth and bilahiate.

Gonads are of the usual form, located in the
gut loop posterior to the stomach, and the pear-
shaped male follicles spill out oyer the posterior
end of the gut loop obscuring it. Eggs are relatively
small. Developing embryos are present in a
rounded brood pouch formed by the expansion
of the distal end of the oviduct projecting from
the postero-dorsal corner of the thorax, They
continue their development in the peribranchial
cavity. Embryos are present in colonies fram
Rottnest (WA) and Yorke Peninsula (SA)
collected in October to December (WAM 11.275,
AM Y1196, SAM E1966); and irom Bass Strait
in December (NMV H376): in one colony from
the Fleurieu Peninsula (SA) taken in July (SAM
E1964), and in colonies from Heron [,(QM G9517)
in November. Young colonies were common at
Heron I. in May 1988.

The larval trunk is 1.2mm long and is almost
spherical. Adhesive organs are large, with the usual
cup of modified epidermal cells around the central
cone. They are supported by thick stalks arising
fram a broad frontal plate which is produced into
conspicuous lobes between the adhesive organs,
‘The tail winds completely around the trunk.

Remarks: Colonies of this species resemble
those of C. australis and C. robusta nap. and
some of the larger specimens also have zooids of

similar size. However. C. ntoluccensix can be
distinguished readily by its transverse muscula-
ture, absence of conspicuous thuscles on the
abdomen, line of 3 pigment patches between the
siphons (in addition to the median patches dorsal
and ventral to the atrial and branchial siphons
respectively) relatively short oesophageal neck,
prestomach, rounded brood pouch, and a large
larya with a long Jarval tail that completely
encircles it.

Clavelina cylindrica has a similar brood pouch
and prestomach but differs in its oblique and
longitudinal muscles, even shorter abdomen and
regular colony. C. nigra n.sp. has similat
Lransverse muscles and prestomach but lacks the
characteristic pigment patches. C. coerulaea Oka
also has similar transverse muscles but there are
also longitudinal muscles, zooids narrow toward
the base. und lack the prestomach.

Clavelinag muluecensis docs occur in the
Philippines, However the records of Van Name
(1918) and Millar (1975) from thst locution, as
well us those of Hastings (1931) from Low ts,
Tokioka (1967a) fram the Palau Js, and Tokioka
and Nishikawa (1976) from Japan. are not of this
species. Podoclavella moluecensiv, Van Name.
1918 jncludes numerous species (include one of
the genus E&ulerdmania). it is unlikely thal the
present species is included, however. for all his
specimens had predominantly longitudinal mus-
cles that continue onto the abdomen. Some of
Van Name's specimens probably are conspecific
with ©. molwevensis; Tokioka 1967a, Podoclavella
moluecensis: Millar, 1975 and C. molucecersis:
Tokioka and Nishikawa, 1976, which are all
assigned lo the new species, Clavelina robusta (see
below).

Sluiter’y (1895) description of this species
includes a record of its characteristically spherical
brood pouch (present even before it is filled with
embryos). and its transyerse muscles.

Clavelina nigra n.sp
(Fig. 16. Plate 4a)
Dis pepe tian
Tyrer LoeAriy: Western Austraha (Roitnest 1, Roe
Reef, 8m, coll, N, Coleman, AMPS, 6.3.72. holotype
QM G94k6),
Furrire Rreorns: Note.

Description

Colonies are irregular, consisting of thick basal
stolons fixed to the substrate along their length.
with upright branches containing single zooids or
groups branching from a common stalk, Usually
zooids are separate for most of their length
although this is variable and occasionally only the

54 MEMOIRS OF THE NUEENSLAND MUSEUM

Fic. 16, Clavelina nigra n.sp. (holotype QM G9486):
a, colony; b, zooid. Scales: a, 5mm; b, 1mm.

thoraces are separate. Separate zooids are up to
lcm long. The large subterminal branchial siphon
is turned ventrally and the narrow atrial siphon
is directed upwards, both flaring out from the
aperture. Living specimens are dark grey to black
with a white rim around each aperture. Even in
preservative the body wall is crowded with dark
particles.

INTERNAL StRucTURE: The largest zooids are
barely Icm long and the thorax is slightly shorter
than the abdomen. Thoracic muscle bands are
transverse, with the formula 30E,4B,2D. Muscle
bands are fine, forming an almost continuous coat
over the thorax, but they disappear along the
dorsal border and none were detected on the
abdomen. Contraction of the thoracic muscles
causes the thorax to elongate. Eight large
branchial tentacles alternate with 8 smaller ones
in a circle slightly anterior to them.

There are 19 rows each of about 50 stigmata.
The oesophagus is interrupted by a small round
prestomach about halfway along its length. A
narrow oesophageal neck occupies half the length
of the abdomen. The stomach is long, with a suture
line, but no other folds or ridges. A long posterior
stomach is present in the last quarter of the
descending limb of the gut loop. The rectum
extends the whole length of the abdomen and the
smooth-bordered anus opens about halfway up
the thorax. Gonads are present in the gut loop,
but are not mature in this holotype colony.

Remarks: The present species is strikingly
similar to C. moluccensis. Both have transverse
thoracic muscles, a prestomach, and similar, rather
irregular, colonies with zooids arising singly or
in clumps from common basal test or stolons. At
least the thoraces, and sometimes the whole
zooids, are separate from one another. Generally,
the zooids are not as robust as C. moluccensis,
the muscle bands are finer forming a continuous
coat over the thorax, and are especially numerous
for such small zooids. The abdomen is longer than
the thorax in the present species, while it is shorter
in C. moluccensis, and the numbers of stigmata
per row are about half of the number in C.
moluccensis. The most compelling difference
between the two species, however, is the colour.
The present species does not have the characteristic
pigment patches of C. moluccensis, it is not blue,
it has a white band around the apertures, and
dark pigment particles are crowded throughout
the preserved specimens.

The colour resembles that of C. cyclus Tokioka
and Nishikawa, 1975 (see Nishikawa and Tokioka
1976) from Okinawa I. and the Philippines (QM
GH475). However, the white band is around the

THE AUSTRALIAN ASCIDIACEA 2 55

base of the branchial siphon in C. cyc/us — not
around its rim as in the present species; and the
thoracic muscles of C. cyclus are not transverse.

As far as is known, the present species occurs
only at Rottnest I, It may be indigenous, with
a range confined to Cockburn Sound.

Clavelina oliva n.sp.
(Fig. 17, Plate 4b)
DistTRIBUTION

Tyer Locatiry: Western Australia (Shark Bay, Dirk
Hartog I., Ransonnet Rocks, Cymadocea bed, coll. L
Marsh 7.4.79, holotype WAM 983.83; Dampier
Archipelago, Kendrew I., 20°28730’S 116°32’E, outer
metre 8, coll. Western Australian Museum Crown of
Thorns Survey, paratypes WAM 217.75).

Furruer Recorps: Western Australia (Dampier
Archipelago, WAM 213.7 thorax missing 1051.83;
Houtman’s Abrolhos, WAM 231.88). Queensland
(Lindeman I., QM GH4085; Lizard 1, QM GH4108).
Northern Territory (Darwin, QM GH4211 GH 4800-
1). Philippines (QM G12753 GH476 GH490 GH558).

DESCRIPTION

EXTERNAL APPEARANCE: Specimens available
are usually solitary, upright, club-shaped zooids
on a narrow stalk which is divided into root-like
branches at its base. The species is common (with
Nephtheis fascicularis) in Darwin Harbour (at
13.5m) with its long stalk embedded in the silt
and only the thorax rising above the level of the
sea floor. Specimens have to be dug out of the
substrate. The base of the stalk has often been
severed. A colony with 4 zooids was collected from
Lizard I. (QM GH4108). Another specimen lot
(WAM 217.75) has 3 zooids that were possibly
joined by a basal stolon, which could have
remained attached to the substrate when the
specimens were collected. Collectors field notes
and photographs of the specimens from the
Philippines (M.E. Cowan) indicate that the species
occurs either in small colonies with few zooids
or as solitary individuals.

The separate zooids are from 2.5 to 5.0cm long
of which the thoracic, abdominal and posterior
abdominal sections are each approximately one
third. The abdominal section usually becomes
progressively narrower with progressively firmer
test toward the base, although sometimes the
diameter decreases very abruptly to the narrow
stalk at the posterior end of the abdomen, The
thorax is about 8mm in diameter, abdomen about
5mm and narrow vascular stolon a maximum of
only 2mm in diameter becoming narrower toward
the base.

The test on the stalk is usually quite hard,
leathery and opaque, although in all the specimens

from Queensland it is firm and translucent, and
sometimes is rather short. On the thorax the test
is soft, flexible, and transparent, but not glassy.

In preservative the thorax is either transparent
(specimens from Darwin), or dark blue, the colour
fading toward the dorsal surface of the thorax
and on the abdomen (specimens from Western
Australia). Collectors notes and photographs of
specimens from the Philippines indicate living
specimens were dark (black?) with white, or
yellow, or green bands around the siphons
sometimes extending down the dorsal surface of
the thorax and with speckles of the same colour
on other parts of the thorax. In preservative some
dark patches persist over the dorsal ganglion which
extend around the base of the branchial siphon.
However, in Darwin Harbour the populations of
this species have a generally colourless thorax. The
stalk and abdomen are yellow, and some yellow
pigment extends up along the endostyle and
around the apertures.

INTERNAL STRUCTURE: The thorax Is relatively
large and roomy. The siphons are large, the
branchial siphon curved ventrally and the atrial
directed upwards. In addition to the usual
endostylar, branchial and dorsal muscles, there
are also conspicuous muscles from the atrial
siphon extending down the dorsal surface. The
muscle formula is I0E,5B,2D,4A. Endostylar
muscles are spaced down the whole length of the
endostyle. In contracted specimens muscles are
seen to run transversely across the thorax,
extending down the dorsal border of the thorax,
onto the abdomen and along its length. In larger
specimens 6 large branchial tentacles lie at the
base of the branchial siphon, slightly anterior to
them a circle of 12 of moderate length, and
rudimentary tentacles are in the most anterior
circle, However, in the small specimens from
Lizard I. there is only a single circle of 9 rather
short branchial tentacles. The opening of the
neural gland is vertical, protruding slightly into
the pharynx.

Stigmata and stigmatal rows both increase with
body size, ranging from 11 to 22 rows of about
60 to 100 stigmata. When little contracted, the
oesophageal neck occupies about half of the
abdomen, the stomach being about half way down
the abdomen. There is no prestomach. The
stomach is large and wide, and sometimes has folds
in the preserved specimens, although these are
probably artefacts. The gut loop behind the
stomach is obscured by gonads. The smooth-
rimmed bilabiate anus opens at the posterior end
of the thorax. Embryos are present in the distal
part of the oviduct across the right side of the

56 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 17, Clavelina oliva n.sp.: a, colony (QM GH4108); b, solitary individuals (QM GH4108, WAM 1051.83);
¢, whole zooid in test (holotype WAM 983.83); d, zooid removed from test (QM GH4108); e, larva (QM
GH4085). Scales; a,b, 5mm; c, 2mm; d, 1mm; e, 0.2mm.

THE AUSTRALIAN ASCIDIACEA 2

posterior end of the thorax in specimens collected
in February from the Dampier Archipelago
(WAM 217.75), from Lindeman |. collected in
January(QM GH4085) and from Darwin collected
in August (QM GH421 1).

A mature larva present in the specimen from
Queensland (QM GH4085) has a trunk of 0.8mm
to 1.0mm, The tail is wound more than halfway
around the trunk. Although ovolith and ocellus
are present in the cerebral vesicle, these are not
in good condition and the pigment appears lost.
A rather narrow frontal plate has angular
ampullae at the base of each adhesive organ,

Remarks: The zooids of this species closely
resemble thase of Clavelina viola Tokioka and
Nishikawa, 1976 from Sagami Bay. Japan. The
holotype of the Japanese species ts a large colony
of 164 zooids, and this constitutes its major
distinction from the present species which never
forms large colonies. As indicated by the
oeeurrence of some small colonies in the Philip-
pines and the presence of enlarged terminal
ampullae in one specimen from Shark Bay (WAM
993.83). it does sometimes replicate zooids fron)
the basal stolon. However. replication seems not
prolific: or perhaps, as in C. mifniafa Watanabe
and Tokioka. 1973, replicates. separate from one
another,

The colour of the living zooids of Clavelina viola
is recorded by Tokioka and Nishikawa (1976. p,
345)

thorax ... faintly purplish but darker near the

posterior margin and in the siphonal area where

4& prominent deep purplish pigmentation ts

extending from the dorsal side of the atrial siphon

onto euch Jateral side to embrace an area coloured
yellow between both apertures.

Greater variation occurs in the colour pattern
of C. eliva, with generally more yellow, white or
green pigmentation in relation to the dark or
purple areas, The inverted E-shaped dark patch
over the dorsal ganghon that is considered a
characteristic of C. viola is not presentin C. alive.
Although longitudinal muscles from the atrial
siphon have not been described for C. viola. they
may haye been overlooked and their presence in
C. oliva does not necessarily constitute a difference
between the species.

The characteristics that the zooids of C. viola
share with the present species and that distinguish
both from other species are: length of the vooids
{3 to 4em); their general shape, progressively
narrowing trom the thorax to the thin basal part
of the stalk: lang vascular stolon; general
characteristics of the muscle formula. with a
preponderance al oblique muscles; a relatively

we
~)

short oesophageal neck and the long posterior
expanded section of the abdomen with its large
roomy stomach that collapses into folds in
preserved material.

Clavelina oliva is distinguished (rom the solitary
C. dagyvsa, an indigenous Western Australian
species not recorded north of Cockburn Sound,
by its size; its attenuating basal stalk (the stalk
of C. dagyse expands basally), its long narrow
yascular stolon (instead of the short vascular
appendages of C. dagysa in which the zooid
extends almost to the base of the stalk); and its
fewer muscles.

Clavelina ostrearium (Michaelsen, 1930)
(Fig. 18. Plate 4c)
Podaclavella ostrearium Michaelsen. 1930, p.467
Podoclavella meridtonalis: Kott, 1972b, p. 167,

DISTKIRL TION

New Recoros, Western Australia (Albany, WAM
26,87). South Australia (Nuyts Archipelago, SAM
£ 1973-4. OM GH2313; Pearson L, OM GH935; Great
Australian Bight, QM GH936 GH4222).

Previolsty Recorprp: Western Australia (Albany
— Michaelsen 1930), South Australia (Pearson 1,
SAM E1992 Kotr 1972b).

The species oceurs across the southern coast of
Australia. mainly in the Great Australian Bight but
extending into Oyster Harbour, Albany at its western
limits, IL has nol been recorded inside Spencer or St
Vincent Guifs. however, and its presently known oastern
limit ts at Pearson 1.

Drscrirtion

EXTERNAL APPEARANCE: The species is solitary,
Individuals are 6 to lem long, and consist of
a spherical to oval balloon-like thoracic portion
of glassy test enclosing a uniformly blue zooid-
supported on a long firm, gelatinous stalk, wide
in its Upper part, and usually becoming leathery
and tapering toward the base where it again
expands into a tough conical hold fast or club-
shaped, rounded base. The branchial aperture is
termina! and the atrial aperture subterminal. Both
apertures ure on flaring siphons. The zooid extends
right to the base of the stalk and the vascular
stolon is very short. The expanded base contains
the expanded posterior end of the abdomen.

INTERNAL STRUCTURE The most conspicuous
features of the zooid are the large (about 2om
long) roomy thorax and the long, thin oesophageal
neck. Muscle bands of the thorax are longitudinal
and oblique, with the formula 20E,10B,SD. They
extend along each side of the abdomen. At the
base ol the branchial siphon 20 fairly large stumpy
tentacles are in 3 concentric circles, with the larger
tentacles in the posterior circle. The small tentacles

58 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 18. Clavelina astreariwn: adh, solitary individuals
(QM GH2313, SAM E1973): ¢, thorax showing
muscles (SAM E1973): d. larva (QM GH936). Seales:
a,b, Smm; ¢, 2mm: d, 0.2mm.

in the anterior circle are on the underside of a
distinet velum that projects into the base of the
siphon. The duct of the neural gland projects
slightly into the pharynx and has a_ vertical
elliptical opening, sometimes curved into an arc.
There are 24 to 34 rows of at Jeast [00 stigmata
per row.

The Jong oesophagus extending through the
greater part of the stalk of the zooid. It is not
mterrupted by a prestomach. The anus, its border
divided into 20 rounded lobes, opens opposite the
fourth last row of stigmata. The gut loop encloses
the gonads. consisting of the usual central ovary
surrounded by pear-shaped male follicles that spill
over onto the side of the gut loop and obscure
the long oval stomach and gut loop. Embryos
develop in the distal part of the oviduct and in
the pertbranchial cavity but there is no protruding
brood pouch. Embryos are present in colonies
collected in March (QM GH936),

Lurvae are moderately large, the almost
spherical trunk being 1.25mm long, The frontal
plate is broad and supports the usual 3 large
triradially arranged. almost sessile adhesive
organs. The tail is long, winding the whole way
around the trunk, Shepherd (see Kott 1972b)
observed that new thoraces regenerate on old
persisting stalks. There is no evidence of vegetative
replication in the examined material.

Remarks; The species seems close to Clavelina
dagysa, both being uniformly blue in life, and
solitary with large, roomy thoraces, long oeso-
phageal necks, short vascular appendages, and a
similar muscle formula with predominantly
oblique muscles. The stalk of C. dagysa usually
is thicker and shorter, does not become as hard
and leathery, and does not expand into a conical
holdfast. However, the most compelling distine-
tion between the two species is seen in the larvae
— C. ostrearium has characteristic clavelinid
adhesive organs while C. dagvsa does not.

Michaelsen’s (1930) specimen from Oyster
Harbour. Albany, is described as 11cm long with
a thin, leathery stalk, sharply cut off from the
glassy thoracic portion which is about 2em long,
and has a short vascular stolon. Thus it conforms
with all the characteristics of the present species,

Kott (1972b) mistook specimens of this species
tor C. meridionalis, which is also a tall solitary
species with a leathery stalk, The latter species
however, has a longer, narrower thorax, a shorter
oesophageal neck, a long vascular stolon, and 1s
a different colour.

Clavelina pseudobatudinensis (Kolt, 1976)
(Pig. 19. Plate 4d-{)
Oxvearvnia pseudohaudinensis Kott. 1976, p. 54.
Clayelina baudinensiy Kott, 1957a, p, 87 (part. not
specimens from Rottnest with small larvae); 1972a,
p. & 1972b. p. 167. Millar. 1966a. p. 363.
? Srnelavella lesseni Caullery, 1900, p.1419.
7 Svnelavella australis: Caullery, 1900, p,1420,

DISTRIBUTION

New Recorps Western Austraha (Houtman’s
Abrolhos, WAM 370.80; Cockburn Sound, WAM
745.83). South Australia (Spencer Gull. QM GH4399
GH4401-2; St Vincent Gulf, QM GIO118: Kangaroo
1. QM G11992), Victoria (Port Phillip Bay, QM G9484
GH30). New South Wales (Jervis Bay, QM GI009I:
Wreck Bay, AM ¥2001). Lord Howe [., (QM GH4375),

Previovsry Recorpen, Western Australia (Rotinest

AM Y1112 paratypes C. buueinensis Kott, 1957a).
South Australia (Great Australian Bight — SAM E1977
Kott 1972b; St Vincent Gulf SAM E1975 E1976 Koll
1972a). Victoria (Port Phillip Bay Millar 1966a;
Western Port Bay — AM Y1I113 holotype. AM Y1122
paratypes Kott 1976).

THE AUSTRALIAN ASCIDIACEA 2 59

Fic. 19, Clavelina pseudobaudinensis: a, colony (SAM E1977); b. zooid (QM G11992); ¢, thorax (WAM 745,83);
d. various views of the stomach (QM GH4072); e, larva (holotype AM Y1113). Scales: a, 5mm; b,c, |mm;
d_ 0.25mm, e, 0.2mm.

60 MEMOIRS OF THE QUEENSLAND MUSEUM

The species has a wide range in temperate waters from
Houtman’s Abrolhos in Western Australia to Jervis Bay
in New South Wales.

DESCRIPTION

EXTERNAL APPEARANCE: Colonies are
mushroom-shaped, with a thick stalk and an
almost spherical expanded head. The test is glassy
and transparent on the upper surface where the
zooids open. The stalk is firm, but not leathery.
It is sometimes relatively long and narrow (up
to 3cm long but less than 0.5cm diameter) with
a head of 2cm diameter (AM Y1112 from Rottnest
and QM GI11992 from Kangaroo I.) However,
more often the stalk is short, wide, sometimes
bulbous and almost the same dimensions as the
head. Zooids are almost completely embedded in
the test, only their anterior ends projecting
separately from the upper surface. The living
specimens are transparent or grey with small white
spots on the test and two conspicious blue pigment
patches on the anterior end of each zooid — one
a transverse arc between the siphons and the other
a longitudinal patch over the anterior end of the
endostyle. In darker specimens a horseshoe-
shaped patch of white can be seen around the
cerebral ganglion. The transverse arc of blue
colour sometimes becomes either a large oval
patch or separates out into 3 separate patches in
the preserved specimens. There is also a small
transverse patch of blue over the anus.

Blood vessels extend parallel to one another up
toward the top of the stalk where they end blindly.
Although vegetative buds were not observed it is
possible that they develop here as they do in the
genus Nephtheis.

INTERNAL STRUCTURE: Even partially relaxed
zooids are not more than Icm long, the thorax,
the oesophageal neck and the posterior expanded
part of the abdomen each being about one third
of the total length.

Oblique and longitudinal muscle bands on the
thorax have the formula 6E,3B,0D,3A. Sometimes
muscle bands appear more numerous (up to
10E,6B,5A) when the thorax is not so strongly
contracted and the separate bundles of fibres in
each band separate from one another (see WAM
745.83, QM GH30). Branches from the adjacent
branchial and atrial muscles extend across the
inter-siphonal dorsal line. Muscles continue along
the ventral side of the abdomen, and in many of
the contracted zooids examined the abdomen is
drawn up into a thick trunk behind the thorax
(AM Y1112), or is folded up against the posterior
end of the thorax, completely obscuring the
oesophageal neck. Branchial tentacles are in 3

concentric circles, 6 large tentacles, at the base
of the siphon, 12 moderately sized ones slightly
anterior, and 12 small ones in front. The long,
narrow, vertical opening of the neural gland
projects into the pharynx.

There are 18 to 20 rows of 30 to 40 stigmata.
Dorsal languets taper to a long, narrow point.
The oesophagus is long and narrow in relaxed
zooids, and there is no prestomach. The relativley
short stomach is rectangular in outline, but apart
from the suture line it has no structural ridges.
Its mesial surface projects out at each side to
embrace the intestine which it lies against. A long
oval posterior stomach lies at the posterior end
of the descending limb of the gut loop. The anus,
bordered by rounded lobes, opens near the
posterior end of the atrial cavity.

Embryos begin their development in the distal
end of the oviduct, which forms a brood pouch,
curving around from the oesophageal neck across
the posterior end of the right side of the thorax.
They complete development in the atrial cavity
on the right side. Embryos are present in colonies
collected from Rottnest I. in November (AM
Y1112). In South Australian specimens collected
in September (QM GIOI18) there are embryos
developing in the brood pouch and atrial cavity,
although tailed larvae are not present. Embryos
and tailed larvae are present in the holotype
colonies and in the specimen from Lord Howe
1. (QM GH4375) collected in October. Specimens
collected in March, April, June from South
Australia and Victoria do not contain developing
embryos. Apparently there is a single breeding
season at the beginning of summer for this
temperate species.

Larvae are large, the larval trunk 0.9cm long,
with the tail wound five-sixths of the distance
around it. The three triradially arranged stalked
adhesive organs are supported on a frontal plate
with small lobes produced from it to alternate with
the adhesive organs. Each adhesive organ has a
cup of modified ectodermal cells around the
central axial cone. In one specimen (QM GH4375)
the rows of stigmata in the larvae are actively
subdividing and there are about 6 rather irregular
rows.

Remarks; Some colonies of this species (AM
Y1112, QM G11992) closely resemble those of
Clavelina baudinensis, having a fairly long and
relatively narrow stalk. However, more often the
stalk is short, wide and sometimes massive and
bulbous. The zooids constitute a reliable means
of distinguishing the species, for, while C.
baudinensis never has oblique muscles, C.
pseudobaudinensis has at least 5, extending from

THE AUSTRALIAN ASCIDIACEA 2 ot

the anterior half of the endostyle. Also, the
oesophageal neck of C. pseudobaudinensiy is
shorter, about the same length as the posterior
expanded part of the abdomen, while in C,
baudinensis it is two-thirds of the Jength of the
wbdomen. Living specimens can be distinguished
by the transverse arc of blue pigment between the
siphons. Further, C. pseudoebaueinensis has a
typically clavelinid larva. while the larvae of C.
faudinensis are small and thew adhesive apparatus
is unique — not being known forany other species.

Clavelina pseudobaudinensis has a wide range
in Australian temperate waters, while C. bawedi-
nensis is apparently confined to Cockburn Sound.

The two specimens referred to by Cwullery
(1900). on which he based the definition of the
genus Svaclavella, could be either the present
species or C, haudinensis, However, since neither
of the French expeditions which collected
specimens, the Cuguille and the Astrolabe
respectively, visited Western Australian waters,
Caullery's species are probably synonyms of C.
pseudobhaudinensis,

Possibly the species most closely resembling C.
pseudobaudinensis is C, qustraliy which, although
they are not embedded completely. has large
vooids, similar larvae, incubatory pouch and white
Spots im the test.

Clavelina robusta 11.3p.
(Fig, 20, Plate 4g)
Podaclavella meridionalis; Pizon, 1908, p. 197.
Podoclavella moluceensisy "Nan Name, 1918, p, 130
(part). Hastings, 1931, p. 82. 2Millar, 1975, p.2tl,
Clavelina maluccensis: Tokioka, 1967a, p. 14. Tokigkie
and Nishikawa, 1976, p. 347,

Dis rR IRL TION

Tyre Locarpry Western Australia (Houtman'’s
Abrolhos, Goss Passage, Beacon, Wallabi Group. 20
30m, coll. WA Museum party, 1.4.78, holotype WAM
753.83 OM GH2I40; paratype WAM 755,83),

FURTHER Reeornms: Western Australia (Broome,
WAM. 751.83. QM GH2139: Exmouth Gull. OM
G1193d; Shark Buy. WAM 754.83; Houlman’s Abrol-
hos, WAM 374,80 230.88). Queensland (Lizard 1. QM
(GH4073), Northern Terttory (Port Essington, QM
GH4074), Philippines (QM G]2757).

Pervionsiy Recorben Queensland (Low ly AM
(313503 Hastings 1931), Palau Is (Tokioka 1967a).
Indonesia (Pizon 1908). Philippines (7Van Name 19],
Millar 1975), Japan (lakioka and Nishikawa 1976).

The species has w tropical western Pacific range,

Deseriprion:

Externat Appearance: Colonies are large,
with large zooids, dark blue in preservative clearly
seen through the whitish translucent test_ In some

zoulds fram which the colour is fading the blue
pigment spreads round the sides from the dorsal
surface and extends in a band along each side
of the endogstyle. [t encloses a light coloured area
over the anterior cnd of the zooid, and a dark
patch down the dorsal surface of the branchial
siphon. Collector’s notes and photographs of
Philippine specimens (QM G1i2757, coll. MLE.
Cowan) indicate that living specimens were black
with fluorescent green rings around the siphons,
the ring around the branchial siphon being a wide
bund interrupted over the dorsal tubercle, while
the ring around the atrial siphon is a narrow band
around the rim of the aperture.

The basal part of the test is gelatinous and very
firm, ag is the test in the abdominal region, The
lesl over (he thoraces is softer and more
transparent, but never glassy. Zooids are separate
for varying parts of their length — sometimes the
abdomen or some part of it is embedded in
common test, or shares a stalk with another zooid,,
or olten the whole zooid is entirely separate. The
basal test often forms a massive or irregular stalk
for the colony. Colomies are often solid, the zo0id
stalks adhering to one another.

InreRWAL SrRucTURE: Zooids are large, 2cm
to 4cem long with the thorax and posterior eud
of the abdomen ubout 0.5em wide in fairly relaxed
zooids. However, strong longitudinal muscles
extend along the length of the thorax and abdomen
and vooids are often strongly contracted, The
posterior expanded part of the abdomen, contain-
ing the stomach and gonads, is about one quarter
of the length of the more relaxed zooids. The
remainder of the length is equally shared by the
thorax and the oesophageal neck. Thoracic
muscles are Conspicuous and strong, with formula
SE,3B,3D, When contracted, muscles from the
right side of the thorax swing around onto the
ventral part of the oesophageal neck and then onto
the left side of the posterior part of the abdomen.
Muscles from the left side of the thorax curve
dorsally and on to the right side of the abdomen.
There are four large branchial tentacles in an outer
circle and. anterior to these, an irregular
arrangement of more numerous middle-sized and
smaller tentacles. The opening of the neural gland
is a vertical slit on a large fleshy cushion. There
are 18 to 22 rows of 60 Lo 80 stigmata.

The oesophagus lacks @ prestomach. The
stomach as relatively narrow and pear-shaped.
sometimes. but not always, with one or 2 ridges
in the internal lining each side of the suture line.
CGionads are in the gut loop, The ovary has
particularly large egus. Embryos are crowded.
more or less in 3 rows in ihe upper half of whe

62 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic, 20, Clavelina robusta n.sp.: a, colony (holotype WAM 753.83): b, relaxed zooid (holotype QM GH2140);
e,d, contracted vooids from left and right respectively (QM G11934): e,f, zooids showing gonads and brooding
embryos (QM GH4074. holotype QM GH2140); g, larva (paratype WAM 755.83). Scales: a-f, 2mm, g, 0.2mm.

THE AUSTRALIAN ASCIDIACEA 2 63

oesophageal neck where the oviduct is expanded
to form a brood pouch, where embryos begin their
development, continuing it first in the distal end
of the oviduct across the posterior end of the
thorax and then free in the peribranchial cavity.

Larvae are large, the larval trunk being |.3mm
long. The tail is short, barely reaching the anterior
end of the trunk. The 3 adhesive organs are well
developed, with a relatively deep cup of ectodermal
cells around the axial cone. The ventral stalk
supporting the frontal plate is long, with small
rounded ampullae alternating with the bases of
the adhesive organs.

Embryos are present in colonies from Western
Australia and the Northern Territory collected in
September (QM G11934, GH4074) and from
Western Australia in April (WAM 753-5.83).

Remarks; The size of the zooids and colony,
the long narrow oesophageal neck, and the muscle
formula of this species are similar to Clavelina
australis. The latter species can be distinguished
by its median pigment patches, the absence of
brooding embryos from the upper part of the
oesophageal neck, as well as by its much smaller
larvae with a relatively long tail. Certain aspects
of the zooids and colonies resemble C. elegans
which, however, has fewer oblique muscle bands
and more longitudinal ones than does C. robusta.

The colour of the living specimens from the
Philippines (QM G12757) closely resembles that
of Clavelina viola. The latter species appears (from
its photographs) similarly dark, with white, yellow
or green spread over the thorax in speckles. In
the present species this colour is confined to sharp
bands around the siphons. Also Clavelina robusta
zooids are more robust.

Clavelina moluccensis: Tokioka, 1967a and
Podoclavella moluccensis: Millar, 1975 appear
specimens of Clavelina robusta n.sp., having
similar colonies, large zooids with a long
oesophageal neck, a similar muscle formula, large
larvae with small ampullae on the frontal plate,
and a short tail. The branchial tentacles and dorsal
tubercle of C. robusta are identical with those
figured by Tokioka (1967a, fig. 35d). Further, the
light area around the siphons in preserved
specimens from Western Australia (WAM 755.83)
is that part of the zooid which Tokioka describes
as having been a very bright yellow colour in life.
Clavelina moluccensis: Tokioka and Nishikawa,
1976 also appear specimens of C. robusta having,
in addition to the other characters listed above,
embryos in the upper abdominal part of the
oviduct and purple pigment persisting in the
anterior part of preserved zooids.

Genus Nephtheis Gould, 1856

Type species: Oxycorynia fascicularis Drasche,
1882

A monotypic genus of Clavelinidae with
completely embedded zooids in a conical, fleshy,
stalked head. The thick stalk contains a unique
three-dimensional vascular network. Replicate
zooids form in the terminal ampullae of this
network, Unlike other Clavelinidae the terminal
ampullae protrude from the vascular network at
the top of the stalk just below the zooid-bearing
part, rather than being distant from the zooids
at the base of the stalk; and the ampullae do not
separate from the vascular network prior to the
development of the replicates.

There are no divisions of the gut posterior to
the stomach although a prestomach is formed
halfway down the oesophagus. The branchial
tentacles are in a single circle on the edge of a
narrow velum, and are not numerous. Larvae have
the characteristic Clavelina form, being large with
triradially arranged adhesive organs consisting of
an axial cone of columnar cells surrounded by
a collar of enlarged epidermal cells on a stalked
frontal plate.

Nephtheis appears close to Clavelina. Zooids
of N. fascicularis have muscles confined to the
thorax as in C. cylindrica, as well as having the
same short gut loop, prestomach, and long colony
with zooids around the periphery of a central axial
stalk (although in C. evlindrica the zooids are not
completely embedded as they are in the present
genus). Further, although the nephtheid mesh-
work vascular cylinder is not present in the genus
Clavelina, in C. pseudobaudinensis the blood
vessels do extend parallel to one another up the
length of the stalk and terminate at the top as
they do in the present genus. The principal
distinctions between Nephtheis and Clavelina are
the vascular network, and the single circle of
branchial tentacles. Gonads of Nephtheis are
smaller than those of Clavelina. Although testis
follicles are larger, they are confined to the gut
loop and are more or less in a circle around the
ovary rather than spread around the outside of
the gut as in Clavelina.

Nephtheis fascicularis (Drasche, 1882)
(Fig. 21. Plate Sa-c)

Nephtheis (?) Gould, 1856, p. 16.

Oxycorynia fascicularis Drasche, 1882, p. 175. Millar,
1963a, p. 717. Nishikawa, 1984, p. 116. Monniot, 1988,
p. 205.

Nephtheis fascicularis; Tokioka, 1952, p. 100; 1970, p.
85, Millar, 1975, p. 209.

64 MEMOIRS OF THE QUEENSLAND MUSEUM

Coleliq thomsom Herdman, 886, 7 &,

Nephithew thomyont Sluiter, 1909, 9. 3p. Hartmever.
919 p. 121,

Nephthes thompsont Van Name, )918, p, 144,

Neplihets nialaversis Slititer, 1909, p. 36.

Nephtheis favifarmis Slutter, 1909, p. 39,

Dis PRAM LON

Niw Rercorhs. Western Australia (Braome, (9M
(9258, WAM $66.83 868.83 882.83), Queensland
(Martha Ridgeway Reef, QM GH280 GI12093),
Philippines (OM 12756 GH465 GH499)) Northern
Territory (Darwin Harbour), Australian coust (SAM
bh 2037).

Prryrousiy Reconnen Western Atstraba (Nerth-
western coust Millar 1963). Arafura Sea (Tokioka
1952). New Caledonia (Monniot 198%), Ponape J
(Nishikawa 1984), Philippines und the Sulu Sea (Gould
1856, Van Name 1918. Tokioka 1970, Millar (975).
Caroline ts (Drasehe 1442) tndonesia (Herdman 1486,
Sthunter 1909).

Dirse rie nan

EXTERNAL APPEARANCE, Colonics have firm
thick stalks. up to 3,Sem in diameter and 20em
long, although usually the stalk isin the vicinity
ol2 to Sem long. Sometimes many stalks are joined
by common basal test, from which additional
stalks arise. The diameter of the stalk usually
decreases toward the zooid-bearing head, The
heads are progressively spherical, conical. and long.
(up tu l6etn) and cylindrical, the head lengthening
as zooids are added from around the periphery
ol (ie Vasculac network at the top of the stalk.
The largest specimen of the newly recorded
material (WAM 866.83) is rope-like with a head
\6em long and the stalk |4cm. As ring after ring
of zoolds develop from the top of the stalk, the
vascular network expands behind them, filling the
centre of the head with an axiy that as a
continuation of the stalk, and that supports the
lenythening head of the colony, Thus a conical
to cylindrical head consists of an outer layer of
zooids, their abdomina projecting inwards toward
the vascular network of the central axis. Bach
zooid Maintains its connection with the vascular
network through its posterior abdominal stolon,
Smaller heads consist of hemispheres to cones of
zooids over the top of the stalk. their vaseular
stolons projecting down to jam the vascular
network that, atthis Stage, is contined to the stalk,

Several headless stalks are available from
Roebuck Bay (QM G9258), These narrow to a
point at their terminal free end. New zooids are
developing around the narrowing free ends. the
largest 2ooids at the Lop and the smallest further
toward the wider base, These appear regenerating
colonies in Which the zooids have either regressed
or have been lost through mechanical damage,

ii the newly recorded (material, long cyliidrical
and conical heads are [rom Roebuck Bay, broome,
while the specimens from the Great Barrier Reef
and the Philippines are all shorter, spherical, oval
or small cones,

The stalks are firm, although the vascular
network confers on them a spongy texture, There
is only a thin layer of test in the zooid layer of
the head and it 1s exceptionally salt.

INTERNAL SpRucTURE, Zooids lic in the colony
with their ventral sides toward the outside and
the base. The branchial apertures are turned
ventrally and open below the atrial apertures. Both
apertures are smooth. Zooids are about lem long,
the thorax longer than the abdomen, Thoracic
musculature, with formula 24£,4B,4D,3A, con-
sists of relatively short transverse and oblique
bands extending across each side from the atrial
siphon, the branchial siphon and the endostyle,
and attenuating over the dorsal and posterior
borders ol the thorax. Muscles do not extend onto
the abdomen, There are only 8 branchial tentacles,
produced from the edge of a narraw velum. ‘The
opening of the neural duct is a simple oval opening,

Newly recorded colonies have from 12 ta I4
rows ol sugmata. Zooids at the top of the large
heads from Roebuck Bay have 14 rows and these
al the base of the same head have 12 rows of
stigmata. Smaller colonics from Martha Ridgeway
Reef bave 13 rows in zooids at the lop and 12
in those at the bottom of the heads. About 30
stigmata are in each row. The gut loop is short.
A stall rounded prestomach li¢s halfway down
the oesophagus. and a rounded stomach, with a
suture Jine but no other structural folds or ridges,
is about halfway down the abdomen. No uther
structures dillerentiate any part of the gut, which
continues as a plain cylindrical tube extending
from the end of the stomach to the anus, (about
halfway up the thorax), Gonads are confined to
the pole of the gut loop posterior ta the stomach.
The central ovary, contaming up to & large eggs,
is surrounded by relatively large testis follicles.
A small incipient brood pouch oecurs at the
postero-dorsal corner of the thorax.

Neither embryos nor larvae were present im the
newly recorded specimens which were collected
in May, July and October. Tokioka (1952) records
up to 6 embryos in the brood pouch in specimens
trom the Arafura Sea in October, Larvae are large.
The trunk Imm Jong and deeper than long, ‘The
3 adhesive organs are of the usual clavelinid type
with a collar of cells around the central cone, and
they are triradially arranged on a frontal plate
(see Tokioka 1942),

Rimarks: In the newly recorded material the

THE AUSTRALIAN ASCIDIACEA 2 65

Fic, 21, Nephtheis foscieularis: ayo, colonies (QM GH2093 G12756); e. colony showing top of stalk with vascular
reticulum (QM GH2093); d, zooid (QM G9258). Scales: ajb, Smm; ¢, 2mm, d. mm,

66 MEMOIRS OF THE QUEENSLAND MUSEUM

large colonies with the stalk continuing up through
the head to form a central axis are all from
Roebuck Bay, Broome and there were no small
colonies without the vascular network continuing
up into the centre of the head recorded from that
location, Van Name (1918) reported long colonies
from the Philippines, up to nearly 20cm total
length, that he likened to ‘elongated pine cones’
(Van Name 1918, p. 144). Although he does not
mention the vascular network extending into the
head it is probable that it does.

Colour also varies in some colonies, The western
Australian ones are translucent (both living and
in preservative). All other colonies in the newly
recorded material are opaque blue, and this colour
persists in the preserved specimens which have a
conspicuous vascular network in the body wall
that is not conspicuous in the colonies from
Broome. However. Van Name observed similar
colour variations in his Philippine material. It is
likely that the variations in the extent to which
the vascular network of the stalk penetrates the
head, and in the intensity of pigmentation are,
respectively, due to age and intraspecific variation,
rather than genetic differences associated with an
indigenous Roebuck Bay species isolated from
populations in the Arafura Sea and to the
north.

Roebuck Bay colonies found at the extreme low
tide level, when exposed, continually drip water
(pers. comm. N. Coleman).

Herdman (1899) believed these Roebuck Bay
populations (see Saville Kent 1897) to be Colella
claviformis Herdman, 1899 (< Euclavella n.gen.
claviformis). Kott (1957a) suggested they could
be Sigillina cvanea. However, in both cases
similarities are only superficial and there are
differences in the colonies as well as in the zooids.
Both Herdman’s and Kott’s guesses were based
on the similar general shape of the colony which
consists of a strong, firm common stalk that raises
the zooid-bearing head off the substrate. This
colony type is found in other species of Holozoidae
and also in the Polycitoridae and the Polyclinidae,
and appears to be convergent.

The similarity of the colony and the zooids of
this species to those of Clavelina cylindrica has
been referred to above. The short zooid with short
thoracic muscles and short gut loop that is found
in C. evlindrica and Nephtheis fascicularis may
be a convergent adaptation associated with the
stalked rope-like colony with a layer of zooids
surrounding a central axial stalk. However the
presence of the prestomach and Clavelina-type
larva suggests a phylogenetic relationship as
well,

Family PYCNOCLAVELLIDAE new family

The family accommodates Pyenoclavella
Garstang, 1891 and the new monotypic genus
Euclavella, both containing species formerly in
Clavelinidae.

The new family is characterised by its relatively
small but thread-like zooids divided into thorax
and abdomen, smooth apertures, no internal
longitudinal branchial vessels, a long oesophageal
neck, smooth stomach at the posterior end of the
abdomen, and a posterior stomach in the pole
of the gut loop rather than (as in Clavelinidae)
in the descending limb. The anus opens at the
base of the atrial cavity (unlike the Clavelinidae
or Diazonidae where it opens some distance up
the branchial sac). A vascular stolon contains a
mesodermal septum. Gonads are reduced in size,
the testis consisting of a compact group of follicles
or (in one species) a single follicle. Only in
Euclavella n. gen. do they spread out over the
outside of the gut as they do in Clavelinidae. The
ovary is always small, containing no more than
about 6 eggs. Eggs are fertilised at the base of
the oviduct and develop as they move anteriorly.
The principal character separating the new family
from Clavelinidae is the unique larva with 2 or
3 long, tubular adhesive organs invaginated into
the anterior half of the larval trunk. They are
placed one above the other in the anterior mid-
line when 2 are present, but when 3 they retain
the primitive triradial arrangement. Prior to
settlement, or when pressure is applied to the trunk
of the mature larva, these tubes evert, projecting
out in the front of the larval trunk with the group
of adhesive cells formerly at the base of the tube
now on the tip of the everted organs. Larvae of
many species of Pycnoclavellidae are also unusual
in lacking an otolith in the cerebral vesicle.
However, this is not universal throughout the
family, and its absence may be a secondary
adaptation, associated with the long sticky
adhesive organs (Trason 1963).

Trason (1963) demonstrated similar tubular
adhesive organs in larvae of P. stan/eyi Berrill and
Abbott, 1949 as those reported for larvae of other
species known at that time, viz. P. aurilucens
Garstang, 1891 from the English Channel (see
Berrill 1947a) and P. minuta Millar, 1953b from
Africa. Larvae are now known for all subsequently
described species of Pycnoclavella, except P.
kottae (Millar, 1960) and P. aurantia n.sp., and
they all have these unique adhesive organs, as do
the larvae of Euclavella n. gen, They appear
unrelated to the stalked adhesive organs com-
monly found in Clavelina spp., which consist of

THE AUSTRALIAN ASCIDIACEA 2 67

a cone of columnar cells surrounded by a collar
or cup of epidermal cells. The long, invaginated
epidermal tubes of the Pycnoclavellidae could
have evolved only from a simple, sessile, non-
everting cionid-type adhesive organ,

Berrill (1947a) placed Pycnoclavella in Clave-
linidae, assuming the vascular stolon with its
terminal enlargement and mesodermal septum was
an indication of a similar method of replication
to that in Clavelina spp. However, Trason (1963)
showed replication in Pyvenoclavella was different
from that in Clavelinidae. She maintained, with
Pycnoclavella included, Clavelinidae was ‘an
artificial assemblage’ (Trason 1963 p. 323). Trason
(loc. cit.) demonstrated, in Pycnoclavella stanleyi
Berrill and Abbott, 1949, that although the
regenerating zooid remains connected to the
stolonic vessel] with its terminal expansion, it
originates from horizontal division across the
abdomen of the parent zooid; and the regenerative
process involves epicardial tissue as in many other
aplousobranch ascidians (but not in Clavelinidae).

Replication of Euclavella has not been inves-
tigated. The relationship between Euc/avella and
Pycnoclavella is, at this stage, based entirely on
larval form.

Larvae of species of both Clavelinidae and
Pycnoclavellidae are large, a characteristic of
viviparous larvae of colonial species (see Anno-
tated Glossary, above; and Kott 1985). Conse-
quently, these families have a long evolutionary
history as colonial organisms. However, at this
stage, there is no indication of a relationship
between the two forms of replication producing
colonies in Clavelinidae and Pycnoclavellidae
respectively; and therefore nothing to indicate if
replication had evolved in a common cionid-like
ancestor before either of these extant families
separated from it. In fact, only the possession of
smooth-rimmed apertures — a character that
otherwise occurs only in some zooids of the
Stolidobranchia simplified as a result of size
reduction (e.g. in Polyzoinae) — suggests a
common ancestor. Pycnoclavellid genera are
distinguished from Euherdmania (Polyclinidae),
which has similar larvae, and in which fertilisation
is at the base of the oviduct, by the clavelinid-
like characters of the zooids (smooth-rimmed
apertures, smooth stomach walls and absence of
a posterior abdomen).

In addition to the unusual larval adhesive organs
and probably the process of replication, the large
pigmented orange or green cells that so often
predominate in both zooids and larvae are also
characteristic of this family. In larvae these cells
are usually present in the test, and they subse-

quently amass in the tip of the vascular process,
and apparently colour adult zooids. Neither Berrill
(1950) nor Trason (1963) believed they were the
same as cells that Trason (1963 p. 311) observed
‘moving in the circulatory system throughout the
animal ,..’ and that are ‘seen in great numbers
in the abdomen of the oozooid before budding
occurs’,

Though records are few, possibly because
colonies are cryptic and usually not intertidal,
Pycnoclavella, found in Atlantic and Pacific
oceans, and in tropical as well as temperate waters
is especially well represented in Australian waters.
Euclavella is known by only one species recorded
from the coast of New South Wales and the North
Island of New Zealand.

Genus Pyenoclavella Garstang, 1891

Type species: Pyenoclavella aurilucens Garstang,
1891

The genus contains colonial species with
relatively small, partially embedded, or almost
separate zooids, with a short thorax and long
narrow abdomen. Eggs are fertilised in the base
of the oviduct and continue their development as
they pass up it to the atrial cavity. Larvae are
characteristic of the new family, Pycnoclavellidae,
having 3, or sometimes only 2, long, tubular,
eversible adhesive organs, The otolith is often, but
not always, absent from the larval cerebral vesicle
(see P. aurilucens, P. stanleyi, as well as P. minuta,
P. detorta and P. elongata n. sp.). However, a
small otolith is present with the ocellus in P.
arenosa, P. diminuta and P. tabella n.sp. Larvae
of some Pyenoclavella spp. (P. arenosa, P.
stanlevi, P. aurilucens and P, minuta) often (but
not always) have the epidermis at the anterior end
of the trunk thrown up into longitudinal ridges
(referred to as ampullae) and furrows (that form
pockets) around the adhesive organs.

Pycnoclavella is distinguished from Euclavella
by smaller zooids, fertilisation of eggs in the base
of the oviduct and partially separate zooids.

Probably Archiascidia is a synonym of Pycnoc-
lavella. Deflection of the dorsal ends of the
anterior and posterior rows of stigmata along the
mid-dorsal line, described below for all Prenoc-
lavella except P. elongata n. sp., has been noted
for Archiascidia neapolitana Julin, 1904 from the
Mediterranean (see Brien 1948). Brien believed it
a neotenous condition. However, the presence of
dorsal languets associated with these deflections
of stigmata suggest an evolutionary reduction in
size of the branchial sac rather than a persisting
embryological condition. It occurs in other small

MEMOIRS OF THE QUEENSLAND MUSEUM

68

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THE AUSTRALIAN ASCIDIACEA 2 69

(reduced) zooids, viz. Eudistoma and Cystodytes

(Polycitoridae) with 3 and 4 rows of stigmata,

respectively. It probably is convergent rather than

indicative of a phylogenetic relationship between

Pycnoclavellidae and Polycitoridae.

The genus can be conveniently separated into

3 groups of species, based on colony form:

1. Aurilucens group contains P. aurilucens from
the English Channel, P. minuta from tropical
western Africa, and P. arenosa, with acommon
basal test mass in which the posterior ends of
zooids are embedded. These species contain
large pigmented morula cells in the larval test.
Pycnoclavella aurilucens and P. arenosa, have,
respectively, green and yellow larvae and
adults. The colour of P. minuta is not known.
Larvae have longitudinal ridges (‘ampullae’) at
the anterior end of the trunk and adhesive
organs are not as deeply invaginated as in other
groups.

2. Stanleyi group contains P. stanleyi from
California, P. diminuta, P. tabella n.sp. and
P. elongata n.sp., with basal stolons but no
common mass of test. These species also
contain pigmented cells in the larval test, and
both larvae and adults are orange in all except
some specimens of P. diminuta — which have
blue, white, or brown adult thoraces. Longi-
tudinal furrows at the anterior end of the larval
trunk have been detected only in P. stanleyi.
Adhesive organs are always deeply invaginated.

3. Detorta group contains P. detorta, P. kottae
from New Zealand, and P. aurantia n.sp. with
thoraces turned through 90° Both P. detorta
and P. aurantia have orange pigment, although
the colour of P. kottae is not known. The larva
is known only for P. derorta. It has 3 long
adhesive organs and the oozooid is better
developed than usual with the gut loop
differentiated, longitudinal thoracic muscles
and 6 rows of stigmata.

Pycnoclavella is diverse in Australian waters.
Although zooids are small, colonies are striking
when alive. Consequently they have been photo-
graphed frequently by SCUBA divers. Pycnocla-
vella detorta and P. diminuta are tropical species,
while all others are temperate, possibly isolated
from tropical ancestors, e.g. Pycnoclavella
aurantia n.sp. is clearly related to P. detorta; and
P. tabella n.sp. to P. diminuta and both pairs
probably are sister species.

Key TO THE SPECIES OF PYCNOCLAVELLA
RECORDED FROM AUSTRALIA

1. Thoraces turned through 90°, the atrial

aperture terminal
Thoraces not turned through 90°, the branchial

aperture terminal ................-.... 3

2. Stigmata in 6 rows ........--+.4.. P. detorta
Stigmata in 8 rows ........ P. aurantia n.sp.

3, Stigmata in 3 TOWS .. ee cee ee eee eee eee 4
Stigmata in > 3 rOWS 6... .. 0. eee eee eee ed

4. Zooids thread-like, with less than 20 stigmata
PEE TOW sone nels me yess cee ea P. tabella n.sp.
Zooids not thread-like, with more than 20
stigmata per row ..........6. P. diminuta

5. Abdomina embedded in a branching axial
stalk; stigmata in 6 rows....... P. arenosa

Abdomina not embedded in a branching axial
stalk; stigmata in > 6 rows .......-....--
stand Sabb ta bgcind geet iht Seiee P. elongata n.sp.

The only confirmed species known from the
western Pacific and not yet recorded from
Australia is Pyenoclavella kottae Millar, 1960,
from the North I., New Zealand, distinguished
from P. detorta and P. aurantia n.sp. by its more
numerous (13 to 27) rows of stigmata.

Pycnoclavella arenosa (Kott, 1972)
(Fig. 22, Plate 5d)
Oxveorynia arenosa Kott, 1972b, p. 167,

DistRIBUTION

New Recorps; Victoria (Bass Strait, QM GH4226
GH4360).

Previousty Recorpep: South Australia (Investiga-
tor Strait — MV H168 holotype, MV H169 paratype
Kott 1972b).

DESCRIPTION

EXTERNAL APPEARANCE: Zooids are arranged
around cylindrical and irregularly branching
central common stalks 1.0 to |.75cm in diameter
and up to 9cm long. The outer layer of test,
through which pass the oesophageal necks of the
zooids, is sandy. Separate thoraces of the zooids
project out beyond the sand along the length of
the branching common stalks. The thoracic test
is free of sand and transparent. The central test
of the stalk, inside the sand, is soft, transparent,
and contains abdomina of zooids and their long
vascular stolons. In preservative morula blood
cells in the zooids (especially crowded in the
branchial sac) are dark and can be seen through
the outer coat of sand. The layer of test around
zooids contains circular brown plates resembling
the spherical bodies in the test of Pycnoclavella
diminuta, but more crowded.

Colour photographs of the newly recorded
specimen from Erith I., Bass Strait, show the
thoraces as yellow, but in preservative they are
purple-brown.

70 MEMOIRS OF THE QUEENSLAND MUSEUM

INTERNAL STRUCTURE: The zooids are less than
Icm long, the abdomen up to 4 times the length
of the thorax, Apertures are smooth-rimmed.
Twelve broad longitudinal muscle bands, with the
formula 3E,6B,3D on the thorax extend onto the
abdomen.

There are 6 rows of 20 rectangular stigmata and
the dorsal ends of the anterior and posterior rows
turn anteriorly and posteriorly, respectively, to
extend along each side of the mid-dorsal line. The
smooth, almost spherical stomach is in the
posterior end of the abdomen and an oval
posterior stomach is in the pole of the gut loop.
In all examined specimens the body wall around
the posterior end of the gut loop, and the space
enclosed by it, are crowded with the trophozooite
cells characteristic of a vegetative condition.

Up to 8 embryos line up in the oviduct in zooids
from the newly recorded colony from Bass Strait,
which was collected in May. Larvae are relatively
small (trunk 0.7mm long). The tail is wound three-
quarters of the way around the trunk. Just before
larval release it is curved up across the left side
of the anterior end of the trunk. Internal structure
is difficult to discern because of the dark blood
corpuscles in the larval test and haemocoelic
cavity. There is a large ocellus and a small otolith.
Two inverted, tubular adhesive organs at the
anterior end of the trunk are not as large as in
other species of the genus. At the anterior end
the trunk epidermis folds to form 8 long furrows
making ridges around the adhesive organs
(referred to as ampullae by Berrill and Abbott
1949, and Trason 1963). The furrows are filled
with the dark morula cells. There are 2 rows of
large stigmata.

Remarks: Colonies of this species are remin-
iscent of Clavelina cylindrica, with zooids
projecting out from cylindrical axial stalks.
However, in C. cylindrica the whole zooid projects
while in P. arenosa it is only the thoraces that
do. Further, both larvae and zooids of this species
share certain characters with other Pycnoclavella
that distinguish them from Clavelina. They are
smaller, have relatively longer abdomina, fewer
and shorter rows of stigmata with the anterior
and posterior rows deflected along the mid-dorsal
line, the stomach at the posterior end of abdomen,
and the posterior stomach in the pole of the gut
loop. Larvae are unusual, possessing an otolith
and shorter adhesive organs than usual. The
species is distinguished from others recorded from
Australian waters by its colony form and blood
cells that appear dark in preservative.

Pyenoclavella aurilucens, Garstang, 1891 (? <
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Fic. 22, Pyenoclavella arenosa: a, colony (holotype, MV
H168); b, zooid (paratype MV H169):; ¢, larva (QM
GH 4226). Scales: a, 5mm; b, Imm; ¢, 0.1mm.

the English Channel and P. minuta Millar, 1953b
from Africa have colonies similar to those of the
present species, with the posterior ends of the
zooids embedded in common basal test and at
least the thorax protruding from it, rather than

THE AUSTRALIAN ASCIDIACEA 2 71

being joined by basal connecting stalks as in P,
diminuta and related species. However, this basal
test is olive green and the tadpole larvae contain
green pigment, sometimes being uniform green
(Clavelina nana). In the larval test and adult zooids
of P. arenosa the morula cells that are purplish
brown in preservative are probably yellow in life.
They may be homologues of orange cells described
by Trason (1963) in the larval test of P. stanleyi
where they have the same distribution as in P.
arenosa. In P. arenosa the cells in the adult
circulatory system presumably confer the colour
on the zooids in the same way as its orange cells
affect the adult zooids of P. stanleyi (see Trason
1963).

Pycnoclayella aurantia n.sp.
(Fig. 23a. Plate 5e)
DisTRIBUTION
Tyree Locatrry: South Australia (Franklin L., Nuyts
Archipelago, !5m, breaking reef, coll. N. Holmes,
location C, February 1983, holotype QM GH2295),

DeEscRIPTION

ExterRNAL APPEARANCE: Colonies consist of
clumps of balloon-like heads supported on long,
thin, straight stalks arising from a mass of common
basal test up to 5mm thick. The-balloon-like head
is the thorax of the zooid, and the stalk is the
oesophageal neck, the lower half to one-third of
the abdomen being embedded in the basal test.
The free part of the zooids is up to Icm long,
of which the head is from one-quarter to one-
third. In life the expanded head is wider than
longer. However, the thorax is turned through 90°
on the top of the stalk (asin Pycnoclavella detorta)
so that the branchial siphon is on one side and
the atrial aperture is terminal. Thus the width of
the head is actually the length of the thorax. Living
specimens have uniformly orange stalks and
heads.

INTERNAL STRUCTURE: The body wall is delicate
and transparent. The ventral border of the zooid
curves down toward the top of the stalk, and
continues around the posterior end of the pharynx
to the oesophageal opening in the position usually
occupied by the retropharyngeal groove. Longi-
tudinal and oblique muscle bands have the
formula: 5E,3B,3D. Oblique muscle bands run
from the anterior half of the endostyle. In some
contracted thoraces oblique muscles are reduced
to 3. Longitudinal muscles and the most anterior
of the oblique ones extend onto the dorsal surface
of the abdomen and continue along it in a broad
band. Four more posterior, oblique muscle bands,
having crossed the posterior end of the pharynx
with the oesophageal end of the endostyle running

along it, form a band extending along the ventral
surface of the abdomen.

About 16 long, curved branchial tentacles, with
about- the same number of smaller tentacles
encircle the base of the branchial siphon. However,
these were difficult to count, and rudimentary
tentacles were not detected. The neural gland
opening is a simple, circular aperture projecting
into the pharynx.

There are 8 rows of about 50 stigmata. However,
the anterior and posterior rows of stigmata are
longer and extend along the mid-line where they
add to the area of the branchial sac, forcing it
out to form dorsal pockets or pouches on each
side of the dorsal lamina. Bands of unperforated
pharynx are both anterior and posterior to the
perforated area. The oesophagus is long, extending
along the right side of the rectum down to the
stomach in the posterior end of the abdomen.
Gonads are in the gut loop posterior to the
stomach. They consist of a small group of up to
5 ova in the middle of a mass of relatively long,
pyriform follicles. The testis follicles are mature
in the holotype, but the ova are not. Larvae of
this species are not known,

Remarks: The species differs from Pycnocla-
vella detorta in its having more rows of stigmata,
slightly fewer muscle bands, and uniformly orange
living colonies (instead of the iridescent green and
gold of the tropical species). It is probable that
P.aurantia is a sister species of the more widely
distributed tropical P.detorta.

Pycnoclavella detorta (Sluiter, 1904)
(Fig. 23b-e. Plate 5f)
Podoclavella detorta Sluiter, 1904, p. 6. Kott, 1957b,
p. 130.
Clavelina detorta; Van Name, 1918, p. 133. Millar, 1975,
p. 209. Monniot 1988, p. 202.

DisTRIBUTION

New Recorops: Western Australia (Cockburn Sound,
WAM 792.83; Geographe Bay, 13.84). Queensland
(Heron 1, QM GH4079; Wistari Reef, QM G9488
G11897, Philippines (QM GH527 GH529 GH532).

Previousty Recorpep; New Caledonia (Monniot
1988). Indonesia (Sluiter 1904). Philippines (Van Name
1918; Millar 1975). Red Sea (Kott 1957b),

The species appears to have a wide range in the tropical
western Pacific from the Philippines and south to the
Capricorn Group in the Great Barrier Reef, and on the
western Australian coast even further south to
Geographe Bay. It has been taken down to 40m.

DESCRIPTION

EXTERNAL APPEARANCE: Colonies consist of
large clumps of separate zooids up to 3cm long
arising from common basal test. The test over

72 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 23, Pyenoeclavella aurantia n.sp.: a, zooid (holotype QM GH2295), Pyenoclavella detorta; b, colony (QM
G11897); ¢, zooid (QM G11897); dye, larvae, one with a tubular adhesive organ everted (QM G9488). Scales:
a-c, 2mm; d,e, 0.5mm.

thoracic parts of zooids is delicate and in life this
is inflated and balloon-like. The test becomes
firmer over the long narrow abdominal stalk. The
branchial sac is bent over through 90° so the atrial
cavity and aperture are terminal, the branchial
aperture on one side, and the lower end of the
endostyle and the retropharyngeal groove with the

oesophagus and the rectum running alongside are
on the other side of the stalked head. The terminal
free end of the zooid has the dorsal lamina across
it and the oesophagus opening at its dorsal edge.

In preservative zooids are colourless, but in life
have greenish irridescent patches around the
branchial aperture and over the dorsal ganglion,

THE AUSTRALIAN ASCIDIACEA 2 73

a wide patch of orange across the dorsal surface
behind the base of the branchiul siphon, and
intense orange in the endostyle and in the whole
of the abdomen.

INTERNAL STRUCTURE The unusual orientation
of the thorax is readily observed in living zooids
owing to the bright orange of endostyle and
rectum, The thorax occupies only about one-
eighth of the total length of the zooid, the greater
part being the long oesophageal neck. The stomach
is at the posterior end of the body. The zowid
extends almost to the basal stelon, one or two
short vascular stolons lie at the posterior end of
the abdomen.

The body wall is delicate. Conspicuous muscle
bands, with the formula SE.4B.3D. extend from
the branchial siphon, the intersiphonal mid-lne,
and the anterior half of the endostyle to the other
side of the thorax (posteriorly positioned in these
eooids). Muscle bands trom the intersiphonal
space and the branchial siphon (longitudinal
muscles) crass the posterior end of the pharynx
where the endostyle continucs to the oesophagus
in the position usually occupied by the retropha-
ryngeal groove, Muscles then turn down to run
along the dorsal side of the abdomen in a band
with.some of the oblique muscles from the anterior
end of the endostwle. The more posterior oblique
muscles crass the posterior half of the endostvle
(the endostyle curving down into the stalk in a
deep arc or V) and then extend into a broad band
running down the yentral side of the abdomen,
Fine circular bands encircle each aperture,
Branchial tentacles are slender, in 3 circles, the
Most posterior one with the 6 longest alternating
with 6 of moderate length, and about twice the
number of rudimentary tentacles in the anterior
circle. The neural gland opening is a simple
transyerse oval or kidney-shape.

There are 6 rows of sigmata with about 24 in
a middle row, Although the endostyle is bent down
ina deep are and the dorsal lamina is straight
across the anterior end of the zooid, the anterior
and posterior rows of stigmata are not shorter
than the middle rows, the shorter distance between
each end of the endostyle and the dorsal lamina
being compensated for by the deflection of the
dorsal Stigmata along the mid-line dorsal to the
areas of unperforated pharynx anterior and
posterior to the perforated area. This creates
pouches that project up on each side of the dorsal
lamina at the dorsal ends of the anterior and
posterior rows of stigmata. The oesophagus is long
and narrow, extending down to a shield-shaped
stomach néar the posterior end of the abdomen
The stomach has u suture line but no structural

ridges or folds, Gonads, consisting of rather large
pyriform male follicles and a group of 5 ar 6 small
ova, he in the gut loop behind the stomach.

Embryos complete their development in the
atrial cavily al the lop of the free end of the zooid,
where up to 4 large tailed embryos can be found
ata time, all at different stages of development.
Embryos are present in colonics from Wistari Reet
in August.

Larvae are large, the trunk 1.7mm with a broad
tail that encircles about three-quarters of the
circumference of the trunk, The anterior hall of
the trunk is penetrated by 3 long tubular
invaginations of larval epidermis with the group
of adhesive cells in the base of the tube. When
these adhesive organs evert the front.of the trunk
hecomes flattened. Before release of larvae these
organs will evert if slight pressure is applied to
the trunk, even in the preserved material, An
ocellus but no otolith occurs in the cerebral vesicle,
The larval test lacks the darkly pigmented morula
cells found in P. diminuta, P. tabella n.sp and
P arenosa, There are five rows of short stigmata
in the branchial sac

Remarks. Ppcnoclavella aurania o.sp. from
South Australia and P. kottae Millar from the
North Island, New Zealand, appear close relatives
of this tropical species. Both have separate zooids
with the branchial sac turned through un angle
of 90°, however both have more rows of stigmata
— P. aurantia has 8 and P. kottae has trom 13
to 27.

Although developing embryos have not been
observed in the oviduct of the newly recarded
material, Van Name (1918 p. 134) reported them
to be present in the ‘proximal part of the abdomen’
as well as in the atrial cavity. Certainly in the
present collection embryos in the atrial cavity are
all tailed larvae, which have already have
undergone a period of development. It is most
likely that this began at the base of the oviduct.

The horn-like projections of the test reported
by Millar (1975) were not observed in any of the
prevent specimens, nat even those recorded trom
the Philippines.

Pycnoclavella diminuta (Kott, (957)
(Fig. 24. Plate 6a-1)

Clavelina diminuta Katt, 1957a, p. 89.

Pveroclavella dimituta: Millar, 19634, p, 715. Kott.
19726. p. 170 (part, not small specimen from Tipara
Reef < Pyenoctavella tabella nap.)

Clavelina rodula Katt, 1972b, p. 166.

Archidistoma richeri Moon, W988. p. 19a.

Archidistama rubripurctum Monniot, 1988. p. 200,

74 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic 24, Pyenoclavella diminura: ajb, colonies (QM GH1194 GH1302); ed, zooids (QM GH4083 G10162): e,
abdomen showing testis (QM G10162); f, portion of branchial sac showing posterior row of stigmata extending
posteriorly alongside mid-dorsal line (QM GH324); g, larva (QM GH4083). Scales; a,b, Smm: e-e, 1mm: fg.
0.5mm,

THE AUSTRALIAN ASCHDIACEA 2 75

Dis TRIM TION

New Recowos: Western Australia (Exmouth Gull,
OM GrH4083 GH4084; Shark Bay, WAM746,83 982.83:
Houtman’s Abrulhos, WAM 372.80, Rotiiest 1, QM
GH4089). South Australia (Great Australian Bight.
GH1283 GH I402 (FH2293 GH23N9), New South Wales
(Lord Howe 1,, QM GH53 GH4373 GH4377), Queens-
land (Heron f., OM ¢rif4081 GH4089; Lizard 1., QM
G10162 GI1994 GH324 GHI117). Northern Territory
(Darwin, QM GH4293). Philippines (QM GH457-8
CH492 GH534 (iH545-8 GH4109 GH41 12-3 GH4ITS).

Peevionsey Recorkorb, Wester Australia (Cape
Boileau Millar 1963u; Rottnest 1. — AM Y1193-
5 Kou 1957a), South Australia (Great Australian Bight,
Spencer Gull, St Vineent Gull SAM £2038 Kott
1972h), New Caledonia (F. Monniot 1988).

The spevics 6 known from 5 to 20m, usially in caves
and under ledges. It is apparently a lropial western
Pacific form extending around the Australian coust. The
collection of only a single amall colony from Heron |
ts Surprising in view of (he intensity OF collecting that
has taken place at that location,

DeseriPTion

Extpenan Armiarancts Living colonies con-
sist of a mass of spherical heads, about Smm in
diameter, on narrow straight stalks up to 2em long
that arise from a basal common muss of test, The
test on the stalks is gelatinous but rather firm and
almost opaque, while that on the head is glassy,
soft and usually mutilated in the preserved
specimens, In preservative the stalks are wrinkled
and thicker than in life with brown oily-looking
vesicles scattered through the test. These vesicles,
of various sizes, the largest in the internal test
against the body wall of the zooid, have not been
sven in the living colonies. which are yariously
referred to as ‘light globe’, ‘blue-pod’, “vellow-pod’,
‘brown-pod’ and *white-bead ‘ascidians, indicating
a wide colourdiversity. Uhis is sot associated with
ihe geographic location of the populations
sampled and docs not reflect morphological
differences. In the Philippines, collector's notes
refer to colonies as white. orange, purple and
blackish with white markings. There are both
brown and blue colonies from Exmouth Gulf;
South Australian colonies have white heads with
yellow slalks or are untormly yellow; and the
Lizard |. specimens are deep blue, The colour of
the single small colony collected from Heron I.
is not known. The pink colour noted in a small
colony trom Darwin (QM GH4293) may have been
caused by the masses of nauplius larvae of a
parasitic copepod.

The head contains the thorax of the zooid, in
lite expanded into the characteristic spherical
shape. The long, narrow abdomen occupies the
stalk and usually extends into the basal test mass.

INTORBAL Srrveture The body wall is
delicate, with distinct musele bands with formulae
SE 3B,3D (both blue and brown colonies from
Exmouth Gulf; 7E,7B,3D (Lizard 1). 4E4B.4D
(Heron 1,); 9E,L1B,6D (Great Australian Bight),
The number of muscle bands increases with size
and robustness of zooids — specimens from South
Australia being more robust than most others,
Muscles extend along the abdomen toits posterior
end, Branchial tentacles are in concentric circles,
6 larger tentacles posteriorly alternating with 2
smaller tentacles, Rudimentary tentacles were not
observed, although there is a circle of flat
projections of the body wall in the position where
they are usually found. The neural gland opening
ix a Simiple, Cirenlar aperture projecting slightly
into the lumen of the pharynx. A tongue-like flap
projects posteriorly along the mid-line behind the
prepharvngeal yroove.

There are 3 rows of 40 to 60 stigmata — the
count being done in the middle row — and an
expanse of onperlorated pharyngeal wall both
anterior and posterior to the perforated region.
The posterior row of stigmata on each side
continues posteriorly along the dorsal lamina into
the unperforated part of the pharynx, and the
branchial sac projects out on each side of the dorsal
lamina in this region, About 20 eXtra stigmata
are added lo the posterior row in this way. Four
dorsal languets lie across the dorsal sinus — one
each between the first and second, and the second
and third rows of stigmata, and 2 close together
on the posterior part of the dorsal sinus where
the extra sligmata are located. The oesophagus
is long, extending, alongside the rectum, to the
posterior end of the abdomen where the smooth-
walled, almost spherical stomach occurs. Inter
nally the stomach sometimes, but not always. hus
some fine lomgitudinal ridges. A short. relatively
flarrow infesting curves around in the postertor
end of the abomen and opens into the rectum.
There is a bilabiate wnus al the posterior end of
the atrial cavity, Gonads consist of a small bunch
of pyriform testis follicles in the posteriar end of
the gut Joop. ‘Two or 3 embryos are found in the
oviduct, although no more than a single egg has
been found in association with the testis follicles
in the loop of the gut. Eggs are fertilised at the
base of the oviduct and continue their development
as they pass up it, being found at progressively
luler stages of development.

Embryos were found in Lizard [, colonies
collected in November (QM GHLOI62), but not
in January, April or July; there were no larvae
wt Shark Bay colonics in April) South Australian
colonies had no larvae in March or April in 2

76 MEMOIRS OF THE QUEENSLAND MUSEUM

successive years. Apparently the breeding season
is restricted to late spring and zooids do not
produce many eggs — the ones they do produce
are large. The larval trunk is 1.75mm long. The
tail, which is particularly broad, just reaches the
anterior end of the trunk and its tip curves around
in the mid-line over the apertures of the 2
invaginated tubes of the adhesive organs. There
is an ocellus and a minute otolith. Crowded, darkly
pigmented morula cells lie in the larval test of
both trunk and tail, and, at the anterior ends of
the trunk, circular groups of cells appear identical
with the vesicles in the adult test. There are 2
rows of stigmata.

ReMARKs: The species is conspicuous owing to
its brilliant colours. It is surprising that it has not
previously been recorded from the tropical western
Pacific — possibly its spherical thoraces have been
mistaken for mollusc eggs. It is characterised by
its 3 wide rows of stigmata, the recurved posterior
row (which also occurs in P. detorta and P.
aurantia), the oily-looking vesicles in the test of
the stalk, and the large larva. An otolith is unusual
in Pycnoclavella, One occurs in P. tabella n.sp.,
a closely related species which has similar
inclusions in the test of the stalk. However a small
otolith as well as the ocellus occurs also in P.
arenosa n.sp. which is in a different species group
from the present species. This suggests that the
loss of the otolith is an intrageneric convergent
adaptation that occurs in parallel within the genus.

Specimens assigned to new species in the genus
Archidistoma by Monniot (1988), have all the
characteristics of Pycnoclavella, including the
larvae, viz. small otolith, 2 adhesive organs, long
larval trunk, and position of the anus at the
posterior end of the atrial cavity. They appear
synonyms of the present species.

Pycnoclayella elongata n.sp.
(Fig. 25. Plate 6g)

DisTRIBUTION

Type Locatity: South Australia (Franklin 1, Nuyts
Archipelago, just offshore N of West L., 8-l0m, rock
outcrops and some sand patches, coll. W. Zeidler, P.
Aerfeldt er al., 22.2.83, holotype SAM E1980; Franklin
L., Nuyts Archipelago, on rock amongst breaking reef,
15m coll. N. Holmes, paratypes QM GH4082, SAM
E1981).

DESCRIPTION

EXTERNAL APPEARANCE; The colonies consist
of clumps of elongate heads each on a narrow
straight stalk joined by basal stolons that tangle
and adhere to one another. Heads are about Icm
long and 4 to 5mm at their widest (halfway along)
and they narrow toward the stalk at their anterior

ends. Stalks of preserved colonies are about 8mm
long, but are wrinkled and probably are larger
in life, The test over the head is soft and flexible,
but firmer on the stalk. Both head and stalk of
living colonies are uniformly opaque orange.
Sometimes the lower half of the stalk and the basal
test are invested with sand. Apertures are close
together, on opposite sides of the narrow free end
of the zooid, and are turned away from one
another,

INTERNAL STRUCTURE: Zooids are between one
and 2cm long, of which the thorax is one-quarter
to one-third of the total length. The thoracic
muscles are strong with formula 10E,3B,4A. They
extend down along the abdomen. Six long,
branchial tentacles alternate with 2 moderately
sized ones in an anterior circle. A circle of minute
flat projections of the body wall anterior to these
2 circles of tentacles may be rudimentary tentacles.
The simple, circular neural gland opening projects
slightly into the pharynx,

There are 14 rows of stigmata with about 30
stigmata per row. The last row of stigmata is not
curved posteriorly along the dorsal lamina as it
is for many other species of this genus with a more
reduced thorax. The oesophagus is long, extending
to the smooth, round stomach at the posterior
end of the abdomen. Male follicles were not
detected. They may have matured before the ova.

Up to 10 large embryos in a developmental
sequence are present in a single line up the oviduct,
toward the thorax. The larval trunk is about Imm
long. Larvae have the usual 3 long, tubular
adhesive organs, triradially arranged, projecting
back into the trunk from the anterior end. An
ocellus, but no otolith, is in the cerebral vesicle.
A few dark morula cells occur in the larval test
of the trunk, and none in the test of the tail.

Remarks: The branchial sac is particularly long
and narrow for this genus, and the species can
be distinguished by its unusually numerous rows
of stigmata, with anterior and posterior rows not
extended along the dorsal mid-line. The colour
of the living zooids resembles that of Pycnoclavella
aurantia n.sp., Which, as well as having a different
body shape and number of rows of stigmata, has
differently oriented thoraces — the present species
having both apertures terminal while in P. aurantia
they are at right angles to one another, the
branchial aperture on one side and the atrial
terminal,

The species is possibly most closely related to
P. diminuta and P. tabella n.sp., having a similar
colony, but is distinguished from them by its longer
thorax, the lack of vesicles in the test, and the
crowded morula cells in the larval test.

THE AUSTRALIAN ASCIDIACEA 2 77

Fici. 25, Pyenoclavella elongata n.sp.: a, colony (holotype SAM E1980); b, single zooid isolated [rom colony
(paratype SAM E1981); c, zooid removed from test showing incubating embryos (holotype SAM E1980): d,
thorax showing muscles (holotype SAM E1980): e, gut loop (holotype SAM F1980): f, larva (holotype SAM
E1980). Scales: a,b. Smm; c, 2.5mm; dye, |}mm: f, 0.2mm.

Pycnoclavella tabella n.sp.
(Fig. 26. Plate 6h)
Pyenoclavella diminuta: Kott 1972b, p.170 (part, small
specimens from Tipara Reef),

DisTRIBUTION

Type Locaciry; Victoria (Portsea, on reef, 1.8m, coll.
N. Coleman, 4.6.77 holotype QM G10161). South
Australia (Tipara Reef, Spencer Gulf, 11m, coll.
Shepherd, 24.971, paratypes QM G9257, SAM E1982),

DESCRIPTION

EXTERNAL APPEARANCE: Colonies consist of
masses of thin, upright sandy stalks (1.5em high)
from which the soft sand-free thoracic parts of
the zooids protrude. The sandy stalks, all the same
height, have fine hair-like extensions of the test
to which sand adheres, and by which they adhere
to one another to form a sandy mass that, in life,
is covered with the crowded white spherical bead-

78 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 26, Pycnoclavella tabella, n.sp. (QM G10161): a, colony; b,c, zooids; d, posterior end of gut loop showing
testis between descending and ascending limbs; e, abdomen with gut loop removed showing testis, ovary and
incubating embryos in oviduct; f, testis divided into 2 lobes; g, larva. Scales: a, 5mm; b,e,e, 1mm; d, 0.5mm;
f, 0.1mm; g, 0.2mm.

like expanded thoraces. Basally, the sandy stalks
taper into fine stolons which connect zooids to
one another and have side branches that fix them
in the substrate. Beneath the adherent sand the
test of the stalk is slightly firmer than that of the
thorax, and has brown vesicles scattered through
it as in P. diminuta.

INTERNAL STRUCTURE: The zooids themselves

are thread-like, up to Icm long, with long vascular
stolons that extend into the base of the stalk. The
thorax is only about one-tenth of the length of
the abdomen. The body wall is delicate with
conspicuous longitudinal and oblique muscle
bands with formula 3E,3B,2D. Muscles continue
along the length of the abdomen. Apertures are
close together on the free anterior end of the thorax.

THE AUSTRALIAN ASCIDIACEA 2 79

There are 3 rows of up to 20 stigmata in the
small, narrow thorax. An expanse of unperforated
pharynx exists anterior and posterior to the
stigmata, with the first and third rows turned,
respectively, anteriorly and posteriorly along the
dorsal mid-line. The long oesophagus opens into
the small, spherical stomach in the posterior end
of the abdomen. The testis is in the loop of the
gut posterior to the stomach. It is a single, flat,
sometimes bilobed, follicle narrowing anteriorly
to the vas deferens. It is visible on the left side
of the gut loop. In both specimen lots examined
a series of up to 7 developing embryos occur in
the oviduct, progressively better developed as they
pass up the oesophageal neck to the thorax. Eggs
are produced one at a time. Fertilisation appar-
ently occurs just anterior to the stomach, where
short intervals of duct between the proximal 4
eggs stain blue in haematoxylin indicating that
sperm are present. In view of the narrow diameter
of the oviduct which the large, developing embryos
completely fill, sperm must be present toward the
base of the oviduct before ovulation begins, and
must persist there to fertilize the eggs as they are
produced. Oviduct and vas deferens are closely
associated for the whole of their length.

Larvae are relatively large, with a trunk 0.8mm
long and with the broad tail wound almost all
the way around the trunk. They have 2 inverted
tubular adhesive organs at the anterior end of the
trunk, in the median line. There ts a large ocellus
and a minute otolith. The larval test has brownish
pigment spots that probably develop into the
spherical bodies found in the adult test. The species
appear more prolific than most others in the genus.
Embryos are present in both June and September,
and are more numerous than in other species.

Remarks: The species is related to Prenacla-
vella diminuta, both species having only 2 adhesive
organs in the larva, a larval otolith, a terminal
branchial aperture. and the same brown vesicles
in the test of the stalk. However, the present species
is much smaller and less robust than P. diminuta,
has fewer stigmata per row, fewer muscle bands,
a sandy coat on the stalks, and a single, lobed
testis follicle. The otolith, like that of P. diminuta,
is minute and was overlooked by Kott (1972b),
as was the fact that there were only 2, rather than
3 adhesive organs. The same anterior and posterior
extensions of the first and third rows of stigmata
along the dorsal mid-line are present as in most
species of the genus.

Dumus areniferus, a species of the Euherdma-
niinae, has similar colonies formed by the close
adherence of small, upright, thread-like zooids,
each in its own covering of sand-invested test.

Genus Euclavella n.gen,

Type species: Colella claviformis Herdman, 1899.

The genus contains a single species. It has a
fleshy, stalked colony with completely embedded
Clavelina-like zooids regularly arranged and
opening to the surface all around the rounded to
oval head. Vascular stolons with a mesodermal
septum project down into the thick, fleshy stalk.
The branchial tentacles are in 3 concentric circles
as in Clavelina. Larvae have the tubular,
invaginated adhesive organs of the family
Pycnoclavellidae. There is a well developed ocellus
in the cerebral vesicle, but no otolith. There are
similar larvae with tubular adhesive organs and
no otolith in Pyenoclavella spp. and the Euherd-
maniinae. The closest phylogenetic relationship
for the genus appears to be with Pycnoclavella,
from which it is separated by its embedded zooids
and the presence of a brood pouch in which
fertilisation takes place. It is also distinguished
from Pyenoclavella by the firm, opaque test in
which the zooids are embedded, instead of the
layer of soft transparent test that covers the
thoraces of the zooids of Nephtheis and Clavelina
as well as Pyenoclavella, The test of the whole
zooid bearing head of the present genus is firm
and the form is maintained in preservative
irrespective of the condition of the zooids
embedded in it.

The only known species of this genus is recorded
from New Zealand and New South Wales.

Euclavella claviformis (Herdman, 1899)
(Fig, 27. Plate 7a—c)
Colella claviformis Herdman, 1899, p.67.
Clavelina claviformis: Kott, 1957a, p. 88. Millar, 1960,
p.68; 1982, p.12.
Amaroucium anomalum Herdman, 1899, p.76.
Clavelina sigillaria Michaelsen, 1924, p.269,

DISTRIBUTION

Niew Recorps. New South Wales (Jervis Bay, AM
Y2138: Port Hacking, AM Y2143; Port Jackson, AM
Y2131; Port Stephens, QM G10152), New Zealand (Bay
of Islands, QM GI0155).

Previousty Rrcorprp New South Wales (Port
Jackson — AM U241 UIS! G12248 syntypes Herdman
1899, AM U353 holotype A. anomalum Herdman, 1899,
AM Y1254 Kott 1957a; 11 mile S by E Ballina — AM
U577). New Zealand (North Island ZMC holotype
Michaelsen 1924; Millar 1960, 1982)

The species has been recorded from I5m down to
60m (AM U577).

DESCRIPTION

ExTerRNAL ApprarANce: Colonies have a
rounded to oval head up to 6cm long supported
on a short, thick stalk that sometimes expands

80 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic, 27, Euclavella claviformis n.gen.: a, colony (QM
G10152); b,c, zooids from right and dorsum
respectively, muscles partly removed (QM G10152);
d, larva (AM Y1254). Scales: a, lcm; bye, 1mm; d,
0.2mm.

basally to a wide and almost leathery holdfast.
Otherwise the test is firm and gelatinous through-
out, but firmer on the’stalk than on the head.
Several stalks may be joined basally. The stalk
expands where it joins the head. Vascular stolons
from the zooids extend down into the base of the
stalk. The zooids are embedded in the head,
opening all around its surface, the branchial
apertures anterior to the atrial openings, Living
colonies are yellow-green (AM Y2143) or opaque
white with orange zooids, the colour of the zooids
being apparent where their apertures project
slightly from the surface.

INTERNAL STRUCTURE; Zooids are always very
contracted, especially the abdomina, and their true
dimensions have not been determined. Probably
they are more than twice the length of most of
the preserved zooids, which are never more than
about 6mm. Thoracic muscles are widely spaced
oblique and longitudinal bands, with formula

3E,3B,3D. However, on the abdomen they are
much more numerous, completely surrounding it
and obscuring the other organs. There are 3 circles
of tentacles, 6 large ones in the most posterior
circle; about twice the number, moderately sized,
anterior to the larger ones, and in the most anterior
circle a variable number of rudimentary tentacles.
The neural duct opening is a small transverse oval,
projecting slightly into the lumen of the pharynx.

There are 10 rows of about 40 stigmata. The
stomach is about halfway down the abdomen. It
probably is smooth in the living specimens,
although when preserved it is collapsed into folds,
apparently artefacts. The gut is no further
differentiated after it leaves the stomach. It passes
forward to the bilabiate anus at the posterior end
of the atrial cavity as a cylindrical tube. Gonads
are present in the gut loop posterior to the stomach
and consist of a group of 3 or 4 small eggs
surrounded by fairly numerous testis follicles
which extend out over the left side of the abdomen.
Up to 8 developing embryos are in a brood pouch
at the postero-dorsal corner of the thorax where
they appear to begin their development. They are
present in colonies collected off the NSW coast
(AM Y2138 Y2143) in May and June.

Larvae are large, the trunk about 1.2mm, and
the tail is short, only about half the length of the
trunk, although the test covering it, forming the
fin, is longer (see Remarks, below). There is an
ocellus but no otolith in the cerebral vesicle. No
frontal plate develops, the anterior end of the trunk
is unmodified except for 3 triradially arranged,
tubular, adhesive organs invaginated into the body
of the larva, with adhesive cells at the base of
each tube. These become terminal when the tubes
evert and project out in front of the larva. The
bases of the inverted tubes converge in the centre
of the trunk, near the developing oesophageal
region,

Remarks: Despite the wide geographic sepa-
ration between the New Zealand populations and
those on the central eastern coast of Australia,
the only difference found in either colonies, or
zooids or larvae is that the New Zealand specimens
have a longer larval tail than the Australian ones.
At this stage, without further differences separ-
ating them, they are considered conspecific. The
colonies appear closer to Clavelina than to any
other known genus, but they are readily distin-
guished by the firm test of the head in which the
zooids are embedded, by the strong abdominal
musculature of the zooids, and by the remarkable
adhesive organs of the larvae, which were
completely misinterpreted when the material was
examined initially (Kott 1957a).

THE AUSTRALIAN ASCIDIACEA 2 3

Family HOLOZOIDAF Berrill, 1950

Colonies are soft and fleshy, either with a thick
stalk or forming sessile cushions or sheets, Zooids
are completely embedded. and arranged in

colonial systems which, with the exception of

Sivillina and Polvdistoma n.gen., are highly
organised cloacal systems. Branchial openings are
6-lobed. Atrial apertures are either 6-lobed or
large, plainetimmed openings with an anterior lip,

Thoraces are short. usually with 3 or 4 rows of

sUgmata, bul occasionally with 5 or 6. Longuud-
inal thoracic muscles are present, but they do not
always extend onto the abdomen. Oblique and
transverse muscles are not always present. The
gut loop is relatively short, the oesophageal! neck
is never long, and with few exceptions the stomach
is halfway down the abdomen rather than at the
posterior end as in Clavelinidae, Pycnoclavellidae
and Polycitoridae. The anus opens some distance
up the branchial sac. Posterior vascular processes
of the zooids extend down into the stalk (when
present) or into the centre or base of the colony.
They do not branch, and each has ether an
ectodermal or an endodermal (epicardial) rather
than mesodermal septum. [he posterior abdom-
inal stolon is Short and inconspicuous only in the
relatively thin, investing colonies of Sigi/lina
Janiasiana,

Gonads are contained either in the gut loop.
or in @ posterior abdominal sac Connected to the
vooid by a narrow neck, or they spill over behind
the gut loop into the top of the vascular stolon,
In many species large, pyriform testis follicles are
arranged in grape-like clusters, but in certain
Speozva and Distaplia only 4 to 6 long follicles
are arranged parallel lo one another to form a
barrel-shaped mass with the short yasa efferentia
joining the vas delerens at one end. The ovary
is relatively small, producing few, but large eggs.
In a few species (curtain Hypodistoma and
Polydistoma ngen., and Distaplia retinaculata
n.sp.) unusually large eggs are probably tertilised
at the base of the oviduct and rupture into the
test (where the embryos complete their develop-
ment) directly from the abdomen, In all other
known species eggs are tertilised and embryos
incubate in a broad pouch formed from a loop
of the distal part of the aviduct which projects
from the postero-dorsal corner of the thorax.
Larvae ure large. In all genera except Sieflina
and Hypodistoma adhesive organs are triradially
arranged, 2 dorsal and one ventral, at the anterior
end of the trunk, They consist of a relatively deep
epidermal cup surrounding a deep axial cone with
a hyaline cap (see Claney 1977). In Sigillina and

Aypodistoma there ate 2 of 3, more complex
compound adhesive organs in the median line, In
Sigillina midbergi Ue adhesive organs ure inverted
tubes, asin the Pynoclavellidae and Euherdmania.

Replication is by horizontal division of isolated
vegelauive stolons which contain a tubular septum
that is epicardial in origin, tt is a prolific process,
and the small. non-funetional replicates can be
seen moving vp trom the top of the stalk or base
of the colony to take their places as functional
yooidls atthe surface. Blastozooids also form trom
the epicardial tube in the oesophageal region in
larvae of Mypsixiozed (see Brewin 1959). Disiaplia
and some Sveozvd.

The structure of the vascular appendages and
the process of replication in Sycozed has been
investigated by Caullery (1909), Beneden and Selys
Longchamps (1913) and Salli (1925a, 1926): and
in Distaplia by Kawalevsky (1874), Salensky
(1893), Salli (1925b, 1928. 1933) and Berrill
(1935b, 1948b), Brien (1948) summarised their
findings. Im all cases, there 1s an ectodermal
vascular process, usually consisting of two
channels, that projects posteriorly from the left
side of the posierior end of the abdomen. In
Mstaptia there are Numerous short vegetative
stolons (stolons proliftres: Brien 1948), containing
a part of the left epicardial sac, These become
isolated from the zooid at the posterior end of
the abdomen near the vascular process but
independent of iL, In Syeozoa, long vegetative
stolons, that occupy the stalk of the colony, divide
progressively from their anterior Lo postenor ends
in a prolific replicative process, These stolons
contain an epithelial tube that Brien (1948)
thought epicardial although Caullery (1909) was
Not sure of its origin. Berrill (1935b) identified,
in Pixtaplia magnilarva, a Vurther replicative
process in which the remnants of the anterior tips
of the epicardial tubes generate buds following
resorption of the zooids, It is a process more or
less homologous with the replicative process ir
the larvae,

Sigilina and Hypodistoma differ markedly
from Syeezva und Disteplie, in having & single
posterior abdominal process. Like the vegetative
stolon of Syeazod it contains an epicardial sac
(Caullery 1909; Sigi/lina grandissina, welow).
Although the vegetative process of Sigi/ling his
uot been investigated, this posterior abdominal
process provides the site for a process al
replication similar to that knows for Sycozod (see
Caullery 1909). Colonies of all the stalked species

of Sivillina examined in the present study have

replicated zooids being added to the colony at
the top of the stalk, and, in some cases, isolated

82 MEMOIRS GF THE QUEENSLAND MUSEUM

buds are present in (he stalk. This would be
compatible with the production of rephcates by
horizontal division oot the isolated vegetative
stolan, ws is characteristic of Sveezod und
Distaplia, thus confirming Caullery’s (1909)
obseryations on Sigdlina australis.

As a resull of hus observations, Caullery (/oe.
cit.) believed Sigi//ina a member af the same farnily
(Distomidae Giard, 1872 Polycitoridue
Michaelsen, 1904) as Syeozoa and Distaplia.
Michaelsen (1930) characterised the genus
Sigiiina (in Polycitorinae of Clavelinidae) as
species with 3 rows of stigmata and embedded
woods, He divided the sublamily into § subgenera,
2 of whieh (Sigiina and Hiperiesdistomea) are
included in (he genus Sigi/lina as defined im the
present work, The stomach folds that Michaclsen
uscd to separate the subgenera Sigillina uni
Uy periadixtoma were probably artefacts and their
presence cannot be confirmed in the Australian
maternih Rott (1967), basing her arguments on
the larvae. assigned certain Syei/lna to Arapozoa
Brewin, 19562 and, on the basis of the brood pouch
und the vegetative stolon, assigned the genus to
Holozoinac. Lt is now clear that Alapozed ty not
distinct lrom Sisellina,

The intragenerie relationships in these 2 groups
of holovow genera (characterised by differences
in their vegetative stolons) arc reflected in other
characters, Relationships between Sycozea,
Dislaplia and Typsistozoda are close, all having
separate vaseuldc and vegetative stolons, cloacal
systems, similar short zooids, and larvae with
triradially artanged adhesive organs, Sigillina and
Mypadisioma are readily separated trom the 3
former genera by theit single posterior abdominal
stalan, 3 rather thun 4 or more rows of stigmata,
a 6-lobed atrial aperture, and large larvae with
complex cyerting adhesive organs thal are not
obviously relaied to those of the other group of
genera. Of the new genera described hereunder,
Neodistomta tgen, appears related to Disraplie,
and Polvelistoma ogen. has the 6lobed atrial
apertures and short zooids with posteriorly
oriented atrial siphons and horizontal gut Joop
of Aypodistoma. Mypsistezoa and Neodistamea
always have @ gastric reservoir in the duet ol the
gastro-intestinal gland. Many Disraplia species do
loo, and although S\cazea cerebriferntis is the
only species of Sreozva to have one, the fact that
iLoceurs at all is further evidence of the differences
between the 2 groups of genera in the Holovoidae
It is possible that their differences may be found
to justify (he erection of a new tamily to
accommodate the Siena and related penera
separately from the Holosoidae.

the genus //vpedivioma Vokioka, 19674. with
type species /vpodistonm deerrarum (Sluiter,
1895), was erected lo accommodate species with
cloacal systems and small zooids with posteriorly
directed atrial apertures and smal) abdomina
distinguishing them trom Sivilline, A relationship
(based on larvae) exists between /7, deerrarum and
related Species that have cloacal systems, and 5.

faniaxiana ond similar species that do not,

However the separation of Ayppoelistoma from
Nigillina 1s supported by the small vooids of
Hypodistoma with their posteriorly oriented atrial
apertures and short abdomina, by certain
differences in the larvae (see Mypedisrama below),
and by the pregence of the cloucal cavity,

Like Polydistoma, 2 of the 3 known species of
Hy pedistoma (H. ntirabile and H. vastunty have
especially lirge larvae that incubate in the test
following rupture from the abdomen. This occurs
also in Dixiaplia retinaenlata n.sp,. and is
convergent, related to the size of the egg relative
to the zooid. rather than an indication of
phylogeny.

Many authors have discussed the possibility that
Syeosed and Diytaplia are congeneric (Van Name
1945, Brewin 1953, Millar [960. Abbott and
lrason 1968), however, this would deny the real
difference represented by the long yegetative
stolon Lhaboccurs in Syeoced bul net in Dixtaplia,
Speezog can also be distinguished from Distuplia
by the long, often straizht-sided heads, always with
a stalk which sometimes is thin and leathery rather
than fleshy, and with parallel double rows af
vootds. There aré some species of Distaplia, with
single double row systems of zoos and a single
terminal Common cloacal opening. that resemble
Steozvd in the arrangement of their zowiels.
However, in these Distaplia, rows of 7oaids
continue aver the top of the head while in Syeezou
they terminate around the margin of the tap of
the head whieh is often flat, always free of zooids,
and Sometimes occupied by a large terminal cavity.
Except tor 2ooids at the top of the cloacal canals
which have atrial lips inserted into the rim of the
cloaeal apertures (see Millar 1960), the atrial lips
of Syeezoa vooids are not.as long as those of
Mistaplia and do pot have the tongue-like lobes
on the outer border that, in the latler species, are
usually inserted into the test around the rim of
the cloacal uperture. Further, in Syeazoa the
branchial lobes are reduced and often absent
altogether, there are very few abd delicate body
muscles, purastigmatic vessels are absent, rows of
stigmata are paired, the stomach wall is smooth,
there are no conspicuous divisions i the gut
posterior to the stomach, there is never a rectal

THE AUSTRALIAN ASCIDIACEA 2 83

valve, and the replicative process is more prolific.

Characters of the larvae of Sycozoa that
distinguish them from larvae of Distaplia are the
particularly deep axial cone of the adhesive organs,
absence of ectodermal ampullae at the base of
the conspicuous, smooth elliptical stalks of the
adhesive organs, and absence of a frontal plate
and an ocellus. In several Sycozoa the larval trunk
contains a long epicardial tube extending forwards
amongst the adhesive organs. Although it has been
proposed that Sycozoa are unisexual (Brewin
1953), only some. species of this genus are
apparently so, and in others the gonads mature
sequentially as in Distaplia,

The affinities of Holozoidae are problematical.
Polycitoridae Michaelsen, 1904 (> Distomidae
Giard, 1872) combined clavelinid, polycitorid and
holozoid genera in the one family which
Michaelsen (1930) and Huus (1937) changed into
2 subfamilies (Clavelininae and Polycitorinae) of
Clavelinidae Forbes and Hanley, 1848. Van Name
(1945) included the same genera in a single family,
Polycitoridae, defined as genera in which the body
is divided into thorax and abdomen, with the
branchial tentacles arranged in several concentric
circles, without internal longitudinal branchial
vessels, and with the gonads in the gut loop. Berrill
(1950) accepted Michaelsen’s (1930) view of
Clavelininae as a distinct subfamily, and also
separated Holozoinae from Polycitorinae, thus
recognising three subfamilies in the family
Polycitoridae. Differences in the structure of the
vascular stolon, the process of replication, the
organisation of the colony, the structure of the
larvae, and the presence or absence of a brood
pouch are the basis for the elevation of these
subfamilies to full family status, viz. Clavelinidae,
Holozoidae and Polycitoridae.

Holozoidae do not appear to have a close
relationship either with Clavelinidae or Polycito-
ridae. In addition to their smooth apertures,
unique replicative process, and lack of a brood
pouch constricted off from the thorax, Claveli-
nidae are separated from Holozoidae by their more
numerous stigmata (more rows and more per row).
larger gonads, more numerous eggs and embryos,
branching vascular stolons without longitudinal
muscles and with mesodermal septa, and smaller
larvae. Further, in the larval clavelinid, adhesive
organs are smaller and have shallower epidermal
cups than Holozoidae, 2 adhesive organs are
ventral and one dorsal rather than 2 dorsal and
one ventral as in Distaplia and Sycozoea and the
adult organs (especially the gut loop and pharynx)
are not so well advanced. Polycitorid genera
resemble Diazonidae rather than Holozoidae in

the lack of a conspicuous vascular processes, and
replication by horizontal division of the abdomen.
They have generally smaller embryos brooded in
the atrial cavity, and not in a brood pouch as
in Holozoidae. If Holozoidae comprise a mono-
phyletic group of taxa and Sigi/lina is correctly
assigned to it, a common ancestry with the
Pycnoclavellidae is not precluded (see below,
Sigillina).

The rupture of large ova directly into the test
for incubation, which occurs in certain holozoid
species, is universal in Didemnidae and probably
results from their especially large eggs relative to
the size of the zooids, Nevertheless, often there
are similarities between Hypodistoma and
Polydistoma (Holozoidae), and Arriolum and
Leptoclinides (Didemnidae) that may not be
convergent, and that suggest a possible lineage
for Didemnidae. The colonial organisation of the
holozoid Polydistoma n.gen. resembles that of the
didemnid Arriolum Kott, 1983 in which zooids
have a thoracic brood pouch and a similarly
oriented atrial siphon that opens into a large
concavity on the upper surface of the colony. The
vascular processes also resemble the simple
ectodermal processes of Didemnidae, and the
zooids of all these taxa have similar small,
horizontal gut loops.

Larval size and form, the small number
produced per zooid, the well developed brood
pouch, the relatively small zooids, the highly
organised colonies and, in all but Sigi/lina, the
highly organised cloacal systems suggest that
members of the family have a long evolutionary
history as vegetatively replicating colonial
organisms,

A brood pouch to incubate the few, but large,
embryos produced by each zooid represents a
different reproductive strategy from Clavelinidae
in which numerous, smaller embryos are brooded
in each atrial cavity. However, the smal] number
of eggs produced by each zooid is, to some extent
at least, compensated for by the number of zooids
produced by the prolific process of replication.
Species of Holozoidae form integrated colonies
in which the colonies (rather than individual
zooids) are the biological units. The site of
replication and the brood pouch are both isolated
from the zooids and neither replication nor
incubation prejudice the capacity of the zooids
to continue feeding and contributing to the general
operation of the colony.

Holozoidae contains 9 genera, of which Sigillina
Savigny, 1816 and Distaplia Della Valle, 1881
(nomen conservandum) are well represented in
Australian waters. Sycozoa Lesson, 1830 (includ-

84 MEMOIRS OF THE QUEENSLAND MUSEUM

ing Cyathocormus Oka, 1912) also is represented
in Australian shallow water communities and the
genus is now known to be more diverse than
formerly it was thought, there being 8 species
recorded, 5 of them indigenous. Sycozoa is one
of the few genera in the Australian ascidian fauna
with Antarctic rather than tropical affinities.
Polydistoma n.gen, and Neodistoma n. gen.,
described from Australian waters, appear indigen-
ous. Hypsistozoa Brewin, 1953 (polytypic)
previously known from the Peru-Chile Trench (see
Kott 1969), and New Zealand is now known to
occur in Australia. Only Protoholozoa Kott, 1969
from Antarctic abyssal basins is not represented
in Australia.

Key To THE GENERA OF HOLOZOIDAE
(* not recorded from Australia)

1. Atrial siphons present .........eeeee eee 2
Atrial siphons not present...........00008 4
2. "Stigmata in 3 TOWSs «Spies fe fat Fee Dea es 3
Stigmata in 5 rows ...... Polydistoma n.gen.
3. Cloacal systems present ....... Hypodistoma
Cloacal systems not present ........ Sigillina
4, Cloacal systems present ............e00008 5

Cloacal systems not present ..*Protoholozoa
5. Rows of stigmata grouped in pairs .. Syeozoa

Rows of stigmata not grouped in pairs..... 6

6. Gonads present in top of vascular process...
SSctew mates sce: sesyite ome oN Fine pats Hypsistozoa
Gonads not present in top of vascular pro- ..
COBS arnie de sce acne one hee the ab cle Wee aelg dcg 7

7. Branchial sac with 4 rows of stigmata.......
bittba belek each aban duh eg alebelete's Distaplia
Branchial sac with > 4 rows of stigmata.....

0 G5e Sede ihe 9 Fae oa s pantgiese Neodistoma n.gen.

Genus Sigillina Savigny, 1816
Type species: Sigillina australis Savigny, 1816

Colonies are fleshy, either with a round, or
conical, or long and cylindrical zooid-bearing head
supported on a wide, gelatinous stalk that
occasionally is joined to others basally; or they
are sessile cushion- or sheet-like. Zooids open
separately to the exterior or into common cloacal
cavities. Branchial and atrial openings both have
their borders divided into 6 more or less equal
lobes. Zooids are robust, the thorax and abdomen
of more or less equal length, and the stomach
about halfway down the abdomen. There is always
an appreciable area of unperforated pharyngeal
wall both anterior and posterior to the perforated
part. The anus opens a short distance up the atrial

cavity. Usually (with the exception of S. fantasiana
and S. nigra), longitudinal muscle bands extend
from the siphons down the length of the body
and some of the longitudinal fibres continue along
the length of the posterior abdominal process
which is often very long, extending down the stalk
of the colony when one is present. This process
contains the extension of the left epicardial sac.
Transverse thoracic muscles are sometimes (but
not always) present, mainly on the posterior two-
thirds of the thorax. A brood pouch usually is
attached by a narrow neck to the postero-dorsal
corner of the thorax, or to the side of the abdomen.
One large embryo broods at a time in all species
except S. fantasiana which has up to 3 in a sessile
brood pouch. The small and often inconspicuous
ovary and numerous testis follicles are present in
the gut loop. Eggs are fertilised either in the brood
pouch or at the base of the oviduct. All embryos
in the one colony appear to be at an advanced
stage of development before testis follicles mature.

Sigillinid larvae probably are not free swimming
for long, for in several cases (S. myjobergi, S.
grandissima n.sp.) the tail is withdrawn before
larvae are released from the brood pouch.
Although the thoracic brood pouch bends up to
lie just under the surface test as the embryos
mature, it is possible the large larvae are liberated
through the atrial aperture as they are in S.
mjobergi (see below) — rather than erupting
through the surface test of the colony. In those
species in which embryos develop in the test, larvae
probably are liberated through the surface test.

Larvae of Sigi/lina (with larval trunks from one
to more than 4mm long) include the largest known
in the Ascidiacea. There are 2 or 3 everting
adhesive organs usually in the vertical mid-line
at the anterior end of the trunk but sometimes
(in S. grandissima n.sp.) triradially arranged. They
are unusual, and especially well developed. The
central protrusion of each adhesive organ is
surrounded by a cup of ectodermal cells or is
depressed into the larval trunk. However, rather
than being an axial cone as it is in Distaplia (see
Cloney 1977), the central protrusion is a long, oval
platform or ridge. When everted the columnar cells
are in compound branching groups rather than
forming a compact conical or cylindrical mass of
cells as in most other everting adhesive organs.
The exception is S. mjobergi which has 2 long
invaginated tubes similar to those known in
Pycnoclavellidae and Euherdmania but unlike
those of other Sigillina.

Other characters of S. mjobergi are so sigillinid
that it is difficult to invoke convergence to explain
them. A relationship between S. mjdbergi and

85

THE AUSTRALIAN ASCIDIACEA 2

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86 MEMOIRS OF THE QUEENSLAND MUSEUM

Euclavella claviformis (in the family Pycnoclavel-
lidae) is suggested by their similar colonies and
larvae, However, the latter species, like other
pycnoclavellids, has smooth-rimmed apertures,
numerous rows of stigmata, a number of embryos
incubated in the atrial cavity, a relatively long
oesophageal neck and a mesodermal septum in
the vascular stolon — all characters distinguishing
it from S. mjobergi. An alternative hypothesis that
larval adhesive organs of S. m/jobergi are related
to those of other Sigi/lina in some way not yet
evident has the tempting corollary of a common
ancestor for Pycnoclavellidae and the genus
Sigillina,

The condition of the epicardial sacs in Sigillina
grandissima n.sp. provide further support for the
suggestion of a pycnoclavellid affinity for this
genus. The new species has conspicuous epicardial
sacs, which are not fused. Euherdmania clavifor-
mis (Ritter, 1903) is the only other known species
in which epicardial sacs are known not to fuse
(Berrill 1936) and Euherdmania’s affinity with the
Pycnoclavellidae is established through the
similarity of its long invaginated tubular larval
adhesive organs.

Species of Sigi/llina have more restricted
geographic ranges than are usual in the Ascidiacea.
The genus is known only from the Indian and
western Pacific Oceans and 7 of the 13 known
species are recorded only from Australian waters.
The genus ts also unusual in the number of tropical
indigenous species in the Australian fauna —
tropical species usually having a wider range in
the Indo-West Pacific (Kott 1985). However, the
occurrence of sister species in South African
waters may have resulted from speciation from
the tropical fauna rather than being indicative of
a Gondwanaland origin.

It is probable the large larvae with their long
incubation in the parent colony are not widely
dispersed, resulting in the isolation and speciation
of populations.

Close relationships between certain species are
evident. The known species fall into the following
groups:
|. Fantasiana group, containing S. fantasiana

from Cockburn Sound (Western Australia) to
Gabo I. (Victoria); S. nigra from New South
Wales; and probably S. digitata from South
Africa (see Millar 1964).

These species all form sessile, cushion-like
colonies rather than upright and usually stalked
ones of other species. The two Australian
species have much reduced vascular stolons
without apparent muscle fibres on them. The
principal characteristics of the group are found

in the large larvae with long, narrow ridges
of columnar cells depressed into the larval
epidermis, and a waist-like constriction
between the anterior adhesive apparatus and
the developing oozooid with its mass of yolk.
Both Australian species have a ring of unusual
spike-like ectodermal processes around the
adhesive organs. These ectodermal processes
arise in a band from the epidermis behind the
adhesive apparatus and reach the surface test
around the anterior end of the larval trunk.
They may be homologous with the fine tentacle-
like processes found in a single circle around
the adhesive organs in Hypodistoma.

Cyanea group, containing S. cyanea with a
range from north-western Australia south to
King George Sound on the western coast and
to Arrawarra on the eastern coast; S. australis
with a wide range around the Australian coast
from the Montebello Is and south across the
Great Australian Bight to Port Jackson on the
eastern coast; S. grandissima n.sp. from the
Dampier Archipelago to Cockburn Sound and
the Great Australian Bight; and S. signifera
from Rowley Shoals off north western Aus-
tralia, and on the eastern coast from the Swain
Reefs and to the north. The latter species is
the only one in this group that is recorded
widely in the western Pacific, viz. from
Indonesia and the Philippines.

Horizontal (transverse) muscles are absent
from the thorax in several species of the cyanea
group, viz. 8. australis and S. cyanea. However,
they are present in S. grandissima and S.
signifera, The longitudinal muscles continue
onto the vascular process where they usually
are conspicuous. Larvae are especially large.
with the secretory cells of the broad adhesive
organs forming large, circular or oval plat-
forms, and with large, wide, rounded ectod-
ermal ampullae around the anterior end of the
trunk. Probably S$. mohiusi (Hartmeyer, 1905)
from South Africa and Malagasy is a member
of this group.

Only S$. mjobergi, with its long, tubular, larval
adhesive organs; and S. psammophorus (Hart-
meyer, 1912) from South Africa with a sandy test
and 8 true stomach folds, do not have a close
relative amongst the known species of the genus.

to

Key TO THE SPECIES OF S/G/ILLINA
RECORDED FROM AUSTRALIA

|. Colony a flat investing sheet.............. 2
Colony not a flat investing sheet .......... 3

2. Larval trunk |.3mm long; colony < Icm
11) (el ce er S. fantasiana

THE AUSTRALIAN ASCIDIACEA 2 87

Larval trunk 2.0mm long; colony > lcm
DES hp Scrpsee bile tine bed late paral S. nigra

3. Colony numerous small flat-topped lobes ...
O00 OCR RIOR IAMOGTS 2. S. signifera
Colony not numerous small flat-topped
Mey S: 5 ecsiets ales lhe sib valde due Qa ee deo dad 4

4. Colony massive conical to lobed heads;
horizontal muscles on posterior two-thirds

of thorax ............ S. grandissima n.sp.
Colony narrow conical to cylindrical heads; no
horizontal muscles on posterior two-thirds

Of thorax as se l0d lt OR el eel pit Gee 5

5. Thoraces transparent ........... S. mjobergi
Thoraces not transparent.............005- 6

6. Stigmata per row about 20; living colonies
OTANBE igs a baie ata odlee elec’ S. australis
Stigmata per row about 30; living colonies

1) (| eS S. cyanea

There are 3 other species of this genus known
from adjacent areas:

Sigillina digitata (Millar, 1962) from South Africa
has massive cushion-like colonies 5 to 7cm thick.
The larval trunk is probably the longest known
in the Ascidiacea (Millar 1964: 4 to 4.3mm long).
The larval adhesive organs and ectodermal
ampullae resemble those of S. fantasiana and
S. nigra from southern and eastern Australia,
respectively.

Sigillina mobiusi (Hartmeyer, 1905) from South
Africa, Mauritius and Malagasy, has variable,
sometimes upright, stalked colonies and both
longitudinal and transverse thoracic muscles. It
is distinguished from S. grandissima n.sp. by
its smaller colonies and fewer (10) branchial
stigmata (see also Hartmeyer 1912; ? Millar
1962; Plante and Vasseur 1966).

Sigillina psammophorus (Hartmeyer, 1912) from
South Africa has an outer layer of sand, 8
stomach folds, and its affinities are not known.

Sigillina australis Savigny, 1816
(Fig. 28. Plate 7d,e)
Sigillina australis Savigny, 1816, p. 179, Caullery, 1895,
p. 832; 1909, p. 47. Michaelsen, 1930, p. 495.
Atapozoa marshi Brewin, 1956a, p. 31. Millar, 1960,
p. 83. Kott, 1972b, p. 168; 1975, p. 2.

Dist RIBUTION

New Recorns: Western Australia (Montebello Is,
WAM 989.83; Carnarvon, WAM 765-6.83 857.83, QM
GH2151-2; Houtman’s Abrolhos, WAM 773.83; Triggs
I. WAM 75.78 24.84 16.87 18.87 191.87; Cockburn
Sound, WAM 20.84. QM G9479; Cape Naturaliste,
WAM 132.75; Margaret River, WAM 778.83; King
George Sound, WAM 987.83), South Australia (Great
Australian Bight, QM GH944 GH947). New South
Wales (Nelsons Bay, QM G9634).

Previousty Recorpep: Western Australia (Sharks
Bay to Albany — Michaelsen 1930; Triggs I. — Brewin
1956a). South Australia (Great Australian Bight — Kott
1972b; Investigator Strait — Kott 1975). New South
Wales (Port Jackson — Savigny 1816). New Zealand
(North I. — Millar 1960).

The species has been taken down to 20m. It appears
indigenous; being recorded mostly from temperate
locations. However it does extend into the tropics on
the North West Shelf.

DeEscRIPTION

EXTERNAL APPEARANCE: The colonies are oval,
or conical, or long (up to 56cm) and cylindrical
zooid-bearing heads that are only slightly greater
in diameter than their fleshy stalks. Stalks are
longer than the head of juvenile colonies, about
equal to the length of the head in moderate sized
colonies, and very much shorter than the head
in well developed colonies with long cylindrical
rope-like heads, Zooids open all around the length
of the head, the branchial aperture uppermost and
the atrial aperture toward the stalk. The posterior
abdominal stolons extend through the centre of
the zooid bearing portion and down into the stalk,
New replicated zooids are added to the colony
at the top of the stalk. Zooids at the top of the
zooid-bearing part are the largest and at a later
stage of sexual maturity than those at the bottom.

Living colonies are orange or pinkish-orange.
In preservative the test is sometimes pinkish-grey
and translucent with cream to brownish zooids.

INTERNAL STRUCTURE: Zooids are about 5mm
long. Thorax and abdomen are of more or less
equal length, although the thorax is usually more
contracted than the abdomen in the preserved
material, The thorax is wide. Both apertures are
on short, cylindrical siphons on the anterior end.
There are about 15 longitudinal muscles on the
thorax, 9 radiating from the branchial siphon and
6 from the atrial siphon. Fine circular muscles
form an almost continuous sheet around each
siphon, but no transverse muscles are evident on
the thorax. Fine muscle bands extend from the
thorax, over the abdomen and onto the long,
posterior abdominal vascular stolon where they
usually are conspicuous. There are about 24
branchial tentacles in 3 concentric circles, the
largest in the posterior circle.

In the branchial sac there is an extensive
unperforated area both anterior and posterior to
the 3 rows of about 20 stigmata, Wide transverse
membranes between the rows expand into
triangular languets in the dorsal mid-line.

The gut loop is relatively short and straight.
The small, smooth-walled stomach is in the upper
third of the abdomen and there is an oval posterior

88 MEMOIRS OF THE QUEENSLAND MUSEUM

THE AUSTRALIAN ASCIDIACEA 2 89

stomach in the descending limb. The rectum is
yoluminous, terminating in a smooth bilabiate
anus that projects up into the atrial cavity. About
20 pear-shaped testis follicles lie in the gut loop.
Asmall egy can sometimes be found in the oviduct.
More often a single egg is found in the brood
pouch attached to the postero-dorsal end of the
thorax by a marrow neck, The egg is apparently
fertilised, and the embryo completes its develop-
ment, in the brood pouch. Eggs of zooids in each
colony appear to be fertilised and development
begun before testis follicles fully mature. One
colony (WAM 989.83) has fully mature testis
follicles and expended brood pouches. Brood
pouches still attached to the dorsal border of the
thorax bend up to lie just under the surface of
the test as the embryos mature. Tailed taryae ure
present in specimens collected in December [rom
the Montebello Is (WAM 989.83), in July from
off Carnarvon (WAM 765-6.83 and 857.83), and
in August from Triggs 1, (WAM 16.87).

Larvae are large, the trunk aboul 2mm long
und the tail about the same length. Developing
adult organs are at the posterior end of the trunk.
and a large yolk mass occupies the centre of the
trunk. The anterior one-third of the trunk is taken
up by the adhesive apparatus. In one colony
(WAM 765.83) larvae, although they appear to
he at the same stage of development, are of
different sizes, ranging from 1.2 to 2.0nim, There
are two long adhesive organs one above the other
m the anterior mid-line. Each consists of a long
strip of tall secretory cells arising from the base
of a narrow trough-like depression. As the embryo
develops, the larval epidermis along each side of
these adhesive orgaris is produced into a row of
4 or Srounded ampullae. and each adhesive organ
is produced forwards on a short wide stalk. The
strip of vertical secretory cells erupts when the
concave base of the trough, in which i Is
contained, everts, presumably as a result of
internal pressure applied through the haemococlic
cavity of the larval trunk, The groups of secretory
cells on their branching stalks then separate from
ane another to effect an attachment to the
substrate over as wide an area as possible.

Remarks. Apart from the colour of living,

colonies, this species resembles Sigi/lina cvanea
closely and preserved specimens in which the

colour ty lost cannot be readily distinguished (see
also Sluiter 1909, Hartmeyer 1919). Sigillina
ausiralis has shghtly less robust zooids, with
narrower thoraces and only abour 20 stigmata per
row, rather than the 30) stigmata per row in S,
cyanea, and the number of testis follicles in the
present species (about 20) is usually less than in
S, cvanea (30) to 40). Further, in the latter species
the test is slightly tougher, the zooids are more
firmly attached to it, and the muscles on the
posterior vascujar stolon are more conspicuous.
Clear morphological differences can be observed
in larvae, those of S. cyanea being much larger
(3mm) and haying more rounded adhesive organs
than the present species. Sigi/lina grandissima n.sp
and S. signifera have similar, though even larger
larvae. Specimens of the latter specics are distin-
guished by their flat-topped, lobed colontes.
Sigillina grandissima has distinctive granules in
the epicardial endothelium, and transverse
thoracic muscles.

Specimens from the type location of 4fapzea
marsht have all the characteristics of the present

species.

Sigillina cyanea (Herdman, 1899)

(Fig. 29. Plate 7fg)
Culella cvanea Herdman, (899. p. 70.
Eudistoma cvaneu Kou, 1957a, pe 79.
Eudistoma evaneunr Millar, 19634, p. 714,
Sigillina caerulea Shuytet, 1909, p, St, Harimeyer, 1919,

. aS.
Not Distoma caerulea Stuiter, 198, p, 14.
Not Ludistomu caerulewm: Plante and Vasseur, 1966,
p 147, Millar, 1964, p, 163,

Dis reren cron

New Recorpvs: Western Australia (Port Hedlatid,
WAM 986.83; Dampier Archipelago, WAM 784,83
786.83; Montebello Is. WAM 771.83 [4.87) Kendrew
L.. WAM 976.83; North West Cape, WAM 772.83;
Exmouth Gulf, OM G9480; Shark Bay. WAM 774 7,83

79,83 781.83 783.83 [5.87; Cervantes ].. WAM 177.87
185.87 192.87; Houtman’s Abralhos, WAM 224.88;
Dongara, WAM 990,83; Penguin 1. WAM 13.87. QM
GH4101; Cockburn Sound, WAM 127,75 150.75 165.75
175,75 864-82 7XO,X3 OX7-# N39, AM Y2132. QM G920H
G9479: Cape Naturaliste. WAM 167.87. King George
Sound, WAM 19,87). New South Wales (Cronulla, AM
Y2120; Nambucea Heads, OM G10008: Arrawarra, QM
69634). Queensland (Capricorn Group. QM GI1906
B).

Fic, 28, Sigillina australis: a, colonies (QM GH944); b, zo0id (WAM 75.78); ¢, carly larva (WAM 766,83); d.
adhesive organ, front view. showing central flat-topped ridge of groups of upright columnar cells, The rides
has Side branches connecting it with the surrounding cup-hke structure, and possibly strengthening and supporting
it (WAM 766.83); &, advanced Inrva with adhesive orguns everted (WAM 765.83). Scales: a, lem; b,e,e, 0.Some

d, 0. (mm.

90 MEMOIRS OF THE QUEENSLAND MUSEUM

Previousty Recorpep: Western Australia (Cape
Jaubert — Hartmeyer 1919; Triggs 1., Cockburn Sound
— AM Y1280-1 Kott 1957a). New South Wales (Port
Jackson — Herdman 1899). Aru Is (Sluiter 1909).

The species has been taken down to 150m. Although
the records are mainly from tropical locations, especially
off the northwestern Australian coast to the Arafura
Sea, it also extends into temperate waters of south-
western Australia as well as New South Wales. However
it has not yet been recorded from the southern coast
of Australia east of King George Sound.

DESCRIPTION

EXTERNAL APPEARANCE: Colonies have oval,
conical, or very long cylindrical rope-like heads
up to 70cm long and about 3cm in diameter. Fleshy
stalks are almost the same diameter as the zooid-
bearing head. Stalks are longer than the head when
the colony is small, the same length as the head
when the latter is oval or conical, but when the
head is long and rope-like the stalk is very much
shorter. Thus a colony of 70cm length has a stalk
of only 12cm, and a colony of 7.5cm has a Sem
long stalk. Basally the stalk may separate into very
short root-like projections that help it to attach
to the substrate. Occasionally broad stalks are
found with small regenerating heads (WAM
976,83),

Zooids open all around the head, the atrial
openings uppermost and the branchial openings
toward the stalk. The long posterior abdominal
stolons of the zooids project into the centre of
the colony and down into the stalk. The test is
firm and the anterior ends of the zooids, which
lie against the inside of the outer layer of test,
are firmly fixed to it, and are difficult to remove
from the colony.

Living colonies are indigo blue, The deep blue
pigment leaches out into preservative following
fixation. Colonies long in preservative have an
almost colourless test and dark, or blue zooids.

INTERNAL STRUCTURE: Zooids are about 4mm
long in contracted state, with the thorax only
about one-quarter of the length of the abdomen.
The posterior abdominal vascular stolons are
particularly long and conspicuous. A layer of fine
circular muscles surrounds each of the short
siphons. Longitudinal thoracic muscle bands are
conspicuous, about 9 radiating from the branchial
siphon, and 6 from the atrial siphon. These
longitudinal bands are less conspicuous over the
abdomen, where they spread out rather than
coalesce into a broad band. Fine muscle bands
continue along the posterior abdominal stolons,
There are 3 circles of branchial tentacles — about
16 in the two posterior circles and rudimentary
tentacles in the anterior circle.

The pharynx is broad with 3 rows each of at
least 30 stigmata. There is an expanse of
unperforated pharyngeal wall both anterior and
posterior to the perforated part. The oesophagus
is short and the relatively small, smooth stomach
is in the upper one third of the abdomen. A small,
oval posterior stomach is separated from the
proximal part of the rectum by a narrow
constriction in the posterior third of the abdomen.

The testis, contained in the loop of the gut,
consists of 30 to 40 follicles. Although a small
egg is sometimes visible in the oviduct, one has
not been observed in the loop of the gut, where
it may be obscured by male follicles. A single,
small egg apparently is fertilized and completes
its development in the brood pouch which is
separated from the postero-dorsal corner of the
thorax by a narrow constriction. Tailed embryos
are present in the brood pouches of the zooids
of colonies collected in October from Cockburn
Sound (WAM 988.83) and in August from Wistari
Reef (QM G11908). However, well developed
larvae were present only in colonies taken from
Rottnest I. in January (QM G9266).

The larvae are large, with a trunk about 3.3mm
long. The tail is only about the same length as
the trunk. It is fusiform, narrowing to its junction
with the trunk and becoming wide halfway along
its length. The developing adult organs are
crowded in the posterior quarter of the trunk. A
large yolk mass occupies most of the trunk. Two
adhesive organs are in the anterior mid-line, one
above the other. Each consists of a long, vertical,
oval concavity in the larval epidermis with a mass
of adhesive papillae rising from the centre of the
concavity. Probably as a result of pressure within
the larval haemocoel the concave base of the organ
everts and the papillae are thrown forward,
projecting from the front of the larva, and
spreading apart from one another on branching
stalks. The tips of the everted papillae extend over
an area of about 0.6mm diameter. An ocellus and
otolith are in the cerebral vesicle.

Remarks: Sigillina cyanea is mainly tropical,
being absent from the southern coast of Australia,
while the related S. australis is present across the
southern coast of Australia and extends north to
Port Jackson and Montebello Is on the eastern
and western coasts respectively. The species
overlap along the eastern and western coasts of
the continent. Apart from its blue colour S. cyanea
(especially the variations in the shape of the
colonies and the morphology of the zooids) closely
resembles the orange S. australis. However, S.
cyanea has more numerous stigmata, more
conspicuous muscle fibres on the vascular stolon

THE AUSTRALIAN ASCIDIACEA 2 91

Fic, 29, Sigillina cyanea: a, outline of colonies (WAM 776.83 3x783.83 778.83); b, colony showing zooids (QM
G9479), e,d, zooids from left, and postero-dorsal view with brood pouch removed (WAM 773.83); e, larva
(QM G9266); f, front view of adhesive organ showing groups of columnar cells depressed into the larval ectoderm
(QM G9266); g, everted adhesive organ (QM G9266); h diagrammatic section through larval ectoderm in vicinity
of an adhesive organ. Scales: a,b, Icm; e-e, 0.5mm; f,g, 0.1mm.

92 MEMOIRS OP THE QUEENSLAND MUSEUM

und zoids more firmly fixed in the test. Further,
S. evanee has a larger larva with oval groups of
adhesive papillae rather than the clongate lamella
of 8. ausrralis, As the embryos mature, the brood
pouches bend anteriorly toward the atrial aperture
to lie just inside the surface of the test. as in &,
australis,

Sigillina caerulea Sluiter 1898 from South
Africa, Mozanibique and Malagasy tsa different
species — possibly of Audistama with a
characteristically cudistomid larval truok 0.7mm
long brooding in the atrial cavity (see Millar 1962,
Plante and Vasseur [966),

Sigillina fantasiana (Kott, 1957)
(Fig, 30, Plate Sa)
budistomu fantasiana Rott, 19574, p. 7h.
slrapezed fantasiana: Kort, 1967, p. U87, 1972a, py 7,
1972, p LOR.

Dis baie tos

New Reeokos, Western Australia (Cockburn Sound.
WAM 863.83 OM GH2/20, WAM 936,83). South
Australia (Spencer Gulf, QM GH3704 St Vincent Gulf,
SAM &2082), Victoria (Portland; Gabo L. MV F5316!).

Prewiousty Recororn; South Australia (Great
Australian Bight — Kott 1972b; Spencer Gulf — Kott
19574. Encounter Bay -- Kott 19724a).

The species has been taken from 2 to Iden

Description

Extrewat Apert araner Colonies are flat,
circular to irregular investing cushions less than
lem thick and up to Sem in diameter with a
smooth, even surlace. The test is soft and, in
preservative. transparent, usually with dark
pigment particles, especially in the surlace lnyers,
This dark pigment is occasionally confined to the
zooids themselves and is eventually lost altogether-
Living specimens are bright blue throughout.
Zooids are evenly spaced, opening by branchial
and atrial apertures onto the upper surface of the
colony. Colonies are often found growing around
stems of seagrass (/ormesira),

INTERNAL STRUCTURE The 2oo0ids are about
5mm long. The thorax, in moderately contracted
specimens, is only about a third of the total length,
the abdomen being, relatively long for species of
ihis genus, The posterior abdomina) vascular
stolon is relatively short and delicate, and muscle
libres were not always detected on it, About 10
longitudinal muscle bands on the thorax radiate
from the apertures and posteriorly extend down
each side of the abdomen, converging to a point
on each side of the mid-ventral line at the level
of the posterior end of the gut loop, The slender
vascular stolon projects from the abdomen
between the two slightly protruding points where

muscles converge und terminate. There are also
about 12 transverse muscle bands on the thorax.
These exchange fibres with the longitudinal bands,
In the branchial sac are 18 long narrow sligmata
in each of 3 rows and an area of unperforated
pharyngeal wall anterior and posterior to the
perforated area-

The oesophagus is relatively long — the small,
spherical stomach and an oval posterior stomach
being present in the posterior third of the
abdomen, The rectum extends from the pole of
the gut loop to about half-way up the thoras,
A mass of male follicles in the gut loop spread
out over the left (dorsal) side of the intestine.
Outside the testis follicles is a group of 3 to 5
small eggs. Eggs probably ure fertilised in the
upper (distal) part of the oviduet — in the ppper
part of the abdomen — where 3 embryos, at
different stages of development can be found
jncubating, the most anterior being the smost
advanced. A marked difference in size exists
between the incubating embryos in the expanded
part of the oviduct (which forms a brood pouch).
each successive one heing about twice the size of
the oné posterior to it, Embyros protrude from
the zooid its they develop, but the brood pouch
is MOL constricted off from the rest of the zooid.
Developing embryos are present in specimens from
Cockburn Sound in November (WAM 863.83
936.83), Spencer Gulf in May (QM GH3704), St
Vincent Gulf in Oerober (SAM E2082), Wright
1, (Encounter Bay, SA) in November, and Gabo
1, (MV F53I61) in May. In fact, the species
apparently broods embryos throughout the year.

Larvae are large, the larval trunk being 1.3mm
long and almost spherical. The tail is relatively
long, being wound about three-quarters of the way
around the trunk. Adult and larval organs are
well developed with 3 rows of jong stigmata, a
large cerebral vesicle with ocellus and otolith and
a well-formed gut loop. Two long narrow adhesive
organs lie in the mid-line anteriorly. This anterior
part af the larval trunk is separated from the more
posterior part (containing the adult orgams) by
a constriction or Waist. Each adhesive organ
consists. of a narrow, vertical strip of parallel
secretory cells rising from a concavity in the
anterior end of the larva. A ring of uniform, long,
spike-like processes arises from the ectoderm at
the base of the adhesive organs and encircles the
anterior end of the larva. There are also 3 rounded
ectodermal ampullae on each side, just posterior
to the ring of spike-like processes, one each side
of the mid-ventral and mid-dorsal lines, respec-
tively, and one opposite the space between the
two adhesive organs.

THE AUSTRALIAN ASCIDIACEA 2 93

Fic. 30, Sigillina fantasiana: zooids, a, from left with embryos, and b, from right without embryos (QM GH2120

GH3704): ¢, larva (QM GH2120). Scales; a-c; 0.5mm.

Remarks: Chis species with S. nigra (see below)
and probably S. digitata from S. Africa (see Millar
1964) is a member of the fantasiana species group,
characterised principally by the laryae with
ectodermal spikes around the long, narrow
adhesive organs, relatively small ectodermal
ampullae and a waist dividing the anterior and
posterior ends of the laryal trunk. The fine
ectodermal processes that encircle the adhesive
organs are in a single ring in §. fantasiana but
are in a wide band in S. nigra. These may be
homologous with the ectodermal process ina circle
around the adhesive organs in Hypodistoma.
Similarly large larvae with large adhesive organs
(depressed into the anterior test) aecur in
Hypodistoma although the waist is not present.
The intense blue pigment in both §. nigra and
the present species resembles that of S. cyanea.
The colour of S. digitata has not been recorded.

The method of replication in this species
deserves investigation, and it should be noted that

accessible populations occur at 3 to 4m off
Whitford Beach, Cockburn Sound, Western
Australia.

Sigillina grandissima n.sp.
(Fig. 31. Plate &b)

Dist rRigutioN

Tyre Locacrries: Western Australia (northwest of
Rosemary I., Dampier Archipelago, 70-72m, 3.12.79,
holotype WAM 846.83 QAf GH2/14, northwest of
Carnac |., Cockburn Sound, 3.4m, on reef, 7.12.77,
paratype WAM 782.83). South Australia (Topgailant
J, Great Australian Bight, [-7m, coll, S. Shepherd er
al., 29.3.82, paratypes QM GH1305, SAAT £1983).

Furrace Recoros: Western Australia (northeast of
Montebello ls, WAM 985.83; Northwest Cape, WAM
772.83, Houtman’s Abrolhos, WAM 95,78 370.80 767.83
830.83 192.88 195-6.88 219.88: Cervantes L, WAM
183.87 186-7.87). South Australia (Great Australian
Bight, OM GH4150).

The species. has been taken from 3m down to 72m
from the northwestern shelf of Western Australia and

Oe MEMOIRS OF THE QUEENSLAND MUSEUM

southtu Cockburn Sound, Although there are no records
from south of Cockburn Sound, it is probable that its
range is Continuous around the southwestern eorner of
Avstralia to Topgallant |, in the Great Australian Bight.

Drscrivtien

ExTERNAL Apprarascre Colonies are single
undivided conical to rounded lobes an short, wide
stalks; or massive subdivided colonies, narrowing
to a sbort stalk but with the individual lobes of
the zooid-bearing heads tending to flatten and
expand rather than narrow toward the top,
Smaller lobes are rounded in section throughout,
without appreciable difference im the diameter of
the zooid-bearing heads and their stalks, The
largest colony (WAM 846.83) is divided inte 6
lobes arising from a common base: the colony
is dhout Idem wide and l0em high: and the
separate lobes are about 3 to dem diameter
throughout,

Zooids, opening all arquad the upper half to
three-quarters of each lobe, become smaller
toward the base where the new vegetatively
produced yooids are being udded to the colony.

Living colonies from South Australia are
described as bright orange zooids in aclear matrix,
In preservative the zooids are often blue, although
sometimes that colour is lost. The preserved test
is translucent-or, in a few colonies, it is hard and
opaque,

INTERNAL StRucTURE. Zooids are about 5mm
Jong, the thorax and abdomen of about cqual
length, In addition, there is a conspicuous, long
and strong vascular stolon, The thorax has about
16 longitudinal muscle bands that radiate (rom
the siphons along the length of the body. and
extend onto the vascular stolon, forming a band
along cach side. About LO transverse muscle bands
run dround the posterior LWo-thirds of the thorax.
Bight large, hut sometimes stumpy. branchial
tentacles encircle the base of the branchial siphon,
in front of these are 2 circles of progressively
smaller tentacles. There are about 2() long stigmata
in each of 3 rows, and a strip of unperforated
pharyngeal wall anterior to the stigmata,

The oesophagus is about one-third of the length
ol the abdomen, the round, smooth stomach being
in the middle third and the small posterior stomach
in the posterior third. Gonads are in the gut loop
and are remarkably large and conspicuous for this

genus, especially the testis, whieh has numerous
follicles spreading out over the gut. In specimens
with immature testis, the male follicles can still
be observed ay a dense clump of follicles on the
left side of the pole of the gut loop, against the
rectum. A group of 2 or 3 ova lie in the abdomen,
A single embryo develops in a brood pouch
separated from the thorax by w narrow neck.
The most striking characters of this species are
the epicardial sacs formed of dark, bluish-black,
squamous epithelum, the colour derived Irom
dark, intracellular, melanin-like granules. The left
and right sues, cach with a narrow anterior horn
that partly encircles the oesophagus at the
posterior end of the thorax. meet, but do not fuse,
ventral lo the oesophagus, These sacs extend down
the ventral surface of the abdomen appearing as
a darkly coloured strap that protrudes into the
gut loop and between the stomach and rectum
The left sac terminates blindly just posterior to
the pole of the gut loop, The right sac swells oul
to a balloon-like expansion just posterior to the

stumach. but ity diameter decreases abruptly und

it becomes a flattened tube at the top of the
vascular process, This flattened tube forms the
septum between the two blood channels along the
whole length af the long, tough vascular process.
In the adult zooids, the anterior horn of each sac
terminates close to, but apparently does not open
into, the pharynx, although it does in the larva,
The dark intracellular granules are sometimes
present m the endodermal cells of the pharynx,
especially along each side of the endostyle and
lining the stigmata, This darkly pigmented
epicardial epithelium oceurs in all the preserved
newly recorded specimens except the holotype, in
which the epicardial sacs are conspicuouy and
pigmented only in the larvae,

Mature larvae are present inthe holotype colony
(collected in December) and in a specimen from
Cervantes |. (WAM [83.87) collected in May.
Tailed embryos, although not fully developed
larvae, are presenCin the Abrolhos (WAM 196.88)
and South Australian specimens (QM GH1305,
SAM E1983) collected in March. Larvae are
robust und their test is tough and firm. The larval
trunk is 3.5mm long, and the tail barely reaches
to ity anterior end. There is the usual otolith and
ocellys in the cerebral vesicle, which is far back

Fie TL, Siviliina grandissima qspy tec, colonies (hololype WAM 46.84, paratype WAM TAKS, 76783), de
g. /Ooids and parts of zoids, with epicardial sacs shown in darker shadings (paratype QM GH1I305 S4M
EIUNA) W larva (holotype Of GH2/ 14), ig. front view of larvae showing adhesive organs and ampullae,
diagrammatic (WAM 846.83): k, diagrammatic section through an everted adhesive organ, Seales: ae, 2em;

d-j, |i,

THE AUSTRALIAN ASCIDIACEA 2 95

96 MEMOIRS OF THE QUEENSLAND MUSEUM

on the upper surface near the base of the tail.
There are 2, 3 or 4 adhesive organs. When only
2. they are arranged, us in S§. ausra/is, in the
anterior mid-line; when 3 are present they have
a Uriradial arrangement, the dorsal one vertical
in the median line and the 2 ventral ones

<—_
2
=|
=
SS
‘ ‘ .
\

y

| < * 5)

B

\} MV T>
Ke Na
Pay! FRE)
AWN! |)

Fro, 32, Sigillina mjobergt: a, colony (WAM 155.57);
b, zooid showing its orientation in the colony,
semidiagrammatic: e, 7ooid yiewed (rom anterior end
(WAM 860.83); d, abdomen (WAM (29.75); e, larva
(QM GH2122), Seales: a, 2em; b,c, mm; de, 0.5mm.

symmetrical and radiating away from the centre
of the anterior end of the trunk. A fourth, or
accessory adhesive organ, Is sometimes present
belween the symmetrical ventral ones. The
adhesive organs develop in a similar way to those
of S. australis — with the differentiation of a group
of secretory cells in the base of a concavity at
the anterior end of the larval trunk. In the larvae
of the present species each adhesive organ, with
its concavity containing the secretory cells, is
produced forward on a short stalk. On settlement,
the concavity everts, forcing the secretory cells
forward and spreading them away from one
another.

Also, large, flat, forward-projecting ectodermal
ampullae are developed from the larval ectoderm
around the base of the adhesive organs (as in S.
australis and §. signifera). There are 3 on each
side, the middle one horizontally flattened and
the dorsal and ventral ones laterally flattened.

Remarks, The long vascular stolons which are
sufficiently strong to be pulled tram the colony
without the risk of breaking, and the huge larvae
(the second largest known in the Ascidiacea) are
unique features of this species. The darkly
pigmented wall of the epicardial cavity is also a
most distinctive feature, as is the large lestis with
numerous follicles spreading out behind the gut
loop,

Sigillina digitata (Millar, 1962) from South
Africa has similar colonies to those of the present
species. The South African species has smaller
(3mm) zooids, shorter stigmata und larger larvae
with long narrow bands of secretory cells and
without the large rounded ampullae of the present
species.

The affinities of S. granedissima are probably
with the cyanea group, its larva resembling those
of S. australis, S. cyanea and S. signifera. The
orange of living colonies resembles. that of S,
australis although the blue in the preserved zooids
resembles the blue of S. cyanea zooids that have
been preserved for u long time. However, the
thorax of the present species has transverse
muscles — a character not shared by either S-
cyanea, S. australis or S. signifera.

Sigillina mjobergi Hartmeyer, 1919
(Fig. 32)
Sigillina mjohergi Hartmeyer, 1919, p. 117.

Distieru ion

New Recorps. Western Australia (Port Hedland,
WAM 1005.83, Dampier Archipelago, WAM 124.75
OM GH82U, WAM 144,75: Montebello Is, WAM 860-
1.83 OM GH2!22 GH2104, WAM 99] -2,83; Jurien Bay,
WAM 994.83, Geraldton, QM GH4221; Dongara,

THE AUSTRALIAN ASCIDIACEA 2 97

WAM 993.83; Cockburn Sound, WAM 9,75 787,83).

Previousty Recorpep; Western Australia (Cape
Jaubert — Hartmeyer 1919),

The species has been recorded down to 140m and
it has not been taken from less than 30m. This may
be the reason for the relatively few records and the limited
known range, viz. the north-western continental shelf
of Australia.

DESCRIPTION

EXTERNAL APPEARANCE: Colonies consist of a
cylindrical to club-shaped, glassy, transparent
zooid-bearing head, not more than 6cm long and
3cm in diameter. It narrows basally to a long (up
to 8cm). narrow, hard, leathery stalk that divides
into root-like processes at the point of attachment
to the substrate, Several heads in the present
collection (WAM 860.83) do not have a stalk and,
like the type material (Hartmeyer 1919), are either
sessile, or have been separated from the stalk
during collection. Zooids, about 4mm apart from
one another, are arranged in parallel vertical rows,
each zooid alternating with those in adjacent rows.
As is usual for zooids in stalked colonies of most
taxa, they are upside-down — the endostyle and
branchial aperture below, and the dorsal border
and the atrial aperture above. The thorax is
perpendicular to the surface of the colony and
the abdomen curves down toward the stalk. Large
embryos often are present in the brood pouch lying
above the zooid.

Zooids are firmly fixed in the firm test of the
glassy head. Consequently they are impossible to
remove entire from the colony and they do not
contract on fixation. In preservative the fully
expanded thoraces are clearly visible and the
colonies are spectacular. The zooids become
smaller toward the base of the head where new,
vegetatively produced zooids are being added. The
posterior vascular stolons can sometimes be seen
through the hard translucent test of the stalk, but
in other specimens the stalk is horny and opaque,
and has barnacles, bryozoans and other epibionts
growing on it.

INTERNAL STRUCTURE: Zooids are small, not
more than 4mm in total length, with the almost
spherical thorax larger than the abdomen. Fifteen
fine longitudinal muscle bands radiate from almost
sessile, small, 6-lobed apertures, over the sides of
the thorax and onto the abdomen. Some fine
muscle fibres continue along the posterior
abdominal vascular stolon, Branchial tentacles are
arranged in 3 circles, the largest (about 8) in the
outermost or most posterior circle. Thirty to 40
longish oval stigmata are in each of the 3 rows.
In younger zooids it can be seen that the middle
row of stigmata lengthens first, while stigmata in

the anterior and posterior rows remain short and
almost circular (as they are in the larvae). Stigmata
in the posterior row then lengthen, first at the
dorsal end of the row, while the stigmata in the
anterior row lengthen first at the ventral end of
the row. An area of plain unperforated membrane
exists both anterior and posterior to the perforated
part of the pharynx.

The gut loop is very short, with the small,
rounded stomach about halfway down the
abdomen. A small, oval posterior stomach is
present in the descending limb. The rectum curves
around in the pole of the loop and extends
anteriorly to open at the base of the atrial cavity.
Gonads are crowded in the gut loop, and consist
of about 9 to 16 sometimes relatively large, pear-
shaped testis follicles. These mature only after the
single embryos in the brood pouches of most
zooids in the colony are at advanced stages of
development. Only one egg is present in the brood
pouch at a time. It arrives there when small and,
presumably, is fertilised there.

Tailed larvae are amongst the largest known
in the Ascidiacea, with a larval trunk up to 3.3mm
long. They are present in specimens collected off
Port Hedland in October, and in April and June
from the Dampier Archipelago. Specimens
collected from the Montebello Is in December also
have well formed embryos. Embryos at the
anterior end of the colony are most advanced,
or zooids there have expended brood pouches
while embryos halfway along the head are reaching
maturity. Despite their large size, larvae appar-
ently are released through the neck of the brood
pouch and the atrial aperture. In fact, some larvae
have been found with the tail, folded back on itself,
jammed into the neck of the brood pouch and
the larval trunk deformed and much elongated.
Others have their posterior end jammed into the
neck of the brood pouch and the tail shrivelled
in the process of withdrawal and resorption. Adult
organs — pharynx and gut loop — are confined
to the posterior end of the larval trunk. An ocellus
and an otolith are in the cerebral vesicle, and 3
rows of small circular stigmata are present.
Anteriorly the larval trunk is pointed, with the
openings of the two long, invaginated tubes of
the adhesive organs, one above the other in the
anterior mid-line and a large flat, triangular
epidermal ampulla on each side, Large bladder
cells are packed in the larval test making it firm.

The thin invaginated tubes of the adhesive
organs extend back through the larval trunk to
the oozooid. As the trunk lengthens and narrows
and its posterior end begins to press out into the
neck of the brood pouch, the blind ends of the

98 MEMOIRS OF THE QUEENSLAND MUSEUM

tubes move anteriorly, the tubes become shorter
and wider, Eventually the proximal ends of the
tubes (around the openings) evert slightly from
the anterior end of the larva as cylindrical
projections between the triangular epidermal
ampullae. Subsequently the blind ends of the tubes
evert and project up into the cylindrical openings
at the anterior end of the larval trunk.

These large larvae are unlikely to have a free
swimming phase since the tail is resorbed before
their release from the parent colony. Presumably,
following their release they settle down near the
parent.

Remarks: Larvae of this glassy, transparent,
and possibly indigenous species are remarkable.
The adhesive organs resemble those of Pycnoc-
lavellidae and Euherdmania, but in the present
species the long tubes have not been found
completely everted before settlement. However, no
other characters suggest a close phylogenetic
relationship. Further, many of the characters of
S. mjobergi especially the single, large larva,
position of the brood pouch, body musculature,
3 rows of stigmata, size of the abdomen and course
of the gut are characters shared with other species
of Sigillina.

Thus, until more evidence becomes available,
the species must be considered a member of
Sigillina in which larval adhesive organs have
diverged markedly from those known in other
species of the genus.

Although stalks are absent, Hartmeyer’s (1919)
description agrees with the recently recorded
material, including the unusual pattern of
development of the branchial stigmata. Stalks of
this species differ from those of others in the genus,
which are invariably thick and fleshy rather than
narrow and leathery.

Sigillina nigra (Herdman, 1899)
(Fig. 33)
Polyclinum nigrum Herdman, 1899, p, 84.

DisTRIBUTION

New Recorps: New South Wales (Bateman’s Bay,
AM Y2208)

Previousty Recorpep; New South Wales (Port
Jackson, AM U33 Polyclinum nigrum ident. Herdman,
Herdman 1899).

DESCRIPTION

EXTERNAL APPEARANCE: The newly recorded
colony from Bateman’s Bay is robust, forming a
smooth, flat sheet, up to 2cm thick, completely
investing a large specimen of Herdmania momus,
In preservative the surface layer of test is purple
fading to a cloudy, white translucence toward the

base. The purple is contained in spherical, fusiform
and dendritic cells. The colony from Port Jackson
is lumpy and potato-shaped, with clouds of black-
blue pigment in the surface test (after 8 decades
in alcohol preservative).

INTERNAL STRUCTURE: Zooids open separately
onto the surface of the colony, and are 6mm long
when moderately contracted, with the thorax from
one-third to one-half of the total length. Thoracic
muscles are strong, with about 16 longitudinal
bands down each side, continuing along each side
of the abdomen. They converge into a pointed
projection on each side of the posterior end of
the abdomen. There are 3 rows of about 20 long,
thin stigmata. The stomach is smooth. A short
duodenal area and an oval posterior stomach
occur in the descending limb of the gut loop. The
testis follicles are relatively large and a group of
one large and 3 or 4 small oocytes lie in the gut
loop. The vas deferens is conspicuous and filled
with sperm in both the newly recorded specimens,
collected in November and September respec-
tively. Each has one large embryo and 2 small,
non-fertile ova in a brood pouch attached to the
postero-dorsal corner of the thorax and bent up
against its dorsal border.

The larval trunk is 2mm long and almost
spherical. The tail is wound only halfway around
it. Larvae are retained in the brood pouch for
a long time — being still there when the tail is
withdrawn into the haemocoel and resorbed and
when the adult organs are well developed. The
oozooid is restricted to the posterior two-thirds
of the larval trunk, which is separated from the
adhesive apparatus contained in the anterior third
by a waist-like constriction. However the test
maintains the almost spherical shape of the trunk
and is not constricted at this point, Past the waist,
the larval ectoderm flares out around the 2 very
long, narrow, vertical bands of adhesive cells
depressed into the larval epidermis along the
anterior mid-line. Most, but not all, specimens
have a third, short, patch of adhesive cells,
similarly depressed into the epidermis, between
the 2 long bands. The whole of the anterior part
of the larval trunk (with the adhesive organs) is
surrounded by a band (4 or 5 deep) of fine, straight,
slightly diverging, spikey tentacle-like projections
that arise from the larval ectoderm just where it
begins to flare. These continue through the thick
larval test to its outer surface, Also, about 7 short,
rather irregular ectodermal ampullae on each side
project from around the waist (behind the base
of the band of tentacle-like spikes). However, these
are not always present — a number of well
advanced larvae were found without any ectod-

THE AUSTRALIAN ASCIDIACEA 2 99

Fic, 33, Sigillina nigra: a,b, zooids (AM Y2208, holotype AM U33): e.d. larva (AM Y2204). Scales: a,b. 1mm;

c,d, 0.5mm,

ermal ampullae. As in the larvae of §. fantasiana
and S. digitata, the endostyle of the oozooid is
vertical. There is dark pigment in the larval
haemocoel, but not in the test.

Remarks: The species obviously is related to
S. fantasiana, being distinguished from it only by
its larger and more robust colony and zovids, and
especially by its much larger larvae and the absence
of the regular paired ectodermal ampullae found
in S. fanrasiana. Clearly these large, viviparous
larvae, probably without a free-swimming phase.
would limit gene flow and contribute to isolation
between New South Wales and southern Austral-
ian populations,

Sigillina digitaia (Millar, 1962) from South
Africa has a similar though even larger (4 to4,5mm
long) larval trunk than the present species (see
Millar 1964). Further, the anterior end of the trunk
has a similar arrangement of adhesive organs and

ectodermal ampullae as S. nigra, although the
ectodermal ampullae are longer in the South
Atricun species. Long ectodermal spikes found in
both S. nigra and S. fantasiana are not recorded
for the African species. However, the larvae of
S.. digitata are so large it is possible they were
examined without staining and these processes
may have been overlooked,

Millar (1964) speculates that the large embryo
is contained in an expanded atrial cavity.
However, in his specimen the brood pouch
expands from the posterior end of the thorax, as
in S. figra, causing the thorax to be tilted at right
angles to its normal orientation (see Millar 1964,
p. 164).

Sigillina nigra and §. faniasiana are the only
species in this genus to have thin vascular stolons
on which muscle fibres have not been detected.
It is significant that the thick (5 to 7em) colonies

100

of S. digitata have zooids with conspicuous long
vascular stolons with muscle fibres on them as
in other species of Sigillina.

Millar (1964) observed similarities between the
larvae of Hypodistoma vastum and H. deerratum,
and S. fantasiana. Larvae of the present species
differ from S. fantasiana only in their larger size.
They differ from those of Hypodistoma in having
the adhesive apparatus separated from the
posterior end of the larval trunk by a waist rather
than being on a frontal plate connected to the
posterior 0ozooid by a ventral stalk; and in having
a band of spike-like, anterior ectodermal processes
rather than a single ring of long, digitiform
processes around the adhesive organs.

Herdman (1899) in his original description of
the present species remarked on the long, narrow
stigmata and the gonads in the gut loop (albeit
spilling out behind it).

Sigillina signifera (Sluiter, 1909)
(Fig. 34. Plate 8c,d)
Polycitor signiferus Slutter, 1909, p. 5.
Sycozoa sedens Sluiter, 1909, p. 34.
Eudistoma viridis Tokioka, 1955b, p, 49.
Eudistoma viride: Tokioka, 1967a, p. 122. Millar, 1975,
p. 220. Not Nishikawa, 1984, p. 118.
DisTRIBU TION

New Recorns: Western Australia (Rowley Shoals,
WAM 999.83). Queensland (Swain Reefs, QM G2805-
6 GH2810 GH2688 GH3805; Lizard 1., QM G&595
G11902-4 G12739 GH322 GH3827 GH4096- 100
GH4946; MacGillivray’s Reef, QM GH4091; Cape
Flattery, QM G1I1905; Britomart Reef, QM GH278).
Philippines (QM G12755 GH411 GH451).

Previousty Recorprp: Palau Is (Tokioka 1955b,
1967a). Indonesia (ZMA TU808.1 lectotype Polpcitor
signiferus Sluiter 1909),

The species is common at shallow, sub-tidal depths
in the tropical western Pacific. It is found amongst
coralline algae and other weeds on hard substrates on
undersides or vertical surfaces near reef edges and on
the reef slope from just below low tide level down to
5m, It flourishes on the walls of channels and other
locations where the current flow is fast, and where the
flat, compact upper surface created by the tightly packed
lobes of the colonies is advantageous.

DEscRIPTION

EXTERNAL APPEARANCE; Colonies appear as
transparent bluish-green or greenish-black mats,
up to 1.5cm thick, covering extensive areas. Closer
examination shows these mats consist of tightly
packed, separate cushion-, wedge- or mushroom-
shaped, flat-topped lobes, tapering to the base
which sometimes has root-like projections that
help to anchor the colony. Lobes are either
attached separately to the substrate or to common

MEMOIRS OF THE QUEENSLAND MUSEUM

basal test. They vary in diameter from about 0.5cm
to 3cm. Some of the more extensive plates are
attached to the substrate only here and there,
where the basal test grows down to form a short,
irregular attachment process. Colonies are usually
readily dislodged. Zooids are not crowded and
can be seen opening onto the flat upper surface.
The test is pale and transparent in living colonies
while zooids themselves are often dark blackish-
blue to bright green. Zooids become blackish-
green in preservative. Green cells are concentrated
anteriorly, especially in a ring around the base
of the branchial siphon and in 2 symmetrical arcs,
one on each side, curving down the body wall
from the intersiphonal space, and in longitudinal
lines on the abdomen and posterior abdominal
process where they appear to be associated with
the muscles. Possibly contraction of the muscles
concentrates these pigment particles making them
appear directly associated with the muscles. There
also are some brownish-yellow and minute green
pigment particles in the test of preserved
specimens.

INTERNAL StRucTURE: The thorax and abdo-
men together are 3 to Smm long when contracted.
In addition there is a broad posterior abdominal
vascular process onto which the strong longitud-
inal muscles of the body wall extend to terminate
abruptly at its posterior end, just before it divides
into 2 or 3 short, terminal branches. About 25
longitudinal muscles are on the thorax. About 30
stigmata are in the second and third rows, with
more in the first row, which inclines anteriorly
along each side of the mid-dorsal line as in
Eudistoma. Fairly extensive unperforated areas
are both anterior and posterior to the stigmata.

The gut loop is short, the abdomen being only
about the same length as the thorax. The stomach
is spherical and smooth, about halfway down the
abdomen. There is also a small posterior stomach
before the tube expands into the rectum in the
pole of the gut loop. Gonads, in the loop of the
gut, consist of a conspicuous group of male
follicles and an inconspicuous ovary. A large,
tailed embryo is in the brood pouch constricted
off from the postero-dorsal corner of the thorax
in specimens collected in April (QM G11904), late
June (QM GH4096) and December (QM GH4946)
from Lizard I., and in August (QM G11805) from
Cape Flattery. Specimens from the Swain Reefs
had tailed embryos in July (QM GH2810) and
in January (QM GH2806).

Larvae are large, with a larval trunk about
3.3mm long and a tail about the same length. Dark
pigment particles occur in the larval test and an
ocellus and otolith in the cerebral vesicle.

THE AUSTRALIAN ASCIDIACEA 2 101

Fic. 34, Sigillina wgnifera: ayb, colonies (QM GIL903 GH4096); ¢, contracted vooid with brood pouch (QM
G8595). d. extended zooid (QM GH4099); e thorax showing colour pattern (lectatype ZMA TU&08.1): £.
larva (QM G8595). Scales: a, Smm; b, [em: c-e, Imm: f 0.5mm,

Two large adhesive organs are in the mid-line at
the anterior end of the body. They consist of a
long narrow strip of secretory cells that arise from
the base of narrow depressions. and which, when
the larva is mature are produced forwards on short

stalks as in §. grandissima n.sp, Three large,

forward-projecting, balloon-like ectodermal
ampullae develop from each side of the trunk just
postenor to the base of the adhesive organs.
Remarks: Although the species has all of the
characteristics of the genus well expressed, certain
aspects of its morphology separate it from other
species. These are the unique, flat-topped lobes,
sometimes small and containing relatively few
zooids; zaoid openings an the flat upper surface;
the dark colour of the zooids: and the relatively
large numbers of stigmata in each row. The large
larvae resemble those in the cyanea group, and
in particular S. awszralis, which has 2 long adhesive
organs and similar ectodermal ampullae to those
in the present species. Zooids of this species also
resemble those of S. cyanea and S. australis in
lacking transverse muscles on the thorax.

The lectotype (ZMA TUS08.1) still retains the
concentrations of dark pigment cells illustrated
by Sluiter (1909, pl. 1. fig. 2). These occur in many
of the living as well as lhe preserved specimens.

Colonies of the present species resemble those
of some Eudistuma. However. Euclistona have
more and smaller zooids than the present species,
and never have a brood pouch nora long posterior
abdominal stolon, Audistama viride: Nishikawa.
1984 from the western Pacflic with dark green
test and ‘roundish or flat and investing colonies’
(Nishikawa L984, p. 118), and only occasionally
with a posterior abdominal stolon, are unlikely
to be this species, which never has either dark
green test or flat colonies.

Genus Polydistoma n.gen.

Type species: Polvdistoma fungiforme n.sp.

Zooids of this genus haye 5 rows. of stigmata,
open by a long, posteriorly directed atrial siphon
onto the upper surface of the zooid-bearing part
ofthe colony while the branchial apertures all open

102

onto the under surface, and have a long posterior
abdominal process that extends into the basal test
or stalk of the colony. Fine longitudinal muscles
are present on the thorax and these continue onto
the abdomen and posterior abdominal process.
There are 3 circles of branchial tentacles. The
stomach is small, with a smooth surface, and the
gut loop is short and horizontal.

The method of vegetative replication is not
known, although in one species new vegetative
zooids are seen being added to the system at the
top of the stalk as in Sigillina. The assignation
of the genus to the family Holozoidae is indicated
by its small zooids, short gut loop, arrangement
of branchial tentacles, long and conspicuous
vascular process, and general resemblance to
Hypodistoma. Further data on the method of
replication is needed to confirm this affinity.

Embryos are in the available colonies of one
of the species only, viz. Polydistoma fungiforme
n.sp. They are large and probably rupture directly
from the abdomen to incubate in the test as they
do in Hypodistoma (see discussion on phylogeny
of Holozoidae, above). The zooids of Hypodis-
toma are similar with small and horizontal gut
loops, and long, posteriorly directed atrial siphons
(although these open into common cloacal spaces
rather than directly to the exterior as they do in
the present genus). Polydistoma also differs from
Hypodistoma in its posterior abdominal process
which does not appear to have a septum, and its
5 rather than 3 rows of stigmata.

There are two recognised species in this genus,
both from the southern half of western Australia.
They differ from one another in the shape of the
colony and in the number of stigmata in the
branchial sac.

Polydistoma fungiforme n.sp.
(Fig. 35)

DISTRIBUTION

Tyrer Locauiry: Western Australia (about 27km W
of Cliff Head, Dongara, 29° 30’S 114°41.3’E, to 29°31.7'S
114°42’E, 44m, MV Sprightly 17.2.76, pipe dredge,
holotype WAM 881.83; about 26km SW of Dongara,
29°23’S 114°42’E to 29°24’S 114°42’E, 33m, 17.2.76,
paratypes WAM 880.83 QM GH2///).

DESCRIPTION

ExTERNAL APPEARANCE: The colony consists
of an irregularly branched cylindrical stalk (about
2cm in diameter) with each of the 3 to 6 branches
terminating in a zooid-bearing saucer- to trumpet-
shaped expansion or frond from 3 to 10cm in
diameter. The fronds are thinner around their
outer circumference than in the centre, where the
under surface tapers to the stalk. Each frond is

MEMOIRS OF THE QUEENSLAND MUSEUM

concave on its upper (free) surface. There is no
indication of how the colony is fixed — there is
no basal stalk and all the terminal branches have
zooid-bearing terminal expansions, The long
posteriorly projecting atrial siphons open onto the
upper concave surface and the branchial apertures
are on the under surface. The concavity is
homologous with a cloacal cavity. Zooids are
evenly spaced in the terminal fronds, about 2mm
apart. Stalks contain long, parallel vascular
processes. Smaller zooids are in the centre where
the new replicates are moving up into the frond.
Larger and older zooids are toward the outer
margin,

In preservative colonies are all cream-coloured
with orange pigment particles around the bran-
chial apertures. Their living colour is not known,
The test is firm and translucent,

INTERNAL STRUCTURE: Zooids are about 3mm
long. The thorax is longer than the abdomen, the
gut loop being horizontally oriented behind the
thorax. The 6-lobed branchial aperture is on a
short terminal siphon. The atrial aperture is on
a long, narrow, posteriorly directed siphon from
the postero-dorsal corner of the thorax. The atrial
siphons of smaller zooids in the central (thickest)
part of the colony are long (up to 4 times the
length of the zooid). About 30 branchial tentacles
lie in 3 circles at the base of the branchial siphon,
the 16 longest being in the posterior circle. Ten
fine longitudinal muscle bands on the thorax
extend from the branchial siphon and onto the
abdomen — where they are inconspicuous.
Longitudinal muscle bands also extend along the
atrial siphon, including a few from the branchial
to the atrial aperture along the dorsal border of
the body. The neural gland and ganglion are close
together at the anterior end of the body. The
opening of the neural gland is a curved slit,
obliquely oriented, and directed anteriorly and to
the left. It has a conspicuous tongue-like flap
projecting posteriorly from the right border of the
slit. Dorsal languets are rather short, triangular
expansions of the transverse vessels where they
cross the dorsal mid-line. There are 5 rows each
of 15 long, rectangular stigmata, but no paras-
tigmatic vessels.

The oesophagus curves toward the ventral side
of the zooid, opening into a small, smooth,
spherical stomach with an extremely short suture
line. The stomach lies horizontally about halfway
across the posterior end of the thorax. A fairly
long duodenal area extends posteriorly from the
stomach and curves ventrally before narrowing
to a long mid-intestine that forms the pole of the
gut loop. The mid-intestine has a posterior

THE AUSTRALIAN ASCIDIACEA 2

103

Fic. 35, Polydistoma fungiforme n.gen. n.sp. (holotype WAM 881.83): a, colony; b, zooid; ¢, diagram showing
position of zooids in colony. Scales; a, 2cm; b, 1mm,

stomach expansion about halfway along its length.
The rectum curves up to extend horizontally across
the posterior end of the thorax, sometimes a little
to the left. The distal portion of the rectum opens
at the base of the atrial siphon in a two-lipped
anus, or occasionally it is found curved over into
the proximal part of the siphon. The vascular
process is fine and originates from the left side
of the gut loop. It has a rounded terminal ampulla.
These processes are about Imm long in zooids
from the periphery of the frond, but they are long,
extending parallel to one another down into the
stalk in smaller zooids in the centre.

Gonads were not detected in any of the
specimens. Large embryos (about 2mm long) are
posterior to the abdomen, probably having

ruptured from the side of the gut loop. Although
the tail is differentiated in some, no other structure
is discernible.

REMARKS: Polydistoma longitube does not have
a concavity or other cloacal homologue and,
although closely related to the present species, it
has a vastly different colony structure. The present
species appears unique, and its morphology is
striking. Although there is no record of its
appearance when living, it is possibly beautiful,
with translucent palm-like fronds, in which the
zooids are embedded. There is no sign of its point
of attachment in the one available colony, but
it is not impossible that has broken free it is
not likely to be planktonic.

104 MEMOIRS OF THE QUEENSLAND MUSEUM

Polydistoma longitube Kott, 1957 DESCRIPTION
(Fig. 36) EXTERNAL APPEARANCE: Only the holotype
Polycitor longitubis Kott, 1957a, p. 80. colony has so far been collected. It is a fleshy,
circular cushion, 2cm thick and 6cm in diameter.

DisTRIBUTION ete
New Recorpbs: none. However, the colony appears flattened, and in life

Previous._y Recorpep: Western Australia(? between it could have been upright, possibly top-shaped.
Cockburn Sound and Albany — AM Y802 Kott 1957a). The centre is firm, gelatinous, zooid-free, and has

iy

Fic. 36, Polydistoma longitube n.gen. (holotype AM 802): a, colony; b, zooid; ¢, diagram showing position of
zooids in colony and vascular stolons reaching down into stalk. Scales: a, Icm; b, 0.5mm.

THE AUSTRALIAN ASCIDIACEA 2

the vascular processes of zooids irregularly
seattered through it. Zooids are in the surface layer
of test in areas representing about three-quarters
of the upper surface of the flaitened cushion.
Branchial apertures of zooids around the
periphery open into a depression just inside the
margin of the upper surface, and their long atrial
siphons sometimes extend a considerable distance
through the test to open on the sides of the cushion,
Zooids are also in rather, thin, irregular flaps of
test that seem to overgrow the surface of the colony
to form pockets. The branchial apertures of the
zooids in these flaps open on the under surface
of the flap into the space it encloses against the
surface of the remainder of the colony. The long
atrial siphons open on the outer surface of the
flaps which develop from areund the periphery
of the colony and grow toward the centre, as well
ay growing over toward the periphery froin the
centre,

INTERNAL STRUCTURE, Zooids are only about
2mm long, lhe thorax is longer than the abdomen
which is folded in tightly behind the thorax, The
long atrial siphon from the postero-dorsal part
of the thorax is up to Jem long. however. About
10 fine longitudinal museles oceur on the thorax.
and some extend along the dorsal border of the
thorax between the branchial and atrial siphons.
There are 6 branchial lobes, but none were detected
on the tip of the atrial siphon. Twenty stigmate
vecur in each of 3 rows in the branchial sac,
although these were difficult to count, There are
no parastigmatic vessels,

The gut is rather voluminous, with a smooth
and almost spherical stomach, a long duodenal
area, and a long mid-intestine with a pear-shaped
posterior stomach about halfway along its length,
The rectum curves up against the lett side of the
branchial wall before turning back abruptly so
that its distal end ts in the base of the atrial siphon.
A circle of about 12 pear-shaped male follicles
lie in the gut loop. No ovary was detected.

A long vascular process extends from the right
side of the posterior end of the abdomen. and
it has a few fine muscle fibres on it,

Remarks: Despite the similarity of its zooids
jo those of PL firgiforme, the present species
appears distinct. Polydistoma fungiforme has
relatively narrow cylindrical stalks with circular
2ooid-bearing terminal fronds that contrast with
the massive central test and thin irregular flaps
of zooid-bearing test of the present species.

Polveitor torosus Sluiter, 1909 has a colony that
resembles that of (he present species, and a long
atrial siphon from the posteriorend of the thorax

105

However, it bas only 3 rows of stigmata and
belongs in the new genys Exosroma in the
Polyeitordae,

Genus Hypodistoma Tokioka, (967
Type species: Distoma deerrarum Sluiter, 1895,

Colonies are massive, solt and sessile. Zooids
are small, with long, posteriorly projecting atrial
siphons opening into extensive cloacal spaces
which separate a basal or central core of test from
the outer, zovid-bearing layer, Atrial apertures are
6-lobed, The abdomen is relatively short, usually
shorter than the thoraa. Fine longitudinal muscle
bands on the thorax continue onto the long
posterioe abidlominal stolony that extend into the
central core ol test. On the thorax transverse
museles lic beneath the longitudinal ones, There
ure 3 rows of Stigmata. without parastigmatic
vessels,

Ova probably are fertilised in the abdomen,
Sometimes embryos are incubated free in the test
haying detached themselves fromthe abdomen ( //,
vaxtun, FH. ovirahile), or they develop, one at a
time. in a brood pouch attached to the postero-
dorsal corner of the thorax (A. deerratum).

Larvae, known for all except Mf. mirahile, are
large and have an unusual tringe of uniform
tentacle-like processes around the characteristic
adhesive organs. The adhesive organs are
depressed into a frontal plate which is jomed to
the posterior half of the larval trunk by a ventral
stolon,

The similarity between the larvae of this genus
and those of Sigillina may be only apparent.
associated with their lurge size. The adhesive
organs are large and depressed into the ectoderm
in both species. However, in Sigillinag a waist
scparates the anterior adhesive region of the larval
trunk [rom the posterior half with its developing
blastozooid, while in Hppodistoma the adhesive
organs are on a frontal plate that is joined to the
posterior part of the larval trunk by a ventral
ylolon. The spike-like processes that radiate out
through the test from the anterior part of the larval
epidermis in Sigi/lina fantasiana and related
species may be homologues of the ring of tentacte-
like processes thal surround the adhesive organs
in Hypodistoma — but that is not certain. The
presence of 3 rows of stigmata, in Hypoedistana
and Sigillina could be a convergent character, as

2ooids of Polvdistoma n.gen,, With more rows of

stigmata, are otherwise more like the zooids of
Hypadistoma than Sigillina. Hypodistoma also
resembles the new genus Palyeistoma in that
fertilisation is probably at the base of the oviduct,

106

TABLE 4. Summary OF CHARACTERS OF THE SPECIES OF HypopistoMA RECORDED FROM AUSTRALIA

Incubation of
embryos

Larval trunk

Systems

Colony
shape

2Range

‘Biogeographic
description

Species

(length, mm)

around

Australia

MEMOIRS OF THE QUEENSLAND MUSEUM

? separated from abdomen

numerous scattered
cloacal apertures

single terminal

irregular cushion

South Australia

A,te

H. mirabile

in thoracic brood pouch

0.8

flask

Low Is—Abrolhos

WP,tr

H. deerratum

cloacal aperture

\A, indigenous; WP, western Pacific; tr, tropical; te, temperate. 2>Range given anticlockwise around the continent.

the embryos separating from the abdomen and
developing in the test (see discussion on Holo-
zoidae, above).

Hypodistoma vastum: Tokioka, 1967a was
thought a synonym of H. vastum (Millar, 1962).
However, Tokioka’s specimen lacks the large
posterior abdominal stolon, has the long zooids
characteristic of Polycitoridae and is a junior
synonym of Polycitor ianthinus Sluiter, 1909 (see
Millar 1975). It has been assigned to the new genus
Exostoma in the Polycitoridae (see below).

Hypodistoma is represented by 3 species, H.
deeratum from the Philippines to Houtman’s
Abrolhos on the western coast of Australia and
Heron I. on the eastern coast, H. mirabile from
the Great Australian Bight to Western Port
(Victoria), and H. vastum Millar, 1962 from South
Africa (see also Millar 1963b). It appears an Indo-
West Pacific genus, H. vasta and H. mirabile being
temperate representatives.

The species are distinguished from one another
by differences in colony form, by differences in
the size of the larvae, and by differences in
brooding of the embryos — H. vastum and H.
mirabile have embryos incubating in the test,
having separated from the abdomen, while those
of H. deerratum move from the abdomen into
a narrow-necked thoracic brood pouch.

Hypodistoma vastum (Millar, 1962) from South
Africa (see also Millar 1963b, 1964) resembles H.
deerratum, and its relationship with the latter
species is discussed below (see H. deerratum).

Hypodistoma deerratum (Sluiter, 1895)
(Fig. 37. Plate 8e)
Distoma deerrata Sluiter, 1895, p. 167.
Sigillina deerrata: Hastings, 1931, p. 87.
Altapozoa deerrata: Kott, 1967, p. 185; 1972e, p. 44.
Hypodistoma deerrata: Millar, 1975, p. 215.
Polycitor coalitus Sluiter, 1909, p. 23.
Sigillina (Polycitor) coalita: Michaelsen, 1930, p. 484.

DistRIBUTION

New Recorps: Western Australia (Port Hedland,
WAM 995.83 997.83; Cape Preston, WAM 791.83;
Montebello Is WAM 789.83 998.83; Dampier Archipe-
lago, WAM 996.83; Houtman’s Abrolhos, WAM 788.83
790.83). Queensland (Heron I., QM GH1383; Abbot
Point, QM GH706 GH729; Townsville, QM G8590;
Cairns, QM GH4095; Lizard I., QM G10153, AM Y2134;
Stanley Reef, QM GH2351; Cape Tribulation, QM
GH781, AM Y2140; Cape Kimberley, QM GH4092;
Princess Charlotte Bay, QM GH4094; Bathurst Head,
QM GH4093; Thursday I., QM G9809-11 GH301;
Murray I., QM GH301). Northern Territory (Darwin,
QM GH 4225).

Previous_y RecorRDED: Queensland (Low Is —
Hastings 1931; Thursday I., Torres Strait — Sluiter

THE AUSTRALIAN ASCIDIACEA 2

er

ae ww =
he:
ae

—— — ae
Ss
72

a=

iY

107

Fic, 37, Hypodistoma deerratum: a, colony (QM GH2354); b, zooid (QM GI10153); ¢, larva (WAM 791.83).

Scales: a, lcm; b, Imm; ¢, 0.1mm.

1895). Northern Territory (Gulf of Carpentaria — Kott
1966, 1972e). Philippines (Millar 1975).

The species has been recorded down to 80m. It is
tropical, extending south only to Houtman’s Abrolhos
and Heron I. — the southern extent of the coralline
regions on the western and eastern coasts of Australia,
respectively.

Description

EXTERNAL APPEARANCE: Colonies are large (up
to about [5Scm high and 8cm diameter) upright
and more or less flask-shaped, narrowing to a firm
base and often narrowing terminally as well. A
large, often terminal, cloacal aperture, surrounded
by thin zooid-free test, has a smooth rim and
protrudes from the upper surface. The firm basal
test continues up into the centre of the colony
forming a firm core. The outer layer of zooid-
bearing test, which often continues above the
central test core to enclose a central cavity in the
upper part of the colony, is soft, irregular and
complex, being divided by deep furrows that
separate the surface into lobes and ridges. It is
penetrated by large cloacal spaces that partially

separate the zooid-bearing layer from the central
core of firm test. Zooids are crowded in circular
groups beneath the outer surface of the test as
well as in the base of the furrows and clefts in
the surface. Branchial apertures open to the
surface where the zooids are located. Atrial
apertures are on long, tubular siphons that open
into the large cloacal spaces behind the zooids.
The circular areas containing the zooids often
protrude as shallow mounds from the surface of
the colony.

In preservative colonies are rather dirty beige,
pink or purple, sometimes with brown flecks.
Living colonies have been described as ‘grey with
yellow’ and ‘purple variegated’.

INTERNAL StRucTURE: Zooids are small, about
3mm long, excluding the siphons. The branchial
siphon is sometimes as long as the rest of the zooid.
The atrial siphon, projecting posteriorly from the
posterior end of the dorsal border of the thorax,
is at least as long as the branchial siphon, but
often it is longer. Both apertures have 6 small
lobes around their rims. A long, narrow posterior

108

abdominal stolon extends trom the posterior end
of the shdomen into the central lest core of the
colony. The thorax has circular muscle fibres
forming wn almost continuols coat around its
posterior two-thirds, The siphons are also
surrounded with circular muscles, Longitudinal
muscle bands from each siphon extend ulong the
length of the abdomen. About 6 tine muscle fibres
are on the posterior abdominal stolon,

The branchial sac has 3 rows each ol 10 Jong
stigmata. A wide expanse of unperforated
pharyngeal wall lies anterior to the stigmata and
another less wide is at the posterior end of the
pharynx. The abdomen is shorter than the thorax
and the gut loop tight and rather narrow. The
small, spherical stomach is in the posterior third
of the descending loop, ‘Thus, the oesophagus is
Jonger than it usually is in Sigilina. There is a
small, oval, posterior stomuch in the descending
limb before the gut expands into the rectum,
Gonads, in the abdomen. consist of a small group
of testis follicles, and usually one large ovum.
Embryos develop, one at a time, in the braod
pouch separated trom the postero-dorsal corner
of the thorax by a narrow neck. Tailed larvae
are in the brood pouch in some specimeny Laken
from Cape Preston in December (WAM 791.83),
fram Lizard Il, in November (QM GI01IS53), trom
off Cairns in February (QM G4095), and from
off Cape Tribulation (QM GH781) and Cape
Kimberley (QM GH4092) in September.

The larval trunk is more or less spherical, 0.8mm
in diameter The tail is wound three-quarters of
the way around the trunk, Most of the Jarval trunk
is occupied by the developing adult organs, vic.
the pharynx with its 3 rows of stigmata and the
developing gut loop, The three adhesive organs
are in the median vertical line at the anterior end
of the trunk. hey are carried on a stalked frontal
plate that extends dorsally from the ventral part
of the anterior end of the oozeoid, Each consists
of a central column of adhesive cells rising from
the base of a concavity in the epidermis of the
frontal plate. There isa large ocellus and an otolith
in the cerebral vesicle. A fringe of evenly spaced,
parallel, forward-projecting, fine. tentacle-like
projections of uniform length encircle the frontal
plate reaching from the base of the adhesive organs
to the surface of the test,

Remarks; The South Atrican Hypadistama

vastuor (Millar, 1962) is distinguished [rom the

present species mainly by its larger larva (the larval
trunk being 1.9mm long). the embryo apparently
separates from the abdomen and develops tree in
the test rather than in a brood pouch attached
to the thorax (Millar 19636), Hypodistoma

MEMOIRS OF THE QUEENSLAND MUSEUM

sairabie is distinguished by its cushion-like rather
than upright colonies, the longitudinal rulges on
its surface. its longer (7mm) zooids. and (like 4,
vastum) the absence ol a thoracic brood pouch.

Hypodistoma mirablle (Kott, 1972)
(Fig, 38. Plate 8! h)
Atapazva mirabilis Kou. 1972b. p. 16%: 1976, p. 456,

Dist RHUr roy

New Rereorns South Australia (Great Australian
Bight, OM GH2379 GH4198), Victoria (Bass Strait, MV
H756),

Previausiy Rreerprm South Australia (Great
Australian Bight — Koll 1972b), Victoria ( Western Part

MY FS538/8 Kott (974).

The species has been taken at depths from 7 to én.
often in caves where there is strong water movement.

DESCRIPTION

Exieenat AprearAnce: Colonies are large,
irregular, Meshy masses, with dark ridges along
the surface and deep furrows between them.
Furrows sometimes continue into cavities, These
are pockets in the colony 4 continuation of
the outer surface which has become complex
owing to its folding. Branchial apertures of zooids
open all over the outer surface and into these
pockets. Common cloacal apertures are large and
conspicuous and several eccur along the ridges.
Common cloacal cavities are ben¢ath the rather
thin layers of zooid-bearing test in the furrows
and ridges of the outer surface, and lining the
pockets in the colony. The whole colony is
traversed by spaces, cither pockets in the test or
common cloacal cavities.

Living colonies ure pinkish beige with dirk
brown along the ridges which persists in the
preserved nyaterial,

INTERNAL SrruevuURE, Zooids are only about
3mni long, with the abdomen only about half the
lengih of the thorax, The branchial aperture is
on a short siphon. The atrial siphon is. long,
projecting posteriorly from the posterior half of
the dorsal border of the thorax Lo open inta the
cloacal cavities beneath the Zooid-bearing layer
of test, The rims ol both the branchial and atrial
apertures cach have 6 lobes. Ten fine longitudinal
muscles on the thorax extend alony the abdomen
and jn a band along each side of the posterior
abdominal stolon. A layer of fine transverse
muscles surrounds the posterior two-thirds of the
thorax. Circular museley are around the branchial
siphon and along the length of the atrial siphon.
The branchial sac has 2 long elliptical stigmata
in each of the 3 rows, The unperforated part of
the pharyngeal wall antertor to the stigmuta is
long, occupying almost the whole anterior half

THE AUSTRALIAN ASCIDIACEA 2

of the pharynx. A shorter unperforated area is
at the posterior end.

The gut forms a narrow tight loop, with the
small, smooth stomach about halfway down the
abdomen, and small posterior stomach also in the
descending limb of the gut. The rectum extends
from the pole of the gut loop and curves oyer
into the proximal part of the atrial siphon. Gouads

i

> a

Fig. 38, Aipodistoma nitrahile (QM GH2379): zooid.
Scale, 0.5mm.

109

are present in the gut loop. They are mature in
colonies collected in April from Western Port
(Kott 1976), but not in those from Elliston Bay
collected in May (Kott 1972b), nor the newly
recorded ones from Ward J. collected in April(QM
GH2378), The Victorian material has a large ovum
attached to the side of the gut loop, Larvae are
nat known for this species,

REMARKS. The species, with posteriorly directed
atrial siphon opening into cloacal cavities beneath
the zooid layers, resembles H. deerratum and H.
vasium (from South Africa) although the zooids
are smaller. Hypodisioma vastum has large
embryos developing free in the test, although
Millar (1963b) did not know how they got there.
The large ovum attached to the abdominal loop
in colonies of the present species from Western
Port suggests that, instead of moving up the
oviduct to develop in the brood pouch attached
to the postero-dorsal corner of the thorax, the
ova of this species are fertilised and imitially
incubated at the base of the oviduct. They could
subsequently break away from the zooid to
complete development in the test, as do the single
embryos in the family Didemnidae and possibly
in Polydistama and certain Distaplia.

Genus Distaplia Della Valle, 1881
(nomen conservandum)

Type species: Holozoa cylindrica Lesson, 1830

The genus ts characterised by its relatively short
zooids each with a 6-lobed branchial aperture, and
a wide atrial opening with the upper border
produced into a large anterior lip. Zooids are
arranged regularly in one or more circular, or oval,
ot long radiating, dauble row cloacal systems.
Colonies are fleshy sheets, cushion-like or stalked.
The test often has a spongy consistency. There
always are 4 rows of long stigmata, usually crossed
by a fine parastigmatic vessel. The stigmata in
each row are progressively reduced in length
toward the ventral line, leaving three small
triangles of unperforated pharyngeal wall bounded
by the ventral ends of rows of stigmata and the
endostyle. Pointed dorsal languets are on the
transverse vessels on the left of the dorsal sinus.
The stomach wall is often folded. A posterior
stomach is absent. Often (but not always) a large.
Spherical to oval gastric reservoir is in the gut
loop. The junction between the mid-intestine and
the rectum is always well defined and often has
a distinct rectal valve. Gonads, consisting of a
cluster of Jarge testis follicles and a small group
of ova, are either in the gut loop, or in a narrow-
necked sac projecting from it. A conspicuous

110)

vascular process trom the left side of the pesterior
end of the abdumen extends into the base or contre
of the colony and down into the stalk (when one
is present). Fine musele bands extend obliquely
from the branchial aperture and the intersiphonal
space Lowatd the postero-dorsal corner of the
thorax, They muy sometimes extend onto the
abdomen but are inconspicuous and seldom
detected, Muscle fibres have not been detected on
the vascular process, Dorsal muscles in the
intersiphonal region curve oul around the anterior
atrial lip and extend down euch side of the
aperture, Ova are fertilised, and embryos are
hroaded, ina loop of the distal part af the oviduct
thal projects. into a sac from the postero-dorsal
part of the thorax behind the atrial opening. The
brood pouch hecomes detached trom the zooid
to fie free [A the test. Embryos probably are freed
from the surface of the colony by rupture of the
fest.

Known larvae are all similar. They are large,
With triradially arranged stalked, adhesive organs.
The stalks of the adhesive organs develop large,
rounded ampullary swellings at their base. They
have a protruding axial cone of columnar cells
surrounded by a cup-shaped structure consisting
ol un outer and parietal layer of specialised
ectodermal cells, Each axial cone has a hyaline
cap. the tip of which projects through an aperture
in the larval test. Adhesive organs conform to
those of Distaplia occidentalis Baneralt (see
Cloney 1977), These are supported on @ stolon
from the posterior end of the covooid which
persisty as a vasculat appendage following
metamorphosis, Usually both eellus and tolith
are io the cerebral vesicle. Adult organs, especially
the branchial sac and the gul loop, ure well
developed and the former is especially large,
vecupying about one third of the larval crunk.
Larvae are Unusual in producing small buds fram
epicardial tissue at the junction of the oesophagus
and pharyax (Berrill 1935b), The larval test
contains-crowded bladder cells and ollen pigment
particles that obscure the developing organs. Mast
known species have only one embrvo in each brood
pouch — although a few species (2. ausrrafiensis,
A. muriellansp. and D. violeitan.sp.) have more,
Larvae arc remarkably similar. with short tails.
and large and sometimes almost cigur-shaped
trunks containing vegetatively produced buds
developed {rom the epicardial sacs af the posterior
end of the pharynx,

The epicardial epithelium constitutes the
regenerative tissue (Brien 1948) lor replication in
the adult, Replication occurs in 2 ways, viz, from
numerous vegelative stolons (each contaming a

MEMOIRS OF THE QUEENSLAND MUSEUM

vestige of the left epicardial sac) saluted from the
postenor end of the abdomen, near the vascular
appendage; or from the remains of the anterior
horns of the epicardial sacs that persist in the test
following dissolution of the zooids (Berrill 1935h}.
Replication is prolific, but less so (hanin Speozed,
Species with several systems have randomly
scattered cloacal apertures on the upper surlace
of segsile colonies and all around the zooid-bearing
head of stalked colonies. Divtuplia x\slermulica
Tokioka, 1959 from Japan has a single circular
system in each separate lobe of the colony. In
others with single systems, viz. Distaplia anstra-
liensiy Brewin, 1953, D, vallii Herdman, {886 and
Do emitht Abbott and Trason, 196% trom Cali-
fornia. zooids are arranged in rows along each
side of the ony canals that converge to a terminal
cloacal aperture thus differing from Syeazea
which have log parallel canals that terminate
around the flat, zooid-lree upper surlace,
Distuplia is remarkably homogenous and can
conlidently be regarded as monophyletic. Within
the genus. species parameters are far from
resolved. Differences in the colony from
cushion and extensive sheet-like forms fixed by
a large area ol the base, to stalked beads -- have
been regarded as intraspecific by many authors
(Michaelsen 1930, Tokiokw 19672. Millar (975).
However. in most of the cases referred to by these
authors, associated differences in the zooids have
heen cletected that suggest genetic isolation and
it is probable the colony form is a more reliable
indicator of species identity than formerly though,
ly this study characters used to define a species
are colony form (either sheet-like, sessile cushions
or stalked), position of gonads (cither in the gut
luop or in a sac-like posterior abdomen),
arangement of the vooids (either around, or in
double rows radiating from, the cloacal apertures:
or a combination of both). There are also
interspecific differences in the ratio of longitudinal
thoracic muscles (from the branchial siphons) to
oblique muscles ({rom the ventral mid-line), the
shape of the stomach and its orientation. the
canditian of the stomach wall (either smooth,
papillated, or folded, or with the internal lining
raised into longitudinal ridges or reticulations),
the number of testis follicles, and the number of
embryos in the stalked brood pouch.
Remarkably little intraspecific variation occurs
in the numbers of stigmata per row — rarely more
than 4, and usually lewer, bemg involved, Further
the characteristic number is present in all but the
smallest vegetative zoulds. There are one or 2 more
present On One side of the branchial sac (usually
the Jett) (han the ather, and usually 2 less in the

THE AUSTRALIAN ASCIDIACEA 2 IlI

posterior row than the anterior 3 rows. Previously
reported intraspecilic variations and ranges in the
number of stigmata probably have resulted from
difficulties in counting the stigmata of contracted
thoraces. The major interspecific differences in the
larvae are their size and the development of the
ampullae around the base of the stalked adhesive
organs,

The large, short-tailed larvae brooded for along
time in the parent colony, may not be widely
dispersed. This could be the reason for the
isolation that has resulted in the large numbers
of apparently indigenous species of limited ranges
known from tropical as well as temperate seas.
In addition tothe 12 indigenous Australian species
reported on below, there are 4 indigenous Japanese
species (Tokioka 1963), 3 indigenous South
African species (Millar 1962), 3 indigenous New
Zealand species (Brewin 1956b) and 2 species from
the western Pacific (D. va//ii Herdman. 1884 and
D, mikropnoa Sluiter, 1909),

‘Tropical species are few (D. cuscina nsp., D.
violetta n.sp., D. vallii and D. mikropnoa trom
the Pacific; D. sty/ifera from the Indian Qcean),
The last 3 have wide geographic ranges.

Key to THE Species OF DistTarlia
RECORDED FROM AUSTMALIA

!_ Gonads in a sac posterior to abdomen, ...2
Gonads not in a sac posterior to abdomen. .
fe ee Pe ee re Se ee See ero e a «6
Systems one per stalked head of colony... .
ey Wate oye son eee ...1.D. ausiraliensis
Systems more than one per stalked head of
COIGNY.« ofa vb.ds qr ie treet osariariere 3
3. Stomach with external folds........0....4
Stomach without external folds,....-...-5
CHS alo pago eee Mi setee: D. prolifera asp.

4, Testis follicles short, bunched ...-.,-...- 5
Testes follicles long, parallel... ..
MOida su 2. Yeas voaey. D. violetia asp.

5. Colonies usually stalked; parastigmatic
vessels. usually absent........ D. stylifera
Colonies not stalked; parastigmatic vessels
Pesenll 45 ce /s'a ngs annotate s D, takiaka n.sp.

6. Stomach with external folds.....-....+.. 7
Stomach without external folds..........8

7. Stigmata > 12 per row........... D. dubia
Stigmata not > 12 per row ..,,-,.D. pallida

§. Colonies rope-like ....0. relinaculata n.sp.
Colonies not rope-like...... Latot slat cto iyo

9. Systems with radiating double rows of zooids;
oesophagus constricted distally .........
satan age Oe Wet oerp toe D, muriella nsp,

th

ee ewe ewes

Systems oval or circular: oesophagus not
constricted distally ..............2.-- id

10. Stomach with conspicuous Jongitudinal
ridges internally ......,. D, cuscina tsp.
Stomach without conspicuous Jongitudinal
ridges internally ...... inate vratecrelerveleri lt

11. Thoracic muscles mostly longitudinal... ...
A ee ee ee a D. regina tsp.
Thoracic muscles not mostly longitudinal ..
pated cent Sedat se tentee tele bitate§ 12

(2. Stigmata 22 or more per tow,.,,.,-+,-- 3
Stigmata less than 22 per row....D_ virtelis

13. Larval trunk > 2mm: thoracic muscles
Jongitudinal and oblique.......... Peete

err birk Sel eins eine siptees D. florida asp.
Larval trunk < 2mm; thoracic muscles mostly
ObNgUe . 6. eee eee eee D. racemosa 1.sp.

Species recorded from adjacent areas, but not
recorded from Australia are:

Distaplia capensis Michaelsen, 1934 from South
Africa has similar colonies to D. violetta n.sp,
but its gonads are in the abdomen, Its zoids,
with stomach folds, resemble those of D. pallida
(see also Millar 1962. 1964).

Distaplia durbanensis Millar, 1964 trom South
Africa is unique in having an abdominal brood
pouch and @ transverse atrial opening across
ihe posterior third of the dorsal surface. 1) has
astalked colony and a rounded almost spherical
head. Its stomach has interna! papillations
sometimes arranged in longitudinal lines as in
D. muriella n.sp.. and its gonads are in the gut
loop.

Distaplia mikropnea (Sluiter, 1909) from Indone-
sla, forms a massive colony that distinguishes
it from the stalked D. stylifera, It also has an
anastomosing network of stomach folds rather
than the parallel ones of the Jatter species.

Distaplia skoogi Michaelsen, 1934 (see also Millar
1962) from South Africa, has small cushion-
like colonies with circular systems, Its gonads
are in a posterior abdominal sac. It lacks true
stomach folds, but otherwise is similar to the
South Australian D. rekioka n sp. The cushion-
like. broadly based specimens assigned by Millar
(1975) to D. sivlifera may be this species (see
Millar (975, fig. 17a) or D. vielerra n.sp,

Distaplia sivlifera: Millar, 1975 (part, specimen
21.3.1922 from Toeal) is not correctly assigned.
The position of the rudimentary ovary project-
ing from the abdomen, is not an incipient
posterior abdomen but is normal in juvenile
vegetative zooids, as is the presence of an atrial
siphon, Therefore, this specimen could belong
to a species in which the gonads are contained

MEMOIRS OF THE QUEENSLAND MUSEUM

112

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THE AUSTRALIAN ASCIDIACEA 2

in the gut loop. It resembles the new species
D. racemosa n.sp. from northern Australia but
is distinguished from it by the form of the colony
— Millar’s specimen consisting of separate lobes
with a single system per head. It appears similar
to D. systematica Tokioka, 1958 from Sirahama
(Japan), Millar’s drawing (Millar 1975, fig. 18)
showing the preponderance of transverse
muscles characteristic of the Japanese species,
Distaplia vallii Herdman from the Philippines
has colonies consisting of similar stalked heads,
but it has double row systems.

Distaplia tahihuero Monniot and Monniot, 1987
from Tahiti has colonies closely resembling
those of D. cuscina n.sp. both in form and in
colour — both living and in preservative. Zooids
differ only in the fewer testis follicles — 6 to
8 in D. cuscina and 3 or 4 in the specimen from
Tahiti. This may indicate no more than a
population difference.

Distaplia vallii Herdman, 1886 from the Philip-
pines (not Holozoa vallii: Van Name, 1918 <
D. cuscina n.sp.) has numerous stalked heads
from a common base, each head a single system
with double rows of zooids converging to the
terminal cloacal aperture. The colonies most
resemble those of D. australiensis, but the
gonads of the Philippine specimen are in the
gut loop rather than in a posterior abdominal
sac.

Distaplia australiensis Brewin, 1953
(Fig. 39. Plate 9a)
Distaplia australiensis Brewin, 1953, p.61. Kott 1957a,
p.95; 1975, p..

DistTRIBUTION

New Recorps; South Australia (Spencer Gulf, QM
GH2288; St Vincent Gulf, QM G10126). Tasmania
(d’Entrecasteaux Channel, TM D251] D2021; Huon
Channel, TM D1850). Victoria (Bass Strait, QM
G11871). Queensland (Calliope River, QM GH2158).

Previousty Recorpep: South Australia (Spencer
Gulf — SAM E1993, QM G9259 Kott 1975). Tasmania
(S. Tasmania — AM U384 Brewin 1953, Kott 1957a;
d’Entrecasteaux Channel — Kott 1957a).

The maximum depth at which the species has been
taken is 50m. Most records of this species are from a
relatively small area between Spencer Gulf and the
eastern coast of Tasmania. The record from Gladstone
is anomalous. It either represents an isolated population
of this species, or it indicates inadequate sampling of
a species with a continuous range between tropical and
temperate waters.

DESCRIPTION

EXTERNAL APPEARANCE: Colonies consist of a
number (up to 10) of spherical to conical heads,
up to 1.5cm in diameter, on fleshy cylindrical stalks

113

longer than the head and about half its diameter.
Stalks are joined to one another basally and to
a mat of test. Zooids are arranged in double rows
radiating from a large terminal cloacal aperture
in the centre of the upper surface of the head.
Intervals between the double rows of zooids are
where the cloacal canals extend beneath the
surface test from the terminal cloacal cavity down
the sides of the colony. The sides of the zooids
away from the canals are close to the zooids in
the adjacent row. The test has a spongy
consistency.

Living colomes are blue-grey. In recently
preserved material colonies are greenish-blue, the
test containing inky-blue particles that colour the
preservative, Later this colour is lost and the
colonies are beige.

INTERNAL SrRuctTuRE: Zooids are small, the
thorax and abdomen together being about 4mm
long, and the sac-like posterior abdomen attached
to the right side of the posterior end of the
abdomen is, when the gonads it contains are
mature, only about half that length. About 30 fine
muscle bands are on the thorax, about half
extending obliquely from the endostyle toward the
posterior end of the pharynx. Muscles were not
detected on the abdomen, The dorsal muscles cross
the mid-dorsal line around the top of the atrial
opening where they curve out into the pointed
lip that is produced from the upper border of the
opening. They then pass down along each side
of the opening. These muscles are crossed by
strong bands from the branchial aperture extend-
ing along the centre of the atrial lip; and a few
extend from the borders of the atrial aperture
transversely across the sides of the body. The atrial
opening is asymmetrical, one side of the aperture
exposing more of the branchial sac than the other.
The asymmetry is dependent on the side of the
cloacal canal on which the zooid is located, the
side facing the cloacal canal being the one on which
the branchial sac is exposed. There are 13 stigmata
per row in the 3 anterior rows and [2 in the
posterior rows on the left, and 12 and !1
respectively on the right. A fine parastigmatic
vessel crosses each row of stigmata.

The stomach, about halfway down the abdo-
men, is short on its right side where the
oesophageal opening is located, while the left side
is long and widely curved. The oesophagus bends
ventrally to open into the stomach. The stomach
wall has about 16 narrow ridges in its internal
wall that appear as shallow folds on the surface.
They extend from around the oesophageal opening
to the pyloric end, The mid-intestine opens into
the rectum near the posterior end of the descending

114

Fic. 39, Distdplia australiensis: a, colony (QM GH2288);
b,c, zooids (QM G9259 GH2158); d, larva (QM

GH2158). Scales: a, 5mm; b, 0.5mm; ¢,
0.25mm.

Imm; d

limb of the gut loop. There is a conspicuous gastro-
intestinal reservoir suspended about halfway along
the duct between the stomach and the proximal
part of the intestine. The specimens from
Queensland have about 24 stomach folds.
Gonads are contained in the posterior abdom-
inal sac connected to the right side of the posterior
end of the abdomen by a narrow neck. The testis

MEMOIRS OF THE QUEENSLAND MUSEUM

consists of a barrel-shaped mass of 5 to 6 long
follicles joined to the vas deferens at the anterior
end. A clump of about 5 ova of various sizes are
at the posterior end of the testis. Brewin (1953)
recorded specimens collected in September with
a single early embryo developing in the brood
pouch attached by a long narrow neck to the
postero-dorsal part of the thorax just behind the
atrial opening. Specimens collected in April (QM
G11871), July (TM D1850) and September (QM
G10128) had no embryos. Previously recorded
specimens from Spencer Gulf collected in
September (Kott 1975) have a single early embryo
in each brood pouch, but no tailed larvae.
Specimens taken in May from Spencer Gulf (QM
GH3288) had up to 3 developing embryos, one
at an advanced stage, in the brood pouch.
Specimens from the Calliope River collected in
October have the characteristic long-necked brood
pouches and each contains 3 to 5 developing
embryos. The evidence suggests breeding periods
in spring and autumn.

The larva has a long trunk (1.5mm) but the
tail reaches only halfway along it. There is an
ocellus and otolith, The stout stalks of the adhesive
organs expand basally.

Remarks: Re-examination of specimens from
Upper Spencer Gulf and d’Entrecasteaux Channel
(Brewin 1953 and Kott 1957a, 1975) revealed the
numbers of stigmata in each row are as reported
above. Further, the numbers of thoracic muscles
and stomach folds reported by Kott (1975) for
the South Australian material are too low, the
actual numbers being in the vicinity of 30 and
16 respectively. The parastigmatic vessels, which
were overlooked by Brewin (1953), are always
present.

Distaplia australiensis is distinguished from all
other Australian species by its long, double rows
of zooids radiating from a single, terminal cloacal
opening comprising a single system in each stalked
head. Like D. smithi Abbott and Trason, 1968
from California, it has a number of stalked heads
joined basally to common test. The Australian
species has a longitudinally folded stomach in
contrast with the areolated stomach surface in the
California species.

Distaplia vallii Herdman, 1886, from the
Philippines, also has stalked heads arising from
a common base, each head consisting of a single
system, with double rows of zooids radiating from
a terminal common cloaca. It is distinguished from
D. australiensis principally by the absence of a
posterior abdomen. The Atlantic species Distaplia
bursata (Van Name, 1921), which Michaelsen
(1930) thought to be a synonym of D. stylifera,

THE AUSTRALIAN ASCIDIACEA 2

has a colony and other characters more closely
resembling the present species, although it has
shorter stalks and flatter heads.

The specimen from the Calliope River, Glad-
stone differs from those from southern Australian
locations in the greater number of folds on the
stomach. On information available the separation
of the Gladstone population from the southern
Australian ones is not justified although the record
from such a widely separated location is surprising.

Distaplia cuscina n.sp.
(Fig. 40)
Holozoa vallii: Van Name, 1918, p. 140.
Distaplia vallii: Millar, 1975, p. 227. Kott, 1981, p. 149,

DisTRIBUTION

Type Locauity: Queensland (Capricorn Group,
Wistari Reef, rubble fauna, low tide, coll. P. Kott 17.6.85,
holotype QM GH4381, paratypes QM GH4124).

FurtHer Recorps: Queensland (Capricorn Group,
QM GH4120-3 GH4125-6 GH4200).

Previous._y Recorpep; Philippines (Van Name 1918,
Millar 1975). Fiji (Kott 1981).

Fijian and Australian records are from intertidal
locations. Records from the Philippines are from depths
to 40m.

DESCRIPTION

EXTERNAL APPEARANCE: Colonies are soft
cushions not more than 5mm thick. Zooids,
opening onto the upper surface of the colony, are
arranged in circular systems around central cloacal
apertures. Borders of the cloacal apertures do not
protrude from the surface of the colony.

The test is soft in smaller colonies, but spongy
in larger ones. Living colonies are cloudy rose,
soft lilac, having a mixture of dark purple,
lavender and white pigment cells in the test. Zooids
are white. Freshly preserved colonies, with indigo
pigments cells in the test, are slate-blue; subse-
quently they become light green fading to beige.

INTERNAL Structure: Zooids are small,
usually less than 2mm long, excluding the
relatively short, fine vascular appendage. About
20 fine thoracic muscles extend from the endostyle
and branchial siphon toward the postero-dorsal
corner of the body. Dorsal muscles curve out into
the very long atrial tongue before extending
posteriorly along each side of the atrial aperture.
Also longitudinal muscles in the atrial tongue cross
these dorsal muscles. The tip of the atrial tongue
has 3 short lobes that insert into the test around
the cloacal aperture. Branchial lobes are only
shallow. The usual 4 rows of stigmata are crossed
by afine, often inconspicuous parastigmatic vessel.
Some slight variation occurs in the number of
stigmata, e.g. 20 to 22 in the three anterior rows

115

on the left, and 18 to 20 in the posterior row,
On the right there are 18 to 20 in the anterior
rows, and 16 to 18 in the posterior row.

The gut loop is vertical, the oesophagus
relatively long and the more or less elliptical
stomach, with about 16 fine internal striations or
ridges in its glandular wall, is in the posterior third
of the abdomen. A distinct rectal valve separates
the rectum from the mid-intestine. A conspicuous
gastric reservoir is in the gut loop. Mature zooids
have a tight circle of 6 to 8 pear-shaped follicles
on the right side of the pole of the gut loop. They
converge to the centre of the circle where they
join the proximal end of the vas deferens. There
is often a small ovum (just posterior to the
proximal end of the vas deferens), and frequently
it projects from the side of the abdomen.

Specimens collected from the Capricorn Group
in March (QM GH4122) and May (QM GH4200)
have a single embryo in each brood pouch
(attached to the postero-dorsal corner of the
thorax).

Larvae have a trunk about |.5mm long, with
the tail wound three-quarters of the way around
it. Each of 3 tri-radially arranged adhesive organs
with stout stalks has a pair of ectodermal ampullae
near its base, An ocellus and an otolith are in
the cerebral vesicle. The larval test contains
pigment particles and looks frothy owing to the
packed bladder cells. This makes it difficult to
see the larval organs.

Remarks: The soft pink-lilac of this species is
similar to that of Distaplia violetta n.sp. and the
two species are readily confused in the field.
However, in the latter species both branchial and
cloacal apertures are much more conspicuous, the
colony is thicker and often stalked rather than
sessile, and it has purple and some brownish or
yellow pigment particles in the test while the
present species has purple and lavendar pigment
only. Zooids of D. violetta are readily distin-
guished, being larger, with conspicuous, relatively
broad external stomach folds and a posterior
abdomen containing the gonads.

The type specimen of Distaplia vallii Herdman,
1886 is from the Philippines. It consists of many
stalked heads arising from a common basal stolon,
each head consisting of a single system with double
rows of zooids converging to a single terminal
common cloacal aperture. The colony resembles
that of D. australiensis and is different from the
colonies of the present species with their several
circular systems that formerly were assigned to
D. vallii by Van Name (1918), Millar (1975) and
Kott (1981). The zooids of Herdman’s species are
distinguished also by their primarily oblique and

116 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 40, Distaplia cuscina n.sp.: a,b, zooids (holotype
QM GH4381 GH4123); ¢, larva (QM GH4122).
Scales: a,b, 0.5mm; c, 0.25mm.

transverse muscles. The other specimen Herdman
assigned to D. vaillii is from the Mediterranean
and it appears to be distinct from any of the Pacific
Ocean species (see Van Name 1918).

Distaplia tahihuero Monniot and Monniot,
1987 from Tahiti closely resembles the present
species both in colour and colony form. The zooids
of both species are of similar size, have the same
number of stigmata per row, and the same
internally ridged stomach. The ovum projects from
the side of the abdomen in the same way as it
often does in this and other species of Distaplia.
There are fewer (3 or 4) testis follicles in D.
tahiheuro and the larva is smaller than that of
the present species.

Kott (1981) suggested the synonymy of Distaplia
dubia (Oka, 1927c) with the present species.
However, D. dubia has a stomach with external
folds that more closely resembles that of D.
stylifera than the present species.

Distaplia dubia (Oka, 1927)

(Fig. 41a. Plate 9b)
Leptobotrylloides dubium Oka, 1927c, p. 607.
Distaplia dubia: Tokioka, 1953, p. 206; 1954c, p. 82;

1967c, p. 240.
Not Distaplia aff. dubia: Tokioka, 1967c, p. 240.
Distaplia japonica Tokioka, 1951b, p. 169.

DistRIBUTION

New Recorps: New South Wales (Lord Howe L.,
QM GHS2).

Previousty Recorpep: Japan (Japan Sea, Seto
Naiki Sea, Sagami Bay — Oka 1927c, Tokioka 1951b,
1953, 1954b, 1967c).

DESCRIPTION
EXTERNAL APPEARANCE: The colony forms a
fleshy encrusting sheet. The test has a soft, spongy

THE AUSTRALIAN ASCIDIACEA 2

117

Fic.41, Distaplia dubia: a, zooid (QM GHS2). Distaplia florida n.sp. b, colony (QM GH4164); ec. zo0id (holotype
QM GH4103); d, juvenile vegetative zooid (SAM E2039); e, branchial apertures, obscured by their enlarged
ventral lobes, surround a lobed common cloacal opening (MV F53292); f, larva (holatype QM GH4103). Scales;

ave,f, (.Smm; b: lem: ¢, |mm: d, 0.25mm.

consistency. Zooids are in circular systems. In life
the present specimen was blue-grey with orange
patches. When first preserved it contained dark
pigment cells in the surface, especially in the
vicinity of the zooids. However, long-term
preservation has left it a dirty beige colour.
INTERNAL Srrucrure,; The branchial aperture
has 6 shallow lobes. Three tongue-like projections
occur on the tip of the long atrial lip, The usual
fine longitudinal thoracic muscles oceur and dorsal

muscles curye out into the atrial tongue. The
thorax is about twice the length of the abdomen.

In the branchial sac 16 stigmata are in the 3
anterior rows on the left and 14 in the posterior
row, On the right 14 stigmata are in the anterior
rows and 12 in the posterior row. Parastigmatic
vessels were not detected, but it is possible they
have been lost or are obscured in these contracted
specimens. The oesophagus is fairly long and
curves horizontally to enter the obliquely oriented

118

stomach, which is shorter along its mesial side
than along its outer curved surface. The stomach
has 16 fine longitudinal folds. Gonads were not
detected in this specimen. It is probable they
develop in the gut loop, as a posterior abdominal
sac is not present and there would not be space
for one in these relatively thin sheet-like colonies.

Remarks: Although Lord Howe I. is geogra-
phically isolated from the Japanese location from
which this species has been recorded previously,
the specimen is indistinguishable from the
Japanese material. Tokioka (1953) described
specimens from Japan as greyish-brown, or shades
of pink, or dirty greyish-orange and the newly
recorded specimen is patterned in grey and orange.
The Japanese specimens have [5 to 20 stigmata
per row, 16 fine stomach folds can be observed
on the outer wall of the stomach, and the test
is the same consistency as the present species,

Amongst other species of this genus, its colony
most resembles D. cuscina n.sp. However, the
latter species has more stigmata per row, and
although its stomach has longitudinal ridges
internally, externally it is smooth. Distaplia viridis
from South Australia has similar systems, but is
distinguished by its more numerous stigmata and
smooth stomach. Distaplia pallida n.sp. does have
a folded stomach, but the folds are wider than
those in the present species and it has more
complex cloacal systems and fewer stigmata.

If this Lord Howe IL. specimen is correctly
assigned a much wider range is predicted for this
species,

Distaplia florida n-sp.
(Fig. 41b-f. Plate 9c,d)
DistRIBUTION
Type Locauiry: New South Wales (Julian Rocks
Bryon Bay, reef, 10m, coll. N, Coleman 30.3.75, holotype
QM GH4103).
FurtHer Recorps: South Australia (Great Austral-
ian Bight SAM E1999 E2039, QM GH4180 GH4184).
Tasmania (King 1, MV F53292).

DESCRIPTION

EXTERNAL APPEARANCE: Colonies form soft,
flat cushions about 4cm in diameter and slightly
less than lem thick. Zooids are in circular systems
—in groups of about 8 around each cloacal cavity
with its central cloacal opening. Cloacal apertures
are conspicuous, each on a protruding siphon that
rises from the centre of a depressed area. The
border of the aperture is divided into lobes into
which the atrial lips of the zooids are inserted.
Branchial apertures open around the outer walls
of the surface depressions. In the preserved
specimens, ventral lobes of each branchial aperture

MEMOIRS OF THE QUEENSLAND MUSEUM

are long and the openings are directed in toward
the cloacal aperture. Systems are evenly spaced,
with a small area of zooid free test between them.
The test has a spongy consistency. The surface
test over each system is extremely thin, and
possibly the surface depressions, over the zooids
and cloacal cavity, are inflated and raised in life,
Free larvae in the holotype colony beneath the
surface outside the circles of zooids are probably
about to be liberated.

In preservative colonies are grey, beige, or
pinkish-cyclamen, cloudy throughout and with red
pigment particles and clouds of white granules in
the surface. In life the holotype colony was purple
and pink (fide N. Coleman). Colonies from South
Australia were orange or dark red with distinct
black circles around cloacal apertures (fide S.
Shepherd QM GH4164) or very pale pink or cream
(SAM E1999),

INTERNAL StRuCTURE: Zooids are about 4mm
long, the thorax and abdomen about equal length
when the thorax is relaxed. The branchial aperture
has 6 lobes. The atrial aperture is wide, with a
pronounced anterior lip and some asymmetry of
the opening, depending on the zooid’s orientation
to the cloacal cavity.

Numerous fine longitudinal and oblique muscle
bands occur, the most dorsal curving out into the
atrial lip which is sometimes long and pointed.
The branchial opening is 6-lobed. On the left are
24 and 26 long, rectangular stigmata in the
posterior and each of the 3 anterior rows,
respectively. On the right are 24 stigmata in the
anterior 3 rows and 22 in the posterior row. Each
row is crossed by a parastigmatic vessel.

The abdomen is narrow, the gut forming a
vertical loop. The smooth, kidney-shaped,
yellowish stomach lies vertically in the posterior
half of the abdomen. The oesophagus is rather
long and narrow. A short, broad duodenal area
is separated from the rectum by a slight constric-
tion in the posterior end of the descending limb
of the gut loop. Gonads are in the gut loop,
although neither sex is mature in the type
specimen. In the buds scattered randomly in the
test between the adult zooids are well-developed
testes consisting of a circle of about 12 club-shaped
follicles converging into the proximal end of the
vas deferens in the centre of the circle.

Larvae, one in each brood pouch, are large,
the trunk being 2.5mm long. The tail is about
the same length as the trunk and, when curved
around it, barely reaches the anterior end. In the
mature larva the oozooid occupies the posterior
end of the trunk. It has a full complement of
stigmata with a parastigmatic vessel crossing each

THE AUSTRALIAN ASCIDIACEA 2

row. There is an ocellus and an otolith in the
cerebral vesicle. Five small buds move progres-
sively from the oesophageal region of the oozooid,
ventrally and then dorsally around the left side
of the middle of the trunk — i.e. around the base
of the adhesive apparatus that occupies the
anterior half of the trunk. The adhesive apparatus
consists of 3 large, anterior stalked adhesive
organs, 2 dorsal and one ventral, each consisting
of a central cone of columnar cells rising from
the base of a relatively shallow epidermal
concavity. The base of each of the stalks of the
adhesive organs is expanded into about 7 balloon-
like elongated ectodermal ampullae.

Remarks: The species resembles the South
Australian D. viridis, having similar circular
systems, zooids with similar body musculature,
a vertical gut loop with a smooth yellowish, kidney
shaped stomach, and gonads in the loop of the
gut. The present species is distinguished by having
larger zooids with more stigmata in each row, a
cushion- rather than sheet-like colony and a much
larger larval trunk with more elaborate adhesive
apparatus, and it lacks the dark pigmentation of
D. viridis, Distaplia pallida n.sp. is distinguished
by its sheet-like colony, its folded and horizontally
oriented stomach, fewer stigmata, more transpar-
ent test and small zooids.

The colonies of D. florida resemble those of
D. tokioka n.sp., as do the circular systems.
However the latter species has its gonads in a sac
posterior to the abdomen, while those of the
present species are in the gut loop.

Distaplia muriella n.sp.
(Fig. 42)
DistTRIBUTION

Type Locauiry: Western Australia (Blackwall Reach,
Swan River estuary, 20m muddy bottom, coll. 2.4.60,
holotype WAM 135.75; Swan River estuary, Rocky Bay,
at edge of channel, coll. WA Naturalists November 9,
paratypes WAM 32.75).

FurTHER Recorps: Western Australia (Swan River,
WAM 1003.83 17.87; Garden Island).

Apart from a single specimen recorded from Garden
Island, just outside the Swan River estuary, the records
of the species are from within the estuary — where
apparently it is indigenous, The Swan River estuary in
the vicinity of the type locality — Blackwall Reach —
has a deep pocket of salt water that persists through
the winter beneath the fresh water inundations that occur
at that time (Spencer 1956). At Rocky Bay, which is
on the opposite shore from Blackwall Reach, specimens
have been taken from intertidal and shallow water in
the summer when the salinity is marine.

DESCRIPTION
EXTERNAL APPEARANCE: Colonies are irregu-
lar. Some small mushroom-shaped, flat-topped,

119

zooid-bearing heads are supported on upright and
recumbent stalk-like outgrowths of common basal
test. Some are attached to a large worm tube by
a thin basal membrane (WAM 135.75). Also large
areas of the basal test thicken to 0.5cm beneath
irregularly shaped flat-topped zooid-bearing
lobes, 5cm in maximum extent. These lobes
slightly overlap the thickened basal test, and
sometimes one another, around their periphery.

Zooids usually are in double rows radiating
from 2 or 3 common cloacal openings in the centre
of the flat upper surface of the smaller mushroom-
like heads. In larger plate-like lobes the number
of common cloacal apertures increases and they
become more dispersed over the upper surface.
Zooids sometimes are arranged in a circle around
a cloacal aperture although as zooids are added
to the system, the double rows develop and radiate
out from the aperture. The test is soft and semi-
transparent. In preservative colonies are pastel
pink and blue, both colours occurring in the one
colony and sometimes in the one lobe, Some
specimens from Blackwall Beach are muddy grey
in preservative, owing to the mud content in the
gut of the zooids. The pigment is in particles in
the surface test.

INTERNAL Structure; The small branchial
aperture is terminal and is not lobed. The atrial
aperture is a wide opening with the upper border
produced into a long pointed lip. About 30 fine
muscle bands are on the thorax. Dorsal ones
extend across the dorsal line between the atrial
and branchial apertures, curving out into the atrial
lip; others radiate from the branchial aperture;
and the ventral ones extend from the endostyle
toward the postero-dorsal corner of the thorax.
Muscles are present, but are most inconspicuous
on the abdomen. There are 16 and 14 long
rectangular stigmata in anterior rows on left and
right respectively, and 14 and 12 in the posterior
rows, Fine parastigmatic vessels are present.

The long, elliptical, vertically oriented and rigid
stomach is yellow. It is smooth externally but
internally it is papillated. Occasionally the
papillations seem in longitudinal lines appearing
as fine longitudinal striations. The oesophagus is
constricted before it enters the stomach.

Gonads are in the gut loop and consist of a
rosette of up to 12 testis follicles with a large central
ovum and up to 2 smaller ones on the right side
of the gut loop. A long brood pouch is attached
by a long, narrow neck to the postero-dorsal
corner of the thorax to the right of the rectum.
The brood pouch, containing up to six embryos,
extends toward the base of the colony without
curving, although its distal tip is bent upwards.

MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 42, Distaplia muriella n.sp, (holotype WAM 135,75): a, colony; b, zooid; ¢, larva. Scales: a, 5mm; b, lmm;

¢, 0.5mm.

Developing embryos and tailed larvae are present
in the holotype and paratypes from the Swan River
taken in November.

Larvae are large, with a long (1.5mm) almost
cylindrical trunk and a tail only slightly longer.
There is an otolith and an ocellus in the cerebral
vesicle.

Remarks: Colonies resemble most closely those
of D. australiensis, with double row systems
radiating from cloacal apertures and extending
down the sides of the colony. However, zooids
differ, those of the present species having their
gonads in the loop of the gut rather than in a
postenior abdominal sac. Zooids of the tropical

species D. cuscina n.sp. are similar to those of
the present species, the stomach having the same
elliptical shape and vertical orientation, although
in D. cuscina the systems are more consistently
circular, the number of stigmata in each row is
greater, the stomach has internal ridges, and the
oesophagus is not constricted before it enters the
stomach,

Other known species with a smooth stomach
and gonads enclosed in the abdomen, viz. D.
regina n.sp., D. florida nsp. and D. racemosa
n.sp., haye circular rather than double row systems
converging to terminal cloacal apertures, and their
colonies are cushion-shaped rather than stalked.

THE AUSTRALIAN ASCIDIACEA 2 121

The constriction at the distal end of the
oesophagus just before it enters the stomach is
an unique feature in D. muriella helping to
distinguish it from all other species. The numerous
(6) embryos in the brood pouch are an unusual
feature of the present species which it shares with
D. ausiraliensis (which has from one to 5).
Distaplia violetta n,sp. sometimes has 3 but other
species have no more than one.

Colonies of this species from the Swan River
estuary in both April and November are in an
active state — sexual reproduction as well as
vegetative replication occurring in the same colony
at these times.

Distaplia pallida n.sp.
(Fig, 43. Plate 9e)
Distaplia viridis: Kott, 1972a, p. 7 (part, fig. 6 specimens
from Hallett Cove).

:
N
N
é

DisTRIBUTION

Typrc Locatrry: Victoria (Portsea, on jetty pile, 4m,
coll. N. Coleman 13.3,75, holotype QM GH4102; 2m,
coll, G. Russ 163,78, paratype QM G] 1923),

Furtner Recoros; South Australia (St Vincent Gulf
~ SAM E1998 Kott 1972a; Great Australian Bight
QM GAH 4189). Victoria (Portsea, QM G11924),
Tasmania (Tinderbox, QM G9994).

DESCRIPTION

EXTERNAL APPEARANCE: The sheet-like colo-
nies are thin (not more than 0.5cm thick) and
sometimes extensive. growing around rubble. In
preservative the test is gelatinous and almost
transparent, and the zooids show through it as
white dots. Zogids are in circular to oval systems
of up to 15 zooids. Each system has a cloacal
aperture at its centre or toward one end.
Sometimes one end of an oval system is extended
into a short, double row, The living specimens

Fic. 43, Distaplia pallida n.sp. a, arrangement of zo0ids in system (paratype QM G11923); b, zooid (paratype
QM G11923); ¢, larva (SAM E1998). Scales; a, 2mm: bye, 0.5mm.

122

ure a pule to bright vellow and orange (QM
GH4189), or the zooids are orange in a transparent
tesL (SAM E1998).

INTERNAL Strucrurm Zooids with a con-
tracted thorax ure up to 3mm long, but usually
aré smaller, About 20 fine longitudinal and oblique
Touscles are present on the thorax. There are 6
small branchial lobes, The atrial aperture is the
usual wide asymmetrical opening, It has a long
antertor lip with 3 or4 pointed or rounded tooth-
like projections along its (at-ended outer tip,
which is often oblique and asymmetrical rather
than straigtt, corresponding to the asymmetry of
the opening itself. Muscles extend from the
branchial aperture along the centre of the atrial
lip, crossing the dorsal muscles that curve outinto
the lip.

On the left are 10 and 12 Stigmata in the
posterior and each of the three anterior rows of
sligmata respectively, and on the right the numbers
are 10 in the anterior rows and 8 in the postertor
row. Each row is crossed by a parastigmatic vessel,

About halfway down, the ocsophagus makes
an abrupt, night angled bend toward the ventral
surface Lo enter the stomach, which is short and
almost barrel-shaped and lies at right angles to
the longitudinal axis of the zovid. The stoniach
has about 12 deep, rounded folds at its cardiac
end. Vhese fade out at the pyloric end, where the
stomach narrows. The duodenal region of the gut
turns posteriorly, at right angles to the long axis
of the stomach, The mid-intestine occupies the
distal part of the descending limb of the gut loop
hefore narrowing shghuly to open into the rectum
where, in some specimens with an empty gut, a
rectal valve can be seen. Thus the gut loop frames
an almost rectangular area in the lower half of
the abdomen. Gonads are in the gut loop and
consist of a circle of male follicles and a single
egg.

Gonads aré mature in specimens collected from
South Austraha in December (SAM E1998). but
not in any of the colonies collected in March or
April, There are vegetative buds in the test
amongst the adult zoojds, but no gonads were
observed jn these small vegetative individuals.

One tailed larva is present in each brood pouch
in colonies collected fram St Vineent Gulf in
December (SAM E1998), The trunk 1s almost
spherical, |.35mm long with a short tail extending
only about one-third of the way around the
circumference of the trunk, The 3 triradially
arranged, almost sessile adhesive organs are on
a frontal plate. Four rows of stigmata are present,
together with ocellus, otolith and @ well developed
gut loop.

MEMOIRS OF THE QUEENSLAND MUSEUM

Remarks. In preservative. these investing
colonies can be nustaken for the sympatne 2.
viridis or D, tokioka np. Dixtaplia pallida is
distinguished from D. viridis by its smaller zooids
with fewer stigmata, larger and more variable
systems, the right-angled bend in the oesophagus,
deeply folded stomach, more transparent and less
spongy test, and pigmentation ol the living colony.
Distaplia tokloka asp. has similar colonies but
ils gonads are in w posterior abdomen,

The zooids of D. dubia (Oka, 1927c) trom Japan
and Lord Howe [. (see above, D. dubia) most
closely resemble those ol the present species, but
they have more numerous stomach folds, more
stigmata and form more regularly circular systems.

Distaplia cuseina n.sp, has more stigmata than
the present species, does not form such extensive
sheet-like colonies, and has simple, circular cloacal
systems and a vertically oriented stomach with
conspicuous internal ridges.

Distaplia pallida resembles //ypsistezoa disto-
moides and the New Zealand H. /asmeriana —
both species huving deep rounded stomach lolds,
a horizontally oriented stomach, and similar
numbers of stigmata, However, /Typsixtozea spp.
have stalked or upright colonics, never sheet-like
ones like those of D, pallida, and they have
conspicuous longitudinal muscles on the posterior
abdominal vascular appendix, as well as gonads
posterior to the gut loop.

Distaplia prolifera n.sp.
(Fig. 44a,b)
Dist kino tlon
Typeu Locavery: Western Australia (1b nautical mls
NW Port Hedland, 20°12 LI8"25’E, 14m, coll, L.
Marsh on RY Soela 5.8.82. holotype WAM 812.83 OM
GH213),

FURTHER Reeoros None.

Discrirtion

Exrirsar Arrnaranct: The single available
colony is large and irregular, completely investing
a large branching algal stalk. lity maximum
dimension is 15cm und its maximum thickness is
lem, The testis tough and spongy. In preservative
it is pink, owing to pink pigment particles
embedded in the surface test. Zooids are in circular
to oval systems, and in the preserved colames the
surface test is slightly depressed over the systems.

INTERNAL STRUCTURE Zoos are large, being
about 4mm long. even with the thorax contracted
They have a long oesophageal neck that is more
than hall the length of the abdomen. Gonads are
in a sac posterior to the abdomen. attached to
ithe right side of the gut loop by a narrow neck
About 34 fine longitudinal museles are on the

THE AUSTRALIAN ASCIDIACEA 2

Fig, 44, Distaplia prelifera n.sp. (holotype WAM 812.83): a, zooid; b, larva. Distaplia racemosa n.sp. (holotype
NTM E9): e, zooid: d, larva. Distaplia regina n.sp. (holotype QM GH4201): e, zovid. Scales: a-e, 0.5mm.

thorax, including those that cross the dorsal mid-
line between the apertures and continue around
the atrial aperture. The branchial aperture is 6-
lobed. Sometimes the atrial aperture is wide open
exposing the dorsal part of the branchial sac, but
sometimes it is produced out on the end of a
siphon. There is only a short pointed lip from

the upper border of the atrial opening. On the
left 18 stigmata are in each of the 3 anterior rows
and 16 in the posterior row. On the right 16
stigmata are in the anterior 3 rows and [4 in the
posterior row. A parastigmatic vessel crosses each
row of stigmata.

The stomach is in the posterior third of the

124

abdomen. The distal end of the oesophagus turns
slightly toward the ventral surface before entering
the stomach and the oval stomach is itself slightly
obliquely oriented. The stomach is not folded,
although its internal wall has about 20 fine
longitudinal striations in its glandular lining. The
mid-intestine opens into the rectum in the pole
of the gut loop and there is a distinct rectal valve.
A long elliptical gastric reservoir lies in the gut
loop.

Four long testis follicles are in the posterior
abdomen. They are longitudinally oriented,
opening into the vas deferens at their posterior
ends. A small ovum is also present at the posterior
end of the abdomen near the proximal end of
the vas deferens. In this holotype colony, collected
in August, there is a single well-developed embryo
in each brood pouch. The brood pouches are
present in the test behind the zooids, attached to
the thorax by a long narrow neck, often hard to
distinguish in the rather tough test.

Larvae are large, the oval trunk being 2.2mm
long. The tail is relatively short, reaching only
to the anterior end of the trunk. There is an otolith
and an ocellus in the cerebral vesicle. The large
adhesive organs occupy the anterior third of the
trunk. Each adhesive organ has a single large
balloon-like expansion at the base of its stalk.
There, are two small buds from the oesophageal
region of the oozooid,

Remarks: Although Distaplia pallida n.sp. also
has an investing colony and zooids arranged in
circular to oval systems, it is distinguished from
the present species by the absence of a posterior
abdominal sac — its gonads being enclosed in the
gut loop. Distaplia tokioka n.sp. has investing
colonies and gonads in a posterior abdominal sac
like those of the present species but its stomach
wall is folded. Other species with their gonads in
a posterior abdominal sac form stalked colonies
that are readily distinguished from the present
investing species. Further, both zooids and larvae
of D. violetta n.sp. and D. stylifera are smaller
than those of D. prolifera n.sp.

Distaplia racemosa n.sp.
(Fig. 44c,d)

DistTRIBUTION

Type cocattry: Northern Territory (Arafura Sea,
Cootamundra Shoals, 10°49'49,966’S 129° 12’54.876’E,
36m, coll. R. Lockyer 6.5.82, holotype NIM E9 QM
GH4366),

FurtHer Recorps: None.

DESCRIPTION
ExTerRNAL APPEARANCE: The colony is invest-
ing, growing around a narrow woody stem. It is

MEMOIRS OF THE QUEENSLAND MUSEUM

long. The edges have partially joined together
along one side so it appears to be a cylinder of
about 2cm diameter. Thus the species will
probably be found as a flat, investing sheet when
taken from other substrates. There are regular
circular systems of about 6 zooids. The systems
are evenly spaced, the cloacal apertures being
about Icm apart. In the preserved specimen the
surtace of the colony is depressed over each system.

The colony is firm, owing to the thick (0.5cm)
gelatinous and translucent but firm outer layer
of test at thoracic level. The inner test around
and posterior to the abdomen is soft, spongy and
almost opaque, containing the posterior abdom-
inal stolons and developing vegetative zooids. The
outer translucent layer of test is pale pink in
preservative. The soft inner layer is white.

INTERNAL STRUCTURE: Zooids are about 6mm
long. The body wall has conspicuous fine
horizontal muscle bands crossing the sides of the
body from the endostyle. Short longitudinal bands
radiate from the branchial aperture over the
anterior end of the thorax to the level of the second
row of stigmata. The branchial siphon is short
and its border is divided into 6 shallow lobes. The
large anterior atrial lip has 3 fine projecting
tongues along its terminal edge. This lip is inserted
into the test around the cloacal aperture. There
are 4 rows of long stigmata, 26 in the anterior
3 rows and 24 in the posterior row. Each row
is crossed by a fine parastigmatic vessel. The
oesophagus is long and narrow. The relatively
short, smooth-walled and slightly obliquely
oriented stomach is about halfway down the
abdomen. There is a small oval posterior stomach.
The gut loop encloses a spherical mass of short,
only slightly pyriform testis follicles. A single
ovum is present on the right side of the testis at
the base of the vas deferens,

Embryos and tailed larvae are present in the
test at oesophageal level, the stalk of the brood
pouch being relatively short. Only a single embryo
develops in each brood pouch. Larvae have a trunk
1.8mm long and a relatively short tail reaching
about halfway around the trunk. They have an
ocellus and a small otolith. The triradially
arranged adhesive organs have short stalks that
are not expanded at their base.

Remarks: Only the holotype colony is avail-
able. Its size and its well-separated and evenly
distributed circular systems are distinctive, as is
the outer firm gelatinous layer of test that is of
entirely different consistency from the basal test.
The zooids with their predominantly transverse
musculature most closely resemble those of the
Japanese D. systematica Tokioka, 1958 (described

THE AUSTRALIAN ASCIDIACEA 2

from a single colony) and the possibly conspecific
specimen from Toeal (specimen 2.1i1.1922)
assigned to 2). stylifera by Millar (1975). lokioka’s
(1958) specimen had no gonads. The testis in the
colony from Toeal is not the same spherical muss
of crowded male follicles as that found in the
present species. Further, both Japanese and Toeal
material consist of separate stalked lobes, arising
from a common base, each lobe containing u single
<ircular system. Although it is possible these
colonies are juveniles, and each lobe could develop
to accommodate numerous circular systems (as
inthe present species), the growth pattern, in which
additional lobes are added to the colony, appears
different from the shect-like D. racemosa.

The circular systems and the zowids of the
present species resermble those of D. viridis,
although the longitudinal thoracic muscles are
more conspicuous in the litter species and it has
more stigmata,

The relatively numerous branchial stigmata and
the sheet-like form of the colony are characters
shared with the temperate species D. florida
which, however, has more crowded circular
systems and larvae with numerous ectodermal
ampullae at the anterior end of the trunk, The
relatively large larvae of the present species,
without expansions at the base ol the adhesive
organs, are characteristic,

Distaplia regina n.sp.
(Fig. 44e)
Dis iu ian
Tyrn Locaey: Queensland (Heron |, Capricorm
Group, low tide, under side of rubble. call, P. Kou
25.5.87, holotype QM GH4201; paratype OM GH4202).
Furrucr Rreorps: None.

DescriPTion

FxrerwaAL Avpeanance: Colonies are soft and
irregular cushions 2 to 3¢m in maximum diameter
and less than 5mm thick. Zooids are arranged in
circular sysiems around sessile cloacal apertures.
Living colonies are dark purple with clouds of
white particles in the surface test, These are
concentrated over the atrial lips to form a white
patch in the centre af each system in the vicinity
of the cloacal aperture. Immediately on fixation
with formalin the colour of the colony changes
to, and remains, cloudy pink. Dark red-brown
pigment cells were in the test after a period in
preservative, The test has the spongy consistency
of so many species of this genus.

InreRNAL Srructurr; Zovids are about 3mm
long when contracted, They are almost opaque
in preservative, with a greenish translucent
stomach and proximal part (descending limb) of

125

the intestine. ‘There are 6 pointed branchial lobes.
‘The atrial Opening is large with a long pnterior
lip and 3 langues on its ouler Up, About IS
longitudinal thoracic museles extend trom the
branchial siphon. Other fine muscles cross the mid-
line dorsal to the branchial siphon, some curving
OU inte the atrial lip and then continuing down
each side of the atrial aperture. No oblique or
Iransverse muscles originating from the ventral
mid-line were observed in these zooids,

The stigmata are moderately long and rectan-
vular, bul no parastigmatic vessels were detected
in these specimens. On the right side of the
branchial sac sre 20 stigmata in cach of the 3
anterior rows and [8 in the posterior row; and
oo the left [8 in each of the anterior rows atid
16 in the posterior row.

The abdomen js relatively large, the gut being
especially voluminous. [he large stomach is about
hallway down the abdomen, more or less verucally
oriented in the vertical gut loop. It is spherical
ar shghtly oblong, Externally its wall is smouth
but internally the glandular epithelium is raised
in short ridges or papillae to form a reticular
pattern When seen from the outside. The shert
ridges ure oblique or transverse, seldom longilud-
inal. A short duodenal area narrows before it
enters the rectum, where there is # distinct rectal
valve, The gut loop encloses a circle of about 5
club- to wedge-shaped testis follicles, These join
the vas deferens in the centre ol the circle. A single
cyy is sumelimes present near the proximal end
of the vas deferens, It projects slightly from the
side of the abdomen. There is a rudimentary brood
pouch allached by a narrow neck to the postero-
dorsal corner of the thorax just lo the right of
the mid-line. No embryos Were being brooded i
either the holotype or paratype colony.

Remarks, Although the soft cushion-like
colony, the systems, and the numbers of stigmata
present in this species resemble those of L. cuseina
nsp., zoids are larger and the gut, especially the
almost spherical, roomy stomach with its unique
internal paliern and vreenish translucent colour,
are distinctive. Disraplia yezoensis Tokinka,
1951a, from Japan, has both colony and zooids
(including the reticular pattern in the internal
stomach lining) that resemble those of the present
species, The Japanese species has fewer stigmata
(12 to 13) and it has conspicuous parastigmatic
vessels. Lt appears La be a separate species.

Distaplia retinaculata n.sp.

Dis re inily tor (Fig. 45)

Tyee Loeacis Vietoria ().5km aff MeGuurun's
Beuch, Ninety Mile Beach, reef (5m coll, JE, Watson

R7E/8 1977, holotype MV F53267 OM GH3i27; R3F/
44 paratype MV F53268).

DESCRIPTION

EXTERNAL APPEARANCE: Colonies are soft,
fleshy, cylindrical and rope-like, up to lem in
diameter. In all recorded specimens much of the
surface of the colony appears to be disintegrating,
and systems are disrupted. However, there are
entire areas where zooids are in crowded circular
systems of about 12 around large common cloacal
apertures up to 2mm in diameter. Some dark grey
pigment particles are present in the surface test
of the preserved colonies. The soft centre of the
cylindrical colony is filled with a tangle of fine
Vascular processes,

InteRNAL STRUCTURE: Zooids are about 4mm
long. The branchial aperture is 6-lobed. The atrial
aperture is wide with a pronounced lip from its
upper border. The free terminal border of the atrial
lip is divided into 3 or 4 $mali tongues. Longi-
tudinal and oblique muscles are on the thorax,
and fine fibres extend along each side of the
abdomen, The branchial sac has 20 stigmata in
the anterior rows and 18 in the posterior row.
A fine parastigmatic vessel extends across each
row of stigmata.

The oesophageal neck is rather long, being more
than half the length of the abdomen, There is 10
posterior abdominal sac. The vertical, oval
stomach. in the anterior balf of the posterior third
of the abdomen, is smooth externally. Internally
it has numerous fine and mostly longitudimal
striations in its glandular wall. A short, broad mid-
intestine postenor to the stomach opens into the
wider rectum. The proximal part of the rectum
curves around to form the pole of the gut loup.
Gonads, consisting of a circular to hemispherical
mass of about 10 pear-shaped male follicles and
a large ovum are present just to the right of ihe
posteriar end of the gut loop. The vas deferens
makes a loop over the surface of the ovum. Gonads
are present in the vegetatively produced zooids,
which are present in the test between the adult
zooids. In these vegetative zooids the ovum
protrudes from the side of the abdomen and is
connected to it by a narrow stalk, Large yellowish
embryos(?) lie free in the test in the centre of the
colony. They do not appear to bein a brood pouch
and probably rupture from the abdomen into the
test, presumably after fertilisation.

In most of the zooids there are two vascular
processes from the left side of the gut loop.

Remarks. This species most closely resemble
Distaplia cvlindrice (Lesson) from the Antarctic
(see Kott 1969) which also often is found in a

MEMOIRS OF THE QUEENSLAND MUSEUM

similar disintegrated condition. The Antarctic
species has more numerous stigmata in the
branchial sac and distinct ridges in the stomach
wall. Although it has not been reported for the
present species, it is possible that the long
cylindrical zooid-bearing heads break away from
the substrate and float near the surface of the sea
as the Antarctic species is known to da (Kott 1969).

Although their colonies are distinctive, the
zooids of the present species most resemble those
of D. viridis which also have a smooth stomach,
ihe same numbers of stigmata, similar circular
systems and an ovum projecting in a sack from
the side of the gut loop in small vegetatively
produced zooids.

The brooding of the embryos in the test, and
their release directly from the abdomen is a
phenomenon associated with large eggs. It always
occurs in the Didemnidae and in the genera
Hypedistoma and Polydistoma n.gen. It is nat
known to occur in any other species of Distaplia.
The larva is not known for this species.

Fie, 45, Distanplia retinaculata asp. (holotype MV
F53267):.a, 2ooid; b. abdomen vo! yegetattye zoold
with precocious gonads. Scales: a, }mm; b. {),245mm.

THE AUSTRALIAN ASCIDIACEA 2

Distaplia stylifera (Kowalevsky, 1874)
(Fig. 46. Plate 9f,g)

Didemnium stylifera Kowalevsky, 1874, p. 443.

Distaplia stylifera: Michaelsen, 1930, p. 502. Brewin,
1953, p. 60. Kott, 1957a, p. 95; 1972b, p. 170. Millar,
1963a, p. 713; ? 1975, p. 224 (part, ZMC, 19.iv,1922
from Toeal). ? Monniot, 1988, p. 197.

Distaplia magnilarva: Seeliger, 1907, p. 1018.

Distaplia mikropnoa: Hartmeyer, 1919, p. 130, Tokioka,
1955a, p, Sl; 1967a, p, 130.

DistTRIBUTION

New Recorps: Western Australia (Houtman’s
Abrolhos, WAM 808.83; Shark Bay, WAM 809-11.83;
Triggs 1, WAM 33,72 14-5.84; Cockburn Sound, WAM
40.72 69.75 140.75 142.75 207.75 22.84), South Australia
(Great Australian Bight, QM GH943 GH970 GH2292
GH2302 GH2407). Queensland (Hervey Bay, QM
GH4129; Wistari Reef, QM GH4132; Heron L, QM
GH4203).

Previousty Rercorpep: Western Australia (Broome,
Roebuck Bay — Millar 1963a. Cape Jaubert
Hartmeyer 1919; Shark Bay Michaelsen 1930:
Cockburn Sound Brewin 1953, AM YII80 YII85
Kott 1957a, Millar 1963a). South Australia (Great
Australia Bight — SAM E1997 Kott 1972b). Palau Is
(Tokioka 1955b, 1967a). ? Philippines (Millar 1975). Red
Sea (Kowalevsky 1874),

It is surprising that with such a wide range the species
has been recorded only twice from the eastern coast
of Australia, and not at all from the western Pacific
Ocean. The Queensland records are of a specimen cast
up after a stiff northerly gale (fide G. McKoen, QM
GH4129) and two orange-vermilion (Ridgeway 1886)
colomes from the Capricorn Group (QM GH4132
GH4203),

DESCRIPTION

EXTERNAL APPEARANCE: Colonies are
mushroom- or toadstool-shaped, the zooid
bearing head being rounded to conical and the
stalk short and fleshy. Sometimes a number (up
to 6) of heads branch off the top of a common
stalk or they arise from a common basal mass
of test. The stalk is often cylindrical and the base
of the zooid-bearing head may overlap it. In other
colonies the stalk expands at the top and its
junction with the head is not sharply defined. The
zooids are arranged in circular, oval and long
radiating double row systems all over the head.
The common cloacal apertures have 5 or 6 lobes.
The test is firm and of a spongy consistency.

Living colonies are pink-red, orange vermilion
(Ridgeway 1886) or beige with golden zooids. The
colony cast up on the Queensland coast is reported
to have been a rich orange. In preservative all
colonies are the same beige colour, although
sometimes a trace of red pigment is present in
parts of the zooids.

127

INTERNAL STRUCTURE; Zooids are about 3mm
long, excluding the posterior abdominal sac that
contains the gonads, The branchial apertures are
6-lobed. The atrial apertures are wide with an
anterior lip that is pointed or flattened with 2 to
5 small teeth projecting from its terminal border.
There are about 30 longitudinal and oblique
thoracic muscles, and more variation in the
number of stigmata in each row than ts usual in
this genus. In specimens from Western Australia,
South Australia and Queensland, respectively, the
maximum number (in the left anterior rows) is
18, 16 and 14. There are, as usual, 2 stigmata
less in the posterior rows than in the anterior rows;
and 2 more in rows on the left than in corres-
ponding rows on the right. Parastigmatic vessels
were not detected in any of the specimens except
the one from Hervey Bay (QM GH4129),

The oesophagus bends ventrally to enter the
shield-shaped stomach which has a long curved
ventral border and a much shorter dorsal border.
The stomach has 16 to 20 distinct curved,
longitudinal folds, some of which branch. A large
oval gastric reservoir lies in the gut loop. The mid-
intestine is separated from the rectum by a distinct
rectal valve,

Gonads are present in a small sac behind the
abdomen, although it does not always have a
particulary narrow neck separating it from the
abdomen. The testis consists of a grape-like cluster
of up to 15 pear-shaped follicles. Often a large
ovum lies alongside the testis. The vas deferens
extends over the surface of the ovum in a
convoluted course. In one Queensland specimen
(QM GH4203) there are only 6 wedge shaped male
follicles crowded together in a circle. In this
specimen the posterior abdomen ts connected to
the left side of the abdomen by only a short neck.
This specimen and some from north western
Australia (WAM 977-8.83) have the triangular
body that was described by Tokioka (1967a)
alongside the ascending limb of the gut loop. It
is yellowish and translucent. It does not appear
to be part of the gastric gland, as Tokioka
suggested.

A single embryo is in the relatively short-necked
brood pouch in specimens collected from Western
Australia in January (WAM 22.84), April (WAM
809.83) and December (WAM 140.75). However,
other specimens collected in those and other
months from both Western Australia and South
Australia do not have embryos.

Larvae have an almost spherical trunk, 1.2mm
long and only slightly longer than deep. The whole
stalk of each adhesive organ appears expanded

128 MEMOIRS OF THE QUEENSLAND MUSEUM

0,
2200 QOdD000000
“20, 0009 00q000
%, 0
> 0000aQq
0009,
0

0096,

000

Fic. 46, Distaplia stylifera: a-c, colonies (QM GH2407, WAM 810.83 808.83); d,e, zooids (WAM 808.83, QM
GH2292); f, larva (WAM 810.83). Scales: a, 5mm; b,c, lcm; d-f, 0.5mm.

THE AUSTRALIAN ASCIDIACEA 2

into a balloon-shape. There is an ocellus und an
Otolith in the cerebral Vesicle,

Remaerxs: Michaelsen (1930) believed that 1).
hursata (Van Name. 1921) from the West Indies
was a synonym ol D. srylifera from the Red Sea
and north-western Australia, and other authors
have followed him in this. Although the colonies
and even the pigmentation as well as seme
characteristics of the zooids including the numbers
of stigmata are identical, the West Indian species
hay a narrow-necked posterior-abdominal sac
containing only 6 long testis follicles that more
closely resemble those of 2. weavtraliensiy than the
\sually numerous, shorter folligles of the present
Species.

Some of the specimens trom the Philippines
(ZMC 19.iv.1922) with stalked colonies, circular
systems and bunched testis follicles that were
referred to 1). stvlifera by Millar (1975) probably
do belong to this species, although other specimens
have the purastigmatic vessels, several embryos
in the brood pouch and the longer larval trunk
of D. vivletta nsp. Specimens from New Cale-
donia assigned to D. stylifera by Monniot (1988)
may also belong to D, violeria nsp. They have
parastigmatic vessels, lew male follicles, circular
systems and are grey-green (in preservative’).

Tokioka (1955b, 19474) used the ubsence o!
parastigmatic vessels to distinguish 2. mikropnoa
(Sluiter, 1909) from D. srylifera. However,,
parastigmatic vessels were not recorded in the lype
ol D. sivlifera trom the Red Sea and as the species
has not been taken since from that location it is
not possible to confirm their absence. Parastig-
matic vessels are not present in specimens assigned
to both OD. sivlifera and D. mikropnoa trom
Western Australia, Indonesia and the Palau Is (see
Sluiter 1909, Hartmeyer (919, Michaelsen 1930
und Tokioka 1955b, 19672), In specimens assigned
to both species (sec synonymy, above) the male
follicles usually are numerous, short, pear-shaped
and bunched together, although in some specimens:
(tike those described by Michaelsen [930) there
are as few as 6 relatively large wedge-shaped
follicles crowded together in a ring (see also QM
GH4203). Thus, neither the presence nor absence
of parastigmatic vessels nor the number of male
follicles afford a means of distinguishing between
D, mikropnoa and D. stplifera.

In fact, most of the specimens assigned to 7),
mikropnoa appear to be conspecific with D.
stylifera, Distaplia mikropnoa (> Polyelinum
mikropnous Stuiter, 1909) appears a distinet
species separated from J), stylifera by its colony
form, long oval stomach oriented in the longi-
tudinal axis of the body, and branching network

124

of stomach folds. The (ype specimen is a large
sponge-like mass 4em wide. Gem long and up te
8mm thick — different fromm the stalked upright
colonies that characterise D, siplifera.

Some of the larger colonies resemble those of
Hypsistozea disiomoides which also has a thick.
fleshy stalk. In the absence of the characteristically
located gonads, ff. divtuntaides can be distin-
fuished by the conspicuous muscles on its vascular
process and its less numerous stomach folds. The
convoluted course of the proximal part of the vas
deferens in the present specimens is similar to that
in J. retinaculata n.sp,

Distaplia tokioka n.sp.
(Fig. 473,b)
DIsTRinu ign
Tye Locarie South Australia (Great Australien
Bight, Price |, Avoid Bay, 15 20m, coll, N. Holmes
9.4.87, holotype SAM P2081, paratypes GH41749),

Desc RIPTION

Exipenar Areranancy The type material
consists of numerous sessile, wregularly shaped
cushion-like Colonies, up to Sim thick and @em
in maximum dimension, investing weed stalks and
fronds. Zooids are arranged in circular systems
Common cloacal apertures. about 5mm sparc.
protrude from the surface as rounded preminen-
ces. their borders entire, and not divided into lobes
The testis firm, with the usual spongy consistency
of most species of this genus.

InieeNar Srruciiuen Contracted sooids are
about 2mm long excluding the posterior abdom-
inal sac which is connected to the abdomen by
a short but narrow neck, There ore 6 well defined
triangular branchial lobes. The atrial aperture has
the usual large anterior lip with 2 or 3 pointed
terminal processes. Thoracic muscles dre conspic-
vous, and appear all longitudinal, about 20
extending from around the branchial siphon, and
additional bands curving out into the atrial lip
and down along each side of the aperture. ‘The
branchial sphincter is well developed,

On the fight are [6 stigmata in the anterior 3
rows and 14 in the posterior row, and on the lell
14 and 12 respectively. Parastigmatic vessels are
present. The oesophagus bends ventrally Lo eriter
the almost horizontal and rather long stomach,
which has about 12 tongitudinal folds in its wall
A conspicuous spherical gastric reservoir lies in
the rather wide gut loop.

Gonads are not mature in these specimens
However, some szooids haye small, tear-drop-
shaped posteriur abdumina, attached by a
relatively long narrow neck, lo the right side ol

130

the abdomen. They contain small, pear-shaped
testis follicles.

Remarks: Externally, this species resembles D.
viridis and Distaplia pallida n.sp. Although the
individual colonies are not as extensive, their shape
may be affected by the substrate, in this case weed
fronds and stalks. Further, the geographic range
of both D. viridis and D. pallida includes the type
locality of the present species. However, although
D. pallida has a similar number of gastric folds,
it is readily distinguished by the presence of the
gonads in the abdomen rather than in a posterior
abdominal sac. Distaplia viridis has similar
circular systems and conspicuous protruding
cloacal apertures, but also has gonads in the
abdomen rather than in a posterior abdominal
sac, and it has more stigmata and lacks stomach
folds.

Amongst the species that do have a posterior
abdominal sac, the tropical Distaplia violetta n.sp.
resembles the present species in its circular systems
and number of stomach folds. However, it has
thicker colonies, conspicuously lobed cloacal
apertures and more numerous stigmata.

Distaplia stylifera, with similar short male
follicles bunched in the posterior abdomen, and
often simple circular systems as in the present
species, has more numerous stigmata and stomach
folds, and lacks parastigmatic vessels. Further
although there are many paratype colonies of the
present new species, not one of them has the stalk
that usually is characteristic of D. stvlifera.
Distaplia prolifera has a smooth stomach with
longitudinal striations internally and only 4 long
male follicles.

Distaplia violetta n.sp.
(Fig. 47c-e)

? Distaplia stylifera: Millar, 1975, p. 224 (part, specimens

ZMC 17-22.ii1.1914). Monniot, 1988, p. 197.
DISTRIBUTION

Typr Locatrry: Queensland (Capricorn Group,
Wistari Reef, low tide rubble fauna, coll. P.K. 5.8.82,
holotype QM GH1358; Heron | coll. P-K. May 1985,
paratypes QM GH4130, May 1987, QM GH4204).

Furruer Recorbs: Queensland (Capricorn Group,
QM GH4131 GH4133 GH4135-7 GH4205-9 GH4439;
Townsville, QM GH4138). ? Philippines (Millar 1975).
? New Caledonia (Monniot 1988).
DESCRIPTION

EXTERNAL ABPEARANCE: Colonies are small,
sessile flat-topped platforms about Icm high, with
thick basal test, and with the wide, flat, upper
surface narrowing toward the base and sometimes
forming a short fleshy stalk. Zooids are in circular
systems around conspicuous projecting cloacal

MEMOIRS OF THE QUEENSLAND MUSEUM

apertures with 5-lobed rims. Each system is about
4mm in diameter. Zooids are always vertical and
parallel to one another, opening only on the top
and never on the sides of a colony. The test has
a spongy consistency.

The colour of the living colonies results from
mixtures of dark "pansy purple’ (Ridgeway 1886)
pigment cells with clouds of opaque white particles
in the surface test. Sometimes some yellow or
brown pigment is also in the centre of the cloacal
systems. Thus resulting colours vary, being flesh-
coloured, blue, mauve with pink, plum coloured
test with pink zooids, In preservative, colonies are
green, with indigo blue pigment cells in the surface
test and green in the remainder of the test.

INTERNAL STRUCTURE: Zooids are less than
3mm long, excluding the posterior abdominal sac
which is joined to the right side of the posterior
end of the abdomen by a fairly long, narrow neck.
The thorax is longer than the abdomen, The
branchial lobes are large and triangular, those on
the ventral part of the opening projecting in front
of the dorsal ones. The atrial aperture is the usual
wide opening, although it is sometimes produced
forwards into a funnel-shaped siphon protecting
the branchial sac from direct exposure to the
cloacal cavity. A pointed lip is produced from the
anterior rim of the atrial aperture. There are about
20 fine longitudinal muscle bands on the thorax

some extending across the dorsal mid-line
between the apertures and curving out into the
atrial lip. On the left are 20 stigmata in each of
the anterior 3 rows and [8 in the posterior row;
on the right, are 18 and 16 respectively. Paras-
tigmatic vessels are present.

The oesophagus bends ventrally to enter the
curved stomach about halfway down the abdo-
men. The stomach has 8 to 12 folds that flatten
out toward the pyloric end, where the diameter
of the stomach decreases. These are true stomach
folds rather than internal ridges, as the whole
stomach wall is folded. There is a short, narrow
mid-intestine and a distinct rectal valve where the
intestine Opens into the rectum in the pole of the
gut loop.

A tight group of 4 to 6 relatively short, wedge-
shaped male follicles is in the posterior abdominal
sac. Three small ova are often at the outer end
of the male follicles — where they join the vas
deferens. A single, well-formed embryo is present
in the long-necked brood pouches of some of the
specimens collected in May (QM GH4208).
August (QM GH1358 GH4439) and November
(QM GH4137) from the Capricorn Group. In one
colony up to 2 large eggs were in each brood pouch,
as well as a well advanced larva. No embryos were

THE AUSTRALIAN ASCIDIACEA 2 iy)

Fic. 47, Distapha tokiuka nap. (paratype QM GH4179); a, colony: b. 7oaid. Distaplia violetta nap. (holotype
QM GH1358): ¢, colony; d. zooid: e. larva, Scales; a, Smin; bye, 0.5mm; ¢, 4mm; d, 0.5mm,

i132

present in January or June. The length of neck
of the brood pouch is variable. Sometimes brood
pouches are near the base af the colony, suspended
from the posterior part of the thorax by long.
narrow necks,

The larval trunk is 1,6mm long. and the tail
is relatively short, reaching halfway around the
trunk. There is a well-formed ocellus and otolith.
The base of the stalk of each of the 3 adhesive
organs is expanded but ampullae are not deve-
loped. The hyaline cap on the axial cone is large.
conspicuous and appears detached. Two blasto-
zonids lic in the frethy looking larval test.

Remarks. This species is readily confused with
D. siylifera, Disiaplia violeita can be distinguished
by its less conspicuous and less numerous stomach
folds, longer larval trunk, occasionally more than
one embryo in the long-necked brood pouch, and
the plum colour of its liying colonies and their
dark and subsequently greenish colour in preser-
vative. The testis follicles of D. stvlifera are usually
{but not always) smaller and more numerous. The
specimens with parastigmatic yessels and several
long embryos in the brood pouch assigned to D.
silifera by Millar (1975) may be of this species.

Living colonies resemble those of D. cuscina
n.sp, but have more conspicuagus cloacal apertures,
and vooids are readily distinguished by the
posterior abdomen of D. violetia.

Zooids resemble those of D. tokioka nsp. from
South Australia, although the upright, Nat-topped
colonies of the present species are distinctive and
its zooids have fewer and larger male follicles and
more stigmata,

Distaplia viridis Kott, 1957
(Fig, 48, Plate 10a-c)

Disiaplia viridis Kot, 1957a, p. 96; 19724, p. 7 (part.
specimens from Port Noarlunga. fig. 7). Millar, 19%66a,
p. 365.

Not Distaplia viridis: Kolt (972a, p. 7 (part, fig. 6
specimens from Hallett Cove < Disraplia pallida np)

DISTRIBUTION

New Reeorns South Australia (Great Australian
Bight, SAM E2040. QM GH4146 GH4tS9: Spencer
Gulf. QM GH4216). Victoria (Portland, QM GH45).
Queensland (Heron 1. QM GH4385),

Previousty Recorpen: South Australia (Spencer
Gulf — ¥2069 Kort 1957a; St Vincent Gulf — AM Y1182
¥2070 Kott 1957a. SAM 1239 Kott 1972a). Victoria
(Port Phillip Bay — Millar 1966).

The species appears indigenous most often taken from
the coastal area between Spencer Gulf and Port Phillip
Bay down to &m- It is presumed the single record [rom
Heron |. represents the northern limit of its range.

MEMOIRS OF THE QUEENSLAND MUSEUM

DESCRIPTION

ExternAr ApprArRAnce: Colonies are tlat
cushions up to lem in thickness with the zooids
opening only on the flat top of the colony. Zooids
are arranged in circular systems of up to 10 around
a central conspicuous and protruding cloacal
aperture. In preserved material ihe surface test
is slightly depressed over these systems, which are
about 4mm in diameter. Living specimens have
been described as brown and white, blue-black
with white markings, whitish with purple pigment
around systems, and blue-grey reticulate pattern,
the latter created by darker pigment around the
circular systems. In preservative colonies are
usually cream with a greenish tinge, although some
dark bluish pigment granules are sometimes in
the relatively thin test over the systems. The colony
from Heron I. is greenish blue over the systems
and dark blue between them, although the colour

Pic 48, Distaplia viridis, a, adult zoaid (QM GH45);
b, vegetative zovid with precocious gonads (QM
GH45), ¢, larva (AM Y¥1t182). Scales: a-c, 0.5mm,

THE AUSTRALIAN ASCIDIACEA 2

recorded for the living specimen was ‘black with
white markings’ — different from other species
eecurring at this location, and the same as the
South Australian specimens.

InvvRNAL Siraveruee Zooids are nol mare
than 2mm long, the thorax and the abdomen of
equal length. A vascular appendage extends from
the posterior end of the abdomen, but there is
no posterior abdominal sac. The terminal
branchial aperture has only small lobes, The upper
border of the atrial aperture is produced into a
long lip, usually with 2 or 3 small projections at
the tip. About 40 fine longitudinal muscles on the
thorax extend across the mid-line between the
apertures. The most dorsal muscles curve out into
the long atrial lip, others radiate lrom the
branchial aperture, and the most ventral muscles
(about half of the total number) eatend obliquely
across rom the endostyle to the posterior end ol
the thorax. Moscles are inconspicuous on the
abdomen.

The right side of the branchial sac has 18
stigmata in cach of the 3 anterior rows and l6
in the posterior row, on the left 20 and 18
respectively. Parastigmatic vessels are present, The
oesophagus is long and narrow, the orange
stomach in the pusterior third af the abdomen
is vertically oriented and slightly kidney-shaped,
It has fine reticulations on the surface but no ridges
or folds. There are no other apparent subdivisions
of the gut. A long oval gastric reservoir is in the
gut logp, about halfway along the gastro-intestinal
duct that connects the proximal part of the
intestine With the middle of the stomach, Gonads
are in the gut loop. The species is protandrous.
Even small, non-functional, vegetatively produced
yooids have large maturing testis follicles on the
right side of the gut loop. These small vegetatively
produced vooids also have a small ovum projecting
from the body wal] in the middle of the tests.
The testis consists of a cirele or hemisphere of
pear-to club-shaped follicles converging to the
proximal end of the vas deferens in the centre
of the circle.

Colonies collected from Spencer Gull (Kott
1957a) in December have a single large embryo
in the brood pouch attached to the postero-dorsal
corner of the thorax by a narrow neck, Colonies
collected in July from Portland (QM GH45)
contain vegetatively produced zooids with
muturing testes in both juvenile replicates and
adult zooids: Mature eggs and embryos are present
in colonies collected from St Vineent Gulf in
Noyember (AM Y1182 Katt 1957a),

Larvae dre large, with a loug cylindrical trunk
15mm in length and a relatively shore tail about

133

the same length. In mature larvae cach relatively
narrow stalk of the triradially arranged adhesive
organs has at least 2 swollen, balloon-like
ampullae at its base, Euch epidermal concavity.
With its cone of adhesive cells in the centre, 1
rather wide and shallow,

Remarks: The sheet-like colonies of Distuplia
pallida osp. can be confused with those of the
present species, However D. viridis has thicker
colonies, smaller more consistently circular
systems of zooids, more numerous branchial
stigmata, and a straight, vertical (rather than bent)
gut loop, Further, the stomach of 2D. pallid is
short and folded while that of the present species
lacks folds, In fact, the species that resembles the
present one more closely is D. retinaculate which.
although its colony i completely different, has
a similar number of stigmata, circular systems,
and the stomach Wall smooth externally and with
reliculations internally. Diytuplia florida nesp. i
distinguished from D, viridis by its eushion-hke
volony, its paler pigmentation, its very much larger
larva with # more elaborate adhesive apparatus,
and its more numerous stigmata, Distaplid cur ina
mp. also resembles. the present species haying
circular systems, & simular number ol stigmata,
similar gonads. and similar small zooids with
longitudinal and oblique muscles. The mternal
ridges in the stomach and more numerous muscle
bands distinguish it from the present species,

Genus Hypsistozoa Brewin, 1956b

‘Lype species: Désteplia fasmeriana Michuelsen.
1924

The penus contains species closely related
morphologically to those of Distaplia. Colomes
have a zooid-bearing head on ashort, fleshy stalk.
Zooids ure arranged im cloacal systems. [te
branchial apertures are 6-lobed, The atrial
apertures ure wide exposing much of the branchial
sac 10 the cloacal cavities, and they have a large
anterior lip. There are 4 rows of long, rectangular
slizmala, each row crossed by x fine puragtigmatic
vessel, The abdomen is short, and there is @ large
gastric reservotr inthe loop of the gut. and 4 rectal
valve at the proximal end of the rectum. Gonads
are posterior to the gut loop in the top of the
conspicuous vascular stolow. Fine longitudinal
muscle fibres extend onto and along the vascular
stolon. One or 2 embryos develop ina brood pouch
connected to the dorsal border of the thoraa just
behind the atrial aperture, near the terminal part
of the rectum, In both Mypsistozoa fesmeriana
and H. edistamaides the vas deferens curves
postertorly belore extendiug duteriorly to tte atrial

134

cavity, as in some species of Distaplia (D.
retinaculata, D. stylifera). Brewin (1959) has
described the prolific larval blastogenesis in the
type species. Unfortunately mature larvae are not
available in any of the known colonies of H.
distomoides and this cannot yet be confirmed as
a character of the genus.

The genus is separated from Distaplia by the
position of the gonads, and by the well developed
vascular stolon with conspicuous muscle fibres
extending along it.

In addition to the type species (which is known
from New Zealand) and H. distomoides, only one
other species of this genus is known — Hypsis-
tozoa obscura Kott, 1969 from the Peru-Chile
Trench. Otherwise the genus appears confined to
southern temperate waters.

Hypsistozoa distomoides (Herdman, 1899)
(Fig. 49. Plate 10d—h)
Amaroucium distomoides Herdman, 1899, p. 72.
Aplidium distomoides: Kott, 1957a, p. 95.
Distaplia distomoides: Kott 1972b, p. 170; 1972d, p. 243.

&
*

He
es

FA &

MEMOIRS OF THE QUEENSLAND MUSEUM

Dis TRIBUTION

New Recorps: South Australia (Great Australian
Bight, QM GH969 GH1280 GH1294 GH2390 GH4178;
Ward I., QM GH1297; Spencer Gulf, GH4182; Yorke
Peninsula, SAM E1987; Cape Jervis, QM GH114). New
South Wales (Jervis Bay, QM G10044 GH52; Port
Kembla, QM G9265 GH2004).

Previousty Recorpep: South Australia (Great
Australian Bight — SAM E1994-6 Kott 1972b). New
South Wales (Port Jackson Herdman 1899, Kott
1972d).

It is a temperate species, and is taken down to 20m.
At present it has a discontinuous range, with a gap
between its South Australian and New South Wales
records.

DESCRIPTION

ExrerNAL APPEARANCE: Colonies consist of a
long oval head, up to 4cm long and 3cm in
diameter, tapering to a short fleshy stalk. Zooids
are arranged in rather crowded circular to long
systems of up to 20 zooids. The test is soft and

I

Fic. 49, Hypsistozva distomoides: a, colony (QM GH114); b,c, zooids (QM GHI14 G9265). Scales: a, 5mm;

b,c, 0.5mm.

THE AUSTRALIAN ASCIDIACEA 2 138

i+ only slightly translucent in preservative. Living
colonies are reportedly rusty brown, orange, pink-
purple or brilliant purple.

Inregnal, Srevuecrurr: Zooids are relatively
small, the contracted thorax and abdomen
(including the gonad) together being only 2mm
long. The posterior abdominal vascular appendage
is relatively wide with conspicuous muscle fibres
extending along it. About 16 longitudinal and
oblique muscles are on the thorax, the dorsal ones
curving out into the large, rounded, anterior lip
of the atrial aperture. Six small lobes are around
the branchial aperture which is on a siphon with
a well developed sphincter. There are 10 and {2
sligmata respectively in the posterior and 3
unterior rows on each side of the body. Each row
is crossed by a parastigmatic vessel,

The oesophagus bends ventrally at right angles
{0 its vertical proximal part to enter the stomuch
about one third of the way down the abdomen.
the stomach is short and barrel-shaped with &
distinct rounded folds that tend to flauen toward
the pyloric end where the stomach tapers slightly
to the mid-intestine. ‘The mid-intestine is only
short, opening directly into the reetum about two-
thirds of the Way down the abdomen. A distinct
rectal valve is at the junction of the mid-intestine
and the rectum. A large gastric reservoir is present
in the loop of the gut — which is wide owing
to the horizontal orientation of the stomach,

Heart and pericardium are in the posterior end
ol the abdomen to the left of the pole of the gut
loop.

Gonads ure in the top of the vascular process,
just behind, and sometimes slightly overlapping.
the right side of the pole of the gut loop. They
consist Of about 20 relatively short, pear-shaped
follicles, their narrow ends projecting into the
centre to join the vas deferens, which curves
posteriorly and then dorsally before extending
anteriorly lo the atrial cavity, In zooids collected
from Port Kembla in September and October one
ur 2embcyos ure in a narrow-neeked brood pouch
attached to the dorsal border of the thorax just
behind the atrial opening, In one colony (QM
G9265) these embryos are tailed, and the trunks
ol the best developed are about Imm long. They
have an ocellus and an otolith in their cerebral
vesicles. howeyer no other organs can be seen.
‘The narrow neck of the brood pouches is often
long, the pouch projecting well behind the zooid
into the centre of the colony. Colomes collected
in March, April and May from South Australian
localities contained maturing testes. but no
developing embryos. The heart and pericardium

are in the posterior end of the abdomen to the
left of the pole of the gut loop,
Remarks: The species is distinguished trom H.

fasmeriana by the relatively few and wide stomach

folds. Despite the fact that this species belongs
to a different genus, its zooids resemble those ol
the South Australian species Disraplia pallida
nmsp.. in which the stomach has the same
horizontal urientation, and similar, although more
numerous, stomach folds,

Genus Neadistoma n.gen.
‘Type species’ Neodistonrd mammillatum nsp.

rhis monotypic genus is characterised by. its
Distaplia-like zooids with a large atrial apertuce
and a lip trom ats upper border, parastigmiatic
vessels, a distinct rectal valve. a large gastric
reservoir, and a conspicuous vascular process. The
characters by which it is distinguished from
Distaplia ave its barrel-like (rather than kidney-
shaped or oval) and distinctly folded stomach, and
the 6 or more (rather than 4) rows of stigmata.
There are no conspicuous muscles on the vascular
appendage as there are in Mypsistozoa.

Mostol the chdricters are common toall species
of Distaplia, and the reetal valve is knows in 0.
sivifera, D. retinaculaia nasp. and D. prolifera
msp., and in ¢/ypsistezea spp. The presence of
more than 4 rows of stigmata is unique in the
Holozoidac, The genus is known only from South
Australia,

Neodistoma mammillatum n.sp,
(Fig. 50. Plate | la,b)

Dis ie ton

Typr Loestiry, South Austratia (Seacliff St Vineet
Grill, low limestone reel, On top of rocks, 12m, coll.
N. Holmes 23.10.82, holotype SAM E1984 GM GH 104,
Flinders 1, lnvestizator Greup, in caves, under rovks,
Si, call, N. Holmes 10.4.83, paratype, OM GH2424,

Discretion

EXTERNAL APPEARANCE, Colonies form wide,
[lat cushions. up to 4em in diameter. The upper
surface is uneven, with 3 to 5 or more shallow
conical promineneces up to fem high, each with
a large terminal cloacal aperture. Zoaids are in
long double rows, one row each side of the canals
that radiate from the terminal cloaea! apertures.
A mass of vascular processes from the vooids is
in the central test of the colony. The test is soft
und gelatinous. In preservative ii is colourless jnd
translucent. Living colonies are yellawish.

Inte RNAL Stktcrure; Zooids are about 4mm
long and crowded vertically in the test, The

136

MEMOIRS OF THE QUEENSLAND MUSEUM

w
Fic. 50, Neodistoma mammillatum agen. nsp.: a, colony (holotype SAM E1984); b,c, zooids (holotype SAM
E1984, paratype QM GH2424). Scales: a, 5mm; b,c, 0.5mm.

branchial aperture has 6 wide lobes. The atrial
aperture is. a wide, asymmetrical opening, exposing
the dorsal part of the branchial sac, Its asymmetry
is related to the position of the zooid in relation
to the cloacal canal, A large anterior lip projects
from the upper border of the opening, About 20
fine longitudinal and oblique muscles are on the
thorax, including dorsal muscles that extend out
into the anterior atrial lip. The thorax is relatively
long, With at least 6 rows each of 6 stigmata. The
parastigmatic vessels bisect the stigmata in each
row, to form additional rows. Following the
horizontal division of each row of stigmata, new
parastigmatic vessels develop across each of the
new rows. Length of the stigmata varies greatly
in cach successive row. Small dorsal languets are
on the parastigmatic vessels, alternating with the
larger processes on the primary transverse vessels.

The abdomen is only about one-third of the
length of the thorax. The oesophagus ts narrow,
and is either vertical, opening into a vertical
stomach about halfway down the abdomen, or
it is bent ventrally to open into a horizontally
oviented stomach. The stomach is short, barrel-
shaped, and has about 12 distinct, wide longitud-
inal folds. The mid-intestine is. narrow, opening
into the rectum at the posterior end of the
descending limb of the gut loop. A conspicuous
rectal valve is present. A large gastric reservoir
is in the gut loop. Gonads are not mature in these
specimens, and only occasionally is a small ovum
found projecting from the body wall in the gut
loop.

There always are numerous non-functional
replicates scattered amongst the functional adult
zooids.

THE AUSTRALIAN ASCIDIACEA 2 137

Rimarks: In addition to the unusually large
number of rows of stigmata, this species can be
distinguished by its well-formed stomach folds and
the small number of stigmata im each row,
Additional sampling is needed to acquire spec-
tmens in which gonads and larvae are mature

Genus Sycozoa Lesson, 1830
Uype species; Syeazou sigillinoides Lesson, 1830

The genus is characterised by its regular, highly
organised and always stalked colamies in which
the zooids are in double rows along each side of
vertical cloacal canals that extend, parallel to one
another, down the sides of the head of the colony.
‘The stalk is Sometimes short, thick and fleshy as
in Distaplia, but in several species of Syvcozo@ the
stalk is long, thin, hard and leathery. l.obes around
the branchial apertures are reduced and usually
absent altogether. The body musculature is
reduced, Apart from some fine bands around cach
aperture, the body Wall has only 4 few (not more
than 5) fine muscles on the thorax, none on the
abdomen. Parastigmatic vessels are never present,
and the 4 rows of stigmata are in two piirs in
which the adjacent ends of the stigmata of each
pair-partner line up along cach side of the
transverse vessel that separates them. At their
opposite ends the stigmata progressively reduce
in length toward the endostyle, leaving a large
triangle of Unpertorated pharyngeal wall between
the ventral ends of the second and third rows of
stigmata. There is also an area of unperforated
pharyngeal wall both anterior and posterior to
the perforated séction, The atrial cavity extends
only Over the stigmata, not over the unperforated
parts of the pharyngeal wall consequently the
ventral part of the cavity is separated into twa
pouches by the triangular area between the ventral
ends of the second and third rows of stigmata.
The stomach is smooth walled and pear-shaped
lt opens into a Short duodenal area that is only
slightly smaller in diameter than the distal part
of the gut, With which it forms a sniooth cylindrical
tube without subdivisions, A small gastric
reservoir is present in S, verebriformiy and
eccasionally in §. sigi/lineiedes, but not in other
species. Gonads are either in the gut logp, or spill
out behind it, or are contained in a sac protruding
from the side of or behind the abdomen but never
much constricted from it. A broad pouch trom
the postero-dorsal corner of the thorax sometimes
is long and curved at its distal end. I contains
up to 40 developing embryos, the largest numbers
being in Antaretic species. Variable yumbers of
embryos are brooded, Usually colomes are

dioecious and aj) the heads of a compound colony
are of the one sex. However, with apparently long
periods when gonads are not developed, it is not
known whether a vuluny remains the same sex
throughout its life, Only in one species are there
mule and female zooids present at the same time
in one colony (8. anomala Millar, 1960). Larvac
are released from the top of the progressively
disintegrating head of the parent colony, which
sometimes, detached from its stalk, forms a large
floating brood sac.

Replication from isolated vegetative stalons in
the stalk of the colony is prolific, zooids being
added to the systems at the top of the stalk. Stalks
persist after disintegration of the heads and new
heads develop from the vegetative matenal stored
in the stalk (Caullery 1909; Salft 19253, 14926;
Millar (960).

Larvae ol Svcozeda have au large trunk, we'll
developed adult organs, and triradially arranged
adhesive organs, 2 dorsal and one ventral, each
with a large axial cone set in a deep epidermal
cup al the end of a smooth elliptical stalk, The
hyaline evp on the axial cone is often large. There
are no ectodermal ampullae and no frontal plate.
The ectoderm and text of the stalk of the adhesive
organs appears specialised in some species (see
S. puletira, S. brevicauda o.sp.) and may have
secretory cells and be adhesive, The ocelliny ss
absent. Larval budding in. Syeazea, as in Distaplia.
is never as prolific as it is in Arpsistozed, wor
do the buds develop to blastozooids as they de
in the latter genus, However in some species of
Syeozuu (8. pulehra and S. brevicauda in. sp),
the vegetative stolon (the left epicardial sac)
long and conspicuous and persists in the larval
trunk alter the buds have formed.

The form of the systems does vary. Usually each
long canal has a single opening. the openings
urranged wround the margin of the free end
the head. There they open either directly to the
exterior, or into a terminal cloacal cavity with
avenutral apical opening. Unlike Disraplia the rows
ol woods never converge onto the upper surlace
of the head, In a few species canals expand inte
the centre of the head, becoming confluent with
one another, and creating a large internal cavily
that opens by a single terminal aperture as in
Cvathacormus Oka, 1912. The latter genus was
erected to uccommodiute a species (C. mirahilix)
in whiely the double rows of zoojds typical of
Sycozow are embedded in the cylindrical walls of
a stalked, cup-shaped colony and project inte the
central cavity in parallel longitudinal ridges of test.
The atoyl apertures open directly into the central
cavity in the long furrows between the double raws

MEMOIRS OF THE QUEENSLAND MUSEUM

138

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THE AUSTRALIAN ASCIDIACEA 2

of vooids. Speozed cavernosa n. sp. from Western
Australia has such a cloacal system. In smaller
colonies the head is cup shaped as in the Japanese
species. In larger colonies the vpper third of the
head has an identical open cloacal cavity, although
in the middle third of the bead there is a central
core of Lest connected to the outer zooid-beuring
layer by horizontal radial test connectives. The
lower part of the head, where new replicates are
being added to the system, is sold, Further up,
the backward expansion of the cloacal cavity tends
to partially separate the central test from the outer
eooid-besring layer. This elaboration olf the
cloacal cavity does not justify the separation of
the genus Craphecormus from Syeosou, and the
genera are treated here as synonyms,

The homologue of the large internal cloacal
cavity of S. cavernosa can be obseryed m some
specimens of S. sigiflinaides when the terminal
cloacal cavity enlarges asthe top of the head begins
to disintegrate (releasing its larvae), The atrial
openings of the zooids are thus exposed directly
lo the central cavity,

In species with separate openings of cloacal
canals around the margin of the upper surface
of the head, disintegration of the terminal central
test sometimes leaves a concavity that can be
mistaken fora cloacal cavity with a wide terminal
opening.

Difficulties in interpreting the exact location of
cloacal apertures that arise from the disintegration
of the top of the head were observed by Michaclsen
(1924), and Millar (1960), Their location is also
obscured by the fact that they become large,
extending down the sides of the colony in a deep
VY. and exposing the cloucal canals with the atrial
apertures of the zooids directly to the exterior.

Since headless stalks persist, and the isolated
vegetative stolons contained in them subsequently
produce new zooids and regenerate new heads,
the colonies are probably long-lived. Much of the
vartability observed probably is caused by growth,
this being rapid resulting from prolific replication
of zooids. The presence of numbers of heads trom
u single base probably results from growth
following regression of a single head (Millar (960)
und ig not necessarily indicative ol a genetic
difference from individuals with single heads and
unbranched stalks. (here is little intraspecific
variation either in the numbers of stigmata in each
row, or in the shape and texture of the head and
the stalk, arin the numbers-ol testis follicles. Thus
it is these characters that must be used to
distinguish the species, for the shape of the
stamuch. the condition of ity wall and the course

139

of the gut are all remarkably constant throughout
the genus.

The genus is velatively diverse in Australian
waters where & of the [4 Known species have been
recorded, The Australian records comprise 5
indigenous species. two tropical West Pacific
species (§. seiziwadai and S§. pulchra) and one
Antarctic species (S. sigi/linoides).

The Antarctic members of the genus have wide
geographic ranges. Their larvae lack an ocellus
that would attract them into shaded settlement
sets, and in any case shaded places seldom vecur
in their open sea Floor habitats. Accordingly, their
settlement sites are not restricted, and this may
contribute to gene Mow (Berrill 1955). The genus
appears to have Antarctic affinities, Sveozoa
Kanzas! from Japan, is the only species that
extends north of the tropical western Pacific; and
although the two known Antarctic species, 3.
sig#linoides and S$. georgiana (see Millar 1960,
and Kou 1969) have a wide circumpolar range
in the Southern Ocean, the genus has not otherwise
been recorded from the AUantic Ocean. The
western Pacili¢ tropical species and Australian
temperate species have clear affinities with the
fauna of the Southern Ocean, viz. §. setzivindai
with the South African §. arharexeenx, and §.
pulchra, S, pedunculata and S. brevicauda n.sp,
with §. sivilinoides. The Australian continent
appears to have served as a bridge between
Antaretie and tropical Waters for radiation of this
genus

Key to Spreies of THE Genus Sycozea
Reoorbbi PROM AUSLMALLA

1. Cloacal aperture single, in centre of free end
0) (Tt: ne a =
Cloacal apertures numerous around outer
margin of free end of head i............3
Zooids embedded in longitudinal ridges
projecting into a central cloacal cavity;
gonads posterior to the gut loop .....-..-
bee teen e ee ee SPCAZOM CUVEFTOSE I. Spr,
Zooids ool embedded in longitudinal ridges
projecting into central cloacal cavity; gonads
al the side of the gut loop..... 02... 22...
Sycozad sigillinoigtes
3. Base of stalk with roat- “like hairs....,. cd
Base of stalk without root-like hairs .......5
4. Papilla present on body wall over pyloric end
of stomach .........20-- Sveezea pulehra
Papilla nat present on body wall over pyloric
end of stomach .. Spcosed brevicauda n.sp,
5 Zooul hearmy part of colony pleated .......
weve ere eee sees ee VCOZON Cerebriformts
Zooid bearing part of colony not pleated ...6

tw

140

6. Stalk thin and leathery, and very much longer
than head .......... Sycozoa pedunculata
Stalk not thin and leathery, and not very much

longer than head............00--ee eee 7

7. Stalks branch; test not firm and darkly
pigmented ............ Sycozoa seiziwadai
Stalks do not branch; test firm and darkly
pigmented .............. Sycozoa murrayi

The species known from adjacent areas are:

Sycozoa anomala Millar, 1960 (see also Millar
1982) from New Zealand has its gonads in
a posterior abdominal sac (as in S. cavernosa
n.sp.), a terminal common cloaca, narrow
rather than fleshy stalks, small branchial lobes
and occasionally hermaphroditic colonies.

Sycozoa arborescens Hartmeyer, 1912 from
South Africa has colonies with fleshy
branching stalks that resemble those of S.
seiziwadai (see Michaelsen 1923, Millar
1963a). However each zooid-bearing head has
a terminal cloacal cavity with a central
aperture rather than separate openings
around the head.

Sycozoa gaimardi (Herdman, 1886), known
only from the Magellanic region (see Kott
1969) has dome-shaped heads on slender
stalks.

Sycozoa georgiana (Michaelsen, 1907) a
circumpolar Antarctic species has a more
restricted range than S. sigillinoides, not
extending north of the Antarctic convergence.
Its main characteristic is the short zooid rows
resembling those of some specimens of S.
seiziwadae, however it has the single cloacal
aperture and narrow stalk of S. sigillinoides.

Sycozoa kanzasi (Oka, 1930) from Sagami Bay,
Japan, resembles S. pulchra in the presence
of a knob over the stomach, a narrow stalk
and basal roots. It is distinguished by its single
terminal cloacal aperture (Tokioka 1953,
Millar 1975)

Sycozoa mirabilis (Oka, 1912) from Sagami Bay
is distinguished from S. cavernosa n, sp. by
its cup-shaped rather than cone-shaped
colony, fewer zooids per vertical row, and
the much shorter and fleshier stalk supporting
the zooid bearing head.

Sycozoa brevicauda n.sp.
(Fig. 51)

DistRiBUTION

Type Locatity: Western Australia (Cockburn Sound,
coll. Western Australian Naturalist 28.5.58, holotype
WAM 139.75; off Eglinton Rocks, on floor of cave at
about 45m, coll. P. Roberts 22.12.75, paratypes WAM
801.83; 71 nautical miles N. of Port Hedland, 81-2m

MEMOIRS OF THE QUEENSLAND MUSEUM

on sand, coll. L. Marsh and M. Begant, paratype WAM
1046.83).

FurtHer Recorps: Western Australian (Steep Point,
QM GH4364; Houtman’s Abrolhos, WAM 804-5.83).
South Australia (Grange, SAM E2011).

DESCRIPTION

EXTERNAL APPEARANCE: The colonies consist
of a flattened, fan-shaped head up to 3cm wide
at the widest point. The head is supported on a
long (up to 8cm) narrow stalk, sometimes several
arising from a common basal stalk that, tuber-
like, runs along the surface of the substrate. The
stalk is relatively hard, with a tough outer cuticle.
Zooids are in vertical double rows that radiate
out along the fan-shaped head. The lower half
of the fan contains non-functional vegetative
zooids from the vegetative stolons in the stalk
being added to the double-row systems. The upper,
wide part of the fan contains rows of up to 20
functional zooids. The long cloacal canals between
the double rows of zooids open around the zooid-
free, flat, narrow, arched terminal surface of the
head. The stalk narrows toward its base where
it terminates in a clump of hair-like roots that
have a mass of sand entangled in them. Sometimes
(apparently wherever it touches the substrate)
clumps of roots along the length of the stalk
provide supplementary points of attachment.

INTERNAL STRUCTURE: Zooids are about 2mm
long, the thorax and abdomen of about equal
length. Branchial lobes are absent and the atrial
aperture is the usual wide opening into the cloacal
canal. It is asymmetrical, the shape of the opening
dependent on the side of the cloacal canal on which
it is located. The branchial sac has 12 stigmata
in the anterior pair of rows and 10 in the posterior
rows. The stomach is comma-shaped, tapering to
the intestine. The intestine and rectum together
form a continuous cylindrical tube without any
divisions in it. The stomach is slightly obliquely
oriented. Gonads are contained in the gut loop,
projecting from the posterior end of the loop when
mature. Colonies are dioecious. Up to 9 long male
follicles lying parallel to one another in a barrel-
shaped clump are in a zooid from a male colony.
The vas deferens curves posteriorly from the outer
end of the clump of follicles before extending
anteriorly with the rectum.

Brood pouches containing an embryo and one
egg in the upper part of the head of specimens
collected from Port Hedland in October (WAM
1046.83) and in the holotype specimen collected
in May.

Larvae are relatively small, the trunk only
0.6mm long, with the tail barely reaching its
anterior end. There is an otolith but no ocellus.

THE AUSTRALIAN ASCIDIACEA 2 14]

veces PeRECOr
SCOT COs CEC ee
Lurenscery

G
Feertsrreter ess

Fic, 51, Syeozoa brevicauda n.sp.: a, colony (holotype WAM 139.75); b, zooid (holotype WAM 139.75); c, larva
(paratype WAM 1046.83); d, adhesive organ showing hyaline cap in ectodermal cup (paratype WAM 1046.83).
Scales: a, lcm; b, 0.5mm; e, 0.1mm; d, 0.05mm.

142

The left epicardial sac is long, narrow, and persists,
projecting anteriorly from the left side of the gut
loop to lie between the thick elliptical stalks of
the 3 triradially arranged adhesive organs. These
stalks diverge from one another and project from
the anterior end of the trunk, each surrounded
by a layer of test. Ectodermal cells of the stalks
have fine cilia-like extension through the test, and
these form terminal expansions at the surface.
Remarks: The species resembles S. pulchra in
the presence of a long, narrow stalk with clumps
of hair-like roots fixing to the sandy substrate.
However, the head of the present species is wide
and flat, the head of §. pulchra being cylindrical
in section and more like an inverted cone. There
are slightly fewer stigmata per row, and 9 (rather
than 6) male follicles in the present species. The
projection from the body wall over the pyloric

MEMOIRS OF THE QUEENSLAND MUSEUM

end of the stomach, characteristic of S. pulchra,
does not occur in the present species. Larvae are
also similar, with a long epicardial tube, deep
adhesive organs, and unusual ectodermal cells on
their stalks. However the larval trunk of the
present species is about half the length of that
of S. pulchra.

Sycozoa cavernosa n.sp.
(Fig. 52)
DistRIBUTION

Type Locatiry: Western Australia (off Whitford
Beach, Cockburn Sound, reef 5m, coll. L. Marsh 16.2.79,
holotype WAM 795.83 QM GH2106, off Whitford
Beach, 3-4m, coll. L. Marsh 16.11.79, paratypes WAM
879.83; Woodmans Point, Cockburn Sound, coll. A.
Brearley 31.12.74, paratype WAM 199.75).

FurrHer Recorps: Western Australia (Dampier
Archipelago, WAM 1000.83; Cockburn Sound, WAM
219-20.73 805.83 807.83, QM G9653).

goandomponn
1 Wy Kag
Y

Fic. 52, Sycozoa cavernosa n.sp.: a, mature colony (holotype WAM 795.83); b, young colony (WAM 1000.83);
c, diagram of interior of the head; d, juvenile zooid with precocious gonads (paratype WAM 879.83); e,f,
female zooids (paratype WAM 199.75 1000.83); g, male zooid (holotype WAM 795,83). Scales: a, lcm; b,

2mm; d, Imm; e,f, 0.5mm.

THE AUSTRALIAN ASCIDIACEA 2

Nhe species has been taken dows lo TB iy, (tl has nal
been taken Outside Covkhurn Sound.

DeseRIPTION

Extervar Arrbananct; Colonies are conical.
pointed heads up to 7om long and 3em diameter
at their base, on more or less cylindrical stalks
about lcm in diameter narrowing slightly toward
the base usually about the same length as the head,
but occasionally longer. Basally each stalk breaks
into short hair-like projections which, when
entangled with sand, create a small and more or
less spherical holdfast. A large cloacal cavity in
the lop of the head has a large terminal opening.
Zooids are in the outer layer of test, arranged
in double rows extending down the sides of the
head of the colony. Double rows of zooids are
embedded in longitudinal ridges of test that project
into the internal cavity. In the lower part of the
head the terminal cavity continues down separ-
aling the outer zooid-bearing test from a central
core continuous with the stalk. The outer zooid-
bearing layer is joined to the central core by radial
connectives, which are strands of test about 3mm
in diameter that extend horizontally from the
central text core und cross the cloacal cavity to
join the zooid-hearing ridges of test. Vascular
appendages of the zooids extend through these
cannectives, into the inner core and thus down
into the stalk. Atrial apertures of zooids open
directly into the cloacal cavity between the
projecting zovid-bearing longitudinal ridges,
Capacious cloacal spaces in the heads of mature
colonies cause heads to be flaccid in preservative.
Colonies in which vegetatively produced 7a0ids
are maturing have less extensive cloacal spaces
and are firmer, while in one small colony the centre
of the head is an open cloacal space without any
central test core (WAM 1000.83), The colour of
living colonies is not known, In preservative they
are beive with prey zooids.

INTERNAL STRUCTURE, Zooids orient obliquely
in the colony with their atrial apertures uppermost
(Opening into the adjacent cloacal canal), with
their ubdomina und posterior abdominal sacs
projecting into the radial test connectives. Thorax
und abdomen together are up to 2mm long. The
posterior abdominal sac iy about half that length
only when the male gonad is mature, The small
branchial aperture is not lobed. The atrial aperture
is large. the sides of the aperture being drawn back
to expose most of the branehia) sac to the cloacal
cavity. The upper border of the opening ts
produced into a rounded lip. Fine musele bands
are in the thoracic body wall, but are inconspic-
uous and not numerous, There are 12 long

143

rectangular stigmata in the 2 anterior rows and
LO in the 2 posterior rows.

The pear-shaped, smooth-Walled stomach,
tapering to its pylone end, 1s hallway down the
abdomen, No other divisions of the gut were
observed,

Gonads occupy the narrow-necked sac behind
the abdomen, Male and female gonads are never
present together, and all the zooids in the colony
are of one sex. Mature testis follicles (5) are in
paratype material collected in November (WAM
879.83). Mature ova (3 to 5) are in a colony
collected in December (WAM 199,75) and in this
colony up to 3 early embryos are in a Jong breod
pouch with @ short, narrow peck connecting i
to the postero-dorsal corner of the thorax.
Colonies collected in September (WAM 219-
20.73) have only immature zooids, an incipient
posterior abdomen without contained gonads
being present, and in these colonies. the cloacal
cavities are More limited. In colonies taken in June
(WAM 805.83, 807.83) the head (s relatively firm.
there are no gonads, only a few cloacal spaces
and no cloacal aperture, and the vooids are
juveniles, embedded jn the test,

Apparently seXual reproduction oceurs at the
beginuing of summer (December) and larvae mity
be released in January and February. Thereafter
the zouids may regress, vegetative xooids reap-
pearing in June, developing through late winter
and Spring (August to November), Larvae of this
species are not known.

Remanks: The extensive internal cloacal cavity
with longitudinal ridges (containing embedded
zovids) projecting inte it, and the wide terminal
aperture, together with the smooth outer surface
of the colony readily distinguish it. (he head vf
the juvenile specimen (WAM 1000.83) resembles
S. mirabilis (Oka, 1912) although Oka’s specimens
were larger With a short fleshy stalk and appear
not to be canspecific with the present species
Gonads were not developed in S. mirabilis. Theie
presence im a posterior abdominal sac in {he
present species, as in some speeies of Distaplia,
resembles Sreezeaanomala Millar, 1960, however
Millar's species (from New Zealand), does not have
the open cloacal cavity of the present one.

Sycozoa cerebriformis (Quoy and Gaimard, 1834)
(Pig, 53, Plate Tle h)

Aplidie cerebriforme Quay and Gaimard, 1834, p. 62.

Syeozod cerebrifarnus; Brewin, 1953, p. 58. Kotl, 1957a,
p99, 19720, p, & 1972b, p, 170; 1976, p57 Millar
1963u, p. 708; 19660, p. 365,

Diviaplia verebriferme; Michaclsen, 1924, p, 325,

Colella plicuta Herdman 1899, 0)

Calella incerta Cuullery, 1909, pn WL

144 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic, 53, Sveozoa cerehriformis: a, young colony (QM G9637); b, zoo (SAM £2020); ¢, juvenile vegetative
zooid (SAM E2013): de, abdomens of male and female zooids (SAM E2021); f larva (QM GH2405). Scales:
a. lem; b-e, 0.5mm; f, 0.1mm.

THE AUSTRALIAN ASCIDIACEA 2

Disreietion

New Recombs: Western Austratia (Shark Bay, WAM

797,83; Houtman’s Abrolhos. WAM 805 6.83; Dongara.
WAM 1047-9.83; Cockburn Sound, WAM 159.74 21.75
24.75 87.75 94.75 131.75 209.75 219,82 7OK-BOO.B3 1043
4.83). South Australia (Great Australian Bight, SAM
£2001 E2011 F2014-5 F2021; Nuyts Archipelago, SAM
£2019-20 E2030, OM GH4214; Spencer Gulf, SAM
£2012 E2017 £2022 3 £2025 9 E2045; St Vincent Gulf,
SAM E1954-6 E1958 E2018 E2024. OM GH240S
GH4224; West 1. SAM £2013, OM G9264 GH2405).
Victoria (Gabo 1.. SAM £2016, AM Y2037; Bass Strait,
QM GI2735 GH2393 4. MV M462 H475 +929).
Tasmania (Swansea, 1M D93 D19l: Port Davey OM
GH1844). New South Wales (Buateman’s Bay, AM
Y2147: Jervis Bay, OM GLO0LS-6; Port Kembla, OM
69262, Port Stephens, AM Y2135) Monavale AM
Y2136; Port Jackson. AM Y278K: Nambucca Heads QM
GL0009; Solitary 1. QM G9637; Cook 1, QM GH4223).
Queensland (Moolaglabah., QM GLO107)
Rrcorpep, South Australia (Great
Austrulian Bight QM G9263 Kott 1972b; St Vincent
Gull — Kore )957a, 54M D268, OM G9Al7 Kou 1972a:
West 1, Wright 1, Kott 1972a). Victoria (Western
Port, Port Phillip Bay — Quoy and Geayard 1h34,
Caullery 1909, Kott 19574 (976, Millar 19634 19664).
New South Wales (Jervis Bay, Port Hacking, Port
Jackson, Port Stephens — Herdman 1899. Kolt 1957a,
Millar 1963a).

The colonies from Dongara and Shark Bay (WA) are
all small and these may represent populations al the
northern extremity of the range of this temperate
indigenous species. The specics ts Laken in caves. and
crevices off reefs, and dredged off the sea floor ut depths
down to 50m,

Prrviouscy

Deserip nos

EXTERNAL APPEARANCY: The colony consists
ula relatively short (usually not more than |5cm
long) fleshy (up to 3cm in diameter) stalk that
(lattens out at the top where it expands into a
flat, ribbon-like, yooid-hearing lamella up to 2em
high, Occasionally the stalk is longer (up to 7¢m)
and cylindrical, The top edge ol the z001d-bearing
lamella is flat and 2ooid-free. In young colonies
the lamella is merely [lat and spade-shaped. but
as the colony develops it increases in width, At
lirst it curves around at each end, ity junction with
the top of the head being horse-shoe shaped.
Subsequently it becomes long and is gathered and
pleated onto the top of the stalk, One colony (SAM
126%) bas a lamella that is 74cm wide, gathered
ento the top of a stalk of about 3cm diameter
w make a complex rosette Rem in diameter.
Sometimes the basal stalks branch, cach terminal
branch having an expanded zooid-hearing part
that usually fuses with that of its neighbour. A
thin layer of test sometimes connects the branches
of adjacent stalks.

143

Zooids are in parallel double-row systems down
each side of the flat lamellae. Each cloacal canal
Opens by a separate Jarge aperture al the top of
the canal, the apertures are around the margin
of the flat, narrow upper surtace of the lamella.
The double row systems seldom contain more than
§ functional zooids in cach row, These occupy
a band about lem wide along the upper part of
euch side. The lower lem has a band of non-
functional replicates progressively joining the
vertical rows of functional zooids, and, lower
down, just above the stalk, the basal stolons of
the adult zooids converge into the stalk. The
surface test is covered With minute, evenly spaced
inconspicuous pointed papillae

In life, specimens of this species with their tightly
pleated rosette-like colonies are Spectacular. A
range of colours is known, Collector's notes for
colonies taken from 25m off Mooloolaba (QM
GIO107) indicute they were yellow, but changed
to purple when damaged or removed from the
substrate. Specimens photographed in awitu are
blue, pink, red, orange, or yellow. In preservative
they are sometimes translucent blue, pink or
cream.

Intpenar Stevertier: Mature zooids are up
to 2.5mm long, delicate, with thoraces Collapsed
in preserved material, but never contracted
Muscles are around the apertures, bul only about
§ fine muscles extend from the branehial siphon
a short distance down each side of the pharynx.
There are 14 stigmata in the anterior pair of rows
and 13 in the posterior rows, Phe oesophagus is
fairly long. tbe small oval stomach slightly oblique,
the gut loop almost vertical, and w sinall spherical
gastric reservoir is in the gut loop,

Colones are dioecious. Gonads are on the mght
side of the gut loop. The ovary contains up to
3 ova, und the testis 4 or 5 wedge-shaped follicles
arranged in a tight circle. Short vasa ellerentis
fromeach follicle join the yas deferens in the centre
of the circle, The vas deferens then mnakes a short
loop posteriorly before extending anteriorly slong
the inside of the reetum.

The breeding season for this species appears
short, Colonies collected (rom South Australia
had mature male did female gonads in May (SAM
E2021), Embryos are in one colony taken in April
(SAM E2014) and one in May (QM GH2405),
Although gonads are sometimes presentin Match,
July and October. they are not mature. Gonads
were not present in any of the specimens collected
in January or February. Material was collected
from western Australian waters in all months
except January tind Vebruary. Most: sexually

146

mature colonies were males taken from October
ta December (WAM 94.75 802,83 131.75 798,83),
although one mature male colony was taken in
May. One colony with larvae and embryos was
taken from Cockburn Sound in December (WAM
799.83). In general, the species reproduces sexually
in Spring and autumn. The significance of the
preponderance of male colonies present in the
collections is not understoad,

In this species there is only one almost spherical
embryo jn cach brood pouch, The larval trunk
is 0.8 to Ldn long and the tail is wound one
and a half times around ut, There ts an otolith
hut no ocellus, and neither epicardial tube nor
buds have been detected. The adhesive organs are
large with tall. narrow axial cones and epidermal
cups. and short, thick stalks. Each adhesive organ
protrudes from the anterior end of the trunk
surrounded hy a Jayer of test.

Remarks: The flat, ribbon-like, pleated, zooid-
bearing part of the colony, together with the short
systems Containing less than 10 functional zooids
per row are distinctive characters, Further this ts
the only species of the genus in which a gastric
reservoir is always present, though S. sigillinoides
sometimes has one (Kott 1969),

Sveozoa brevicauda n. sp.. which also has a
flattened head, does not have the short rows of
vooids nor the ribbon-shaped head of the present
species (its head being fan-shaped); nor does. it
have the short fleshy stalk of the present species.

The species appears related most closely to the
tropical S. seiz/wada. which it resembles in having
branched fleshy stalks, short systems, relatively
few male follicles, a single larva in each brood
pouch, large larval adhesive cones and no
conspicuous epicardial tube extending lo the lront
of the larval trunk. Spveozva seiziwaeal is
distinguished from the present species by its
narrower zooid-bearing heads that are not pleated,
a lunger and narrower gut loop, the absence of
A gastric reservoir, and a smaller larva with a
shorter tail and larval buds.

Sycozoa murrayi (Herdman, 1886)
(Fig. 54. Plate 12a)
Colella murrayt Herdman, 1886, p, (15, var. rubida p,
119,
Syeorea murrayr, Kot, 1957a, p. 97.
Aveasna taxmanvides. Kott, 1954, p. 157.

Hse pias

New Reeorns South Australia (Great Australian
Bight. OM GH4155; St. Vincent Gulf, OM GH4220),
Tasmania (Midway Point. 1M DIIS87; northeastern
Tasmania, IM D1834),

MEMOIRS OF THE QUEENSLAND MUSEUM

Precviorsey Reeowoun Tasmania (off Maria |.
AM Y1231 Kott 1954). Victoria (Busy Strait Herdman
18846). New South Wales (off Port Jackson — var. rubida
Herdman 1886, Bermagui — Kott 1957a}.

The species appears indigenous and {emperite.
ranging from the Great Austrahan Bight to the vicinity
of Port Jackson.

Description

Exrernat Appearance: Colonies have a
flattened and paddle-shaped, or a smooth oyal,
stalked head. The newly recorded specimens have
heads 2em long, about lem wide across the middle
or widest part and only about @.5em_ thick.
Posteriorly the head tapers to the narrow firm,
short stalk that is never more than slightly longer
than the head and lacks an outer hard cuticle.
The stalk narrows toward the base and terminates
ina rather blunt point without breaking into either
roots or hairs, The lower part of the stalk adheres,
along its length, to the sustrate (weed stems,
fronds). Inspecimens recorded by Herdman (1886)
and Kott (1957a) the stalk is shorter and thicker.

The test is unusually firm, containing bluish-
black pigment particles present also in the body
wall of the zooids which are in vertical double
row systems, with the cloacal canals opening
around the upper margin of the head.

INTERNAL StRUCTURE; Zooids are of the usual
form, about 2mm jong with 12 to 14 stigmata
per row. The stomach is slightly obliquely
oriented. wide anteriorly and gradually decreasing
in diameter toward the pyloric end where it is
continuous with the intestine. There is no gastric
reservoir In any of the examined material, The
gut loop is vertical, The body wall has no papilla
over the pyloric end of the stomach. No gonads
occur in the newly recorded material. Male gonads
Were in the specimen from Bass Strait (Herdman
1886), They consist of ovate male follicles
(Herdman (886). In an oblique. almost longitud-
inal section 4 follicles are seen (Herdman 1886,
pl, 17, lig, 10), Specimens from the NSW coast
(Kot [957a) have mature ovaries, embryos and
tailed larvae.

The larva has a relatively short trunk 0.7mm
long. The 3 adhesive organs, triradially arranged,
are on unusually short, thick stalks. The axial cone
of adhesive cells with ils epidermal cup is
particularly large. The tail is long (more than 2mm)
and winds around the trunk nearly one and a half
times. There are no rudimentary buds in the larval
test and the epicardial tube was not detected.

Remarks: The unique characters of this species
ure its relatively firm and pigmented test. short
stalk that is much the same consistency as the
test of the zooid-bearing head, and the size of

THE AUSTRALIAN ASCIDIACEA 2

Fic. 54. Svewzoa murrayh: a. colony (GH 4155); b larva
(AM, off Berniagui), Scales: a, lem; b, 0.2mm.

the larva, The large axial cone of cells in the
adhesive organs resembles that of S. cerebriformis.
The head is sometimes flattened as in S. brevicauda
n. sp., but the stalk is shorter and lacks the terminal
hairs of the latter species, Syeozva murrayi is
distinguished trom S. pulchra and S. pedunculata
by its flattened head with firm test, and its shart
stalk.

Although the stalk was shorter and thicker than
in the newly recorded specimens, Herdman (1886)
recorded the characteristically firm pigmented test
and flattened colonies in describing this species.

Sycozoa pedunculata (Quoy and Gaimard, 1834)
(Fig. 55. Plate 12b)
Aplidie pedunculatum Quoy and Gaimard, 1834, p. 626.

147

Not Aplidium pedunculatum Cunningham 871, p. 490
(< Sveozoa sigillinoiedes).

Colella pedunculata: Caullery, 1909, pp. 14. 30 (Specimen
from King George Sound),

Not Collela pedunculata Herdman |886, p, 74. Ptelfer,
1889, p. 4, 1890, p. 499. Sluiter. 1900, p. 5; 1906,
p. 6 (<= Syeozou sivillincides).

Not Sicozeq pedunculata: Koti, 1972b, p. 170; 1975,
p. 2; 1976, p. 45 (< Sveozod pulehra); Kott, 1972d,
p. 243 (< Sycozea seiziwadai).

? Syeozoa sivillinoides; Michavlsen, 1924, p, 505 (part,
specimens from Tasmania, Bass Strait, Western Port),
1930, p. 505 (part. specimens [rom Albany).

Dist Riat 110N
New Recukps: Victoria (Portsea, QM GI0120;

Western Port, AM Y214%; Bass Strait, MV H449, OM

G12747) Tasmania (Port Davey, OM GH2022 GH2025;

southern Tasmania, TM D708; southeastern Tasmania,

TM D2025; Huon Channel, TMD1858; cd Rntrecasteaux

Channel, [TM D276; Derwent Estuary, TM D103/579

D7tl D713 0721-2: northeastern Tasmania, “1M

DI835),

Priviousivy Recorora: Western Austraha (King
George Sound — Quoy and Gaimard 1834,’ Michaclsen
1924, 1930). Victoria (Bass Strait =? Michaelsen 1924;
Western Port — Quoy and Gaimard 1834. ? Michaclsen
1924), Tasmania — ? Michaelsen 1924),

DESCRIPTION

EXTERNAL APPEARANCE, Colonics have an
inverted conical zooid-bearing head (up to 2em
Jong) on a long (up to 9cm), hard stalk, The flat,
terminal zooid-free top of the head is from | to
l.6em in diameter, and is the widest part of the
head. Basally. the stalk breaks into short branches
that attach directly to a hard substrate. Up to
20 zooids in about 20 parallel, vertical double-
row systems are evenly spaced around the head.
The cloacal canals have wide openings around the
outside of the margin of the fat terminal surface
of the head. In one colony from Tasmania (TM
D708) 5 heads are at the top of the leathery stalk
of the colony.

In the specimen from Sandy Bay (1M D711).
the central test is withdrawn from the top of the
head, leaving zooids embedded in the outer layer
of test surrounding a terminal cavity and giving
the impression of a terminal common cloaca with
a large opening. However, this is an artefact. The
cloacal canals open around the outside of head
as is characteristic of the present species and not
into a terminal cavily as they do in S. cavernasa
n sp.

INTERNAL STRUCTURE: Zooids are relatively
large for this genus, from 3 to 4mm. The branchial
aperture is smooth. The atrial aperture has a wide
rounded upper lip. There are 19 or 20 stigmata
per row in one specimen (QM G10120), but other

148 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 55, Sycozoa pedunculata: a, whole colony (QM GH2022); b, head showing arrangement of systems (QM
G12747); e¢, male, contracted zooid (TM D708); d, larva (TM D711). Scales: a, lcm; b, 5mm; c, 0.5mm; d,
0.2mm.

THE AUSTRALIAN ASCIDIACEA 2

colonies have only 14 to [6 stigmata per row. The
smooth stomach as slightly obliquely oriented, I
is wide anteriorly, and posteriorly it tapers to the
intestine. Neither a constriction nor a valve is
between the (Intestine and the rectum, that part
of the gut distal to the stomach forming an even
cylindrical tube. No papilla is present on the body
wall over the pyloric end ol the stomach, Gonads
are enclosed in the gut loop.

The female gonad consists of a large (up to 7-
egg) ovary. The mature testis consists of 8 to 10
long follicles arranged in parallel to form a wide,
barrel-shaped clump that juts out from the side
of the gut loop. The vas deferens makes the usual
posterior loop from the distal extremity of the
testis before extending antenorly along the rectum,
Mature male gonads are present in colonies
collected in September and October from southern
Vasmania (TM D708 192025). In the Bass Strait
material one colony (QM G10120) is female with
large eggs in the ovary, however embryos are not
present. Embryos were in the type specimen (see
Caullery 1909, fig. 7, p. 17) and up to 7 embryos
are in a brood pouch in the newly recorded
material from Sandy Bay (TM D711).

Larvae are relatively small with an almost
spherical trunk 0.9mm long. Prom the newly
recorded colony TM D7I1, larvae from the one
brood pouch have tails of variable length, Some,
like those of 8. pudehira reach halfway around the
trunk. and others, like those figured by Caullery
(1909, fig. 7), reach almost the whole way around
the trunk, Neither epicardial tube nor rudimentary
buds were detected,

Remarks: Quoy and Gaimard (1834) described
Aplidle pedunculara trom Western Port (Victoria)
and King George Sound (Western Australia),
Subsequent authors, including Herdman (1886),
recognised it as a species of the genus Syeezod
(= Colella), but mistook specimens of the Antaretic
S. sigi/linoides Lesson, 1830 for Quoy and
Gaimard’s. species. Accordingly, for many veurs,
S. pedunculata was treated as a junior synonym
of §. yigillinoides. The type material of 8,
pedunculata, from King George Sound was
redeseribed by Caullery (1909), Although the
shape al the colony could cause it to be mistaken
for S. sigdlineides, larvae of the latter species have
au much longer tail.

The short tial (relative to the Jong ane of S§,
sivillinvides) led Kott (1972d) to regard S.
pedunculaia as conspecific with S, renuteayliy (=
S. pulchra). Syeazoa pedunculata is distinguished
from S. pulehra by its more numerous male
follicles. lack of root-like hairs on the base of the
stalk and absence of the abdominal papilla. The

149

newly recorded specimens from Bass Strait and
Taxmania appear the same species as redescribed
by Caullery (1909) from King George Sound.
Western Ausiralia.

Sycozoa pulehra (llerdmian, | 886)
(Fig. 56, Plate |2ed)

Colella pulchra Herdman L886, p. Wb; 1891, po All:
TROS, p 447

Syetcoa pulehra: Sluiter, 1909. p, 33. Not Van Sane
WIS. p, 142 (2 = Sveozwa serwvacdae),

Colella tenuicaulis Herdman 1899, p. 64,

Sveozoa tenuicaulis: Brewin, 1953. p. 57. Kath. (997a,
p. 99: }972—, p. & Millar, Mesa p. 707,

Sreozed pedunculata: Kote 19726, py (70. bY72c, p. 2M,
1976 p, 56, 1975, p. 2.,

? Sveecea sigilinoides: Michwelsen, 1940, p1 S05 tpn
specimens rom Fremint}e).

Ds bein plo

New Rpeowoss Western Australia (Dongarra, QM
G9476, WAM (001.83; Cockburn Sound WAM 9577
226,73 102,75 228.82 1002.83. OM G9633) bspernnee
WAM 68.75), South Australia (Spencer Gull. SAM
2032 2034-6 F2040 7; St Vincent Gull, OM GHT16,
SAM E2033: Kangaroo |.. QM G9999), Victoria (Buss
Strait, OM GI2745 MV H449; Western Port, MY
F53324 653335), Lasmania(southeastern tasmania, | M
D723 DIN72: d'Entrecasteaux Channel, VM 1251
D180) DL8S8; Roches Beach, TM D1020; Okehampton
Bay. IM DIKIS) Queensland (Moreton Bay, QM 4930)
G5140 $2; Townsville).

In Moreton Bay (7 Xm, Rous Channel), feeding trails
of Duveng dugen cul rough crowded populations
(about 2.000 heads per m*) of this species (A. Preen
pers. comin).

Previowsry Recornri: Western Australia ( Mallar
1963a\ ? Cockburn Sound Michaelsen 1930). South
Australia (Spencer Gulf — KRotr 1975, St Vincent Cnulf

Kott 1972a; Investigator Strait Kott 1972),
Victoria (Portland, Port Phillip Bay, Western Port Bay

Millar 19634, Kott 1976), New South Wales (Botany
Bay, Broken Bay. Jervis Bay. Port Stephens, Port
Jackson, Bermagal Herdman (899, Brewin 1953, Kolt
19574. Millur 19634), Qucensland (Moreton Bay — QM
G493) | Gola’ Y Kott 19720). North Australia (Torres
Suraut Herdman 186). Indonesia (Sluiter L909),

Discretion

Paarrenat Areraraner; Zomds ate in about
& pairs of double row systems extending parallel
to one another down the sides of vertical. oval
or inverted cone-shaped heads, with the terminal,
free ends cither Hattened or rounded. but always
Without zooids. Deep, V-shaped cloacal apertures
open around the side ol the upper margin ol the
head. The stalk is narrow and never is less than
4 times the length of the head, often much longer.
Asmall colony from South Australia, with a head
about L.Sem Jorg, hus a stalk of Sem (SAM
2047), while one from Kangaroo lL. (QM G#999)

150 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic, 56, Syeozoa pulehra: a, colony (SAM E2047): bye, juvenile and male zooids (SAM E2047): d, larva (QM
G9261); e, detail of larval adhesive organ showing stalked vesicles [rom epidermis of the adhesive organ stalks
(QM G9261). Seales: a, lem; b,c, 0.5mm: d, 0.2mm; e, 0.05mm.

has a head 5em long with a stalk of 28cm and sometimes tufts of hair occur also at other points
is the largest specimen known. A tuft of root- along its length. Often several stalked heads arise
like hairs always is at the base of the stalk, and froma horizontal basal stolon with clumps of hairs

THE AUSTRALIAN ASCIDIACEA 2

scattered along its length. One specimen (WAM
102.75) has a much-branched stalk, each branch
with a small, oval head, and the main stem from
which the branches arise has a tuft of roots at
its base. The stalk is hard with a hard outer cuticle,
but the test of the head is soft. Heads are often
found flattened in preservative, but this could be
an artefact of preservation resulting from their
softness.

Up to 50 functional zooids per row occur in
the longer heads, although some of the smaller
ones have less than half that number. At the base
of the head small replicates, progressively
becoming functional, are being added to the
systems from the vegetative stolons in the stalk.
Headless stalks are often collected (Spencer Gulf
SAM E2035-6 collected in November; Moreton
Bay QM G5178 collected in October).

Living colonies from Torres Strait were reported
as red (Herdman 1886), as are photographed
colonies in Cockburn Sound (QM G9633).
Specimens from New South Wales were reported
as ‘yellow, grey, slate, dark purple-brown and dull
pale purple’ (Brewin 1953, p. 57), however it is
not clear that these colours are found in living
specimens, although specimens from Moreton Bay
are blue. Photographed specimens from South
Australia are white to yellow with a red tinge.

INTERNAL Structure: Zooids without mature
gonads are only about 2mm long when the
abdomen, which is relatively small, is folded up
horizontally behind the thorax as it so often is,
even in the small vegetative zooids. The branchial
aperture has a smooth margin. The atrial aperture
is wide and asymmetrical, with a pronounced
upper lip. Muscles are fine, and present only
around the apertures. There are 16 stigmata in
the anterior pair of rows and 14 in the posterior
rows. The most conspicuous feature of all the
examined material of this species is the wide knob-
like papilla projecting from the body wall, just
above the pyloric end of the stomach.

The oesophagus usually makes a right-angled
bend before opening into the horizontally oriented
stomach, which is wide anteriorly and tapers to
its pyloric end before narrowing abruptly to the
intestine. The intestine with the rectum forms a
continuous cylindrical tube. Gonads are at the side
of the gut loop, projecting from it. Thus, when
the gut loop is horizontal, the mature gonads
project behind it. However, gonads do not project
behind the pole of the gut loop. The mature testis
contains 4 to 6 long follicles, parallel to one
another forming a barrel-shaped clump with its
longitudinal axis at right angles to the longitudinal
axis of the gut loop. The short vasa efferentia

151]

joining the male follicles to the vas deferens are
at the distal end of the follicles — the parietal
end distant from the gut loop. The vas deferens
makes the usual posterior loop before extending
anteriorly, down the length of the testis to the
rectum. The vas deferens and the rectum extend
together to the atrial cavity. Mature ovaries have
about 3 eggs.

In upper Spencer Gulf, heads have been
observed to detach from the stalks in early
summer, another head regenerating the next
winter (Shepherd 1983). However, this timetable
is not universal, for in other colonies from South
Australia gonads are mature in November (SAM
E2033) and January (SAM E2034 E2046-7); and
embryos occur in the last two specimen lots. In
the Tasmanian material embryos occur in July
(TM D1815) and December (TM D1172), and
maturing ova in October (TM D1803). In the
western Australian material mature gonads occur
in February (WAM 68.75) and November (WAM
1002.83). In Moreton Bay (Queensland), the
gonads are mature in July (QM G5150-2) and
September (QM G6148) and embryos occur in
April (QM G4930) and July (QM G5151). Thus
in South Australia sexual reproduction may occur
throughout the summer — from November to
February, the heads detaching from early summer
to autumn. The existence of sexually mature
colonies in April to September in Moreton Bay,
suggests a different pattern in the tropics.

From 2 to 8 embryos occur in the brood pouches
and half of these are either embryos at an early
stage of development or unfertilised eggs.

Larvae are large, the trunk being 1.2mm long.
However, the tail is short, wound only a little more
than halfway around the trunk, There is an otolith
but no ocellus in the cerebral vesicle. The branchial
sac is well developed, with 20 stigmata in the
anterior rows and [8 in the posterior rows — 4
more in each row than in the adult zooids. The
3 smooth, elliptical stalks of the adhesive organs
diverge from one another from the ventral part
of the thorax of the oozooid. They contain a
conspicuous internal extension of the larval
haemocoelic cavity, a layer of ectoderm and a thick
layer of test. Cilia-like extensions run through the
test from the ectodermal cells. These have small
terminal expansions at the outer surface of the
test. The axial cone of adhesive cells surrounded
by its ectodermal cup and topped with a large
hyaline cap is at the end of each stalk. A long
extension from the posterior end of the left side
of the abdomen — the left epicardial sac — extends
forward to lie amongst the stalks of the adhesive
organs, It is narrow proximally and expands

152

toward the anterior (distal end), There are 3
rudimentary buds lying in the larval test around
the base of this sac, which, presumably, continues
its development after the buds separate from it,

RemMArKS: The range of this species appears
continuous from Western Australia across the
temperate southern coast to Moreton Bay and
‘Townsville. Consequently there is no geographic
reason why §. tenuicaulis and §. pulchra (from
Torres Strait) should be considered distinct. The
basal stolon (uniting stalked heads) which
Herdman (1899) believed characteristic of S.
tenuicaulis occurs in temperate as well as tropical
populations. Further, the abdominal papilla from
the body wall over the pyloric end al the stomach,
which Herdman (1886) first reported for &.
pulchra, is present in all the examined specimens,
Tt appears a reliable taxonomic character support-
ing the synonymy of §. puleftra and §. renuicaulis.

A similar papilla is present in 8. kanzayi (Oka,
1930) from Sagami Bay, This species, although
apparently related, is separated from S. pulchra
by the presence of a single terminal cloacal
aperture (Tokioka 1953). The size differences
referred to by Tokioka (1953) and Millar (1975)
are not significant, but attributable to zooids and
colony of the type specimen of S. pulehva coming
from the lower end of the range for the species.

Toktoka (1953) believed the papilla in 8. kanzasi
an incipient bud, However there is no indication
of budding, In the examined specimens of §.
pulchra the structure seems a thickening of the
ectoderm that is inserted into the test. 1t muy be
this device that keeps the gut loop horizontal in
this species and in S. Aanzast.

Kot (1972¢) suggested that 3. sigillinaides:
Michaelsen 1930 trom Cockburn Sound is a
synonym of 8. pilehra (> $8. peedunculata: Kote
1972c). This is probable. Syeazea pulchra, but not
S, peduneulata, is common in Cockburn Sound
(sce New Records, above).

The single specimen Syeosea pulchra, Van
Name, 1918 from the Philippines has a thicker
stalk than iy usual for this species, and lacks the
papilla on the abdomen. It may not be correctly
assigned to S. pulehra and probably ts a juvenile
specimen of S, veiziwadui,

Che features Which logether characterise the
present species are its knob-like papilla on the
abdomen, root-like hairs al the base of the stalk,
long, leathery, narrow stalk, small oval to inverted
conical head with the cloacal apertures around
the outer margin of the top of the head, relatively
few male follicles, horizontally oriented abdomen,
ghort-tailed larva, unusual cilis-like extensions
from the ectodermal cells of the stalks of the

MEMOIRS OF THE QUEENSLAND MUSEUM

adhesive organs, and long, conspicuous epicardial
sue in the larval trunk. Herdman (1899) recorded
8 lobes in the testis of the type material of S.
tenuicaulis, No more than 6 and often only 4 male
follicles have been detected in the course of the
present study, Further Herdman reported the
position of the gonads as behind the gut loop.
This is not absolutely accurate — gonads are
always al the side of the gut loop and are posterior
to it only when the abdomen is bent at right angles
to the thorax, placing the gut loop horizontally.

The closest known relative of the present species
is S. brevieauda n. sp. which also has root-like
hairs at the base of a narrow stalk, a conspicuous
epicardial sac in the larva and similar extensions
from the ectodermal cells of the stalks of the
adhesive organs. However in S. brevicauea the
head is flattened and fan-shaped, there are more
numerous mule follicles, no papilla on the
abdomen, the larval trunk ts hall the length of
that of 8. pulched, and its tail is shorter than that
ol the present species.

Sycozoa seiziwadai Tokioka, 1952
(Fig. 57a,b)
Syeozed seiziwadat Tokioka, 1952, p..99. Millar, 1963s,
p. 708; 1975. p. 223,
Sveezoa cerebriformis: Harimeyer. 1919, bo intermedia
p, 12h,
Syeozad pedunculata. Kou, WTA, po 245
7 Sveozoa pulchra; Van Name. 1918, p, 142.
? Syeasaa ? sigilineides: Manniat, 98%, p. (99.

Dr Rr brow

New Reeoros Western Australia (Port Hedland,
WAM 189.87, Dampier Arehipelago, WAM 1050.83;
Cape Preston WAM 802,83), Queensland (Swain Reels,
AM ¥2144), Northern Lerntory (Darwin, QM GH4218,
WAM 108,75).

Previousiy Recororp: Western Australia (Broome,
Holothurian Banks, Bassert Smith Reel — Millar 1963a5
Cape Juobert — Hartmeyer 1919), New South Wales
(Cronulla Kott 1972d). Arafura Sea (Tokiuku 1952),
Philippines (Millar 1975, ? Van Name, 1918).

The record of us occurrenee at Cronulla, NSW, 1s
anomalous for this species in view ol its otherwise
exclusively tropical ragge, (1 ia recorded subtidally to
40m.

Drscriprion

External Arrreananch: Colonies consist ol
thick (up to lem diameter) branching stalks, the
relatively short terminal branches cach expanding
into a short drum- to fan-shaped vooid-hearing
head, circular to oval or elliptical in section, and
absolutely flat on the upper surface. ‘The whole
colony is firm and gelatinous, The upper surface
of the 2ooid-bearing heads is often indeuted where
the cloacal apertures Open around the margin,

THE AUSTRALIAN ASCIDIACEA 2

Adjacent heads sometimes fuse with one another
near the upper surface where they touch,

Zooids are arranged in parallel vertical rows,
one each side of a cloacal canal, with from 10
to 15 functional zooids per row and up to 16 double
rows per head.

The collector has noted that the newly recorded
specimen from Darwin (QM GH4218) was orange
with yellow spots and some black in the colony.
Faint traces of the yellow spots are present in the
surface test of the preserved colony.

INTERNAL STRUCTURE: Zooids are about 3mm
long with the thorax and abdomen of about equal
length. The branchial aperture has a few, minute,
pointed papillae around its border and a thin band
of circular muscles. There are also the usual fine
muscle bands around the atrial aperture. The large
atrial aperture has the usual asymmetry. The
branchial sac has 14 stigmata in the anterior pair
of rows and 12 in the posterior pair. The stomach,
which is slightly smaller than usual in this genus,
is more or less vertical, as is the whole gut loop.
The stomach is wide at its anterior end and tapers
gently toward the pyloric end where it abruptly
narrows. The intestine and rectum together form
a cylindrical tube of even diameter. The gut loop
is relatively long and narrow. A gastric reservoir
was not detected.

Gonads are enclosed in the gut loop toward
its posterior end where they protrude slightly from
the right side. All the mature heads of the available
colonies are male. One from Western Australia
(WAM 1005.83) was collected in October and one
from the Northern Territory (QM GH4218) in
August, The testis consists of 6 long follicles
forming a barrel-shaped clump, with the short vasa
efferentia from each follicle joining the vas
deferens at the distal end. The vas deferens makes
a posterior loop before extending anteriorly along
the rectum to the atrial cavity.

One embryo per brood pouch occurs in
specimens from north-western Australia (Millar
1963a). In these larvae the trunk is relatively short
(0.6mm) and the tail is wound almost completely
around it. Stalks of adhesive organs are wide with
a large cone of adhesive cells, which, in its
epidermal cup, is depressed into the end of the
stalk. Three rudimentary buds are in the larval
test.

Remarks: The colonies of this species have
similar fleshy stalks to those of S. cerebriformis.
However, they are longer than in S. cerebriformis
and are always branched. The zooid bearing part
although often flat is not ribbon-like and pleated
as in S. cerebriformis, although the tendency for
the heads to fuse also occurs in S. cerebriformis

153

(see Herdman 1899). Other differences are
discussed above (see §. cerebriformis). Larvae of
the present species are significantly smaller and
have a longer tail than those of other temperate
or tropical species.

Sycozoa cerebriformis: Hartmeyer, 1919 (f.
intermedia) has the characteristically branched
stalks of the present species, and the same flattened
heads that fuse with one another.

Sycozoa pulchra: Van Name, 1918 from the
Philippines has the same shaped head and fleshy
stalk of the present species and is very likely a
juvenile colony of this species.

Sycozoa? sigillinoides: Monniot 1988 from New
Caledonia is unlikely to be a specimen of the
Antarctic species to which it has been assigned.
Since its larva is the same as S. seiziwadae, it
may be conspecific.

Hartmeyer (1919), Michaelsen (1923) and Millar
(1963a) compared characters of S. cerebriformis
and S. seiziwadai with the South African S.
arborescens Hartmeyer, 1912. The South African
species has a terminal cloacal cavity with a central
aperture, as in S. sigillinoides, thus it must be
distinguished from S. seiziwadai and S. cerebri-
Jormis. The branching stalk, each branch with a
separate head, occurs in both S. arborescens and
in the present species.

The present species has a tropical, western
Pacific range, not apparently extending into
temperate waters — Cronulla, off the New South
Wales coast being the most southerly record to
date.

Sycozoa sigillinoides Lesson, 1830
(Fig. 57c,d. Plate 12e)

Sycozoa sigillinoides Lesson, 1830, p. 436. Hartmeyer,
1911, p. 534. Michaelsen 1924, p. 288. Salfi, 1925a,
p. 2. Van Name, 1945, p. 151. Arnback, 1950, p. 29.
Brewin 1952b, p. 190; 1953, p. 56. Kott, 1954, p, 155;
1957a, p. 99; 1969, p. 26; 1971, p. 18. Millar, 1960,
p. 71; 1982, p. 12. Not Michaelsen, 1930, p. 505 (?
< Sycozoa pulchra, 8. pedunculata).

Colella sigillinoides; Michaelsen, 1907, p. 43.

Syeozoa aff. sigillinoides: Hartmeyer, 1911, p. 489.

Sycozoa (Colella) sigillinoides: Hartmeyer, 1912, p. 313.

Aplidium pedunculatum: Cunningham, 1871, p. 490.

Colella pedunculata: Herdman, 1886, p. 74. Pfeffer,
1889, p. 4(40); 1890, p. 499. Sluiter, 1900, p. 5; 1906,
p. 6. Not Caullery, 1909, pp. 30, 39 (< Syeozoa
pedunculata).

Colella quoyi: Harant and Verniéres, 1938, p. 6.

Sycozoa quoyi: Kott 1954, p. 157; 1957c, p. 1.

Colella ramulosa Herdman, 1886, p. 120. Michaelsen,
1907, p. 53.

Colella umbellata Michaelsen, 1898, p. 371; 1907, p. 54
f. typica, p. 59 f, kophameli. Caullery, 1909, p. 53.

Sveozoa (Colella) umbellata: Sluiter, 1919, p. 12.

154 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 57. Sycozoa seiziwadai (QM GH4218: a, colony; b, male zooid. Svcozea sigillinaides (QM G10148): ¢, zooid;
d, larva. Scales; a, Smm; bye, 0.5mm; d, 0.1mm.

THE AUSTRALIAN ASCIDIACEA 2

Colella perrieri Caullery, 1909, p, 33.
Sycozoa perrieri: Hartmeyer, 1909-11, p. 1439.

DistRIBUTION

New Recorps: South Australia (southern part of
Spencer Gulf, QM GH4171). Tasmania (St. Helens, QM
G10148; Montague L., AM G13077).

PREVIOUSLY RECORDED; Antarctic and Sub-antarctic
(circumpolar, and north to Magellanic area, Falkland
Is. Kerguelen, Heard and Macquarie Is., Chatham I.,
— see Kott 1969). New Zealand (Michaelsen 1924,
Brewin 1952b).

Specimens from Cockburn Sound, Western Australia,
assigned to this species by Michaelsen (1930) are
probably of Sycozoa pulchra as this is the only species
now known to occur there. The records from Albany
and King George Sound (Western Australia) may be
either S. pulchra or S. pedunculata (type locality),

Records of this species from the tropical Atlantic
(Michaelsen 1907) and the tropical Pacific (Michaelsen
1924) Oceans are of isolated heads in the plankton. The
tendency for the heads to separate from the stalks and
float in the plankton may contribute to the wide
geographic range of the species.

The northern limit of the recorded range of this
Antarctic species is off South Australia. However,
records from Australian waters are rare, and so far the
only other Australian localities from which the species
has been taken are off Tasmania.

DESCRIPTION

ExTERNAL APPEARANCE: Colonies consist of
more or less oval heads (up to 2.5cm long and
lcm in diameter) on long, thin and hard stalks.
Stalks taper toward the base where they spread
slightly to form leathery holdfasts. Zooids are in
parallel double-row systems down the side of the
head. The cloacal canals open around the central
test core at the top of the head and the outer
test is sometimes folded in to cover them, often
leaving the central core slightly protruding. In
some colonies (QM GH4171), however, the test
core at the top of the head is disintegrating,
depressed and porous, leaving the zooids
embedded in longitudinal ridges of the outer layer
of test that project into a central cavity to which
the cloacal canals and the atrial apertures of the
zooids are exposed (as in S. cavernosa n. sp.).

Many of the colonies have branching stalks,
with a separate head at the end of each branch.
Millar (1960) believed these multiple colonies to
have developed following regeneration from
persisting stalks.

Living colonies from Tasmania (QM G10148)
were orange. In preservative they are cream and
one specimen (AM G13077) has orange pigment
spots in the surface test.

INTERNAL StRUCTURE: Zooids are relatively
large (4 to 5mm long). The branchial aperture has
3 or 4 frills around its ventral side that may appear

155

to be lobes, but actually result from contraction
of the branchial sphincter muscle. The whole
dorsal border of the aperture is often produced
into a large, delicate lobe, into which the muscles
of the sphincter spread. The atrial muscles extend
out in a similar wide arc in the large, rounded
border of the wide atrial aperture. The atrial
opening is asymmetrical exposing most of the
branchial sac on one side of the body. No muscles
are on the thorax except the fine ones around
the apertures.

There are from 16 to 26 stigmata per row, the
number increasing with the size of the zooids.
Small vegetative zooids at the top of the stalk
have 16 stigmata in the anterior rows. In one of
the newly recorded specimens (QM GI10148),
which has the maximum number of stigmata, and
appears an old colony, the pairing of the rows
of stigmata, even in the small vegetative zooids,
is not as conspicuous as it usually is, the third
and fourth rows being more conspicuously
separated ventrally than the second and third rows.

The gut loop is usually vertical: The large
brownish stomach is about halfway down the
abdomen. It does not reduce in diameter much
toward its pyloric end, but it narrows abruptly
before opening into the intestine. The intestinal
loop is relatively short and the intestine and rectum
form a continuous cylindrical tube. Millar (1960)
observed a mid-intestinal enlargement but this is
not apparent in the present material.

Gonads are at the side of the gut loop, and
when mature project from it. Although they are
in a sac, it does not have a constriction separating
it from the abdomen. Mature gonads are present
in both newly recorded specimen lots, collected
in April (from South Australia) and October (from
Tasmania). Ovaries contain about 10 eggs and 12
to 18 wedge-shaped male-follicles crowd into an
almost spherical clump with the vas deferens
originating at the outer end of the clump and
making the usual posterior loop before extending
anteriorly on the rectum. Colonies are dioecious.
From 6 to 16 embryos and eggs are in a long
brood pouch curved at the end. Embryos are lined
up with their longitudinal axis across the brood
pouch instead of being end to end with their
longitudinal axis parallel to its length.

Larval trunks are from 0.4 to 0.76mm (see Kott
1969) and the tails are wound one and a half times
around the trunk. They have large cones of
adhesive cells rising from the base of the
ectodermal cups in the 3 triradially arranged
adhesive organs. These are depressed into the tip
of the wide stalks (of the adhesive organs) which
form an inflated annular base to each cone of

156

adhesive cells. There is an otolith but no ocellus
in the cerebral vesicle.

Remarks: The characters that separate this
species from all others in the genus are its larger
zooid with more stigmata, larger gonads with more
wedge-shaped male lobes and eggs, and more
embryos in the brood pouch. The cloacal opening,
which comprises a significant distinction from
most other species, is difficult to interpret,
especially when the terminal part of the head is
disintegrating. However, when this happens, the
openings of the cloacal canals appear drawn down
inside the head, and the atrial openings are
exposed to the inner chamber rather than directly
to the exterior as they are in most other species
of the genus, except in S. cavernosa n. sp. In the
latter species the cloacal cavity in the centre of
the head indicates a relationship to S. sigillinoides.

Sycozoa pulchra and S. pedunculata superfi-
cially resemble the present species, but are
distinguished by their separate cloacal apertures
and their short-tailed larvae. The larva of S.
sigillinoides, like that of S. murrayi has relatively
large cones of adhesive cells and a long tail.

Family STOMOZOIDAE new family

The family is erected to accommodate a single
genus Stomozoa Kott, 1957b, formerly regarded
as a member of the Clavelinidae, The genus has
6 fringed lobes around each aperture. Pigment
spots (possibly ocelli) are present at each side of
the base of each of these lobes. A well developed
siphonal velum in each siphon projects outwards
to form a conical structure with a terminal
aperture. There are numerous stigmata and wide
transverse vessels, but no internal longitudinal
vessels. Long vascular stolons, occasionally
branching and terminating blindly in the firm test,
lack both a mesodermal septum and terminal
ampullae. Longitudinal muscles extend from the
apertures and converge into a strong longitudinal
band along each side of the ventral mid-line of
thorax and abdomen. Relatively small gonads are
in the gut loop, the testis with pear- to club-shaped
follicles, and the ovary containing only one or
at most 2 eggs.

The gonads of this genus often are difficult to
see. Those of the 2 new Australian species and
the 2 previously described are similar (Millar 1955,
Kott 1957b). Millar (1977) reports ‘spent gonads’
in the Brazilian material of S. roseola. However,
his figure suggests the small group of male follicles
reported may be part of the mass of tangled tubules
of the pyloric gland present in the same position
in the newly recorded Australian material. The

MEMOIRS OF THE QUEENSLAND MUSEUM

ovary of S. murrayi: Monniot, 1988 has more eggs
than the one or 2 usually found. Only a single
large embryo has ever been found in the atrial
cavity of a Stomozoa sp. Larvae of Stomozoidae
have triradially arranged adhesive organs, 2 dorsal
and one ventral, each with a wide and shallow
axial cone in an epidermal cup. The test is firm
and gelatinous throughout.

Kott (1957b) assigned the genus Stomozoa to
Clavelinidae, believing the smooth border of the
muscular velum homologous with the smooth-
rimmed apertures of that family. However, the
pigment spots at the base of the lobes around the
outside of the apertures suggests these fringed
lobes are more likely homologues of the lobed
apertures of Diazonidae. Clavelinidae are further
distinguished by their soft and flaccid thoracic test,
larger ovaries, more numerous embryos incubat-
ing in the atrial cavity, and longitudinal thoracic
muscles that extend postero-dorsally (rather than
postero-ventrally as they do in the present family).
Although they lack the clavelinid frontal plate the
larvae are generally more like Clavelina larvae
than those of Distaplia (see also Millar 1977).

The present family does not appear closely
related to the Holozoidae. The vascular stolon
lacks an epicardial septum and any sign of
vegetative zooids developing from the narrow
vascular stolon as in Holozoidae. Thus it is
possible replication could be by transverse division
of the zooids as in Diazonidae and Polycitoridae.

Stomozoidae are separated from Diazonidae by
the absence of internal longitudinal branchial
vessels, large viviparous larvae, and firm test over
the upper thoracic part of the colony.

Their closest relatives may be Polycitoridae, as
zooids of both have broad ventral muscle bands
in the abdomen and a long oesophagus. Stomo-
zoidae are separated from the latter family by the
long vascular stolon and larvae with triradially
arranged adhesive organs.

Kott (1981) in discussing the relations of
Euherdmania digitata, and E. dentatosisphonis,
the latter species with fringed lobes around the
apertures similar to those of the present family,
thought both may be synonymous with Stomozoa
roseola (Millar, 1955), However, Millar (1977) had
already considered these relationships, and
concluded that the presence of gonads in a
posterior abdomen and incubating embryos in the
abdomen characteristed Euherdmania as distinct
from Stomozoa. Other features distinguish these
two genera. In particular, Euherdmania has
tubular larval adhesive organs, a folded stomach,
separate zooids and lacks a vascular stolon.
Further, although ocelli are in the centre of the

THE AUSTRALIAN ASCIDIACEA 2 157

lobes around the apertures of Exherdmania they
are not at each side as they are in Stamezca, Thus,
it appears Auherdmania and Stomozod are not
closely related and the fringed lobes around the
apertures of some Eukerdmania species may not
be homologous with the similar ones in Slomozua.

The small ovary and few large embryos
produced in the known species of the present
family suggests it has a long evolutionary history
as a colonial organism, Available evidence offers
no alternative to the hypothesis of early isolation
from a diazonid ancestor, possibly in common
with Polycitoridae, the latter lamily diverging
from Stomozoidae with loss of the ocelli around
the wpertures, reduction in size of zooids and
larvae, and acquisition of median (rather than
triradial) arrangement of larval adhesive organs,

Genus Stomozoa Kott, 1957

lype species: AYumozea murray’ Kotl, 1957b (<
Clavelina roseola Millar, 1955).

Since Stomozoidae is monotypic. the generic
characters are also those of the family.

‘There are 3 species. The type species is known
from a remarkably wide, albeit tropical, geogra-
phic range, viz. the Brazilian and Guyana Shelves
(= Diazena gigantea; Monniot, C., 1970; S.
mturravi: Millar 1977, 1978), South Africa
(Clayvelina roseola Millar, 1955; 8. murray: Millar
1962), New Caledonia (8, miurrayvi; Monmiot, 1988)
and the Red Sea (8. murrayi Kott, 1957b). No
uppurent morphological diflerences in specimens
from these locations exist to indicate speciation
in either adult colonies or zooids, Larvae are
known only trom Brazilian populations. Only a
single larva is produced at a time by each zooid.
Accordingly, the strategies for gene flow are: not
apparent. Both Australian species described below
appear indigenous, one a temperate species
recorded on a number of occasions from the Great
Australian Bight, the other (from the tropics)
recorded once from Heron |, and 4 times from
the north-western coast. Both species haye fewer
gligmata in the adult zooid than S. roseele, but
otherwise are similar lo jt. Laryae, Known from
both, are only half the size of the larvae of S.
raxenla.

Stomozoa australiensis n.sp,
(Fig, 58, Plate |2f)
DistRipe tion
Tort Locariry South Australia (Topgallant f. Great
Australian Bight. 5m, coll, S‘Shepherd 29,3,82, holotype
OM GH974; Ward [,, Great Australian Bight, clitfs and

caves, Om, coll, S.Shepherd, 124.83, paratypes, OM
G11946 GH2392).

Fortune Reeorts, South Australia (Great Austral-
ian Bight, OM GH1300),

DescRiprion

Exteenat Aveeargance: Colonies are up to
3cm high, and consist of numerous translucent,
almost spherical heads up to 1.5em in diameter,
with slightly narrower. opaque sialks joined to
one another basally. The internal test is firm and
translucent throughout. Some patches of orange
pigment cells are around the zooids, and minute
(0.02mm) morula bodies are evenly scattered
through the test wbout 0.05mm apart, These are
not calcareous. In expanded colonies the large.
fringed Jobes around the apertures of the zouids
protrude {rom the upper surface, and sometimes
the whole anterior partion of each zooid projects.
When zooids ace withdrawn the upper surface of
the colomies ts fat, Living colonies are deserihed
as bright pink, although photographs do not
confirm that description, some variation is likely,
Colonies are white in preservative. Epibionts grow
amongst the stalks — in one colony a botrylli¢d
adheres closely to the test of the stalk,

INTERNAL STRUCTURE, Zooids, tightly enclosed
in the firm test, are difficult to remove. When
contracted they are about lem long. The 6
characteristic lobes around each aperture are sub-
divided into 5 or 6, each subdivision with a
terminal narrow point, Orange ocelli are at each
side of the base of each of the lobes, ‘The fringed
lobes Mit inte corresponding lobes of the test, The
median dorsal lobe of the branchial aperture and
the ventral lobe of the atrial aperture are larger
than the others. On the thorax about 4 longitudinal
muscle bands from the branchial aperture and
about 8 altogether from the intersiphonal space
and atrial wperture extend toward the ventral
border of the zooid where they join into the 2
characteristic wide ventral hands extending the full
length of the zooids — one on cach side of the
ventral midline, The ventral bands extend almost
to the posterior end of the abdomen where they
terminate abruptly around the posterior vascular
stolon where it emerges from the ventral side of
the abdomen. In most specimens the strong
contraction of the ventral muscle bands has drawn
the proximal end of the vascular stolon away trom
the Up ol the abdomen to just opposite the
stomach, Anteriorly, the muscles extend into the
muscular Velum around each aperture. The fringed
lobes themselves do not contain conspicuuus
muscles. About 40 fine branchial tentacles are
behind the base of the branchial vellum, Vhuraces
of these specimens are so contracted that it was

158 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic, 58, Stomozoa australiensis n,sp.: a, general shape of colony (paratype QM GH946); b, single lobe of a
colony with zooid openings distended (holotype QM GH974); ¢, branchial lobes surrounding muscular aperture
through which the tentacles are protruding (holotype QM GH974); d. zooid from dorsal surface (paratype
QM GH2392); e, abdomen showing branches of pyloric gland, ovary surrounded by minute male follicles,
and the heart (paratype QM GH946); f, larva (paratype QM GH946), Scales: a,b, 2mm; ¢,f, 0.2mm; de, 0.5mm.

THE AUSTRALIAN ASCIDIACEA 2

not possible to determine whether the tentacles
were in one or more than one circle. The opening
of the neural gland is circular.

Twelve to 14 rows of long, narrow stigmata,
with about 30 per row, are separated from one
another by wide transverse membranes. Dorsal
languets are wide and dorso-ventrally flattened
where the transverse vessels cross the dorsal sinus.

The oesophagus is long, but often is wrinkled
owing to contraction of the body muscles. The
stomach, in the posterior end of the abdomen,
has 6 fine ridges interrupting the glandular lining.
An oval posterior stomach is in the descending
limb of the gut loop, separated from the stomach
by a narrow mid-intestine, usually also obscured
by contraction, The anus opens at the base of
the atrial cavity. The pyloric gland from the distal
end of the stomach divides into numerous
branched tubules that encircle the ascending limb
of the gut from opposite the stomach to about
halfway up the abdomen. A one-egg ovary with
apparently a large polar body is on the right side
of the gut loop. The testis, beneath the ovary,
consists of pear- to club-shaped follicles. Fine-
branching vasa efferentia converge to the base of
the vas deferens. There is often a mass of minute
cells and granular material (that may be associated
with the vegetative process) in the loop of the gut
and around the outside of the posterior end of
the intestine. This material obscures the gonads
and the pyloric gland.

In one specimen lot (QM GH946) a single large
embryo is in the atrial cavity. The larval trunk
is almost spherical, Imm in diameter. Three
rounded ampullae project between the triradially
arranged adhesive organs. Each adhesive organ
has a wide axial protrusion in an epidermal cup.
The tail is wound slightly more than halfway
around the trunk. The larval test like that of the
adult colony is tough, white and almost opaque.

Remarks: The species is distinguished from
Stomozoa roseola (Millar, 1955) by its small
number of rows of stigmata, S. roseola from the
Brazilian Shelf having 26 to 32 rows with up to
60 in a row (Kott 1957b, Millar 1977), and
specimens from the Guyana Shelf having 19 or
20 rows (Millar 1978); and by the size of the larvae,
that of S. roseola (2mm trunk diameter) being
about twice the size of the present species. The
adhesive organs of the present species are the same
as those of S. roseola. The rounded swelling Millar
(1977) observed on the top of the central knob
of cells in the adhesive organs may be a hyaline
cap as in Distaplia larvae (see Cloney 1977), It
is not present in the larvae of S. australiensis from
South Australia. Otherwise the species are

159

remarkably similar — the colonies, muscle bands,
gut and lobes of the apertures all being identical.
Spicules in both Red Sea and Brazilian specimens
of S. roseola are not present in S. australiensis.
Differences between the 2 Australian species are
discussed below.

Stomozoa bellissima n.sp.
(Fig. 59. Plate 12g)
? Polycitor aurantiacus: Hartmeyer 1919, p. 108.
Not Atopogaster aurantiaca Herdman, 1886.

DistRIBUTION

Typr Locatity: Western Australia (Bundegi Reef,
Exmouth, coll. N. Coleman 14.8.72, AMPI 74, holotype
QM G9267), Queensland (Heron I., NE Point 3m, coll.
D. Parry 1.11.85, paratype QM GH4918).

FurtHer Recorps: ? Western Australia (Cape
Jaubert — Hartmeyer 1919).

DESCRIPTION

Externat. ApPEARANCE: The holotype has a
dome shaped head of about 3cm diameter set on
a thick stalk of only slightly less diameter. The
stalk separates into 4 branches, 2 of which fuse
with one another basally to form a thick loop.
The head and stalk each occupy about half of
the total height (4cm) of the colony. The test is
firm but gelatinous throughout, that on the head
being translucent, while the outer surface of the
stalk is opaque and brownish. The paratype colony
is smaller (containing only 8 zooids) with test
projecting from the upper surface over the anterior
ends of the zooids. As in the holotype, the test
becomes firmer toward the base where the
diameter of the colony is reduced to form a
relatively narrow stalk. Zooids are rather sparsely
distributed. They open all around the head and
converge in toward the centre and base of the
colony. In both specimens they are contracted and
withdrawn from the surface, The internal test is
firm and contains the long vascular appendages
of the zooids irregularly criss-crossing one
another.

The test around the apertures is produced into
hollow, fringed lobes, which accommodate the
lobes of the body wall around the apertures of
the zooids. The living specimens have a clear test
with poppy red zooids (QM GH4918) or the colony
is a pink colour throughout (QM G9267).

INTERNAL STRUCTURE: The contracted zooids
are robust and about Icm long, although in their
extended condition they may be up to twice this.
The body wall is muscular and siphons and
thoraces are contracted in both newly recorded
specimens. The branchial aperture is terminal, and
the atrial aperture is up to two-thirds of the body
length distant from it. The branchial apertures

160 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 59, Stomozoa bellissima n.sp.: a, z001d (holotype QM G9267); b, colony (holotype QM G9267); e,d, lobes
of branchial aperture (holotype QM G9267); e, colony (paratype QM GH4918); f, zooid (paratype QM GH4918):
g, larva (paratype QM GH4918). Scales: a,f, 1mm; b,e, 5mm; ¢,d, 0.2mm; g, 0.5mm.

THE AUSTRALIAN ASCIDIACEA 2

open below the atrial apertures on the surface of
the colony, and the dorsal surface of each zo0id
iy Just beneath the surtace test.

The border of each aperture is deeply divided
into 4 flaps or lobes, each subdivided along its
straight or rounded outer edge into a fringe of
a variable number of rounded or pointed
projections — about 4 on the atrial lobes and up
to 8 on the branchial lobes.

Both apertures of the zooids in the holotype
colony are transverse. The branchial opening has
its 3 largest lobes on the dorsal rim, and in living
ypecimens these probably direct the opening
downwards toward the substrate. Four larger
lobes are on the posterior rim of the atrial siphon
which in some of these contracted zovids folds
up anteriorly against the zooid. covering the 2
lobes an tbe anterior rim, Each of the projections
on the outer fringe of each lobe has a small orange
Pigment spot in the centre. Also a conspicious
spherical pateh of pigment (possibly an ocellus),
yellow in preserved specimens, is on each side ol
the base of the pnmary lobes, The latter pigment
spots oceur in pairs, cach located close to its
partner on the adjacent lobe. ‘Those on the 3 large
dorsal lobes of the branchial aperture and 4
posterior lobes of the atrial aperture are larger
than the others, The muscular velum characteristic
ol this genus is inside cach aperture.

A. strong band of circular muscles surrounds
each aperture, Longitudinal muscle bands radiate
from each siphon, but the most numerous muscle
hands (at least 15) are those that extend ueross
the dorsal surface between siphons. All longitud~
inal muscles converge toward the ventral surface
to form 2 wide bands extending tle whole length
of the body, one on each side of the mid-yentral
line. Some intersiphonal muscles extend across the
dorsal surface just hehind the branchial siphon
and in front of the atrial siphon. On the ventral
side of the branchial siphon, longitudinal bands
van be seen radiating away from its base

About 40 crowded branchial tentacles are of
various sizes, but all relatively long and slender,
The (rangulur dorsal languets on the dorsal sinus
have long points, The thoras is wide, with 14 or
1S rows of about 40 stigmata and wide transverse
vessels between the rows.

The oesophagus is long, opening into the rather
narrow stomach ahout two thirds of the distance
down the abdomen. The stomach has a suture-
line, but although ut may be collapsed and appear
folded there are no structural grooves or folds
imits wall. A wide duodenal area, a narrow, curved
mid-intestine and a Jongish oval posterior stomach

tol

are also in the descending limb of the gut loop.
and the rectum occupies the whole of the ascending
limb. A circular mass of long, almost club-shaped
male follicles converge into the centre to join the
vas deferens on the right side of the gut loop.
A small sac-like ovary with one or2 ova is oulside
the male follicles.

A long, line, vascular appendage, with a few
muscle fibres extending along it. prajects fram the
left side of the pole of the gut loop. These vessels
have 2 channels, but no mesodermal septum. They
resemble the Lest vessels of Phiebobranchia. They
do not ruu parallel to one another. but criss-cross
in the internal test of the colony.

The specimen from Heron L. collected in
November has a single larva in the atrial cavity,
Its trunk is oval, Imm long, and the tail is wound
about halfway around the trunk. The triradially
arranged adhesive organs ure the usual sessile
shallow depressions with an axial cone. Short
ectodermal ampullae alternate with the adhesive
organs.

Remagxs: The species differs from the other
Australian species of this genus (S. australionyix
Tsp.) in its posteriorly positioned atrial aperture.
the more numerous muscles between the siphons,
the smooth rather than ridged internal lining of
the stomach und oval rather than spherical larval
Irunk,

The colony of the present species is not broken
Up inky separate lobes as that of S. a@usiraliensiy,
although this could be a variable character, The
species do have about the same number ol Jong,
fine branchjal tentacles and rows of stigmata and
both have long testis follicles, the same arrange-
ment of their muscles, and dhe sume small, sac-
like evary.

Hartmeyer’s specimens from north-western
Australia are wrongly assigned to Polveftor

aurantiacus (Herdman, 1882) from Bass Strait

‘The Basy Strait species has a short oesophagus
and a posterior abdomen, and belongs to
Polyelinidae. Hartmeyer’s specimens had numer-
ous Jong. fine branchial tentacles, Jong zomids of
about |.4em, 15 rows of sti@mata and reddish-
violet coloured cushion to stalked colony, about
Sem in maximum dimension with the stalk divided
basally as in the present colony, Although
Hartmieyer records the siphonal lobes deeply
separated from one another, he does not deseribe
gither a fringe on their ouliter border, or ocelli at
their base, Nevertheless, his specimens were
contracted, the apertures probably were obscured
and if is not impossible that the specimens are
of the present species,

162

Family POLYCITORIDAE Michaelsen, 1904

Colonial, with zooids usually entirely embedded
in common test. Zooids are divided into thorax
and a long abdomen (containing gut and gonads),
and reach almost to the base of the colony. Usually
only a short, often branched, vascular appendage
is at the posterior end of the abdomen. Both
branchial and atrial apertures are 6-lobed, on
conspicuous siphons and open separately to the
exterior.

Thoracic musculature usually consists of strong
external longitudinal bands and an inner layer of
transverse muscles. The former continue in two
strong bands along the abdomen, one each side
of the ventral mid-line. These do not extend on
to the posterior abdominal vascular appendix. The
usual circular muscles surround each siphon and
sometimes (in Eudistoma) these form strong
conspicuous sphincters. Zooids are particularly
contractile. They are often (but not always)
arranged in circular systems with the atrial
openings in a tight group in the centre of the circle,
sometimes in a depression homologous with a
rudimentary cloacal cavity. When contracted,
zooids appear to detach from the surface test and
are withdrawn toward the base of the colony.

Replication is by horizontal strobilation of the
abdomen, as in the Diazonidae. Fertilisation
apparently is usually in the atrial cavity, and eggs
and embryos at different stages of development
can be found there. However, in Cystodytes and
Polycitorella and occasionally in Polvcitor and
Eudistoma (Polycitor circes, P. annulus n.sp.,
Eudistoma incubitum n.sp.) fertilisation is at the
base of the oviduct, development proceeds as
embryos move up the oviduct, and is completed
in the atrial cavity or, in some cases, in a brood
pouch at the top of the oesophageal neck (see
also the Arctic Polycitor vitreus: Berrill, 1948a,
Eudistoma clarum: Van Name, 1945 and E&.
olivaceum: Berrill, 1947b), The 3 larval adhesive
organs are in a median vertical line at the anterior
end of the larval trunk, except in Polycitor circes
and P. annulus n.sp, (which have them triradially
arranged). The adhesive organs are stalked, with
a flat-topped cylindrical protrusion of columnar
cells in the centre of a cup of specialised epidermal
cells, except in Cystodytes (in which the protrusion
is conical) and in Brevicollus n.gen, (which has
no axial protrusion). The larval ectoderm is also
produced into undivided or bilobed, conical,
flattened or cylindrical ampullae in the mid-line
(alternating with the adhesive organs), and/or in
one to 3 lateral rows along each side of the adhesive
organs. Fine extensions from ectodermal cells

MEMOIRS OF THE QUEENSLAND MUSEUM

expand into terminal vesicles in the larval test in
some species (see Annotated Glossary: larvae). In
larvae of this family there are usually 2 rows of
stigmata but occasionally 3 (see E. maculosum
n.sp., £. muscosum n.sp., E. purpureum n.sp.).
The larval tail is especially wide and flat, the trunk
contains a large yolk mass, and the larvae give
the appearance of being long-lived and strongly
swimming.

Polycitorid and holozoid genera were formerly
included with clavelinid genera in the Distomidae
Giard, 1872 which became a junior synonym of
the Polycitoridae Michaelsen, 1904 (after the type
genus — Polycitor Renier, 1804). Subsequently
polycitorid and holozoinid genera were contained
in the Polycitorinae of the Clavelinidae
(Michaelsen 1930, Huus 1937) until Berrill (1950)
separated the holozoids as Holozoinae, In addition
to Distaplia and Sycozoa, Michaelsen (1930)
believed the Polycitorinae included Sigillina (with
subgenera Archidistoma Garstang, 1891; Eudis-
toma Caullery, 1909; Paessleria Michaelsen, 1907;
Hyperiodistoma Michaelsen, 1930; Sigillina,
Savigny, 1816), Pol/ycitor Renier, 1804, Cystodytes
Drasche, 1883 and Tetrazona Michaelsen, 1930.
Of the subgenera of Sigillina (which Michaelsen
characterised by the presence of 3 rows of stigmata,
and the absence of cloacal systems), Hyperiodis-
toma and Sigillina, both with a posterior
abdominal vascular appendage containing an
extension of the epicardium and with the
longitudinal body muscles extending along it, are
here considered members of the Holozoidae (see
above).

Polycitoridae as defined here contains six genera
— Archidistoma, Eudistoma (including Paessle-
ria), Polycitor (including Tetrazona), Polycito-
rella, Cystodytes and 2 new monotypic genera
Brevicollus n.gen. and Exostoma n.gen. Based
primarily on replication, phylogenetic affinities of
Polycitoridae appear with the Diazonidae, from
which it is separated by its smaller embedded
zooids without internal longitudinal branchial
vessels, smaller gonads, viviparous larvae, and
more prolific replication, It also appears related
to the Stomozoidae having similar longitudinal
muscles forming a pair of ventral bands on the
abdomen, and a long oesophagus.

The zooids of Sigillina, especially those species
lacking muscles on the posterior abdominal
vascular appendage (S. fantasiana, S. nigra),
resemble those of Eudistoma and Polycitor in
several ways, This resemblance is enhanced where
polycitorid species have a larger than usual
vascular stolon (Eudistoma glaucum, EF. superla-
tum n.sp.). However, the relationships of Sigi/lina

THE AUSTRALIAN ASCIDIACEA 2

spp. to the Polycitoridae do not appear to be close.
Polycitoridac are distinguished not only by their
method of replication but also by their much
smaller sooids, & continuous coat of transverse
thoracic museles, absence of an extensive nrea of
unperforated pharyngeal wall anterior and
posterior W the stigmata, and (in all except
Brevicollus negen., Crstedvies and Polyertorella)
a long oesophagus with the stomach at the
posterior end of a long abdomen, absence of a
stalked brood pouch, and relatively small larvae
with small adhesive organs with small circular
uxial cones rather than the long ridges and
platlorms found in Sigi/line,

The two largest genera (Eueistomia and Polj'e-
itor) of the Polycitoridve are similar. Awelistoma
is distinguished from Polveitor by its smaller
vooids with short thorax, only 3 rows of stigmata,
smaller gonads, and smaller larvae. Rueistomea has
a characteristic long duodenal region, and small,
almost spherical, and always smooth stomach,
while Polvetror has a short duodenum, and a large
and sometimes folded stomach. In Aveistame the
anterior row of stigmata is deflected dorsally along
each side of the mid-dorsal line — a phenomenon
possibly associated with size reduction Known in
Pyenaclavellaand Cysicdyies butnotin Palveilor.
Further, the test of Polveirar usually is transparent
or translucent while in Ewelstame it often is
opaque, and with few exceptions, is more brightly
coloured than the test of most Polveiter spp.
Eveisroma larval adhesive organs have a thicker
axial protrusion than those of Polveifor, and more
ectodersnal ampullae, Zooids are arranged in
rudimentary circular systems in kudisfoma,
Polyeltrorella and Cystodyres but only rarely in
Palyeitar. Palycitorella and Cystodvies also have
zooids that resemble one another in having
particularly strong muscles. They are distinguished
primarily by the form and distribution of
calcareous spicules in the test. Eyesroma negen,
is unusual in the development of a cloacal system
and its zovids are adapted to accommodate that
habit. Brevicolluy n.gen. tas many characters that
indicate a divergence from the Polycitoridae. and
therefore its phylogeny is problematical, and its
inclusion in this family is proVisional.

Archidistoma is known principally from its type
Species A. aggregatum Garstang. [891 trom the
English Channel. Both its zooids and larvae closely
resemble those of Eudistonra, and Uartmeyer
(1924), Van Name (1945) and Berrill (1950)
Suggested that separate generic status lor Ayedlis-
tome and Archidistoma may be unjustified since
the only difference hetween them is the form af
the colony — the former species has embedded

163

zoids While those of Are/ticistoma fram the type
location have zooids almost entirely separate, the
basal part of the zooid only being embedded in
common basal test. Ewelixtome cdiscederadium Kou.
1981 from Fiji with vooids separate for at least
half of their length resembles colonies assigned
lo Archidixioma avgregatuin trom the Atlantic
coast ot North America (Van Name 1945, fide
Berrill 1950), and Madagascar (Vasseur 1969). In
view Ol the wide geogruphie range represented by
these records. it seems probable similarities in
these small colonies are due lo convergence, and
separate species may be involved, However. at this
stage there is no clarification of their generic slalus.
Species such as £ /avsanj, E bulhatunm nsp., and
£. murrayi Kott, 1957a with the anterior ends of
the zooids protruding from the colony represent
an intermediate condition which tends to support
the view that Lhe genera are synonymous.
Arehidixsroma has priority over Eudixtoniu, in the
event that they are synonyms,

The family affinities of Japanese colonies
(Archidistoma ageregatune, Nakauchi, (960, 1966)
with vooids almost entirely embedded, and
prominent posterior abdominal vascular stolons
are uncertain. Specimens from New Caledonia
assigned to the genus Archicistera by F. Monniot
(1988) are species of Pyeneclavella (see aboye).

Eudistoma and Polveijor are well represented
in Australia with both indigenous and Indo-West
Pacific represemiatives. The cosmopolitan Cysro-
dytes dellavhiajei also occurs around the Ausiral-
ian continent, and there are 2 indigenous species
of Polyeitorefla, Vhe lamily is aot well represented
in Antaretic waters, and despite the relatively high
numbers of Australian indigenous species is
temperate waters if is probable that its Origin is
in the tropies, Where it abounds.

Kry to THe GENERA oF PoryeiraRipar
(* not recorded from Australia)

1. Cloacal systems extensive... Evestanma ngen,

Cloacal systems rudimentary or absent... ...2
2. Stigmata in 3 rows 2.02.02... ee eee eee eed 5
Stigmata in = 3 rOWSs ©) 6) ep ee ee ee yee

3, Zovids separate ....... 60.6." Arehidisienra
Zooids embedded .,.-,......-05- Budisiomea

4. Calearcous spicules present in the test... ...5
Calcureous spicules not present im the test. 6

5. Stigmata in 4 rows.,..,-.,..,--, Cystodptes
Stigmata in > 4 rows .......0.. Podpeitoreia

6. Parustigmatic vessels Presents ss ceeece ere eee
Oe cick erest Bre | Brevicollus ngen.
Purastigmatic vessels oot present... Palvedtor

MEMOIRS OF THE QUEENSLAND MUSEUM

164

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THE AUSTRALIAN ASCIDIACEA 2

Genus Polycitor Renier, 1804

Type species: Polycitor crystallinus Renier, 1804

Species of this genus have relatively large zooids
with a long oesophageal neck more than twice
the length of the thorax. The rounded stomach
is in the descending limb of the gut at the posterior
end of the abdomen. There are from 4 to 20 or
more rows of stigmata. Parastigmatic vessels are
not present. Zooids are completely embedded in
firm test. Colonies are stalked or sessile and
cushion-shaped, upright or spherical. They range
in size from only | or 2cm in diameter to about
15cm. Zooids are invariably relatively long, with
a long oesophageal neck. They stretch from the
surface of the colony to the base. In sessile,
rounded colonies zooids converge to the centre
of the base where the colony is fixed to the
substrate. In preservative zooids are invariably
found contracted and drawn away from the
surface. Body musculature consists of longitudinal
bands extending from each of the siphons, along
the thorax and onto the abdomen forming 2 wide
ventral bands. Circular sphincters surround each
siphon. An internal layer of circular muscles on
the thorax sometimes is inconspicuous. Six to 12
branchial tentacles alternate with a variable
number of smaller ones in a circle slightly anterior
to the larger ones.

Larvae usually have a trunk of about Imm,
although sometimes (P. circes, P. giganteus) it is
longer. Ectodermal ampullae are. median, some-
times bilobed and alternate with adhesive organs.
The central protrusion of the adhesive organs is
narrow and cylindrical. Adhesive organs some-
times are arranged triradially (P. annulus n.sp.,
P. circes).

The genus Distomus Savigny, 1816 is a junior
synonym of Polycitor Renier, 1804. Savigny’s
name is also preoccupied by Distomus Gaertner,
1774, a synonym of Amphicarpa (Styelinae) (see
Michaelsen 1904).

Polycitor is relatively diverse in temperate
Australian waters being represented by 6 indigen-
ous species. Only 3 species, viz. P. circes, P.
annulus n.sp. and P. translucidus are known from
tropical waters. Only the latter has been recorded
from elsewhere in the Pacific. Po/ycitor circes and
P. annulus are among the few tropical indigenous
species known in any family of the Ascidiacea.
Nine of the 10 species known from Australia are
indigenous.

Key TO THE SPECIES OF POLYCITOR
RECORDED FROM AUSTRALIA
1. Stomach with > 4 parallel structural folds ..2
Stomach with 4 or no structural folds ..... 6

165

2. Colony with long cylindrical stalk ..........
tes in ee ee P. calamus n.sp.
Colony without long cylindrical stalk ......3

3. Stomach with 20 or more stomach folds and

more than 15 longitudinal thoracic muscles

beage 0 ips olete 3 beF 0 oct 3h 4 Prete ny sys Oe P. circes

Stomach with less than 20 stomach folds and
less than 15 longitudinal thoracic muscles

PERG S cae wet aed acces radbahh abd ies 4

4. Transverse thoracic muscles conspicuous ....
cd's sips hp oes Soy aek oe bees P. cerasus n.sp.
Transverse thoracic muscles not
GONSPICWOUG o 4s aes ck ad ase bie nub co serps eae ge

5. Colony transparent with black zooids.......
seagate Slee glare he elle ates P. annulus n.sp.
Colony opaque with whitish zooids.........
RSS stele dle dg Vag ha rage dts P. nubilus n.sp.

6. Stigmata in 10 or more rows; 4 stomach

ColdS.. 20 caPPaicatepteades4 P. giganteus
Stigmata in < 10 rows; stomach without
TORAS ae spl Eat oles nee nec cle pin cee ine io 7

7. Base of colony entire .......... 2... eee ee 8
Base of colony divided. ...........0..0005 9

8. Stigmata in 6 rows...........-- P. obeliscus
Stigmata in > 6 rows ........ P. translucidus

9. Base of colony divided into regular branches,
each branch containing a single zooid.....

pees ¢ eee eet alee 2 SD E323? P. subarborensis

Base of colony divided into irregular branches,
each branch containing up to 3 zooids....

be oates Reh cp yageeeges P. emergens n.sp.

The species collected by the Siboga Expedition
that Sluiter (1909) described as Polycitor have only
3 rows of stigmata. Most are Eudistoma spp., and
these and others are referred to in the discussion
of that genus (see below).

Polycitor annulus n.sp.
(Fig. 60)
? Polycitor circes; Millar, 1975, p. 205 (part, specimen
from the Philippines ZMC 20.11.41).

Dist RIBUTION

Typr Locariy; Queensland (Capricorn Group,
Heron I., under rubble near reef edge, low tide, coll.
P. Kott May 1987, holotype QM GH4350; Wistari Reef,
September 1984, paratypes QM GH4348; Wistari Reef,
November 1986, paratypes QM GH4351; Heron I., May
1987, paratypes QM GH4356).

FurrHer Rreorps: Queensland (Heron LL, QM
GH4346-7 GH4349 GH4352 GH4354-5 GH4433
GH4472 GH4582; Wistari Reef, QM GH4353 GH4434;
Swain Reefs, QM GH4346).

DESCRIPTION

ExTeRNAI, APPEARANCE: Colonies are small,
wedge-shaped lobes up to Icm high. In life the
upper surface is convex with zooids projecting

166

MEMOIRS OF THE QUEENSLAND MUSEUM

Fic 60, Polvettor annulus n.sp_: a, colony (paratype QM GH434x); b-d, zooids showing incubating embryos
(holotype OM GH4350); e, zooid showing gut loop and gonads (paratype QM GH4348): f, larva (QM GH4472).
Seales; a, Smm: b-e, mm; £ 0.1mm.

slightly from the surface, their openings showing
as black circles in clear, transparent, glassy test.
Zooids themselyes are black. becoming blackish
green in preservative and retaining thal colour over
a long period in alcohol. The test is soft and may
become slightly cloudy in preservative.

INreRNAL SrrvUc TURE: Small zooids, even when
narcotised, contract away from the surface of the
colony. Zooids contain dark pigment, concen-
trated in patches behind the neural complex,
around the base ol the branchial siphon, over the
anterior end of the endostyle, and in longitudinal
bands down the length of the thorax. Each
aperture has 6 rounded lobes. The thorax is
muscular with about 18 parallel longitudinal bands
extending onto the abdomen as. 2 wide ventral

bands. There are 8 to 10 rows of rectangular
stigmata with about 20 per row — although, owing
to the contraction, these are difficult to count.

The oesophagus ts long, but found wrinkled and
contracted in all zauids examined: and. also as
a result of contraction, the rectum is pleated and
folded along its length. The stomach, in the
posterior end of the abdomen, is usually obscured
by the rectum and by large embryos that start
their development at the base of the oviduct. The
stomach is short and broad with 12 to 15 shallow,
parallel, internal longitudinal ridges, Gonads are
present in the gut loop. They consist of a fairly
large cluster of relatively large male follicles and
a 4- or 5-egg ovary. Although up to 3 embryos
can be found moving up the abdomen, only one

THE AUSTRALIAN ASCIDIACEA 2

appears mature at a time and is found just behind
the postero-dorsal corner of the thorax, projecting
from the top of the oesophageal neck. Neither
embryos nor larvae have been found in the thorax.
Apparently fertilisation occurs at the base of the
oviduct.

In the Capricorn Group mature gonads were
observed only in specimens collected in September
(QM GH4348). However, developing embryos are
present in May (QM GH4350) and March (QM
GH4347). Thus, although neither mature gonads
nor embryos were seen in specimens collected in
October or November, breeding apparently occurs
intermittently through the year. Larvae are large
in relation to the size of zooids, the trunk being
about 0.8mm long. The tail is wound about three-
quarters of the way around the trunk. There is
an ocellus and otolith. The 3 anterior adhesive
organs have relatively short, thick stalks, and a
short, relatively thick, flat-topped axial protrusion
set in the usual epidermal cup. The adhesive organs
are triradially arranged rather than being in the
median line. The larval epidermis at the base of
their stalks is expanded into rounded swellings.

Remarks: Superficially this species resembles
Sigillina signifera in the distribution of pigment
in its dark zooids, and transparent test. However,
colonies and zooids are both smaller, and zooids
lack a posterior abdominal stolon.

This species is characteristically polycitorid in
all its characters except for the retention of the
large larvae in the abdomen and the triradial
arrangement of the adhesive organs — as in P.
circes (see below). The former possibly is due to
the size reduction of zooids without an associated
reduction in the size of the larvae. The triradial
arrangement of adhesive organs may be a primitive
character retained in these species but lost in most
species of the Polycitoridae.

Polycitor circes resembles the present species
also in the large number of longitudinal thoracic
muscles, although it has more stomach folds and
about twice the number of rows of stigmata.

One of the specimens from the Philippines
(ZMC 20.iii.41) assigned to P. circes by Millar
(1975) has similar zooids and colony to those of
the present species. However, although it broods
larvae in the abdomen, and has triradial adhesive
organs as in P. annulus, the larval trunk is much
larger (2.5mm) and despite the small colonies,
specimens probably are correctly assigned.

Polycitor calamus n.sp.
(Fig. 61. Plate 13a,b)
DistRIBUTION
Type Locatiry: South Australia (Archipelago Cove
40m, coll. W. Zeidler 28.1.82, holotype SAM E2058,

167

paratypes SAM E2051; Great Australian Bight, Flinders
1, in Posidonia 8m, coll. N. Holmes 1 1.4.83, photo index
PE0054-R998, paratype SAM E2057; Great Australian
Bight, Avoid Bay 15-20m, coll. N. Holmes and S.
Shepherd 9.4.87, paratypes QM GH4187-8 GH4308).

FurrHer Recorps: South Australia (Spencer Gulf,
SAM E2052-6). New South Wales (Kurnell Peninsula,
AM Y2197),

The species is common in Posidonia beds.

DESCRIPTION

EXTERNAL APPEARANCE: Colonies are robust,
firm, cylindrical stalks up to 10cm long and 1.5cm
diameter with a short spherical to conical head
of slightly greater diameter than the stalk. The
test of the stalk is transversely wrinkled, almost
completely opaque. It narrows slightly toward the
base, where its outer surface often becomes quite

Fic. 61, Polycitor calamus n.sp. (paratype QM GH4308):
a, colony; b, zooid, part of oesophageal neck excised.
Scales: a, 5mm; b, 2mm.

168

leathery. Basally the test spreads out into flat hold-
fasts over the hard substrates, such as scallop
shells, to which the colonies are attached. One
or more stalks can arise from the basal test, and
occasionally a stalk divides into two branches at
about one third of its length from the base. The
test of the head is gelatinous and translucent in
preservative, and in life a bright vermilion. Patches
of pigment remain on the surface of preserved
specimens. Zooids, only up to 20 per colony, open
around the head.

INTERNAL STRUCTURE: Zooids are long, extend-
ing from the surface of the head to the base of
the stalk. In all preserved colonies the thorax of
the contracted zooids is withdrawn from the head
down into the stalk. Apertures are close together.
Both have 6 well-defined lobes, those on the dorsal
rim of the branchial aperture being larger than
the ventral ones, suggesting the aperture is directed
away from the atrial aperture in life. The body
musculature is oblique to longitudinal, resembling
clavelinids, with a formula 8E,5B,2A. The muscles
run obliquely toward the postero-dorsal corner
of the thorax where they extend in two strong
bands along each side of the long narrow
oesophageal neck that occupies most of the length
of the zooid.

In the preserved zooids, 6 large coiled branchial
tentacles are behind about 12 shorter, rather
stumpy ones. The neural ganglion and gland are
both large and oval. The neural duct is short and
wide, opening in a simple, circular, anteriorly
directed aperture in the prebranchial area. There
are 9 to 13 rows of long rectangular stigmata with
about 35 in each row. Transverse sinuses between
the rows of stigmata extend out into long pointed
dorsal languets over the large and conspicuous
dorsal sinus that interrupts the rows of stigmata
in the mid-dorsal line along the length of the
pharynx. Dorsal languets are not flattened, and
parastigmatic vessels are absent. A short unper-
forated area of pharyngeal wall lies anterior to
the stigmata.

The relatively small stomach is in the posterior
end of the abdomen. It has 12 distinct rounded
folds along its length. No subdivisions of the long
post-pyloric part of the gut were detected in these
specimens, nor were gonads, although vegetative
cells were in the abdominal wall suggesting a
vegetative phase. Only one colony (SAM E2052)
had abdominal strobilae.

A juvenile colony with 4 zooids was taken in
January from South Australia. Most other
specimens were collected in January, one lot in
April (SAM E2057) and the specimen from New
South Wales in May. Data suggest a restricted

MEMOIRS OF THE QUEENSLAND MUSEUM

autumn breeding season, and replication from
January until the winter months.

Remarks: The species is distinctive and readily
identified by its small, vermilion head, long stalk
and particularly long oesophageal neck. All of
these characters, together with the absence of
circular muscles, readily distinguish it from
Polycitor cerasus n.sp., which is cherry red in life,
and sessile. It differs from most Po/ycitor in having
oblique muscles.

Polycitor cerasus n.sp.
(Fig. 62a. Plate 13c)

DistTRIBUTION

Type Locacity: South Australia (Nuyts Archipelago,
Franklin I., loc, c Breaking Reef, 15m amongst algae,
coll. N. Holmes 22.2.83, photo index PE044 R8II
holotype SAM E2080, paratype QM GH4365),

FurtHer Recorps; None.

DESCRIPTION

EXTERNAL APPEARANCE: Only the type material
is available. Colonies are sessile and dome-shaped,
about 3cm high and 2.5cm diameter. All the test,
except the outer 0.5cm thick layer over the upper
surface, is crowded with sand particles, making
it hard. A little sand is also present in the outer
layer of test between the zooids. Zooids converge
towards the centre of the colony, from the outer
surface, Living colonies are cherry red, although
this is lost in preservative.

The lower part of the colony probably is buried
in sand, and irregular, sandy extensions from
around the periphery of the basal surface probably
help to anchor it.

INTERNAL StRuCTURE: Zooids are robust, and,
in this type material, about lcm long contracted.
Apertures are both anterior, and open separately
to the outer surface of the colony. The rim of
each aperture is deeply divided into 6 distinct
lobes. The body wall is muscular with an almost
continuous but thin outer layer of longitudinal
bands, and a conspicuous inner layer of circular
fibres. Longitudinal muscles form the usual wide
ventral bands of muscle along the abdomen.
Triangular dorsal languets are relatively narrow
and have a long tapering point, There are 10 rows
of about 25 stigmata. The stomach, just over
halfway down the abdomen in these contracted
specimens, has 8 rather irregular folds in the right
(parietal) side. A post-pyloric duodenal area exists,
and a short oval posterior stomach is constricted
off before the rectum bends around in the pole
of the gut loop.

Gonads consist of an extensive, rather diffuse
mass of pyriform follicles and a few large eggs
on the right side of the gut loop. Male follicles

THE AUSTRALIAN ASCIDIACEA 2

BN
TS
li

Fic. 62, Polpecitor cerasus n.sp. (paratype QM GH4365):
a. zooid. Polycitoer circes: b, zaoid (QM GH4367):;
c. larva (AM Y1303). Scales: a, mm; b, 2mm, e¢,

0.3mm,

169

spread through the loop onto the lett side. Two
short, branching blood vessels project from the
posterior end of the zooid.

Remarks: The species is unusual in having a
mass of sand embedded in the test, making the
colony hard to sce and obscuring its colour.
Similar relatively large zooids converging toward
the base of the colony occur in many other species
of this genus (e.g. P. nubilus nsp., P. cirees and
P, annulus n.sp.). The present species lacks the
dark pigment found in the preserved specimens
of P. cirees and P. annulus. Colonies resemble
those of P. obeliscus in their general form, sessile
habit, and the distribution of sand within the
colony. Zooids of the present species with their
folded stomach distinguish it from P. obeliseus,

Polycitor circes Michaelsen, 1930
(Fig. 62b,c)

Polveuar circes Michaclsen, 1930, p. 495. Rott 19574,
p. 84; 7 1966, p. 281. Millar 1963a, p. 710: 1975, p,
205 (? part, specimen from Marongas 20,3.1914),
Monniot 1Y8X, p. 207.

Polyettor gelatinosa Kott, 1957a, p. 83 (part, not
specimens from South Australia).

? Polveiter renziwadai Tokioka, 1952, p.96.

Dist RI BU TION

New Recorns Western Australia (Passage L. WAM
1039.83; Broome. AM Y2192 Y2199; Dampier Archipe-
lago. WAM 1035.83 1042.83; Cervantes Reef. WAM
(78.87 180.87, Houtmans Abrolhos, WAM 367.80 QZ
GH2110, WAM 199.88, AM Y2191 ¥2195; Cockburn
Sound WAM 1036.83). Queensland (Martha Ridgeway
Reel, QM GH4367).

Previousty Reeoroen: Western Australia (Cape
Boileau, Broome — Millar 1963a: Cape Inscription
AM Y1292 Kott 1957a; Shark Bay — Michaelsen 1930;
Cockburn Sound ~- Michaelsen 1930; AM Y1302 Y1306
V1309- 10 P. geletinosa Kott, 19574). New Caledonia
(Monniat 198%). Philippines (Millar 1975).

Although there is a preponderance of records from
north-western Australia, the newly recorded specimen
from Queensland suggests the species will be recorded
from other tropical locations in the western Pace. [1
is large, conspicuous, and not likely to be overlooked,

Description

ExTernat Appearance: Colonies are large up
to Yem high and 7em in diameter, sometimes
almost flat-topped but at other times mushroom
Lo club-shaped, narrowing toward the base where
there usually is a short, thick stalk, devoid of zooid
openings. Otherwise zooids open on the upper
surface and sometimes on the sides of the colony
and converge toward the top of the stalk. One
colony (QM GH4367) is spherical, fixed by a small
part of the base, but with zooid openings only
on the upper half of the surface. The test is firm,

170

gelatinous and translucent. In preservative zooids
are dark blue.

INTERNAL StTRuctTurReE: Zooids are robust,
measuring about 2cm in length even in a
contracted state. In preservative zooids have dark
pigment, especially in the thoracic body wall and
transverse branchial vessels, and forming a
conspicuous patch at the anterior end of the
endostyle. Branchial and atrial lobes, 6 of each,
are rounded. The body musculature is strong,
consisting of about 20 longitudinal bands that
extend along the abdomen as two wide ventral
bands. The usual circular muscles are around each
of the siphons, however the inner layer of
transverse muscles is inconspicuous. Six large but
stumpy branchial tentacles alternate with 3 smaller
ones. The neural ganglion is large and spherical,
The duct of the neural gland is short and the
opening is circular and directed anteriorly. The
dorsal languets are long and tapering. In the
pharyngeal wall a wide, unperforated area exists
anterior to the 18 to 23 rows of stigmata. Up to
50 stigmata in the anterior rows are reduced to
about half that number posteriorly.

The oesophagus is long, and invariably is
wrinkled in these contracted zooids. It opens into
the small, rounded stomach in the posterior end
of the abdomen. The stomach wall has 20 to 30
narrow, parallel longitudinal folds. A constriction
between an inconspicuous posterior stomach and
the rectum is in the pole of the gut loop. The
anal border is divided into two large smooth lips.
Gonads, a mass of pyriform male follicles with
a 3 or 4 egg ovary, are in the gut loop posterior
to the stomach.

Ova are fertilised at the base of the oviduct and
develop as they move up the abdomen. Their
incubation is completed in the top of the abdomen
just posterior to the atrial cavity rather than in
the atrial cavity as in most other species of the
genus. Larvae are present in April in colonies from
the Abrolhos (WAM 367.80) and from Rottnest
I. (> P. gelatinosa Kott, 1957a). The larval trunk
is about 2mm long, with a large part of that length
(about two-thirds) anterior to the oozooid taken
up by a yolk mass. The short thick stalks of the
3 (triradially arranged) adhesive organs are not
expanded into ectodermal ampullae. The central
protrusion of each adhesive organ is rather narrow
and cylindrical,

Remarks: The relatively numerous rows of
stigmata, longitudinal muscles on the thorax, and
longitudinal stomach folds, as well as the larvae
and the pigmentation of the zooids distinguish this
species from Polycitor giganteus which has a
similar bulky, and firm gelatinous colony and a

MEMOIRS OF THE QUEENSLAND MUSEUM

similar long branchial sac that narrows towards
its posterior end. The long yolk-filled anterior part
of the larval trunk is unique. The abdominal
brooding of the larvae and triradial arrangement
of adhesive organs was also observed by Millar
(1963a and 1975), and occurs also in P. annulus
n.sp. from Heron I. (see above).

In preservative the colonies sometimes resemble
those of Sigillina grandissima, especially since the
zooids are the same dark colour. The latter species
is distinguished by its long vascular stolon,
relatively short oesophagus, smooth stomach and
more conspicuous transverse muscles. Eudistoma
superlatum n.sp. also forms massive but lobed
colonies, and has a long vascular stolon (unlike
the present species).

Millar (1975) assigned 3 colonies — 2 from the
Philippines and one from the Kei Is — to this
species. They are all small finger- or club-shaped
lobes, joined basally, and are not the large
gelatinous cushions of the present material.
Therefore only the Marongas specimen 20,3.1914
(which has the characteristic larva) can be
positively assigned to this species. The specimen
from the Kei Is resembles Clavelina arafurensis
in the proportion of oblique to longitudinal
muscles, although the orange vesicles in the test
reported by Millar have not been recorded for
C. arafurensis. One colony from the Philippines
(ZMC 20,111.14) may be a colony of Polycitor
translucidus, with characteristically long zooids
and parallel longitudinal thoracic muscles.

Specimens from New Caledonia (Monniot 1988)
have a smaller than usual larval trunk (1.6mm
long).

Polycitor emergens n.sp.
(Fig. 63)
Dist RIBUTION
Tyre Locauiry: New South Wales (off Cronulla, 60m,
coll. J. McIntyre 17.6.65, holotype AM Y1124, paratypes
AM Y837).
Furruer Recorps: None.

DESCRIPTION:

EXTERNAL APPEARANCE: Colonies consist of
upright cylindrical finger-like lobes arising from
a common basal mass of test concealed by an
almost spherical mass of sand. The sand can be
removed to show the basal mass of test subdivided
into irregular branches covered with fine,
branched and rather ragged, flat, narrow, tag-like
projections of the test to which the sand adheres.
These act as roots holding the colony firmly in
the sandy substrate. The upright, free lobes of the
colony are up to 2cm long, and the basal sandy
part is about 1.5cm in diameter. The test is

THE AUSTRALIAN ASCIDIACEA 2

Fic, 63, Polycitor emergens n.sp. (paratypes AM Y837):
a, colony; b, colony with sand removed from basal
half showing zooids extending out into basal root-
like branches; c, thorax. Scales: a,b, 2mm; c, 0.5mm.

translucent and relatively soft on the upper free
ends of the cylindrical lobes, but becomes tougher
toward the base, where the surface layer is
transversely wrinkled and opaque. The basal sand-
covered part of the test is tough.

Zooids are parallel to one another and open
to the surface on the top of each upright lobe
where the test is particularly delicate. They are
long, and the posterior ends of from one to 3
or more extend out into each branch of the basal
part of the colony.

INTERNAL STRUCTURE: Zooids are contracted
in both the holotype and two paratype colonies.
Both apertures are anterior, each with 6 well-
defined lobes. Nine or 10 strong parallel longi-
tudinal muscles have the formula 6B,2D,2A. They
extend in 2 broad bands along the ventral part
of the abdomen. The internal layer of circular
muscles is inconspicuous, dorsal languets are
triangular with a long point, and there are 8 rows
of stigmata with about 20 per row.

The usual long oesophagus opens into the
smooth stomach in the posterior third of the

171

abdomen. The anal opening is bilabiate. Gonads,
present in the gut loop, have relatively small
pyriform male follicles.

Remarks: The tendency for the basal part of
the colony to break up into branches into which
the posterior ends of the zooids project has been
recorded only in this genus — in the present species
and in Polycitor subarborensis (see below). The
present species can be distinguished by its small,
upright, cylindrical colony lobes, and its irregular
basal branches, each containing the posterior part
of several zooids. Only the tips of the sandy basal
branches of P. subarborensis are produced into
the fine and sometimes relatively long branching
root-like tags produced from the test. In the
present species these occur all over the basal test
and hold the thick coat of sand around the base
of the colony. Zooids of P. subarborensis also
have more numerous muscles than the present
species.

Basal stolons of certain clavelinid and pycnoc-
lavellid colonies which support separate zooids are
not homologous or even analogous with the basal
branches of these Polycitor colonies in which the
upper parts of the zooids are entirely embedded.
Basal branches of both the present species and
P. subarborensis appear, at least functionally,
analagous to the basal root-like processes of
stolidobranch ascidians, by which they are
attached to or are rooted in the substrate.
However, they are not homologous. The present
colonies are unusual in that the projections by
which they are anchored contain the posterior ends
of the zooids and are not merely solid outgrowths
of the test. Zooids of P. subarborensis and the
present species project to the end of the basal
branches of the colony. Thus these basal branches
seem homologous with basal parts of colonies of
other species in the genus, and probably are the
result of subdivision separating the posterior ends
of the zooids from one another, rather than simple
outgrowths of the test.

It is the form of the colony and its tough test
that distinguishes the species from Polycitor
translucidus which has similar long, but narrow,
zooids with only about 8 rows of stigmata and
a smooth stomach.

Polycitor giganteus (Herdman, 1899)
(Fig. 64. Plate 13d-h)
Polyclinum giganteum Herdman, 1899, p. 79.
Polycitor giganteus: Kott, 1957a, p. 83; 1972a, p. 9;
1972b, p. 171; 1972d, p. 244; 1975, p. 2: 1976, p.
57. Millar, 1963a, p. 709. Not Sluiter, 1919, p. 10.
Polyclinum globosum Herdman, 1899, p. 80.
Poycitor gelatinosa Kott, 1957a, p. 83 (part, specimens
from South Australia).

172 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic, 64, Polyeitor giganteus: a,b, zooids (SAM E2065, AM E1841): ¢, thorax (SAM E2076); d, gonads and
proximal part of rectum (SAM E2076); e-g, successive stages in development of larvae (AM Y8&05), Scales:
a-d, |mm; e-g, 0.2mm.

THE AUSTRALIAN ASCIDIACEA 2

DASTRIAN TION

New Recowos. Western Australia (Port Hedland,
WAM [038 83, Shark Bay, WAM 821.83 OAF GH2/4/).
South Australia (Great Austrahan Bight, SAM E2067,
QM GHY25 GH9431 GH1291 GH2518 GH2386 GH 2388;
Spencer Gull, SAM £20602 E2068. OM GH4853,
Nuyts Archipelago, SAM E2063-4, OM GH2300: Yorke
Peninsula, SAM £2066, QM GH2373; St Vincent Gulf,
SAM E2065. QM G9314: Kangurou 1. SAM E2069,
OM GI1990)), Tasmania (Flinders L QM GITI291;
Oyster Bay, AM W358), Victoria (Ninety Mile Beach
QM G1 1862; Bass Strait, MV: Gabo 1...QM G9478).
New South Wales (Bermagui, AM Y2194; Jervis Bay.
QM G10021-4; Port Stephens, AM Y2000: Botany Bay,
OM Gl0l64; Clarence River mouth, AM E141:
Arrawarra, GH4357; Solitary 1. QM G9635; Lord Howe
1, QM GH4376). Queensland (Mooloolabah, QM
()H4324).

Previousiy Reeorormee South Australia (Great
Australian Bight — SAM 62072 F2075-6 Kote (972b
1976: St. Vincent Gulf AM Y1304 P. velatinuse: Kou.
19578, SAM 19239 £2071 £2074 Katt 197 2a: Investigator
Strutt Kott }972b, West | Kott 19720 1975)
Vietoria (Lakes Entrance AM Y1I1I30 YISI2 Kou
19574: Port Phillip Bay — AM ¥1295 Kort 1957u 1976,
Millar (963a; Western Port AM ¥1283 Kott 1976,
Mallacoota talet — Kott 1976). New South Wales Jervis
Bay. Port Jackson — AM Y3930 03934 Herdman 1KYY,
AM Y¥1294 YIS05 YISOR Kott 19574. Millar 1963a;
Botany Bay AM YSO09 YROS YRIO YS31 Kote 1972d).

The species is common in shallower waters (subtidal
to 24m) from southern Australiato Port Jackson (NSW).
but hay also been taken down to 40Um off the NSW
goast off Bermagut (AM Y2194). It appears an
Australian indigenous species recorded most eommanty
around the south-eastern half of the continent.

DeseriPrian

Exiersar Amer arance: Colonies are massive,
up to l2em in diameter, They are spherical to
lop-shaped, fixed by a part of the undersurface
which usually forms a short, thick stump that just
vlevates the colony above the substrate. The test
is always firm and gelatinous, and completely
transpurent and glassy to cloudy and translucent.
Zooids usually open around the sides and upper
surtace of the colony, although occasionally in
relatively small colomes, zoom openings are
confined to the upper surlace, Zooids converge
from the surface in toward the centre of the base
of the colony, In preserved colonies they are
invariably found contracted and withdrawn trom
the surface, The zooid openings are arranged
evenly on the surface of the colony but their
posterior ends cross ane another when they are
withdrawn from the surface. Zoaids are not in
systems. In living colonies the test is usually glassy
and transparent. and vovids are either bright
orange or white and can he seen 4s white or yellow
streaks padinting oul from the centre of the

173

transparent colonics. In preservative zooids are
either white or pinkish, however, there is no
correlation between living and preserved colours
— colonies reported by the collectors to have had
bright orange zooids are either pinkish or while
in preservative, as are zooids reported to be white
when fiving.

Internal StaucTURE: Zooids are robust and
long. even in a contracted state they can meusure
to Jem, and in life are much longer. They have
6 well defined lobes around each aperture, The
body musculature is strong, consisting of 12
longitudinal thoracic bands on each side which
continue along the length of the abdomen as two
wide ventral bands of muscle. Thoracic bands
extend trom the branchial siption, from the apace
between the siphons. and from the other siphon
according vo the formula 6B,3D,3A. None of the
longitudinal musele bands cross the endostyle. The
transverse or cirevlar museulature is usually
inconspicuous, except for the sphincter muscles
around cach siphon. The transverse wrinkles of
the ectodermal layer of the body wall resulting
from contraction of the thoracic muscles can be
mistaken for transverse muscles on superficial
examination of the zooids. The neural complex
is large and the opening of the neural gland is
asimple circular opening directed forwards, Six
large but rather stumpy branchial tentacles
alternate with shorter ones. Dorsal languets on
the dorsal sinus are long and pointed. There are
12 to 16 rows of long rectangular stigmata,
invariably found contracted. In a large specimen
from Bass Strait there are 16 rows on the right
and an additional half-row that does not reach
the dorsal line on the left. Although often difficult
to count, there appear to be between 30 and 40
stigmata in all rows except the pasterior ones. bn
one relaxed specimen (SAM E2076) there are 40
in the anterior and 20 in the posterior rows.
Parastigmutic vessels are absent.

The oesophagus is long, opening into the
elongate stomach near the posterior end of the
abdomen, The stomach wall has 4 grooves. and
when collapsed it forms 4 pronounced olds. The
posterior stomach. about the same length as the
stomach, and separated from it by @ short
duodenal area, opens into the rectum in the pole
of the gut loop. The anal border ts bilabiate,
Gonads, consisting of numerous male follicles and
a small ovary, are contained in the posterior end
of the gut loop behind the stomach at the posterior
end of the abdomen. There are 2 or 3 short vaseular
appendages,

Embryos. occur in specimens taken from South
Australian waters in September (QM GH4853)

174 MEMOIRS OF THE QUEENSLAND MUSEUM

and October (SAM E2075) but not in February
or May. In November they are in specimens from
Port Phillip, Bass Strait (MV) and Botany Bay
(AM Y816). However, they are present also in
June in Botany Bay (AM Y805), October at Lord
Howe I. (QM GH4376), and January at Lakes
Entrance and Rottnest I. (AM Y1310). Thus
records suggest sexual reproduction may occur
throughout the year. Ova probably are fertilised
in the atrial cavity, where up to 12 eggs and
embryos at various stages of development occur.
The larval trunk is 1.4mm long, and the tail is
wound half to three quarters of the way around
it.

Single median ampullae are in the anterior mid-
line dorsal and ventral to and alternating with
the stalked adhesive organs. Ampullae subse-
quently become bilobed. In mature larvae they
often appear as paired lobes. An otolith and
ocellus are in the cerebral vesicle, and a large mass
of yolk in the centre of the larval trunk. The
protruding part of each adhesive organ is rather
narrow and cylindrical.

Remarks: Preserved colonies of this species are
readily confused with Polycitor circes which also
has large gelatinous colonies, and zooids with a
long thorax decreasing in width posteriorly.
However, the zooids of P. circes have more
numerous longitudinal muscle bands, rows of
stigmata and stomach folds.

Kott’s (1976) suggestion that the orange in
certain colonies occurs when the zooids are not
withdrawn from the surface was not confirmed
in the present study although eggs and larvae of
both white and orange zooids contain the same
orange pigment in the yolk. Orange zooids also
have pigment in the body wall, and it is absent
from the white zooids. Apparently there are two
colour phases of this species. The great range in
numbers of rows of stigmata referred to by Kott
(1957a et seq.) probably results from difficulties
in counting these in contracted zooids.

Polycitor nubilus n.sp.
(Fig. 65a,b. Plate 131)
DistTRIBUTION
Type Locatity: South Australia (Investigator Group,
Flinders I., Lighthouse Point in caves and overhangs
8m, coll. N. Holmes, photo index PE0071/R969,
holotype SAM E2079).
FurTHER Recorps: None.

DESCRIPTION

EXTERNAL APPEARANCE: The holotype colony
is the only specimen available. It has an almost
spherical head about 4cm in diameter and a short
thick stalk about half the diameter of the head.

Fic. 65, Polycitor nubilus n.sp. (holotype SAM 2079):
a, zooid; b, colony outline. Polycitor obeliscus
(holotype MV H167): ¢, zooid; d, colony outline.
Scales: a, 0.5mm; b,d, lcm; c, [mm.

THE AUSTRALIAN ASCIDIACEA 2

Zooids are relatively crowded, opening all around
the head. In life the colony is a cloudy, cream
colour, with translucent circular areas over each
4ooid, separated from one another by narrow
bands of opaque test. In preservative the test of
the head is gelatinous, translucent and a slightly
rosy colour.

INTERNAL STRUCTURE: Zooids are dark in
preservative, with pigment particles scattered in
the body wall, especially around the anterior end.
Zvoids are muscular, and contracted. Each of the
apertures is deeply divided into 6 pointed or
rounded lobes. Longitudinal thoracic muscles
from the siphons and the intersiphonal interval
have the formula 6B,3D.3A. They continue along
the abdomen as two wide yentral bands and
terminate at the posterior end of the zovid.
‘lransverse muscles are inconspicuous, Twelve
fairly long tentacles in a posterior circle alternate
with 12 shorter ones in a second circle. Small.
irregularly spaced tentacles are in an anterior
circle. The simple opening of the neural gland is
directed anteriorly. There are 11 rows of aboui
20 rectangular stigmata.

The long, oesophagus opens imto the stomach
in the posterior quarter of the abdomen. The
stomach wall has 15 parallel. longitudinal folds.
An oval posterior stomach is constricted off from
the rectum in the pole of the gut loop. Gonads
ure present in the gut loop. There is a short,
branched vascular extension [rom the posterior
end of the body.

Remarks: Although photographs of the living
specimen do not show the zooids pigmented, the
dark pigmentation of the preserved specimens ts
conspicuous and distinctive, Unlike Polycitur
annulus n.sp.. Which has darkly pigmented living
zooids as well as preserved ones, the pigment
particles are not in longitudinal lines down the
thorax in the present species but are scattered
rather evenly in the body wall. becoming more
crowded anteriorly. Branchial sacs are similar in
the two species, In addition to the arrangement
of the pigment particles in preseryed specimens,
P. annulus usp. differs from the present species
in having a clear transparent test and more
numerous (18) longitudinal muscle bands. Of the
other Polyciter spp. with a folded stomach, P.
calamus n.sp, is distinguished by its colour and
long cylindrical stalk, P. circes has more numerous
longitudinal thoracic muscles and rows of
sugmata, und P. cerasus o.sp, has conspicuous
circular thoracic muscles as well as the longitudinal
ones. The larva of the present new species is not
known.

Polycitor abeliseus Rott, 1972
(Fig. 65d)
Polvenor abeltseum Kott, 72h, p. U7.

Dis rhiau rion

Nrw Rereornps None.

Previovsiy Ricowpep: South Australia (Investiga-
tor Strait = holotype MV H167).

DescRIPTion

Exrreenar Appraraner: The holotype is the
only colony available. The colony is an upright
cone 5cem high and about 2.S5cm in diameter
around the base. It is firm. with sand throughout
the internal test. Sand is also in the surlace test
around the base of the colony, but absent from
ihe surface test of the upper part. Zooids open
all over the upper surtace of the colony. and they
converge inwards at an angle to the surface.
Between sand grains the test is firm and
translucent.

INieRNAL SiRuctuRE: Zooids are about Ymini
long bul are contracted. The thorax has an almosi
continuous coat of outer longitudinal muscle
bands overlying the layer of circular ones. The
longitudinal muscles continue along the length of
the abdomen in 2 wide bands.

There are 6 rows of about 12 stigmata. However.
stigmata ure hard ta count owing to the
contraction of the thorax — and it is possible
there are more. The oesophageal necks of the
zoids are particularly long. An almost spherical,
relatively short and smooth-walled stomach, an
expanded duodenal area and a short rounded
posterior stomach are in the descending limb of
the cut loop al the posterior end of the abdomen.
Mature gonads. are not present in these zooids
(collected in January). The larvae are not known.

Remarks: The species is unusual in Palpeitor
in having embedded sand, and relatively few rows
of stigmata. The zooid, muscular, and thus
resembling P. eircey, is readily distinguished from
it by the smooth stomach and embedded sand.

Polycitor subarborensis Kott, 1957
(Fig. 66a-c)
Polveitor subarborensis Rott. L9S7a. p. 81,

Distrinu dios

New Rrearus: None,

Perviousty Recornren: New South Wales ( Ulladulia,
AM Y1298 hototype).

Description

Exrernat Arprarance: The colony is a small,
more or less dome-shaped. glassy. transparent,
sessile cushion about lem in diameter but only
about 0.5em high, with 9 or 10 cylindrical, sand-
covered root-like structures about lem long

176 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 66, Polycitor subarborensis (holotype AM Y1298): a, colony; b, zooid, ¢, larva. Polycitor translucidus: d,
colony (QM G4332); e, zooid with embryos (QM GH4345); f, much contracted zooid with embryos (QM
GH4343); g, larva (QM GH4325). Scales: a, 2mm; b,e,f, 1mm; c,g, 0.2mm; d, 5mm.

THE AUSTRALIAN ASCIDIACEA 2

projecting down and out from the under surface
of the glassy dome. Occasionally they branch once
along their length. The sand is embedded in their
surface test. Zooids open on the upper glassy
surface of the colony and project down into the
sandy root-like branches, each terminal branch
containing the posterior end of one zooid, The
terminal ends of these branches also have some
rather short irregular test processes to which
additional sand adheres. An irregular knob of
zooid-free test growing from the upper surface may
be an abnormality.

INTERNAL StRucTURE: Zooids are withdrawn
from the upper surface in this contracted colony.
Both apertures are anterior, with a sphincter
around the base of each short, 6-lobed siphon.
Longitudinal muscles are numerous, arranged on
the thorax according to the formula 12B,2D,2A.
The 6 most ventral muscles lie fairly close to one
another, crowded together along each side of the
endostyle. Transverse muscles are inconspicuous.

On the abdomen, the muscles form 2 or 3
exceptionally wide bands leave only the dorsal
border muscle-free. There are 8 rows of about 20
stigmata. The oesophagus is, as usual, long,
opening into the smooth-walled stomach in the
posterior end of the abdomen. Gonads are large,
with short, lobed, pyriform male follicles and
about 12 eggs in the ovary.

The holotype colony, which was collected in
January, has single embryos near the surface of
the head, although none in the zooids themselves.
These embryos may have been ejected by the zooid
as it contracted and withdrew from the surface
while being collected. The larval trunk is
moderately large (Imm long), with a thick, tough
test. The tail reaches the anterior end of the trunk.
Three median adhesive organs alternate with
ampullae. These ampullae are single and median
in the immature larvae, but they subsequently
subdivide into paired lobes, as in the larvae of
Polycitor giganteus. The central protrusion of the
adhesive organs is narrow and cylindrical.

Remarks: Both larvae and zooids (with 8 rows
of stigmata and the smooth-walled stomach that
may collapse into 4 folds) are similar to those
of P. translucidus. However, the present species
has more longitudinal thoracic muscles, and the
division of the basal half of the colony into sandy
root-like process is an almost unique feature,
shared only with P. emergens n.sp. (see above).

Polycitor translucidus Kott, 1957
(Fig. 66d-g)
Polycitor translucida Kott, 1957a, p. 81. Monniot and
Monniot 1987, p. 70; Monniot, 1988, p. 209.

177

Polycitor circes: Millar 1975, p. 205 (part, specimen from

the Philippines ZMC 19. iii.41).

? P. erystallinus: Monniot, 1988, p. 209.
DistTRIBUTION

New Recorns: Western Australia (Shark Bay, WAM
82.83 1041.83; Cockburn Sound, WAM_ 1034.83).
Victoria (Wilson's Promontory, MV F54184). Queens-
land (Maroochydore, QM GH4329 GH4358; Wistari
Reef, QM GH4333 GH4339 GH4436; Heron I., QM
G10010 GH4325-32 GH4334-8 GH4340-5 GH4368
GH4370 GH4583).

Previous_y REcorpeEp: Western Australia (Rottnest
I. — Kott 1957a), French Polynesia (Monniot and
Monniot 1987). Philippines (Millar 1975). New
Caledonia (Monniot 1988).

The few records of this species, other than from Heron
I. where collecting effort has been greater than elsewhere,
may be because of its cryptic habit and its completely
transparent glassy test. Its recorded range suggests a
West Pacific species probably with the usual wide
geographic range of that fauna (see Kott 1985).
DESCRIPTION

EXTERNAL APPEARANCE: This beautiful species
has a wedge-, mushroom-, top-shaped to upright
almost cylindrical colony tucked into small
crevices from which its upper surface protrudes.
The narrow upright colonies, in which the head
is not expanded and the number of zooids are
fewer are apparently younger than the others.
Colonies are up to 2cm in diameter on their upper
surface — which may be flattened or rounded,
and about |.5cm high. They are fixed by a short
stalk often separated from the expanded head by
a slight constriction. Zooids extend down into the
base of the stalk. The test of the head is absolutely
clear and glassy and the zooid openings show on
the surface as fine white rings that disappear as
the zooids withdraw from the surface when they
are disturbed.

In life the thoraces of the zooids are ‘buff yellow’,
‘salmon buff’, ‘maize yellow’, to ‘deep chrome’
(Ridgeway 1886). The stomach is usually ‘cad-
mium orange’ and developing embryos are also
orange. In preservative they are cream to pink,

INTERNAL StRucTuRE: Zooids, when partially
relaxed, are about 7mm long. They have 6 rounded
lobes around each aperture, and a shallow band
of circular muscle fibres around the base of each
short siphon. Nine to 12 well separated, longi-

tudinal muscle bands on the thorax have the
formula 6-8B,1D,2-4A. These continue along the

abdomen in the usual 2 wide ventral bands. Twelve
rather long tentacles alternate with small almost
rudimentary ones. Dorsal languets are long and
pointed. There are 8 to 10 rows of about 20 to
30 stigmata. The larger colonies (MV F54184,
WAM 1041.83) have the maximum numbers of
longitudinal muscle bands and stigmata.

178

The oesophagus is long but usually wrinkled,
while the rectum is bent, undulating and folded
in the fixed specimens — which, even though
narcotised, and with the thorax relaxed, always
have a contracted abdomen. The stomach, in the
posterior end of the abdomen has a suture line,
but apparently no folds. There is an oval posterior
stomach and a constriction in the pole of the gut
loop separates it from the rectum, The anal border
at the posterior end of the atrial cavity is bilabiate.

Gonads with small pyriform sometimes bilobed
male follicles are in the gut loop, posterior to the
stomach. Larvae probably are fertilised and
complete their development in the posterior part
of the atrial cavity, where up to 6 embryos are
crowded. Larvae are in colonies collected in May,
July, August and November, but not in colonies
collected between January and March — the
hottest time of the year at Heron I. where diurnal
temperature variations in the intertidal area are
high.

Larvae are small, with a trunk 0.6 to 0.8mm
long. The tail is wound half to three-quarters of
the distance around the trunk, The 3 adhesive
organs, on narrow stalks, alternate with conical
ectodermal ampullae in the median line. The
central protrusion of the adhesive organs is narrow
and cylindrical.

Remarks: One of the principal characteristics
of this species is the small size and simplicity of
its zooids (which probably is a result of its small
size), viz. relatively few rows of stigmata and
muscle bands, a smooth stomach (rather than one
with folds), and small larvae. The colour of the
living specimens resembles the range found in
Polycitor giganieus, although the test is clearer
and more glassy in the present species.

Specimens from New Caledonia assigned to the
Mediterranean P. crystallinus by Monniot (1988)
may be synonyms of the present species although
their colonies are larger than usual. Both zooids
and larvae are similar, and it is possible the
colonies increase in size with age, and in sublittoral
habitats.

Genus Cystodytes Drasche, 1884

Type species: Distoma dellachiajei Della Valle,
1877.

The genus is characterised by the presence of
a capsule formed of layers of overlapping saucer-
shaped calcareous spicules that encases the
abdomen of each zooid, and into which the whole
zooid sometimes withdraws when it contracts. The
cavity in the firm, gelatinous and translucent test
in which the zooids are contained is hourglass-

MEMOIRS OF THE QUEENSLAND MUSEUM

shaped — the thoracic and abdominal compart-
ments being partially separated by a constriction
of the test with a circular constrictor muscle
embedded in it. This circular muscle is connected
to the zooid around the top of the oesophageal
neck. The strong musculature consists of a thoracic
meshwork of longitudinal and transverse bands,
with the longitudinal muscles continuing onto the
abdomen as a pair of wide bands, one on each
side of the mid-ventral line. There are 4 rows of
stigmata without parastigmatic vessels. The shield-
shaped stomach is smooth, in the posterior half
of the abdomen. Gonads, consisting of a circular
arrangement of club-shaped testis follicles
converging toward the vas deferens at the centre
of the circle, and an ovary containing one egg,
are in the gut loop. Zooids, usually in circles with
the atrial apertures in the centre of the circle, form
rudimentary systems as in Eudistoma and
Polycitorella.

A single large embryo incubates in the brood
pouch, which ts constricted off from the body wall
at the top of the abdomen. The egg apparently
is fertilised at the base of the oviduct. As it
increases in size and moves up the body it projects
from the side of the abdomen and becomes more
constricted from it.

The larva has primarily 3 stalked adhesive
organs in the anterior mid-line surrounded by a
circular fold of the larval ectoderm. As the larva
matures, long radial grooves develop between the
base of this fold and its anterior edge. Subse-
quently the grooves perforate leaving, embedded
in the test around the adhesive organs, a ring of
ectoderm attached by strands to the main part
of the larval trunk. This unusual apparatus is
homologous with the ectodermal ampullae of
other forms. Instead of separate external ampullae
projecting from around the anterior end of the
trunk, a continuous ring of ectoderm projects
forwards.

Adhesive organs have a large conical central
protrusion with the same bulbous appearance as
the central cone of the adhesive organs in Distaplia
(see Cloney 1977), and differing from the more
or less cylindrical, flat-topped, central protrusion
generally found in the adhesive organs of the
Polycitoridae. There also are 4 rows of stigmata
in the oozooid like Distaplia.

Despite this resemblance to larvae of Distaplia,
the relationships of the genus appear with
Polycitorella, which also has particularly muscular
zooids, a constrictor muscle embedded in the test
around the top of the oesophageal neck, calcareous
spicules, and a single embryo brooded at the top
of the abdomen.

THE AUSTRALIAN ASCIDIACEA 2

Cystodytes may be more diverse than is known
at present. However, although several species have
been described, their distinctions from the
apparently wide-ranging species Cystodytes
dellachiajei are not satisfactory. As could be
expected for such a wide-ranging species, the
recorded specimens demonstrate a deal of diversity
reflected in the pigmentation and size of the
colonies. Although at this stage the diversity in
specimens assigned to this species is attributed to
intraspecific variations, it is possible that genetic
studies could establish patterns that result from
speciation. Zooids are remarkably uniform,
although their strong musculature does allow for
a degree of flexibility in their superficial
appearance.

Cystodytes dellachiajei (Della Valle, 1877)
(Fig. 67. Plate 14a-d)

? Aplidium lobatum Della Chiajei, 1841, p. 30,

Distoma dellachiajei Della Valle, 1877, p. 40.

Cystodytes dellachiajei: Hartmeyer, 1912, p. I71,
Michaelsen, 1915, p. 483; 1923, p.28; 1930, p. 501.
Harant, 1929, p. 41. Van Name, 1945, p. 133. Brewin,
1948, p. 119; 1951. p. 104; 1952a, p. 452; 1956c, p.
122; 1958, p. 44; 1960, p. 119. Kott, 1954, p. 154;
1972a, p. 11; 1972b, p. 172; 1981, p. 154. Tokioka,
1950, p. 120. Millar, 1953b, p. 284; 1960, p. 82; 1962,
p. 143; 1963a, p. 713; 1964, p. 166; 1966a, p. 365;
1978, p. 100; 1982, p. 15.

Cystodytes dellachiaiae: Van Name, 1921, p. 360. Berrill,
1932, p, 78. Kott, 1957a, p. 68.

Cystodytes Della Chiajei: Péres, 1948, p. 17.

Cystodyres durus Drasche, 1883, p. 13.

Cystodytes cretaceous Drasche, 1883, p. 18.

Cystodytes draschii Herdman, 1886, p. 137. Van Name,
1902, p. 347. Michaelsen, 1915, p. 484 (draschei); 1924,
1924, p, 286 (draschei).

Cystodytes philippinensis Herdman, 1886, p. 140; 1891,
p. 615. Sluiter, 1909, p. 28. Caullery, 1909, p. 45.
Hartmeyer, 1909, p. 1434. Van Name, 1918, p. 138.

Cystodytes aucklandicus Nott, 1892, p. 323.

Cystodytes perspicuus Nott, 1892, p, 326.

Cystodytes violaceus Van Name, 1902, p. 348. Harant,
1925, p, 3.

Cystodytes ceylonensis Herdman, 1906, p. 334.

Cystedytes hapu Monniot and Monniot, 1987, p. 64.

DISTRIBUTION

New Recorps: Western Australia (Port Hedland,
WAM 1013.83; Recherche Archipelago, WAM 149.75;
Shark Bay, WAM 827.83; Cervantes Reef, WAM 194.87:
Houtmans’ Abrolhos, WAM 386.75 825.83 200,88
204.88; Dongara WAM 1011-2.83; Cockburn Sound,
WAM 8.75 865.82 817.83 919.83 1010.83). South
Australia (Great Australian Bight, QM GH2382;
Spencer Gulf, QM GH4404; St Vincent Gulf, QM
GH2401-2). Tasmania (d’Entrecasteaux Channel QM
GH9996), Victoria (Portsea, QM G11922), New South
Wales (Jervis Bay, QM G10019), Queensland (Capricorn

179

Group, QM G9481 G9596 G9890-3 G9895 G9897-9
G9901-7 G9922 G10017-8 G10033 GH3478-9 GH3816
GH4383-4 GH4412-8 GH4443-6 GH4476; Lizard I,
GH3118 GH3826).

Previousty RecorpeD; Western Australia (Dampier
Archipelago — Millar 1963a; Shark Bay — Michaelsen
1930; Cockburn Sound — Michaelsen 1930, Kott 1957a;
Albany — Kott 1954 1957a), South Australia (Great
Australian Bight — Kott 1972b; St. Vincent Gulf -
Kott 1972a). Tasmania (Maria |, — Kott 1954). Victoria
(Port Phillip Bay — Millar 1966a; Barwon Heads
Millar 1966a). New Zealand (North, South and Chatham
Is — Nott 1892, Michaelsen 1924, Brewin 1948 1951
1952a 1956c 1958, Millar 1960 1982). New Caledonia
(Monniot 1988). Palau Is (Tokioka 1950). Philippines
(Herdman 1886, Sluiter 1909, Van Name 1918), Fiji(Kott
1981). Tahiti (Monniot and Monniot 1987), Sri Lanka
(Herdman 1906), West Indian Ocean (Mozambique
Millar 1962), Mediterranean (Della Valle 1877, Drasche
1883, Harant 1925 1929). Eastern Atlantic (West Africa
— Michaelsen 1915, Millar 1953b, Peres 1948, Canary
Is Hartmeyer 1912; Azores — Michaelsen 1923).
Western Atlantic (Bermuda — Van Name 1902; Brazil
— Herdman 1886; Millar 1978; Patagonian Shelf —
Millar 1960; Virgin Is — Van Name 1902). Eastern
Pacific (California — Van Name 1902).

The species is not confined to the tropics, It extends
around the temperate coast of Australia, and south to
the Patagonian region in the eastern Pacific. In the
Atlantic it extends north to the Azores and Canary Is.
There are two surprising gaps in the recorded range —
the species is not known from either the western Pacific
north of the Philippines, or from South Africa. It could
be expected to occur in those locations, The species also
has a wide depth range, from the intertidal zone down
to 736m (off Brazil: Herdman 1886).

DESCRIPTION

EXTERNAL APPEARANCE: Colonies are cushion-
shaped to large investing sheets of translucent,
firm, gelatinous test, through which patches of
white — the capsules of saucer-shaped calcareous
spicules up to 0.8mm in diameter — can be
detected. In one colony from South Australia (QM
GH2382) small spheroidal spicules in the test
surround the top of each of the capsules. Living
colonies that are white, through pink to purple
(‘auricular purple’: Ridgeway 1886) become glassy
and transparent to pinkish-brown, and cloudy
pink in alcohol preservative. Those grey-black,
red-brown and ‘dragon’s blood red’ (Ridgeway
1886) when living, are grey-greenish-black in
preservative. Morphological differences are not
associated with the different colours (see Remarks,
below).

Zooids are evenly spaced, in circles of 4 to 8,
with their atrial apertures in the centre of the circle.
This arrangement is not easy to see in most
contracted, preserved colonies, especially as the
zooids usually are withdrawn away from the

180 MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 67, Cystodytes dellachiajei: a, zooid partially relaxed (QM GH4413); b, zooid contracted, egg half way
up abdomen (QM G9902); c, dorsal part of pharynx, showing last row of stigmata on each side turning posteriorly
along the mid-dorsal line (QM GH4413); d, immature larvae (QM G5478); e, maturing larva (QM GH3826);
f,g, large embryos before perforation of ampullary fold (WAM 165.75); h,i, larvae with 5 adhesive organs
before and after perforation of ampullary fold (QM G9898). Scales: a, 0.5mm; b,c, 0.25mm; d-i, 0.1mm.

THE AUSTRALIAN ASCIDIACEA 2

surface into the calcareous capsules in the middle
to basal part of the test. The test has a smooth
and even surface, Pigment particles are concen-
trated in the middle layer around the capsules and
between the crowded bladder cells (which occur
throughout the firm test), The branchial and atrial
openings of the zoos are 6-lohed and do not
protrude from the surface. The capsules are usually
vertical, but occasionally are oblique or even
recumbent. In some of the colonies (e.g. QM
{7H2382) the surface is depressed in the centre
of each circle of zooid and forms an incipient
cloacal cavity into which the atrial apertures open,

InteRNAL Sreucrure; Zooids are muscular.
with numerous but fine longitudinal bands from
each of the siphons, Those that extend from the
facing sides of the siphons cross one another on
the sides of the thorax, Vhere are at least 20
longitudinal bands from cach siphon, and also
numerous fine transverse muscles, Sphincters are
around the base of each siphon. The longitudinal
muscles extend onto the abdomien as 2 wide, strong
bands, one on each side of the ventral mid-line.
They terminate abruptly at the posterior end of
the abdomen. A circular evagination of the body
wall around the top of the oesophageal neck
contains the circular muscle embedded in the test.
The test is constricted at this point to form the
narrow canal between the thoracic and abdominal
cavities.

The large number of muscies confers great
flexibility in the ways these zooids contract,
affecting the relationships and relative length of
parts ol the body including the siphons. The
abdomen is especially affected. often being bent
up alan angle to the thorax, and the two parallel
limbs of the gut loop are often distorted away
from the parallel arrangement they display in the
relaxed zooids, Zooids are up to 4mni long when
extended, Siphons (especially the atrial siphon)
vary in length with contraction, sometimes being
particularly long. Six lobes border cach aperture.

Twelve branchial tentacles arise trom the edge
of a narrow muscular velum just anterior to and
alternating with a circle of 12 more robust tentacles
of equal length. The neural gland has a simple,
anteriorly oriented opening lying in a narrow
prebranchial area. An extensive unperforated
pharyngeal area exists both anterior and posterior
to the stigmata. Dorsal languets are long and
pointed, There are about 25 stigmata in each of
4 rows, In one glassy, transparent colony and in
a grey-black colony. with relatively relaxed zooids,
the fourth row of stigmata was turmed posteriorly
along each side of the dorsal sinus, It was not

L&I

observed in all colonies and is either a variable
phenomenon or obscured by contraction.

The gut loop is about the same length as the
thorax. The smooth surfaced shield-shaped
stomach is at Jeast halfway down the abdomen,
although this is not apparent in any bur relaxed
zooids, There is a short mid-intestine, but na
posterior stomach. The rectum originates in the
descending limb of the gut loop and the bilabiate
anal opening is at the base of the atrial cavity.
Esch lip of the anus has about 5 small papillae
along its border.

The testis consists of a dome-shaped muss of
up to 18 club shaped follicles converging to the
proximal end of the vas deferens in the centre
of the more or less flat side of the dome on the
right side of the abdomen. Occasionally a large
ovum ts on the right side of the gut loop, When
testis follicles are not well developed, the vas
deferens loops posteriorly and curves around the
circumlérence ol the ovum, when present, before
extending anteriorly more or Jess parallel to the
rectum. However, the yas delerens does not loop
posteriorly when the testis follicles are mature,
as the duct is stretched over the outside of the
swollen follicles,

The large ovum probably is fertilised at the base
of the oviduct. The embryo increases im size as
it moves up toward the tap of the abdomen,
protruding from the body wall as it goes. As it
increases in size the embryo in its brood pouch
is separated from the upper part of the abdomen
by an increasingly narrow constriction. Occasion-
ally a second, but much smaller embryo in a
secondary brood pouch, is separated from the
primary one by a constriction (QM G9898),

In specimens from Heron |, ova are in the
abdomen in July and August. and embryos in
April (QM GH3478), July (OM GH3816), August
(QM GH9895 GH9S98) and October (QM
GH4384), and also in April at Lizard 1. (QM
G9905). In South Australia larvae are present in
March (OM GH2382), Gonads are absent from
some specimens callected in March and Sep-
tember, although mature testes are in some
collected in March and August. Lt is difficult to
deduce the breeding pattern, despite the large
number of specimens available. In the tropics there
scem at least 2 breeding seasons, autumn and
spring. The species is probably protandrous,

The larva is large. the trunk from 0,75mm te
1.2inm long and sometimes even deeper. There
dre usually 3 adhesive organs in the anterior mid-
line. In two specimens from North West Reef,
Capricorn Group, one purple and gne reddish
brown and another purple one trom Wislan Reel

182

(QM GI899 GARGS CGH43K4) there are 4 to 7
adhesive organs. Other colunies ol all colours have
larvae with the usual 3 adhesive organs. These
larvae all have the characteristic ectodermal ring
around the adhesive organs. They have 4 rows
of stigmata.

Remarks: Chis species has always been poarly
described, owing to the marked contraction of the
strong body muscles, The zooids are dilficult to
narcotise, and in the newly cccorded material (rom
the Capricorn Group which were all nareotised
(menthol) betore fixation, only one specimen (QM
GH4413) has the whole zooid, including the
thorax, extended. Herdman (1886) refers to ‘small’
and ‘nol very numerous’ stigmata, and “exceplion-
ally long and numerous’ branchial tentacles
(Herdman, 1886, p. 136), None ol these obser-
vations could be confirmed in the course of the
Present study, Similarly, Van Name (1945, p. 133)
incorrectly believed embryos were incubated in the
atrial vavity, and the longitudinal museles spread
out over the sides of abdomen in a thin layer.

The interpretation of the colour variations. in
this species is a problem. Ihe 3 most commonly
ocourring types are those with glassy transparent
test, both living and in preservative, Which usually
form rather small cushions never more than lem
in diameter; chose with a deep purple or ‘cinnamon
rufus’ Or ‘dragon's blood red" (Ridgeway 1886) test
which form rather larger cushions up to 2em in
divmeter, und are a cloudy brownish pink in
Preservative; and those that are grey-black both
living and in preservative that sometimes form
more extensive colonies. However, intermediate
forms do occur small light prey colonies,
transparent pink ones, and extensive sheets of
purple colony. Variations occur in the number ol
Jarvul adhesive organs and in the size and shape
ol the larval trunk, but these eannot be correlated
with any classification based on the colour or size
ol the colony. No other variations in 7ooid
morphology were observed. Further, the different
colour yuriints occur sympatrically throughout
the wide range set ont above, They could either
be indicative of genetic diversity in this cosmo-
politan species: or metabolic colours relating to
habitat or dict of some combination of these
ductors.

The small spheroidal spicules that Tokioka
(1950) used to separate Cysrodpres philippinensis
Herdman, 1886 trom the present species occur also
in a Specimen from South Australia (QM
()}H2382).

Without uny indication of how each is related
lu previously recorded material, or lo one another,
Mansiat (F., 1988) hus deseribed 7 new species

MEMOIRS OF THE QUEENSLAND MUSEUM

al Custudyres [rom New Caledonia. These species
hiave bean determined on the busis of colour, the
presence or absence of systems, the course of the
proximal part of the vas deferens, the number of
testis follicles, the numbers of siphonal lobes, the
position of the brood pouch, the length of the
larval trunk. and the number of larval adhesive
organs.

In the Australian material examined in the
course of the present study the same range in each
ol these characters exists as that found in the New
Caledonian species combined. However, the same
combinations have nat been found. Specimens
trom the Capricorn Group, one coloured “toffee
apple’ (Ridgeway [886; QM G989) and two purple
(QM G9895 GH4384), have from 4 to 7 larval
adhesive organs and the length of the larval trunk
in only a single colony ranges from 0,9 to 1.2mm.
Dark violet colonies from South Australia (QM
GH2382) have up to 20 male follicles. as do some
from the Capricorn Group (QM GH3471)
coloured ‘dragons blood red’ (Ridgeway 1886).
Generally, however, the number of testis follicles
Appears to increase with the size and robustness
of the colony. The sive of the testis also affects
the curve of the proximal part of the yas deferens,
which in some ol the Australian specimens is
markedly looped, but runs a straight course when
the testis follicles are expanded. Its course is also
affected by contraction of the yoo and the
maturation of the ovum,

The other character that F, Monniot (1988) has
invoked to justify the erection of new species in
thiy genus is the position of the brood pouch,
Cystodyptes fiuscus, C. punctatus and C. violutine-
ius ace said to brood their larvae at thoracic level,
while in C, amecosuy the brood pouch is said to
be opposite the stomach, In fact the brood pouches
of the first two species appear to be in the usual
position at the top of the abdomen, and in the
latter species (with tts brood pouch level with the
stomach) the embryo is al an early stage of
development. and no doubt will move anteriorly
before it Completes it — as the embryos in the
present collections have heen observed to do.
Monniot appears to have overlooked the fact that
the anal opening ts al the posterior end of the
atrial cavity. A more anterior position is an
artefact resulting from distortion of zooids.
Vurther, in this genus no incipient brood pouch
develops independently of the embryo as in
Holozoidae. In Cysiedies the egg apparently is
fertilised at the base of the oviduct, and increases
in sive.and maturity as if moves up the abdomen.
Jt protrudes more and more from the body wall
as it does so, until, al the top of the oviduct it

THE AUSTRALIAN ASCIDIACEA 2

i8 separated trom the body wall by a sharp
constriction — but never by a narrow stalk.

It is possible that the material on which Monniot
(F,, 1988) erected these new species of Cysrod)tes
wus inadequate to identify intraspecific yariation
— only one colony of CL punerats had larvae,
and these are al u early stage of development;
the description of C. fuscus is based on a single
colony, and that af C. miueasus on only 3. Lis
not impossible that new, including genetic, data
could in due course, establish an objective basis
on Which to separate certain Pacific and Australian
populations of Cprsrod\res from C. dellachiajet.
However, currently it is not possible, Cypytadytes
hapuy Manniot and Monniot. 1987 has oo
characters jusuifing its separation trom the present
Species,

Genus Polycitorella Michuelsen, 1924

Type species: Polveirorella mariae Michaelsen,
1924

Palyciorella contains species with calcareous
spicules in the test, zooids with more than 4 rows
of stigmata, a moderately long oesophageal neck,
gonads in the posterior end of the abdomen. 6-
lobed branchial and atrial apertures (each opening
separately to the exterior), outer longitidinal
muscle bands that extend the whole length of the
vooid and an inner layer of circular muscles, The
test is firm, rigid and packed with bladder cells.
Zooids are usually arranged in circles to form
rudimentary systems as in Cysrodvres and
fudistoma.

An unusual circular constrictor muscle is
around the outside of the zooid at the top of the
nesophageal neck as in Cystedytes. This muscle
is completely embedded in the test which at this
level partially separates the cavity in which the
zooid js contained into an upper thoracic and a
lower abdominal compartment. This constrictor
muscle is almost completely separate from the
fooid, its attachment to it being only tenuous.
and often is found completely isolated from the
rooid — left behind in the test when the zooid
contracts. The sooid musculature ix strong and
eooids are strongly contractile, often being found
with the abdomen bent up against the thorax as
in Cysrodpres. On contraction, zooids withdraw
{rom ihe surface as in other genera of Polycito-
ridae, Contracted zooids are often found in the

abdominal test compartment in the lower half of

the colony (as they are in Cystodytes),
Michaelsen (1924) reported specific organs for

the formation of spicules on each side of the upper

part of the ocsophageal neck, These were nol

183

detected in any of the specimens examined in the
course of the present study. although in many an
oval mass of crowded, small spicules is embedded
in the test at each side of the posterior end of
the endostyle, These may be spicule-forming sites
as are the lateral argans of the Didemnidae.

The genus resembles Polpettor in its numerous
rows of Sligmata, position of the gonads,
separately opening 6-lobed apertures, and its
larvae with median adhesive organs and lateral
ampullae. It is distinguished by the constrictor
muscle and the calcareous spicules in the test. Ihe
spicules resemble those of the Didemnidae
although no direct phylogenetic relationship is
implied.

A single embryo is brooded in a pouch that
projects from the top of the oesophageal neck
Larvae are known for Polveitorel/la coronaria
Monniat, 198% (> P. marive: Millar, 1963a) and
P. orientalis nysp. (> Po mariae: Monniot, 1988)
They have a large trunk, ectodermal ampullac,
and wide adhesive organy on relatively long stalks.
The adhesive organs resemble those of Cysrodyres,
the axtal protrusion constricted basally to form
a wide mushroom-shaped conical protrusion
resembling the axial cone of Diytaplia rather than
the flat-topped cylinder of Pelyeirar and
Eudistoma.

The general shape and contractibility of the
zooids, their arrangement in circular systems, the
firm, rigid test packed with bladder cells, the
cireulat ubdominal muscle, the brooding of a
single embryo at the top of the abdomen, the
capacity to form calcareous spicules, and the shape
ol the larval adhesive organs, suggest a relation-
ship with Cystadyres, Pelycitorella is distinguished
by its more numerous rows of stigmata, and the
shupe of the spicules which ure stellate rather than
flat and saucer-shaped

Previously Pulvciorella was known only trom
single colonies (rom the Indian and western Pacitic
veeans — the Gulf of Suez. South Atrica, the
North J, (New Zealand) and Port Phillip Bay
(Victoria). The 2 species described below are the
only ones for which numerous specimens are now
available, and these indicate a high degree of
intraspecific diversity. The known species appear
closely related,

The genus appears confined to the Indo-West
Pacific, In addition to the 2 Australian species.
the folluwing até known, but have not heen
recorded trom Australia:

Polyciturella haspitiolixs (Savigny, 1816) >

Exeoelium hospitialum Savigay, fram the Gulf

of Saez resembles Polveitarella orientalis n.sp.

184

in the distribution of its spicules, but has fewer
(6) vows Of stigmata.

Polyeiterella mariae Michaelsen, 1924 lrom the
North |, New Zealand is a stalked colony with
debris attached to the stalk, without circular
systems, and with small (0.018 to 0.025mm
diameter) spicules (ZMC 2.1.1918).

Polyeitorella pallida Millar, 1962 from South
Africa has a large, sessile colony. stellate spicules
up to 0.06mm diameter, bul ¢ooids are not
arranged in systems.

Polycitarella perest Plante and Vasseur, 1966 from
Madagascar has brick-red colonies and spicules
up to 003mm with fat-ended rays.

Polyeitorella seroensis Nishikawa, I980) from
Japin has unusual disc- shaped spicules as well
as stellate ones.

Polycitorella coronaria Monniot, 1988
(Fig. 68. Plate tde)
Polyctorella coronaria Monmiot, 988, p, 228.
Palyeitorella marine: Millar, 19634, p, 71b.

DistRimution

New Recorus; Western Australia (Northwest Cape,
WAM 828.83; Shurk Bay, WAM 8189.83 OM GA2/43-
4; Abrothos, WAM 820.83 OM GH2/43, WAM 824.83
626,83 829.83 191.88 2146.88 220.88 222.48 233.88:
Cervantes 1, WAM 194.47; Cockburn Sound, WAM
842.83 OM GA2125, WAM 844.83 OM GH2/24). South
Australia (Great Australian Bight, Ward |, QM GH924
GH2377, NTM E33; Pearson 1... OM GH1313).

Previousry Recorprp, South Austral (Great
Australian Bight — Monnjot, F. 1988), Victoria (Port
Philip = Millar 19634),

The species is recorded from 3 to 190m. It is common
Of southern and western Australia as far north as
Northwest Cape, It has not yet been recorded trom
tropical waters of the western Pacific, although,
strangely, Monniot (F,, 1988) described i (from a single
colony from the Great Australian Bight) in a paper on
ascidians from New Caledonia.

The numerous specimens examined in the present
study has made it possible lo more Sully document the
species; and to emphasise one of its main charactenstics

the regulat cushioa-shape of the larger specimens

which, despite the species name, was oor altogerher
uppirent from the single creseentic colony on which the
original desenplion was based. Sadly, despite the large
number of specimens already available in Australian
museums, the holovype af this commen Australian
species is lodged in the Museum National d'Histoire
Naturelle, Paris, having been donated by the US
National Museum (see Monnial, F., 19S),

DESeRIPTION

ExtpRNAL Arenarancre Most of the recorded
colonies are massive circular, oval or long and
slightly convex cushions up to 6em it maximum
dimension and aboul 3cm high. Large colonies

MEMOIRS OF THE QUEENSLAND MUSEUM

are fixed by the whole ol (he basal surface. When
ais curved over rubble er other substrares the
whole colony becames dome-shaped. Smaller
colonies usually have a thick stalk, up to 3cm long,
with a slightly wider almost spherical to dome-
shaped head. The stalk is progressively lost as the
colony increases in size, the head increasing in
diameter and becoming flatter on the upper
surface.

Colonies show considerable colour variation,
which is affected by the distribution of dark
spherical pigment cells and white calcareous
spicules, ‘The upper surface is white. grey or black
with black or white patches where the apertures
open to the surface. The lower half of the colony
is always a dirty white colour, Pigment cells are
Present in the test of the upper surface, and
sometimes in the thin layer that curves in. to line
each siphon, They are present also around the
zooid compartments in the test, Pigment cells are
also scatlered sparsely in the internal test of the
upper part of the colony, becoming more sparse
toward the base, White calcareous spicules. are
always in the external test of the stalk and usually
(but not always) in the basal half of the colony,
hey are also in the internal test of the lower half
of the colony uround the abdominal parts of the
vomds. Spicules are usually mixed with pigment
cells in the surface layer of test Over the upper
part of the colony making it grey, The upper part
of the colony is black if spicules are absent from
the surface test. Spicules are in the surface test
only around the apertures creating a pattern of
white patches where the zooids open to the surface,
Internally spicules are always absent from a chin
layer of test that lines the cavitics containing the
zooids, Otherwise they are either throughout the
internal test, only in patches or jn a layer at the
upper abdominal level, or only in the upper half
of the colony, or absent altogether from the top
half. Spicules are stellate, 0.04 to 0.08mm
diameter, with 5 to 7 conical rays in optical section.
Sometimes mulberry-like spicules with rounded
rays also occur. Oval masses of small, crowded
spicules are sometimes visible at each side of the
posterior end of the endostyle, embedded in the
otherwise spicule-free layer of test that lines the
cavities containing the zaoids, Although no actual
suc connected to the body wall of the zooid was
detected, these oval masses of small spicules
probably are where spicules are generated.

Zoaids are always in evenly spaced circular
systems Of 7 to 10 zooids, the 6-lobed branchial
apertures present in a wide outer circle with the
6-lobed atrial apertures, on the end of relatively
Jung siphons opening in a small tight inner circle

THE AUSTRALIAN ASCIDIACEA 2 185

Fic. 68, Polycitorella coronaria: a, large colony showing arrangement of zooid openings in circles (WAM 844.83);
b-d, outline of various colonies (WAM 818.83 826.83 824.83); e, a section through a system showing zooids
embedded in the test with atrial openings near centre of circle, and branchial openings in the outer circle
(WAM 216.88); f, zooid showing long atrial siphon and oesophageal constrictor muscle (WAM 214.88); g,
posterior end of thorax and contracted abdomen showing detail of testis and vas deferens (WAM 819.83):
h, larva (QM GH1313). Scales: a, 2cm; b-d, lcm; e,f, [mm; g, 0.5mm; h, 0.2mm.

186

sometimes vround a central depressian, Ihe
ventres of the systems are about 5mm away trom
one unother, The atrial apertures are on long
siphons that reach into the centre ol the circle
and, When open and extended, the anterior atrial
lobes are longer thun the posterior ones R]
phenomenon commonly observed where atrial
siphons open in the centre of ineipient cireular
systems (see Pucdistoma)

‘The test is firm and, when spicules are absent,
it is glassy, transparent and packed with bladder
vells, Zooids are uccommodated in large, rigid
hourglass-shaped compartments in the firm test,
the thoraci¢ and abdominal section of each
compartment separated by the lest constriction
with its embedded constrictor muscle,

From the condition of the vooids, apparently
the whole zooid withdraws from the surface on
vontraction. The constrictor muscle sometimes has
contracted around the top of the abdomen hefore
the thorax is withdrawn into the abdominal
chamber, and it is assumed that this usually would
occur in life. In some of the material examined
however, contraction has been $o Violent that the
zooid has lost its attachment to the muscle, and
bas completely withdrawn into the abdominal
compartment. In other specimens the contracted
consirictor muscle has strangled the thorax at
various points along its length as it was being
withdrawn into the abdominal compartment —
sometimes contracting around the top ol! the
thorax and strangling the zooid behind the siphons
or occasionally catching only the two siphons.

InnrkwaAr Srrucrure: Test compartments
containing the zooids are about one to 2em in
total length. It is assumed that living, zooids
completely fill these spaces. The thoray and
abdomen appear of almost equal length in their
extended condition, Contracted zooids are from
4to 8mm. The branchial aperture is terminal, and
the atrial aperture extends obliquely on the end
of its long siphon into the centre of the circular
system of zooids, Externally there are ubout 20
longitudinal museles on each side of the thorax
and these continue in wide bands along each side
of the abdomen, A layer ol inner circular muscles
is present beneath the longitudinal ones on the
thorax, Sphineters surround each aperture, and
the constrictor muscle (described above) is at the
top of the abdomen,

‘Twelve long branchial tentacles alternate with
shorter ones i a single circle at the base of the
branchial siphon, although difficult to count,
There are 10 to 20 rows of 1S to 30 stigmata,
The number of stigmata appear to increase with

MEMOIRS OF THE QUEENSLAND MUSEUM

the size of the colony, Dorsal languets wre
triangular and present in the mid-line,

The oesophagus is verticul in partially relaxed
zooids (WAM 214.88) and opens into the long
stomach in the posterior half to one-third of the
abdomen, The stomach wall is smooth eaternally,
and has papillations internally. It is not folded.
There is ashort dugdenal area and a small rourided
posterior stomach constricted from the rectum in
the pole of the gut loop.

When mature. the testis is large. consisting of
a mass of numerous short follicles that project
out from the loop of the gul. The vas deferens
arises from the center of the mass and loops out
acound the outside of the anterior half of the mass
before it extends anteriorly up the oesophageal
neck to the atria] cavity. Only a single egy at a
time was found outside the male follicles.

South Australian specimens had mature gonads
and Jarvae in March (QM GH1313) and April.
In the Western Australia material they were also
mature in some (but not all) specimens trom
Cervantes and from the Abrolhos collected in
March and April. A large embryo is in the oviduct
at the top of the abdomen in one colony only
(QM GH2377). Larvae also are present in the
brood pouch at the tap of the oesophageal neck
in the specimen from Port Phillip (Mitlar 1963:
BM85._11.20,48). The larval trunk is 1,1 to 1.2mm
long and has 4 pairs of lateral ampullac alternating,
with the 3 median adhesive organs at the anterior
end.

Remanks: Chis species is vartable in colour
pattern (though not in colour) and in the shape
of the colony, The colour is always some
combination of black and white the former
varying according Lo the distribution of the black
pigment cells, and the latter accarding to the
distribution of the calearcous spicules. Variations
in the shape of the colony depend on its size und
the nature of the substrate.

Polveitorella coronaria is ceadily distioguished
from previously described species by the arran-
gement of its zooids incircular systems emphasised
by the colour patterns in the colonies, Further,
the spicules of the present species are larger chan
those of the New Zealand species P. mariae, which
have # maximum diameter of 0.025mm, Spicules
of P. pallida from South Africa are larger (tu
006mm diameter) and are similar to those of the
present species. Millar (1963a) observed the test
vonstricuion between the abdominal and thoracic
compartments, but overlooked the muscle
enibedded in tt. Polveitored/a mariae: Millar, 1963a
from Pert Phillip (Victoria) has spicules of
O.M6mm diameter, and although Millar observed

THE AUSTRALIAN ASCIDIACEA 2 187

only mulberry-like spicules with rounded rays, the
specimen probably belongs to the present species.
Similar spicules do occur in specimens [rom
Western Australia, although they are mixed with
stellate ones, Larvae of the Victorian specimen
are identical with those from South Australia,

Polycitorella orientalis has smaller colonies, its
largest spicules are Jess than half the size of those
in the present species, zooids are only occasionally
grouped into small systems, and the larval trunk
is almost twice the size of that of the present species
(sce F. Monniot 1988).

Polycitorella orientalis n.sp.
(Fig. 69. Plate 14f,g)
Polycitorella mariae: Monmot. F., 1988. p, 227.

Distriaunios

Tyer Locaimy Queensland (Swain Reefs, under
ledge 8m, AMPI 133, coll. N, Coleman, 9.7.74, holotype
QM G9477, paratype QM GH4420; coll. Watson
10.10.74, paratype QM GH4420),

Forrnune Recor; Queensland (Heron I, specimen
destroyed for analysis: Fredrickson 197%; Coral Sea —
Monniot. F.. 1988),

DeseripTion

ExrernAL APPFARANCE The specimens have
relatively small (about lcm diameter) rounded
heads on a short stalk of slightly less diameter,
The whole colony is 1 to 2.5em high. A larger
colony (QM GH4420) of 2cm diameter is a flat
cushion without a stalk, Zooids open onto the
upper surface of the head on well separated
shallow, oval prominences. Some are grouped into
2- or 3-zo0id systems, their atrial apertures
adjacent to one another. The zooids converge into
the centre of the head and down into the stalk,
almost to the base.

In life colonies are cream, pale yellow or green,
but when preserved. they always are cream.

Calcareous spicules are in the surface layer of
test of the head and the stalk. Internally, they
are only sparse at thoracic level and in the stalk
they form a sheath around each abdomen. They
are absent from the test between these abdominal
sheaths. Spicules are 0.025 to 0.035mm in
diameter. They vary from stellate, with 5 to [5
pointed or flat-ended rays in optical section, to
mulberry-like spicules with rounded rays, and
spherical ones made of many thin radially
arranged rods.

INTERNAL Srructure: Contracted zooids are
about Smm long. The apertures are 6-lobed, both
on short siphons at the anterior end of the body.
In addition to sphincters around the apertures,
the thoracic musculature consists of longitudinal
bands overlying a layer of circular muscles.

Fic. 69, Polveirorella orientalis nsp. (holotype QM
G9477); a, colony; b, zooid showing circular muscle
embedded in the test around top of oesophagus: c.
stellate spicules. Scales: a, 2mm, b, !mm; ¢. 0,02mm.

188

Longitudinal bands extend along the abdomen in
a pair of ventral muscles, The constrictor muscle
is embedded in the test around the upper part
of the oesophageal neck. There are 10 rows of
about 20 long stigmata.

The thorax and abdomen may be of equal length
in relaxed zooids. However, in these variously
contracted specimens the abdomen is sometimes
shorter and sometimes longer than the thorax. The
stomach is in the posterior third of the abdomen.
It has fine longitudinal glandular ridges in the
internal lining, but it is not folded. A mass of
crowded, short, pyriform, male follicles is in the
gut loop. No eggs were seen in the newly recorded
material.

Larvae of this species were in specimens from
the Coral Sea (Monniot, F. 1988). The larval trunk
is 1.9mm long, and the tail barely reaches to its
anterior end. There are 4 pairs of lateral ampullae
alternating with the 3 adhesive organs in the
anterior mid-line, an ocellus and otolith.

Remarks: Polycitorella orientalis is distin-
guished from P. coronaria by its small colonies,
its colour (lacking the dark pigment of the latter
species), its small systems that occur only
occasionally, its relatively small spicules with
slightly longer arms and its appreciably longer
larval trunk, Although the now destroyed
specimen from Heron I. had a preponderance of
mulberry-like spicules like the specimen of P.
coronaria from Port Phillip Bay (> P. mariae:
Millar 1963a), the spicules in the Heron I. colony
were the same size as those of the present species,
and the colony form and pigmentation were also
similar.

Monniot (F. 1988) believed P. mariae: Millar
1963a (from Port Phillip Bay — not the Philip-
pines) was a synonym of her specimen from
Chesterfield Is in the Coral Sea. However, the
spicules of the Victorian specimens are larger and
the larval trunk is shorter (1.2mm) than that of
the Chesterfield Is specimen (1.9mm). The
Chesterfield Is specimen appears conspecific with
the present species, having similar yellow colonies,
and small spicules, F. Monniot (1988) also thought
that the Chesterfield Is specimen was a synonym
of the New Zealand P. mariae Michaelsen (ZMC
2.1.1918). However, although the New Zealand
species has a similarly stalked colony, its stalk
is longer and covered with adherent foreign
particles, its spicules are smaller than those of the
present species and they are all stellate with conical
rays.

Polycitorella pallida from South Africa like P.
coronaria forms larger colonies and has larger
spicules.

MEMOIRS OF THE QUEENSLAND MUSEUM

Genus Eudistoma Caullery, 1909
Type species: Distoma rubrum Savyigny, 1816,

The genus has small, characteristically polyci-
torid zooids with a long oesophageal neck, and
gonads and stomach at the posterior end of the
abdomen. The atrial and branchial apertures are
6-lobed, Longitudinal muscle bands on the thorax
extend in one or 2 bands along each side of the
abdomen. An inner layer of circular muscle lies
beneath the longitudinal ones on the thorax. There
are 3 rows of stigmata. The anterior row contains
more stigmata than the other two, and its dorsal
end usually curves anteriorly along each side of
the mid-dorsal line. The stomach is always small,
shield-shaped and smooth. A long duodenal area
is posterior to the stomach, and usually an oval
posterior stomach at the distal end of the
descending limb of the gut loop. The gastro-
intestinal gland is well developed. The anus opens
between the second and third rows of stigmata.
As in other genera of the Polycitoridae, zooids
withdraw into the base of the colony when
disturbed.

With rare exceptions (when it occurs in the distal
part of the oviduct), fertilisation takes place in
the atrial cavity. Larvae are small, with a larval
trunk only occasionally more than Imm long.
They have 3 stalked adhesive organs in the vertical
mid-line anteriorly. A fairly wide tuft of columnar
cells project from the centre of a deep ectodermal
cup. Ectodermal ampullae usually alternate with
the adhesive organs and often also are along each
side of the anterior end of the trunk. Ectodermal
vesicles, originating as terminal expansions of
thread like extensions from ectodermal cells, are
often present in the larval test (see Annotated
Glossary: larvae).

Sand and other foreign particles including plant
cells are often embedded in the test, sometimes
confined to the central or basal part of the colony,
but sometimes throughout the test. In most species
faecal pellets are in the test. This may result from
the contraction and withdrawal of zooids from
the surface causing ejection of faeces from the
short thorax. Several species also have unusually
large spherical cells embedded in the test.
Michaelsen (1930) believed these symbionts,
although this is established only for E. amplum.
The test is often brightly pigmented and usually
opaque in living specimens.

Zooids of most species are in rudimentary
circular systems with the atrial apertures in the
centre of the circle. In these species the atrial
siphons are long. When systems are absent the
atrial siphons are shorter and more or less the

189

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MEMOIRS OF THE QUEENSLAND MUSEUM

190

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191

THE AUSTRALIAN ASCIDIACEA 2

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192

same length as the branchial siphons, Both siphons
usually have a distinct sphincter muscle.

Eudistoma is distinguished from Sigillina
which also has only 3 rows of stigmata — by the
long oesophageal neck, much smaller zooids,
absence of a brood pouch, smaller embryos
incubating in the atrial cavity, and absence of the
epicardial extension in the vascular stolon. The
structure of the gut with its long duodenal region,
oval posterior stomach and small, smooth
stomach, is particularly stable throughout
Eudistoma and constitutes a further reliable
distinguishing character, Although the larval
adhesive organs have a more or less flat-topped
central protrusion of columnar cells, it is always
cylindrical and never forms a long ridge or
platform as it does in Sigillina.

The genus is an homogenous one, and zooids
are difficult to distinguish from one another. They
are invariably found contracted, causing various
distortions of the gut and abdomen. Hastings
(1931) observed that kinks in the gut, used by
many authors to distinguish species, are of little
value as taxonomic characters. While the oeso-
phagus becomes wrinkled on contraction, the
rectum, containing faecal pellets, is variously
kinked and sometimes looped in contracted zooids
of all species. Characteristics of the colony — its
shape, colour and test inclusions — afford more
reliable characters for species identification than
the zooids themselves. Unfortunately the colour
is lost in preserved material and test inclusions
have not always been recorded. The difficulties
encountered in characterising FEudistoma spp.
cannot be over-emphasised, but to some extent
at least, these will be alleviated if records are kept
of the colour and general appearance of living
colonies.

In a few cases species share conspicuous
characters that suggest a phylogenetic relation-
ship. Thus Eudistoma angolanum, E. carnosum
n.sp., E. reginum n.sp., with E. magalhaensis from
the Magellanic region, form a species group
characterised by the localisation of pigment in
pockets in the larval trunk haemocoele, and the
formation of distinct, albeit rudimentary, cloacal
cavities. Also E. globosum, E. laysani and E.
elongata are possibly related, colonies all having
stalked lobes, and zooids being crowded and not
in systems. Other species groups have not been
identified.

Eudistoma has not been recorded from the
Antarctic, only one species — F. vitreum (Sars,
1851) — is known from boreal waters (see Millar,
1966b), and the genus is most diverse in tropical
waters. Species of this genus are commonly

MEMOIRS OF THE QUEENSLAND MUSEUM

encountered around the Australian continent. The
27 species discussed below include 17 new to
science of which 11 are tropical. Six indigenous
species are known only from temperate waters.
Although a number of the Australian species
resemble some recorded from Africa, they appear
distinct. Sluiter (1909, 1919) recorded 12 species
from the Indo-Pacific that can be assigned to this
genus with confidence. However, in the following
80 years only 2 of these were recorded again,
although a further 5 species were described from
the area. Difficulties in distinguishing species from
one another when only preserved material is
available may have caused this apparent lack of
diversity in the previously recorded material,

Key TO THE Species OF EvbISTOMA
RECORDED FROM AUSTRALIA

1. Systems present ......... 2. ce cee eee eee 2
Systems not present..........+-2++-06- 23

2. Rudimentary cloacal cavity present
Rudimentary cloacal cavity not present ...5

3. Sand absent from surface test around
SYSEOTNG aiatately el gata bin ae He ple 2 EM 4
Sand present throughout ....£ angolanum

4. Cloacal apertures on conical prominences..
Salles Se ae! eves Bs E. carnosum n.sp.
Cloacal aperiures not on conical prominen-
CER ee RG Edel OS E. reginum n.sp.

5. Colonies divided into numerous lobes on
COMMON base... eee see eee eenenees 6
Colonies not divided into numerous lobes on
COMMON HAS ... 6. cee ewe eee eee ee eee 8

6. Sand crowded throughout test...........-
ste Bs Salas she's she 4 set ¢ shvig ree pe E. pyriforme

Sand not crowded throughout test ....... 7

7. Colony lobes top-shaped..... E. gilboviride
Colony lobes rounded, sessile
ey ee en teeeee BE. tumidum n.sp.

8. Large (up to 0.3mm) symbiotic plant cells
presgert.in test: . 0. +sc5 5 die- E. amplum
Large symbiotic plant cells not present in
test va weed eed ohegeareateaiws 9

9. Sand crowded throughout test.......... 10
Sand not crowded throughout test ...... 12

10. Colonies upright cylinders ...............
pea et uaees Bag cess E. bulbatum n. sp.
Colonies not upright cylinders. .

11. Sand present around apertures of ee
tropical species ...... 24004008 E. ovatum

Sand not present around apertures of zooids:
temperate species..... E. sabulosum n.sp.

12. Colony with two-toned pattern in surface
test ....
Colony without two-toned pattern in surface
BEBE 0 ie, soe ing erties shebeerar ent ack’ p rye 14

20.

21.

22.

23.

24,

25.

26,

27.

THE AUSTRALIAN ASCIDIACEA 2

Larval trunk 0.9mm long; temperate species
pedi tae es E. maculosum n.sp.
Larval trunk 0.6mm long; tropical species. .
fel pwltdsing Ser eelweyee op E. tigrum n.sp.
Fusiform and dentritic pigment cells pres-
BME es a gles tak ll alison FE. eboreum n.sp.
Fusiform and dendritic pigment cells not
PEESEM es ara vaca ine oh en afetntabid oan efeyd ect ah 15
Surface test speckled with evenly spaced
vesicles (0.05mm diameter)...........4.
Py libtp ach te dee ees E. incubitum n.sp.
Surface test not speckled with evenly spaced
VESICIED pate hid tte ate ele elles Ale a ele eee 16
Colonies extensive investing sheets ...... 17
Colonies not extensive investing sheets ..18
Test soft and mucus-like ..£. gracilum n.sp.
Test not soft and mucus-like .............
gehen Ft # bE 4 ots E. pratulum n.sp.

. Test bright green both living and in preser-

VALVE’ cancel dy deer Sede E. glaucum
Test not bright green either living or in
PLESELVALIVE yy cae ule eae SESE RA 19
Test bright purple in life; zooids greenish-
black in preservative ...........e0000es
ISU TeONe reee he 4 E. purpureum n.sp.
Test not bright purple in life; zooids not
greenish black in preservative
Colonies with sand embedded in stalk ...21
Colonies without sand embedded in stalk 22
Layer of sand beneath surface test; zooids
reddish-brown in preservative
Bl Pace etek «agli ge bie E. aureum n.sp.
No layer of sand beneath surface test; zooids
not reddish-brown in preservative.......
jeveele ype eee BND TAN SRS E. malum n.sp.
Surface test with conspicuous white suspen-
sion in preservative; zooids not reddish-
brown in preseryative
Fak devg fi Meath Viger ete means E. anaematum n.sp.
Surface test without conspicuous white
suspension in preservative; zooids reddish-
brown in preservative
rr E. muscosum nom, nov,
Colonies stalked ....... 0.0... e eee eee 24
Colonies not stalked
Sand present both in stalk and in centre of
Heat. 552 an a she reked cree ee E. globosum
Sand not present either in stalk or in centre
OE PA an boy ea WA Lo tlne les ge able oe 25
Head long and cylindrical ....£. elongatum
Head not long and cylindrical ...&. /aysani
Colony with embedded sand
Colony without embedded sand
Seed da ng ae Ugle aaalle E. superlatum n.sp.
Sand absent from surface test over anterior
ends of zooids ...... E. constrictum n.sp.

193

Sand not absent from surface test over
anterior ends of zooids ...........4005
Foie oleld sichy sales sin nd E. microlarvum n.sp.

The following species, previously described

from the western Pacific and the Indonesian

region, have not yet been recorded from Australia:

Eudistoma fragum F. Monniot, 1988 from New
Caledonia has a red test, embedded sand, and
a larva with lateral ampullae similar to those
of FE. amplum. However, symbiotic cells have
not been recorded, and the zooids are not
arranged in circles.

Eudistoma glabrum (Sluiter, 1919) has sessile,
cushion-like colonies with a convex upper
surface about 2cm high in the centre. Little sand
is embedded in the upper layer of test and
elsewhere the test contains only crowded faecal
pellets. Zooids are in circular systems. Branchial
and atrial siphons are both long, and the basal
part of the branchial siphon has a wide band
of numerous branchial tentacles in at least 7
rows. About 25 stigmata are in the anterior row,
which extends forward along each side of the
mid-dorsal line. Spherical pigments cells of
about 0.01mm diameter are scattered evenly,
but sparsely, throughout the test. It is distin-
guished from £. malum by its long branchial
siphon and wide band of branchial tentacles
(ZMA TU1281 lectotype).

Eudistoma laysani: Tokioka, 1967a, from the
Palau Is has a similar, although less regular
colony than FE. toealensis Millar, and is further
distinguished by its median rather than paired
larval ectodermal ampullae that alternate with
the median adhesive organs.

Eudistoma loricatum (Sluiter, 1909) from Indone-
sia has a colony similar to £. bulbatum n.sp.
However in F. /oricatum the lobes of the colony
are smaller, devoid of sand over the upper
surface and are attached to common basal test
(ZMA TU1267 lectotype).

Eudistoma miniacum (Sluiter, 1909) from Indone-
sia has flat-topped lobes of variable diameter
arising from a common base, larvae with a long
cigar-shaped trunk (1.2mm long) and 4 median
ectodermal ampullae alternating with the
adhesive organs and zooids in conspicuous
circular systems opening on the upper surface
of the lobe. The lobes have a distinctive
appearance, with a network of pink pigment
cells in the surface test (ZMA TU1268
lectotype).

Eudistoma multiperforatum (Sluiter, 1909) forms

hard, sand-impregnated, bluish-red sheets with
a superficial resemblance to colonies of F.

194

angolanun. The sand is crowded in the lower
half of the colony and spurse elsewhere, Zooids
are large and pink in preservative, not crowded.
not arranged in circular systems, and Jack lony
atrial siphons (ZMA TU809.1-.2 syntypes),
Euclistema sp, alt, angolanun: Vokioka 1967a
from the Palau Is may be conspecilic,

Eudistoma rubrum Tokioka, 1954a trom the
Tokara Is and Fiji (Kott 1981) has almost
spherical, transparent heads with reddish-
orange zooids. The spherical transparent heads
are unusual — resembling Pulveifor more
closely than Fudisronia spp.

Eudistama segmentatum (Siuiter, 1909) from
Indonesia forms upright, cylindrical or conical
lohes arising from a common basal test mass.
The tops of some of the lobes of the Jectotype
appear regenerating, thus accounting for
Variations inthe shape of the Zooid-bearing part.
Zooids in these regenerating colonies ure
apparcntly non-functional juveniles, as they de
nol open to the exterior and no faecal material
is present in the gut. The species is distinguished!
from F. /oricatum and E laysani by its more
juincrous zooids and taller colonies, Constric-
lions Tm the test recorded for this species were
not distinguishable on cxamination of the
lectotype (ZMA T1268 lectotype).

Eudistama stellatum Monniot, 198% tram New
Caledonia apparently resembles E. angelanum
in the field, However, the lather species hag a
larva with more numerous ampullae, The fold
in the stomach described for this species does
nol appear to have wu homologue in the genus.
Vhe larva is like that of F. gilbaviride,

Euclistoma toealensis Millar, 1975 from Indonesia
has rather long cylindrical lobes arising from
a common basal test mass, and a long larval
trunk of 1.016 1.3mm. These colonies resemble
some from Vietnam assigned to E, /aysani by
Tokioka (1967b) Which have the same partially
subdivided, paired larval ectodermal ampullae
and the same posterior extension of the ventral
ampulla as Millar's specimens.

Eudistoma tokarae Tokioka, 1954a from the
Tokara Is has zovids opening on the upper
surface of small upright lobes, and faecal pellets
and abdomina inthe stalk. Minute dark greenish
pigment spots are in the test, and zooids,
Tokioka and Nishikawa (1975) discussed the
possibility thal this species represents juvenile
colonies of EL glaveum. However, both the
yooids and colonies, including the pigmentation,
are different from those of & glakeuwm.
Although the colomes are more like & laysari
and &. ineubitam nsp. the pigmentation is

MEMOIRS OF THE QUEENSLAND MUSEUM

different from both, and /. tekurue appears a
good species, distinguished from others by its
dark pigment cells in the test and zooids.

The following species with 3 rows of stigmata,
Which Were assigned to Polvcitor by Sluiter (L909),
are not members of Budistoma: P. vielaceus(ZMA
TUS14 halotype < Trididenmum sp.). P. signiferus
(ZMA ‘TU808.1 lectotype < Sivi/lina signifera), P.
caalituy (= Mypadistoma deerratunt), and P.
ianthinus (< Exostoma n.gen. fanrhinam), The last
three §pecies ure discussed in this work.

Kudistoma amplum (Sluiter, 1909)
(Fig. 70. Plate [5a)

Polyctter aniplus Stuer, 1909, p, 21, Not Hartinever,
19190 p. 105 (see Hastings. 1931),

Auclisteuna arnplus; Vokioka, 1950, p, 118,

Eudistoma amplam: Vokioka, }967a, p. 121, Millar,
1975, p. 219 (part, not specimen from Toeal with
cloacal cavity =" &. reginum nsp.).

Polyciter discolor Stuiter, 1909, p. 17,

DistRinu nos

New Recoaos: Queenslind (Capricorn Group, QM
111936 7 GU9TT § GH374 GHIS24 GHI352 GHI824
GHI833-4 GH2238 GHI817 GH4421-4 GH4432
GH4442 GH4470 | GH4977 9 GH4500-4 GH4512-7
CHH4562, Green 1., OM G12501; Lizard 1, OM GH4608-
9),

Previousty Reconnre: Palau Is. (Tokioka 1950,
19674). Indonesia (AMA TLT81 type Palveror amplus
Stuiter, 1909; ZMA TUTKS,1-3 svatypes Polveifor
discolar Sluiter., 1909). Philippines (Millar 1975).
Drsecr ievion

EXTERNAL AppeEARANCE: The colony forms
robust Mat-topped cushions to sheets up to 14em
or more in Maximum dimension and about |.5em
thick, with rounded borders. The surface is smooth
und often shiny. Although sand grains are present,
and sometimes crowded in the test, they.are usually
absent from the upper surtace except between the
atrial and branchial openings of each zooid so
that the sand forms a star-shaped or daisy-tike
pattern that emphasises the arrangement of vooids
in circular systems. Sand grains in the surface,
especially around the sooids, are smaller than
those in the remainder of the test. Systems are
about 0.5em in diameter with the atrial apertures
toward the centre of each circle and the branchial
apertures around the periphery. The suriace test
is often (but not always) depressed in the centre
ol the circle and the atrial openings are around
the border of this depression.

The test itself is glassy and colourless, but this
is obscured by the test inclusions. Large, variously
sized (up to 0.3mm in diameter) spherical vesicles
in the test are usually (but not always) crowded
in the surface layer and become less crowded

THE AUSTRALIAN ASCIDIACEA 2

Fic. 70, Eudistoma amplum: a, branchial (outer circle)
and atrial (inner circle) openings of a single
rudimentary system on surface of colony (QM
GH2238): b, embedded green cells clustering around
a branchial aperture (QM G11978); ¢, zooid showing
thoracic muscles and vesicles associated with the
gastro-intestinal gland clustered around the gut (QM
GH352); d, contracted zooid with larva in atrial cavity
(QM G11937); e, larva (QM G11937). Scales: a, |mm;
b, 0.25mm; c,d, 0.5mm; e, 0.2mm.

toward the base. Embedded sand grains become
more crowded toward the base. The spherical
vesicles are eukaryotic algal cells. They are usually
red and shiny in the living specimens, causing the
maroon to ‘aster purple’ (Ridgeway 1886) and
brown of the colony. This sometimes shades to
brownish-yellow (‘gallstone yellow’: Ridgeway
1886) when sand is near the surface. However,
green and red plant cells and sand are often
distributed fairly evenly through the whole

195

thickness of the colony. In preservative vesicles
are cream or slightly cloudy-greenish and
translucent. In one specimen (QM GH4555) the
green cells are cysts containing numerous small
spheres (see E. vitiatum Kott, 1981).

This species very often has Prochloron cells on
the surface of the colony (Kott er a/. 1984). They
are only loosely attached and can be easily wiped
off.

INTERNAL STRUCTURE: Living zooids are
yellow-orange. They are robust, but when
contracted are only about 5mm long. The atrial
siphon is up to 3 times the length of the branchial
siphon. The circular sphincters around each
aperture are not especially strong. Up to 20
longitudinal muscle bands on each side of the
thorax often join one another to form half that
number of bands. They are relatively fine, well
separated from one another, and sometimes are
in 3 or 4 groups on the sides of the thorax. The
circular muscles are more numerous. About 22
stigmata in each row are generally long, becoming
shorter ventrally. Dorsal languets are to the left
of the mid-dorsal line. About 24 branchial
tentacles of various sizes are apparently in 3 circles,
although this is difficult to see.

The small, smooth stomach is near the posterior
end of the abdomen. There is a relatively long,
narrow duodenal area and a long mid-intestine
that curves around in the pole of the gut loop
before entering the rectum. The posterior stomach
(in the mid-intestine) is sometimes rather obscure.
A band of thin-walled spherical, elongate or
irregular terminal vesicles of the gastric gland
surround a section of the gut opposite the stomach.
A kink occurs in the proximal part of the rectum
just posterior to the stomach in these contracted
specimens.

Gonads are maturing in specimens collected in
September but not in January, February or July.
Colonies collected in July are in an active
vegetative phase. One or 2 large larvae are in the
atrial cavity of specimens collected from the
Capricorn Group in July to September (QM
G11936-7 G11971), The larval trunk is almost
Imm long, and the tail winds a little more than
half way around it. The adhesive organs consist
of a small cone of adhesive cells surrounded by
a shallow epidermal cup on a long narrow stalk.
A row of 4 lateral ampullae, bent at right angles,
is on each side of the median row of adhesive
organs. A median dorsal ampulla lies between the
lateral ones, but median ampullae were not
detected between the adhesive organs.

Remarks; The species is distinguished by the
spherical plant cells and sand embedded in the

196

colourless test (the colour being conferred by the
embedded material). moderately conspicuous
circular systems, thick and often extensive sheet-
like colonies, and large larvae. Muscles and the
kink in the proximal part of the rectum resemble
Enudiytoma pyrifarme Herdman, L886 (see Hast-
ings 1931). However, colonies of the latler species
have sand grains crowded in the test. consist of
pyriform lohes, and vooids have 4 better defined
posterior stomach.

Eudisioma vitiaium Kot, 1981 contain the same
test inclusions as the present species but is
distinguished by its relatively small upright lobes
with « common basal membrane.

The syntype specimens of Polvcitor discolor
Sluiter, 1909 (ZMA TUT78&5.1-.3) have been
examined and cannot be distinguished from the
present species. Although the symbiotic plant cells
were reported to reach (8mm, none of that size
was found, One of the colonies (7MA TU785.1)
has plant cells to 0.25mi in diameter, and in the
others the cells are 0.1mm to 6.15mm, although
in all specimens there ix a wide range in their
diameter. ‘Thus, they Jall well within the range
recorded for &, alplum, Zooids of P. discolor
also are identical with those of the present species.
Foaids with the low number of stigmata (6 or
7) recorded by Sluiter were not found in the type
material.

Kudistoma unaematum n.sp.
(Fig. 71a)
Disvkreu tos
Tyer Loeatiny: Queensland (Capricorn Group,
Wisturi Reef, rubble fauna, call. P. Kotr 3086,
holotype OM GH46l1; Heron |, revt, north, coll. PK
7-11-45, paratypes OM GH461U0 GH4612 3).
Forxiore Rrearos. Qucenstand (Capricorn Group.
QM G11954 7 GH4613 26; Littou Reel, OM GH4dsn).

Description

Exirenat Aperarance: Colonies form eireu-
lar to jrregular Mat-topped cushions up to 2em
thick and 6em diameter (QM GH4480), usually
fixed by the whole of the lower surface. The upper
surface of the colony is smouth, and openings of
zooids are difficult 10 detect in preserved matenal.
Zooids are arranged in circular systems of up to
5. The outer circle of branchial openings is about
3Jmm in diameter.

In tile, colonies are shades of pinkish-beige, rose,
to olive and brown (Ridgeway [S86: ‘salmon-bulf’,
‘tawny’, ‘ochraceus rufus’, ‘brick-red’, *madder-
brown’, ‘hay’, ‘maroon’, “lawny-olive’, ‘olive'). In
several colonies (QM GH4612 and GH4624) the
colour shades trom brick red al one end to olive
at the other. When preserved the test is Opaque

MEMOIRS OF THE QUEENSLAND MUSEUM

White with a homogenous white suspension in the
surlace. Beneath the surface the test is cloudy-
white and translucent with some minute brown
pigment particles in the surface and around the
zooids, although these disappear with long term
preservation, Some sand is embedded in the basal
part of the colony and in some specimens
penetrates up into the centre, Sand ts absent from
the surface test. Faecal pellets are throughout.
Large and conspicuous patches of pale brown to
dark greenish-brown pigmented cells are in the
base of the colony. The test is soft. In preservative,
vooids are pinkish-beige to beige, with flecks of
brownish pigment on the body wall when Lirst
preserved. The preservative stains a greenish
yellow.

INTERSAL SpRUCTIRE Zooids are robust, about
6mm long when partially relayed but less than
half that length when contracted. Well developed
circular muscles are around each siphon, and the
atrial siphons are long — at least 3 times the length
of the branchial siphons, A narrow band of 3 rows
of branchial tentacles is in the base ol the branchial
siphon. Twelve to 2) longitudinal muscle bands
are on the thorax, and at least 30 transverse ones.
Longitudinal muscles continue in a wide band on
each side of the abdomen. The branchial sac has
about 25 stigmata per raw, and the first row turns
anteriorly along each side of the mid-dorsal line.

The stomach. long duodenal area. posterior
stomach, and weil developed tubules of the gastro-
intestinal gland are in the posterior end of the
abdomen. A hemispherical clump of mature male
follicles is in the gut Joop in specimens collected
in the Capricorn Group in November (QM
GH4619).

Large (up to 0.8mm) embryos project out from
the top of the oviduets of contracted zooids in
colonies collected in October (QM GH46723), and
November (QM GH4619), However, mature
laryae are nol in any of the available colonies.

Remarks: Exdistoma malin usp, has the same
opaque suspension tn the surtace test as the present
species and the testis follicles are in a similar
circular clump. However & malum has a sandy
stalk and mushroom-like colonies while thase of
the present species are flattened and sessile. Other
sessile Species (£. mruscasum nom. nov., £.
pratuiun osp. and &. purpureum asp.) lack the
white suspension in the surface test of preserved
colonies. With the exception of BL purpurenm
map.. the living colonies are readily confused —
the colour range found in the present species
overlaps that at A. pratudum: and & muscosum
nom. nov. Colour (if colonies haye not been too
long in preservative) is helptul in distinguishing

THE AUSTRALIAN ASCIDIACEA 2 197

Fic. 71, Eudistoma anaematum n.sp. (QM GH4619): a, zooid with embryo incubating in brood pouch. Eudistoma
angolanum: b, sand removed from upper surface of colony to show atrial apertures clustered together (QM
GH4663); ¢, thorax showing embryos incubating and sphincter muscles (QM GH4661); d, thorax showing
musculature (QM G11967); e, larva, test vesicles not shown (QM GH4661). Scales: a-d, 0.5mm: e, 0.2mm.

this species from others. Zooids are beige to
pinkish-white in the present species, reddish-
brown in E. muscosum nom. noy., and darkly
pigmented in E. purpureum.

Embryos incubate in the oviduct as in FE.
incubitum n.sp. However they are larger than
those of E. incubitum and are not the same
spherical shape.

Eudistoma angolanum (Michaelsen, 1914)
(Fig. 71b-e)

Polycitor paesslerioides Michaelsen, 1914, var. angola-
nus p. 430.

Polycitor (Eudistoma) angolanus Michaelsen, 1915, p.
452.

Eudistoma angolanum: Hastings, 1931, p. 86. Millar,
1953b, p. 281; 1962, p. 162. Kott 1957a, p. 75.

198

Polvciret anipluss Harimeyver, (919. 9. LOS.
Eudiviomd snakabe Vokioka, 19544, p, 251.

Dis PRION

New Recoros Western Australia (Houlman’s
Abrolhus, WAM 813.83 OM (2/37; Cockburn Sound,
QM GH4662). Queensland (Capricorn Group, OM
11967 GH466l GH4663 4 GH4680; Lizard 1, OM
Gi11966),

Previously Rreonrb, Western Australia (Cape
Boileau Hartmeyer 1919, Hastings [931; Cape
Naturist, Green Pools AM YIQKE AM Y1203 Kotr
947a;). Tokara Is (Tokioku 1954a). West Attica
(Michaclsen [914 (915: Millar 1953b). South Aftica
(Millar 1962).

Descrir ton

Externat Appearance. Colonies are flat-
topped cushions up to lem high and 2em or more
in greatest dimension, The test is densely
impregnated with sand, which also adheres to the
surface of the colony, The sand 1s interrupted only
by zooids. These lie parallel to one another.
perpendicular to the upper surface of the colony.

In life the dark red of the test is seen between
the sand grains. In preservative small dark pigment
cells ure throughout the test, especially around
zouids, and the test is a dirty brown,

Up to 8 zooids are in circles of about 4mm
diameter, although these are hard to see from the
surface, being obscured by sand, Branchial
apertures are around the perimeter of the circle,
and atrial apertures open around the sides of small
circular depressions (rudimentary cloacal cavities)
in the upper surtace, One or 2 atrial openings are
also in the centre of each depression, Branchial
and atrial lobes are conspicuously triangular, and
dorsal lobes of the branchial aperture and anterior
lobes of the atrial aperture (directing the openings
away from one another) project (rom the surface
between the sand grains.

INTFRNAL Srraucrike. In preservative zooids
are pink, with a greenish stomach, They are about
0.5mm long when contracted. The siphons are
both long and each one has a conspicuous bulging
sphincter muscle al the outer end.

On the thorax are 20 to 24 longitudinal muscle
bands and an almost complete cout of about 20
circular bands. Longitudinal muscles continue in
2 wide bands along each side of the abdomen.
Three rows of fairly Jong branchial tentacles and
2 or 3 anterior rows of short stumpy ones are
at the base of the long branchial siphon, A long
pretentacular area occurs in the branchial siphon,
and also a long unperforated prestigmaial area
in the pharynx. About 25 stigmata are in the
anterior row. but these are difficult to count, The
gut has the usual long oesophageal neck, small,

MEMOIRS OF THE QUEENSLAND MUSEUM

smooth stomach, long duodenum, and well-
defined oval posterior stomach, In contracted
specimens the gut is twisted posterior to the
stomach,

One to 3 large embryos ure in the atrial cayily
of specimens collected in the Capricarn Group
during October and November and in January
from Livard I, Tailed larvae are in colonies [rom
Wistan Reef in October (QM GH4661) from
Heron [. in November (QM GH4663) and trom
Lizard [, in January (QM G11966).

The larval trunk is [mm long. and the tail winds
about hallway around it, There are J rows of about
14 long ectodermal ampullae covering the anterior
half of each side of the trunk. They increase in
length with maturity. Larvae have red pigment
in the rather prominent posterior horns of the

trunk haemocoel, in the stalks of the adhesive
organs, and in the ectodermal ampullae. Adhesive

organs in the anterior mid-vertical line ure large
and have a flat-topped axial cylinder in an
ectodermal cup. The larval test is crowded with
vesicles. which originate as terminal expansions
of fine threads that extend through the test from
the ectodermal cells.

Remarks: This species, with its hard sandy
colonies and blackish red pigment showing
between the sand graiis has a characteristic
appearance, as do the zooids, with their long.
sinuous atrial siphons and bulging terminal
siphonal sphincters.

The species appears related to the eastern
Australian £. reginwm, the Indian Ocean species
&£. carnesum osp,, and the Magellame &,
magalhaensis Michaclsen. They all have a similar
larva, with red-brown pigment in the untenor
ampullac and posterior horns of the larval trunk
haemocoel; and they all have well-formed systems
with rudimentary cloacal cavities. Eudistoma
carnesum n.sp. (> Sigillina magalhaensis:
Michaelsen 1930; Kott 1957a) has the same 3 raws
of larval ectodermal ampullae as the present
species, although they are not as long; and its larval
trunk is longer (1.5mm, but only 1.0mm in £
angalanum). Etclistoma angolanum is the only
species of the group that lacks the large test vesicles
and the bare (sand-free) areas over the systems
of zooids. Audixtonia muscosum nom. nov. has
similar accumulations of pigment in the posterior
horns of the larval haemocoel, but is distinguished
by its smooth shiny surface and Jack of cloacal
depressions in the surface.

Michaelsen thought the present species a variety
of Polvetter ( udisioma) paesslerioides. However,
P. paesslerioides yar. typicus has only weak
sphincter muscles. Michaelsen( 1915) subsequently

THE AUSTRALIAN ASCIDIACEA 2

elevated his var. angolanus to full species status
and recognised two varieties, typica and togoensis.
Millar (19536) deseribed a further specimen from
the type location on the African Gold Coast that
has characters intermediate between Michaelsen’s
varieties; and thus it is probable that these
represent no more than intraspecific variations,
The larval trunk of the Gold Coast specimen
(Millar 1953b Fig. 2b) has the same rows of long
papillae on the side of the larval trunk as those
found in the Australian specimens.

Hastings (1931) examined the type of Polyester
amplus: Hartmeyer, 1919 from north-western
Australia. and another large (8cm diameter and
3.5cem thick) specimen fram the same location.
She found the characteristic long siphons and
conspicuous sphincter of E. angolanum in both.

The species has a wide recorded veographic
range from the western African coast to the
western Australian coast, and the records from
the Capricorn Group and Lizard I, suggest the
tropical eastern coast of Australia is included in
the range. There is no known character indicating
that more than a single species is involved. Unlike
the strictly tropical EL carnosum n.sp. which has
been recorded only from the Indian Ocean. records
of the present species do include some from
temperate waters — of both South Africa (Millar
1962) und south-western Australia (see above).
This could be the explanation for the continuity
ol range between the West African coast and the
Indian Ocean.

Eudistoma aureum n.sp.
(Fig, 72)
Fudistonia pyriforme; Kott, 1972a, p. 9.

DistRIBUTION

‘Tyrer Locaciny: South Australia (St Vincent's Gull,
off West Beach Posidonia beds, [2-20m coll, S$,
Shepherd 27.12.66, holotype SAM E20K4) paratypes
SAM E2085).

ForrHer Recorps: None.
Drscrtplion

Exverxat Appearance; Colonies are flat- to
convex-topped lobes, up to 4cm in diameter
narrowing basally where sometimes the test is
produced into root-like extensions. Sand is
embedded in the test throughout the lower part
of the colony, and continues in a layer beneath
the surface of the upper part. Thus, in the upper
half of the colony, sand is absent from the surface
and in the centre. The test is firm and gelatinous
and the embedded sand enhances the firmness of
the colony. Living colonies are reported to be
bright vellow. Zooids are in circular systems.

199

InreRNAL Srreeture: Zooids are large aod
robust, up to lem long even when contracted. In
preservative they are brownish-red, with irregular
patches of pigment scattered in the body wall. The
atrial siphon is about 3 times the Jength of the
branchial siphon. On the thorax are about 15
strong longitudinal muscles. and these appear ta
subdivide. forming more numerous muscles in a
wide band along each side of the abdomen. An
almost continuious coal of circular muscles lies
on the thorax, beneath the longitudinal bands,
There is a wide band of about 6 circles of short
branchial tentacles. Ai least 25 stigmata are in
the anterior row, which curves anteriorly along

Pic. 72, Eudistama aureum n.sp. (holotype SAM E2084):
a. colony: b, scetion of colony showing distribution
of sand jn the tesl: ¢, zo0id, Scales; a,b, lem; e, Imin,

200

the dorsal mid-line. However, the stigmata are
difficult to count in these zooids and the exact
number was not determined.

The oesophageal neck is long and in these
specimens is constricted into 5 more or less equal
segments along its length. Since the whole
abdomen is filled with trophozooite cells and there
are no gonads present, it is probable that these
zooids are entering the vegetative phase. The usual
smooth stomach, long duodenal area, and oval
posterior stomach are in the posterior part of the
abdomen.

Remarks: Kott (1972a), misled by the pyriform
shape of the lobes, assigned these specimens to
Eudistoma pyriforme., However, lobes are much
larger than those of £. pyriforme, and the naked,
sand free test over the upper part of the colony
further distinguishes the species, as does the bright
yellow of the living specimens. Eudistoma
globosum also has a naked sand-free layer of test
over the upper surface, but is distinguished by
the absence of circular systems as well as by its
smaller size, the colour and the absence of a sand-
free area in the centre of the upper part of the
colony. The temperate species, &. macu/osum n.sp.
has a layer of sand in the middle layer of test,
although the sand particles become less crowded
toward the base of the colony. Eudistoma
maculosum is further distinguished from the
present species by its investing colonies and the
2-toned colour pattern of both living and preserved
specimens. The general shape of the colonies, the
firm test, and arrangement of zooids in the present
species, resemble some of the larger specimens of
the tropical E. ma/lum n.sp. (see QM GH798). The
latter species also has sand embedded in the stalk,
but lacks the characteristic layer of embedded sand
beneath the upper surface.

Eudistoma bulbatum n.sp.
(Fig. 73)
Eudistoma pyriforme Kott, 1972d, p. 244.

DistrRiButTion

Type Locauiry:; New South Wales, off Cronulla,
140m, coll. J. MacIntyre 16.6.65 holotype AM Y2204;
paratypes AM Y835 Y842 Y1120. The species is known
only from the type locality.

DESCRIPTION

EXTERNAL APPEARANCE: Colonies are upright
and club-shaped, the lower half swollen, some-
times with some fine basal root-like extensions,
and often divided. They are up to 2.5cm high,
the upper third of the colony about 0.5cm in
diameter, and the lower two thirds about lem in

MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 73, Eudistoma bulbatum n.sp. (paratype AM Y835):
a, colony; b, upper surface of colony showing
openings, atrial apertures directed in toward the
centre; c, zooid. Scales: a, 2mm; b,c, |!mm.

THE AUSTRALIAN ASCIDIACEA 2 201

diameter. The test is sandy throughout. The lower
swollen part of the colony apparently was
embedded in a sandy substrate and has larger
particles of sand adhering to the outside of the
colony than ure embedded in the test.

Zooids aré jn a circle around the narrow upper
part of the colony. The test is raised over the
anterior end ef each zooid. Branchial apertures
are around the outer perimeter. and atrial
apertures around a central depression. One or 2
zooids aré sometimes in the centre of the circle
with their atrial apertures directed out toward the
atrial apertures of the cirele of zooids surrounding
them, Each colony has about 12 zoids.

InrerNar StRucTuURE Zooids are robust and
muscular. On the thorax are about 20 longitudinal
muscles and an almost continuous inner coat of
circular muscles containing at least 40 bands, The
abdomen is almost completely encased by the
longitudinal muscles which continue along cach
side in a very wide band, In these $pecimens the
yooids are about tem long. and are tound
contracted into the base of the colonies.

The branchial aperture is terminal. but is turned
toward the outside of the colony, and its dorsal
lobes are longer than the ventral ones. The atrial
siphon arises {rom the antero-dorsal part of the
thorax and is not longer than the branchial siphon,
The two apertures are well separated by the ventral
inclination ot the branchial siphon and the antero-
dorsal part of the vooid stretched out between
them. Lobes of the apertures are large and
triangular.

An extensive prebranchial region exists behind
the 3 rows of tentacles. About [5 sugmata are
in the anterior row, which curves anteriorly
alongside the mid-dorsal line, although contrac-
tion makes them impossible to count precisely,
The rectum of the contracted zowid is finely
wrinkled and the proximal part of the ascending
limb of the gut is bent up in a Joop posterior
to the stomach, The stomach, duodenal area, and
posterior sLomach are in the posterior end of the
abdomen. The stomach is dark greenish-yellow,
Neither gonads nor embryos are in the available
material.

Remarks: The free-standing club-shaped
colonies of the species are distinctive. A colony
most closely resembles ane of the almost cylio-
drical upright lobes of F. loricariuni (Sluiter. 1909)
which has the same small, simple cireular systems
at zoaids. However A. loricatunr has no sand
around the uppet part of the colony, each lobe
is much smaller, and is attached with others to
a common basal test mass,

Eudistoma carnosum n.sp.
(Fig. 74)

Polyciier | Eudistonia) passierinides: Michraelsen, 1919.
var. hupfen p. 73 (part, malerial from the Seychelles
and Red Sea with cloaeal systems.

Sigillina ( Paessieria) mogalhaensis: Michaelsen. 1930. p
492 (part. mialertal with clouval systems}.

Sigiflina magalhaensis: Kott, }95T7a, p. 79,

Dis) RINE TON

Tyre Locariry Western Australia (Rottnest } Cape
Viamingh, Fish Hook Bay, under undereut of limestone
reels, coll. P, Koth 19,101.51, holotype AM YI289:;
Rotinest |. Geordie Bay, paratype AM ¥1291: Rottnest
L, Mary Cove coll. P, Kott November 1951. paratype
AM Y¥1290).

Nrw Reeorps: Western Australia (Houtmian’s
Abrolhos, WAM 383.75 $14.83 OM GH2/08, Rottnest
1, QM GH4659 GH4660).

Previotsty Rieorurk; Western Australia (Hout-
man’s Abrolhos = Michaelsen 1930; Cockburn Sound

Michaelsen 1930, AM ¥2205 Kort 1957a)-
DescripTion

Exrrvrenat Arerarancr Colonies form robust
sandy, fat-topped cushions, up to 5em long, 4em
wide and 2cm high. Sometimes the surface is
divided by sandy ridges into circular areas, about
2em in diameter with a central, conical prominence
and terminal cloacal aperture. Systems are 3 to
6mm in diameter and contain up to 20 zooids,
Branchial apertures are on the ouler surface of
the colony, and atrial apertures are around the
sides and in the floor of the cloacal cavities that
lic in the centre of each system. Sand is absent
from the surlace test around the cloacal cavity
and usually it does not adhere to the outside of
the colony. Anterior Jobes of the atrial aperture
and dorsal lobes of the branchial aperture are
enlarged and, with their covering of test, project
around the openings. The pointed anterior atrial
lobes are especially conspicuous and form the rim
of the cloacal cavity.

The colour of the living colonies is not known,
Large spherical vesicles 0.3 to 0.5mm in diameter.
are throughout the test, except where the
embedded sand excludes them. [hese vesicles
contain erystalline particles.

InpeRWAD Sreverure: Zooids are large, about
0.5¢m long When contracted. Apertures are on long
siphons with a narrow sphincter musele near the
end of each siphon. The thoracic musculature is
strong with ubout 30 longitudinal bands, and the
cireulay horizontal muscles. form an almost
continuous coal of about 30 bands beneath the
longitudinal ones, The longitudinal muscles
continue along the abdomen in about 2 wide bands
on each side. About 20 moderately long branchial
tentacles aré in 3 rows and some stumpy ones

to
oS
th

MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 74, Eudistama carnosum n.sp.. a, surface view of colony showing branchial openings of a system, With
atnal openings in a rudimentary common cloaca (holotype AM Y1289); b, section through system showing
zooid openings (semidiagrammiatic); ¢, contracted zooid with muscles remoyed from posterior half of abdomen
(holotype AM Y1289); d, larva showing pigment in posterior horn of left haemocoele and pointed extensions
of ectodermal cells around apertures, but test vesicles not shown (WAM 814.83). Scales: a. Imm; c. 0.5mm;

d. 0.2mm.

are little more than papillae in anterior rows, but
these could not be counted. There are about 16
stigmata per row. The dorsal stigmata of the
anterior row on each side curve anteriorly along
each side of the dorsal mid-line.

The abdomen is of the usual form with a long,
narrow oesophageal neck. At the posterior end
of the descending limb of the gut loop is a rather

flabby and inconspicuous posterior stomach.

The rather large (Imm diameter) eggs are dark
red-brown in preseryative. Zooids of a specimen
collected from Houtman’s Abrolhos in August
(WAM 814.83, OM GH2108) have a tailed larva
in the atrial cayity, The trunk is 1.5mm long and
the tail reaches only to its anterior end. A feature
of the larva is the numerous ampullae arranged

THF AUSTRALIAN ASCIDIACEA 2 20)

in 2 rows of about 14 on each side of the median
adhesive organs, The adhesive organs have wide
axial columns and are on short, wide stalks. There
are 3 rows of stigmata. Spikey proceses from the
ectoderm around the apertures extend out into
(he text. Brown pigment ts in the posterior horns
of the larval trunk haemocoel and in the stalks
of the adhesive organs.

Remarks Large cloacal cavities in their
conspicuous sand-free area of test are character-
istic of the species. It is distinguished from F.
reginiwm by its larger colonies and cloacal systems.
longer siphons, large larval trunk with more
Numerous ectodermal ampullae and larger test
vesicles

Michaelsen (1919, 1920) assigned specimens
from the Seychelles and questionably also from
the Red Sea to the western African variety bupferi
ofthe species Palyeiter (Luelistoma) paesslerioides
(Michaelsen 1914). Subsequently (1930), he placed
the Seychelles and Red Sea material with newly
recorded specimens trom Western Australia in
synonymy with the species Polpeitor magulhaensis
Michaelsen, 1907 from the Magellanic region, as
Sigillina (Paessleria) magalhaensis, Sigillina
(Eudistuma) paesslerioides, represented by
varieties hupleri and typicus from West Africa,
was distinguished from &, ( Paessleria) magalhaen-
sty by ity smooth stomach and more numerous
(more than 100) branchial tentacles (Michaclsen
1930), The stomach folds that Michaelsen believed
characteristic of the subgenus Sivi/lina ( Puessleria)
are artefacts and not true stomach folds, and the
division of Eudistoma into the subgenera that
Michaelsen proposed is invalid. Nevertheless the
West African and Indian Ocean specimens appear
s€parate species, their separation valid on
morphological (more numerous branchial tenta-
cles: Michaelsen 1930) as well as geographic
grounds. Only some af Michaelsen's western
Australian and Seyehelles colonies (those with
cloacal systerms) are identical with the newly
recorded material.

The Magellanic species, with similar cloacal
systems and large embedded vesicles (symbiotic
cells?) appear closely related to the Indian Ocean
ones. It ts unlikely they are conspecific because
they have stalked colonies with a rounded head
and much longer zooids, rather than the platformm-
like irregular and sessile colonies of the Australian
specimens for which the present new species is
erected,

Eudistoma carnosum nsp. resembles Ludis-
toma angolanum Michaelsen, 1915, which, like
the present species, was deseribed originally as a
variety Of Polvetior (Eudistoma) paesslerivides

tod

Michaélsen, 1914. Eudistoma angolanum is
distinguished hy its conspicuous band of circular
muscles on each of the siphons (see above),

The spikey ectodermal processes around the
apertures were observed also in Ludlixtonta
valu, and may occur also in other species (see
Annotated Glossary: larvae),

Eudistoma constrictum n.sp,
(Fig. 75. Plate 15b)

Dis rhieu iors

Trpr Locapery: South Australia (Great Australian
Bight, Yorke Peninsula, low water mark under rocks
on headland newr Chinamen’s Hat L.. coll. N. Holmes
6.11.76, holotype SAM P2083. Investigator Group,
Yopgallant 1, bottom ol rock slope near cliffs 7m, coll
N. Holmes 10.4.83, photo index PE0047/ R929, paratype
QM GH2291; Avoid Bay, Golden 1, coll, N. Molmes
9.4.87, paratype OM GH4T86),

Furnire Receorps: South Australia (Great Austral-
jan Bight, OM GH2406; Yorke Peninsula, SAM E2087:
West 1. QM GH2403; Spencer Gull, OM GH4551),

Drserivrion

Exrernat Aprravanet: Colonies are irregular
rounded cushions of maximum dimension dem
and up to lem high. The upper surface slightly
overlaps the base. Zooids open on the upper
surface by separate branchial and atrial apertures
that are placed [airly close to one another in an
oval sund-lree area, Sometimes the test between
zauids is. crowded with sand particles und faecal
pellets, The sand gradually becomes less crowded
toward the base, Sand is nol always present in
the upper half of the colony, although the oval
areas in the surface are quite conspicuous — the
solid layer of test between zooids contrasting with
the thin laver over the top of cach zooid,

Each vooid is contained in a compartment in
the test which is constricted around the wpper part
of the oesophageal neck to form a nurroW canal
between the roomy abdominal and thoracic
cavities. Frequently the contraeted zooids are
severed at this point leaving the thorax behind
in the upper layer of the colony as the abdomen
contracts back into the base, The sand embedded
in the test makes the compartments rigid. Zooids
extend at angles to one another 0 the test. crossing
one another irregularly,

InTrENAL Sreve uke: Zooids are robust and
muscular, They are pinkish-hrown in alcohol
preservative. About 30 longitudinal muscle bands
are on the thorax. More numerous cireular ones
are irregularly distributed and confined to the
middle of the thorax, Longitudinal muscles
continue onto the abdomen in 4 wide hands ov

204

MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 75, Eudistoma constrictum n.sp.: a, section through colony showing zooids opening on the surface in sand-
free areas (paratype QM GH2291); b, zooid openings on surface of colony (holotype SAM E2083); ¢, thorax
showing muscles (paratype QM GH4186); d, whole zooid showing gut loop (paratype QM GH2291); e, larva

(paratype QM GH4186). Scales: a,b, 2mm; c-e, 0.5mm.

each side. Both siphons are relatively short. The
anterior end of the zooid is often flattened, with
both apertures rising from the flat anterior surface.
Short branchial tentacles are arranged in about
7 rows at the base of the branchial siphon. There
are about 25 stigmata per row, but these were
difficult to count. The dorsal end (involving about
5 stigmata) of the anterior row curves forward
along each side of the dorsal mid-line. A short
oval posterior stomach is in the descending limb
of the gut loop.

Up to 4 embryos are present in the peribranchial
cavity of specimens collected in April (QM
GH418). Larvae have a trunk about Imm long
with the tail wound about three quarters of the
way around it, Lateral as well as median ampullae
alternate with the adhesive organs.

Remarks: This species has a smooth, sandy

surface, and sand is present throughout the test
asin E. ovatum and E. sabulosum n.sp. It is readily
distinguished by the oval sand free area of thin
test over the anterior end of each zooid, the
absence of circular systems, and the narrow
constriction of the test between the abdominal and
thoracic test cavities. In Polycitorella spp. there
is a similar constriction, containing a sphincter
which regulates the withdrawal of the zooids from
the surface. However, in E. constrictum a similar
circular muscle is not present in the constricted
part of the test.

The absence of systems is a relatively rare
occurrence in ELudistoma, known only in the
present species, E. microlarvum n.sp. and in the
stalked species E. globosum, E. elongatum and
E. laysani. In most others, zooids are arranged
in rudimentary systems.

THE AUSTRALIAN ASCIDIACEA 2

Eudistoma eboreum n.sp.
(Fig. 76a,b)
DISTRIBUTION
Type Locairty: Queensland (MacGillivray’s Reef
near Lizard I.. 14m, coll. D. Phillips June 1980, holotype
QM GH336).

DESCRIPTION

ExTeRNAL APPEARANCE: The holotype is the
only specimen available. It is a large sessile
cushion, convex on the upper surface, about 3cm
in diameter and Icm thick in the centre. The upper
surface is smooth and rounded. In life it was
reported ‘whitish’. In preservative it is firm, slightly
translucent and pinkish-buff with spherical to oval
brownish-orange pigment cells, about 0.01mm in
diameter, distributed fairly evenly through the test.
Large, black fusiform to branched, dendritic cells
are also in patches, especially around the zooids.
Zooids themselves are whitish in preservative with
some white patches in the body wall.

There are circular systems of 3, 4 or 5 zooids.
Atrial apertures are fairly close together in the
centre of the triangle, rectangle or circle outlined
by the branchial apertures. Branchial apertures
are well separated from one another, and zooids
are not crowded.

INTERNAL STRUCTURE: Zooids are robust, about
Icm long when partially contracted. The atrial
siphon is long and often expands into a balloon-
like structure. A discrete sphincter muscle is
around the distal end of the atrial siphon and
around the short branchial siphon. About 20
longitudinal thoracic muscles overlie an almost
continuous coat of circular muscles and then
extend along the abdomen in a wide band on each
side. About 20 stigmata are in each of the 3 rows,
although the exact number was not determined.
The anterior row, projecting forward along each
side of the mid-dorsal line has more stigmata than
the others.

The oesophageal neck is long. The stomach,
long duodenum and small oval posterior stomach
are at the posterior end of the descending limb
of the gut loop. Gonads in the gut loop at the
posterior end of the abdomen are mature. A large
(l[mm long) embryo is in the atrial cavity.

Remarks: Larvae are not known, but the size
of the embryos present in the atrial cavity of the
holotype indicates the larval trunk would be more
than Imm. The known species with larvae of this
size, gelatinous smooth-surfaced test without
embedded sand, and a sessile habit are EF.
purpureum n.sp. and E. muscosum nom. noy.
Neither of these have the distinctive dendritic cells
of the present species. It is further distinguished

205

by its especially long atrial siphons and sparse
zooids.

Eudistoma elongatum (Herdman, 1886)
(Fig. 76c-f. Plate 15c)
Colella elongata Herdman, 1886, p. 110, Herdman and
Riddell, 1913, p, 882.
Eudistoma elongata: Kott. 1957a, p. 78.

DistTRIBUTION

New Recorps: New South Wales (Jervis Bay, QM
G10037). Queensland (Moreton Bay, QM G4906 G4910
G4966-7 G10047 GI0147 GH356 GH4528-9: Fraser I.,
QM GH4527; Hervey Bay, QM GI1938).

PrevioUsLy Recorpep: New South Wales (Port
Hacking, Port Stephens — AM G12945 G12952 U3937
¥1277 Kott 1957a; Newcastle Bight and Crookhaven
River AM Y12199 Y12200 Herdman and Riddell
1915; Port Jackson Herdman 1886). Queensland
(Currumbin — Kott 1957a; Moreton Bay — AM U3933
Y¥2167 Kott 1957a).

The species is common in muddy habitats and on
wharf piles in protected waters over the whole of its
range.

DESCRIPTION

EXTERNAL APPEARANCE: Colonies consist of
numerous club-shaped to long (up to 60cm)
cylindrical, rope-like zooid-bearing heads about
0.5cm in diameter, on short cylindrical stalks of
almost the same diameter as the head. In life they
are opaque, whitish to iridescent blue. Occasion-
ally they remain more or less the same colour in
preservative, but more often become a brownish-
pink with soft transparent test. Faecal pellets are
in the test, but embedded sand is not.

Zooids are crowded in the head, opening all
around the surface. Atrial and branchial apertures
of each zooid open fairly close together, the atrial
aperture anterior to the branchial opening.
Systems are not formed.

INTERNAL STRUCTURE: Zooids are small, up to
3mm long when contracted. The siphons are
relatively short. About 20 longitudinal muscle
bands are on the thorax forming a rather open
meshwork with a similar number of transverse
bands. Separate longitudinal muscles continue
along each side of the ventral mid-line of the
abdomen, and are not collected into bands.
Stigmata are about 20 per row. Zooids have the
usual long oesophageal neck with the small smooth
stomach near the posterior end of the abdomen.
Gonads are in the posterior end of the gut loop.
A small oval posterior stomach is in the posterior
end of the descending limb of the gut loop.

Up to 8 embryos are in the atrial cavity of
colonies collected in January and April, only 2
in those collected in July and October, and none

206

MEMOIRS OF THE QUEENSLAND MUSEUM

Fig. 76. Eudistoma eboreum n.sp. (holotype QM GH336): a. portion of test showing pigment cells: b. zooid.
Eucdisioma elangatum: ¢,d, colonies (QM G4806 GH4527): e, zovid, contracted, showing embryos packed in
atrial cavity (AM Y1277); f, larva (AM Y1277). Seales: a. 0.5mm; bye, Imm; ¢, 2em, d, lem: f, 0.1mm.

in colonies collected in May. August and
December.

Larvae are small with a trunk 0.5mm long. The
lail reaches only to the anterior end af the trunk.
There is an ocellus and an otolith. Four large
ectodermal ampullae alternate with the stalked
adhesive organs in the median line.

Remarks: The long stalked heads of this species
are unusual in this genus, Specimens are softer
and more flexible than Sigillina australis which
has similar long cylindrical heads. Some degree
of overlap exists between smaller colonies of this
species and some larger ones of Exdistoma laysani,
and the species may be related — F. elongatum
being an indigenous species with its range confined

to protected waters in the northern half of the
New South Wales coast to southern Queensland.
Eudistomea elongatum can be distinguished from
FE, Jaysani by its more numerous thoracie muscle
bands, longer zooids, and more numerous
embryos in the atrial cavity, as well as the much
longer zooid-bearing heads.

Eudistoma gilboviride (Sluiter, 1909)
(Fig. 77. Plate 15d-f)
Polycitor wilhaviridis Sluiter, 1909, p. 6.

DISTRIBUTION

New Recorps, Queensland (Heron 1.. QM G10043
GH4593; Swain Reefs, QM G11961; Lizard L. QM
G11959; Britomart Reef, QM GH4530),

THE AUSTRALIAN ASCIDIACEA 2

207

Fic 77. Eudistoma gilboviride: a, colony (QM GH4530); b, zavid (QM GH4530); ¢, gut loop with branches
of gastro-intestinal gland (QM G11959); d, larva (QM GH4530), Scales: a. Icom; be. 0.5mm: d, 0.1mm,

Previousty Recorned- Indonesia (ZMA TU1269
Sluiter 1909),

Description

External AperArance; Colonies consist of
small (2cm high), crowded, wedge-shaped lobes,
widest on the upper flat surface (up to |.5cm
diameter) and reducing in diameter toward the
base where they are joined to common basal test.
The test is firm and gelatinous and zooids open
into slightly depressed areas on the upper surface,

In life the newly recorded colonics are reported
as green base with dark green lobes mottled cream,
green and yellow, or grey-green. In living colonies
lobes are inflated and appear confluent. Freshly
preserved specimens are greenish-black, with the
pigment in minute cells in the surface test around,
but not in zooids, Beneath the surface layer the
test is greenish grey, and rather transparent with
sparsely scattered dark pigment cells. Zooids are
pinkish-brown to white, Some sand occurs in the
base of the colony and it extends up into the centre

of cach lobe, Long-preserved specimens are grey.
with black pigment cells crowded around and over
zooids resulting in blackish surface marks
emphasing the arrangement of zooids. In the type
specimen (ZMA TUI269) the colour pattern
shown by Sluiter (1909) is still recognisable.
demonstrating the unusual stability of pigments
in this species. The type differs from the newly
recorded material in having yellow pigment im the
raised swellings of solid test between the depres-
sions and furrows into which zooids open.
Depressions are made conspicuous by the
concentration of dark pigment always found
associated with zooids in this species.

Zooids all open on the flat upper surface of
each lobe. In small diameter lobes they are in a
circle just inside the outer margin of the upper
surface. As the lobes increase in diameter 2 or
3 zooids form small systems with their atrial
apertures close together, and sometimes a few
zooids seem not part of a circular arrangement.

208

INTERNAL Structure; The zooids are about
4mm long when contracted. and not particularly
muscular. The atrial siphon is longer than the
branchial siphon. Muscle bands are fine, about
14 longitudinal crossing about 20 circular bands
on the thorax to form a rather open mesh,
Longitudinal muscles extend along the ventral side
of the abdomen, one band each side of the mid-
ventral line. When contracted they draw up the
ventral part of the abdomen causing the proximal
part of the rectum to curve out, Sometimes the
whole posterior end of the gut is bent up against
the rest of the abdomen.

Stigmata are reduced in length toward the
ventral end of each row. The anterior row has
24 stigmata, the dorsal 4 turning anteriorly along
the mid-dorsal line, the middle row 20 and the
posterior row [8. There are 3 rows of branchial
tentacles. The large, oval, posterior stomach is in
the posterior end of the gut loop. The gastro-
intestinal gland has long tubules curving around
the rectum.

Testis follicles are not crowded. One or 2
embryos are in the atrial cavity of specimens taken
from Lizard 1. in November. In the colony from
Britomart Reef (QM GH4530) are 2 embryos, one
immature and the other a tailed larva. The larval
trunk is large (0.9mm long), and the tail curves
up across the left side of the anterior end of the
trunk and over the upper surface. The paired,
lateral, ectodermal ampullae are large and leaf-
shaped extending anteriorly and terminating in
a point, They are dorsal and ventral to the adhesive
organs, and alternate with them. The ventral pair
have an unusual rounded prominence at the
posterior end.

Remarks: Small, flat-topped and wedge-
shaped lobes of the colonies and dark pigment
cells that persist in the surface test after preser-
vation are distinctive, as is the rather sparse
distribution of zooids, the small systems, and leaf-
shaped ampullae of the larvae. In E. glaucum
numerous lobes arise from common basal test but
they are a different colour and are larger and more
rounded. They cannot be confused with colonies
of the present species.

Eudistoma glaucum (Sluiter, 1909)
(Fig. 78)

Polycitor glaucus Sluiter, 1909, p. 12.

Eudistoma glaucus: Tokioka and Nishikawa, 1975, p.
331.

Eudistoma rigida Tokioka, 1955b, p. 50. Not Kott, 1981,
p, 152 (< E. tigrum nsp.); Eudistoma rigidum
Monniot and Monniot, 1987, p. 70 (2? < E. muscosum
nom, noy.).

MEMOIRS OF THE QUEENSLAND MUSEUM

2? Eudisioma olivaceum: Monniot and Monniot, 1987,
p. 67. Not Van Name 1902, p. 120.

DistTRIBUTION

New Recorps: Queensland (Capricorn Group, QM
G11952 G11962-5 GI1979 GH3005 GH4119 GH4426-
31 GH4441 GH4452 GH4468; Swain Reefs, QM
GH4469; Broadhurst Reef, QM GH4425; Little Mary
Reef, GH279).

Previousty Recorben: Palau Is (Tokioka 1955b).
Indonesia (Sluiter 1909). Okinawa (Tokioka and
Nishikawa 1975), Fiji (Kott 1981).

DESCRIPTION

ExternAt. APPEARANCE: Colonies consist of
large (up to 3cm diameter) rounded or cushion-
like heads, usually with a short thick, basal stalk.
Often several heads of various sizes arise from
a common basal mass. The surface of the colony
is smooth and shiny. The test is gelatinous and
firm. Living specimens are a vivid, deep, moss-
green becoming blackish-blue in preservative. The
pigment leaches into the preservative and although
some minute dark pigment cells persist, they
disappear in time from the colony. Sometimes
zooids are green when first preserved, with the
pigment especially retained in the gut, gonads and
body wall. In due course pigment is lost altogether
from preserved zooids. The test contains some
sand, especially in the stalk and in the centre of
the colony but usually it is absent from the softer
test of the heads of the colony. Faecal pellets are
also present in the test and often are coloured
green. Zooids are arranged in small circular
systems of 4 or 5 zooids with their atrial apertures
in the centre of the circle.

INTERNAL Structure: Zooids are robust and
long, even contracted ones being up to lcm long.
However, in comparison with zooids of some other
species (eg. E. anaematum n.sp., E. purpureum
n.sp. and £. pratulum n.sp.) both the thorax and
the atrial siphon are relatively short. About 20
fine longitudinal muscle bands are on the thorax,
and these extend along each side of the abdomen.
More numerous (about 50) inner circular bands
are evenly spaced on the thorax and around the
branchial and atrial siphons. Twenty long
rectangular stigmata are in the posterior row and
25 in the anterior row, which has its dorsal end
curving forward along each side of the mid-line.
Extensive pre- and post-stigmatal regions are in
the pharynx. The oesophageal neck is long and
thin. Gonads are in the gut loop and testis follicles
spill out over its sides. There is a rather indistinct
posterior stomach. A delicate but relatively long
vascular appendix projects from the posterior end
of the zooid.

In the newly recorded material embryos (one

THE AUSTRALIAN ASCIDIACEA 2

209

Fie, 78, Eudistoma glaucunt: a, colony (QM G11962): bed. outlines of various colonies (QM G11952 GI1962
G11979); e, zooid (QM G11979); f, larva (QM G11979). Scales: a. 2mm; b-d. Icm; e, 0.5mm: f, 0.2mm.

or 2) are in the atrial cavity of colonies taken
from the Capricorn Group in December and
January (QM G11963 G11979), but not in those
collected in March, July or September. The larval
trunk is about |,2mm long.

The adhesive organs are in a median vertical
row anteriorly. They have short thick stalks and
vertically elongated axial platforms of columnar
cells in shallow epidermal cups. The adhesive
organs alternate with epidermal ampullae in the
mid-line, and 3 lateral accessory ampullae are on
each side, one more or less on each side of the
base of each adhesive organ.

Remarks:: Tokioka and Nishikawa (1975)

concluded that Eudistoma rigida Tokioka, 1955b
from the Palau Is, with its green test, but yellowish-
brown rather than green zooids, was distinct from
the present species. However, zooids and colony
of both species resemble one another, and in
preservative become the same bluish-black. They
are here considered synonymous. Eudistoma
marianense Tokioka, 1967a has a similar colony
and larva, although the larval trunk is slightly
longer than that of the present species. The colour
of the Marianas Is specimen is not recorded. The
present species is never the red-brown colour of
the small colonies assigned to &. rigidum by
Monniot and Monniot (1987),

210

Ludisiona viride Tokioka, 1955b, from the
Palau Is hus its green pigmentation principally
in the zoids, and they can be seen through the
translucent test, while Lhe whole test is green and
opaque in the present species, Ludistoma viride
also has relatively large zooids and an incubatory
pouch. It appears to be a synonym ol Sigillina
signifera (see above). Tokioka and Nishikawa
(1975) have discussed the relationship of £.
tokarae Tokioka, 1954a from the Tokara Is, with
the present species. Their view that the former
species represents juveniles of E, glaucum seems
unlikely since #&. tekarae bas a milky white
translucent test, while the principal characteristic
ol the present species is its Opaque test, green when
living and blackish blue in preservative.

lhe colour of the colony and the distribution
of pigment in E glaucum resembles that in &.
elivaceum (Van Name, 1902) from the tropical
Athintic. Specimens of the latter species from the
Bahamas have a variety of colony forms. some
with sessile heads on a basal mat and some long
und stalked (AMNH349: see also Van Name 1945).
Although some resemble the shape of colonies of
the present species, heads are smaller with fewer
wooids and stalks are longer, Further, it is unlikely
that the tropical Atlantic species has a range that
includes the western Pacific, Therefore, the two
should not be regarded us conspecific. Monniol
and Monniot (1987) refer to a specimen (undes-
cribed) of & wlivacenm from Fiji, but it probably
belongs to the present species,

The posterior abdominal vascular stolon of this
species is longer than in most others of the genus.
It extends down into the stalk as in Sigillina spp.,
but lacks the extension of the epicardium which
occurs in the latter genus. Audisioma superlatum
n.sp. has a similar yaseular stalon

cudistoma glabosum Koll. [457
(Fig. 79a-d)
Audistonia wlobosum Katt, 19574 P- 72

Dis pa sul pans

New Reeokos: Western Australia (Houtman's
Ahralhos, WAM 832.83 £39.83; Rottnest 1, QM
GH4563, WAM 133.75; Marauret River, WAM 815,83
OM GH2/28) Queensland (Cupricorn Group, QM
GH4579),

Previousey Reconpes Western Australia (Rottnest
}. AM YI212 Y1270 4 Kott 19574).

DESORTFTION

EXteRNAL APPEARANCE, Colonies usually
consist of rounded Lo oval or conical heads that
overlap ashurt, thick stalk. Stalked heads are up
to 4om high, Several heads sometimes arise from

MEMOIRS OF THE QUEENSLAND MUSEUM

hasal test. ur the stalk may branch. The surface
test af the head of the colony is always free ol
sand. However, sand grains are crowded in the
test and project up from the stalk into the centre
of the head of the colony, Faecal pellets are
throughout the colony.

In life the colour of the sand crowded in the
stalk affects its colour. The gelatinous test of the
head is darkly pigmented, the colour becoming
progressively more intense toward the top of the

colony. Around the lower half of the head, the
embedded sandy core projecting up from the stalk

is closer to the surface and the colour less intense.
The colour on the top of the heads is *blackish-
slate’ (Ridgeway /886). Kott (1957a) recorded
specimens from Rottnest tl. as blackish-green,

In treshly preserved material are both black and
tan spherical pigments cells up to 0.04mm in
diameter in a layer beneath the surface of the
colony, and in the thoracic body wall of zooids,
Zooids are otherwise whitish-yellow with a
greenish-yellow stomach. In long-preserved
colonies /rom Western Australia the tan colour
persists, but not the black.

INTERNAL Srepecrurn: Zoos are relatively
long and slender when relaxed, extending from
the surlace of the head down into the base of
the stalk. However, they contract Lo shout 2.5mm,
The atrial siphon is longer than the branchial
siphon, and is located well down the thorax. There
are 3 rows of branchial tentacles. About 15
longitudinal thoracic muscles continue in a wide
band along each side of the ventral line of the
abdomen, causing it to curl up When contracted.
An unperlforated prestizmatal area is. in the
anterior part of the pharynx. The stigmata,
perhaps 15 to 20 per row, are difficult to count
The gut and gonads are in the usual position in
the posterior end of the abdomen.

A single large embryo is in the atrial cavity of
specimens taken from Rottnest |, in March, and
Margaret River in January. The larval trunk is
{.7Jmm long. It is the largest Known for an
Ludistoma species. The tails winds almost three
quarters of the way around the trunk. Wide, rather
Nut median ampullae alternate with the Jarge
adhesive organs in the vertical mid-line anteriorly.

Remarks: Superticially colonies from Western
Australia with their crowded zooids in stalked
heads resemble those of F. elongarum, except they
are a darker colour, do not become long and
cylindrical, have sand embedded in the stalk and
the centre of the head, and have large spherical
pigment cells, The pigment cells resemble some
found in &. maculosum n,sp, and F, rigrum n.sp.
but are larger. Evdistoma museosum gom, noy.

THE AUSTRALIAN ASCIDIACEA 2

211

Fic. 79, Eudistoma globosum: a, colony (QM GH4563); b, section through colony showing sand (WAM 815.83);
¢, thorax showing brown pigment in body wall (QM G4579); d, larva (QM GH2128). Eudistoma gracilum
n.sp.: e, zooid (holotype QM GH4531); f, larva (QM GH4533), Scales: a,b, lem; eye. 0.5mm: d, 0.2mm; fF,

0.1mm.

has shiny brownish red pigment cells of a similar
size in freshly preserved material but they
disappear in preservative, and are never black as
in the present species. The species are further
distinguished by the shape of the colonies and the
arrangement of the zooids.

Eudistoma gracilum n.sp.
(Fig. 79e,f)
DisTRipution
Type Locauiry:; Queensland, Heron |. north reef. coll.
P. Kott 15.1.83, holotype QM GH4531; paratype QM
GH4532.

FurtHer Recorps: Queensland (Heron L., QM
GH4533 GH4837).

DESCRIPTION

EXTERNAL APPEARANCE: Colonies form
smooth-surfaced sheets, up to 6¢m in maximum
diameter and only about 0.5cm thick. In life, the
test is a soft, red or ‘orpiment orange’ (Ridgeway
1886) translucent jelly resembling a water-ice.
Zooids, white or orange, are easily seen through
it. Some faecal pellets are in the test. In
preservative colonies are a rather dirty, transpar-
ent, beige and zooids are green, the green being

212

especially concentrated in the muscles. The soft,
sometimes almost mucus-like test fills concavities
in the surface of the coralline rubble over which
it grows and zooids often are drawn down into
these concayities. The substrate thus forms a
framework for support and protection of these
delicate colonies.

Systems were not identified in the soft test,
although it is possible they were present in the
living colony, as the atrial siphons are relatively
long and probably open in the centre of a circular
system. Spherical brown cells, about 0.01mm
diameter, are scattered evenly in the test and
sometimes these collect together in almost
spherical reservoirs in the test.

INTERNAL Structure: The delicate, relatively
small, slightly contracted zooids are only about
2mm long. The 12 longitudinal muscle bands on
the thorax, continue along the abdomen in two
wide bands. No circular muscles were detected on
the thorax. There are only about 10 stigmata per
row. The oesophageal neck is long and narrow.
The small, smooth stomach and small oval
posterior stomach are in the posterior end of the
abdomen.

A single embryo is in the atrial cavity of
specimens collected in May (QM GH4533). The
larval trunk is 0.6mm long and single ectodermal
ampullae alternate with the adhesive organs in the
anterior mid-line. The tail winds almost three
quarters of the way around the trunk.

RemMArKs: The species is distinguished by its
small zooids with relatively few stigmata, fine and
exclusively longitudinal musculature, and the soft
test and thin colonies. The larval trunk is about
the same length as that of &. incwbitum n.sp., but
is not so deep and its ampullae are not so wide.
The larvae of E. laysani and E. elongatum also
are similar, but smaller.

Eudistoma incubitum n.sp.
(Fig. 80)

DISTRIBUTION

Tyre Locatrry; Queensland (Capricorn Group, NW
Wistari Reef, rubble fauna, L.WM_, coll. P. Kott 11.11.85,
holotype QM GH4537, paratypes QM GH4538).

Furtuer Recorps, Queensland (Capricorn Group.
QM G11953 GH2268 GH4534-6 GH4565 6 GH4584).
DESCRIPTION

EXTERNAL APPEARANCE: Colonies consist of
upright, cylindrical to mushroom-like lobes up to
2cm high. In young colonies (QM GH2268) zooids
open on the upper free end of the lobe, and the
anterior part of each zooid projects from the
surface. Larger lobes have circular to oval heads
up to 2cm in diameter, supported by firm

MEMOIRS OF THE QUEENSLAND MUSEUM

cylindrical basal stalks. Sometimes the stalks
branch, and numbers of lobes arise from common
basal test. Living colonies are white, with
transparent test and white zooids, and are the same
in preservative. Faecal pellets are in the test,
especially in the stalk, but sand is not. Circular
systems of 4 or 5 zooids are seen through the
transparent test of the head.

The surface test contains evenly spaced,
conspicuous spherical cells about 0.05mm_ in
diameter and about 0.3mm apart. These give the
colony a speckled appearance when magnified.

INTERNAL STRUCTURE: Zooids are small, about
3mm when strongly contracted. When relaxed they
occupy the whole height of the colony and are
slender. About 10 longitudinal muscles are on the
thorax, continuing along the whole length of the
abdomen in up to 7 bands of unequal width on
each side, although sometimes only a single wide
band is on each side of the ventral mid-line.
Contraction of the longitudinal muscles not only
makes the oesophagus minutely wrinkled, and the
rectum folded and bent, but also bends the
abdomen up against the ventral border of the
thorax. A band of about 12 circular muscles is
around the middle of the thorax. About 10
stigmata are in the anterior row, but they could
not be accurately counted in these contracted
specimens.

The gut is characteristic of the genus with a
small smooth stomach, long duodenal region and
oval posterior stomach. Long tubules of the
gastro-intestinal gland lie along the proximal part
of the rectum. Gonads are in the distal part of
the gut loop. The male follicles are relatively large
when mature. The proximal part of the vas
deferens expands into a long spindle-shaped
seminal vesicle when filled with sperm.

In specimens collected in May, July, August
and November (QM GH4538 GH4584 GH4565
GH4537 respectively) a row of up to 4 embryos
is in the distal part of the oviduct, just posterior
to the thorax. Embryos lie in a developmental
sequence with the most advanced at the top. They
are incubating in the oviduct, and consequently
were fertilised there, rather than in the atrial cavity.

Larvae are almost spherical, the trunk about
0.6mm long. The tail is moderately long, reaching
about three-quarters of the way around the trunk.
The surface of the larval test has the same speckled
appearance as the surface test of the adult colony.
This is due to terminal expansions of thread-like
extensions from the larval ectoderm. These vesicles
can be removed with the larval test. They resemble
similar structures in the angolanum group of
Eudistoma (see above: Eudistoma; and larvae in

THE AUSTRALIAN ASCIDIACEA 2

Fic, 80, Eucistoma incubitum: a, colony showing systems of zooids (holotype QM GH4537): b, colony showing
speckled test (QM GH2268); ¢, zooid showing body organs (QM GH4584); dye zooids showing incubating
embryos (holotype GH4537); f, larva (QM GH4584). Scales; a, 5mm; b, 2mm; e-e, 0.5mm, f, 0.2mm.

the Annotated Glossary). Paired lateral ectoder-
mal ampullae alternate with the adhesive organs
which are almost sessile, on short, wide
stalks.

Remarks: The speckled appearance of both
larval and adult test in this species is unique. The
presence of developing embryos in the top of the
oviduct is also unusual, for in other species
examined in the course of this study maturing

embryos are in the atrial cavily where fertilisation
probably occurs. The spherical shape of the larval
trunk is also distinctive. The white transparent,
lobed colonies and small zooids sometimes
projecting from the upper surface of each lobe
resemble small lobes of E. /aysani. However, in
the latter species the living colonies are an
iridescent blue and the larvae are smaller with a
relatively long, narrow trunk.

214

Eudistoma laysani (Sluiter, 1900)
(Fig. 81)
Distoma laysani Sluiter 1900, p. 9.
Polycitor laysani: Sluiter 1909, p. 4.
Eudistoma laysani: Millar 1975, p. 221. Not Tokioka
1967a, p. 119: 1967b, p. 394.

Distoma parva Sl\uiter, 1900, p. 6.
Eudistoma parvum: Kott 1957a, p. 77
? Polycitor regularis Sluiter 1909, p.
Polycitor ( Eudistoma) olivaceum: Tokioka, 1942, p. 497.
” Eudistoma album F. Monniot, 1988, p. 210.

DistRIBUTION

New Recorps: New South Wales (Botany Bay,
AM2206), Queensland (Currumbin, QM GH4539;
Burleigh Heads, QM G9268 GH4541; Caloundra, QM
GH4546; Mooloolabah, QM GH4545; Noosa, QM
GH4543 GH4547; Tannum Sands, QM GH1499; Heron
L., QM G10039 GI1953 GH2267-8 GH4548-9; Sarina,
QM GH4544), Lord Howe I. (QM GH4542),

Previousty Recorpep: New South Wales (Lake
Macquarie — Kott 1957a). Palau Is (Tokioka 1942).
Indonesia (Sluiter 1909, Millar 1975). Phillipines (Millar
1975). Hawaii (Laysan Sluiter 1900).

This is a common and conspicuous species in the
western Pacific, and is found higher up the intertidal
region than any other aplousobranch ascidian. The
majority of the records are from the intertidal region,
sometimes even at mid-tide level. Only the record from
the Phillipines (Millar 1975) is from a greater depth
(22m).

DESCRIPTION

EXTERNAL APPEARANCE: Colonies consist of a
basal mass of common test supporting numerous
lobes. Each lobe consists of a cylindrical,
sometimes branched stalk, and a slightly expanded
head, its upper surface flat, rounded, or conical.
Lobes are about 3mm to Icm high. Stalks are
firmer than heads, which have delicate transparent
test. Abdomina of the zooids are crowded, parallel
to one another down the length of the stalk and
into the basal test. In addition to the abdominal
portions of the zooids, the stalks contain faecal
pellets, and both confer their colour to the stalk
and make it quite opaque. Epizooites and other
foreign particles are often on the stalk and basal
test but never any embedded sand.

Atrial apertures are always anterior to, or more
central than the branchial apertures, but there are
no systems. In small, juvenile lobes with up to
6 zooids the anterior ends of the zooids project
separately above the surface of the head, but in
larger colonies only the apertures protrude. Larger
lobes with rounded, club-shaped or pointed heads
contain up to 100 zooids opening all over the
surface of the head. In many specimens the size
of the lobes from one basal mass is varied, and
small, presumably developing lobes, such as those

MEMOIRS OF THE QUEENSLAND MUSEUM

described by various authors for E. /aysani, are
present.

The separate lobes of living colonies when
inflated appear confluent with one another. They
are white with ‘pale antwerp blue’ (Ridgeway 1886)
iridescence. In preservative the blue pigment only
occasionally persists and the colonies are pink or
white.

INTERNAL StRucTURE: Extended zooids are
often particularly long, with a long, narrow
oesophageal neck. However, the thoraces are
seldom more than Imm. Contracted zooids are
no more than 2mm long. Zooids are narrow and
much less robust than most other species of this
genus. Both branchial and atrial lobes are large
and triangular, and a distinct circular muscle
surrounds each relatively short siphon, From 8
to 16 fine longitudinal muscles are on the thorax.
These extend along each side of the abdomen as
separate fine muscles rather than wide bands.
Circular muscles, beneath the longitudinal bands,
are also fine and are confined to the middle of
the thorax. There are 16 long tentacles in a
posterior row and further tentacles in 3 additional
anterior rows. The atrial siphon originates
opposite the first row of stigmata, well down the
dorsal surface. A long prestigmatal region is in
the anterior part of the pharynx.

The stigmata can be more easily counted in this
than in other species of this genus, possibly because
of the relatively fine musculature. Only 12 stigmata
are in the posterior row, but up to 20 are in the
anterior row. The dorsal 3 stigmata in the anterior
row curve up along the mid-line, toward the dorsal
ganglion. The usual small, smooth-walled stomach
is at the posterior end of the abdomen. There is
an oval posterior stomach but it is not always
distinct. Tubules of the gastro-intestinal gland
extend anteriorly along the ascending limb of the
gut loop.

Mature gonads and up to 8 embryos are in the
atrial cavity of specimens from Heron I. collected
in February (QM GH4550). Specimens from
Batehayen collected in April (MV F53397), from
Botany Bay collected in May (QM GH4540), and
from Caloundra (QM GH4546) and Noosa Heads
(QM GH4543) collected in November, have a
similar number of embryos in the atrial cavity.

Larvae are small, the trunk only 0.4 to 0.5mm
long. The tail is wound halfway around it. There
is an otolith and an ocellus, and 4 single median
ectodermal ampullae alternate with the stalked
adhesive organs.

Remarks: The multilobed colonies, with
delicate transparent test on the terminal part of
the lobes, and without embedded sand; small

THE AUSTRALIAN ASCIDIACEA 2 215

if
AANA
at

Onna
mi

Fic. 81, Eudistoma laysani: a, large colony (QM GH4541); b-d, smaller colonies (QM GH1499 GH4548 AM
Y2206); e, zooid, with 4mm of oesophageal neck excised (AM Y2206): f, thorax with incubating embryos
(AM Y2206); g, larva (QM G9268). Scales: a, 2mm; b-e, 1mm; f, 0.5mm; g, 0.1mm.

216

zooids with fine muscles; and small larvae are all
characteristic of the species, as is their whitish-
blue iridescence. Their colour resembles that of
Ritterella prolifera (Oka, 1933), but in the latter
species the lobes are sessile rather than stalked
(see Kott 1972d).

A wide range exists in the shape and size of
the lobes of these colonies, occasionally within
the one colony (QM GH4540 GH4550). More
often the stalked lobes are a uniform size in each
colony. Variations in their diameter are probably
the result of growth. However, smaller lobes occur
more frequently in the tropics than in temperate
waters, and there may be a cline in the populations,
The colonies resemble lobes of E. elongatum in
the absence of systems, blue iridesence and small
larvae, and it is possible that the latter species
is conspecific, representing populations with long,
rope-like heads at one end of a cline.

The type material of Eudistoma laysani (Sluiter,
1900) from Laysan has small lobes, each with a
single circle of zooids with their anterior ends
projecting from the free end of the lobes. Millar
(1975) recorded similar specimens from the
Philippines and Indonesia. Millar’s specimens
contained small larvae similar to those in the newly
recorded material. The zooids in the lobes of the
Australian material usually are more numerous,
crowded and not arranged in circles, but single
circles do occur in the smaller lobes. Thus, until
some character is identified to indicate different
species, the specimens referred to in the synonymy
and distribution (above) are regarded as
conspecific.

Tokioka’s (1967a,b) specimens from the Palau
Is and from Vietnam, respectively, with long,
rather irregular colony lobes and relatively large
larvae are not of this species. The colonies from
Vietnam (Tokioka 1967b) resemble those of
Eudistoma toealensis Millar, 1975, and the larvae
also are similar. Larvae of the Palau Is specimen
(Tokioka 1967a) suggest it is yet another species.

Eudistoma segmentatum (Sluiter, 1909) has a
similar colony but a larger zooid than E£. /apsani.
Eudistoma parvum (Sluiter, 1900) recorded from
Laysan, and a possible synonym from Japan EF.
parvum Oka, 1927d (see also Tokioka 1953,
1954b), is another similar species, although the
Japanese colonies are solitary stalked heads rather
than the multi-lobed ones of the present
species.

Zooids (but not the colonies) of the present
species resemble those of Eudistoma gracilum
n.sp. in their small size and fine muscle bands.
The colonies of the latter species are flat sheets
rather than separate stalked lobes joined to a basal

MEMOIRS OF THE QUEENSLAND MUSEUM

test mass or stolon, and the test is extremely soft
and mucus-like.

Eudistoma maculosum n.sp.
(Fig. 82. Plate 16a-d)
Eudistoma renieri: Kott, 1957a, p. 74; 1972a, p. 10,
1972b, p. 171.
Eudistoma pyriforme: Kott 1972a, p, 9; 1976, p. 58 (part,
specimen from Mallacoota Inlet).

DisTRIBUTION

Tyrer Locatiry: South Australia (Ward L., 20-25m,
coll. N, Holmes and S. Shepherd 31.3.82, holotype QM
GH1304; Topgallant 1., 5m, coll. N. Holmes and 8.
Shepherd 29.3.82, paratypes QM GH1278; Flinders 1.,
Investigator Group, 8m in caves, coll, N. Holmes 10.4,83,
photo index PE 0024 R965/R967, paratypes QM
GH2391),

FurtHer Recorps; Western Australia (Pt. Peron,
AM Y1299 Kott 1957a). South Australia (Great
Australian Bight — Kott 1972a,b; Ward 1, QM
GH1282). Victoria (Mallacoota Inlet — MV F5482 Kott
1976). New South Wales (Jervis Bay, QM GH4605).

DESCRIPTION

Colonies form firm, fleshy, flat-topped oval
cushions to extensive fleshy sheets 0,5 to 1.S5cm
thick, with rounded borders. They are fixed by
the whole or part of the basal test. The surface
is smooth. Zooids are in circular systems of 6 to
8. Living colonies are white with black zooids.
In preservative all colonies are opaque, slate-grey
to black with blackish to blue zooids and brown
to tan pigment cells concentrated in patches near
the surface of the otherwise whitish, cloudy,
translucent test. These brown to tan pigment cells
form an inconspicuous, mottled, rusty-looking
pattern on the surface of the colony. South
Australian specimens are white with black zooids,
and the specimen from NSW is brown and white.

Sand is embedded in the middle layer of test
and becomes less crowded toward the base. Sand
is usually absent from the upper half of the colony.

INTERNAL STRUCTURE: Zooids are robust with
about 20 longitudinal muscles on the thorax that
continue onto the abdomen in a wide band on
each side of the mid-ventral line when contracted.
In relaxed zooids the longitudinal muscle bands
are separate from one another. There is an almost
continuous coat of circular thoracic muscles.
Circular muscles are on the siphons, but they do
not form a distinct sphincter. About 20 long
stigmata are in each row. The gut has the divisions
characteristic of Eudistoma.

A single large embryo projects from the atrial
cavity in colonies collected from Point Peron
(WA) in January (AM Y1299), from South
Australia in November (see Kott 1972a) and from

THE AUSTRALIAN ASCIDIACEA 2

won and
SS

S

AS

Wet
LAST
SS

Fic. 82, Eudistoma maculosum n.sp.: a, thorax showing
muscles (holotype QM GH_1304); b, abdomen showing
gut loop and longitudinal muscles (holotype QM
GH1304); ¢, zooid showing lower third of abdomen
contracted up against middle third (QM GH4605);
d, larva (AM Y1299). Scales: a-c, 0.5mm; d, 0.2mm.

Jervis Bay in August (QM GH4605). The larval
trunk is 0.9mm long and the tail is wound almost
three-quarters of the way around it. Larvae are
unusual in having 3 large adhesive organs each
with a short stalk and large, vertically elongated,
oval platform of columnar cells in a shallow
epidermal saucer. Bract-like epidermal ampullae
are in the mid-line, one dorsal and one ventral
to the base of each of the adhesive organs. Larvae
have 3 rows of stigmata.

Remarks: This commonly encountered, robust
temperate species resembles, and may be related
to, the tropical species Eudistoma tigrum n.sp.

217

Both have the same pattern of surface pigmen-
tation which, in preserved material appears as rust-
like patches. They also form extensive rather sheet-
like colonies with rounded borders, and have their
zooids in circular systems. The principle distinc-
tions between them are in the larvae — the present
species having a larger larva with bract-like
ectodermal ampullae and vertically elongated
platforms of adhesive cells in the short, thick-
stalked adhesive organs, while those of F. tigrum
n.sp. are smaller, have adhesive organs with long
narrow stalks alternating with median paired
ampullae. Where larvae are not available, the
temperate — as opposed to tropical — range of
the present species must be relied on to separate
it from &. tigrum n.sp. Larvae with the same
elongate adhesive organs are known for E.
glaucum, E. purpureum n.sp. and E. marianense
Tokioka, 1967a, but the larval trunk in these
species is much longer (1.2mm, 1.5mm and |.5mm
respectively), and their colonies are mushroom-
like with short thick stalks (EL glaucum and E.
marianense), or large rounded, sessile cushions (E.
purpureum), rather than the extensive sheets of
the present species. Eudistoma muscosum nom.
nov. has larvae of similar length and the same
elongate adhesive organs as the present species.
The test is also darkly pigmented with tan and
dark coloured pigment cells. However, the two-
toned colour pattern of E. maculosum is not
present, and the colonies do not form the same
extensive sheets.

In one specimen (Kott 1972a, Wright I.) the
second and third adhesive organs are joined, and
there is one long protruding ridge of columnar
cells,

Eudistoma malum n.sp.
(Fig. 83a,b)

Disrrisu TION

Type Locattry: Queensland (Capricorn Group,
Heron L., side of bommie 10m, coll. N. Coleman 20.7.73,
AMPL 87, holotype QM G11939; Heron I., 8-10m, coll.
P. Kott March 1975, paratype QM G11940).

FURTHER Recorps: Queensland (Capricorn Group,
QM GH4635-9 ?GH4851; off Gordonvale, QM GH798).

DESCRIPTION

ExTerRNAL APPEARANCE: Smaller colonies
consist of top- to mushroom-shaped lobes, often
with an almost completely spherical head, about
2 to 3cm diameter, on a short, thick stalk. The
largest colony available (QM GH798) is an upright
cone 4cm high and 3cm diameter. Sand is in
varying concentrations in the stalk and sometimes
extends up into the centre of the head. Zooids
open all around the head, and are in circular

218

systems of 3 urd zovids, In lile the holotype colony
was reported @ ‘yellow ball ascidian’, However,
the paratype and other colonies are shades of
purple ‘burnt sienna” at the top of the stalk
to ‘madder brown’ on top; ‘cinnamon rufus’
shading to a transparent stalk (Ridgeway 1886);
and maroon purple with a sandy stalk, In
preservative colonies become translucent and
greyish white with some minute (0,01mm) blutsh-
black to brown pigment cells in the surface layer,
and [airly evenly distributed through the
remainder of the test, These cells are also found
lying free in the space between the zooid and the
lest. Olten a white suspension is in the surface
test. Usually pools of greenish-brown to brown
pigment cells ure at the base of the stalk, Sand
embedded in the stalk affects its colour. In
preservative 2ouids ure cream Lo pink.

Inires ar Steuerure: Zooids are robust but
relatively short, about 3mm Jong when contracted.
‘The atrial siphon usually is 2) lo 3 times the length
of the branchial siphon About 15 longitudinal
thoracic muscles continue along the side of the
abdomen, On the thorax, these muscles tend to
forma rather regular meshwork with the internal
circular muscles. Moderately conspicuous sphinc-
ters aye around the siphons. There are about l6
stigmata per row. The abdomen is of the usual
form with gonads in the gut Joop, The testis
follicles sometimes form 4 fairly compact, almost
spherical mass of follicles at the side of the distal
end of the gut loop, but sometimes are loosely
disposed in the gut loop.

Up to 4 developing embryos are lined up,
overlapping one another in the peribranchial
cavity. Larvae, which are in beth holotype and
paratype colonies, have an elongate trunk 0,75mm
long with relatively long tail wound about two-
thirds the Way around it. A row of 4 rounded
lateral ampullue is along each side of the median
adhesive organs at the anterior end of the trunk,
Phe ventral pair are Mattened plates on a long
buse.

Remarks: The larva of this species, with its
long trunk. and narrow plate-like ventral ectod-
ermalampullie, 1s distinctive. However the adults,
especially after preservation, have few distinguish-
ing characters except the evenly distributed
spherical pigment cells and upright colonies.

Eudixstoma glaueum has sinnlar stalked heads
and zooids, although the present species lacks its
preen pigment. Huclivfoma globosum has a similar
colony but lacks the circular systems. The larval
trunk of E tierum asp. is the same size as the
present species, but its colonies are flat sheets
rather than upnght lobes and it has a distinctive

MEMOIRS OF THE QUEENSLAND MUSEUM

volour pultern im the surface Lest. Preserved
colonies of the present species have a white
suspension in the surface, and accordingly it can
be conlused with A. unaematun asp. which is
distinguished by its low. cushion-like colonies
without stalks, smaller pigment cells, and longer
atrial siphons. Eudivtama muscasum nom. nov.
has a similar compact spherical mass of testis
follicles, but it has more crowded and larger
pigment cells, lacks both the stalk and white
surface suspension characteristic of the present
species, and its preserved 2ooids are more intensely
coloured, being reddish-brown rather than pink
to cream, One long-preseryed specimen. possibly
this species, from Heron 1, (QM GH4851) has lost
all colour except for a wide collar of spherical
orange vesicles around the duodenum.

Eudistoma microlaryum n.sp.
(Fig, §3c,d)
Disreisuiice

Tyrer Locauty, Queensland (North Stradbroke L..
Point Lookout, near low tide mark, coll. A. Rozetelds
17.11.78. holotype QM GH4520) pucutypes QM
GH4521),

Furnture Recowos Queensland (Hervey Hay, OM
GI11938).

‘The spectes has so tar been reearded only in sandy
habitats, from ¢@ smi! part of the southern Queensland
coast,

DEseRIPTION

Exrheenarn Apenarancr: Colonies are [Mat
investing sheets or cushions, up to |.5em high.
and sometimes with the naked upper surfuce
divided into irregular lobes. ‘The test is almost
transparent and although it has sand grains
embedded, the sand is relatively Sparse in the lower
hall of the colony und sometimes absent [rom the
upper half around the thoraces of the zowids.

The small zooids, which are 4mm long when
extended, are white und (hread-like in preserva-
tive, and can be seen extending vertically through
the transparent test. They do not form systems.
The separately opening atrial and branchial
apertures can be demonstrated by washing a drop
of stain across the surface of the colony.

INTERNAL StRUciuME: Both the branchial and
atrial siphon are relatively short, each with a shart
splineter. Thoracic museles wre fine, about 12
longitudinal bands and only about 14 transverse
ones. Longitudinal museles extend slung each side
of the ventral hall of the abdomen well separated
fram one another, They are not gathered into a
continuous wide bund. There are only about &
stigmata per row, The oesophageal neck iy long
and narrow, and the small, smooth-walled

THE AUSTRALIAN ASCIDIACEA 2 219

Mongol Mies

roy?

Fic. 83, Eudistoma malum n.sp.: a, zo0id (QM GH46338): b, larva (holotype QM G11939). Eudistoma microlarvum
nsp. (holotype QM GH4520): ¢, colony; d, zooid; e, larva, Scales: a,d, 0.5mm; b,e, 0.1mm; ¢, 5mm.

220

stomach is in the posterior end of the abdomen.
The duodenal area is long and tapers to a small.
oval, posterior stomach at the posterior end of
the descending limb of the gut loop.

A long, grape-like cluster of male follicles at
the left side of the gut loop slightly overlaps the
pole of the gut loop, The type material, has a
single embryo in the atrial cayity, mature male
follicles and the vas deterens filled with sperm and
expanded into a long spindle-shaped seminal
vesicle at its proximal end.

The larva is small with a trunk about 04min
jong, Tt has Isteral as well as median ampullae,
an ocellus and otolith.

Rimarks: Colonies of this species are readily
distinguished frum Madistoma cornsirictum (which
also is sandy, investing and lacks systems) by its
small thread-like 2ooids,

Eudistoma museosum nom, nov,
(Fig. 84)
Polyetior mollis Studer, O09 pL 1!
Not Distoma male Ritter, (900, p. 605, — Ludiytonta
molle: Van Name, 1945, py, 128

Disrmimtirinis

New Recorps. Qocensland (Caphean Group, OM
Gli94) GU944 7 GIES49 GH4568 78, Lizard 1. OM
(FH4592 AM Y2207).

Purvieusiy Reeowden Indonesma (4MA 'PU8OT
Sluiter 1909),

Desc rir hton

Exreenal Arrrawanen, Most colonies are
smooth, shiny and round to Jovenge-shaped or
irregular pillows about one to 2em in maximum
extent and up to 0.50m high. They are fixed by
most of the basal surface. The colony from Lizard
1, (AM. ¥2207) Is larger. It is an upright lobe at
leastSem high and 4cm in diameter, In life colonics
occur in a variety of colours in the range khaki,
olive to brown (Ridgeway L886: “tawny-olive,
‘sepia’, ‘wood-brown', “mustard-green”, ‘cloye-
brown’, ‘olive’, ‘olive-green’, ‘bay’. “bisere’y.
Oceasionally the colour shades from brown at one
end to tawny ohve al the other. In preservative
the colour becomes black-brown or brown, and
later 1 cloudy greenish-grey, In freshly preserved
material a mass of opaque tan-coloured pigment
cells (U0.04mim in diameter) pack in the test at
thoracic to oesophageal level, below the surlace
of the colony. Also minute (0.02 to 0.03mm) shiny
reddish spheres are scattered im the test. The
preservative stains reddish to brownish-vellow. In
freshly preserved material zooids are black,
although this persists only in the anterior part of
the thorax. Zooids, especially in the endostyle,

MEMOIRS OF THE QUEENSLAND MUSEUM

gut and ponds, usually become the reddish-brown
colour of the preservative. The test is relatively
transparent in preservative and is soft Sand and
faeeal pellets embed in the test in the base of the
colony, Zooids are ip eircular systems af about
5, with their atrial apertures near one another in
the centre of the circle,

Intteaar Steecrurge. Zooids are large (up to
5mm long even when contracted) usd robust. The
oesophageal neck is relatively thick. The atrial
siphon is 2 to 4 times longer than the branchial
siphon, and both are relatively wide. Strong
circular muscles surround cach siphon fairly
evenly along their length, There are about 20
strong thoracic longitudinal muscle bands and
more numerous cirenlar ones. Longitudinal bunds
continue along cach side of the abdomen
separately and ure not gathered into a band. They
lerminate just posterior to the stomach on each
side of the mid-venteal Jine. Thus, when contracted
the ocsophageal neck is shortened, the oesophagus
and reetum are horizontally wrinkled and pleated,
but the posterior end ol the gut loop is not much
affected. About 25 stigmata are in the anterior
row and only 18 in the posterior row. The dorsal
part of the anterior row of stigmata curves forward
along each side of the dorsal mid-line.

A long duodenal area and a distinet oval
posterior stomach lie in the posterior part of the
descending limb of the gut loop. Long tubules
ol the gastro-intestinal gland curve around part
of the rectum opposite the duodenum, In
specimens collected in November the testis follicles
are mature and form a large, compact spherical
muss On the left side of the posterior end of the
gut loop. The vas deferens is conspicuous with
a lang, spindie-shuped expansion packed with
sperm as it extends anteriorly dorsal to the rectum.

One or 2 embryos are in the atrial cavity of
specimens collecied in August (QM GH1J349) and
January (QM GH4568). The larval trunk is almost
spherical, and about Imm long. The 3 adhesive
organs are of different sizes. Each hus a wide.
slightly elongated platform of adhesive cells,
surrounded by w shallow ectodermal cup. The tail
is Wound about three-quarters of the way around
the trunk. The larval epidermis contains dark
pigment concentrated in the 2 posteriorly
projecting horns of the larval haemocoe| — one
each side of the base of the tail. These larvae have
3 rows of stigmata.

Remarks: Living specimens ure distinguished
by their brown-khakt- olive green colour, but in
preservative by the soft translucent test, minute,
shiny, spherical (red in preservative) and opaque
tan pigment cells, the large compact spherical mass

THE AUSTRALIAN ASCIDIACEA 2 221

iy om

Pic. 84, Budtstoma muscosum nom. nov= a-c. zooids showing various positions of the atrial siphon (QM GH457
GH1349 GH4570); d, thorax, showing dorsal end of row of stigmata continuing alongside mid-dorsal line
(QM GH4568); e, larva (QM GH4568), Scales: a-d, 0.5mm; e, 0,]mm.

222

of tests lollicles and the reddish-hrown uc black
zooids.

The type specimen (AMA TU-80}) is a soft,
fleshy, sessile cushion from which mast of the
colour is boOW lost leaving the test almost
transparent. Some brown pigment remuins in Lhe
vooids around cach of the apertures. Zooids are
robust with a large compact mass of male lollicles
as inthe newly recorded material, Although Sluiter
recorded fewer stigmata, there are at least 15 in
the type specimen, the exact number being difficult
to determine owing to the contracted condition
of the zoids.

Long-preserved colonies in which the colour has
faded altogether can be confused with Ewdisrama
purpureum nsp. although the latter spectes has
larger larvae, Exclistoma tigrum nsp, also has
robust coords and looses its colour in preservative,
but has sheet-like rather than cushion-lke
colonies, and smaller larvae with flattened leaf-
like ampullae and small, narrow-stalked adhesive
organs,

The accumulation of dark pigment in the 2
posterior horns of the larval haemocoel is
reminiscent of the angolanum group of ELudis-
toma, although these have more ampullae than
the larvae of the present species,

Eudistoma ovatum (Herdman, | 884)
(Fig. 85a-f)
Psammaplidum ovarun Herdman, (886, p. 246,
Eudisiome vvalunr Hastings, 1931, p 42, Kort. L972e.
p. 43 (part, specimen trom S{. 773),

Polyetrar arenaceus Sluiter, 1909, p. 13.
Palyeitor scaler Slutter, 1909, p, 25
Eudistoma pyrifarme: Vokioka, 19674, po 110,
? kudistoma vulgare Monniot, L988, p. 215.

Dis Pa BU TtON

Nw Receorps: Queensland (Hervey Buy. OM G9269
GI193K GH4594; Tannum Sands. QM GH4595 6;
Capricorn Group, QM GIl96% GII97T! GH4ASOX-Y
GH4601 4; Yeppoon. QM GH4597; Redbill 1. QM
GH4600; Lizard 1, OM GII970.

Previousiy RecoKrbrm, Wester Australa (Cape
Boileau Hiustings 1931). Queensland (Low Is OM
G13510 Hastings 1931). Nerthern Australia (Vorres
Strait = Herdman 1886; Gull of Carpentarit AM
YI060 Kott 1972e). Indonesia (AMA TUS05S type £
scaber Sluiter, 1909). Palau and Gilbert Is (Tokioka
1967),

Description

External Arrrearnancy: Colomes are firm
encrusting sheets, up to lem thick. They grow over
irregulacities i the substrate §0 that the surface
appears raised into lobes and swellings. Otherwise
the surface is even, without prajecuons or

MEMOIRS OF THE QUEENSLAND MUSEUM

depressions, Sand is evenly distributed throughout
the otherwise colourless and Lransparent test, but
possibly is less crowded wt thoracic than at
abdominal level. Faccal pellets are also in the test,
Zooids ure pink, with a brownish stomach,

Zooids are in circular systems, 2.5mm in
diameter with up to 7 zooids per system. Zooid
openings are reasonably conspicuous owing Lo the
interruption of the sand where each opens to the
surface. They are evenly spaced at the surface but
internally abdomina cross one another irregularly,

InvernaL Srevuerure&: Zooids are relatively
small, the contracted thorax being quite nurrow
and only [mm long, The atrial siphon is long and
muscular, The branchial siphon also is Well
developed with a wide band of branchial tentacles
Branchial and atrial lobes are rounded. About 12
to 25 thoracic longitudinal muscle bands overlie
about 30 transverse ones. Longitudinal muscles
continue in two long bands on each side of the
abdomen. Often the whole abdomen is folded up
against the thorax owing to the strong contraction
of the ventral body muscles. There are at least
20 stigmata per row.

Gonads, stomach. and the usual divisions of
the gui distal to the sLomach, are in the posterior
end of the abdomen, They are obscured by the
contraction of these small zooids, in which the
oesophagus is wrinkled and rectum kinked and
Iwisted along the whole length of the zoard.

Up to 5 embryos are in the atrial cavity of
specimens collected in April from central Queens-
land, in April, May and October from Heron 1,
and in July from Redbill J. (QM GH4595--9
CG H4604 GH4600). Larvae are small, the trunk
only 0.6mm long. The tail winds almost three-
quarters of the way around the trunk to the left
of the adhesive organs. Three slender-stalked
adhesive organs are in the median line anteriorly.
Dorsal and ventral median ampullae each have
a parietal branch on each side. Each of the 2 lateral
ampullae on each side also have a parietal branch
near the base, Fine projections from the ectaderm
around the apertures extend into the larval test.

Rumarks: The other sandy species of Eueliy-
toma known from tropical waters in which the
vooids are in simple circular systems without
actual cloacal ecavitics are E. antplum and E.
pyriforme, The latter has pyriform colonies that
distinguish it from the present species. Eudisroma
amplum has large zooids and larvae and contains
large, spherical symbionts in the test. as well as
the sand, and the sand is seldom evenly distributed
as itis in the present species.

The sandy temperate species £2. subuloyym, has
thicker colonies than the present species, the

THE AUSTRALIAN ASCIDIACEA 2 223

Fic. 85, Eudistouma ovatum: a, circular systems seen from the surface (QM GH4596); b,c, thoraces with incubating
embryos (QM GH4604); d,e. gut loops from contracted zooids (QM G11969); f, larva (QM GH4595). Eudistoma
pratulum n.sp.: ga system of zooids from the surface (paratype QM GH4607); h, zooid (holotype QM GH4606).
Scales: a, 2mm; b-e,h, 0.5mm; f, 0.lmmy; g, 1mm.

224

surface of the colany is net as smooth and lhe
euuids ure stnaller, with not more than LO stigmata
per row,

Hastings (1931) coneluded there were 3 sandy
species of Ludisioma trom Australian waters, wis,
& ovarum (Herdman, 1886). 2 angelanunr
(Michaelsen, 1914) and & pyriforme (Herdman.
1886), She compared a large (loem wide and Yem
high) colony trom Cape Boileau, north-western
Australia (that resembles the newly recorded
material) with the type specimens of £. avalum
Herdman.. |886) and a smaller specimen from the
Great Bareiet Reef. and considered all 3 af these
specimens to be conspecific. A purt of the Great
Barrier Reel specimen examined by Hastings 1s
in the Australian Museum (AM YI3510). Tt
appears part of the colony (bisected along the
longitudinal axis) figured by Hastings (1931, p.
$5, text fig, Se), In this specimen the test ts
iMpregnated With sand, Zooids Open all alone the
surface. und although a lew abdomina run parallel
to the long axis, most lic almost perpendicular
io the surface and cross One another. le appears
a slice off the surface of a larger colony rather
than a portion of a stalked one.

Eudistoma vulgare Monmot, (988 has similar
eolony, zooids and larvae Lo Those of the present
species and appears a synonym

Although Po/tetur seaber Sluiter, (909 was
reporied to have only 6 or 7 stigmata per row,
reexamination of the single known specimen
(4MA TUS0S) has showt it to have a similar
number to that tound in the newly recorded
specimens, With an equally wide band of branchial
tentacles and the sandy colony characteristic of
this species.

The fine ectodermal projections into the larval
fest around the apertures occur in many Edis
lume spp. (sce Annotated Glossary: larvae).

Vudistoma pratulam nsp.

Dis remuvios (Fig. 85g.h)

fyer Loe vciey; Queensland (Heron {.. ribble fauna.
low waiter mark, coll, PB, Kou May 1987, holotype OM
GH4606, Heron |, Blue Pools rubble fauna. coll, PK
9.1 LOS. paratype OM GH4607).

Forture Rrookes. None,
Dts Le) boa

UxivenaAt Arrvarancr: Colonies dre large (up
to Sem long, 4em wide and about len thick) firm
bul fleshy and rather irregular sheets. In life they
ure creamish or ‘save-vreen’ with ‘pea-green’zooids
(Ridgeway 1884), slightly translucent and with a
slightly rough rather than smooth surface, In
preservative the lest is brownish-grey, sometimes

darker at ane end than the other as a result of

MEMOIRS OF THE QUEENSLAND MUSEUM

ibe crowding of miuiule dack pigment cells. Zooids
are brownish-cream in preservative, the stomach
brown and the embryos orange. There are shiny
brown pigment celly 0.02 to 0.03mm in the test
and [ving in the space between the zooid and the
test, probably released in blood from severed
vessels. Same white suspension, similar to that
found in Eudistoma anaematuni n.sp.. is in the
surface test, and large pools of dark pigment cells
are in the basal test, Zooids are arranged in circles
of 5 of 6,

Int ekAAL Sreueturr Zooids are of moderate
size, about Smm long ina fairly relaxed condition,
The atrial siphon is often much longer than the
branchial siphon. The sphincter muscles wound
cach aperture are narrow and not conspicuous.
About [0 to 12 fine longitudinal thoracic muscles
continue along each side of the abdomen if several
bands. About 25 fine circular muscles are on the
thorax. Branchial tentacles are confined to a
Harrow zone at the base of the branchial siphon,
und are in 3 circles, Lentacles are mot numerous,
about @ larger ones are in the outer circle, 6
moderate-sized ones imthe second circle. and more
numerous and irregularly distributed smaller ones
in the anterior circle, Stigmata number 25 in the
anterior row, which curves anteriorly along, each
side of the mid-dorsal line, but only 18 in the
posterior row,

The gut has the usual subdivisions found in this
genus, The oval posterior stomach is well defined,
Large pyriform testis follicles are tucked inte the
pole of the gut loop of specimens collected in May
(QM GH4606), A single embryo up to 0.75mm
long is in the atrial cayity of the zooids of this
specimen, although mature laryae were not
developed and their structure is not known.

Rimanes: Although these colomes are green.
sometimes with green vooids, they are nat the same
opaque shiny green of Budistoma glaucyum. The
extensive, fat, irregular translucent colonies with
a rather rough surface also distinguish them trom
Be planeum and &. pitycosum nom. ooy, The latter
species also has spherical pigment cells. about the
sume diameter as those in the present species.
However. the larger. crowded. granular-looking
din cells of £. muscosum nom, noy. are not present
in & pratulum. Zooid colour in preservative is
also different — E muscosuwm nom, nov, has
brownish-red zooids the present species grecnish-
cream to brown ones. Euidistonia anaematumn does
not bave the shiny, spherical cells of the present
species. Although the larvae of &. pratudunt are
not known, large embryos indicate the larval trunk
could be at least 0.75mm long, Le, similar to £,
MIMSCOSUML TOM, TOY.

THE AUSTRALIAN ASCIDIACEA 2

Eudistoma purpureum n.sp.
(Fig. 86)

DisTRIBUTION

Type Locaciry: Queensland (Wistari Reef, under
rubble near reef edge, coll, P,Kott 1.11.86, holotype QM
GH4466; 30.10.86, paratype QM GH4467: Heron L.,
January 1983, paratype QM GH4455).

Furraer Recorps; Queensland (Capricorn Group,
QM G11972-6 GH4456-65 GH4481 GH4484 GH4491
GH4561 GH4567 GH458!1 GH4585).

DESCRIPTION

ExTERNAL APPEARANCE: Colonies are sessile
cushions, fixed by a flat base, rounded on the
upper surface, usually 2 to Sem in diameter and
up to 2cm high. Only occasionally is the colony
divided into 2 or 3 lobes arising from a common
base. Living specimens are completely opaque,
‘indian-purple’ or ‘hyacinth-blue’ (Ridgeway 1886)
in colour, the surface smooth and shiny. In
preservative colonies are grey-black to cloudy-
grey, and sometimes the test becomes translucent
with darkly pigmented greenish-black zooids
showing through it. Minute dark pigment cells
are scattered through the test, but are especially
concentrated around the zooids, and in the body
wall. Also small cloudy crowded test cells confer
a cloudy appearance especially evident in the upper
layer of test.

Four to 6 zooids form circular systems with
the atrial apertures opening in the centre of the
circle. Zooid openings are relatively inconspicuous
on the surface and no depressions or other marks
are on the surface.

Sand is in the base of the colony and sometimes
extends up into the centre of the base of the colony,
but never reaches the upper half. Oval faecal pellets
in varying quantities are in the test, which is
gelatinous and soft but turgid.

INTERNAL STRUCTURE: Zooids are about 6mm
long, and the thorax is relatively wide. The atrial
siphon is often up to 3 times the length of the
branchial siphon. Variable concentrations of
minute dark pigment particles are in the body wall.
There are about 12 longitudinal thoracic muscles
and more numerous circular ones. Circular
muscles are along each siphon,

In the pharynx is a fairly extensive prestigmatal
zone, and about 20 stigmata in each row, the most
ventral ones reducing in length. Dorsal stigmata
in the anterior row also are reduced in length and
the row curves anteriorly along the mid-line to
reach up along each side of the neural ganglion.

There is the usual long oesophageal neck. The
smooth-walled stomach is in the posterior end of
the abdomen, and a long duodenal area, but the
posterior stomach is not well defined and often

225

the mid-intestine appears uninterrupted. The
rectum originates in the pole of the gut loop. The
gastro-intestinal gland consists of long tubules that
branch from the main stem of the duct near its
origin (at the pyloric end of the stomach), and
extend around the rectum at a level with the
stomach.

Gonads are found maturing in specimens
collected in October and November. Male follicles
are relatively large and pyriform, and a large ovum
is at the side of the gut loop. The vas deferens
is particularly conspicuous, dark-greenish in
preservative,

One or 2 embryos are in the atrial cavity of
specimens collected in late October (QM GH4467),
November (QM GH4457 GH4466) and January
(QM GH4455). Larvae are large, the trunk 1.5mm
long, with the tail barely reaching to its anterior
end, Large median ampullae alternate with the
adhesive organs, and accessory ampullae arise as
lateral bract-like expansions from the stalk of each
adhesive organ. Larvae have 3 rows of stigmata,
as do those of £. maculosum n.sp. and E.
purpureum n.sp. Fine ectodermal projections into
the larval test surround the apertures as in E.
ovatum and other species (see Annotated Glos-
sary: larvae).

Remarks: Living, the species is distinguished
by its brilliant, opaque, purple colour, smooth
shiny surface and entire (rather than lobed) colony.
Preserved specimens are distinguished by the
absence of symbionts (present in £. amplum),
smooth, round, sessile colonies, absence of any
red or orange, and dark-greenish zooids. Muscles
of the atrial and branchial siphons are not
concentrated into a distinct bulging sphincter as
in E. angolanum (see above) and sand is only
sparse in the base of the colonies.

Tokioka (1967a) assigned specimens from the
Marianas and Gilbert Is to £. angolanum. These
specimens are diverse — some have embedded
sand, others do not; some have vesicles in the
surface test while others lack them and there are
from 12 to 20 stigmata and 10 to 30 longitudinal
muscles. The lack of characteristic siphonal
sphincter muscles in any of Tokioka’s specimens
suggests these may not be conspecific with E.
angolanum. The range in all characters recorded
by Tokioka suggests his material represents more
than one species. It could include specimens of
E. purpureum. However, zooids are reported
yellowish-orange or reddish-brown, the dark
colour of the vas deferens is not described, and
larvae have more numerous epidermal ampullae
than the present species. Thus, at this stage EF.
purpureum cannot be positively regarded as

226

MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 86, Eudistoma purpureum n.sp.: a, zooid (paratype QM GH4467); b-f, thoraces showing various positions
of the atrial siphon (QM G11974); g,h, larvae at successive stages of development (QM GH4457). Scales:

a-f, |!mm; g,h, 0.2mm.

conspecific with any of the previously recorded
species of the genus Eudistoma.

Eudistoma maculosum n.sp. (> E. renieri: Kott,
1957a) from Cockburn Sound has larvae with the
same bract-like accessory ectodermal ampullae as
the present species. However, its larvae are smaller
and the colonies sheet-like with a distinctive colour
pattern — although that is not conspicuous in
the preserved material. Eudistoma marianense
Tokioka 1967a also has similar larvae to those
of the present species but it appears to lack the
lateral ampullae.

Eudistoma pyriforme (Herdman, 1886)
(Fig. 87a)
Psammaphlidum pyriforme Herdman, 1886, p. 419.
Eudistoma pyriforme: Tokioka, 1950, p. 120. Not Kott

1957a, p. 75 (> Eudistoma sabulosum n.sp.); 1972b
(> E. aureum n.sp.); 1976, p. 58 (> Eudistoma
sabulosum n.sp. and E. maculosum n.sp.)

DistTRIBUTION
New Recorbs: Queensland (Bargara, QM GH4552).
Previousty Recorpep: Queensland (Torres Strait
— Herdman 1886). Palau Is (Tokioka 1950).

DESCRIPTION

EXTERNAL APPEARANCE: The colony has rather
irregular, rounded to flat-topped lobes joined to
common basal test. They are up to 2cm high, one
to 2cm in diameter on the upper free surface, and
they taper slightly toward the base. The test is
packed with sand which obscures the circular
systems, each of about 6 zooids, opening on the
upper surface of the head. Zooids are white in
preservative.

THE AUSTRALIAN ASCIDIACEA 2

ta
tw
~~

Pic. 87, Eudistoma pvriforme (QM GH4552): a. colony. Eudistoma reginum n.sp. b, view of surface showing
branchial epertures surrounding cloacal depression and vesicles in the test (QM G1 1951): ¢. zoaid (QM GH4489),
d, dorsal view of abdomen (OM GH4489): e. larva (QM GH4489), Scales: a, Smm: b, Imm: ed. 0.5mm;
e, 0.2mm.

InreRNAL Appearance Zooids are relatively
small, about 2.5mm when contracted, They have
5 to 10 widely separated longitudinal muscle bands
on the thorax, and these continue along the
abdomen in a single wide band on each side. The
atrial siphon is longer than the branchial siphon.

The gut has the usual rounded stomach. long
duodenal area, and large oval posterior stomach.
In contracted zooids, the intestine makes a
horizontal loop across the abdomen behind the
stomach,

There ure no embryos in the newly recorded
specimen (collected in May),

REMARKS: [he present species is distinguished
from other sandy species by its separate Jobes.
rather than flat, investing colonies. It resembles
E. glohasuni to some extent however. in the
latter species, zo0ids are more crowded, are nol
in circles, colony lobes are more rounded than
flat-topped. and the surface test over the head of
the colony is always tree of sand.

228

Eudistoma reginum n.sp.
(Fig. 87b-e. Plate 16e,f)
2 Eudistoma amplum: Millar, 1975, p. 219 (part,
specimen from Toeal with cloacal cavity).
DistTRIBUTION

Typr Locatiry; Queensland (Heron I,, on underside
of rubble behind reef edge LWM, coll. P.Kott March
1975, holotype QM G11948; Heron [., coll, P.Kott
September 1976, paratype QM G11950; Wistari Reef,
coll. P,Kott July 1976, paratype QM G11949; Tryon
Reef, coll. P.Kott September 1975, paratype QM
G11951).

Furtuer Recorps: Queensland (Capricorn Group,
QM G11969 GH888 GH4447-51 GH4485-90 GH4492
GH4522-6 GH4580 GH4586; Lizard I., QM G11966).
DESCRIPTION

ExTERNAL APPEARANCE; In life the colonies are
‘aster purple’ (Ridgeway 1886) and form smooth-
surfaced cushions to sheets from about 3 up to
20cm (QM GH4524) in maximum extent and from
0.5 to about 2cm thick. Preserved they are
brownish-orange, hard, flat and rather leathery.
The preservative is stained a bright orange. The
border of the colony is rounded and slightly raised
above the upper surface. Sand is in the base of
the test and in patches throughout, sometimes just
beneath the upper surface. In some colonies a
sandy border around each system is seen through
the reddish-purple test. Occasionally sand grains
are crowded. Small spindle-shaped dark pigment
cells in the test immediately surround the zooids.
Large (0.3mm diameter) vesicles are present at all
levels through the test, particularly conspicuous
(but never crowded together) in the upper surface
between zooid openings. They contain crystalline
material. Small, tan, soft-looking, opaque,
pigment cells are crowded between the large
vesicles. Oval faecal pellets are also in the test.

About 7 or 8 zooids are in each circular system.
The systems are about 3mm in diameter. Most
of the atrial apertures are close together around
the edge of a depression in the centre of each
system. Others open in the centre of the depression,
and are not associated with its rim. The 3 anterior
lobes of those atrial apertures around the edge
of the depression are inserted into corresponding
lobes of the test around the rim which projects
inwards, over the depression, to form a lobed
cloacal aperture over a rudimentary cloacal cavity.

INTERNAL StRucTURE: Flecks of orange pig-
ment in the body wall of zooids and embryos
colour them orange. Zooids are robust but
relatively short (about 4mm long contracted) and
narrow with strong musculature consisting of
about 20 longitudinal bands on the thorax.
Circular muscles are more numerous forming an
almost continuous coat. Circular muscles on the

MEMOIRS OF THE QUEENSLAND MUSEUM

siphons are strong, evenly spaced along the length
of the siphon, and not gathered into a distinct
band. The posterior end of the abdomen often
is found bent up sharply against the anterior part
of the zooid.

Stigmata are about 16 in each row, but are
difficult to count. The stomach is small and
smooth, the duodenal area long. A large, oval,
posterior stomach, separated from the rectum by
a short constriction in the pole of the gut loop
occupies most of the mid-intestine. Thin-walled
terminal ampullae of the gastro-intestinal gland
surround the rectum and duodenum in many
specimens.

Gonads are a mass of pyriform follicles, with
a large egg on the left side of the gut loop. Two
or 3 embryos are in the atrial cavity of specimens
collected in October and November (QM GH4448
GH4450). However, maturing gonads occur in
May (QM GH888). Thus, it is possible there are
two breeding seasons.

The larval trunk is Imm long with a short tail,
barely reaching the anterior end of the trunk.
Larvae are unusual in having patches of brown
pigment in the posterior horns of the haemocoel
— one on each side of the base of the tail, and
in the stalks of the adhesive organs. Ampullae
are only in the mid-line between the adhesive
organs, one between the 2 upper ones and 2
between the 2 lower ones.

Remarks: Like others in the angolanum group,
E. reginum has large vesicles in the test containing
crystalline material, circular systems with a
shallow, rudimentary cloacal cavity, anterior lobes
of the atrial apertures inserted into the test around
the perimeter of the cloacal cavity and folding
inwards to form a rudimentary cloacal aperture,
and unusual brown pigmentation in the larval
haemocoel.

The species has much smaller cloacal systems,
shorter siphons, usually less sand in the test, and
shorter larval trunk than Eudistoma carnosum
n.sp. Eudistoma angolanum has a red test packed
with embedded sand, zooids with long, snake-like
atrial siphons with a bulging sphincter muscle, and
larvae with numerous lateral ampullae. Eudistoma
multiperforatum (Sluiter, 1909) has tough
investing colonies with red test, sand embedded
in the basal half of the colony and preserved
colonies resembling those of the present species;
but its zooids are not arranged in circles, and the
atrial siphons are short (see ZMA TU809.1,
TUS809.2).

Eudistoma muscosum nom. noy, also has dark
pigment in the posterior horns of the haemocoel
but lacks the cloacal cavities in the test.

THE AUSTRALIAN ASCIDIACEA 2

Eudistoma sabulosum n.sp.
(Fig. 88. Plate 16g)

Eudistoma pyriforme: Kott, 1957a, p. 75 (part, specimens
from Port Noarlunga); 1976, p. 58 (part, specimen
from Western Port).

DISTRIBUTION
Type Locariry: South Australia (Topgallant I., 5m,

coll. N. Holmes 29.3.82, holotype QM GH937; Ward

I., 1-5m, coll. N. Holmes 31.3.82, paratype QM

GH4591).

FurtHer Recorps: South Australia (St, Vincent
Gulf, QM GH4588). Victoria (off Lakes Entrance QM
GH4587; Bass Strait. MV F54583, QM G11864 GH4589;
Western Port, MV F53405, QM GH4590).

Previousty Recorpep: South Australian (St.
Vincent Gulf AM Kott 1957a). Victoria (Western
Port — MV Kott. 1976),

DESCRIPTION

ExterRNAL APPEARANCE: Colonies are sessile
rounded to irregularly-shaped cushions with
rounded borders, up to 4cm in diameter and 2cm
thick. Colonies are solid. The test, especially in
the outer layers, is packed with sand which
dominates the colour of the colony. The upper
surface, subdivided into protuberant, rounded
swellings, resembles a cauliflower. Zooids are in
circular systems, about 5 per system. The atrial
apertures in the centre of the circle open onto
slight conical elevations. The branchial apertures
are in depressions around the base of these
elevations.

Between the sand, the test is colourless in
preserved specimens. Abdomina of the crowded
zooids criss-cross one another, but thoraces lie
parallel, with only thin layers of test separating
them. Thus, when the zooids are contracted, the
upper layer of the colony has a rather loose
consistency. The crowded sand makes the test
hard, enclosing rigid compartments that contain
the zooids.

INTERNAL StRucTURE: Zooids are relatively
small and muscular. Short and inconspicuous
sphincters are around the apertures. The atrial
siphon is longer than the branchial siphon. There
are about 30 longitudinal thoracic muscles and
an almost continuous layer of circular muscles.
Stigmata are only 8 to 10 per row. The gut has
the usual smooth, round stomach, long duodenal
area, and oval posterior stomach, In contracted
individuals, the intestine forms an S-bend or
horizontal loop just posterior to the level of the
stomach. Sometimes the whole posterior end of
the abdomen is bent up against the zooids. Up
to 6 embryos are in the atrial cavity of specimens
collected in January (Kott 1957a). The larvae are
small, the trunk being 0.5mm long. The tail is
wound three-quarters of the way around it.

229

XS

Fic. 88, Eudistoma sabulosum, n.sp.: a, section through
colony showing arrangement of zooids (holotype QM
GH937); b, thorax (QM G11864); ¢, larva, dorsal view
(QM GH4588). Scales: a, 2mm; b, 0.5mm; c, 0.1mm,

Adhesive organs have long, narrow stalks. There
are 2 pairs of long lateral ectodermal ampullae,
and unpaired ampullae dorsal and ventral to the
adhesive organs in the mid-line, but no median
ampullae alternating with adhesive organs.

Remarks: The species is distinguished from the
tropical Eudistoma ovatum by its irregular,
cauliflower-like upper surface, the slight conical
elevations supporting the atrial apertures above
the surface of the colony, and its smaller zooids
with only about 10 stigmata. Zooids of both
species contract in much the same way, with, in
extreme cases, the abdomen folded up against the
rest of the zooid. Larvae of both species are small,
although the tropical E. ovatum has median as
well as lateral ampullae, while the present species
lacks the median ampullae that alternate with the
adhesive organs.

Eudistoma constrictum n.sp., another sandy
species from temperate Australian waters, lacks
the circular systems of the present species and has
a much larger larva.

Eudistoma superlatum n.sp.
(Fig. 89)
DistRiBUTION
Type Locattry: Western Australia (Shark Bay nr.
South Passage, 10-15m, coll. L, Marsh 8.4.79, holotype
WAM 822.83 OM GH2/36; Abrolhos Is, Easter Group,
coll. P. McMillan 16.5.63, paratype WAM 189.75).

230

Furrner Recorms: Western Australia (Montebello
Is. WAM 770.83; ? Port Hedland, WAM 769.83;
Houtman’s Abrolhos, WAM 768,83).

Drscriprion

Exterwat Appearance: The holotype colony
is massive and fleshy. Scm long, 6cm wide at the
base, and 6cem high. It is fixed to the substrate
by the whole of the base. The upper part is divided
into 10 lobes, each lobe oval in section, No zooid
systems are formed. The test is firm and gelatinous.
more or less opaque and crowded with cloudy
cells that are pinkish-beige in preservative. Zooids
are crowded, pink in preservalive. and both
openings dre in inconspicuous circular areas of
thin test all over the outer surface of the lobes
and the sides of basal half of the colony. The outer
surface of the colony is completely naked, and
although faecal pellets are embedded in the test,
there is no sand. The paratype colony is a single
oval head about Sem long and 4em in diameter
with a short, thick fleshy stalk.

INTERNAL SyrucTURE: Zooids are up to about
2em Jong. They are slender and have a long,
delicate, posterior abdominal vascular extension.
When contracted the gut is folded up into a wide
loop that projects [rom the side of the abdomen.
However, in extended zouids there is the usual
long oesophageal neck, Both apertures are at the
anterior end of the zooid. The atrial opening is
sometimes on a long siphon, but the branchial
aperture is almost sessile. About 20 fine longi-
tudinal muscle bands are on each side of the
thorax. These continue along the abdomen in
about 3 wide bands which converge into a small,
pointed projection on each side of the base of
the musele-free vascular stolon. About 40 fine,
transverse muscles on the thorax, form a fine mesh
with the longitudinal muscles,

The branchial tentacles are in at least 3 rows.
The prestizmatal area of the pharynx is only
shallow. The anterior row. which inclines forwards
along each side of the mid-dorsal line has 34 long
stigmata, 26 in the middle row, and about 24 in
the posterior row. The small, smooth stomach,
Jong duodenal area, and oval posterior stomach
are all in the posterior end of the abdomen as
is usual for the genus.

No gonads were detected in the holotype,
although they are present in the gut loop in the
paratype, which also has a single embryo in ihe
atrial cavity — protruding slightly from it in these
contracted specimens. The delicate and long,
posterior vascular stolon in this species may be
associated with the large size of the colony.

Remarks, Although E£udixstoma contains
species with extensive sheet-like colonies, it has

MEMOIRS OF THE QUEENSLAND MUSEUM

Fic. 89, Budixioma superlaium a.sp.; a, colony (holotype
WAM 822,83); b-e, zoids (holotype QM GH2136);
f, first row of stigmata on left side. Seales: a, 2cm:
b-e, Imm; Ff, (.5mm-

THE AUSTRALIAN ASCIDIACEA 2

few species with massive, bulky and Heshy lobed
colonies like the present species, In this, the specics
resembles Sigillina spp. and Pseudodistoma spp.
Stgilina fantasiana and S. nigra resemble the
present species in lacking the usual sigillinid
muscle fibres and epicardial extension respectively
on and in the vascular stolon. However, zooids
al the present species ure smaller than those of
Sivgillina spp.. and they have the longer oesopha-
geal meck of Enelistoma, Vhe heart ts at the
posterior end of the abdomen, rather than in the
posterior abdominal extension as it is im Pyen-
dedistoma. Eudistoma glaueum is the only other
known species of Eucivtoma with a long vascular
stolon, although it is not as long as in the present
species.

The regular arrangement ol vooids, without
cirewar systems. resembles that of the stalked
species Audistoma globosum and kB. elongatum
and a few sandy species (£. constrictum asp, and
LE. microlarvum t.sp.).

This large, fleshy colony, with its characteris-
tically eudistomid zooids and long, delicate
vascular stolon, is readily distinguished from other
species of the genus.

The colony trom Port Hedland recorded above
is long and rope-like, and although its zoaids seem
to be the same as the type material, they are badly
mutilated and the identification needs
confirmation,

Eudistoma tigeum n.sp.
(Fiz. 90)
Eudistoma rigida: Rott, 981, p. 151,

LSP REBI LON

Tyrer Locat ity, Queensland (Heron [., rubble fauna,
coll. P.Kott, August 1975, holotype OM GI 1941: Wistari
Reef, low water mark, rubble zone, coll. P Kort August
1975, paratvpes QM G11942 4; Wistari Reet, coll,
P Kott 6.8.82, paratype QM GH 1362.

Fortier Recoros; Western Australia (Honuiman's
Abrolhos. QM GH2135, WAM 839.83). Queensland
(Hervey Bay, QM GH4559-460; Capricorn Group, QM
G11993 GHI354 GH1362 GH4518-9). Fis (Rott 1981).
Drscriprion

EXTERNAL ApprarAncr- Firm, gelatinous
colonies are circular, oval or slightly irregular
cushions or sheets, up to Sem long and from 0.5
to [Sem thick, with a smooth, sand-lree surface.
They are fixed by the whole of the basal surface.

In hfe more or less circular patches of black
or ‘gallstone-yellow’ (Ridgeway 1886) pigment are
in the surface test. These patches, up to about
Q.5em in diameter, are separated by broad (about
2 tu 3mm wide) areas of grey or White test. In
preservative the whitish ureas hecome reddish-

231

brown, rust coloured or brownish-yellow, the
pigment contained in spherical pigment cells 0.02
to 003mm in diameter. The darker pigment,
contained in regularly shaped cells. fades i
preservative and the patches thal were darkly
pigmented in life become translucent. The colour
pattern is confined to the surface test, and the
remainder of the test is cloudy and translucent.
A little sand is embedded in the basal test. bul
absent clsewherce. Faceal pellets are in the test.

Zooids are in circular systems of 5 or 6 zooids,
The systems are independent of the pigment
patches, and are about 2mm in diameter. In frestily
preserved zootds the stomach and the proximal
part of the intestine ure green.

InvoRN at Structure Zooids are robust, but
only about 4mm when contracted, and up to 8mm
when extended. Strong circular muscles surround
each siphon, Theatrial siphon is often long, about
3 times the length of the branchial siphon. About
20 longitudinal muscles are on the thorax,
extending onto the adbomen in 2 or more bands,
The inner layer of circular muscles on the thorax
is thin, but forms an almost continuous coat of
atleast 25 bands. Branchial tentacles are in 3 circles
of about 12 or more. Only a fairly shallow
unpertorated area of pharynx is anterior to the
stigmata. Stigmata are [8 in the posterior row,
22 in the next row, and about 24 in the anterior
row (Which inclines forwards along cach side of
the mid-dorsal ling),

There is the usual small smooth-walled stomacti
in the posterior end of theabdomen. A longalmost
elliptical posterior Stomach is in the posterior end
of the descending limb of the gut loop. Long
tubules of the gastric gland extend anteriorly along
the ascending limb of the gut loop, level with the
duodenal area. and a mass of yesicles surrounds
the duodenal area.

One or 2 relatively large embryos are in the
atrial cavity of Specimens collected in March (QM
G11943), but not in July or August. The larval
trunk is 0.75mm long, and the broad tail curves
up across the lett side of the anteriot end of the
trunk at the buse of the ampullae, and then
continues posteriorly along the mid-dorsal line,
reaching (0 about three quarters ol the distance
slong the dorsal border. Large median ectodermal
ampullae alternate with the 3 stalked adhesive
organs in the anterior mid-line. The stalks of the
adhesive organs are thin, bul not long, and there
is w circular knob of adhesive cells in a shallow
epidermal cup.

Rimanks: The pigment pattern in this species
resembles that of E maculosum nap. which is
distinguished by its larger larva with bract-like

232

MEMOIRS OF THE QUEENSLAND MUSEUM

Fig 90, Eudistoma tigrum, n.sp. a, colony (QM G11943); b, arrangement of zooids. showing circles of small
atrial openings in the centre of irregular cireles of the larger branchial openings (QM GH1354); e,d, zooids,
showing Various positions of atrial siphon (QM G11942 GH1354); e. larva (QM G1I1943). Seales; a. tem:

b, 2mm; ¢,d, 0.5mm: e, 0.2mm,

ectodermal ampullae that embrace the base of each
adhesive organ and the long, enlarged platforms
of adhesive cells. The pigment pattern is less
conspicuous in preseryed material, although large
dark pigment cells and smaller tan ones persist
for a long time in preservative. ELyedistome
muscosum nom. noy. has a regular cushion-like
colony, brownish-red zooids with a large spherical
mass of male follicles, spherical brown-red
pigment cells (0.03 to 0.04mm in diameter) and
a larger larva (trunk Imm long) than the present
species. Eudistoma purpureum n.sp., also has
rounded cushion-like colonies rather than the
more extensive sheets of the present species, a dark
vas deferens, and its larvae (trunk 1.5mm long)
are larger than those of the present species.

Larvae, with their broad tails curving around
on the left side of the larval trunk, resemble those
ol &. vilhoeviride, although the ampullae are
different.

Colonies, zooids and Jarvae of specimens from
Fiji assigned to F. rigida by Kott (1981) are
identical with the present species, Specimens from
French Polynesia provisionally assigned to FE.

rigidum by Monniot. and Monniot. (1987) have
smaller colonies and smaller larvae (less than
0.5mm) and do not appear to be the same as the
Fijian or Australian material,

Eudistoma tumidum n.sp.
(Fig. 91)
Eudistome ovatiunn Kolt, 1972e, p. 43 (part, specimen
from St. 27).

DisTRIBUTION

Typr Loeariry; Gull of Carpentaria. 16°52.7’S,
140°56.2'E, Station 27 CSIRO Prawn Suryey, 5.8.1963,
holotype, AM Y 1068,
DESCRIPTION

ExrerNnAL ApprarANce: The single colony
available is more or less dome-shaped, about 6cm
in diameter, consisting of a number of lobes of
one to 2cm diameter arising from a commion basal
test mass. Although the preserved specimen is
distorted and hardened and the rounded lobes of
the upper surface are flattened, in lite they
probably were rounded and when inflated the
colony probably appeared as an entire hemispher-

THE AUSTRALIAN ASCIDIACEA 2

ical mass, its separation into discrete lobes
becoming obscured. The preserved specimen is
grey and colourless, without sand, either on the
surface or embedded on the test. However, the
centre of each lobe, and of the colony, is packed
with faecal pellets. Zooids are crowded and open
all around the surface of the lobes. The arran-
gement of zooids could not be determined in this
distorted specimen. However, the long atrial
siphon suggests that they are arranged in circles
with the atrial apertures in the centre of each circle.

INTERNAL StRuctTuRE: Zooids are robust.
Contracted thoraces are only about Imm long but
they are also relatively thick. About 20 longitud-
inal muscle bands on the thorax continue along
the ventral border of the abdomen. On the thorax
the longitudinal bands overlie about 30 distinct
bands of transverse muscle. There are 3 rows of
branchial tentacles, those in the posterior row
being relatively long. The dorsal end of the first
row of stigmata inclines anteriorly along each side
of the dorsal mid-line. There are at least 20
stigmata in the anterior row, but these could not
be counted accurately. The longitudinal muscle
bands continue along each side of the long
abdomen, which has the usual smooth eudistomid
stomach at its posterior end. The male and female
gonads are in their usual position in the posterior
end of the gut loop.

This specimen, collected in August, has up to
4 developing embryos in the peribranchial cavity.
The larval trunk is 0.5mm long, and the tail is
wound almost three-quarters of the way around
it. A large cerebral vesicle has an otolith, and an
ocellus with conspicuous lens cells. Adhesive
organs are relatively small, each with an axial cone
in its epidermal cup at the end of a long, slender
stalk. Each of 4 long, pointed lateral ectodermal
ampullae on each side of the anterior end of the
trunk has a parietal branch from its base. The
parietal branches also come to a point anteriorly
but are rounded posteriorly. There are no median
ampullae.

Remarks: The species is characterised by its
naked, lobed colony with the zooids in circles,
and by its larvae with parietal lobes at the base
of the exclusively lateral ampullae.

Eudistoma laysani also has naked, lobed
colonies with crowded zooids, but the lobes are
smaller, zooids are not in systems, and both zooids
and larvae are smaller than those of the present
species. Eudistoma gilboviride also has lobed
colonies and separate transverse muscle bands
rather than a continuous coat. However, the lobes
of £. gilboviride are top-shaped, its pigmentation
is conspicuous and persists for a long time in

233

Fic. 91, Eudistoma tumidum n.sp. (holotype AM
Y 1068): a, colony; b, thorax showing muscles; ¢, larva.
Scales: a, lem; b,c, 0.1mm.

alcohol, its zooids are not crowded, and larvae
are much larger than those of the present species
and lack the parietal lobes at the base of the lateral
ampullae.

Although both zooids and larvae are similar,
Kott (1972e) was in error in assigning this specimen
to E. ovatum. The latter species has extensive,
smooth-surfaced colonies without lobes, and with
embedded sand. Its larvae differ in that, although
there are 2 lateral ampullae with parietal branches
on each side, the dorsal and ventral ampullae are
median (albeit with a parietal branch on each side)
and the tail is slightly shorter than that of the
present species.

The lectotype (ZMA TU1268) of Eudistoma
segmentatum (Sluiter, 1909) also has the centre
of each lobe of the colony packed with faecal
pellets. However, zooids open at the free ends of
long cylindrical stalks (rather than around convex
sessile lobes arising from the common basal test,
the thoracic transverse musculature is in a
continuous coat (rather than in separate bands
forming an open mesh with the longitudinal
muscles), and both atrial and branchial siphons
are short (in the present species the atrial siphon
is long).

Genus Exostoma n.gen.
Type species: Polycitor ianthinus Sluiter. 1909,

The genus is monotypic. It has 6-lobed branchial
and atrial apertures, on well developed muscular
siphons. The atrial siphon is posteriorly positi-
oned, and opens into an extensive cloacal cavity.
Longitudinal muscle bands extend from the thorax

234

along the abdomen in a band cach side of the
ventral line. A conspicuous layer of transverse
thoracic muscles lies beneath the longitudinal
bands. There are 3 rows of stigmata without
parastizmatic vessels. The oesophageal neck is
Jong, and the smooth stomach is in the posterior
part of the long abdomen. Only short vascular
processes arise from the posterior end of the
ubdoren,

Although Sluiter (1909) did not record the
presence of a cloacal chamber in his description
of Polvettor tanthinus, bis figure (pl. VII, fig.
3) clearly shows the aperture at the top of the
colony,

In its extensive cloacal cayity, posteriorly
positioned 6-lobed atrial siphon, and 3 rows of
stigmata the genus resembles species in //ypodis-
toma. However, zooids of the new genus are
characteristic of the Polycitoridae rather than the
Holozoidae, being long. with a Jong oesophageal
neck, short vascular processes, and brooding their
embryos in the atrial cavity (rather than ina brood
pouch), The 3 larval adhesive organs ure in the
median line and have a wide flat-topped tuft of
axial columnar cells in a deep epidermal cup, as
in Euelistoma.

The genus Hypodistoma Tokioka, 1967a,
defined by its type species Distoma deerratunr
Sluiter, 1895 from northern Australia. is a genus
of the Holozoidae (related to Sigillina) which
includes 7, vasta (Millar, 1962) from South
Africa. However. Hypodistoma vastum: Tokioka.
1967a from the Palau ty is a junior synonym of
Polveitar ianthinus the type species of the
present new genus, Axvsfonta.

It seems the presence of a cloacal cavity, a
unique feature in the Polycitoridac, is a devel-
opment in parallel with the development ol a
similar colony form in the Holovoidae, and the
similar position of the atrial siphon is a convergent
adaptation associated with the presence of the
extensive cloacal cavity. Phylogenetically, the new
genus, appears most closely related to Audistomt,
with its long oesophageal neck, 3 rows of stizmata
and conspicuous transverse thoracic muscle bands
beneath the longitudinal bands,

The only known species has a tropical western
Pacific range.

Exostoma ianthinum (Sluiter 1909)
(Fi, 92)
Polyetror lanthinus Stuiter, 1909, p, 20, Van Name 1918,
p. 135,
Hypodisroma jantinum: Millar, 1975, p. 207,
Y Polyettor terasus Shuiter, 1909 p. 18,

MEMOIRS OF THE QUEENSLAND MUSEUM

Hypudistama vasiunn Tokiokw, 19674, p, U6, ¢

Nishikawa, 1984, p, (21.
Not Sivilling vasta Millay, 1962, p. (53,

DistRIntiTiON

New Recorus, New Gumea (Motupore |. QM
GH235). Philippines (QM GH495).
Previousty Recoroen Indonesia (Sharer 1909,

Millar 1975). Philippines (Yaa Name 1918). Palau Is
(Tokioka 1967a).

The species has not yet been recorded from Australia.
although its occurrence off Port Moresby is not far
removed from the north caster Australian continental
shelf and probably it occurs. there. It was Laken in sea
grass beds at Motupore I. and has been recorded down
to [50m (Van Name 1918),

Description

ExternaL Appearance, The colony. varies
from an irregular cushion up ta 3cm thick, fixed
by a large part of its base, and with 3 or 4 large
common cloacal openings on the upper surface,
to an upright cone with a single large terminal
cloacal aperture. The test is firm, although the
outer layer is separated from the inner core by
the extensive interconnecting cloacal spaces that
are 2 to 3mm below the surface, The surface of
the colony has wide rounded ridges and swellings
that are generally oriented along radii that
converge toward the cloacal apertures, ‘lhe
branchial apertures of the zooids open in the
depressions between these ridges and swellings,
In preservative colonies are always a dark
purplishebrown colour

INTERNAL StRucTURE; Contracted zooids are
ahout [cm long, the greater part of their length
being the long polycitorid oesophageal neck. The
6-lobed branchial aperture is terminal. There is
a relatively long atrial siphon from the postero-
dorsal corner of the thorax, and in relaxed zooids
itis directed postenorly. Although in contracted
vooids it is often found directed anteriorly, this
could result from the contraction of the zoids
und their withdrawal from the surface of the
colony, Zooids are in crowded groups curving
across the top and around the sides of the cloacal
spaces beneath the surface of the colony. Their
6-lobed atrial apertures on the end of the long
siphons open into the roof or outer wall of the
cloacal cavities.

he body musculature consists of numerous,
but fine. longitudinal and transverse bands.
Longitudinal museles extend down the branchial
siphon in 6 groups, one corresponding to each
lobe around the rim of the aperture, About 20
Jongitudinal bands are on each side of the thorax.
These continue as a pair of wide bands along the
length of the abdomen, one each side of the mid-

THE AUSTRALIAN ASCIDIACEA 2 235

ventral line. Sphincters surround each of the
apertures and the anterior part of the pharynx
in front of the perforated area. About 30 circular
muscles are fairly evenly spaced along the whole
length of the thorax, Other circular and longi-
tudinal bands extend along the whole length of
the long atrial siphon.

At the base of the branchial siphon are 3
particularly robust tentacles, one on each side and
one in the mid-ventral line. These alternate with
2 smaller tentacles in a circle slightly anterior to
the larger ones. Rudimentary tentacles alternate
with the larger sizes. The opening of the neural

duct is directed forwards. The pointed dorsal
languets are found slightly to the left of the dorsal
mid-line, An extensive unperforated part of the
pharyngeal wall exists anterior, and another
posterior, to the perforated area which has 3 rows,
each of 20 long stigmata,

The oesophagus is long, the smooth shield-
shaped stomach is in the posterior end of the
abdomen, The duodenal area is fairly long, and
is sharply constricted from an oval posterior
stomach. The narrow mid-intestine curves around
in the pole of the gut loop. It enters the rectum
at the proximal end of the descending limb, There

Fic. 92, Exostoma janthinum o.gen. (QM GH235): a, colony; b, section through colony showing branchial openings
of zooids into surface depressions, and long atrial siphons opening into cloacal canals; ¢, thorax; d, abdomen;

e, larva. Scales: a, |m; b, 2mm; c,d, 0.5mm; e. 0.2mm.

236

is a branched gastro-intestinal gland, but no
reservoir,

The male gonad consists of a clump of almost
spherical follicles on the right side of the gut loop
in the vicinity of the stomach. A group of up to
3 large eggs are on the outside of the male follicles.
A single ovum is incubated in the right peribran-
chial cavity anterior to the atrial siphon. Embryos
are in the atrial cavity of the New Guinea specimen
(collected in November). In the Philippine
specimen, collected in July, tailed larvae are
present. The larval trunk is 0.8mm long and the
tail relatively short, being wound only half-way
around the trunk. The 3 large adhesive organs,
on short, thick stalks, are in the median line and
alternate with paired ectodermal ampullae. The
oozooid has 2 rows of stigmata.

Only short, inconspicuous vascular appendages
are at the posterior end of each zooid.

Remarks: Although the colony and to some
extent zooids of this species resemble those of
Hypodistoma, the zooids differ in having a long
oesophageal neck, a small eudistomid-shaped
stomach, and short, inconspicuous vascular
appendage; and lacking a stalked brood pouch.
Zooids are characteristic of the Polycitoridae. The
species differs from Eudistoma spp. in having
extensive cloacal systems.

Further, larvae resemble those of certain
Eudistoma spp. (see E. maculosum n.sp.) with
large adhesive organs on short, thick stalks.

Hypodistoma vastum: Nishikawa, 1984 from
the western Pacific may be a synonym of the
present species. Nishikawa (1984) believed it to
be conspecific with H. vastum: Tokioka, 1967b,
and with H. ianthinum: Millar, 1975, which are
bothsynonyms of Exostoma ianthinum. However,
he also included Hypodistoma vastum (Millar,
1962) in his synonymy. Since the latter species
is a member of a different family and genus, its
inclusion amongst the synonyms of Nishikawa’s
specimen raises doubts as to the identify of that
specimen.

Polycitor torosus Sluiter, 1909, appears a
cushion-like specimen of the present species.
Although Sluiter regarded the gut loop as
relatively short, this was probably only apparent,
owing to the contraction of the abdomen, for
relaxed zooids are reported about the same length
as those of the present species.

Genus Brevicollus n.gen.
Type species: Brevicollus tuwheratus n.gen. n.sp.

The genus is characterised by its relatively short,
embedded zooids with separately opening 6-lobed

MEMOIRS OF THE QUEENSLAND MUSEUM

apertures, 5 rows of stigmata, each row crossed
by a parastigmatic vessel, and a short oesophageal
neck. The stomach wall has longitudinal folds.
Gonads, present in the end of the gut loop, consist
of relatively large and numerous pyriform male
follicles and a 5- or 6-egg ovary. Numerous (up
to 12) embryos are brooded in the atrial cavity.
The proximal part of the oviduct runs a convoluted
course over the surface of the ovary. The body
musculature consists of longitudinal bands that
exchange fibres with one another to form a
meshwork oyer the sides of the thorax before
extending down the length of the abdomen. There
are no transverse or oblique muscles.

The 3 deep, tulip-shaped, sessile larval adhesive
organs in the anterior mid-line of the trunk are
unique. These are surrounded by numerous
ectodermal ampullae that project from the anterior
end of the trunk. Also fine thread-like extensions
from the ectodermal cells expand into tear-shaped
vesicles at the surface of the test as in species of
Sigillina, Polycitor and Eudistoma (see Annotated
Glossary: larvae).

Polydistoma, a new genus of the Holozoidae
also with 5 rows of stigmata, is distinguished from
Brevicallus by its holozoid vascular stolon and
brood pouch. The two known species of Poly-
distoma lack parastigmatic vessels, although these
are in other holozoid genera (Distaplia, Hypsis-
tozoa and Neodistoma). In view of other differ-
ences, the presence of parastigmatic vessels in
Brevicollus rather than being indicative of
common ancestry with the Holozoidae, probably
is due to convergence, as there is no other evidence
of any phylogenetic relationship.

Brevicollus has been assigned to the Polycito-
ridae because of its short vascular appendages,
separately opening zooids, and absence of a
posterior abdomen with gonads. However, it has
some characters that are not shared with poly-
citorids, viz. a relatively large thorax, parastig-
matic vessels in the branchial sac, a short
oesophageal neck and a large number of embryos.
Further, although the larval adhesive organs are
in the anterior mid-line these sessile, tulip-shaped
organs are unique. It is possible these anomalous
characters are secondary adaptations that would
not preclude a relationship with the Polycitoridae.
The convolutions of the vas deferens could be
associated with a secondary shortening of the
abdomen. Another alternative for Brevicollus is
an affinity with euherdmaniinid genera, since it
differs from Ritterella only in its larva, convoluted
vas deferens and lack of a posterior abdomen
containing the gonads.

Thus, although, at present the genus is classified

THE AUSTRALIAN ASCIDIACEA 2

in the Polycitoridae on the basis of separately
opening apertures, and Jack of a posterior
abdomen and long vascular stolon, tt is possible
the phylogeny of this new genus would be more
accurately represented by an independent status
reflecting a relationship with Ritterella.

This monotypic genus is at present known only
from 2 specimens, one from each of two locations
in southern Australia.

Brevicollus tuberatus n.sp.
(Fig. 93. Plate L6h)

Distr ne tion

Tyre Locaciry: South Australia (Che Gap, 15 20m,
coll. N. Holmes and §. Shepherd 9.4.87, holotype SAM
E2059 OAS GH4IS88). Victoria (Gabo 1., 10 15m, coll.
J, Watson 14,5,70, paratype MV F45284 OM GH4952).
FurRTHER Reeorps None.

DESCRIPTION

Exvernat Appearance: The holotype colony
is firm and tuber-like, growing along a weed stalk.
The colony is basically a thick, undulating
cylinder, randomly constricted along its length to
partially separate it into short potato-shaped

237

masses [rom 2 to Sem long and about 2em in
diameter. The more angular lobes (4) of the
paratype colony articulate with one anather along
the stalk of a Pyuwra.ausiralis, A thin layer of sand
iy on the surface, and also scattered evenly, but
sparsely, through the firm, gelatinous, internal
test. Zooids open all around the surface of the
colony and converge toward the centre.
INTERNAL Strucrure: Zooids are relatively
large, about lem long with a wide thorax. Both
6-lobed apertures ure on the anterior end. Thorax
and abdomen each oceupy about half the length
of the zooid. Strong circular muscles surround
each aperture, Siphons are short. Longitudinal
muscle bands from each siphon radiate out onto
the thorax where they exchange libres with one
another to form a meshwork. They continue on
to the abdomen ag fine bands along its length.
Five rows of 35 long rectangular stigmuta are on
each side of the branchial sac, Each row ts crossed
by 4 parastigmatic vessel; und is interrupted in
the dorsal mid-line by the large dorsal sinus.
Transverse branchial vessels continue over the
dorsal sinus where each is produced into a narrow,

Pic. 93. Brevicellus tuberatus, n.geo., n.sp. (holowpe SAM E2059, QM GI14188): a. colony; b. void: e, larva.
epidermal vesicles not shown; d. anterior end of larval triink, test removed from all but a small section. taking
vesicles with it, to expose one of the unusual adhesive organs surrounded by epidermal ampullac. Scales:

a. lem: b, Imm, ed, Imm.

238

pointed, dorsal languet. Smaller languets occur
Where the parastigmatic vessels cross the dorsal
sinus.

The oesophagus is relatively short. The rather
small, shield-shaped stomach is in the middle one-
third of the abdomen. It has & broad, rounded,
longitudinal folds in its wall. A long elliptical
posterior stomach is in the posterior third of the
descending limb of the gut loop. The wide rectum
extends from the pole of the gul loop to about
halfway up the thorax, terminating in a 2-lipped
anus. Gonads are in the posterior end of the gut
loop overlapping the pole of the loop on the right
side. The testis consists of about 25 pyriform
follicles and the ovary contains up to 4 eggs, one
or two larger than the others. The proximal end
of the male duct runs a complex, convoluted
course as it leaves the testis, sometimes becoming
intermingled with the male follicles, then curving
around onto the outer surface of the ovary before
it straightens out to run alongside the rectum. It
opens in the atrial cavity near the anus.

In this colony about |2 large, orange embryos
are at various stages of development in the right
peribranchial cavity. The trunk of the tailed larva
is about Imm long and is deeper than long. The
oozogid is vertical, with a well formed branchial
sac and gut loop. The former has 2 rows of
stigmata. The atrial aperture is directed horizon-
tally at right angles to the branchial aperture
(unlike Eudistoma spp.). There is a large otolith
and ocellus and the tail is wound completely

MEMOIRS OF THE QUEENSLAND MUSEUM

around the trunk, The almost sessile adhesive
organs are in a vertical line down the centre of
the anterior end of the trunk. They consist of a
deep tulip shaped cup with filamentous lamellae
in the concavity. Numerous, crowded ectodermal
ampullae project from the anterior larval epider-
mis. These, together with masses of tear-drop-
shaped terminal vesicles attached to thread-like
extensions of the ectodermal cells of the ampulla,
obscure the adhesive organs. The whole front and
ventral mid-line of the trunk has a foamy
appearance resulting from these ampullae and
their vesicles.

Remarks; The larval adhesive organs of this
species are in a vertical line, as in Eudistoma and
Polycitor, but they are different, lacking the
central axial cells. Further, the ectodermal
ampullae are unusual, more numerous and
crowded than in other species of the Palycitoridae.
Although the ectodermal vesicles do occur in
Eudistoma spp., they are not unique to the
Polycitoridae, but occur in most other laxa (see
Annotated Glossary: larvae) and are not indicative
olf relationships. These factors, together with the
presence of parastigmatic vessels, a convoluted vas
deferens, and the large number of larvae being
incubated, distinguish the genus and the species
fram others in this family.

Polyeitor obeliseus, also from South Australian
waters, has 6 rows of stigmata. However it has
other characters, in addition to the generic ones,
which distinguish it from the present species.

THE AUSTRALIAN ASCIDIACEA 2 239

PxaTe |: a, Ciona intestinalis (Port Phillip Bay, Vic.). b,c, Rhopalaea crassa, (Heron 1., Qld, thoraces only
visible, abdomina buried in rubble substrate, rectum, terminating in yellow anus, alongside white vas deferens,
yellow ocelli around the border of each aperture, stigmata and muscles clearly seen through the transparent
test and body wall — b, right side; c, dorsum). d, Pseudodiazona claviformis (SAM E1035 Seacliffe SA).
e,f, Clavelina arafurensis (QM G1!1988 Exmouth Gulf, WA).

Photos: a G. Russ; b R. and V. Taylor; d N. Holmes; c,e,f N. Coleman.

240 MEMOIRS OF THE QUEENSLAND MUSEUM

=

PLATE 2: a,b,2c, Clavelina australis (a, Port Hacking, NSW; b, Port Stephens, NSW; c, this Great Barrier Reef
specimen looks like C. australis but the species has not been taken from waters north of Moreton Bay. d,

Clavelina baudinensis (Rottnest L., W.A.). e,f, Clavelina cylindrica (e, QM G9482 Sorrento, WA; f, WAM
758.83 Carnac I., WA).

Photos: a,e,f N. Coleman; b P. Fredrickson; ¢ R. and V. Taylor; d R. Lethbridge.

THE AUSTRALIAN ASCIDIACEA 2 241

Ae 2 = - ’ _

PLATE 3: a, Clavelina dagysa (QM G9485 Dunsborough, WA, the atrial opening, exposed to the camera and
directed upwards, the branchial siphon on the right, curving ventrally to direct the opening downwards). b-
d, Clavelina meridionalis (b, Port Stephens NSW, the branchial siphon on the right of the picture directs
the aperture downwards and the atrial aperture, a short distance down the dorsal surface, faces up; c, QM
G10140 Port Stephens, NSW; d, Port Stephens, NSW). e-h, Clavelina moluccensis (e, Marion Reef, Coral
Sea; f, Adelaide, SA; g, South Australia, branchial apertures exposed directly to the camera showing branchial
tentacles radially arranged inside each incurrent canal; h, QM G11996 Kangaroo I., SA, the outsides of the
branchial sacs inside the atrial cavities seen through the atrial apertures).

Photos: a-c,e,h N. Coleman; d P. Fredrickson; f N. Holmes; g R. Kuiter.

242 MEMOIRS OF THE QUEENSLAND MUSEUM

tl

ae

ms

Pate 4: a, Clavelina nigra n.sp. (QM G9486 Rottnest I., WA). b, Clavelina oliva n.sp. (QM GH4108 Lizard
I, Qld). ¢, Clavelina ostrearium (South Australia). d,e,2f, Clavelina pseudobaudinensis (showing variations
in the extent of pigment patches — d, QM G10091 Jervis Bay, NSW; e; QM G9484 Portsea, Vic.; 2f, Lord
Howe I.). g, ?Clavelina robusta n.sp. (Port Hedland, WA).

Photos: a,e-g N. Coleman; b D. Parry; c R. Kuiter; d P. Fredrickson.

THE AUSTRALIAN ASCIDIACEA 2 243

PLaTE 5: a-c, Nephtheis fascicularis (a, QM GH2093 Martha Ridgeway Reef, Qld; b, QM G9258 Roebuck Bay,
WA; c, Port Hedland, WA). d, Pycnoclavella arenosa n.sp., (QM GH4360 Erith I., Bass Strait, with yellow
thoraces projecting through the white sand on the common stalk). e, Pycnociavella aurantia n.sp. (QM GH2295
Nuyts Archipelago, SA). f, Pycnoclavella detorta (QM G9488 Wistari Reef, Qld).

Photos: a E. Lovell; b,c,e,f N. Coleman; d N. Holmes.

244 MEMOIRS OF THE QUEENSLAND MUSEUM

a Oe.
= af,

=e

Piate 6: a-f, Pycnoclavella diminuta (showing colour variants — a, QM GH1302 in caves Ward I., SA; b,
Port Hedland, WA; c, Carnac I., WA; d, QM GH4083 Exmouth, W.A.; e, Lord Howe I.; f, QM G10162
Lizard 1., Qld). g, Pycnoclavella elongata n.sp. (SAM E1981 Franklin I.,-SA). h, Pycnoclavella tabella n.sp.
(Portsea, Vic.).

Photos: a R. Kuiter; b-f,h N. Coleman; g N. Holmes.

THE AUSTRALIAN ASCIDIACEA 2 245

Piate 7: a-c, Euclavella claviformis n.gen. (a, QM GI0I52 Port Stephens, NSW; b, Port Stephens NSW; c,
Botany Bay, NSW). d,e, Sigillina australis (d, QM GH944 Great Australian Bight, SA; e, Sorrento, WA).
f-g, Sigillina cyanea (f, ? NE Qld; g, QM G9479 Rottnest I., WA).

Photos: a,e,g N. Coleman; b P. Fredrickson; c,d R. Kuiter; f E. Lovell.

246 MEMOIRS OF THE QUEENSLAND MUSEUM

(QM GH1305 Topgallant I., SA). ¢,d, Sigillina signifera (c, Lizard 1., Qld; d, QM GH278 Britomart Reef,
Qld). e, Hypodistoma deerratum (QM G10153 Lizard L., Qld). f-h, Hypodistoma mirabile (f, Golden I., SA;
g, Perforated I., SA; h, QM GH2379 Ward I., SA).

Photos: a,b S. Shepherd; ¢ D. Parry; d E. Lovell; e N. Coleman; f,g W.H. Sasse; h N. Holmes.

THE AUSTRALIAN ASCIDIACEA 2 247

Prate 9: a, Distaplia australiensis (South Australia). b, Distaplia dubia (QM GH52 Lord Howe 1.). ¢,d, Distaplia
florida n.sp. (QM GH4103 Byron Bay, NSW — ¢, colony relaxed; d, colony contracted). e, Distaplia pallida
n.sp. (colonies on experimental fouling plate QM G11924 Portsea Pier, Vic.)-f,g, Distaplia stylifera (f, Fremantle
WA; g, QM GH2407 Hotspot, SA),

Photos: a,g N. Holmes; b-d,f N, Coleman; e G. Russ.

248 MEMOIRS OF THE QUEENSLAND MUSEUM

SRY hee, erm
igs

Me a

Piate 10: a-c, Distaplia viridis (a,b, QM GH45 Portland, Vic.; e, QM GH4159 Golden I., SA), d-h, Hypsistozoa
distomoides, showing colour variants (d,e, Flinders I., SA; f, QM GH1280 Ward I., SA; g, QM GH2390
Hotspot, SA; h, QM GH1297 Ward I., SA).

Photos: a,b N. Coleman; c,d,g N. Holmes; e,f,h, R. Kuiter.

THE AUSTRALIAN ASCIDIACEA 2 249

Pate 11: a,b, Neodistoma mammillatum n.gen. n.sp. (SAM E1984 Seacliffe, SA). c-h, Sycozoa cerebriformis
(colour variants — ¢, QM GH2394 Flinders 1., SA; d, Jervis Bay, NSW; e, QM GH2393 Flinders I., SA;
f, QM GH2284 Nuyts Archipelago, SA; g, detail of colony Port Hacking, NSW; h, well developed colony,
South Australia).

Photos: a-c,e,f N. Holmes; d P. Fredrickson; g N. Coleman; h R. Kuiter.

250 MEMOIRS OF THE QUEENSLAND MUSEUM

ia

i
ae
a ry

7
ie

PLaTE 12. a, Sycozoa murrayi (QM GH4155 the Gap, SA). b, Sycozoa pedunculata (South Australia). e,d, Sycozoa
pulchra (South Australia). e, Sycozoa sigillinoides (QM G10148 St. Helens, Tas.). f, Stomozoa australiensis

n.sp. (QM GH2392 Ward I., SA). g, Stomozoa bellissima n.sp. (QM G9267 Exmouth Gulf, WA).
Photos: a W.H. Sasse; b,c R. Kuiter; d N. Holmes; e,g N. Coleman; f S.A. Shepherd,

THE AUSTRALIAN ASCIDIACEA 2 251

PiaTe 13. a,b, Polycitor calamus n.sp. (a, QM GH4188 Avoid Bay, SA; b, SAM E2057 Flinders I., SA). ¢,
Polycitor cerasus n.sp. (SAM E2080 Nuyts Archipelago, SA). d-h, Polycitor giganteus (d, Port Noarlunga,
SA; e, Port Stephens, NSW; f, Bass Strait; g, South Australia; h, Botany Bay, NSW). i, Polycitor nubilus
n.sp. (SAM E2079 Flinders I., SA).

Photos: a W.H. Sasse; b,c,i N. Holmes; d,f,h N. Coleman; e P. Fredrickson; g R. Kuiter.

252 MEMOIRS OF THE QUEENSLAND MUSEUM

Piate 14. a-d, Cystodytes dellachiajei (a, QM GH2401 West I., SA; b, QM GH2402 West I., SA; c, South
Australia; d, New South Wales). e, Polycitorella coronaria (QM GH2377 Hotspot, SA). f,g, Polycitorella orientalis
n.sp. (f, QM G9477 Swain Reefs, Qld, contracted specimens, with conspicuous rudimentary cloacal cavities
opening to the surface; g, Heron I., Qld, extended specimens, the branchial openings conspicuous and’ the
atrial apertures in the shaded cloacal depressions in the centre of each system),

Photos: a,b S. A. Shepherd; c R. Kuiter; d,g P. Fredrickson; e N. Holmes; f N. Coleman.

THE AUSTRALIAN ASCIDIACEA 2 253

Pate !5: a, Eudistoma amplum (Heron 1., Qld, with green Prochloron on surface). b, Eudistoma constrictum
n.sp. (QM GH229! Topgallant I., SA). ¢, Eudistoma elongatum (Moreton Bay, Qld). d-f, Eudistoma gilboviride
(d, crowded lobes, OM G1I1959 Lizard I., Qld; ef, QM G11961 Swain Reefs, Qld).

Photos: a D. Parry; b N. Holmes; e~f N. Coleman.

254 MEMOIRS OF THE QUEENSLAND MUSEUM

Photos: a,b N. Holmes; c N. Coleman; d R. Kuiter; e,f D. Parry; g S.A. Shepherd; h W.H. Sasse.

THE AUSTRALIAN ASCIDIACEA 2

LITERATURE CITED

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and Pistaplia sniirht two new colonial ascidians
from the west coast of North America. Bull. sth
Calif. Acad. Sei. 67(3): 143 54.

Acassiz, J.L.R. 1850, On the embryology of Asvidia
and the characteristics of mew species fram the
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59,

Avoer, J. 1863. Observations on the British Tunicata
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Atppr, J. AND Hancock, A, 1907. British Tunicata.
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Arnndcae A. CHrisri-Linpr 1926, Contributions to
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1927, The genus Tlohranchion Herdm., with supple-
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Ark, Zool. Stackholm 18(35); | 20.

1934. Northern and Arctic invertebrates in the
collection of the Swedish State Museum. 1X
Tunicata. Part 4, Agnesiidae, Rhodosomatidae,
Ascidiidae, Cionidag, A. svenska Wetensk-Akad,
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1950. Ascidiacea Part 2, Further cool. Resulis Swed.
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Hineprn, E. VAN 1887. Les genres Ecreinasetdia Herd.
Rhopalaea Phil, et Stuiteria ng. Note pour servir
& la classification des Tuniciers. Bul/, Acad. Belg,
(3)14(7); 19-44,

fiexrpores, BE. van, Ant Sucys-Longeames, M. 1913,
Tumeiers. Caducichordata (Ascidiaces et Thalia-
ces). Réyult. Vovaze 8.Y. Belgica, Zoulugie: | 122.

Berkice, NJ, 1932 Ascidians of the Bermudas. Biel,
Bull. mar. biel. Lab.. Woods Hole 62; 77-88.

19354. Studies in tunicate development IIL. Diller-
ential retardation and acceleration. Phil, Trans. R.
Soc. B 225: 225-326.

1935b. Studies in tunicate development IV. Asexual
reproduction. Phil, Trans. R, Soe, B 225: 327 79.

1936, Studies in tunieate development V. The
evolution and classification of ascidians. Phil.
Trans. R. Sec. B 226: 43-70,

1947a, The structure. tadpole and budding of the
ascidian Pvemoclavella aurilucens Garstang. J. mar.
hiol. Ass. UK, 271): 245-41.

1947b, The structure, development and budding of
the ascidian Eudisrama. J. Morph. 81: 269-¥1.

1948a. Tadpole larvae of the ascidians Polyeiior,
Euherdmania and Pulysyneraton, J. Morph, 82:
355-64.

194Nb. Budding and the reproductive cycle of
Distaplia. OJ. mricrose, Sci, 89: 253 89.

1950. The Tunicata. Ray Suc. Pubiy 133; 1-354.

1955. ‘The Origin of Vertebrates’ (Oxford University
Press: London) 257pp.

Repent, NJ. ano Annorr. D.P. 1999, The structure
of the ascidian Prereclavella stanievi np. und the

nature of its tadpole larva, Com Res. 27 44 9,

CASILE

CAN EPRY

255

Bixyry, W.G, 1870, Mollusca. /n Gould, AAW ‘Report
onthe Invertebrata of Massachusetts’ 2nd. edition,
p, | 27 (Massachusetts Legistature: Bostan).

Bonnrvir, Ko T8986. Ascidiae simplices og Ascidiae
compusiae. In Den Varske Nordhaus-Expedirion
/876-78 (Christianaia) 23. Zoologie (Tumeara 2);
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THE AUSTRALIAN ASCIDIACEA 2

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262 MEMOIRS OF THE QUEENSLAND MUSEUM

INDEX TO TAXA

Page numbers of taxon descriptions and figures

appear in bold

Amaroucium,

anomalum, 79

distomoides, 134
Amphicarpa, 165
Aplidie,

cerebriforme, 143

pedunculatum, 147
Aplidium, 13

lobatum, 179

distomoides, 134

pedunculatum, 147 153

triggiensis, 8
Aplousobranchia, 18-20
Araneum, 21
Archiascidia, 35 67

neapolitana, 67
Archidistoma, 76 162 163

aggregatum, 163

richeri, 73

rubripunctum, 73
Ascidia,

canina, 21

intestinalis, 21

lepadiformis, 35

ocellata, 21

pulchella, 21

tenella, 21
Ascidiidae, 13 21
Atapozoa, 82

deerrata, 106

Jfantasiana, 92

marshi, 87 89

mirabilis, 108
Alopogaster aurantiaca, 159
Atriolum, 10 19 83

Botryllinae, 10

Botrylloides magnicoecus, 10

Brevicallus, 4 14 16 162 163 236
tuberatus, 8 236 237-8 254

Chondrostachys, 35 42
cylindrica, 42
macdonaldi, 42

Ciona, 8 12 13 14 15 16 1&8 19 20 21 22 26 34
antarctica, 21
canina, 21
diaphanaea, 22
fascicularis, 22
gelatinosa, 22
imperfecta, 21
indica, 21 24 26
intestinalis, 20 21-4 239

intestinalis longissima, 2\ 34
intestinalis gelatinosa, 21 34
ocellata, 21
pulchella, 22
robusta, 22
savignyi, 21 24
soctabilis, 21
tenella, 21
Cionidae, 4 9 13 14 18 20-1 24
Clavelina, 16 18 35-8 39 63 66 67 70 79 80 156
arafurensis, 35 36 37 38-9 170 238
australis, 16 35 36 37 39-41 45 50 53 61 63
240
baudinensis, 16 17 33 34 35 36 37 41-2 58 60
61 240
brasiliensis, 16 46
claviformis, 79
coerulaea, 36 51 53
cyclus, 36 54 55
cylindrica, 14 35 36 37 42-5 50 53 63 66 70
240
dagvysa, 12 16 34 35 36 37 45-6 50 57 58 241
detorta, 71
diminuta, 73
elegans, 36 39 48 63
enormis, 36 41 48
fecunda, 16 35 36 37 42 47-8
flava, 38
meridionalis, 12 16 18 33 35 36 37 46 48-50
51 58 241
miniata, 12 18 38 46 50 57
mirabilis, 35 36 37 50-1
minuta, 33
moluccensis, 14 15 16 35 36 37 38 41 44 45
50 51-3 54 61 63 241
nana, 70 71
nigra, 14 35 36 37 53 53-5 242
nodula, 73
obesa, 38 48
oliva, 16 18 35 36 37 38 39 55-7 242
ostrearium, 12 18 33 35 36 37 46 48 50 57-8
242
pseudobaudinensis, 16 33 35 36 37 39 41 42
51 58-61 63 242
robusta, 15 16 35 36 37 41 48 51 53 61-3 242
roseola, 157
sigillaria, 79
viola, 12 36 38 57 63
Clavelinidae, 4 8 9 10 12 13 14 15 16 17 18 19
20 21 24 33-5 63 66 67 81 82 83 84 156 162
Colella,
claviformis, 34 66 79
cyanea, 89
elongata, 205
incerta, 143
murrayi, 146

THE AUSTRALIAN ASCIDIACEA 2 263

pedunculata, 147 153

perrieri, 155

plicata, 143

pulchra, 149

quoyi, 153

ramulosa, 153

sigillinoides, 153

tenuicaulis, 149 152

thompsoni, 64

umbellata, 153
Corellidae, 13
Cyathocormus, 84 137 139

mirabilis, 137
Cystodytes, 8 10 13 15 17 18 69 162 163 178 183

aucklandicus, 179

ceylonensis, 179

cretaceous, 179

dellachiajei, 179-83 252

draschei, 179

durus, 179

fuscus, 182

hapu, 179 183

mucosus, 182 183

perspicuus, 179

Philippinensis, 179 182

punctatus, 182 183

violaceus, 179

violatinctus, 182

Diazona, 24 25
gigantea, 157
vialacea, 25
Diazonidae, 4 6 8 9 12 13 14 15 16 18 19 20 24
24-5 25 31 33 34 66 83 156 162
Didemnidae, 4 78 9 10 12 13 14 15 17 18 19 20
83 109 126
Diplosoma, 16
macdonaldi, 8
multipapillata, 8
Distaplia, 8 10 12 13 14 15 16 17 18 19 81 82 &3
84 109-13 110 126 135 137 156 159 162 178
183 236
australiensis, 110 111 112 113-5 120 121 247
bursata, 114
capensis, 111
cerebriforme, 143
cuscina, 111 112 113 115-6 118 120 122 125
132 133
cylindrica, 126
distomoides, 134
dubia, 111 112 116-8 122 247
durbanensis, 111
fasmeriana, 133
florida, 13 111 112 118-9 120 125 133 247
japonica, 116
magnilarva, 81 127

mikropnoa, 111 127 129
muriella, 110 111 112 119-21
occidentalis, 8 16 110
pallida, 111 112 118 119 121-2 122 124 130
132 133 135 247
prolifera, 111 112 122-4 130 135
racemosa, 111 112 113 120 123 124-5
regina, 111 112 120 123 125
retinaculata, 15 81 82 111 112 125-6 129 133
134 135
skoogi, 111
smithi, 110 114
stylifera, 111 112 114 124 125 127-9 130 132
134 135 247
systematica, 110 113 124
tahihuero, 113 116
tokioka, 111 112 119 122 124 129-30 131 132
vallii, (10 111 113 114 115 116
violetta, 110 111 112 115 121 124 129
130 130-2
viridis, 13 111 112 118 119 121 122 125 126
130 132-3 248
yezoensis, 125
Distoma,
caerulea, 89
deerratum, 105 106 234
dellechiajei, 178 179
laysani, 214
molle, 220
parva, 214
rubrum, 188
Distomidae, 82 83
Distomus, 165
Dumus areniferus, 79

Ecteinascidia
crassa, 26
fusca, 26
solida, 26
Ecteinascidia (? Rhopalopsis) solida, 26
Enterogona, 49 18
Euclavella, 14 19 34 66 67 79
claviformis, 17 66 79-80 86 245
Eucoelium hospitiolum, 183
Eudistoma, 6 8 9 10 13 14 15 16 17 19 69 92 100
101 162 163 178 183 188-94 203 212 222 230
234 236 238
album, 214
amplum, 188 190 192 194-6 222 225 228 253
anaematum, 190 193 196-7 208 218 224
angolanum, 191 192 194 197-9 203 225 228
aureum, 189 193 199-200 226
bulbatum, 163 191 192 193 200-1
caeruleum, 89
carnosum, 16 191 192 198 199 201-3 228
elarum, 15 162

264 MEMOIRS OF THE QUEENSLAND MUSEUM

constrictum, 191 193 203-4 220 229 231 253

cyanea, 89

cyaneum, 89

descideraia, 163

eboreum, 190 193 205 206

elongatum, 15 189 193 204 205-6 210 216 231
253

fantasiana, 92

Jragum, 193

gilboviride, 189 192 194 206-8 232 233 253

glabrum, 193

glaucum, 162 189 193 194 208-10 217 218 224
231

globasum, 189 193 200 204 210-1 218 227 231

gracilum, 191 193 211-2 216

incubitum, 16 162 190 193 194 212-3

laysani, 15 163 189 193 194 204 206 212
214-6 253

loricatum, 193 194

maculosum, 162 190 193 200 210 216-7 225
226 231 236 254

malum, 189 193 196 200 217-8 291

marianense, 209 217 226

microlarvum, 191 193 204 218-20 231

miniacum, 193

molle, 8 220

multiperforatum, 193 228

murrayi, 163

muscosum, 162 190 193 196 198 208 210 217
220-2 224 228 232

olivaceum, 15 162 208 210 214

ovatum, 16 191 192 203 204 222-4 225 229
232 233

parvum, 214 216

pratulum, 190 193 196 208 223 224

purpureum, 16 162 190 193 196 208 217
225-6 232

pyriforme, 191 192 196 199 200 216 222
226-7 229

reginum, 192 198 227 228 254

renieri, 216 226

rigidum, 208 209 231 232

ritteri, 8

rubrum, 194

sabulosum, 191 192 204 222 226 229 254

segmentatum, 149 216 233

snakahri, 198

stellatum, 194

superlatum, 162 170 189 193 210 229-31

tigrum, 190 193 208 210 217 218 222 231-2

toealensis, 193 194 216

tokarae, 194 210

tumidum, 189 192 232-3

viride, 100 101 210

viridis, 100

vitiatum, 196

vulgare, 222
Euherdmania, 6 8 12 13 14 15 17 19 38 53 67
81 &4 86 98 156
clavifarmis, 86
dentatosiphonis, |56
digitata, 156
Euherdmaniinae, 7 9 10 14 15 17 19 30 31 38 79
Exostoma, 8 9 10 13 20 105 106 162 163 194
233-4
ianthinum, 234-6

Halazoa,
cylindrica, 109
valii, 115
Holozoidae, 4.8 9 10 12 13 14 15 16 18 19 20
66 81-4 102 106
Holozoinae, 82 83 162
Homoeodistoma longigona, 33
Hyperiodistoma, 82 162
Hypodistoma, 489 10 13 14 17 81 82 83 84 86
93 100 102 105-6 126 234 236
deerratum, 82 105 106-8 109 194 246
ianthinum, 234 236
mirabile, 82 105 106 108-9 246
vastunt, 15 82 100 LOS 106 108 109 234 236
Hypsistozoa, 8 12 13 14 16 17 18 81 82 84
133-4 135 137 236
dixstomoides, 122 129 133 134-5 248
jJasmeriana, 122 133 135
obscura, 134

Leptobotrylloides dubium, 116
Leptaclinides, 10 83

Molgula, &
Molgulidae, 9 13

Neodistoma, 10 14 18 82.84 135 236
mammillatum, 135-7 249
Nephtheis, 14 19 33 35 60 63 79
faciformis, 64
Sascicularis, 14 55 63-6 243
malayensis, 64
thampsoni, 64

Oxycorynia,
arenosa, 69
fascicularis, 63
pseudobaudinensis, 58

Paessleria, \62
Patridium, 31
pulvinatum, 31 33
Perophoridae, 13
Phallusia intestinalis, 21
Phlebobranchia, 45 89 12 13 14.15 [8 19 20 21

THE AUSTRALIAN ASCIDIACEA 2 265

Pleurogona, 4
Podoclavella, 35
australis, 39 44
cylindrica, 44 51|
dagysa, 45
detorta, 71
fecunda, 47
meridionalis, 48 57 61
moluccensis, 51 53 61 63
ostrearium, 57
polycitorella, 38
procera, 48 50
Polycarpa, §
Polycitor, 8 9 10 13 15 16 25 162 163 165 183
194 236 238
amplus, 194 198 199
angolanus, 197
annulus, 15 17 162 164 165 165-7 170 175
arenaceus, 222
aurantiacus, 159 161
calamus, 164 165 167-8 175 251
cerasus, 164 165 168-9 175 251
circes, 15 17 162 164 165 167 169-70 174
175 177
coalitus, 106 194
crystallinus, 165 177 178
discolor, 194 196
emergens, 164 165 170-1 177
gelatinosa, 169 170 171
giganiteus, 6 164 165 170 171-4 177 178 251
gilboviridis, 206
glaucus, 208
janthinus, 106 194 233 234
irregularis, 214
faysani, 214
longitubis, 104
magalhaensis, 203
mollis, 220
nubilus, 164 165 174-5 251
obeliscus, 164 165 174 175 238
paesslerioides, 197 198 201 203
renziwadat, 25 169
scaber, 222
signifertus, 100 194
subarborensis, 164 165 171 175-7
torosus, 105 234 236
translucidus, 16 171 164 165 170 176 177-8
violaceus, 194
vitreus, 15 162
Polycitor (Eudistoma).
olivaceum, 214
paesslerivides, 201 203
Polycitorella, 4 8 10 13 15 18 162 163 178
183-4 204
coronaria, 183 184-7 188 252
hospitiolis, 183

mariae, 183 184 186 188
orientalis, 183 187-8 252
pallida, 184 186 188
peéresi, \84
setoensis, 184
Polycitoridae, 478 9 10 12 13 14 17 19 20 66
69 81 82 83 106 156 162-3 237
Polycitorinae, 82 83 162
Polyclinidae, 47 8 9 10 12 13 14 15 17 19 20 24
30 38 66 67
Polvelinum, 9 15 24
cylindricum, 42
giganieum, 171
globosum, 171
mikropnous, 129
nigra, 98
Polydistoma, 48 9 10 13 14 81 82 83 84
101-2 105 109 126 236
fungiforme, 101 102-3 105
longitube, 103 104-5
Polyzoinae, 67
Prochloron, 16
Protoholozoa, 84
Protopolyclinum, 9 15 24 30
claviforme, 30 31
pedunculatum, 31
Psammaplidium,
ovatum, 222
pyriforme, 226
Pseudodiazona, 13 14 19 24 25 30-1 33
ahyssa, 31
claviformis, 31-3 238
sabulosa, 30 31
Pseudodistoma, 15 19 231
Pycnoclayella, 7 9 14 15 34 35 38 66 67-9 70 76
79 163
arenosa, 38 67 68 69-71 73 76 243
aurantia, 66 68 69 71 72 73 76 243
aurilucens, 66 67 69 70
detorta, \7 67 68 69 71-3 76 243
diminuta, 67 68 69 71 73-6 77 78 79 244
elongata, 67 68 69 76-7 244
kottae, 66 67 69 73
minuta, 66 69 70
stanleyi, 66 67 69 71
tabella, 67 68 69 73 76 77-9 244
Pycnoclavellidae, 4 6 8 9 10 12 13 1415 17 18
19 20 66-7 69 79 81 83 84 86 98
Pyura, 13
Pyuridae, 9 13

Rhopalaea, 12 13 14 18 24 25-6 28 30
abdominalis, 25 29
birkelandi, 25
crassa, 24 25 26-9 30 238
harimeyeri, 25 29

266

macrothorax, 26 28

neapolitana, 25 26 28 30

nordgaardi, 24 25 26 30

norvegica, 25

piru, 25 26

sagamiana, 26

tenuis, 13 25 26 29-30
Rhopalopsis, 26

birkelandi, 29

crassa, 26

defecta, 25 26 28

fusca, 26 29

neapolitana, 29
Ritterella, 10 13 15 24 236 237

prolifera, 216

Sigillina, 46789 10 13 14 15 16 17 19 81 82 83
84-7 98 100 102 105 108 162 163 203 210 231
234 236
australis, 13 82 84 85 86 87 87-9 90 92 96 101
206 245

caerulea, 89 92

coalita, 106

cyanea, 29 66 85 86 87 89-92 93 96 101 245

deerrata, 106

digitata, 86 87 93 96 99 100

fantasiana, 81 82 84 85 86 87 92-3 99 100 105
162 231 246

grandissima, 12 15 16 81 84 85 86 87 89 93-6
101 170 246

magalhaensis, 198 201 203

mjobergi, 4 8 13 17 19 81 84 85 86 87 96-8

mobiusi, 86 87

nigra, 84 85 86 87 93 98-100 162 231

psammophorus, 86 87

signifera, 85 86 87 89 96 100-1 167 194 210
246

vasta, 234

Sigillina (Paessleria), 201 203

Sigillina (Polycitor), 106

Stereoclavella, 35
australis, 39

Stolidobranchia, 4 5 6 8 9 10 12 13 14 15 18 19
20 67

MEMOIRS OF THE QUEENSLAND MUSEUM

Stomozoa, 35 156 157
australiensis, 157-9 161 250
bellissima, 159-61 250
murrayi, 157
roseola, 156 157 159
Stomozoidae, 4 8 9 10 13 14 16 19 20 35 156-7
162
Styelidae, 9 13
Sycozoa, 689 10 12 13 14 15 16 17 19 81 82
83 84 110 137-40 162
anomala, 13 137 138 140 143
arborescens, 139 140 153
brevicauda, 16 137 138 140-2 146 152
cavernosa, 138 139 140 142-3 149 155 156
cerebriformis, 82 137 138 139 143-6 152 249
gaimardi, 140
georgiana, 139 140
kanzasi, 139 140 152
mirabilis, 140 143
murrayi, 138 140 146-7 156 250
pedunculata, 138 139 140 147-9 152 153 155
156 250
perrieri, 155
pulchra, 2 16 137 138 139 140 142 147 149
149-52 153 155 156 250
quoyi, 153
sedens, 100
seiziwadai, 138 139 140 146 147 152 152-3 154
sigillinoides, 137 138 139 140 146 147 149 152
153-6
tasmanoides, 146
tenuicaulis, 149
umbellata, 153
Synclavella, 35 61
australis, 39 58
lessoni, 58
Syndiazona, 24 25
chinensis, 25 26 30

Tethyum sociabile, 21

Tetrazona, 162

Tylobranchion, 24 25 30 31
speciosum, 33

267

THE AUSTRALIAN ASCIDIACEA,
PHLEBOBRANCHIA AND STOLIDOBRANCHIA, SUPPLEMENT

Patricia Kottr

Kott, P. 1990 6 30: The Australian Ascidiacea, Phlebobranchia and Stolidobranchia, Supplement. Memoirs of
the Queensland Museum 29(1): 267-298. Brisbane. ISSN 0079-8835.

This supplement to the Australian Ascidiacea Part | (Kott 1985) is based largely on new collections of material
from southwestern and southeastern Australia (Albany and Western Port), and southeastern and northern
Queensland (Moreton Bay and Torres Strait). New species of the genera Perophora, Polycarpa (2), Eusynstyela,
Polyzoa (2), Botryllocarpa and Pyura are described. The previously known geographic range in Australia is extended
for Microgastra granosa, Cnemidocarpa tripartita, Polycarpa aurita, P. flava, P. lucilla, P. nota, P. plenovata,
Polyandrocarpa sparsa, Stolonica australis, S. nodula, §. reducta, Metandrocarpa miniscula, Botryllus stewartensis,
B. tuberatus, Pyura tasmanensis, P. arenosa, Halocynthia papillosa, Microcosmus madagascarensis, M. planus,
M. stoloniferus, Hartmeyeria formosa, Molgula calvata, M. incidata, M. rima, Eugyra millimetra and Pareugyrioides
exigua. The deep water Antarctic Cnemidocarpa barbata, and western Pacific Microcosmus curvus are newly
recorded from Australia. Additional morphological data for many of these species and for Crenicella antipoda,

and new ecological data for Polycarpa fungiformis is recorded. 0) Indo-West Pacific, Ascidiacea, Phlebobranchia,

Stolidobranchia, biogeography.

Patricia Kott, Queensland Museum, PO Box 300, South Brisbane, Queensland, 4101, Australia; 7 July, 1988.

Ascidians of the suborders Phlebobranchia and
Stolidobranchia were reviewed by Kott (1985).
Examination of more recently collected, as well
as previously unsorted material has expanded the
known geographic range of some species, and has
added new records and new taxa to the known
Australian fauna. This information supplements
that presented by Kott (1985).

New records, or newly observed variations in
morphology, are presented only where these are
outside previously known ranges. For detailed
data on distribution, the registration records of
Australian museums must be consulted.

Museum registration numbers are given for all
examined material. Abbreviations used are AM
(Australian Museum), SAM (South Australian
Museum), QM (Queensland Museum) and MV
(Museum of Victoria).

Suborder PHLEBOBRANCHIA Lahille, 1887

Family PLURELLIDAE Kott, 1973
Genus Microgastra Kott, 1985

Microgastra granosa (Sluiter, 1904)
Ascidia granosa Sluiter, 1904, p. 36.
Microgastra granosa: Kott, 1985, p. 70 and synonymy.
Ascidia (2) aenigmatica Nishikawa, 1986, p. 177.

DisTRIBUTION

New Recorps; Queensland (Moreton Bay, QM
GH3891 GH3896). specimens were taken at about 6m
attached to loose coral rubble on a sandy substrate off
Dunwich, Stradbroke I.

Recorpep Rance: Moreton Bay and north along
the east coast of Australia, Indonesia, Sri Lanka. With

the recognition of Ascidia aenigmatica Nishikawa as a
synonym the species range is extended to Japan.

DESCRIPTION

The newly recorded specimens are laterally
flattened, the left side lying on the substrate, and
the right side raised into a low dome. The atrial
aperture is halfway along the body toward the
side of the upper low dome-shaped surface. Entire
specimens are from | to 2cm long. A fragment
of a larger specimen consisting of a long (2cm)
atrial siphon and part of the test and body wall
at its base indicates that larger specimens do occur.

Family PEROPHORIDAE Giard, 1872
Genus Perophora Wiegmann, 1835

Perophora sabulosa n.sp.
(Figs 1,2)
DISTRIBUTION

Type Locatity; Queensland, Moreton Bay off
Dunwich, dredged 6m, coll. P. Kott, 26.8.86, holotype
QM GH3894, paratypes QM GH3902; Point Lookout,
North Stradbroke |., in rock crevices, intertidal, coll.
P. Kott 12.5.87, paratype QM GH4265.

FurtHer Recorps: Queensland (Moreton Bay QM
GH3892-3; Point Lookout QM GH4264 GH4279). One
specimen lot (QM GH4264) is part of a sand adapted
fauna found high in the intertidal zone in rocky outcrops
on a sandy beach.

DESCRIPTION

Colonies consist of branching basal stolons on
which spherical zooids of 3 to 4mm diameter are
supported on short stalks of about Imm, Basal
stolons, stalks and zooids are completely covered
with sand. Sometimes colonies are quite compact,

268

with adjacent zooids adhering to the sand on one
another’s test. The test is delicate and fragile
despite the embedded sand. Apertures are quite
close together on the terminal free end of each
zooid, Each aperture and its fringe of 10 small,
pointed lobes is obscured by sand.

The body wall is delicate. It contains a
conspicuous vascular network that obscures the
fine muscles, some radiating from the short
siphons, and others crossing the dorsal mid-line
behind the atrial siphon and sweeping ventrally
and posteriorly. Muscles are conspicuous only on
the anterior half of the body, fading out
posteriorly. There are 24 branchial tentacles of
various sizes, some quite long. The neural duct
has a simple, vertical, ciliated opening on the
dorsal tubercle.

The branchial sac has 11 rows of about 16
stigmata and about 12 internal longitudinal
branchial vessels. The gut forms a simple loop
across the posterior end of the body, and a short
rectum curves anteriorly at right angles to it. The
small, smooth stomach, narrowing to the intestine
at its distal end, is in the middle part of the
proximal limb of the gut loop. The oesophagus
curves anteriorly to open into the stomach a short
distance along its posterior border. Gonads are
in the gut loop, the testis follicle deeply divided
into about 5 long, parallel lobes, and the ovary
a small cluster of eggs at the distal end of the
male follicle. Small, almost spherical larvae, about
0.5cm diameter, lie in the right peribranchial cavity
of specimens collected in June.

Remarks: As new species of Perophoridae are
described definitions separating Perophora from
Ecteinascidia based only on the number of rows
of stigmata are increasingly unsatisfactory. Kott
(1985) redefined the former genus as having a
horizontal gut loop, a short rectum, and relatively
fewer and larger male follicles than Ecreinascidia.
However, as Monniot and Monniot (1987) have
suggested, the length of the rectum appears to be
a secondary character related to the length of the
branchial sac rather than being a plesiomorphic
character distinguishing Perophora from Ecteinas-
cidia, Perophora multistigmata (see Kott 1985)
and the present species, both with § or more rows
of stigmata, have a longer rectum than species
with 5 or fewer rows. Nevertheless, there are two
groups of species — those with numerous, small

Figs 15: Perophora sabulosa n.sp. (holotype QM GH3894) -
the test, viewed from the left. Cnemidocarpa barbata (AM Y2126)

MEMOIRS OF THE QUEENSLAND MUSEUM

male follicles and those with few, large male
follicles. The type species of Perophora, P. listeri
Forbes and Hanly, 1848, has the latter type of
testis and the type species of Ecreinascidia, F.
turbinata Herdman, 1880, has the former type.
The distinction based on the form of the testis
follicles is a valid amendment to the definition
of the genera.

Accordingly, the present species, despite its
unusually large number of rows of stigmata, is
assigned to Perophora on account of its single
testis follicle with relatively few, long branches.
Perophora multistigmata Kott, 1952 a possibly
related species (which, like P. sabulosa, appears
indigenous to Moreton Bay, has more than 5 rows
of stigmata, a similarly lobed male follicle, and
a similar colony) is distinguished by its naked test,
larger zooids, long siphons and 8 rather than 11
rows of stigmata. Unlike P. multistigmata, P.
sabulosa appears to be adapted for sandy habitats,

Perophora faaopa (Monniot and Monniot,
1987), from Tahiti, has 2 male follicles (lobed as
in the present species), numerous (15) rows of
stigmata, and zooids which lie on their left side,

Suborder STOLIDOBRANCHIA Lahille, 1887

Family STYELIDAE Sluiter, 1895
Subfamily STYELINAE Herdman, 1881
Genus Cnemidocarpa Huntsman, 1912

Cnemidocarpa barbata Vinogradova, 1962
(Figs 3-5)
Cnemidocarpa barbata Vinogradova, 1962, p. 202.
Monniot, 1978, p, 189.

Dist RIBUTION
New Recorp; New South Wales (24°27’S, 151°27'E,
AM Y2126). The specimens were taken from 1,200m,
the greatest recorded depth for this species,
Recorpe1 RaAnGer: Indian Ocean (64° 15'S, 107°33’E,
639 m, Vinogradova 1962; Kerguelen Continental Shelf,
Monniot 1978).

DescrRiPTION

The new record is of two specimens. They are
both upright and oval, 1.2cm high and Icm in
diameter with apertures on the upper surface and
the characteristic beard of hair-like roots from a
limited area at the posterior end of the body. In
these specimens the roots are slightly postero-
dorsal so that the branchial aperture is terminal,

I, portion of a colony; 2, body removed from
3, external appearance; 4, part of antero-

dorsal region of the pharynx showing branchial tentacles and dorsal tubercle, 5, left body wall showing gut,

gonads and endocarps. (Scales: 1, 3, 5 -

2mm; 2, 4 — 0.5mm),

THE AUSTRALIAN ASCIDIACEA |. SUPPLEMENT 269

yi

270

and the atrial aperture turned to the side. The
4-lobed apertures, on slight conical swellings, are
obscured by the fine folds of test that radiate from
each. The test is thin and translucent, with fine
rounded papillae giving it a granular appearance,
and horizontal wrinkles anteriorly that possibly
result from contraction.

There are very fine longitudinal muscles in the
body wall, and circular ones confined to the
siphons. About 16 branchial tentacles of very
different lengths, some very long, and others short,
alternate with one to 3 rudimentary ones, The
tentacular ring is separated from the peripharyn-
geal groove by a moderately wide prebranchial
area. The anteriorly directed C-shaped opening
of the neural gland is on a small papilla projecting
forward in the mid-dorsal line. The dorsal lamina
is a plain-edged membrane. There are 3 low
branchial folds on each side with very wide, flat
expanses of branchial wall between them. Internal
longitudinal vessels have the formula
E8(9)8(18)13(15)4DL3(10).... The most dorsal fold
on the left terminates anteriorly about half-way
up the dorsal lamina, and does not reach the
peripharyngeal groove. There are 3 or 4 stigmata
per mesh. The gut loop lies across the posterior
end of the body and is slightly curved. The
stomach, in the middle part of the ascending limb,
is short with about 20 parallel longitudinal folds.
The anal aperture, near the atrial opening, has
about 15 shallow rounded lobes, There are 4 or
5 irregularly shaped endocarps on each side of
the body.

A single long undulating gonad on each side,
extends postero-dorsally from about half-way
along the ventral part of the body wall. In the
newly recorded specimens the left oviduct opens
in the base of the secondary gut loop.

There is a ring of very fine tentacles around
the edge of the atrial velum.

REMARKS: The external appearance of the newly
recorded specimens agrees well with those
previously recorded, as do most of the internal
organs. There are some variations in the branchial
folds, although the total number of internal
longitudinal vessels recorded by Vinogradov
(1962) and Monniot (1978) are the same as in the
newly recorded specimens. There is some variation
in the number of anal lobes — Vinogradova (loc.
cit.) recording a bilabiate anal border while
Monniot’s specimen appears to have had about
10 lobes (Monniot 1978, fig. 7D).

Characteristics of the present species are the
tendency to loss of folds in the branchial sac, the
beard of hair-like roots from a limited area of
the posterior end of the body, the single undulating

MEMOIRS OF THE QUEENSLAND MUSEUM

gonad on each side, and the short stomach with
numerous longitudinal folds.

Cnemidocarpa digonas Monniot and Monniot,
1968 from much deeper water (2197 to 4008m)
from the northern and southern Atlantic (Monniot
and Monniot 1982) resembles the present species
externally, and in its branchial sac and endocarps.
It differs in its gut, in the number of stomach
folds and in the form and number of its gonads.

Cnemidocarpa bythia (Herdman, 1882), which
has similar gonads, also resembles the present
species externally; and it has been recorded from
the Tasman Sea (Millar 1959). However it is taken
at greater depths (4000 to 7000m) than the present
species, and it has a deep peritubular area, dorsal
languets and fewer stomach folds.

Cnemidocarpa tripartita Kott, 1985
Cnemidocarpa tripartita Kott, 1985, p. 140.

DisTRIBUTION

New Recorp; South Australia (Spencer Gulf, AM
Y¥2129). The specimen is from 32m.

RecorDeD RANGE: Victoria (Bass Strait),

The new record suggests that this small species has
a wider range in southern Australian temperate waters
than was formerly recognised.

DESCRIPTION

The newly recorded specimen has the same oval
shape, sessile apertures and reduced branchial sac
as the type material. The ovaries are character-
istically lobed, and undulating, with testis follicles
in clumps between the lobes as in C. /obata (Kott,
1952). However the newly recorded material
differs from the type in having two rather than
three gonads on the left side.

Genus Polycarpa Heller, 1877
Polycarpa aurita (Sluiter, 1890)

Styela aurita Sluiter, 1890, p. 338.
Polycarpa aurita: Kott, 1985, p. 152 and synonymy.

DisTRIBUTION

New Recorps: Queensland (Torres Strait, QM
GH4289-30 GH4844).

Recorpep RANGE: Northeastern Australia to Port
Jackson, north-western Australia to Cockburn Sound,
the Gulf of Carpentaria, Indonesia, the tropical western
Pacific (New Caledonia and the Philippines) and the
Atlantic Ocean (Gulf of Mexico and the Caribbean),

DESCRIPTION

The newly recorded specimens are 2 to 4cm long,
laterally flattened, and have sand adhering to
projections from the test to form a thick sandy
coating. Sand can be seen from the inside of the
tough, but thin and translucent test.

THE AUSTRALIAN ASCIDIACEA I. SUPPLEMENT

The branchial sac ts especially tough and
fibrous, It has the characteristic wide. flat
connectives altaching the transverse vessels to the
parietal body wall, In these specimens the
transverse Vessels themselves are especially
conspicuous, being filled with tough white libres
which have not previously been reported for this
species. These fibres are like those found in the
branchial vessels of Polvcarpa obscura (see Kott
1985).

Polycarpa directa n-sp.
(Figs 6,7)

Disteiurios

Tret Locatiiy- Victoria, Crib Pt, Western Port, 15m.
fine sand and mud, Crib Pomt Survey. Marine Studies
Group, Fisheries and Wildlife Department 9,3,65,
lrolotvpe MV £54203, paratypes MV F5329% F53306.

Furtire Recorps; Vietona (Crib Pt, MV F53315
f F53354 F53357 F54207).

Descriprion

The more or less egg shaped body. rounded
unteriorly, is 1.5 to 2em high and about 0.7mm
maximum width. The terminal branchial aperture
is directed obliquely upwards, away from the atrial
aperture which is on a rounded knob about one-
third of the body length down the dorsal! surface.
projecting away from it rather like a stumpy
thumb. Posteriorly there is a beard of fine,
branching, hair-like roots that conceal the pointed
posterior end of the body. The small area around
each aperture (s naked and the test is gathered
in around the opening. The rims of the apertures
do not appear to be lobed, The remainder of the
lest is covered with a dense coat of sand. The
body wall is muscular, with an outer layer of
crowded circular fibres and inner longitudinal
hands. A tiarrow branchial velum is present
anterior to the ring of about 50 fine branchial
tentacles of various sizes. The peripharyngeal
groove runs straight across the anterior end of
the dorsal lamina without forming a V-shaped
peritubercular area and the prominent dorsal
tubercle, with a conspicuous U-shaped slit, is in
the dorsal mid-tine in the centre of the prebranchial
area. The dorsal lamina is long and straight.

The branchial sac is very much contracted in
these specimens and docs not extend posterior to
the oesophageal opening which is about two-thirds
of the distance down the body. Both the transverse
and internal lengitudinal vessels are thick and
obscure the stigmata, of which there are about
4 per mesh in the centre of the branchial sac. The
branchial formula is E0(8)1(8)1(6)1(12)0DL,
((9)3(8)1(10)1(8)OE. The dorsal fold on the left
is very close to the dorsal lamina.

271

The simple. almost straight and relatively
narrow gut loop projects almost Vertically behind
the branchial sac, The oesophagus 1s short and
the stomach pear-shaped, increasing in width
toward its pyloric end where a moderately long
gastric caecum projects into the pole of the loop.
The stomach wall has § broad longitudinal folds.
The anal opening, its rim divided into 16 rounded
lobes, is only slightly anterior to the oesophageal
opening.

Flask-shaped polycarps of various sizes are
scattered over the anterior two-thirds of the body
wall, their narrow tapering ends directed toward
the atrial aperture. There are 2 rows of pyriform,
unbranched male follicles beneath each ovary,
Numerous small endocarps are scattered between
the gonads and posterior to them. Both gut loop
and gonads are only lightly attached to the body
wall,

Remarks: Characteristic of this species are
its shape and the course of the gut. with the body,
and the vertically oriented gut loop projecting
behind the pharynx, und into Lhe pointed posterior
end of the body. These characters can be used
to distinguish the species from P. papyra with
which it otherwise shares a position m the key
to the Austcalian Polyearpa (see Kott 1985),
However it does not appear to have a close relative
in the Australian fauna.

Both Polycarpa sobria and P, plenavala have
4 gastric caecum but lack endocarps between the
scattered polycarps and have horizontally onented
gut loops and deeply curved branchial sacs.
Polycarpa nvia does have small endocarps
scattered amongst the gonads, and a gastric
caecum. However it also has several endocarps
scattered in the gut loop while there are none itl
that position in the present species.

Polycarpa flava Kott, 1985

Polycarpo lave Kot, 1985, p. t65 and synonymy.

Dish kiguiion

New Recorns- Western Australia (Albany, AM). The
species is common in sea grass beds ( Posidenia australis
and P. simvosa).

Recorpen Rant South Australia (Great Australian
Bight, Spencer and St. Vincent Gulls). Tasmania (Bass
Strail. vastern coast), Victoria (Cape Wooloomai. Point
Nepean).

Description

Numerous specimens, all relatively small
(seldom more than lem long), are characteristi-
cally black in preservative, with a Lough wrinkled
test und sessile apertures. They are stalked or
sessile. What appear to be senescent specimens,

272

without gonads, have thinner test, and are less
contracted and wrinkled.

REMARKS: The external shape of this species
resembles that of Polycarpa fungiformis (see
below); and although their ranges do not overlap,
they appear to occupy a similar habitat in seagrass
beds. It is possible that the stalk and lower half
of the body of P. flava is embedded in the substrate
as it is in P. fungiformis. Both these species are
unusual amongst stalked species in having the
apertures relatively close together on the upper
surface (see Kott 1989).

Polycarpa fungiformis Herdman, 1899

Polvearpa fungiformis Herdman, 1899, p. 43. Kott, 1985,
p. 166 and synonymy.

DistTRIBUTION

Recorpep Rance: Moreton Bay, Queensland to
Lizard I.

Remarks: The species has been observed in
sparse seagrass beds in Moreton Bay with the stalk
and lower half of the body embedded in the
substrate (see P. flava, above). Many specimens
were fresh but torn and empty tests, the body
possibly removed by Dugong dugon which were
seen feeding in the area (A. Preen pers.comm.).

Polycarpa lucilla Kott, 1985
Polycarpa lucilla Kott, 1985, p. 171.

DistTRIBUTION

New Recorps: Western Australia (Albany, QM
GH4627). Queensland (Torres Strait, QM GH4832).

Recorpep RAnGe: Western Australia (Cape Jaubert).
South Australia (Upper Spencer Gulf). Queensland
(Gladstone — Townsville). The new records extend the
known tropical range of this species and confirm its
occurrence in temperate waters. Both of the records from
temperate waters (Upper Spencer Gulf and Albany) are
from sea grass beds.

Polycarpa kapala n.sp.
(Figs 8,9)
DisTRIBUTION
Type Locauiry: Off the New South Wales Continental
Shelf, 34°27’S, 151°2’E, 1,200m, FV Kapala St. 76-23-
02, coll. J. Lowry 3.12.76, holotype AM Y2123, paratype
AM Y2124.

DESCRIPTION
The holotype, slightly larger than the paratype,
is 6mm long, including the foraminifers that

MEMOIRS OF THE QUEENSLAND MUSEUM

adhere to the test in a dense coating. Individuals
are lozenge-shaped, more or less flattened dorso-
ventrally. Very long, branched, hair-like roots
penetrate through the coating of foraminifers
around the outer margin of the lower surface, but
are absent from the remainder of the body. The
almost sessile apertures, at opposite ends of the
upper surface, are surrounded by finer particles
adhering to the test than those over the rest of
the body. The test is very thin and delicate.

The body wall is delicate with a thin layer of
fine muscle bands. About 16 fine branchial
tentacles are of various sizes. The dorsal tubercle
is small with a simple longitudinal opening of the
neural gland. The dorsal lamina is very long,
extending the whole length of the dorsal surface.
The branchial sac is delicate. The relatively few
internal longitudinal vessels are present only on
the low folds, as in the formula
E0(4)0(5)0(2)0(5)ODL. About 8 relatively short,
rectangular stigmata per mesh are present in the
interspace (between the folds), but only one or
2 in the meshes on the folds. There are only 8
rows of stigmata and no parastigmatic vessels. The
second fold from the dorsal line is always the
smallest.

The gut forms a small, simple loop at the
posterior end of the body, just below and to the
left of the atrial aperture. The oesophagus ts short,
and the short almost spherical stomach, with about
8 deep folds, occupies most of the ascending limb
of the gut loop. The short wide post-pyloric part
of the gut curves around from the distal end of
the stomach to open in a smooth-rimmed anus
near the atrial opening. On the right are 2 short
oval polycarps longitudinally oriented in a line
parallel with the longitudinal axis of the body.
A single one is on the left. The ovary is oval and
sac-like with a short terminal duct. A single male
follicle lies beneath the ovary, its duct passing
around the dorsal side of the ovary to open on
its mesial surface at the base of the oviduct.

There are 4 or 5 long irregular endocarps on
each side of the body.

Remarks: Only 10 species of the genus
Polycarpa have been described from 1000m or
more; and the great majority of these have been
described by C. and F. Monniot (1968, 1974;
1977a,b; 1985) and C. Monniot (1970), mainly
from the Atlantic Ocean. Only one species,

Figs 6-12: Polycarpa directa n.sp. (holotype MV F54203) — 6, external appearance; 7, internal organs. Po/lvcarpa
kapala n.sp. (holotype AM Y2123) — 8, external appearance; 9, internal organs. Po/ycarpa nota (QM GH4278)
— 10, internal organs, Eusynstyela grandis n.sp, (holotype QM GH4281) — 11, external appearance; 12, body

removed from test, viewed from dorsal surface. (Scales: 6, 7, 12

2mm; 8, 9, 10 — Imm; I! — 5mm).

THE AUSTRALIAN ASCIDIACEA |. SUPPLEMENT

cS

ete

aaage

e

a74

Polycarpa indiana Movviot and Monniot, [985
(> P. albatrassi » Millar, 1959), bas been taken
from the Indian Ocean.

The present species is apparently the first of
the penus to be recorded from the Paeilic
Ocean,

All the Known species of Polvearpa from deep
waters show convergent adaptations probably
associated with their small sive They are also
similar to small, interstitial species of this genus
that are found in shallow water, indicating that
the morphology is the result of small sive rather
than an adaptation associated with deep water
habitats, These small species are invariably
invested with 4 coatimy of foraminifers and other
particles that adhere to their test. and most have
long, branched, hiwir-like reaots from the under
surfaces, although a few are stalked. The branchial
folds are low, and sometinves are Jost altogether,
the number of rows of stigmata is reduced trom
that Known in larger species, and the number of
internal Jongitudiowl vessels is reduced — these
vessels often being completely absent fram the
interspaces between the folds. The gut is always
reduced in length, uyually lormiry, a sumple loop
in the postero-dorsal part of the body, The gonads
ure generally characteristic of the genus, although
they are seldom as numerous as in most larger
species of the continental shelf, and the number
of male follicles is usually reduced, often to one
or 2 in each polyearp.

The minimum number of polycarps, one or 2
per side, is recorded for P. pseddoalbarrossi
Monmolt and Monniwt, l968, 7. bixcavertsiy
Monniot and Monniot, 1977a and P. tera
Monniot and Monniot, 1977b as well as in the
present species. However the 3 Atlantic species
ure distinguished by the loss of some of the
branchial folds, while in P, kapala all 4 are present
on each side. Of the previously described species.
P. perculus Monniot and Monniot, 1979, from
relatively shallow water (250m) in the northern
Atlantic Ocean olf Norway, most closely resembles
the present species, Polyearpa porcufuy has only
2 or 3 gonads on each side, each cansisting of
au large sae-lke ovary with one or more male
follicles, internal longitudinal vessels are absent
from the iterspaces, and the number on the folds
varies between 3 and 7, the smallest fold being
the second from the dorsal line. However, its
gonads are spherical rather than oval, it has a
Jong curved gastric caeeum that is not present in
P. kapala, and the apertures are close together,
rather than being at opposite ends of the body.
These differences suggest that the resemblance
between P. Aapala and P. porculus are the result

MEMOIRS OF THE QUEENSLAND MUSRKUM

of convergence rather than being indicative ol a
elose relationship.

Polvearpa is vy predominantly tropical genus
(thal, in shallow shelf habitats, appears to be
subject to isolation and speciation in temperate
waters (Kott 1985). It is not a diverse genus in
deep slope and abyssal water, where, again, its
species have a conspicnously limited geographic
range in comparison with species of other
phlebobranch and stolidobranch genera. The
pattern of its colonisation off the continental shelf
muy therefore be similar to that in temperate
waters viz. through speciation of isolated
populations, in this case isolated from those on
the adjacent continental shell, The larval strategies
that contributed to the inhibition of gene flow
in temperate waters may very well have the same
effect in shelf and abyssal waters and prevent the
establishment ol Polveurpa species with wide
geographic ranges in the ocean slopes and basins.
Polvcarpa is not known {rom either shelf or deep
water habitats in the southern oceans — a tact
that tends to support the hypothesis that the sister
species of deep water lorms may be found on the
adjacent continental shelf.

Polycarpa nota Katt. 1985
(Fig. (0)
Polycarpa nala Kott. 1985, p. 176,
Polvearpa tiumida. Manniot and Monniot, (987, p. 117.

Dis tp rons

New Reeoorn Queensland (Moreton Bay. OM
GH4278 GH4280).

Recorpro Ranca Heron Island, Great Barrier Reel
and Freneh Polynesia (see Po tanida: Mannior and
Monniat,. 1987).

DESeRIPTION

‘The new record is of 2 speciinens taken from
mud flats at Myora Both specimens are about
L.Sem Jong, with the branchial aperture at one
end ol the upper surface and the atrial aperture
about half way along. The inconspicuous, 4 lobed
apertures are on very slight prominences and are
surrounded by the very tough wrinkled test which
is a dirty white colour in preservative. One
ypecimen Was fawn coloured when alive, dorso-
ventrally fattened, convex dorsally and attached
by a flat, wide base; and the other one was brown,
its body narrower, less attened, and attached by
a narrow strip along the ventral surface. The shape
of the body appears to be affected by the shape
of the hard shell or rock to which the individual
is altached.

Vhe body wall is a greenish-brawn colour in
the preserved material and there are 4 dark stripes

THE AUSTRALIAN ASCIDIACEA 1, SUPPLEMENT

in the wall of the short siphons. The prebranchial
area is wide, with an obtuse peritubercular V. The
dorsal tubercle itself is a prominent circular
cushion with a deep conspicuous C-shaped to
circular (one horn overlapping the other) slit. The
branchial tentacles are slender.

There are not more than 2 internal longitudinal
branchial vessels in the interspace, and up to 10
on the dorsal folds — which are larger than the
others. Four to 6 stigmata are present in each
mesh in the interspace in the centre of the branchial
suc. The gut forms a narrow loop around the
postero-ventral curve of the body, extending about
halfway up the ventral surface. The stomach has
about !2 deep, longitudinal internal folds. It
oecupies the middle one-third of the ascending
limb of the gut loop, The anal border is divided
into small, rounded lobes. The oval gonads are
crowded in 2 to 4 rather regular rows. The
gonoducts are directed dorsally. Where only 2
rows of gonads are present they are in the ventral
half of the body wall, but 4 rows cover the ventral
three-quarters. The gonads are anterior and dorsal
to the gut loop on the left. Between the gonads
are upright, flattened endocarps. Sometimes they
expand at the top and sametimes they are lobed.
There are also about 5 similar endocarps crowded
into the distal part of the gut loop. These obseure
the large gastric caecum that curves around in
the loop of the gut, and is attached to the intestine
by the gastro-intestinal ligament,

Remarks: The newly recorded specimens are
larger than the holotype; the gonads are more
numerous, larger and more crowded; there are
more numerous internal longitudinal branchial
vessels; the gut loop is longer; and although dark
Stripes are present in the wall of siphons. they
are not present in the test around the siphons —
aus they are in the holotype. However, these
specimens agree with the holotype in their tough.
externally wrinkled jest. the position and torm
of the apertures. the law rounded branchial folds,
the length and structure of the stomach and the
general form and distribution of gonads and
endocarps.

Monniot and Monniot (1987) have assigned
specimens from French Polynesia to the Atlantic
species Palyearpa tumida Heller, 1878 (see
Monniot, C. 1972, and Polvandrocarpu sabanillae:
Van Name, 1945). Not only is the latter species
geographically isolated from P. nota. but also it
is distinguished from it by its aggregating habit.
its more numerous internal longitudinal branchial
vessels (up to 17 on a dorsal fold in a 2cm
individual; see Van Name, 1945), short and
inconspicuous gastric caecum, interrupted and

275

irregular stomach folds, and only a moderately
projecting dorsal tubercle with a variable but more
or less convoluted sht.

Minute projections similar to those that
Monniot and Monniot (1987) desenbe as atrial
tentacles on an atrial velum ol! the French
Polynesian specimens are present in those newly
recorded from Moreton Bay, However, in the
latter they are on the lower part of the siphonal
linings af both siphons — on the membrane from
the body wall that covers the lower part of the
lest Where it turns in to line the outer part of
the siphons

There is some disparity between the structure
of the dorsal tubercle of the newly recorded
specimens and that described for those from
French Polynesia which are reported to have
circular erater-like opening turned to the left.
Superficially (see Monniot and Monniot 1987 fig.
46) these tubercles resemble those of the Moreton
Bay specimens, The tubercle itself is transparent.
and the whole depth of the ciliated pit is clearly
seen. [tis deep and vertical. and its sides are folded
toxether to form the usual cleft that opens on the
surface of the tubercle in a narrow slit, Each end
of this cleft progressively curves in. eventually
forming a cylinder with one end overlapping the
other, The concave side of the curve is toward
the left. There is no sign of the circular opening
on the left that Monniot and Monniot (/ac. cit.)
have recorded, although the gap between the ends
of the cleft is present in this position,

The French Polynesian and Australian speer
mens are otherwise identical, The species 1s
apparently part of the wide-spread Indo-West
Pacific fauna, The small size and eryptic habitat
of this species have apparently previously caused
it to be overlooked, although it is said to be the
most common species in French Polynesia
(Monniot and Monniat 1987).

Polycarpa plenoyata Kott, 1985
Polvearpa plenovaia Kort, V985, p 194

DISTRIBUTION
New Recokp Vietona (Crib Pe, Western Port, MV
FS53331). The single specimen was taken fram [3r,
Rrcorpen Raxcre The species previously was
recorded from Bass Strain 7) to #4

Drserie non

The specimen is identical with the type material
except that there are 2 (rather than one) paralle!
transversely wrinkled stalks from the postero-
ventral corner ef the body. The siphons are
contracted into wart-like knobs but are probably
very long When extended,

276

Subfamily POLYZOINAE Huartmever, 1903
Genus Polyandrocarpa Michielsen, 1904

Polyandrocarpa sparsa Kott, 1985
Palvandracarpa sparsa Kou, 18S, p. 222.

Drs ten tion

New Rreaeis New South Wales (Byron Buy. AM
Y¥ 2130), ? location, AM Y2/68, The collector has noted
that the specimens, from Byron Bay, taken at lm, were
foOMMon at this location,

Recon Rawor: The newly recorded location is
on the northern New South Wales coast, extending the
tange anly slightly trom the type locality an Nerth
Sohitury

Genus Eusynstyela Michaclsen, 1904

Kusynostyela grandis rsp.
(Figs 11,12)

DistRint nan

Type boeartey, Wistar Reel, Capricorn Group,
Great Barrier Reel, under rubble near reef crest, low
tide, coll. 7. Rott 5.11.86, holotype QM GH4281.
Drsorierion

The holotype colony consists of 4 large vaoids
embedded in common test. The dorsal surface of
each zooid protrudes from the upper surface of
the colony as a long (1.6em) oval swelling.
Branchial and atrial apertures are both more or
less quadrilateral. In preserved specimens bluc
iridescent stripes extend down each siphonal
lining, ane from the centre of cach of the 4 sides
of the aperture. The apertures are, respectively,
about one-third of the zooid Jength from the
anterior and posterior ends of cach soon. ‘The
living colony is an even brick red colour and
smooth, but wrinkled when contracted, The test
is tough and leathery on the upper surface, but
the busal test, attached to the substrate. is very
thin and transparent. The zouvids hie on their
ventral surtace and the body wall is folded around
the meridian about half way down each side.

Generally the body wall is delicate. There are
strong circular muscles around each low conical
siphon and around the base of each siphon. Fine
longitudinal muscles radiate from each siphon
across the upper (dorsal) half of the body and
curve around the fateral meridian, but they do
mot extend across the lower (yentral) surface. The
yentral body wall is very delicale, and closely
associated with the equally delicate test. Living
specimens have white lorivitudinal stripes - 4
thick ones alternating with 4 thinner ones — in
the siphonal lining. About 24 simple branchial
tentacles alternate with rudimentary ones.

The opening of (he neural gland is a simple,
Jong, vertical slit, in a fairly long, oarrow

MEMOIRS OF THE QUEENSLAND MUSEUM

peritubercular area. The dorsal lamina ts a plain-
edged, broad membrane. The endostyle is long.
There are 4 branchial folds on each side. Internal
longitudinal vessels haye the formula
E1(5)3(6)3(10)4(12)1DL. There are about 6 long
rectangular stigmata per mesh between the folds
in the centre of the branchial wall.

The oesophagus is fairly long. first extending
posteriorly and then bending abruptly around the
posterior end of the branchial sac, to open into
the stomach on the ventral surface of the body
wall. The long stomach, oceupying about the
middle third of the ascending limb of the gut loop
has [6 long parallel folds in its wall. The whole
of the ascending limb of the gut Joop (including
the stomach). is parallel to the longitudinal axis
of the body. A fat collar of the body wall projects
lroam inside the gut loop at the junction of the
stomach with the intestine, but there is mo cuccum.
A ligament containing the gastro-intestinal duct
(from the stomach to the intestine) extends from
the outer rim of the collar, The primary gut loop
occupies about hall the length of the ventral
surface of the body, and the short reetum bends
sharply around the lateral meridian to open at
the base of the atrial siphon by an &-lobed anal
opening.

There is a single row of shart oval polyearps
along cach side of the endostyle — up to 12 on
the right and 10 on the left. These consist of a
single, entire male follicle beneath each sac-like
ovary, The short male duct curves around the side
of the short oviduct to open on top of it. Along
each side of the endostyle. the body wall,
containing the polycarps. is embedded in the thin
basal lest, Here the test accommodates irregulat-
ities of the substrate and the polycarps are thus
protected amongst these irregularities. There are
small, sometimes crowded endocatps around the
lateral meridian of the body

Remannxs: The species is characterised by its
large 7ooids. single testis follicles, absence of a
gastnic caecum and presence of a collar of the
internal parietal body wall in its place. lobed anul
border, and the embedded section of the body
wall (with its contained gonads) in the test. The
internal longitudinal branchial vessels are rela-
lively more numerous than those of £. larericius
and the rows of polycarps are closer to the ventral
line, although the course of the put in the posterior
end of the body is rather similar in these two
species,

fusyastvela monotestis Tokioka, 1953 from
Japan and Polvandrocarpa (Monandrocarpa)
farona Monniet and Monniot, 1987 (> Buyer
stvela taruna) from ‘Tahiti are the only other

THE AUSTRALIAN ASCIDIACEA 1. SUPPLEMENT

known Pacific species of this genus with a single
male follicle. The former is distinguished from E.
grandis by its upright zooids, horizontally oriented
stomach with a gastric caecum, long rectum and
smooth anal border, Although Eusynstvela tarona
has dorso-ventrally flattened zooids and similar
gut loop and gonads to those of the present species,
its zooids are only 4 to 5mm long and it has a
long, curved gastric caecum.

Polyandrocarpa maxima (Sluiter, 1904) has
zooids up to |.7cm long that he on their ventral
surfaces, are embedded in common test like those
of the present species, and have a similar branchial
sac and stomach, Kott (1985) suggested that it
could be a species of Eusynstyela, It is distin-
guished from the present species by its horizontal
rather than longitudinally oriented gut loop and
its smooth rather than lobed anal border.

The tendency, in this genus, for gonads to
project out from the body wall into the test, has
been discussed by Kott (1985) and compared with
the situation in Seriocarpa where the test protrudes
into the body wall to encase the gonads.

Genus Stolonica Lacaze Duthiers and Delage,

1892
The type species of Stolonica, S. socialis Hart-
meyer, 1903 — erroneously referred to as S.

australis Hartmeyer, 1903 in Kott (1985) — has
2 rows of lobed, male gonads, with an accessory
row anterior to the gut. In the posterior part of
the row on the right side of the endostyle there
are ovaries associated with the male gonads.
Zooids are joined by stolons, the branchial sac
is folded, and there are numerous internal
longitudinal vessels. The male gonads consist
always of a single follicle, although it Is often
lobed, sometimes quite deeply. However, these
lobes are not separate follicles as Michaelsen
(1922) and Berrill (1950) state them to be.

AS new species with the general characteristics
of this genus have been described, the definition
of the genus has been amended to accommodate
species with different arrangements of male,
female and hermaphrodite polycarps.

In Michaelsen’s (1922) amended definition of
Stolonica the polycarps are arranged (as in the
type species) in a row on each side of the body,
the left row with male organs only and the right
with male organs anteriorly and hermaphrodite
organs, posteriorly. In the same work, Michaelsen
defined Amphicarpa as having irregularly distrib-
uted male, female and hermaphroditic polycarps
on each side of the body.

Colonies of Stolonica australis Michaelsen,

277

1927 from Albany departed from the genus as
defined by having hermaphroditic as well as male
gonads on both sides of the body. Michaelsen
concluded that in the genus Sro/onica there existed
a range of arrangements of male and female
gonads from the type species S. socialis to
Amphicarpa. He further amended the definition
of Stolonica to comprise species with hermaph-
roditic and unisexual gonads on both sides of the
body near the ventral mid-line, the male gonads
often extending dorsally.

Kott (1985) included in Stolonica those species
in which large and often lobed male polycarps,
some with ovaries associated with them, are
limited to two rows, one each side of the endostyle.
Species in which numerous small, single male
follicles are found in patches outside the two
primary rows were assigned to the genus
Amphicarpa.

In both Amphicarpa and Stolonica spp. the
female gonads are often absent entirely from the
left side of the body. This appears to be an
intraspecific variation rather than a generic trait.
It may even be associated with maturity. The
proliferation of small male gonads, used by Kott
(1985) to distinguish Amphicarpa from Stolonica,
is also a character that is expressed in different
degrees at different stages within single species in
both genera. In some species assigned to Stolonica
(S. reducta, S. truncata and S. vesicularis) the
gonads are very strictly confined to two rows, but
in S. agnata, S. aluta and S. carnosa there is some
proliferation of male gonads posteriorly that
resembles the condition of the gonads in the type
specimens of Amphicarpa nodula Kott, 1985,
Further, the range observed in the condition of
the gonads in Stolonica australis and in Stolonica
nodula (> Amphicarpa nodula), both discussed
below, demonstrates the difficulties in distinguish-
ing these two genera, and reinforces a view that
the distinction is an arbitrary one.

Accordingly, the genera are here considered as
synonyms. The key that follows combines those
for Stolonica and its junior synonym, Amphi-
carpa, from Kott (1985).

KEY TO THE SPECIES OF STOLONICA
RECORDED FROM AUSTRALIA

1. Zooids embedded....S. carnosa Millar, 1963
Zooids joined by stolons ..........+-00005 2

2. Siphonal scales present ...............006.
pRalpga ye so: S. diptycha (Hartmeyer, 1919)
Siphonal scales absent .................--3

3. Gastric caecum present ............-.000. 4
Gastric caecum absent ............0..20065

ed cate sew pee wt S. duploplicata Sluiter, 1913

278
4. Branchial folds 4 per side ............0000-
bad eitak ne tbat saree ts S. agnata Kott, 1985
Branchial folds less than 4 per side ........ 5
5. Stomach folds 36; male gonads long,
branched ......... S. truncata Kott, 1972b
Stomach folds not more than 20; male gonads
not long, branched ............6-.00005 6
6. Branchial folds 2 on left ..............0.- 7
Branchial folds 3 on left ..............4.- 8
7. Stomach short with pronounced spur.......
ea Saag eneatthet S. vesicularis Van Name, 1918

Stomach long without pronounced spur.....

of odeint yaa] & ceo S. australis Michaelsen, 1927

8. Gastric spur present; about 20 rows of
StiPMAtas 12s ele bed tee S. aluta Kott, 1985
Gastric spur not present; 10 to 15 rows of
Stiornata fio Alec ace och 2 Re poaceck page agg ass 9

9. Gastric caecum very short and not curved....
fel onlin ae et ee dle gtione S. nodula (Kott, 1985)
Gastric caecum long and curved

§ Pa ncaa de 234 S. reducta (Sluiter, 1904)

Stolonica australis Michaelsen, 1927
(Figs 13,14)
Stolonica australis Michaelsen, 1927, p. 202. Kott, 1985,

p. 234 and synonymy.

Amphicarpa meridiana Kott, 1985, p. 246 and
synonymy.
DisTRIBUTION

New Recorps: South Australia (Price L., Avoid Bay,
QM GH4142 GH4197). Victoria (Western Port MV
F54204). Queensland (Peel I., Moreton Bay, QM
GH3879 GH4291).

RecorpepD RANGE: The species previously was known
from Albany, Western Australia, to the Solitary Is off
the northern NSW coast. The small specimens newly
recorded from Moreton Bay may represent the northern
limit of the range of this temperate indigenous species.

DESCRIPTION

The newly recorded colony from the Great
Australian Bight is large and cauliflower like
forming a dome about 10cm in diameter and 12cm
high. It is composed of crowded club-shaped
zooids, the larger ones about 2cm long, their
anterior ends around the outside of the dome,
narrowing posteriorly to broad stalks that join
with those of neighbouring zooids as they converge
toward the centre of the base of the colony. Smaller
spherical zooids are also present, branching off
the stalks and even off the sides of the larger
zooids. There is a layer of sand over the zooids
and their stalks. The apertures, sometimes sessile
and sometimes on small wart-like siphons, are
close together on the anterior free ends of the
zooids. From inside the body, the atrial aperture
is seen to be just dorsal to the neural ganglion.

MEMOIRS OF THE QUEENSLAND MUSEUM

About 60 branchial tentacles are of various sizes.
The dorsal tubercle has a long vertical slit.

The branchial sac has 2, long, straight folds in
its dorsal half, and ventrally a wide expanse of
flat branchial sac between the endostyle and the
first fold. Internal longitudinal vessels have the
formula E8&(10)6(9)ODL1(12)4(8)8E. There are 6
to 8 stigmata in a mesh in the centre of the
branchial sac, and 19 rows of stigmata, each
crossed by a parastigmatic vessel. Smaller
spherical specimens have fewer internal longitud-
inal vessels and stigmata, but they are present in
the same ratio, and the folds are dorsally
positioned.

The gut loop is short and obliquely oriented
postero-ventrally. A long rectum extends antero-
dorsally, more or less in line with the gut loop,
reaching well anterior to the oesophageal opening,
almost to the anteriorly positioned atrial aperture.
The gut loop is bent anteriorly forming a
secondary loop in the smaller spherical specimens.
The stomach has about 18 parallel folds. A short,
straight caecum and a very strong ligament from
the intestine passes over the centre of the stomach,
appearing to hold the folds of the narrower cardiac
end of the stomach in position.

There is a glandular collar around the intestine.
The gut loop encloses 2 endocarps, one in the
pole and one on the dorsal side of the gastro-
intestinal ligament. The gut loop is attached to
the parietal body wall by a series of short, strong
ligaments placed equidistant from one another
along its outer curve. The gonads are very variable
in the South Australian colony, and it is possibly
becoming senescent. In some zooids about 10 small
inconspicuous ovaries, each containing 3 to 4 eggs,
and a few, scattered, small, elliptical male follicles,
form a row along each side of the endostyle. In
others, the ovaries, in the rows along each side
of the endostyle, are directly associated with oval,
or club-shaped or circular testis follicles, and
smaller male follicles are in groups at the posterior
end of each row and spread into the postero-dorsal
part of the body wall. Three or 4 large, oval
endocarps are on the body wall on each side.

The newly recorded specimens from Moreton
Bay are small (up to 5mm diameter), dome shaped
and sessile on a basement membrane. In the living
material the orange zooids can be seen through
their sandy coat. There are about 30 crowded
branchial tentacles. The dorsal tubercle has a
longitudinal slit. The branchial folds are low, and
the branchial formula is E2(4)1(8)0DL. The gut
forms a short horizontal loop attached by the usual
ligaments to the body wall, and the rectum forms
a right angle with it. The stomach is short with

THE AUSTRALIAN ASCIDIACEA 1. SUPPLEMENT

about I5 folds and a slightly curved caecum. There
is a small endocarp in the pole of the gut loop,
another on the other side of the gastro-intestinal
ligament and a few long ones scattered on the
body wall. Immature hermaphrodite polycarps,
each consisting of a single circular male follicle
beneath a small circular ovarian sac, are arranged
in a row along each side of the endostyle, and
there are also a few scattered male follicles on
the body wall.

Remarks: The specimens described above from
South Australia are the largest known, although
otherwise the shape of the colony and the zooids,
the course of the gut, shape of the stomach, and
other characters resemble figured specimens
(including the type) of A. meridiana Kott, 1985
from New South Wales. Thetwo newly recorded
specimen lots are at opposite ends of the
morphological range of this species. The Queens-
land specimens are less than half the size of
previously recorded material, and only a little
more than one-tenth the length of the newly
recorded material from the Great Australian
Bight, and they have fewer internal longitudinal
branchial vessels, stomach folds and branchial
tentacles than the South Australian specimens.
However, specimens from both locations have
closely placed apertures, numerous branchial
tentacles, and longitudinal opening of the neural
duct, 2 branchial folds in the dorsal part of the
branchial sac, 19 rows of stigmata crossed by
parastigmatic vessels, a similarly shaped stomach
with a short caecum and broad folds, and the same
arrangement of gonads. The gut loop of the
Queensland zooids is bent up more than it is in
the long zooids from South Australia.

The structure of both lots of zooids falls within
the range previously reported for this species and
its synonyms. The arguments for the synonymy
of Amphicarpa and Stolonica are set out in the
discussion of the genera (above).

Stolonica nodula (Kott, 1985)
Amphicarpa nodula Kott, 1985, p. 247.

DISTRIBUTION
New Recorb: Queensland (Repulse Ils, QM GH4295).
Recorpep Rance: The species has previously been
recorded only from Abbot Bay, northwest of Bowen,
some 150km from the new location north of Mackay.

DESCRIPTION

The newly recorded specimens are firmly
attached to the test of a specimen of Microcosmus
helleri, forming a fairly crowded layer of zooids
around it. Individual zooids are stalked or sessile,
spherical to vertically elongated and club-shaped.

279

They are joined basally by wide membranes and
short irregular connectives. Both apertures are on
the more or less circular, and sometimes flattened,
upper surface of each zooid. Zooids and connect-
ing basal membranes are completely covered with
a layer of sand. This obscures the sessile apertures
which are surrounded by a small area of naked
test gathered in around the contracted rim of each
opening. The body wall is muscular, but closely
adherent to the test and not readily removed from
it. There is no pigment in the body wall of these
preserved specimens.

In most respects the morphology conforms with
that previously reported (Kott 1985). However,
the voluminous gut loop is rather variable in its
course, sometimes forming a rather wide, open
loop rather than a closed one; and the gonads
are variable. In the newly recorded specimens a
tow of about 6 to 8 hermaphrodite polycarps is
present on each side of the endostyle rather than
only on the right. Some of these polycarps contain
a single, large ovum. Other ova, embryos and
larvae are in the peribranchial cavity on each side,
and tend to distort the branchial sac and the course
of the gut. Testis follicles are not mature and there
is no sign of the accessory male glands that were
present in the Abbot Bay material (Kott 1985).

The larval trunk is 0.8mm long and the tail about
1.3mm long. The larval test around the trunk has
small, reddish vesicles scattered in it. The
epidermis has about 12 parallel longitudinal ridges
each terminating anteriorly in an epidermal
ampulla. There is a large photolith and the usual
3, triradially arranged, adhesive organs.

Remarks: Although it has not been reported
previously for this species, one of its most
conspicuous characters — confirmed by exami-
nation of the type mateial (QM GH702 GH1309
GH2308) — is the very close adherence of the
body wall to the test. Other distinguishing
characters, in addition to the 3 branchial folds,
are the fine, internal longitudinal branchial vessels,
short stomach, small gastric caecum, long and
voluminous intestine and rectum, and the two
large lips of the anal opening.

The dark colour of the body wall observed by
Kott (1985) in freshly formalin-preserved speci-
mens is no longer present in the same material
now in alcohol.

The gonad arrangement described by Kott
(1985) for the Abbot Bay material is not found
in the new material, which has zooids with
hermaphrodite polycarps on both sides of the
body, mature ova and embryos in the atrial cavity,
and only a single large ovum in each polycarp
on the body wall. Thus, although there are 2 or

280

3 eggs in the ovaries previously described, it
appears from the present specimens that only one
matures at a time,

Variation in the condition of the gonads
observed in this species is similar to that observed
in Stelonica australis (see above), and supports
the view that Amphicarpa is a synonym of
Stolonica.

Stolonica reducta (Sluiter, 1904)
(Fig. 15)
Strela reducta Sluiter, 1904, p. 72.
Stolorifea reduera: Katt, 1985, p. 236 and svyaonymy.

Dis renudios
New Rreori
GH4631).
Recororn Rana The species is recorded from the
Coral Sea and Indonesia as well as trom (riggs L
(Western Australia). The new record extends tts known
range into temperate waters.

Western Australia (Albany. QM

Discretion

Small colonies of sexually immature upright
vooids (up to 3mm tall) jomed by stolons, are
epizooitic on Polvearpa flava found in sea grass
beds, The 4-lobed apertures are small and wart-
like, the test wrinkled around them, and covered
with adherent sand. Three folds are present on
each side. The branchial formula ig DL.
1(9)4(6)4(6)0EO. The stigmata are in 10 rows,
each crossed by a parastigmatic vessel. The gut
forms a Short rounded loop with the lang rectum
extending anteriorly to the base of the atrial
siphon, There are 12 broad stomach folds
expanding distally, The proximal ends ol the folds
on the inner side of the stomach terminate on
each side of the suture line, A long caecum is
curved in the gut loop which also encloses a small
endocarp. There are also Some oval lo elongate
endocarps scatiered on the body wall.

Remarks: The newly recorded specimens differ
from Lhose previously described in having a shorter
stomach with fewer folds, a longer gastric caecum
curved back into a U-shape, and sand adhering
to the test, These differences may be associated
with the small size and immature condition of the
material from Albany which, if correctly
assigned, represents 4 population at the southern
extreme of the range of this tropical species. The
only other species with upright zooids joined by
stolons, and 3 branchial folds per side are
Stoloniva truncata Kott, 1972 (with apertures in
transverse slit-like depressions, a pronounced
gastric spur. and long, narrow male follicles), .
nodula (Rott, 1985) (with a very short gastric
caecum), and §. al/uta Koti, 1985 (with more
internal, longitudinal branchial vessels than the

MEMOIRS OF THE QUEENSLAND MUSEUM

present species, a characteristic stomach with a
pronounced gastric spur, and 20 rows of stigmata
rather than the 10 10 12 of the present species).

Re-examination of the type specimens of
Amphicarpa clongata Kott, 1952 (AM YIS97
Y¥ 1599) showed that the long, male gonads referred
to by Kott (1952) are oval to elongate endocams:
and that the species is a junior synonym of
Stulonica redycta (Kott 1985).

Genus Polyzoa Lesson, 1831

Polyzoa exigua tsp.
(Figs 16-19)

Dish Rint Hom

Tyrer Lowatrry. Albany, Western Australia. epivavi-
tic on Polvearpa flava from sea grass beds (Pusidenia
“inuwxa and P. australis), coll, P, Hutchings January
1988, holotype QM GH4628, paratypes OM GH4629
30,

The species occurs with Molgula iicidafa and
Stifonica reducta, ind appears to be part of a Nourishing
sed fuss CaMmMunity made up of similar syzed Organisms.

Desc RIPTION

Zooids are smal! and dome-shaped, not more
than Smim in diameter and up to 2mm high. The
smooth-rimmed apertures on the upper, rounded
surface are on small, conical siphons, the branchial
aperture toward the anterior end of the upper
surface. and the atrial in the centre. Zooids are
partially or completely covered with adherent sand
particles. although the apertures are not econcealed.
A sphincter muscle which appears {rom the surface
as a White circle around each opening. helps to
distinguish the species from other similar ones in
the same habitat, Between sand grains the slightly
translucent but rather tough and wrinkled test is
prey to blue in these preserved and contracted
specimens. Short stolons radiate from the zoids.
although the zooids do nol appear to remain
connected to one another.

The body wall has a fine mesh of inner,
longitudinal and outer circular muscles. The duct
of the neural gland has a simple circular opening
in the V-shaped pertubercular area, The dorsal
lamina is moderately long. but the branchial sac
has a tong, deep curye around the ventral border
and there js a long retropharyngeal groove across
its posterior end,

There are 8 rows of stigmata and 3 internal
longitudinal vessels on each side. In the centre
of the branchial area the stigmata have the formula
E10,6-8,6-8,6DL. To accommodate the long
ventral curve of the branchial sac there are fewer
stigmata in the anterior and posterior rows and
the fifth row does not reach the dorsal mid-line.
Parastigmatic yessels are present.

THE AUSTRALIAN ASCIDIACEA |. SUPPLEMENT 281

Figs 13-21: Stolonica australis (QM GH4142) — 13, portion of colony; 14, internal organs. Stolonica reducta
(QM GH4631) — 15, gut loop. Polyzoa exigua n.sp. (holotype QM GH4628) — 16, external appearance;
17, internal organs; 18, gut loop; 19, mature gonad. Polyzoa nodosa n.sp. (QM GH4154) — 20, internal organs
on left; 21, testis follicle. (Scales: 13, 14 — 2mm; 15, 17 — 0.5mm; 16, 20 — Imm; 18, 19, 21 — 0.2mm).

282

The gut forms an almost simple, vertical loop
across the middle of the left body wall. The rather
short stomach, increasing in diameter toward its
pyloric end, is in the middle of the proximal limb
of the loop. The stomach has 12 broad folds and
a short, straight caecum that projects into the pole
of the gut loop. The anal border is bilabiate.

Gonads are arranged in a row around the ventral
curve of the right side of the body. They are not
all mature at once. Not more than 5 were found
in any one zooid, and these were irregularly
spaced. Thus, it is probable that gonads could
be more numerous. Gonads usually were absent
on the left side of the body, although a single
polycarp was found just anterior to the gut loop
in one specimen only. The gonads are hermaph-
roditic. The sac-like ovary has one or two large
eggs and 5 or 6 smaller ones, and it opens into
the atrial cavity by a short, broad duct with a
wide opening. The testis is circular and the straight
vas deferens crosses over the mesial surface of the
oviduct.

There is a long, narrow endocarp on each side
of the body.

Remarks: The absence of connecting stolons
between the zooids in this species is unusual,
although vegetative zooids develop, as usual, at
the end of the rather short but thick stolons. The
species is distinguished from Polyzoa violacea (see
Kott 1985) by its relatively few internal longitud-
inal branchial vessels, sandy test, short and straight
gastric caecum, and deeply curved branchial sac.

From its description, Polyzoa translucida Ritter
and Forsyth, 1917 (see Van Name 1945) from
California differs from the present species only
in its upright, stalked zooids and terminal
apertures. It is possible that this apparently close
resemblance is due to convergence rather a direct
phylogenetic relationship. Nevertheless, Polyzoa
is homogenous and appears monophyletic.

Polyzoa nodosa n.sp.
(Figs 20,21)
DisTRIBUTION
Tyre Locatiry; Price I., South Australia, coll. SAS
9.4.87, 15-20m, holotype SAM E2031, paratype QM
GH4154.

DeEscrRIPTION

Colonies consist of a tangle of fine branching
and anastomosing stalks that form a great, loose
mass apparently embedded in a sandy substrate.
Small (5mm diameter) spherical zooids, sometimes
sessile, but sometimes with up to 3 short stems,
are attached to the upper surface of this tangled
mass, forming a single, often compact, layer of
zooids. These probably form a mat on the surface

MEMOIRS OF THE QUEENSLAND MUSEUM

of the sea floor. Both zooids and stalks are covered
with a coating of sand. Zooids often are attached
to one another through the sand that adheres to
the test. The apertures are sessile, and sometimes
slightly depressed into the upper surface. Zooids
are occasionally laterally flattened but this is
probably an artefact of their preservation. In
preservative the linings of the siphons are orange,

The body wall adheres closely to the test.
Circular muscles surround each siphon, and
longitudinal muscles radiate from them, crossing
one another as they extend obliquely down the
body. The 24 branchial tentacles are of various
sizes. The dorsal lamina is wide and smooth-edged.
The dorsal tubercle has a simple, longitudinal slit.

The branchial sac has 4 internal longitudinal
vessels, no folds, and 8 to 10 rows of stigmata.
Usually each row is crossed by a parastigmatic
vessel, although in older zooids with 10 rows the
posterior 2 and the anterior rows do not have
them. About 7 stigmata are present in each mesh.

The oesophagus is short, opening into a fairly
long stomach that occupies the proximal half of
the ascending limb of the gut loop and has about
15 parallel folds in its wall. At the pyloric end
of the stomach there is a long gastric caecum curled
around in the gut loop. Three ligaments from the
outer curve of the caecum attach it to the inner
curve of the intestine. The intestinal loop is narrow
and the rectum forms a U-shaped secondary loop
with the descending limb of the primary loop. The
anal border is smooth and bilabiate. The whole
gut loop is in the posterior half of the left side
of the body.

Hermaphroditic gonads are in a single row each
side of the endostyle, 5 or 6 on the left and 6
to 8 on the right. The small, almost spherical
ovaries contain 6 to 8 eggs, and have a short,
wide oviduct. The single fan-shaped male follicle
beneath each ovary has a short duct curving out
to the side of the oviducal opening. The male
follicle is deeply divided into about 7, sometimes
branched, lobes.

Remarks: This species is distinguished from the
tropical Polyzoa violacea by its relatively few,
internal, longitudinal branchial vessels and its
sandy test. A long gastric caecum does occur in
Polyzoa violacea, but the stomach of the present
species is longer and has more folds.

Polyzoa nodosa is, like P. exigua (see above),
sandy. However, unlike P. exigua, it has conspic-
uous sandy stolons, spherical zooids with 4
internal longitudinal vessels, a long curled gastric
caecum, and a long stomach,

Symplegma arenosa Kott, 1972 (see Kott 1985)
has sandy zooids connected by basal stolons, but,

THE AUSTRALIAN ASCIDIACELA |. SUPPLEMEN|

although assigned to the genus Svmplegmia. its
gonads are not known. Its holotype has been re-
examined, Its upright. sessile zooids with a
pronounced ierminal depression, more numerous
(15) rows of stigmata, short horizontal intestinal
loop, long rectum, short stomach and short,
straight gastric caecum distinguish Ww from the
present species,

Genus Metandrocarpa Michaelsen. 1904

Metandrocarpa miniscula Kott, 1985
(Figs 22,23)
Mefandrucarpa miniscula Kott, 1985, p. 254

Dist Riau Trios

New Recoros- Queensland (Moreton Bay, Pt
Lookout, QM GH4264 GH4266).

Like the syntypes. the newly recorded specimens were
taken in the intertidal zone —- in crevices in rocky
quicrops on a sandy beach. They were found closely
associated with a sand-adapted fauna thal included
Peruphora sabulosa n.sp. a sandy undescribed 4 plidiur|
sp, algac and coelenterates.

Recorbro Rawxce Previously known from a single
record at Misston Beach, northern Queensland.

DescriPTion

Spherical. sessile zooids about 4mm diameter
to small club-shuped ones which narrow poste-
riorly to single stems about the same Jength as
the zooids. These are attached to basal stolons.
Colonies form a mat over ihe substrate or they
fill crevices between the associated fauna so that
aggregates of diverse taxa have sa level, sandy
surface.

The apertures of zooids are obscured by
adhering sand, Internally, they are.on short comical
siphons directed away from one another. Circular
muscles surround each siphon and the body.
Longitudinal muscles radiate [rom each siphon.
The dorsal lamina ts a wide membrane. There are
4 internal longitudinal vessels in the branchial sac,
and stigmata, in & rows, have the formula
£6,6,4.4,5DL. The simple gut loop hes in the
dorsal half of the body and is more or less vertically
oriented. The descending limb, opening at the hase
of the atrial siphon, is Jonger than the ascending
one. The oesophagus is short, and its opening from
the branchial sac is about halfway down the body.
The short stomach with § to 12 broad folds
occupies only a small part of the ascending limb
of the gut loop. A short caecum increases in length
with increasing numbers of stamach folds it
is Straight in zooids with § stomach folds and
curved in those with 12.

Usually 5 long. vertically-oriented. oval male
follicles ure in the posterior curve of the body

283

on the right side, Their short ducts are at the
anterior end of each follicle. A single male follicle
is on the left side of the bady ventral to the gut
loop, A variable number (up to 3 on cach side)
af small, sac-like, 3-.or 4-egy ovaries are present
just posterior to the male follicles on bath sides
of the body. Many of the zouids that were
examined had developing embryos and larvae
lying tree in the peribranchial cavity (colonies
collected in June). The larval trunk ts 0.5mm long.
and has the same structure as larvae [rom the
syntype 7ooids.

There are a few round, flat-topped endocurps
on the body wall.

Remarks. The newly tecarded zovids have
more numerous stomach folds than the smaller
syntypes, and they have a gastric caceum,
Howeyer, the gut loop has the same orientation
in both specimen lots, the branchial sacs are the
same, the gonads (which vary in number in hoth)
are similarly arranged and the specimens are
sufficiently alike to be considered conspécilic

The 3 Metandracarpa spp. recorded from
Australia are all sandy and resemble one another,
Although the gonads of M. medica Kott, 1972 are
not known, the 2 other species have large, elongate
male follicles in the postero-ventral part of the
body, and a yarable number of sac-like ovarics,
rather irregulacly arranged, posterior and yentral
to the male folheles. The Western Australian
Metandrocarpa ogitata Kott, 1985 is larger and
better developed than either M2 indica [rom
Western and South Australia or the present
species. The Jast two species, are similar in many
respects, both having 4 internal longitudinal
branchial vessels and 9 (or 10), und & rows of
Stigmata, respectively, The key character used by
Kott (1985) to distinguish these two species, viz
the absence of the gastric caecum, is now invalid,
since the caecum is now known to be present in
both species, although it is longer in M, inelica
than in M. miniseula. Metandrocarpa indica cas
be distinguished from M_ miniscula by its sessile
and flattened, rather than stalked and upright.
rooids, and its long, pointed, atrial siphon,

Genus Botryllocarpa Hartniever, 1911

Botryllocarpa elongata 1.sp,
yoy 4.9
DisrRiRU TION (Pigs 24-26)

Tyrr Locatiny: Phillip 1. Bass Strain. Victoria. in
caves. coll, W, Tiegs, November 1956, holotype AM
¥2122,

Disctertian

The holotype colony i narrow, almost elite

drical. and branches along @ stem of seaweed, The

284

test is glassy and transparent. Zooids, arranged
in 2 rows, one along each longitudinal border of
the colony have their longitudinal axes parallel
to one another. The terminal branchial apertures
all face the outer edge of the colony, and the atrial
apertures, which are near the posterior end of the
horizontal zooids, face toward the centre of the
colony. Large, spherical, terminal ampullae of the
test vessels are scattered in the test between the
zooids.

Zooids are only about 2mm long. The margins
of both branchial and atrial apertures appear to
be smooth. The body wall is very delicate and
the organs embedded in it are readily dislodged.
A narrow ring of fine muscles surrounds each
aperture, and fine, inconspicuous, longitudinal
muscles radiate only a short distance from each
aperture. Of about 16 branchial tentacles of
various sizes found just inside the branchial
aperture, 4 are quite long. The dorsal lamina is
long and smooth-edged but narrow. Anteriorly
it flattens out and extends across the prebranchial
area to the tentacular ring as a fairly broad raised
area with the simple opening of the neural duct
in the centre. The peripharyngeal bands terminate
on each side of this raised area.

Three longitudinal vessels on each side of the
body cross 9 rows of stigmata, which have the
formula DL10,6,5,4E. The oesophagus is short,
bending ventrally and anteriorly from the
oesophageal opening at the posterior end of the
branchial sac to open into a barrel-shaped
stomach. There are 8 broad, parallel, longitudinal,
gastric folds and a short, straight pyloric caecum.
The stomach occupies the proximal half to two-
thirds of the ascending limb of the gut loop and
is longitudinally oriented. The intestine curves
around laterally and posteriorly to lie outside and
close to the ascending limb of the gut loop. The
rectum is relatively short and curves around the
outside of the oesophagus onto the dorsal surface
to open near the atrial aperture. The anal border
is smooth and bilabiate. The gut loop occupies
the posterior half of the left side of the body.

A single testis on each side of the body lies
anterior to the gut loop on the left and halfway
down the body on the right. Each consists of a
single, fan-shaped to circular follicle deeply
divided into 3 to 5 tapering lobes. A short vas

MEMOIRS OF THE QUEENSLAND MUSEUM

deferens opens directly into the atrial cavity.
Ovaries are not present in this colony.

Remarks: The type species, Boiryvllocarpa
viridis (Pizon, 1908) from Indonesia, was assigned
originally to Protobotryllus (Botryllidae). Hart-
meyer (1911) erected Botry/locarpa in the
Polyzoinae to accommodate it, believing that the
Botryllinae, with their cloacal systems, were
distinct from the separately opening Polyzoinae.
Since then, Kott (1985) questioned whether the
genus was distinct from Chorizocarpa Michaelsen,
1904, which also has 3 internal longitudinal
branchial vessels but dioecious gonads, the male
and female on opposite sides of the body.

Tokioka (1972) believed the genus to be a
synonym of Symplegma, despite the differences
in the number of internal longitudinal branchial
vessels. He reported that crowded specimens of
Syniplegma do show variations in the number of
these vessels, sometimes having only 3 rather than
the characteristic 4. However, this is apparently
an abnormality impressed by the environment
rather than a genetic difference. Other differences
between the genera reinforce the difference in the
branchial sac. Musculature of Symplegma spp.
consists of an inner layer of longitudinal fibres
and an outer layer of circular fibres, and the
apertures become frilled when contracted. In the
present genus the musculature is less developed
and the apertures remain smooth-rimmed even
when contracted. Further, the test of Symplegma
is delicate and easily torn while that of the present
genus is firm and gelatinous, and Symplegma spp.
appear to be more prolific vegetatively with zooids
usually being crowded in the test.

Botryllocarpa and Chorizocarpa are not readily
separated, for apart from differences in distribu-
tion of male and female gonads, both genera have
similar colonies, the same firm, glassy test, 3
internal, longitudinal branchial vessels on each
side, rather limited musculature, plain-rimmed
apertures, a similar number of rows of stigmata
and stigmata per row, and both appear to have
the same rate of replication. Nevertheless, in the
three known species of Chorizocarpa (see Kott
1985) the male gonad is on the left and the female
on the right, while Borryllocarpa has both male
and female gonads on both sides of the body. The
two genera are therefore regarded here as distinct.

Figs 22-28: Metandrocarpa miniscula (QM GH4264) — 22, right and left sides of the body from outside; 23,
gut and gonads from inside body wall, Borryllocarpa elongata n,sp. (holotype AM Y2122) — 24, portion
of colony; 25, zooid from ventral surface; 26, gut loop from left side. Borrvllus stewartensis (QM GH4262)

27, body removed from test from left side. Botryllus tuberatus (QM GH4274) — 28, body removed from
test from left side. (Scales: 22, 23 — Imm; 24 — 2mm, 25-28 — 0.5mm).

285

THE AUSTRALIAN ASCIDIACEA |. SUPPLEMENT

286

Botryllocarpa elongata n.sp. and the type
Botryllocarpa viridis (Pizon, 1908) have the same
4 large branchial tentacles, 9 rows of stigmata and
a longitudinally oriented stomach and gut loop.
However, in Pizon’s species the atrial aperture is
opposite the third row of stigmata rather than
in the posterior half of the body, and, although
the rectum is longer than in the present species,
the descending limb of the gut loop is shorter.
The longer rectum appears to be associated with
the anterior position of the atrial aperture about
one-third of the body length from the branchial
aperture, rather than in the posterior end of the
body as it is in the present species. In addition
to the circular muscles around the apertures B.
viridis has longitudinal bands between the
branchial and atrial apertures that are not present
in the Australian species; the male gonad has two
separate follicles in B. viridis but only one in B.
elongata, and there are only 8 stomach folds in
the latter species, but 11 to 14 in B. viridis.

There are only 3 records of the genus Borryl-
locarpa, viz. the type from Indonesia; Botryllo-
carpa pizoni (Tokioka, 1972) from the Pacific
coast of Costa Rica (which despite its geographic
separation is apparently a junior synonym of the
type), and the present species.

Subfamily BOTRYLLINAE Adams and Adams,
1858

Genus Botryllus Gaertner, 1774

Botryllus stewartensis Brewin, 1958
(Fig. 27)
Botryllus stewartensis Brewin, 1958, p. 444. Kott 1985,
p. 269 and synonymy.

Dis TRIBUTION

New Recorps: Western Australia (Albany, QM
GH4632). New South Wales (Port Hacking, AM Y2153).
Queensland (Moreton Bay, QM GH4262). Western
Australian specimens are epizooitic on Polycarpa flava
from sea grass ( Posidonia sinuosa and P. australis), those
from Queensland are from about 6m off Dunwich, and
New South Wales records are from Little Turriel Point
from 20m,

Recorpep Rance: South Australia (Spencer Gulf),
Victoria (Port Phillip Bay and Ninety Mile Beach), New
South Wales (Port Kembla and Port Stephens), and
New Zealand (Stewart and South Is.).

DESCRIPTION

The newly recorded material from eastern
Australia forms compact colonies consisting of
sandy, upright stalks up to 2cm high and 0.5cm
diameter with a flat terminal surface onto which
the zooids open around a central cloacal aperture.
Adjacent stalks adhere to one another through

MEMOIRS OF THE QUEENSLAND MUSEUM

their attached sandy coating. The stalks compris-
ing one colony are all of even height and their
flat terminal surface, with the cyclamen pigmen-
tation of the zooids apparent through the sand,
appear from the surface as a compact mosaic.
Some stalks are wider, flat in section, and
subdivided terminally into zooid bearing heads of
the usual diameter.

The zooids have 12 rows of stigmata with the
formula E5,3,3,4,DL4,2,3,4E. The horizontal gut
loop is slightly posterior to the branchial sac. There
are 12 broad folds in the wall of the short, barrel-
shaped stomach, and a relatively short caecum
curves into the gut loop. Larvae are present in
the peribranchial cavity of Moreton Bay specimens
collected in August. There is a large, lobed testis
on each side — just anterior to the gut loop on
the left.

Colonies from sea grass beds at Albany are
small, cushion-like lobes with relatively short
stalks and immature zooids.

Remarks: Zooids from both newly recorded
specimen lots from eastern Australia differ from
South Australian material in having a larger
interval between the endostyle and the ventral fold
on each side, 12 (instead of 10) stomach folds,
and a more deeply subdivided testis. These do not
appear to be more than population differences.

Botryllus tuberatus Ritter and Forsyth, 1917
(Fig. 28)
Botryllus tuberatus Ritter and Forsyth, 1917, p. 461.
Kott, 1985, p. 271 and synonymy.

DIsTRIBUTION

New Recorps: Queensland (Moreton Bay, QM
GH4274),

Recorpbrep Rance: The species is known from
Cockburn Sound (Western Australia) and from Hervey
Bay northwards to Lizard I. (Queensland) as well as
from the western and eastern Pacific, and Japan. It is
not impossible that convergence and simplification in
these small zooids has obscured species differences, and
that the eastern and western Pacific populations are not
conspecific.

DESCRIPTION

Living specimens have well-formed orange
zooids 1.6mm long, arranged in circular systems
in a colourless test. In preservative the zooids are
dark. There are about 12 tentacles of various sizes.
The stigmata are long, and are arranged in 4
regular rows with the formula DL 3,3,3,5E. The
slightly curved, horizontal gut loop is in the
posterior end of the body. The barrel-shaped
stomach, with 8 broad folds and a curved caecum
with a terminal bulb, occupies the middle of the
ascending limb of the gut loop.

THE AUSTRALIAN ASCIDIACEA 1. SUPPLEMENT 287

Remarks: The newly recorded specimen has
larger zooids and more branchial tentacles than
previously recorded for this species. The stigmata
are long and rectangular, and the rows of stigmata
are regular, reaching from the endostyle to the
dorsal lamina without a shorter interstitial row
being present ventrally. The stomach is longer and
more barrel-shaped, and has slightly fewer folds
than the 10 previously recorded. Nevertheless,
zooids are in regular circular systems in a clear
test, the atrial aperture is small and circular and
produced dorsally on the end of a conically
expanded dorsal surface, there are the same
numbers of stigmata in each row, and the gastric
caecum is identical with that previously described.
The differences between the present colony from
Moreton Bay and the previously described
specimens from the tropics could be associated
with its better developed zooids.

Family PYURIDAE Hartmeyer, 1908
Genus Pyura Molina, 1782

Pyura arenosa (Herdman, 1882)

Cynthia arenosa Herdman, 1882, p. 140.
Pyura arenosa: Kott, 1985, p. 289 and synonymy.

DistTRIBUTION

New Recorp: Victoria (Bass Strait, MV F54197). The
record is from 52m.

Recorpep RANGE; The species has been recorded
from the eastern coast of Australia from Mission Beach
to Bowen, from Houtman’s Abrolhos in Western
Australia and from Indonesia, Torres Strait and the
Arafura Sea.

This is the first record of this species from temperate
waters.

DESCRIPTION

The new record is of a single spherical, sandy
specimen Icm long. The characteristic flattened,
leaf-like overlapping spines line the siphons and
continue onto their outer surfaces and over the
anterior half of the test, where they are obscured
by adherent sand.

Pyura rapaformis n.sp.
(Figs 31,32)
DISTRIBUTION
Type Locatiry: Western Australia, Cottesloe, on
upper surface of reef near pylon, 2m, coll. L. Marsh
30.12.86, holotype WAM 190.87, paratypes WAM 27.87,
QM GH4309,

DESCRIPTION

Individuals are turnip-shaped, more or less flat
on their upper surface which is circular and about
3cm in diameter. The 3cm long body tapers to
a long (7cm), narrow (0.5cm), flattened posterior

root that terminates in short branches. Crowded
vertical papillae (up to 1.5mm long), some
cylindrical and some flattened lamellae, project
from the surface of the test and these and the
test between them are covered in sand. Individuals
adhere to one another through the sand that covers
them, and through the vertical sand-covered
projections that interdigitate with those of
adjacent individuals. The upper surfaces of the
individuals in an aggregate together form an even
platform. Individuals in the aggregate adhere to
one another along their length, and as they taper
posteriorly their basal root-like processes on the
under surface of the aggregate are relatively close
together.

Both apertures are close together on short 4-
lobed siphons in the centre of the upper surface.
The lobes on the facing sides of each siphon are
larger than the outside ones so that the openings
are directed away from one another. The lobes
of the apertures are also covered with projecting
papillae, similar to those on the remainder of the
body, and these and the sand that adheres to them
obscure the openings. Papillae are not present on
the root where the surface test is densely
impregnated with sand. The test itself is relatively
thin and transparent, its strength conferred by the
adhering sand, projecting papillae, and the
adhering test of adjacent individuals. The internal
test of the stalk is soft and pierced by 2 wide canals.

Siphons are lined with pointed, overlapping
hollow spines, Imm long, with a long slightly
expanded base and a long but constricted opening.
The point extends anteriorly in line with the base
and is only very slightly curved. The posterior end
of the base terminates in 4 rounded swellings.
These spines are light green in preservative.

The body wall has a thin, outer layer of circular
muscle fibres which are particularly crowded on
the anterior half of the body. Internal longitudinal
bands terminate in short branches at the posterior
end of the body on the right and just anterior
to the gut loop on the left. The body comes to
a point posteriorly and a thin projection from it
extends into the posterior root. There are about
20 long, sickle-shaped tentacles of various sizes,
branched 3 times. The first-order branches are
relatively long and give the tentacles a feather-
like appearance. The prominent dorsal tubercle
has a deep slit with each horn spiralling inwards
about twice, and the open interval directed
forwards. The peritubercular area is relatively
shallow.

There are 6 wide, overlapping branchial folds
on each side. The branchial formula is
E2(7)3(16)3(19)3(22)3(20)2(22)IDL. Eight stig-

288

Mata per mesh are present in the centre of the
branchial sac. The dorsal lamina, consisting of
pointed languets. is long, the oesophageal opening
being at the posterior end of the branchial sac.

The gently curved gut loop encloses about I)
pairs of large polycarp sacs. The liver is large,
branching otf the ascending limb about halfway
along its length. There is only a single accessory
diverticulum proximal to the main liver divertic-
ulum. The anal border is plain. There are
numerous, branched and lobed endocarps on both
gut and gonads.

Remarks: The specics is. possibly most closely
related to Pyura faxymanensiy from the south-
eastern corner of Australia. The position of the
apertures (close together on the upper surface) the
siphonal spines, the circular body musculature.
the feathery branchial tentacles, the double spiral
opening of the neural gland, the large overlapping
folds of the branchial sac, the course of the gut,
and the endocarps on gut loop and gonad sacs
areallsimilarin 2 rasmranensis and P. rapaferniis,
However, the aggregates of P. laymanensiy are
irregular. and do not torm an eyen platform as
do aggregates of the present species. The
Tasmanian species has 4 more protuberant dorsal
tubercle, and has more internal longitudinal
vessels in the interspuces. However, the principal
distinclions between the two species are found in
the test. The test of ?. lusmiariensix is sandy with
wrinkles and ridges but lacks the projecting
papillae of the present species, and it bas a short
stem or tufts of posterior, root-like extensions (hat
hold the aggregates together, rather than the
single. long, posterior root of the present species,

Pyura tasmanensis Kott, 1985
Pura tasinanensis Kou, 1985, p33)

Disre isu iies

New Recorp: New South Wales {Bermagui, AM
Y2174). The new record is fram ahaut 300m,

Rreorori Rance Previous records are trom the
eastern coast of Tasmania, mostly storm debris collected
from beaches. but one specimen lotis Known trom 154m
The new record suggests a Wider tange to the qarth
in deeper Waters of the eastern Australian continental
abel.

Genus Ctenicella Lacaze-Duthiers, 1877

Ctenicella antipoda Kou, 1972
(Fig. 29)
Cremieella anripada Korte W72a. p. 44: LORS. p. 339.
Dis nee ton

New Ricuis South Australia (Tipara Reel, OM
‘i HARAY),

MEMOIRS OF THE QUEENSLAND MUSEUM

Previousiy Rrearguro: St Vineent and Spenver
Gulls (including Tipara Reef) to 20m.

Description

The specimen is large, slightly laterally flattened,
and deeper than its height. The rim of test that
surrounds the upper surface is discontinuous,
made up of a number of upright sandy ridges.
Irregular sandy lobes are also present on the upper
surface between the apertures, obscuring them.
Despite these irregularities of the outer surface
of the sandy test, the internal cavity is regularly
oval with a smooth hning.

A band of rather flat, asymmetrical, hollow.
conical spines surround the outer part of each
siphon lining. The free pointed tip of each spine
is Short, the base Jong and open, and the outer
surface af the cone (facing the lumen of the siphon)
Jong. and flattened and scale-like posteriorly.

‘The gut is large, the rectum swollen with faecal
material, as is usual for this species, and the sessile
liver has ihe usual crowded paralle) tubules.
embedded in the body wall over the pyloric region
of the gut. The gonad is degenerate, embedded
in the body wall dorsal to the gut loop, The
specimen appears lo be senescent.

Remarks: Owing to the sandy ridges around
the upper surface of this specimen it resembles
Pyura stolonifera, It especially resembles the
rather squat, sandy, €stuarine and the sandy,
tuberculate, juvenile forms of P. sr0lontfera.
Further, the sandy lobes between the apertures
superficially resemble the siphons of the latter
species. However, in P, stolonifera the rim around
the upper surlace is u fold rather than a solid
ridge of test; and the body wall of the ‘zooid is
similarly folded, the anterior surface, including the
siphons, being depressed into the rest of the body.
In C. ahtipoda the body has a smooth oval outline
when removed from the test.

The siphonal spines. which previously have been
overlooked in this species. also resemble those of
Prura stolonifera (see Fig, 30) as well as those
of PF. spinasa and P. spinifera (see Kott 1985).
tlowever, the free pointed tip of the spines of the
present Species is shartec than in any other species.

Genus Halocynthia Verrill and Rathburn, 1879
Halocynthia papillosa (Linnveus, 1767)

Ascidia papillosa Linneaus, (267, p. 1087
alow withia papillasa: Rov, 1945, p. 344-and synonyey,
Das) eerie 1 ccty

Nrw Reoort New South Wales (Ehzabeth Reet.
1Se°04'T 29°57'S, about S00km FE. of Grafton, AM
Y2I41), The single specimen was taken from [Om in
the Haguon of this isolated coral reef,

THE AUSTRALIAN ASCIDIACEA 1, SUPPLEMENT

Recorpep Rance: Atlantic coast of France, Medi-
terranean, Queensland (Heron I,).

REMARKS:

The newly recorded specimen is identical with
that previously recorded from Heron I. and with
the specimens from the northern hemisphere. The
two records from well separated coralline locations
off eastern Australia cannot be reconciled with
the previously recorded range of this species.

Genus Microcosmus Heller, 1877

Microcosmus curvus Tokioka, 1954
(Figs 33-35)
Microcosmus curvus Tokioka, 1954, p. 263; 1967, p.
215. Renganathan, 1983, p. 929,
Microcosmus exasperatus: Monniot and Monniot, 1987,
p. 125 (part, Figs 50c,e).

DisTRIBUTION

New Recorp: Queensland (Heron I., QM GH3814).

Recorpep Rance: Palau Is., Marianas Is., Wake L.,
Tokara Is, India (Gulf of Mannar). The synonymy of
specimens assigned to M. exasperatus by Monniot and
Monniot (1987) extends the known range of M. curvus
to Tahiti.

Description

The newly recorded specimen is 2cm high and
1.2cm wide. The branchial aperture is terminal,
directed downwards, and the atrial aperture, from
the antero-dorsal surface, is directed obliquely
upwards. The posterior two-thirds of the body was
buried in coralline sand and lacked pigment.
However, the anterior one-third projected from
the substrate and was, in life, a red-brown colour.
Irregular projections of the surface are present on
the anterior part of the body. There are white
stripes down the outside of the siphons. The test
is tough and leathery.

The siphonal lining has minute, overlapping,
flattened, pointed spines not more than 0,02 to
0.03mm long. The posterior end of the base of
the spine flares up slightly, rather than being
turned under into a hook as in Microcosmus
exasperatus (see Kott 1985). Spines near the outer
part of the siphon are shorter than those at the
base and are less pointed, sometimes having almost
rounded tips. The body wall is strong and
muscular. The branchial tentacles are bushy. The
opening of the neural gland, on the dorsal tubercle,
forms a single coil about one and a half times
in aclockwise direction from the centre. The neural
ganglion is long, extending from beneath the
dorsal tubercle to the base of the atrial siphon.
There are small, finger-like papillae projecting
from the peripharyngeal band.

There are 6 conspicuous branchial folds on each

289

side of the body and a seventh rudimentary one
on the left nearest to the endostyle. Internal
longitudinal vessels have the formula
E1(3)1(8)2(10)2(12)2(11)2(11) 1 DL. There are 4 to
6 stigmata per mesh.

The oesophagus is moderately long and opens
into an expanded pyloric region with parallel liver
lamellae in its wall. The lamellae in the proximal
part of the pyloric region are papillated. The gut
loop is open at the pole, and is slightly curved
around the posterior border of the body. The anal
border is smooth and bilabiate.

The left gonad crosses the descending limb of
the gut loop. The right gonad is in the postero-
ventral quarter of the right side. Both gonads are
slightly lobed at their broad proximal ends, and
the narrower distal ends curves up parallel to the
proximal end to form a deep U. The gonoducts
are directed anteriorly — toward the branchial
rather than the atrial apertures, Three or 4
scattered groups of small, pear-shaped male
follicles are closely applied to the sides or mesial
surface of each ovarian tube.

A few small endocarps are on the gut loop.

RemMARKs: There is, in this species, some
variation in the presence of tubercles on the
anterior part of the test, in the number and
direction of coils of the opening of the neural gland
and in the curves of the gonads (see Tokioka 1967),
Nevertheless, the species is well characterised and
is distinguished readily from others in the genus.
Microcosmus curvus is possibly most closely
related to M. madagascariensis, both having entire
gonads with the left one sometimes crossing the
gut, and similarly shaped siphonal spines.
However, the present species is distinguished from
M. madagascariensis by its smaller siphonal
spines, rudimentary seventh fold usually present
only on the left side, undulating and curving
gonads with the gonoducts directed anteriorly,
small pyriform male follicles on the sides and
upper surface of the ovary, shallow curve of the
gut loop, long neural ganglion, and usually the
coiling of only a single horn of the opening of
the neural gland.

The synonymy of this species with M. exaspe-
ratus suggested by Monniot and Monniot (1987)
is invalid, M. exasperatus differing in many
characters, most noticeably in the longer siphonal
spines with a basal hook, divided gonads,
orientation of its gonoducts toward the atrial
aperture, and double spiral coil of the opening
of the neural gland. Some of the specimens from
Tahiti (Monniot and Monniot 1987, figs 50C and
E) are almost certainly M. curvus, having
anteriorly directed gonoducts. Other specimens

290 MEMOIRS OF THE QUEENSLAND MUSEUM

THE AUSTRALIAN ASCIDIACEA 1. SUPPLEMENT

(see Monniot and Monniot 1987, figs 50A, B and
D) have their gonoducts directed toward the atrial
aperture, and probably are specimens of M.
exasperatus. However, without information on the
siphonal armature a definitive identification of
these specimens is not possible.

The specimens described by Tokioka (1967)
from Wake I. contained viviparous larvae. This
is entirely consistent with the orientation of the
gonoducts. Viviparity has not previously been
reported in this genus.

Microcosmus madagascariensis Michaelsen, 1918

Microcosmus madagascariensis Michaelsen, 1918, p. 20.
Kott, 1985, p. 351 and synonymy.

DistTRIBUTION

New Recorvs: Queensland (Moreton Bay, QM
GH3883). The newly recorded specimen is from 6m

RecorDeD RaAnGe: The species is known from
Western Australia (Broome and Albany) and from
Malagasy. The new record from Moreton Bay, in
extending the previously known range in the Indian
Ocean into the Western Pacific, indicates that the species
has a tropical Indo-West Pacific range. However, there
is no indication yet that it extends around the temperate
southern coast of Australia as the pan-tropical species
Microcosmus exasperatus and M. helleri are known to
do (Kott 1985).

DESCRIPTION

The newly recorded specimen is almost spherical
and about 2cm in diameter. The apertures are on
short, only slightly protruding, naked siphons.
However, the remainder of the tough, hard,
relatively thin, smooth test has a dense coat of
sand adhering to it. The body wall is muscular.
The flattened, pointed siphonal spines, 0.1mm
long, have a long, open base with its narrow
posterior border flaring up slightly. Both horns
of the opening of the neural gland spiral inwards
once only. The neural ganglion is half the length
of the dorsal lamina. There are 8 branchial folds
on each side of the body. The gut loop is long
and narrow, curving around the postero-ventral
curve of the body and reaching at least two-thirds
of the distance up the ventral border of the body,
Broad gonads with short branches or lobes
projecting from each side are deeply embedded
in endocarp-like thickening of the body wall. The
testis follicles are long and branched, lying in a
layer beneath each ovary and projecting out into
the body wall around the sides of the ovary.

291

Remarks: The specimen is smaller than the ones
previously recorded from Australia, it has 8 rather
than 7 branchial folds, and its gonads are not so
conspicuously branched. Nevertheless it has the
characteristic long, flattened siphonal spines, long
gut loop, endocarps on the gut and endocarp-like
thickenings of the body wall enclosing the gonads.
Its long, branched, male follicles beneath the ovary
and spreading out around the sides are unusual
for this genus, although similar male follicles do
occur in Microcosmus planus and M. stoloniferus
(see Kott 1985).

Microcosmus planus Kott, 1975

Microcosmus planus Kott, 1975, p. 15; 1985, p. 353.

DisTRIBUTION

New Recorp: Victoria (Bass Strait, MV F54211). The
specimen was taken with Molgula mollis on a sandy
substrate.

RecorbeD RANGE: The species previously was known
from a single location at 3lm, Elliston Bay, Great
Australian Bight,

DESCRIPTION

The newly recorded specimen is 1.5cm in
diameter — including the sandy coating. It has
the same laterally flattened circular shape with
a thick ventral keel, as well as the other
morphological characters of the type material
including the sessile apertures, siphonal spines,
long dorsal lamina, and sinuous gonads with the
left one outside the gut loop. The long, branched,
male follicles are beneath and projecting out
around the sides of the ovary. It differs from
previously recorded specimens in having 8 rather
than 7 branchial folds on the left side, although
only 7 folds are present on the right.

Microcosmus stoloniferus Kott, 1952

Microcosmus stoloniferus Kott, 1952, p. 291; 1985, p.
359 and synonymy.

DistRIBUTION
New Recorps: Torres Strait (QM GH4833-6).
Recorpep RAnGe: Formerly recorded from South
Australia, Tasmania and through Bass Strait and north
to the vicinity of Lizard I. The new record extends the
known range of this species into the high tropics,

Remarks: The newly recorded specimens
(dredged from the sea floor) are numerous but
small, characteristically sandy, usually tapering to
a point posteriorly, but some with the posterior

Figs 29-30: Crenicella antipoda (QM GH4849) — 29, siphonal spines. Pyura stolonifera — 30a, siphonal spines
from juvenile, Arrawara, NSW (QM GH2246); 30b,c, siphonal spines from large coastal specimens, Albany,
WA and Tweed River, NSW (QM GH4646 GH4892). (Scales: 29,30 — 0.05mm).

test produced into thin, Short, sand-covered, root-
like projections. The apertures are in a narrow
depression in the flattened upper surface,

It is probable that this species will be found
to occur in Indonesian waters.

Genus Hartmeyeria Ritter, 1913
Hartmeyeria formosa (Herdman, 1482)

Crathta formosa Herdman, 1882, p. 139.
Hartineveria formosa: Kott, 1985, p, 363 and synonymy,

Dis rie ron

Nrw Rreornm: Queensland (Swain Reefs, AM Y2179),
Ihe species was taken from 76m.

Recorpep Ranar The new record extends the
known range of this species [rom Australiam coustal
waters between Torres Strait and Bass Strait out onto
the edge of the continental shelf about 200km ullshure.
ht will probably be found to occur over the whole of
the Australian Continental Shell.

Genus Molgula Forbes, [848

Molgula calvata Sluiter, 1904
(Fig. 36)
Molgula valvata Sluiter, 1904, p. 116. Kott, 1985, p.
369 und synonymy,

DisTRIBE Fie

New Recoros- Western Australia (Albany. QM
GH4641). South Australia (Yorke Peninsula, SAM
E2088). Victona (Western Port, MV F53301 F53304
F53317 F54205).

Recororen Rance The species has been recorded
trom Indonesia. the Philippines, Triggs L and Albany
in Western Australia, and Innisfail, Gladstone, Noosa
vod northern New South Wales on the eastern coast
of Australia, The records are all from shallaw depths;
the new records for Western Port at 1im are the deepest
yet recorded for this species. The species is taken always
from sandy substrates. and very lkely wall be found
to oceur all along the castern and western Australian
coasts in similar habitats.

Desc rirtion

The newly recorded specimens have the
characteristics previously reported for this species.
viz. delicate test covered with long, line, hair
like projections to which sand adheres, 2 internal
longitudinal branchial vessels on the ventral side
of each fold, the left gonad enclosed in the deep
U-shaped curve of the narrow gut loop, and
numerous short vas deferens openings along the
centre of each ovary. The opening of the neural
gland is a reverse C-shape, although in one
specimen the lower horn is turned posteriorly. The
parietal border of the opening of the rather long
oviduct is bent inwards over the end of the tube
to create a crescent shaped aperture directed

MEMOIRS OF THE QUEENSLAND MUSEUM

ventrally. The newly recorded specimen collected
in November, has a single larva in the peribran-
chial cavity.

Molgula incidata Kott, 1985
(Pigs. 37 39)
Moleula invidata Kou, 1985, p. 377,

DISTRIBUTION

New Reecokos Western Australia (Albany, QM
GH4033 4). Epizvooites on Polvearpa flava from sea
erass (Posidoria yinuosa) beds

Recokbep Rayo The species formerly was known
only from Heron L., Innisfail (Queensland) and Norfolk
lL. New records suggest that this small, inconspicuous
species has a wide range around the Australian coast,
and very likely it is more common than the present
records suggest. With one exception (see Kon 1485),
the specimens recorded are epibionis. However. as Kott
(1985) observed, this does not reflect an obligate habitat
but rather the fact that these small individuals wre not
readily observed in the field.

Deseristion

Zooids are small (4mm diameter) dames with
a thin test, brittle with embedded sand. ‘The
apertures are sessile, about one third of the body
length apart in the middle of the upper surface.
Circular muscles are around each aperture. and
short longitudinal muscles radiate from euch side
ol the siphons. About [2 branchial tentacles of
various sizes have moderately long pinnate
branches. A single circular opening of the neural
duct is to the right of along neural ganglion. Seyen
low, branchial folds are on each side of the body,
A wide, internal longitudinal vessel is on the
ventral side of each fold. another is along the edge,
and there are two, fine, internal longitudinal
vessels on the dorsal side of all folds except the
first and the seventh. The ventral fold contains
9 infundibula, each with asingle, coiled stizmatum
in the centre surrounded by two concentric. curved
stigmata in each quarter. In the second to sixth
folds there are 7 similar infundibula, The folds
are represented mainly by the internal longitudinal
vessels which project aboye the shallow infundib-
ula on the almost flat branchial wall. The gut loop
is long and narrow, and slightly open at the pole.
Itextends almost halfway around the Ventral curve
of the-body. The gastric folds are lobed and
oblique. The kidney is short. almost rectangular
and contains a hard concretion.

The left gonad is in the curve of the gut lnop
and the right one is antero-dorsul to the kidney.
The ovary is a round sac With a $hort, broad
oviduct directed postero-ventrally. There are
about 5 small, male follicles situated uround the
proximal curve of the oyary. Their ducts converge

THE AUSTRALIAN ASCIDIACEA |. SUPPLEMENT

293

Figs 31-40: Pvura rapaformis n.sp. (holotype WAM 190.87) — 31, external appearance; 32, gut and gonads.
Microcosmus curvus (QM GH3814) — 33, external appearance; 34, body removed from test; 35, internal organs.
Molgula calvata (SAM E2088) — 36, opening of oviduct. Molgula incidata (QM GH4633) — 37, portion

of branchial sac; 38, internal organs; 39, right side of body, external view. Eugyra millimetra (MV F51475)
40, gonad and kidney on right side. (Scales: 31 — 2cm: 32, 33

5mm; 34, 35 — 2mm; 36, 37 — 0.2mm;
38-40 — 0.5mm).

294

to the yas deferens across the mesial surface of
the ovary, The vas deferens projects slightly into
the atrial cavity and is directed dorsally.

Almost spherical, tailed larvae, with an otolith
but no ocellus, are present in the atrial cavity of
these specimens which were collected in January
The species i Viviparous.

Remarks, The newly recorded specimens are
dorso-ventrally (rather than laterally) fattened.
and the coiled stigmata acound the infundibula
are better developed than those described from
eastern Australia. However, the consistency of the
test, shape of the body, disposition ot muscles,
course of the gut, form of the gonads, and
viviparous habit are the same as in the type
material,

Molgula rima Kowt. 1972
Molgida rima Kott 1972b, p. 250; 1985, p. 385

Distarbe tion

New Rreoro: Victoria (Bass Strait MV F54200). The
siigle specimen ts trom 52m.

Rreauntb Rasap; The species previously was known
only to 0m iq Moreton Bay, Queensland,

Descrir tion

The newly recorded specimen is characteristi-
cally laterally flattened, and sandy, with a thin.
flaccid test that has long. hair-like extensions to
which sand adheres. The left gonad extends
dorsally, from deep in the secondary gut loop.
parallel to the descending Jimb of the primary loop.
The distal end of the gonad, trom which the
gonoducts curve over toward the atrial aperture,
ts located anteriorly. The nght gonad forms a loop
some distance anterior to the anterior end of the
Kidney. The gonads have the usual long, branched,
male follicles around the outside of the long ovary.

Remarks: This species is small, inconspicuous,
and may well occur along the eastern coast,
between the geographically isolated locations from
which it is known at present. The differences
between this species and Mo/gula mulvinensis.
which has similar branched male folheles around
long ovaries, are confirmed in the present
specimen. Although in M. malvinensis the left
gzonad curves around in thé secondary gut loop,
it is oriented in the sare direction as the gut,
its distal end (with the gonoducts) opening toward
the distal end of the gut. In the present species
the left gonad is oriented in the opposite direction,
its distal end directed toward the proximal end
of the descending limb of the gut loop.

MEMOIRS OF THE QUEENSLAND MUSEUM

Genus Eugyra Alder and Hancock, 1870

Eugyra millimetra Kott, 1985
(Fig. 40)
Eurvra nillimepra Katt, 1985, p. 391.
Dist Rist ton

Now Recowwis; Victoria (Western Port, MV F33299
53521 £43402). The new records are from | 5m

Rrourbro Rasac The species was previously known
from only a single specimen lot taken from Stim in Bass
Strait.

Deserivyion

Two specimens (MV F53299) are almost
spherical with a delicate stalk as previously
described. However, the other specimen lot is of
minute (1mm diameter) juvenile specimens fixed
by the whole of their left side to fronds of weed.
The test on the lower (Jett) side of the body Is
thin and transparent. while that on the upper
(right) side is covered with sand, These small
individuals sometimes lie close together, often
attached lo the sand on one another's test.

‘The muscle band across the dorsal surface
reported by Kott (1985) is sometimes, but not
always, present, [tis formed when separate bands
in that region contract and appear to coalesce to
form a single, wide band. The green stomach has
fine, parallel, glandular ridges in its wall as weil
as deeper grooves that divide it into 4 sections
(see Kort 1985).

Remarks: Kott (1985) used the presence of a
single. wide, muscle band across the dorsal surface,
and the posterior Nexure of the right ovary to
distinguish this species from others in the genus,
The former occurs only when the separate bands
in this region contract together to form u single,
wide band, However, in immature specimens
without developed ovaries the division of the
stomach wall into 4 broad sections provides a
reliable character to distinguish this species from
others.

Genus Pareugyrioides Hartmeyer, 1914

Pareugyrioides exigua (Kott. 1972)

Molgula exigua Kott 1972b, p. 249; 1985, p. 394 and
synonymy,
Dis rrRigurion

Nrw Rereorns; Victoria (Western Port, MV5d208:
Bass Strait, MV F54320 54199). Specimens were taken
at 55m.

Recorpno RaAxgr- The species has previously been
recorded fram Bass Strait. Moreton Bay (Queensland)
and Indonesia, Individuals are small (usually less than
lem diameter) and sandy. and very likely will be found
to oecur at intermediate locations.

DESCRIPTION
‘The newly recorded specimens are small, about

THE AUSTRALIAN ASCIDIACEA |. SUPPLEMENT

0.3em in diameter. and tailed larvae, with otolith
but no ocellus, are the peribranchial cavily-

Remarks, Individuals were reported (Kort
1972b) previously to reach sexual maturity at
0.Sem, erroneously recorded as 0.5mm by Kott
(1985). The newly recorded specimens indicale that
it occurs even earlier in their life histary.

ECOLOGICAL NOTES

Included in the newly recorded material are
specimens from a survey of sea grass beds at
Albany (Western Australia) made by Drs P,
Hutchings of the Australian Museum and 1,
Walker of the University of Western Australia in
1987; and a survey of Cnb Point (Western Port-
Victoria) by the Victorian Department of Fisheries
and Wildlife in 1965,

The ascidian fauna of the sea grass (Posidonia
australis and P. sinuesa) beds at Albany ts
dominated hy small individuals of Pelvearpa flave
and Micrecosmus squamiger usually with epibie
otic ascidians. Epibionts are Stolonica reducta,
Palyzoa exigua a.sp.. occasional small colonies
af Borrv/lus stewarrensis and Rinerella peduncu-
lata, und (rarely) small specimens of Molgwle
calvata, M. ficuxs and M. incidata. Ascidiella
aspersa, Asvidia gemmata, and Prura stolonifera,
all recorded previously from Albany, occur also
in the sea grass beds together with occasional
specimens of Polyearpa chinensis and P. lucilla,
both of Which may be occupying a refuge at the
limits of their tespective geographic ranges,
Pulyearpa chinensis. a tropical species formerly
known from the eastern coast of Australia south
to Bass Strait and on the western coast to
Cockburn Sound, is relatively Common in shallow
embayments (such as Moreton Bay and Gladstone
Harbour) where sea grasses oecur. Similarly,
Palycarpa lucitla, also more frequently encoun-
tered in tropical waters (see above), has been
recorded from Upper Spencer Gulf where. again,
sea grasses abound.

The species from Crib Point, Victoria represent
a remarkably diverse, sand-adapted community
of small. benthic species, many unattached,
flattened. and sand-covered. and dominated by
taxa with spiral stigmata (in the families Agne-
siidae and Molgulidae). The majority of species
are known to be temperate. many previously
recorded from Bass Strait, although some are
tropical forms, possibly occupying a refuge al the
limits of their respective ranges. The species taken
from Crib Point are: Agnesiv glaciata, Polvearpa
directa nsp., P plenovata, Po pracera, Pyura
molsuloides, P. arenosa, Microcosmus squamiger.

295

Mofeula calvata, M. mollis, M. malvinensis, M.
mortenyeni, M. rima, Kusryra millimetre,

The sand-mud benthic fauna of Moreton Bay
has similar characteristics to those of the Crib
Point community, Some of the same species (072,
Agnesia glaciata, Molgula rima and Kugyra
millinretra, see Kott 1972b 1985), as well as related
ones, occur in both locations, and Moreton Bay
may be a refuge for species at the end of their
northern ranges as well as an ecological refuge
for sand-adapted communities,

The callections from Torres Strait were dredged
from a sandy bottom, possibly in regions af fast
current flow. For, although free-living benthic
species that be on the surface of the sea floor,
such as Moleula diversa and Polycarpa lucilla are
recorded, they are rare in. these collections. Aseidla
seaevola and Polvearpa decipiens, the tough P.
chinensis and FP. aurua, and the robust Prura
ohexa and P. yacciforniiy, ave all found partially
buried in the substrate. By far the most common
species in these locations, however. are relatively
small specimens of Mireracosnius exasperqrus, M-
helleri, M. squamiger and MM. steleniferus, which
have tough tests with strong adhesive qualities.
These often form large aggregates.

The records from Torres Strait confirm a
continuous. geographic range from the north»
eastern Australian coast to Indonesian waters for
Ascidia scaevola, Phallusia julinea, Amphicarpa
duploplicata, Styela canopus. Polycarpa aurita,
P decipiens, P. papillata, and Pyura ohesa.
Polvearpa chinensis, Pyura sacciformis and
Molgula diversa (Lormerly known from the
western Pacific and north-eastern Australia).
Microvosmus squamiger (Known from north-
western and north-eastern Australia and the Red
Sea), and pantropical Herdmania momus, Micro-

coymus exasperaius and M. helleri were also taken

from ‘Torres Strait. Microcosmus stoloniferus is
the only species newly recorded from Torres Strait
to have formerly been regarded as indigenous,

ACKNOWLEDGEMENTS

Scoreshy Shepherd, Nigel Holmes and their
colleagues of South Australian Fisheries Depart-
ment collected South Australian material referred
to above. Dr b. Rowe of the Australian Museum,
Ms L. Marsh of the Western Australian Museum
and Ms S. Boyd of the Museum of Victoria
arranged the loan of unidentified material that
included some of the new species described herein.
David Parry and Stephen Cook assisted in the
field at Heron |. and in Moreton Bay, Stephen

296

Cook also completed the line drawings [rom the
author's sketches,

Collecting at Heron |. was made possible
through Marine Science and Technology Grant
83/1320 to the author and C. Hawkins.

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298

INDEX TO TAXA

(Taxon descriptions and figures in bold)

Agnesia glaciata, 295
Amphicarpa, 277 279
duploplicata, 295

elongata, 280
nodula, 277
Ascidia,
aenigmatica, 267
gemmata, 295
granosa, 267
papillosa, 288
scaevola, 295
Ascidiella aspersa, 295

Botryllinae, 286
Botryllocarpa, 283 284
elongata, 283-86
pizoni, 286
viridis, 284 286
Botryllus,
stewartensis, 285 286 295
tuberatus, 286

Chorizocarpa, 284
Cnemidocarpa, 268
barbata, 268-70

bythia, 270
digonas, 270
lobata, 270
tripartita, 270
Crenicella, 288
antipoda, 288 290

Ecteinascidia, 268

turbinata, 268
Eugyra millimetra, 293 294 295
Eusynstyela, 276

grandis, 273 276

monotestis, 276

larona, 276 277

Halocynthia, 288
papillosa, 288

Hartmeyeria formosa, 292

Herdmania momus, 295

Metandrocarpa, 283
agitata, 283
indica, 283
miniseula, 283 285

Micrecosmus, 289
curvus, 289 293
exasperatus, 289
helleri, 295
madagascariensis. 289 291
planus, 291
squamiger, 295
staloniferus, 291-2 295

Microgastra, 267
granosa, 267

Molgula,
calvata, 292 293 295
diversa, 295
exigua, 294
fieus, 295
incidata, 295 292 293
malvinensis, 294 295
mollis, 295
mortenseni, 295
rima, 294 295

Pareugyrioides, 294
exigua, 294-5
Perophora, 267 268
aaopa, 268
listeri, 268
multistigmata, 268
sabulosa, 267-8 269
Perophoridae, 267
Phallusia julinea, 295
Phlebobranchia, 267
Plurellidae, 267
Polyandracarpa, 276
maxima, 277
sabanillae, 275
sparsa, 276
tarona, 276
Polyandrocarpa (Monandrocarpa), 276
Polyearpa, 270
albatrossi, 274
aurita, 270 295
biscayensis, 274
chinensis, 295
decipiens, 295
directa, 271 273 295
flava, 271-2 295
indiana, 274
itera, 274
kapala, 272-4
lucilla, 272 295
nota, 27| 273 274-5

MEMOIRS OF THE QUEENSLAND MUSEUM

obscura, 271
papillata, 295
papyra, 271
plenovata, 271 275 295
porculus, 274
procera, 295
seudoalbatrossi, 274
sobria, 271
tumida, 275
Polyzoa, 280 295
exigua, 280-2
nodosa, 281 282-3
translucida, 282
violacea, 282
Polyzoinae, 276
Protobotryllus, 284
Pyura, 287
arenosa, 287 295
molguloides, 295
obesa, 295
rapaformis, 287-8 293
sacciformis, 295
spinifera, 288
spinosa, 288
stolonifera, 288 290 295
tasmanensis, 288
Pyuridae, 287

Ritterella pedunculata, 295

Seriocarpa, 277
Stolidobranchia, 268
Stolonica, 277-8 279
agnata, 277 278
aluta, 277 278 280
australis, 277 278-9 281
carnosa, 277
diptycha, 277
duploplicata, 277
nodula, 277 278% 279-80
reducta, 277 278 280 281
socialis, 277
truncata, 277 278 280
vesicularis, 273 274
Styela,
aurita, 270
canopus, 295
Styelidae, 268
Styelinae, 268
Symplegma, 284
arenosa, 282

CONTENTS
Kor, P.
The Australian Ascidiacea part 2, Aplousobranchia (1) ...........ccccccccccccccccceees 1-266

Kor, P.
The Australian Ascidiacea, Phlebobranchia and Stolidobranchia, Supplement........... 267-298