Parasite fauna of Australian marine oligochaetes

22 Pages·2001·6.6 MB·English

by  Sascha L Hallett

PARASITE FAUNA OF AUSTRALIAN MARINE OL1GOCHAETES
SASCHA L. HALLETT, CHRISTER ERSEUS, PETERJ. CTDONOGHUH
AND ROBERT G I.FSTER
J.
llallett, S.L., Erseus, C\, CTDonoghuc, P.J. & Lester, R.J.G. 2001 06 30: Parasite fauna of
Australian marine oligochaetes. Memoirs ofthe Queensland Museum 46(2): 555-576.
Brisbane. ISSN 0079-8835.
A survey of7,200 marine oligochaetes from Queensland (Moreton Bay, Brisbane, Heron
Island and Lizard Island), New South Wales (Georges River, Sydney) and the Northern
Territory (Darwin Harbour) revealed infections by 5 major parasite groups. Tubificid
oligochaetes ofthe Limnodriloidinae, Phallodrilinae and Rhyacodrilinae were host to: 10
actinosporeans (Myxozoa) namely Sphaeractinomyxon erset, S. leptocapsula, Endocapsa
rosulata, E. stepheni, Endocapsa type 1 nov., Tetraspora cliscoidca, T. rotundum,
TriactinomyxonofRoubaletal., 1997,Triactinomyxontype 1 nov.andTriactinomyxontype
2 nov.; an aseptate eugregarine (Apicomplexa) Oligochaetocystis sp.; an astomale ciliale
(Ciliophora); a peritrichous ciliate Scyphidia sp. (Ciliophora); mermithid nematodes
(Nematoda); a haplosporidian (Haplosporidia); and a eoccidian (Apicomplexa). A single
D
enchytraeidspecimen,Graniasp.,harbouredastomateciliates. Australia, actinosporeans,
marine oligochaetes, parasites,protozoans.
SaschaL. Hallett (sascha(a xvildfire.com.au), PeterJ. O'Donoghuc & RobertJ.G. Lester,
Department ofMicrobiology and Parasitology, The University ofQueensland, St Lucia,
Queensland4072,Australia;ChristerErseus,DepartmentofInvertebrateZoology. Swedish
MuseumofNaturalHistory, Box50007,SE-J0405Stockholm, Sweden;22September2000.
The literature suggeststhat parasites ofmarine species for which no other form of life cycle is
oligochaetes are common (Gicre & Pfannkuche, known. No complete life cycle has been
1982; Raflos & Cooper, 1990), yet few specific determined for any marine myxozoan.
examples can be found. Documented parasites Myxosporeans are common in marine fish in
belong principally to the protozoan orders Australia;thisstudywasundertakentodetermine
Asiomata (Ciliophora: Holotricha) and if actinosporeans were present in Australian
Gregarinida(Apicomplexa: Telosporidia)withat marine oligochaetes. Some ofour early findings
least 13 and 5 species described, respectively have been published elsewhere. These records
(Giere & Pfannkuche, 1982). Six actinosporeans are of the actinosporeans Sphaeraclinomyxon
(Myxozoa), Sphaeractinomyxon stolci Caullery ersei Hallett, (TDonoghue & Lester, 1998, S.
& Mesnil, 1904, Sphaeraclinomyxon type & 2 leptocapsula Hallett, Erseus & Lester, 1999,
1 &
llallett ct ah, 1997a and Aurantiactinomyxon Endocapsa rosulata Hallett, Erseus Lester.
type 1, 2 & 3 llallettetal., 1997a, alsohave'been 1999, E. stepheni Hallett, Erseus& Lester, 1999,
&
recorded. Prior to this study, no parasites had Tetraspora discoidea Hallett Lester, 1999, T.
been recorded from an Australian marine roiundum Hallett & Lester, 1999, and
oligochaete. Triactinomyxon ofRoubal et al., 1997. Here, we
present a review of all parasite types so far
Freshwater oligochaetes are reported as hosts encountered in Australian marine oligochaetes,
to these parasite groups as well as to cestodes including published records.
(e.g. Archigetes iowensis and Hunterella
nodulosa), nematodes (e.g. Eustrongytides sp., MATERIALS AND METHODS
&
Dioetophyma renale) (Raftos Cooper, 1990)
Sediment samples were collected to a depth of
and rotifers Albertia spp. (Koste, 1970; Erseus,
1976). They also are host to about 116 15cm from the intertidal zone in Moreton Hay
(27°15-25*S), and from Heron (23°27'S.
actinosporeans (McGeorge et al., 1997; Lorn et
al., 1997; Xiao & Desser, 1998a, b; El-Mansy et 151 55'E) and Lizard (14°4(TS, 145°28'E)
salt.,ag1e9s98bi,nc)t;hseomliefeofctyhcelseesparoafsimteysxaorsepaoltreeranantse oIlsilgaoncdhsaedtuersinwger1e99al5s-o19o9b7tai(nFeidg.fr1o).m ISnyfdencetye,d
(Myxozoa) in fish(see Kentctal., 1994a; Lornet NSW (33°53'S, 151°I0?E) and Darwin, NT
ah, 1997). Todate, some 24 lifecycleshavebeen (12°25'S, 130°518E) (Fig. IB). Sediment was
elucidated and they have all involved freshwater collected in 500ml jars, each emptied into a
556 MEMOIRS OF THE QUEENSLAND MUSEUM
seawater was added to inhibit movement.
HaysInter / North Parasites (with the exception ofthose obtained
fromLizardIsland,DarwinHarbourandSydney)
RedcltffePoint
werephotographed,sketchedandmeasuredprior
to fixation in eitherBouirfs fixative for24hours
for host identification or 3% gluteraldehyde in
0.066M cacodylate buffer for 24 hours for
electron microscopy. For host identification,
infected oligochaetes were transferred to 70%
ethanol, stained in alcoholic paracarmine,
mountedwhole inCanada Balsam and examined
underacompoundmicroscope.Nematodes were
fixed within the oligochaete host and several
were cleared and stained with chlorlactophenol
and Mayer's haemotoxylin. Actinosporean
descriptions follow the guidelines presented by
Lorn et al. (1997) except that 'germ cell' is used
for 'daughter cells1 and we give an additional
measurement 'basal width" which is maximum
width ofthe spore in apical view. New forms are
identified in accordance with Kent et al. (1994)
and Lorn et al. (1997). Reference oligochaete
hostspecimenscontainingparasitesarelodgedin
the Queensland Museum (QM), Brisbane.
RESULTS
NOflh A total of 5,200 oligochaetes were examined
from Moreton Bay and a further 2,000
oligochaetes from Heron Island. The density ol
Heron worms sampled in Brisbanewas upto0.8 worms
Island per cm3 Six parasitic/commensal groups were
.
identified: actinosporeans (Myxozoa), aseptate
Brisbane
eugregarines (Apicomplexa), astomate and
peritrichous ciliates (Ciliophora), mermithid
Sydney nematodes (Nematoda), haplosporidians
(Haplosporidia) and coccidians (Apicomplexa)
(Tables 1,2).
500km B Phylum MYXOZOA Grasse, 1970
Class MYXOSPOREAButschli, 1881
FIG 1.A,Moreton Baycollectinglocalities. B,Mapof ACTINOSPOREAN FORMS Kent et al., 1994
Australia showing other collecting localities.
Brisbane incorporates Moreton Bay. Infections by actinosporeans were detected in
196 (3.8%) of5,200 worms from Moreton Bay,
bthuocrkoeutghcloyntmaiinxiendg aanbdoutthe4 sluipterersnaotfantseapwoautreerd, w25or(m1.s3%f)roomf2L,i0z0a0rdwoIsr.mOsnefrwoomrHmerfornomIs.Maonrdetinon8
Bay harboured a double infection of Sphaer-
through a0.4mm sieve. The contentsofthe sieve actinomyxon ersei and Tetraspora discoidea.
werewashed intoapetri dish andthe supernatant Three worms, Duridrilus sp.(QMG463613),
returnedtothebucket. Thisprocess was repeated Limnodriloides sp. (QMG463615) and
about5timespersample.Thematerialinthepetri Doliodrilus diverticulatus (QMG463614) from
dish was then examined under a dissection Darwin Harbourand an unidentifiedoligochaete
microscope and any oligochaetes present were from Georges River, Sydney, harboured un-
recovered for detailed examination under a identifiedactinosporeans(all fixedsamples).Ten
compound microscope. The worms were placed actinosporeans belonging to 4 collective groups
on glass slides and a drop of 25% ethanol in were found in marine oligochaetes (Table 1).
PARASITES OF MARINE OLIGOCHAETES 557
TABLE 1. Actinosporeans from Australian marine oligochaetes.
Actinosporean No.InfectedHosts Host Site
Sphaeractinomyxonersei 2 Doliodrilusdiverticulatus MoretonBay
Limnodriloidescf.victortensis MoretonBay
4I4 Tubificidaesp./spp. MoretonBay
2 TTuhbailfaiscsioddareilsipd.e/sspcpf"..gurwitschi HeronIsland
1 Limnodriloideslateroparus LizardIsland
2 Bathydrilussp. Lizard Island
T LizardIsland
Sphaeractinomyxonspp. 24 Tubificidaesp./spp. MoretonBay
S. leptocapsula 2 Herontdrilussp. LizardIsland
Endocapsarosulata 3 Ilclcrodriluscf.kcenani HeronIsland
1 Thalassodrilidescfgurwitschi LizardIsland
1 llcronidrilussp. LizardIsland
9 1ubificidaesp./spp. MoretonBay
E. cf rosulata 6 Tubificidaesp./spp. !leronIsland
E.Stephen! 1 ilclcrodriluscf.keenani HeronIsland
2 Heterodrilusqueenslandicus 1leronIsland
1 Tubificidaesp. Heron Island
Endocapsatype 1 8 Tubificidaespp MoretonBay
2 Doliodrilusdiverticulatus MoretonBay
Tetrasporadiscoidea 12 Tubificidaesp./spp. MoretonBay
Tetrasporarotundum 3 1ubificidae--.p. spp. MoretonBa\
Triadinnmyxonsp. 214 T1uibminfoidciid\aleoisdpe.$/s>.p1p.iicton&isis MMoorreettoonnBBaayy
Triactinomyxontype 1 1 Limnodriloidinaesp. MoretonBay
Triactinomyxontype2 1 Tubificidaesp. Moreton Ba\
UScnopiehdlaeoenmrtiaiccfitieindnf:oemctyixoind 5130 TTTuuubbbiiifffiiiccciiidddaaaeeesssppp..i//ssspppppp... MM1oolerrreeottnooInnslBBaaanyyd
cinoteelstoimniacl iinnffeeccttiioonn 112 LDuirmindordirtiulsoisdpe.ssp. DDaarrwwiinnHHaarrbboouurr
ccinoofeeellcootmmiiioncciinnffeeccttiioonn 11 TDuobliifoidrciilduasedspi.verticulatus DarwSiyndnHearybour
1
SPHAERACTINOMYXON FORMS (width) 3-5.5u.rn, length 3-7urn. Sporoplasm,
rounded triangular in apical view, single
Sphaeractinomyxon ersei Hallett, binucleate, about 46 germ cells, almost fills the
O'Donoghue & Lester, 1998 spore cavity.
(Fig. 2A)
REMARKS.S. erseiwasdetectedin47(0.9%)of
TYPE HOST. Doliodrilus diverticulatus Erseus, 1985 5,200oligochaetesexaminedfromMoretonBay;
(Tubificidae: Limnodriloidinae). the number may be higher because 77 un-
identified (immature) coelomic actinosporeans
cSoIeTlEomIaNndHmOaStTu.resIpmomraetsuprreesesnttaginestheloicntaetsetdinawlilthuimnen.the Lwiemrneoadlrsioloriecdoersdecdf.(sveiectToarbileens1i)s. IBtrailnskohiunrfsetcte&d
TYPELOCALITY.BoggyCreek,MoretonBay, 27°24'S, Baker, 1979 from BoggyCreek,tubificid species
153°09*E. from Heron Is. and Thalassodrilides cf.
gurwitschi (Hrabe, 1971) (Limnodriloidinae),
SPECIMENSLODGED.QMG462452(#110),G462453 Limnodriloides lateroparus Erseus, 1997 and
(#185), G462465 (#210), G463601 (LI95-4), G463602 Bathydrilus sp. (immature) (Tubificidae:
(LI95-24/1),G463603 (LI95-24a), G463604(LI95-24b). Phallodrilinae) from Lizard Is.
DESCRIPTION. Triradially symmetrical spores Sphaeractinomyxon leptocapsula
packed in groups of eight in the pansporocyst. Hallett, Erseus & Lester, 1999
Spores triangular in apical view, diameter (Fig. 2B)
17-34um, basal width L7-33um; ellipsoidal in
side view, length 17-33urn. Polar capsules, 3, TYPE HOST Heronidrilus sp, (2 immature specimens
round to pyriform, centrally located, diameter infected)(Tubificidae: Rhyacodrilinae).
558 MEMOIRS OF THE QUEENSLAND MUSEUM
TABU; 2. Parasites and commensals identified from Australianmarine oligochaetes. #NR = not recorded.
Parasite No.InfectedHosts Host Site
AP1COMPLEXA
OUtniigdpencthiafeiteodcyesoteicsidsoi.anspecies NiR TLuibminfoidcriidlaoeidspi.naesp./spp. MMoorreeltoonnBBaayy
C1LIOPHORA
Radiophyasp. 43+ Tubificidaespp. HeronIsland
SUcnyipdeHnitdiifaiespd,astome N1R CLirmannoidarislp.oidinaesp./spp. M1olerreotnoInslBaanyd
HAPLOSPORTDIA
Haphsporidiumsp. 115 HTuebtiefriocdirdialeussps.p/.spp. 11lleerroonnIIssllaanndd
NEMATODA
Mermithidnematode 1 Heterodriluscf.keenani HeronIsland
4 Tubiiicidaesp./spp. HeronIsland
SITEINHOST. Coelom. SPECIMENS LODGED. QM G462454 (H122),
G462455 (H146), G463605 (LI95-24c), G463606
TYPE LOCALITY. Intertidal sand, Lizard Is., I4°40'S, (LI95-16a),G462723 (#200).
145°28'E.
DESCRIPTION. Sporediameter25-27um,basal
SPECIMENS LODGED. QMG462459 (LI95-16b), width 25-28um, length 20-23ujn, resembles
G462460(LI95-16e). rosetteinapicalview,compresseddorsoventrally
DESCRIPTION. Spores triangular in apical in side view (Fig. 2C); develops in groups of 8
view, diameter 20-24um, basal width 20-23um, within pansporocysts (55-75u-m). Valve cells
length 17-22um. Outer valve cell membrane inner membrane subspherical; outer membrane
follows contours ofinner valve cell membrane. followscontoursofdorsalandventralsurfacesof
Polar capsules ~5|im long, slender, pyriform, this but exhibits swellings laterally in 3 regions
orientated with pointed ends facing centre of equidistantly apart; inner and outer membranes
spore, each positionedoppositeacornerofspore close at each valvejunction; suture lines prom-
about midway along spore radius, each contain inent. Valve cell swellings formed within host,
polar filament with at least two turns. In side little or no further expansion on contact with
view, spore ellipsoidal to broadpyriform. Suture seawater (Fig. 2D). Cavity diameter 19-23jim,
lines not discernible. Pansporocysts each with ellipsoidal in side view. Polar capsules
eight spores. ellipsoidal, 4-5u,m long and wide, located
beneath a suture line anteriorly in, but not
REMARKS. S. leptocapsula was observed on extruding from, spore, adjacent to remains of
only in 2 oligochaetes from Lizard Is. capsulogeniccellandperpendiculartoprocesses,
ENDOCAPSAFORMS embeddedinsporoplasminsideview, withpolar
filament with at least 3 turns. Sporoplasm
Endocapsa rosulata granular, remaining areas ofspore clear.
Hallett, Erscus & Lester, 1999
(Fig. 2C-F) REMARKS. Thalassodrilidescf.gurwitschiand
Heronidrilus sp. (immature) from Lizard Is. and
TYPE HOST Heterodrilus cf. keenani Erseus, 1981 tubificids from Moreton Bay also harboured this
(Tubificidae: Rhyacodrilinae). parasite. Nine tubificids of the 5,200
SinITinEteIstNinHalOSluTmeInmm(aFitgu.r2eEs-tFa)g.esincoelom;maturespores owleirgeocihnafeetcteesd.frSopmorBesogwgeyreCroebeske,rvMeodroentloyninBatyh,e
coelom; none were found in the gut lumen as
TYPE LOCALITY. Heron Is., 23°27'S, 151°55'E. were Heron Is. infections. Spores were smaller
FIG.2.Aclinosporeansfrom marineoligochaetes. A, matureSphaeractinomyxonerseispores(eachwith3 polar
capsules)intheintestinal lumenofalimnodriloidineoligochaetefromMoretonBay.Fresh, unstainedmaterial.
Scale = 25u.m; B. Sphaeractinomyxon leptocapsula pansporocysts with eight spores in the coelom of an
oligochaete. Preserved material from Lizard Island. Scale = 50jjm. C-F, Endocapsarosulata, fresh unstained
material. C, Moreton Bay; D-F, Heron Island. C, spore in sea water. Scale= 20um; D, spores emerging from
host.Scale=25um;E,developingstagesof£. cf.rosulataincoelom.Scale= 150um;F,sporesofE. cf.rosulata
free in intestinal lumen. Scale = 150um.
PARASITES 01 MARINE OLJGOCHA] Tl '•
Ki. ' / m;-Al ltfK?
m
SB
' |Kj
I
S'*>i
560 MEMOIRS OF THE QUEENSLAND MUSEUM
than those from Heron Is. being 20-25um in other, each situated beneath a suture (and
diameter and 25-28u.m in basal width. therefore opposite a spore corner) (Fig. 3A),
embedded in anterior part ofsporoplasm, do not
Endocapsa&stepheni Hallett, Erseus form anapex(Fig.3B). Sporeroundinsideview,
Lester, 1999 length 16-28u.m(22pm,n=7),diameter 19-3lum
TYPE HOST. Ileterodriluscfkeenani. (25pm, n=6) (Fig. 3B).
SITE IN HOST Coelom. REMARKS. Some spores had smooth rather
than pinched comers. The non-protrusive polar
TYPE LOCALITY. Heron Is., 23D27'S, 15]°55'E. capsules and reduced swellings, at times present
SPECIMENS LODGED. QM G462456 (H132), wEintdhoicnaptshea.hoTswt,opoltahceer tfhoirsmsacotfiEnonsdpoocraepansainhatvhee
G462457 (H135), G462458 (HI48). been recorded: E. rosulata; and E. stepheni.
DESCRIPTION. Spore, diameter 25-28um, Endocapsa type 1 differs from both these in the
basal width 23-25um, length -20jxm, irregularly shape of the spore and swellings. Its valve
shaped in apical view. Spore cavity diameter swellings encompass fully the spore body
~23jim. Valve cells follow shape of roughly (visible in both apical and side view), whereas
triangularsporecavitybutwith asingle lobe-like those of E. rosulata do not, and it possesses 3
swelling at one corner. Sutures, detectable, from swellings whereas E. stepheni forms just one.
corners to middle ofspore. Sporoplasm roughly The Aurantiactinomyxon types described from
triangularinapical view,almost fillssporecavity, Hong Kong marine oligochaetes possess valve
depressed in side view where polar capsules projections rather than swellings and the spores
positioned. Polar capsules round in apical view; are considerably smaller, being less than 20pm
diameter 4-5^m, pyriform in side view, length (Hallett et al., 1997). The principal difference
4-5um, centrally located in spore, close to each betweentheNeoactinomyxontypesdescribedby
other, beneath suture lines. Spore appearing El-Mansyetal. (1998b)and Endocapsatype 1 is
ellipsoidal in side view, except that valve cells that the valve cells ofthe former form triangular
form an extension at one side. shaped extensionswhereas theyarecurvedin the
valve cells of the latter. Endocapsa type 1 was
REMARKS. One Heierodrtlus cf. keenani, 2 H. recorded from 8 tubificid specimens.
queenslandicus Jamieson, 997 and
1 1 TETRASPORAFORMS
unidentified tubillcid were infected with this
actinosporean. Tetraspora discoidea Hallett & Lester, 1999
Endocapsa type 1 nov. (Fig. 4A)
(Fig. 3) TYPE HOST Doliodrilw diverticulatus Erseus, 1985
(Tubiflcidae: Limnodriloidinae).
HOST. Immaturetubificids.
SITE IN HOST. Coelom.
SITE IN HOST Developingstages inperitoneum, mature
spores in coelom and intestinal lumen. TYPELOCALITY.Bou^Creek,MoretonBay,27°24,S.
153°09,E.
LOCALITIES. Havs Inlet and Boggy Creek, Moreton
Bay^^S, 153°04,Eand27°24'S, 153°09'E. SPECIMENSLODGED.QMG462461 (#104).G462462
(#114),G462463(#96).
DESCRIPTION. Spores subtriangular in apical
view, diameter 17-30um (22|am, n=8), basal DESCRIPTION. Sporediameter33-52um,basal
width 19-3lpm (25pm, n=2) (Eig. 3A). Spore width 33-38pm, length 14-22pm, disc-like,
body (inner valve cell membrane) basically almost round, valve junctions form comer in
round butcorner formed at 3-way valvejunction apical view, dorsoventrally compressed in side-
(Fig. 3A, C). Valve cells, upon contact with sea view. Valvecellprocessesabsent. Polarcapsules.
water, form 3 equally-sized biconcave processes 3, subspherical in apical viewr, each within a
(swellings) whichjoin at their narrowest part at pyriform capsulogenic cell, situated beneath a
each 3-way valve junction (Fig. 3A, C). spore suture line, opposite a spore corner, bases
Swellings frequently present prior to spore proximal; pyriform in side view, located midway
contactwithseawater. Polarcapsulesround,oval across spore at dorsal surface of sporoplasm.
to pyriform in side view, diameter 3-5um (4u.m, Polar filament oblique, at least 7 turns.
n=4), located centrally in spore, proximal to one Sporoplasm, shape similar to spore, unisporal.
PARASITES OF MARINE OLIGOCHAETES 561
w
™.-'*
FIG.3.Endocapsatype 1 nov.fromfreshmaterialfromMoretonBay.A,drawingofapicalviewandB,sideview.
Scale= 5um. C, spores in seawater. Scale = 50pm.
contains at least one somatic nucleus and >100 TYPELOCALITY.BoggyCreek,MoretonBay, 27°24,S,
germ cells. Pansporocysts, freely floatingwithin 153°09,E.
host coelom, irregularly shaped, 47-70(101, each
containing 4 developing spores. Spores do not SPECIMENS LODGED. QM G462464(#113,#186).
alterinsizeorshapefollowingreleasefromhost.
Development between pansporocysts DESCRIPTION. Triradially symmetrical spores
asynchronous, but within synchronous. packed in groups of eight in the pansporocyst.
Spores triangular in apical view, diameter
REMARKS. Twelve immature unidentifiable
17-34(im, basal width 17-33um; ellipsoidal in
Tubificidae from Boggy Creek and 2 specimens
sideview, length 17-33fim. Polarcapsules,three,
of D. diverticulatus from Hays Inlet were
round to pyriform, centrally located, diameter
infected with this parasite.
(width) 3-5.5(.tm, length 3-7um. Sporoplasm,
Tetraspora rotundum Hallett & Lester, 1999 rounded triangular in apical view, single
(Fig.4B) binucleate, about 46 germ cells, almost fills the
spore cavity.
TYPEHOST ImmatureTubificidaesp.
REMARKS. Three tubificids from Boggy Creek
SITE IN HOST. Coelom. harboured T. rotundum.
562 MEMOIRS OF THE QUEENSLAND MUSEUM
pyriform, protrude at apex, bases abut, anterior
end of each at slight angle (c.45°) facing away
from other polar capsules (Fig.5 inset). Stylus
widens gradually from tip to base (to ~22ji.ni).
Sporoplasm, single, 17um long, with indis-
cernible number ofgerm cells, irregularly in the
stylus.
REMARKS. This Triactinomyxon most closely
resembles T. legeri Mackinnon & Adam, 1924
and T. ignotum Stole, 1899, butsporedimensions
are most like T. legeri (style 90-140(j.m, arms
150u.m, sporoplasm 15-20jim [Marques, 19841).
T. legeriand T. ignotumdifferin sizeandnumber
ofgerm cells inthe sporoplasm {T. legeri= 24; T.
ignotum = 8) and both develop in the intestinal
epithelium of Tubifex freshwater oligochaetes.
Triactinomyxon differs from T. legeri in its host
and environment but these characters are con-
sidered insufficient to establish a new species.
The numberofgenu cells was indeterminableby
light microscopy in the marine triactinomyxon
butthe size ofthe sporoplasm suggests about 32.
The orientation ofthe processes varied between
spores emitted from a single host and were
directed out, up or down; spores were always
observed under a coverslip and this may have
FIG.4. Tetrasporaspores; freshunstainedmaterial.A, influencedtheorientation ofthe projections. The
T- discoidea in seawater. Scale = lOum. B, T. range in spore length and arm length appears
rScoailuend=u2m0puamn.sporocysts (arrows) with four spores. initially largebutthesearecomparablewithother
species (range of 50 and lOOurn respectively)
(Marques, 1984; Lorn & Dykova, 1992b).
TRIACTINOMYXONFORMS This was the first Triactinomyxon recorded
from the marine environment. At least 25
Triactinomyxon ofRoubal et al., 1997 oligochaetes harboured the parasite. Other hosts
(Figs 5, 6) than Limnodriloides cf. victoriensis were
IThalassodrilides sp. (Limnodrilinae) and
HOST. Limnodriloidescf. vicroriensis. Duridrdus sp. (Phallodrilinae). Infections were
difficult to detect without squashing and killing
SITE IN HOST. Immature stages in intestinal epithelium the hosts. Clusters of 3 polar capsules in the
(Fig. 6B, D) and mature spores present also in intestinal intestinal epithelium or a distended intestine are
lumen. indicative ofan infection (Fig. 6B, D). Another
LOCALITIES. Hays Inlet, Clontaif Point, and Boggy 12oligochaeteshaddevelopingTriactinomyxon-
Creek, Moreton Bay, 27°15-25'S likestagesinthe intestinebutno freesporeswere
seen (QM G463607 #203).
DESCRIPTION (expanded from Roubal et al.
1997). Spore anchor-shaped, total lengths Triactinomyxon type 1 nov.
96-142u.ni (125um, n=6) (Fig. 5A). Valve cells (Figs 5, 6)
inflate upon contact with seawater to form 3 HOST. Immature limnodriloidineoligochaete.
anteriorly curved projections (caudal processes)
from spore stylus at 90-100°angle (a) (Figs. 5A, SITE IN HOST. Posterior gut distended with
6A). Projections equal length 94-185u,rn pansporocysts.
(138(im, n=6) and width, at end taper to a point, LOCALITY. Boggy Creek,27°24'S, 153°09'E.
equidistantly apart, arm base not wider than
stylus base. Polar capsules, three. 3-5u,m (4u.m, DESCRIPTION. Ovoid spores in pansporocyst
n=5) long, located at anterior end of stylus, become anchor-shaped when exposed to
PARASITES OF MARINE OLIGOCHAETES 563
type most closely resembles Triactinomyxon
1
type 4 of El-Mansy et al., 1998c and
Triactinomyxon WE' of Xiao & Desser, 1998a.
However, although the length of the processes
and polar capsules are similar in type 4 of
El-Mansyetal. andourtype 1,theaveragelength
ofthesporebody(45um)isgreaterandthelength
ofthe style (149um) less forthe formerthanthat
of the latter. Similarly, the process length of
Triactinomyxon 'E1 is within the range of
Triactinomyxon type but the polar capsules of
1,
the formerare smaller(5u,m) as is the total spore
length (spore axis 190-210um).
Triactinomyxon type 2 nov.
(Fig. 7)
HOST. Unidentifiedtubificidoligochaete.
SITE IN HOST. Not possible to determine ifinfection is
coelomic or intestinal; intestine distended with
pansporocyst within its boundary, but the latter may be
aboveratherthanwithin intestine.
TYPELOCALITY. Boggy Creek, 27°24'S, 153°09'E.
DESCRIPTION. Pansporocyst -139um across,
with 8 subspherical spores (Fig. 7A). Spores fill
out into characteristic triactinomyxon anchor-
FIG. 5. Drawing ofTriactinomyxon types. Side view shapeaftercontactwithseawater(Fig. 7C). Polar
of spores fully expanded in seawater. A, capsules 3, pyriform, -8 x 6urn, at anterior end
Triactinomyxon of Roubal et al., 1997. Scale = ofstylus (Fig. 7B). Spore -346pm long, ~38jim
50jim. [Inset: Spore in intestinal lumen befor=e wide,narrowedanteriorly,posteriorenddividing
contact with seawater and valve expansion. Scale
lOum.] B, Triactinomyxon type nov. Scale = into 3 caudal processes directed posteriorly
lOOum. 1 which taper at ends, ^517um long, a 130°.
Sporoplasm within stylus, ~130um long.
seawater(Fig. 5B). Polarcapsules(8-1 1umlong) REMARKS. The thick stylus and arms are
remain at anterior end ofspore; valve cells form reminiscent of Siedleckiella Janiszewska, 1955
elongated stylus and 3 caudal processes. Spore but spores of Triactinomyxon type 2 did not
body (polarcapsules plus sporoplasm) 32-44um appear interconnected either inthe pansporocyst
long (34u.m, n=20) (Fig. 6C) and total spore orin seawaterand amis ofSiedleckiellaare blunt
length 208-268jam (236u.m, n=20). Caudal rather than pointed. Triactinomyxon type 2 is
processes, 240-360(am long (296um, n=46), largerthananyknownTriactinomyxon.Thearms
curve slightly anteriorly, taper to point, a 90°. ofT. magnum Granata, 1923 are>500um but the
Suture lines visible, germ cells indiscernible. stylus is only 25-30u.m long. The size of the
sporoplasm suggests it contains numerous germ
REMARKS. Triactinomyxon type 1 closely cells. Development is asynchronous. Spores
resemblesTriactinomyxonofRoubaletal., 1997, were liberated from pansporocysts under
except it is twice the size. When compared to pressure. This form was observed on only one
othertypes (Marques, 1984 [8types]; McGeorge occasion andthe host worm disintegrated during
et al., 1997 [1 type]; Xiao & Desser, 1998a [6 observation underthe cover slip.
types]; El-Mansy et al., 1998b, c [9 types]), Phylum APICOMPLEXALevine, 1970
including those invol&ved in a myxosporean life Order EUGREGARINORIDA Leger, 1900
cycle (El-Matbouli Hoffmann, 1989, 1993,
1998; Kent et al., 1993; El-Mansy & Molnar, Merogony absent; gametogony and sporogony
1997a, b; El-Mansy et al., 1998a; Szekely et al., present; typically parasites of annelids and
1999; Eszterbauer et al., 2000), Triactinomyxon arthropods, but some in other invertebrates.
MLMOIRS OF THE QUEENSLAND MUSEUM
FIG 6. |riactinomyxonspores. Fresh unstained material. A, IriactinomyxonofRoubal etal.. 1997 spores in sea
water. Scale I25(am. B. prominent polarcapsules of Iriactinomyxon ofRoubal et al.. 1997 spores within
pansporocystsdevelopingin theintestineofan oligoehacte. Scale=20um, C,anteriorend ofTriactinoroyxon
type 1 nov. spore in seawater showing polar capsules and sporoplasm. Scale ~= 20um. D, intestine v\'
limnodriUridine oligochaete distended with developing stages ofTrjactinoniyxon ofRoubal el al., 1997. Left
side uninfected, right side is Riled with pansporoblasts. Scale =200u.ni.
Family MONOCYSTIPAE Biitschli, 1882 Oligochaerocvstis sp.
(Fie. 8")
Gamonts spherical to cylindrical, withanterior
end little differentiated ifatall;oocysts biconical
ornavicular; mostlycoelomie; thegreatmajority IIDSI. Immature tubificid oligochaete.
are parasites ol'oligochaetes.
SITE IN MOST. All stages coelomie. SeveraJ gamonts
Genus Oligochaelocystis Meier, 1956 ap|x\ared attached to the oligochaete intestine by their
anterior ends. Infection extended from anterior region to
middleofoligochaete.
Gamonts club-shaped, solitary or in syzygy;
s_\ zygy head-to-head[type-species; 0.pachydrili LOCALITY!BoggyCreek, H*2A% l53DoyE
(I.ankester, 1863) Meier, 1956 emend. Levine.
1977]. SPECIMEN LODGED. QM G462725 (^147).