Two new freshwater crabs in Australocarcinus Davie, with remarks on Trogloplacinae Guinot and Goneplacidae Macleay (Crustacea: Decapoda: Brachyura)

11 Pages·1996·4.5 MB·English

TWO NEW FRESHWATER CRABS INAUSTRALOCARCINUSDAVIE, WITH
REMARKS ON TROGLOPLACINAE GUINOTAND GONEPLACIDAE MACLEAY
(CRUSTACEA:DECAPODA:BRACHYURA)
PJ.R DAVIE&D. GUINOT
Davie,P.J.F.&Guinot,D. 19960720:TwonewfreshwatercrabsmAustralocarcinusDavie,
with remarks on Trogloplacinae Guinot and Goneplacidae Macleay (Crus-
tacea;Decapoda:Brachyura).MemoirsoftheQueenslandMuseum39(2):277-287.Brisbane.
ISSN 0079- 8835.
Two new species,A. kanaka and A. palauensis, ofthe previously monotypicAustralocar-
cinus Davie are described from New Caledonia and Palau Islands, respectively. The three
species are separated on dentition ofthe anterolateral margins. Direct development ofthe
young without free-living stages isconfirmed forA. kanaka. Australocarcinusis placed in
the previously monotypic almost completely freshwater Trogloplacinae Guinot which is
restricted to the tropical West Pacific. Their apparent closest relatives are marine, mostly
deepwater Chasmocarcininae Serene (Gonoplacidae). Trogloplax has strong troglobitic
adaptations and is presumed to have evolved from anAustralocarcinus-Wke ancestor. The
TrogloplacinaeisseparatedfromtheChasmocarcininaebystructureoftheantennularregion,
and differences in length and shape of the male gonopods. Brachyura, Goneplacidae,
Australoplax, Trogloplax,freshwater.
PJ.F. Davie, Queensland Museum, P.O. Box 3300, South Brisbane, Queensland 4101,
Australia; D. Guinot, LahoratoiredeZoologie(Arthropodes), Museumnationald'Histoire
naturelle, 61 ruede Bujfon, Pariscedex05, France; 15April 1996.
Trogloplax Guinot, 1986, was erected for a Thisdiscovery,therecordsfromfreshwaterofthe
freshwatertroglobitic crab from New Britain. Its New Caledonian speciesandtheconfirmation of
type, T. joliveli, has a remarkable appearance, directdevelopment, show thattrogloplacines are
blind,andwith manyadaptivefeaturesforacave a very old freshwater group, probably derived
A
environment. Because of its many peculiar fea- from a marine ancestor, with at least riparius,
&
tures Guinot (1986) erected the Trogloplacinae, showing estuarine tolerance. Jamieson Guinot
in the Goneplacidae forit. (1996) examine the ultrastructure of the sper-
AustralocarcinusDavie, 1988, wasestablished matozoan of A. riparius and discuss possible
for a north Queensland estuarine species, A. generic relationships.
riparius Davie, 1988, also peculiar in the com- Abbreviations used in the text: c.b.=carapace
bination of morphological characters, in par- width; Gl,G2=male first and second gonopods;
ticular the unusual sternal plate, gonopods, and MNHN, Museum national d'Histoire naturelle,
putative directdevelopmentofthe young. Paris; QM, Queensland Museum, Brisbane;
While Trogloplaxshared the unusual structure SMF, Senckenberg Museum, Frankfurt; USNM,
of male sternite 8, its strong troglobitic adapta- United States National Museum, Washington.
tions made it difficulttobe sureifthetwogenera Measurements given in the text are of the
werecloselyrelated.Closecomparisonshowsthe carapace breadth (measured at the widest point)
2 genera to be related in the Trogloplacinae. We followedby length.Legsegmentsweremeasured
providearedefinitionofthesubfamilyandbetter in a straight line to give maximumdorsal length,
understanding of its relationships within the and so are not always the maximum possible
Goneplacidae. length.
Twoadditional speciesofAustralocarcinusare
described herein. One comes from a freshwater SYSTEMATICS
stream in northern New Caledonia and the
second, from Palau, was discovered by P.J.F.D.
amongstanunidentifiedcollectionofgrapsidson Family GONEPLACIDAE MacLeay, 1838
loan from the USNM to Michael Tiirkay at the subfamily TROGLOPLACINAEGuinot, 1986
Senckenberg Museum, Frankfurt. Also a large
population ofA. ripariusfrom a freshwater rain- Trogloplacinae Guinot, 1986:307; 1987:25; 1988:22;
forest stream in north Queensland is reported. 1994:167; Guinot&Geoffroy, 1987:18.
278 MEMOIRS OFTHEQUEENSLANDMUSEUM
FIG. \.Australocarcinuskanaka sp. nov., 9 paratype, 11.1 x 9.5 mm (QMW21389), dorsal view. Scale linein
mm.
DIAGNOSIS (emended from Guinot, 1986). of the male sexual opening (Guinot, 1978,
Carapace rounded; sometimes poorly calcified; 1979a).
anterolateral margin cristate, entire or toothed;
frontwithorwithoutshallowmedianindentation, AustralocarcinusDavie, 1988
without latero-external notch. Eyes relatively
small. Antennules folded completely into fosset. AustralocarcinusDavie,1988:259.
Antenna lying in orbital hiatus. Buccal frame
quadrangular; third maxilliped wide, togetheral- TYPE SPECIES. Australocarcinus riparius Davie,
most completely closing buccal cavity; exopod 1988, by originaldesignation.
broad, with flagellum. Sternal plate very broad,
with all sutures interrupted; large part ofsternite DIAGNOSIS. Carapace smooth, glabrous,
8 exposed; a supplementary transverse suture in regions poorly defined; anterolateral margins
middle ofsternite 8, parallel to suture 7/8, form- convex, with or without rounded teeth,
ing a supplementary plate. Sterno-abdominal posterolateral marginssubparallel,posterolateral
cavity deep. Male abdomen with segments 3-5 facet delimited. Frontal margin shallowly
fused. Abdominal locking mechanism in normal sinuous, formed of2 rounded lobes, moderately
position. Vulvaeoffemale very large, occupying deflexed, without preorbital lobes or teeth; fron-
position near extremity of sternal suture 5/6. to-orbital borderc. 0.5-0.6timescarapace width.
Penis very long, lying in covered channel on Orbits small, unarmed, with slightly raised rim.
sternite 8, only uncovered nexttothe coxaofP5; Eyestalks short, moveable, with well developed
finally protruding as long soft papilla. Chelipeds corneas; completely retractable within orbit.
with minor heterochely and heterodonty. Gl Chelae robust, similar but one slightly larger.
stout, moderately tapering, with an apical aper- Legs long, slender, hirsute, second pair longest.
ture; G2 about as long as Gl, with flagellum Maleabdomenwithsegments3-5fused,segment
about same length as peduncle. 3 expanded laterally, subequal in width to seg-
ment one, neithercovering sternumbetween last
REMARKS. The Trogloplacinae belong to the pair of legs. Sternal segment 8 in male with a
Heterotrematashowingacoxosternaldisposition closed, invaginated channel carrying penis, such
6
TWONEW FRESHWATERCRABS INAUSTRALOCARCINUS 279
FIG.2.Australocarcinuskanakasp.nov., 9 paratype, 1 1.1 x9.5mm(QMW21387),showinghatchedmegalopae
underthe abdomen. Scale line in mm.
that appears to be formed of 2 discrete plates; Australocarcinuskanaka sp. nov.
female ofnormal form. Gl stout, straight, taper- (Figs 1-4, 6, 8)
ing to simple apex; G2 as long as first, slender,
narrowed in width over distal half, ending in MATERIAL EXAMINED. HOLOTYPE
simple apex. MNHNB25279, 6* (11.1x9.5mm),Cold'Amoss,near
Ou6goa, New Caledonia, in freshwaterstream, 100m
altitude, 13.11.1993, R. Raven. PARATYPES
AustralocarcinusripariusDavie, 1988
QMW21387, 9 withmegalopae(11.1x9.5mm),data
(Fig- 7) asforhoIotype.QMW21388, 3 (10.5x9.0mm),29 9
(12.0 x 10.0; 13.1 x 10.8 mm), data as for holotype.
AustralocarcinusripariusDavie, 1988:260, figs 1-3. QMW21389, 9 (11.1 x 9.5 mm), 6 (6.4 x 5.5 mm),
Col d'Amoss, nearOuegoa, New Caledonia, infresh-
MATERIAL EXAMINED. QMW18234, \26 waterstream, lOOmaltitude, 13.05.1984,G.Monteith
(8.3x6.7-12.9x10.2 mm), 29 9(10.2x8.2, 11.3x and D. Cook. QMW20577, <J (3.6 x 3.1 mm),
9.5mm), MclvorRiverat Isabella-Mclvorroad cross- Ouekoula, near Ouemou, upper drainage of the
ing, 15°07.2'S, 145°04.4*E, freshwater,underrocksin OuemouRiver(drainingtothewestcoast),smalltrick-
ppopoml,sailntidtruydiencg.r3i0vmer,b1e8d.,11f.r1in9g9i2n,gPr.aiDnafvorieest&, DJ.OS2ho0rt..9 lP.esBooriugcihnaettin.gMfNrHoNm-sBe2e5ps2,8203,02m9 a9lt(i1tu1d.e2,x193..20;7.1129.943x,
10.4 mm), Pangou, upper drainage of the Ouaieme
DESCRIPTION. See Davie (1988). River (draining to the east coast), in wet mosses in
splash zone ofvery small stream forming rapids, 300
HABITAT. Freshwater and estuarine. The col- (m8.a7ltxit7u.d3e,mm1)3.,07O.u1£9n9e3\,nPe.aBroPuacnhgoeut,.uMpNpHeNrBd2r5ai2n8a1g,eo6f
lection site at the Mclvor River, is within rain- the Ouaieme River, seepage and small trickle, under
forestatabout30m altitude,and they were found dense secondary vegetation, 400 m altitude,
under rocks in pools in the drying river bed. 14.07.1993, P. Bouchet. MNHNB25282, 366 (3.5 x
Previous records were from estuaries where it is 3.0;4.0x3.6;7.5x6.2mm),29 9 (7.2x6.3;8.4x7.2
apparently common in salinities up to 20 p.p.t. mm), Koumac, 3 Creeks, NewCaledonia.
(Davie, 1988). DESCRIPTION. Carapace subrectangular;
greatestwidthbehindexorbital angles; 1.16-1.17
DISTRIBUTION. This record extends the dis- times broader than long. Carapace convex
tribution 400km further north along the eastern anteriorly, flat from side to side posteriorly,
Australian coast, from the Murray River, near slightly convex anteriorly. Regions poorly
Cardwell, and Hinchinbrook Island. defined, cardiac and metagastric regions defined
280 MEMOIRS OFTHEQUEENSLAND MUSEUM
FIG. 3.Australocarcinuskanakasp. nov. A-C, F, 9 paratype, 1 1.1 x9.5 mm. D, E,G, 6 paratype,6.4x5.5mm
(QMW21389).A,rightsideofcarapaceindorsalview.B,dactylusofthirdmaxillipedshowingstoutcomb-like
setae. C, third maxilliped. D, sternum ofmale. E, male abdomen. F, right chela. G, sternites 7 and 8 ofmale
showing fissureto form asupplementary plate.
TWONEW FRESHWATER CRABS INAUSTRALOCARCINUS 281
surface evenly punctate, smooth, naked, long
feathered setae restricted to side walls. Upper
orbital border smooth; moderately concave.
Lowerorbital borderstraight, slightlyconcave at
inner end; smooth. Inner angle of lower orbital
bordereffaced, reaching about halfway upbasal
antennal segment; lower orbital border con-
tinuous with loweredge ofouterorbital tooth as
aslightlyraisedrim. Antennalflagellumentering
orbit c.1.5 times length of orbit. Orbital hiatus
open. Basal antennal segmentshort, nottouching
front; unarmed. Inter-antennularseptumnarrow.
Third maxilliped with merus and ischium sub-
equal. Merusslightly widerthan long;outermar-
gin straight; antero-external angle not produced,
broadly rounded; about equal in length to is-
chium. Suture between merus and ischium
horizontal. Ischium quadrate; inner margin
smooth. Palparticulatingatinnerdistalmarginof
merus; relatively long,dactylusarmedwithlong,
stout, comb-like bristles apically. Exopod
moderately broad.
Chelipeds subequal, right slightly the largeron
holotype; large and robust; borders granulate;
row of longer feathered setae on anterior and
posterior borders; carpus with a broad spine at
inner angle. Outer surface ofpalm smooth, with
coarse punctations. Outersurfaceofpalmnaked.
Innersurfaceofpalm smooth. Immovablefinger
moderately long;flattened onoutersurface; with
a broad, shallow, longitudinal groove, bearing
close cropped setae; length cutting edge c. 0.4
times length propodus. Ventral border of chela
straight. Dorsal surface of dactyl smooth,
rounded; distal third ofdactyl with broad groove
like fixed finger. Fingers pointed, slightlycurved
inwards; a narrow gape between cutting margins
FIG.4.Australocarcinuskanakasp. nov., 6 holotype, proximally.
11.1 x 9.5 mm, QMW20577. A, gonopod 1. B, Walking legs relatively long, compressed,
gonopod 2. Scale line =0.5 mm. slender; second pair the longest. Longest leg c.
1.8-1.9 times maximum carapace width. Merus
by shallow grooves; posterolateral facet
of third leg c. 3.7-4.25 times as long as wide
delimited from behind last anterolateral tooth. (paratype and holotype respectively); carpus c.
Lateral marginssubparallel, orslightly divergent 2.7-2.8timesaslongaswide;propodusc. 2.5-2.7
posteriorly; straight. Anterolateral margins times as long as wide; dactylus c. 1.5-1.6 times
regularly convex; cristate; with two teeth behind length of propodus. Dactyli cylindrical, densely
theexorbital angle. Exorbital angleeffaced. First covered in felt of setae; terminating in acute
anterolateral tooth blunt, placed about halfway chitinous tips. Anterior margin of merus with a
along anterolateral margin. Second anterolateral subdistal shoulder; unarmed terminally. Legseg-
tooth blunt; similar in size to first in small male ments smooth; fringed with short, feathered,
but less obvious on holotype. Front moderately setae, longeron infero-distal borders ofpropodi.
deflexed; with or without shallow median emar- Male abdomen moderately broad; 5 free seg-
gination; lateral angles rounded; no pre-orbital ments; 3-5 fused; 1 and 3 widest, subequal. First
teeth; lateral marginsdivergingposteriorly; fron- segment not covering entire width of sternum
to-orbital border c. 0.5 times width. Carapace between 4th pereiopods; narrow. Segments 3-5
282 MEMOIRSOFTHEQUEENSLAND MUSEUM
^^-
^*to ^ ;
. . *
FIG. 5.Australocarcinuspalauensissp. novM 9 holotype, 7.1 x 5.8 mm (USNM). A. carapace in dorsal view.
B, thirdmaxilliped.C, leftchela. D, abdomen. Scaleline = I mm.
tapering, basally bulbous. Segment 6 c. 2 times (7.1 x5.8 mm), AddeidoRiver, insmall fasttributary,
wider than long. Telson longer than penultimate BabclthuapId., Palau Islands,05.03.1946, D.S. Frey.
segment; c. 0.8 times longer than wide; apically
rounded. Male gonopods Fig. 4. Sternum broad. DESCRIPTION. Carapace subrectangular;
greatestwidthbehindexorbitalangles; 1.22times
HABITAT. Freshwaterhabitats in a freshwater broader than long. Carapace convex anteriorly,
stream; in small trickles originating from seeps; flat from side toside but slightly convextowards
inwetmossesinsplashzoneofverysmallstream the margins. Regionspoorlydefined,cardiacand
formingrapids; and in seepageand small trickles metagastrie regions indistinctly defined;
under dense secondary vegetation. Recorded up posterolateral facet not defined. Lateral margins
to400m above sea level. subparallel; straight. Anterolateral margins
regularly convex; cristate; without teeth. Exorbi-
ETYMOLOGY. A noun in apposition for the native tal angle effaced. Front moderately deflexed;
peoplesoftheislandsoftheSouth West Pacific. bilobed; lateral angles rounded; no pre-orbital
teeth;lateral marginsdivergingposteriorly;fron-
Australocarcinuspalauensis sp. nov. to-orbital border c. 0.55 times carapace width.
(Figs 5, 8) Carapace surface evenly punctate, smooth. Dor-
sal surface naked, long feathered setae on side-
MATERIAL EXAMINED. HOLOTYPE USNM, 9 walls. Upper orbital border smooth; moderately
TWONEW FRESHWATERCRABS INAUSTRALOCARCINUS 283
oflong feathered setae on anterior and posterior
borders; carpus withabroad, blunt spine atinner
angle. Outersurfaceofpalmsmooth, withcoarse
punctations; naked. Inner surface of palm
smooth. Immovablefingermoderatelylong,flat-
tened on outer surface; without obvious lon-
gitudinalgroove. Lengthcuttingedgec.0.4times
length propodus. Ventralborderofchelaslightly
concaveatbaseoffixedfinger. Dorsalsurfaceof
dactylsmooth,rounded.Fingerspointed; slightly
curved inwards; a narrow gape between cutting
margins proximally, fingers with teeth poorly
differentiated, but large, backwardly directed
molar near base ofdactyl.
Walking legs relatively long; compressed;
slender; second pair the longest, c. 1.8 times
maximum carapace width. Merus ofthird leg c.
3.5 times as long as wide; carpus c. 2.6 times as
long as wide; propodus c. 2.4 times as long as
wide; dactylus c. 1.4 times length of propodus.
Dactyli cylindrical, densely covered in a felt of
setae; terminating in acute chitinous tips.
Anterior margin of merus with subdistal
shoulder; unarmed terminally. Leg segments
smooth; fringed with short, feathered setae,
longeron infero-distal borders ofpropodi.
HABITAT. From a fast flowing tributary ofthe
Addeido Riversuggesting a freshwaterhabitat.
ETYMOLOGY. Forthe Palau Islands.
FIG. 6. Australocarc'mus kanaka sp. nov., megalopa REMARKS ONAUSTRALOCARCINUS
(QMW21387). Pleopodal membrane still attached
around baseoftelson. Scale line =0.5 mm. DAVIE
The three known species are very similar but
concave.Lowerorbitalbordershaliowlysinuous; differ conspicuously by the dentition of the
smooth; inner angle effaced, reaching about anterolateral margins.Australocarcinusriparius
halfway up basal antennal segment; continuous has4 large, prominentblunt teeth;A. kanaka has
withloweredgeofouterorbitaltoothasaslightly only 2 low, hardly projecting, blunt lobes; andA
raised rim. Antennal flagellum entering orbit; palauensishas no anterolateral teeth, but simply
both flageilums missing. Orbital hiatus open. a continuous crest. The telson of A. kanaka is
Basal antennal segmentshort, nottouching front, much shorterthan onA. riparius.A. ripariusalso
unarmed. Inter-antennularseptum narrow. differs from the other two species by having the
Third maxilliped with merus and ischium sub- outer margin ofthe merus ofmaxilliped 3 much
equal. Merus wider than long; outer margin more strongly convex.
slightly convex; antero-external angle not Davie (1988) speculated that direct develop-
produced, broadly rounded; c. 0.85 times length ment occurred inA. riparius because 18juvenile
of ischium. Suture between merus and ischium crabs were collected with the adult female. This
horizontal. Ischium quadrate; inner margin reproductivestrategyhasnowbeenconfirmedfor
smooth. Palparticulatingatinnerdistal marginof A. kanaka as one female (QMW21387) has 17
merus; relatively long,dactylusarmed with long, megalopae still attached to its pleopods (Figs
stout, comb-like bristles apically. Exopod 2,6). The megalopae have no obvious yolk
moderately broad. reserve. Ovigerous females ofA. riparius carry
Chelipeds slightly unequal, right slightly the about 70 eggs, so there seems to be significant
larger; large and robust; borders granulate; row attrition during the developmental stages. The
284 MEMOIRS OFTHEQUEENSLANDMUSEUM
LV
w
interrupted, and with ster-
nite 8 broadly uncovered.
II [Suturewithsternite 7 5) the Gl is stout and
| straight,andwithanapical
ThoraxT opening. 6) the G2 is sub-
feM equal in length to Gl, and
with the two parts (flagel-
Vi Opening lum and peduncle) sube-
1
forpenis qual in length. 7) the male
^i^H^^l^ Invaginated canal in sternite 8 p abdomen has segments 3-
5 fused. 8) the sterno-ab-
dominal cavity is deep in
the male. 9) there is feeble
heterochely and feeble
heterodonty. 10) the an-
tenullar flagellae fold
transversely into fossae
r 1mm under the frontal margin.
Posterioredge ofsternite 8 |
11) a sternal crest sur-
rounds the telson of the
FIsGc,an1n.iAnugstelreacltorcoanrcmiincursogrripaaprhiuosfDtahveiei,nsi1d9e88of(sdt,er1ni1t.e68m,mshco.wb.i,nQgMiWn1va8g2i3na4t)e,d mStaelren.ite128) tihsecooumteprosfaecde ooff
channel in which the penis lies. two plates separated by a
suture which marks an
A
holotypefemaleof palauensisalsoshowslarge medial invaginated canal,
vulvalopeningsandthereforedirectdevelopment in which the penis lies.
can similarly be inferred forthis species.
REMARKS ON THEGONEPLACIDAE
RELATIONSHIPOFAUSTRALOCARCINUS
AND TROGLOPLAX
Guinot (1969a,b,c, 1971) showed that the
Goneplacidae MacLeay, 1838, sensu Balss
Many of the most unusual characteristics of (1957)constitutesanheterogeneousassemblage,
monotypic Trogloplax (Guinot, 1986, 1987) and must be re-appraised. Evolutionary lineages
(type T. joliveti), can be attributed to its caver- in the family are the goneplacine (=car-
nicolous adaptations. These are common, to a cinoplacine)line,apilumnineline,thepanopeine
greater or lesser extent, in all cave dwelling line, and the euryplacine line. The Geryonidae
arthropods. They are: 1)the soft, poorlycalcified were considered very distant from the
carapace; 2) dorsoventral flattening; 3) the Goneplacidae. The Rhizopinae Stimpson, 1858,
reduced narrow eyestalks with the corneas lack- still needs to have somequestions resolved. This
ingfacetingandpigment(Guinot, 1988,fig. 16A- subfamily may need to be restricted to the type
C);4)thelossofpigmentationofthecarapaceand species,R. gracilipes Stimpson, 1858, whichap-
pereiopods; 5) exceptionally elongated and thin pears to constitute a separate lineage, a little
pereiopods,especiallytheambulatorylegs;6)the different from the pilumnine line (sensu stricto)
two long spines of the chelipeds. (Guinot, because the male Gl, while similar, is not of
1986:165). typical pilumnid form with the stronglyrecurved
Despite strong superficial differences there are tip (Guinot, 1969a, fig. 1 10), but the G2 is effec-
fundamental characters that mark a close tively the same as in the Pilumnidae. Ng (1987)
relationship between Trogloplax and reviewed the constitution ofthe Rhizopinae, and
Australocarcinus: 1) the carapace lacks setae, is itappearsthat all thegenerahe included havethe
rounded, and the anterolateral borders are Gl with a pilumnine recurved tip, and the short
anteriorly converging and cristate. 2) the buccal sinuousG2 alsotypicalofpilumnids. Wethink it
cavity is large and quadrangular. 3) the maxi- possible that the Rhizopinae (sensu Ng, 1987)
llipeds are short and broad, with the exopods may still be heterogeneous with Rhizopa itself
relatively broadand with aflagellum. 4) the ster- forming a separate lineage. Ifthis is so, then the
nal plate is broad with the sutures 4/5 to 7/8 name Typhlocarcinopsinae Rathbun, 1909, is
TWO NEW FRESHWATER CRABS INAUSTRALOCARCINUS 285
availableforTyphlocarcinopsand perhaps some hasanopensutureinsternite8,suchthatthepenis
other genera. Typhlocarcinops has gonopds that is visible. Glaessner & Secretan (1987) and
are not ofihe classical pilumnid type (sensu Ng, Tavares (1992) described exactly such a condi-
1987). tion for the fossil American Eocene crab Fal-
We consider that primitive goneplacid genera conoplax Van Straelen, 1933. This genus had
of the pilumnine line cannot be separated been attributed to the Tymolinae' by Glaessner
phylogenetically from the xanthoid Pilumnidae (1969)(= Cyclodorippidae), but Tavares (1992)
(Pilumnus). In the same way the panopeids Cyr- re-attributedthis fossiltotheGoneplacidaesensu
toplaxRathbun, 1914, TetraplaxRathbun, 1901, lato,agreeingwithVanStraelen1s(1933)original
We
Glyptoplax Smith, 1870, and Cycloplax Guinot, placement. believe thatFalconoplaxbelongs
1969, etc., cannot be separated phylogenetically to the Chasmocarcininae. The first record of a
from the panopeids like Panopeus H. Milne Ed- fossil Chasmocarcinus was reported from the
wwahridcsh,t1h8e3n4a,mbeutEuthceryatfooprsminaaneaStturiamlpsgorno,up1i8n7g1f(o=r (EFoeclednmeaonfnAn&taZricntsimceai,sitners,ha1l9l8o4w).watersediments
Prionoplacinae Alcock, 1900) may be used. Serene (1964a), with some reserve, placed
The Goneplacidae contains the Goneplacinae MegaesthesiusRathbun, 1909,intheChasmocar-
We
Miers, 1886, Carcinoplacinae, Miers, 1886, cininae. exclude it from the subfamily but
Chasmocarcininae Serene, 1964, Trogloplacinae acknowledge its relationships must be inves-
Guinot, 1986, and the Euryplacinae Stimpson, tigated further.
1871. Many genera are still not satisfactorily Inspiteofthesimilarity inthecoxosternalplate
placed in these subfamilies and a revision is ur- between the Trogloplacinae and the Chasmocar-
gently needed. cininae, there are some notable differences. The
majordifference is that in theChasmocarcininae
AFFINITIES OF THE TROGLOPLACINAE. the basal antennularsegment is very swollen and
Themostrevealingcharacterin helpingtounder- completely fills the antennular fosset, such that
stand the affinities of the Trogloplacinae is the the flagellum is excluded and cannot be folded.
disposition ofthe penis and gonopore. Typically The gonopods ofthe two subfamilies are similar
incoxosternalcrabs(sensuGuinot, 1978, 1979a), in that the Gl is stout and tapering and the G2 is
theejaculatorycanalopenson thecoxaofP5 and long and not sigmoid, however there are also
there is a long penis sometimes visible near the differences. In the Chasmocarcininae the G2 is
aperture on the coxa but with most of its length noticeably shorter than the Gl and the flagellum
covered by the complete junction of sternites 7 is short (length varies a little depending on the
and 8 and with the distal part long and emerging species). In the Trogloplacinae the G2 is as long
to enter the base of the Gl (Guinot, 1979a, fig. orslightly longerthan the Gl, and the flagellum
5IF; 1979b, figs 2,3). Sternite 8 of the Troglo- occupiesabouthalforslightlymoreofthelength.
placinae hasan invaginatedchannel in which the Considering the close relationships with the
penis lies (Fig. 7). exclusively marine Chasmocarcininae, and the
The Trogloplacinae as Guinot (1986) has al- presenceofatleastoneestuarine tolerantspecies
ready indicated,belongstotheGoneplacidaeand inAustralocarcinus,derivationofthecompletely
is most closely related to the Chasmocarcininae freshwater Trogloplax from a marine stock is a
Serene, 1964(ChasmocarcinusRathbun, 1898)a logical assumption.
marine, mostly deepwater group (Serene,
1964a,b). All Chasmocarcininae (Chasmocar- BIOGEOGRAPHY.Thetrogloplacinesaresofar
cinus, Camatopsis Alcock & Anderson, 1899, only known from the western Pacific (Fig. 8).
Chasmocarcinops Alcock, 1900, Hephthopella Trogloplax occurs in two freshwater subter-
Alcock, 1899, Scalopidia Stimpson, 1858) have ranean caves on New Britain, PNG (Guinot &
gthreoopveeniisn sltyeirnngitein8ei(tFheelrdearn&enRcalboesleaids,or19o8p6e)n, Gaenodfftrhoeyc,ra1b9s87)w.erTehefotuwnodca3v0e0smarein2t5o0tkhemcaapvaerst.,
such that sternite 8 has an intercalated plate Australocarcinus is now known from three
anteriorly, a fact first observed for Chasmocar- speciesinnorthQueensland,NewCaledonia,and
cinusby Rathbun (1914). Palau; itseemsprobablethatotherspecieswillbe
The type species ofHephthopelta (H. luguhris foundon theWestPacific Islands. Althoughlittle
Alcock) is a female, and not well known, but a is known of the reproductive patterns of the
new species ofHephthopelta we have examined trogloplacines, Davie's (1988) supposition of
(being described by Davie & Richer de Forges) directdevelopmentforAustralocarcinusriparius
286 MEMOIRS OFTHEQUEENSLANDMUSEUM
Caledonia, and made valuable comments on the
150°E manuscript. Philippe Bouchet of the Museum
national d'Histoire naturelle, Paris, collected
many specimens from inaccessible places. Peter
Ng, National UniversityofSingapore,isthanked
for his thorough review ofthe paper.
New Britain
LITERATURECITED
ALCOCK, A. 1899. An account of the deep-sea
Queensland M \ Brachyura collected by the Royal Indian Marine
New Caledonia Survey Ship 'Investigator*. (Calcutta). 86p.
1900. Materials foracarcinological fauna ofIndia.
No. 6. The Brachyura Catametopa, or Grap-
soidea. Journal ofthe Asiatic Society ofBengal
..-' sP)> ALCO6C9K(,Pt.A.2,W.No&.A3)N:D2E79R-S4O56N.,A.R.S. 1899.Natural
history notes from H.M. Royal Indian Marine
Survey Ship 'Investigator', Commander T.H.
FIG. 8. Distribution ofAustralocarcintts and Troglo- Heming, R.N., commanding. Ser, III, no. 2. An
plax. Star =A. palauensis sp. nov.; hollow box =A. accountoftheDeep-seaCrustaceadredgedduring
kanaka sp. nov.; solid circle = A. riparius Davie, the surveying season of 1897- 1898. Annals and
1988; diamond = TrogloplaxjolivetiGuinot, 1986. MagazineofNatural History3: 1-27, 278-292.
BALSS, H. 1957. Decapoda. Dr. H.G. Bronns Klassen
has been confirmed for A. kanaka. If the other und Ordnungen des Tierreichs Funfter Band (I
species ofAustralocarcinus and Trogloplaxalso Abt, 7 Buch, 12): 1505-1672, figs 1131-1199;
have direct development, this should reinforce (Buch. 13): 1673-1770, figs 1200-1212.
their allopatric distributions and contribute to DAVIE, PJ.F. 1988. A new genus and species of
small area speciation. One factor which could goneplacid (Crustacea: Brachyura) from
Queensland, Australia. Memoirs of the
allow genetic interchange overa limited range is Queensland Museum 25(2): 259-64.
the high salinity tolerance exhibited by A. FELDER, D.L. & RABALAIS,N.N. 1986.Thegenera
riparius, which allows it to survive under es- Chasmocarcinus Rathbun and Speocarcinus
tuarine conditions. Estuarine corridors along the Stimpson on the continental shelfofthe Gulfof
coast between riversystems, during flood condi- Mexico, with descriptions of two new species
tions, could allow dispersal of adults and the (Decapoda: Brachyura:Goneplacidae).Journalof
maintenance of the species over long distances, Crustacean Biology 6(3): 547-575.
asoccurson theNEcoastofQLD. Suchadisper- FELDMANN. R.M. & ZINSMEISTER, W.J. 1984.
sal method however is only likely to be of local New fossilcrabs(Decapoda: Brachyura)fromthe
importance.Thereseemstobenoobviousdisper- La Meseta Formation (Eocene) of Antarctica:
sal orvicariantexplanation thatconveniently ex- paleogeographicandbiogeographicimplications.
plains the observed distribution patterns of the Journal ofPaleontology 58(4): 1046-1061.
genera and species oftheTrogloplacinae. GLAESSNER,M.F. 1969.Decapoda.Pp.R399-533.In
Moore, R.C., (ed.). Treatise on invertebrate
ACKNOWLEDGEMENTS paleontology. PartR, Art&hropoda4(2), (Geologi-
cal Society of America Univ. Kansas Press:
Lawrence, Kansas).
We would like to acknowledge the help of a GLAESSNER, M.F. & SECRETAN, S. 1987. Crabes
number of people. Michael Tiirkay, (Crustacea Brachyura) de 1'Eocene du Sulaiman
ForschungsinstitutSenckenberg,Frankfurt,kind- Range (Pakistan). Annales de Paleontologic
ly gave PD access to loan material from the (Vert-Invert) 73(4): 273-88.
USNMinhiscare,amongstwhichwasfoundone GUINOT, D. 1969a-c. Recherchespreliminairessurles
of the new species. Clare Bremner and Alison groupements naturels chez les Crustaces
Decapodes Brachyoures. 7. 1969a, Les
HKiylllieexeSctuutmedkaFtigutroeosk3tahnedS5ErMespepchtoitveolgyr,apahn.d Goneplacidae. Bulletin du Museum National d'-
Bertrand Richer de Forges of ORSTOM, H1i9s6t9obi,reLeNsatuGroenlelpel,acPiadraise ((2su)i4t1e().1):Bul2l4e1t-in26d5u;
Noumea, New Caledonia, gave PD hospitality Museum National d'Histoire Naturelle, Paris
andstimulatingdiscussionduringhisvisittoNew (2)41(2): 507-528; 1969c, Les Goneplacidae