The Indo-Pacific Pilumnidae VII. Notes on Heteropilumnus sasekumari (Serène, 1971) and Cryptolutea Ward, 1936 (Crustacea: Decapoda: Brachyura)

8 Pages·1991·2.6 MB·English

by  P K L Ng

THE INDO-PACIFIC PILUMNIDAE VII. NOTES ON HETEROPILUMNUS
SASEKUMAR!(SERENE, \97\) AND CRYPTOLUTEA WARD, 1936 (CRUSTACEA:
DECAPODA: BRACHYURA)
PETER K.L.NG AND PETER DAVIE
J.F.
Ng, P.K.L. and Davie, P.J.F. 1991 08 01: The Indo-Pacific Pilumnidae VII. Notes on
Heteropilumnus sasekumari (Serene, 1971) and Cryptolutea Ward, 1936 (Crustacea:
Decapoda: Brachyura). Memoirs ofthe Queensland Museum 30(3): 517-524. Brisbane.
ISSN 0079-8835.
A redescnption ofthe poorly known pilumnid crab Heteropilumnussasekumari(Serene,
1971) is provided, including the first known males ofthe species. H. sasekumari is only
the second rhizopine species known to occur predominantly in mangroves, with a wide
range from Peninsular Malaysia to Borneo and northern Australia. Cryptolutea lin-
damenensis is redescribed and the genus rediagnosed. A primary diagnostic character is
the denticulated plateproducedfrom thecoxaofeach ambulatory leg.Serratocoxa Ng, is
considered a junior synonym of Cryptolutea Ward. Cryptolutea now contains C. lin~
C
demanensis Ward, C. sagamiensis (Sakai), granulosa (MacGilchrist), and C. teschi
(Serene). Crustacea,Brachyura, Pilumnidae, mangrove-dwelling, fndo-WestPacific.
Peter K.L. Ng, Department ofZoology, National University ofSingapore, Kent Ridge,
Singapore0511, RepublicofSingapore;P.J.FDavie, QueenslandMuseum, POBox300,
SouthBrisbane,. Queensland4101,Australia;25January, 1991.
The Indo-West Pacific pilumnid subfamily opportunity is taken here to describe the first
Rhizopinae Stimpson, 1858, is comprised of known males of Heteropilumnus sasekumari
small,usuallymud-dwellingcrabs,thatareoften from Australia.Thisspeciesisalso unusualwith
cryptic. Their taxonomy has been under exten- regard to its ecology - all specimens have been
sive review in recent years (Ng, 1987)but some recorded from mangroves and appear to prefer
problems remain to be resolved. In particular this habitat. Thiswould make it only the second
Cryptolutea Ward, 1936, has been poorly mangal rhizopinespeciesknown (seeNg, 1990).
known. Itwasincluded intheRhizopinaeforthe G1 and G2 indicate the male first and second
first time by Ng (1987) but he was unable to pleopods,respectively. All measurements areof
adequately diagnose it, and expressed some the carapace width and length, respectively.
doubts as to its validity. Specimens are deposited in the Queensland
Heteropilumnus sasekumari was originally Museum (QM) and Zoological Reference Col-
describedonthebasisofasinglefemalefromthe lection(ZRC),DepartmentofZoology,National
mangroves of western Peninsular Malaysia University ofSingapore.
under Rhizopa Stimpson, 1858, by Serene
(1971). Ng (1985) queried the placement ofthis Heteropilumnussasekumari (Serene, 1971)
species in Rhizopaand refigured thespecies. He (Figs 1,2)
alsoaddedanewrecord(afemale)from Labuan,
northernBorneo.Davie(1985)thenrecordedthe IRhizopasasekumariSerene, 1971: 915-16, PI. 5A.
species^sRhizopasasekumariin hischecklistof Rhizopa sasekumari: Guinot, 1971: 1078; Ng, 1985:
mangrove crabs from northern Australia. He in- 631, Fig. 2; Davie, 1985: 261, 262.
correctly recorded the species from Singapore. Heteropilumnussasekumari: Ng, 1987: 73, 79, 96.
Ng(1987)subsequentlytransferedthespeciesto
Heteropilumnus De Man, 1895, restricting MaterialExamined
Rhizopa toR. gracilipes Stimpson, 1858. HOLOTYPE: ZRC 1969.12.2.7, 6, littoral zone, Port
MalesofHeteropilumnussasekumarihavenot Swettenham, western Peninsular Malaysia, A.
previouslybeen collected. In view ofthe impor- Sasekumar, 28 Oct. 1968.
tanceofthemalegonoductpositions,formofthe Other Material: ZRC 1965.11.23.49-50, 29 2
,
male first pleopod, and structure of the male Prai, Province Wellesley, western Peninsular
abdomen in xanthoid and pilumnid taxonomy, Malaysia, Dec. 1938 (det. R. Serene, 1962). ZRC
518 MEMOIRS OFTHEQUEENSLAND MUSEUM
FIG. \. Heteropilumnussasekumari{S^rhw^,\91\).Md\^, 18.0 x 13.5 mm, Queensland (QM W4596).
1965.11.23.51, $, mangrove, Labuan, Sabah, Bor- nea distinct, pigmentation present. Basal anten-
QM
neo, 1938(del. R. Serene,6 Dec. 1969). W4596, nalsegmentmovable,fillingmostofwideorbital
<5, (18.0 X 13.5 mm). Trinity Inlet, C. 2.5 km from hiatus (Fig. 2A). Antennular fossae wide, oc-
mouth of Redbank Creek, Cairns, Queensland, R. cupying most of space below frontal margin,
Timmins, 13 Dec. 1974, QM W3852, <?, Calliope separated by very narrow gap. External orbital
River, SE Queensland, Australia, 4 Aug. 1978. QM angle well defined, broadly truncate, outer mar-
W7887, 9, Susan River, Hervey Bay, SE gin gently sinuous, inner margin very short,
Queensland, Australian Littoral Society, 24 Dec. separated from first epibranchial tooth by deep
1971. but narrow notch; firstepibranchial toothbroad-
ly triangular, inner margin halflength ofouter,
Description outer margin gently sinuous, separated from
Carapacequadrilateral,distinctlybroaderthan second epibranchial tooth by triangular notch,
long. Dorsal surface densely pubescent, with second epibranchial tooth triangular, curved
numerousscattered longhairs; pubescence does obliquelyforwards, innermargin concave,outer
not completely obscure indentation on distinctly convex, tip rounded, separated from
anterolateral margin. Frontal margin deflexed, thirdepibranchialtoothbydeepV-shapednotch,
dividedinto twogentlyconvexlobesby shallow thirdepibranchial toothtriangular,directedobli-
cleft,externalanglenotobvious. Orbitalmargins quelyoutwards,tipsharp.Posterolateralmargins
smooth, outer edges of supra- and infraorbital almost straight, distinctly converging towards
marginsseparatedbydeep,verynarrowincision. gently convex posterior carapace margin.
Eyes well developed, filling orbital space, cor- Posteriormargin ofepistome sinuous, distinctly
FIG. 2. Heteropilumnussasekumari (Serene, 1971). Male, 18.0 x 13.5 mm, Queensland (QM W4596). A,
frontal view. B, left third maxilliped (denuded). C, abdomen. D, left fourth ambulatory leg (denuded). E,
dactylus ofleft fourth ambulatory leg, lateral view. F, dactylus ofleft fourth ambulatory leg, dorsal view
showingcurvature. G, leftmale gonopore and penis (arrow). H, left Gl. I,J, distal partofGl. K, left G2.
INDO-PACIFICPILUMNIDAE 519
520 MEMOIRS OFTHE QUEENSLAND MUSEUM
cut into four lobes, incisions deep, distinct. En- Remarks
dostomial ridges not apparent. The transfer and retention of sasekumari in
Third maxillipeds occupying entire buccal Heteropilumnusremains provisional. Ng(1987)
cavity, merus quadrate, depressed medially, noted that Heteropilumnus is in urgent need of
margins cristate, outer distal margin distinctly revision; the characters used to characterise the
produced; ischiumwiderproximally than distal- genusbeinginadequate(NgandTan, 1988).The
ly, with deep median sulcus, inner margin with carapace provides the only reliable generic fea-
row of short stiff hairs, outer margin distinctly tures the shape (almost rectangular), and the
concave; exopod long, reaching external angle pattern of setae on the dorsal surface (a short
of merus, distal one third of inner edge with pubescence on the posterior parts of the
carapace, with much longer setae on the
truncated lobe, setoseflagellum long, extending anterolateral, supra-orbital, frontal regions and |
beyond width ofmerus (Fig. 2B).
frontalmargins).Several species in Pilumnus{s.
Chclipeds stout, usually right slightly larger.
lato)^ Cryptocoeloma, Viaderiana and Typh-
Outer surfaces covered with dense pubescence
locarcinus also appearto be verv closely related
and scattered long stiff setae. Distal posterior (Ng, 1987, 1989).
margin of merus with sharp tooth. Inner angle In the ZRCaretwo morefemales(notreported
of carpus with large low, blunt tooth. Median by Ng, 1985) of H. sasekumari (ZRC
parts of larger chela naked, smooth; pubescent 1965.1 1.23.49—50) from Prai. in Province Wel-
areas with numerous small granules; inner sur- lesley, northwestern Peninsular Malaysia, near
face rugose. Fingersdarkened almost to hooked the island of Penang. They had been identified
tip which is beige-coloured; cutting edges with bySerenebefore 1971,buthedidnotincludethis
5-6 large blunt teeth and several denticles; material in his original description. This record
fingers each with one low longitudinal ridge on thus extends the species' range further north.
outer surface; dorsal proximal part of dactylus Heteropilumnussasekumariisoneofonlytwo
with numerous small granules, pubescence, and pilumnids known tooccurpredominantly (ifnot
scattered longsetae (Ng, 1985: Fig. 2C, D). wholly)in littoralmangrove areas. Otherthan its
Ambulatorylegssetoseasoncarapace,second habitat, almost nothing else is known about its
biology and habits. The other known mangrove
leg longest, meri, carpi and propodi unarmed,
surfaces smooth when denuded, without spines pilumnid is the rhizopine, Luteocarcinus sor-
didus Ng, 1990, from western Peninsular
or tubercles. First to fourth dactyli long, gently Malaysia.
recurved,fifthdactylus,whenplacedhorizontal- {
ly, curves gently upwards (Fig. 2D-E). ;
Cryptolutea Ward, 1936
Maleabdomenwith seven segments, all freely I
articulating(Fig.2C). Firstmale abdominal seg-
ment reaching base of coxa of last pair of am- Cryptolutea'Ward, 1936: I {iype speciesCryptolutea
bulatory legs,secondlesswide, thirdhexagonal, lindemanensisWard, 1936, by monotypy). '
Cryptolutea: Guinot, 1969: 247; Ng, 1987: 87, 99.
fourth to sixth progressively less trapezoidal,
Serratocoxa Ng, 1987: 101 (type species Lophoplax
seventh triangular, lateral margins convex, tip
toe/?/Serene, 1971, by original designation).
rounded.
Gonopores coxal, penis reaching G1 via rela-
Remarks
tivelybroad,exposedgrooveformedbysternites
This poorly known monotypic genus con-
7 and 8 (Fig. 2G). G1 very slender, strongly tained C lindemanensis Ward, 1936, known
sinuous, distal part hooked downwards, lip very only from the holotype from Lindeman Island i
slender, tapering to sharp point (Fig. 2H-J). G2 offcentral Queensland. Ng (1987: 99) placed it I
very short, sigmoid, distal part dilated, inner in the Rhizopinae and expressed doubt on its
surfacedepressedintocup-likestructure,tipdis- validity, suggesting that C. lindemanensis may
tinctly produced, cup-like depression with be a synonym of Ceratoplax luteus. Elsewhere
numerousshort spines (Fig. 2K). in that paper (p. 101) he recognised a group of
species, Lophoplax teschi Serene, 1971,
Distribution Ceratoplax sagamiensis Sakai, 1935, and C.
Western PeninsularMalaysia; Labuan, Sabah, granulosa MacGilchrist, 1905, as being con-
Borneo; tropical and sub-tropical eastern generic and erected Serratocoxa, to receive
Queensland, Australia. them. Thishadearlierbeen suggestedby Serene
INDO-PACIFICPILUMNIDAE
521
FIG. 3. Cryptolutea lindemanensisWard, 1936. Male holotype (OMW744).
and Lohavanijaya (1973) who were first to Ward, 1936; C. sagamiensis (Sakai, 1935); C.
recognise on the posterior border of the am- granulosa (MacGilchrist, 1905), and C. teschi
bulatory legs of a denticulated wing-like plate (Serene, 1971).
covering the ischium’ on all three species.
On examination of the holotype of C. lin- Diagnosis
demanensis it was found that this species was Carapace distinctly quadrate, the anterolateral
both clearly distinctfrom Ceratoplaxluteus and marginarcuate,almostentire,orwithbluntlobes
alsoexhibited theremarkablewing-likeplateon more or less distinct. Anterolateral angle of
the coxa ofthewalkinglegs. Itiswithout doubt merus of third maxilliped produced. Coxa of
congenericwiththeotherspeciesincludedbyNg ambulatory legs with denticulated plate which
(1987)inSerratocoxaandthereforeSerratocoxa partially covers the ischium. First male ab-
Ng must become a junior synonym of Cryp- dominalsegmentbroaderthanthird,reaching,or
A
tolutea Ward, diagnosis is given here which almost reaching base of last pair ofambulatory
is only slightly modified from that given by Ng legs; male genital openings coxal, with penis
(1987) forSerratocoxa. exposed and lying in agroove between sternites
Cryptolutea now contains C. lindemanensis 7 and 8. G1 slender, sinuous; G2 short, sinuous.
522 MEMOIRS OFTHE QUEENSLAND MUSEUM
FIG. 4. CryptolutealindemanensisWard, 1936. Male holotype (QM W744). A, frontal view. B, frontal and
anterolateralmargin.C,tipofleftGl. D,leftGl.E,rightthirdmaxilliped.F,deformedleftthirdmaxilliped.
G, denticulated plateon the coxa offourth ambulatory leg. H, abdomen.
Cryptolutea lindemanensisWard, 1936 Description
(Figs 3, 4) Carapace quadrilateral, 1.27 times broader
thanlong. Dorsal surfaceglabrous,butedgedby
i
Cryptolutealindemanensis'^ 1936; 1-2,pi.1,figs a fringe of moderately long, soft setae, par-
1-3; Ng, 1987: 79, 99. ticularlyprominentacrossfrontal lobesandonto
ocular peduncles. Regional definition not ob-
MaterialExamined vious except for transverse gastro-cardiac
HolotypE: QMW744, 1(3(15.8 x 12.4 mm) Lin- groove, and associated short concave lon-
deman Is., Whitsunday Passage, ME.Queensland, gitudinal grooves. Frontal margin deflexed,
M.Ward. slightly concave viewed from front, laterally
roundedwithoutantennalnotches;frontalregion
with shallow, median, longitudinal groove so
INDO-PACIFICPILUMNTDAE 523
that front appears slightly bilobed from above. band of long setae on superior surface which
Supra-orbital borderminutelygranular,laterally extends onto dactylus for about its proximal
rounded to form first epibranchial lobe. Infra- third. Dactylus with longitudinal groove run-
orbital margin smooth; laterally rounded, ning most of its length. Both fingers darkened
without notches or incisions; blunt lobe at inner for approximately distal four-fifths, fingers
edge, reachinglevel ofdistal endofbasal anten- pointed; crossing at tips; evenly serrated. Fixed
nal segment. Ocular peduncles fill the orbital finger with longitudinal groove for most of its
space; not freely movable; corneas relatively length; with a few short setae in the groove.
small, not visible from above; distinct but not Outerfaceofchelanaked;smoothexceptfortwo
darkly pigmented in holotype. Basal antennal or three rowsoflow scattered tubercles near the
segmentmovable,innerdistalmarginjustreach- inferior margin; and a few granules proximally.
ing front. Antennular fossae wide, occupying Maleabdomenwithsevenfreesegments. First
mostofspacebelowfrontalmargin,separatedby segmentbroader than third, almost but not quite
narrow septum. Anterolateral margin granular, reaching to base of coxa of last pair of legs.
evenly arched, divided into 3 confluent broad Second segment much narrower than first or
lobes separated by two small but distinct third. Fourth tosixth segmentstapering. Telson
notches; firstlobelongerthan second, third lobe rounded triangular, slightly longer than broad at
notclearlyseparatedfromposterolateralmargin. base, longer than precedingsegments.
Posterolateral margins slightly convergent. Gonoporescoxal;penisliesexposedingroove
Posterior margin, very broad, only slightly less between sternites 7 and 8. G1 very slender,
than maximum carapacewidth; coslate; slightly sinuous; distal part weakly recurved, tip very
and evenly convex. Posterior margin of epis- slender,taperingtoasharppoint;aseriesofstout
tome, triangular medially with distinct median setaepresentsub-proximally (Fig. 4C). G2very
incision; medio-lateral incisions vestigial; short, sigmoid, tipvery long and slender, armed
lateral margins, straight, oblique. Endostomial with single long, fine seta terminally.
ridgespresent,confined tolowerhalfofefferent
Distribution
branchial canal.
Third maxillipeds occupying most of buccal Only known from the type specimen from
cavity. Merusquadrangular,c. 1.4timesbroader Lindeman Is., mid-eastern Queensland.
thanlong;outerdistalmarginproduced(Fig.4E)
(left third maxilliped of the holotype (Fig. 4F) Remarks
hasanapparently aberrant merus). Ischiumwith The merus of the left third maxilliped of the
lateral margins sub-parallel except near base holotype may be considered aberrant. Unlike
where width increases; c. 1.8 times longer than the right merus, that on the left has the outer
width medially; inner margin slightly convex, distal margin rounded and not produced at all.
granular over distal third, becoming smooth Theinnerproximal margin isalsomoreoblique-
proximally, armed with a row of stiff setae ly recedingthan thaton the right(Fig. 4F). Both
originatingbehindmargin. Exopodreachingex- these differences give the merus a more ovoid
ternal angle ofthe merus. shapeandthethirdmaxillipedamuch lessquad-
Ambulatorylegsfringedwith longsetae; third rateappearance (Fig. 4E, F). Theleftmaxilliped
pair longest; unarmed except for serrated coxal agrees with the right in all other aspects. It is
plate (Fig. 4G), which is produced to lie over probable that the shape of the left merus is a
proximal part of ischium. Dactyli relatively result of previous damage and aberrant
long, subequal in length to propodi; armed with regrowth. The form ofthe outerdistal margin of
longslenderterminalclaw; bearing5 thick rows the third maxilliped merus has been used exten-
oflongsetae,onealongdorsal mid-line, andtwo sivelyinrhizopinetaxonomy(Ng, 1987),andthe
pairs spaced evenly on anterior and posterior presentobservationsofasymmetrical thirdmax-
surfaces. Dactyli of first three pairs gently illiped meri in C. lindemanensis indicates that it
recurved; dactyli of fifth pair curved slightly may sometimes be less reliable than previously
believed;especiallywhenonlysinglespecimens
upwards.
Chelipeds stout, left slightly larger. Merus are known.
armed on posterior margin with blunt, granu-
ACKNOWLEDGEMENTS
lated, sub-distal tooth. Carpus with inner angle
granulate, bearing a broad fringe of long setae,
otherwise naked. Chela naked except forbroad Thisworkwasfunded, in part, by agrantfrom
524 MEMOIRS OFTHE QUEENSLAND MUSEUM
the Australian Biological Resource Study to of the genus Rhizopa Stimpson, 1858 and the
P.J.F.D., forworkon Australianxanthoidcrabs; statusofthe Rhizopinae Stimpson, 1858(Crus-
and a research grant (RP900360) to P.K.L.N. tacea: Decapoda: Brachyura). Indo-Malayan
from the National University of Singapore. Ms Zoology 4(1): 69-111, PI. 1.
Clare Bremner is thanked for her execution of 1989. The Indo-Pacific Pilumnidae IV. On Cryp-
Figure 4. tocoeloma haswelli Rathbun, 1923 (Crustacea
Decapoda, Brachyura).Crustaceana56: 47-57.
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1990. Indo-Pacific Pilumnidae VI. Luteocarcinus
sordidusnewgenusandspecies,frommangrove
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Davie and C.D. Woodroffe (eds),‘Coasts and of Heteropilumnus subinteger (Lanchester,
tidal wetlands of the Australian monsoon 1900) and Heteropilumnus hirsutior (Lan-
region,’ A. N. U.NorthAus.Res.Unit, Darwin,
chester, 1900) stat. nov., with description of a
GUINMOaTn,grDo.v1e96M9o.n.Rec1:he2r5c9h-e2s75p.reliminaires sur les new species, Heteropilumnusholthuisisp. nov.
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