NEW SPECIES OF PERICLIMENAEUS BORRADAILE (CRUSRACEA DECAPODA PONTONIIAE) FROM ASHMORE REEF, NORTH WESTERN AUSTRALIA, WITH REMARKS ON P. PACHYDENTATUS BRUCE, 1969

2005·6.1 MB·English

by  A J Bruce

RecordsoftheWesternAustralianMuseum22:325-342(2005).
New species of Periclimenaeus Borradaile (Crustacea: Decapoda:
Pontoniinae) from Ashmore Reef, North Western Australia,
with remarks on P. pachydentatus Bruce, 1969
AJ.Bruce
QueenslandMuseum,P.O.Box3300,SouthBrisbane,Queensland4101,Australia
e-mail:[email protected]
Abstract -Two new species of the pontoniine shrimp genus Periclimenaeus,
fromascidianhostsfromAshmoreReef,WesternAustralia,aredescribedand
illustrated. Periclimenaeus kottae sp. nov., an associate of Didemnum
membranaceum Sluiter, is one of the smallest pontoniine shrimps known.
Periclimenaeusmatheraesp.nov.isanassociateofHypodistomadeerata(Sluiter).
ComparativefiguresareprovidedofP.pachydentatusBruce,1969,therangeof
whichisextendedtothePhilippines.
INTRODUCTION (Berggren, 1997), followed by P. bidentatus Bruce,
The genus Periclimenaeus Borradaile, 1915, 1970, and P. pachydentatus Bruce, 1969, from
includesanumberofsmallpontoniineshrimpsthat Hibernia Reef (Bruce 1992) and more recently, P.
occur mainly in all tropical waters, particularly on minutus, from ChurchiU and Albert Reefs, Western
coralreefs, and live in associationwith avariety of Kimberley(Berggren1997).Periclimenaeusbidentatus
sponge and ascidian hosts, generally as andP. minutus arespongeassociates,theothers are
heterosexualpairslivingininternalcavitiesoftheir associatesofascidians.
hosts. They are characterised by the presence of Further information is also provided on P.
grossly unequal chelae on the second pereiopods, pachydentatus, with a record from the Philippines,
thelargerofwhichhasaconspicuousmolarprocess thefirstoccurrenceoutsideAustralianwaters.
on the dactylus, which opposes into a fossa on the CL refers to the post-orbital carapace length;
fixed finger, the combination forming an effective NTM,NorthernTerritoryMuseum,Darwin;WAM,
sound-producing mechanism remarkably Western Australian Museum, Perth; ZMUC,
convergentwiththatfoundinthepontoniinegenus ZoologyMuseum,UniversityofCopenhagen.
Coralliocaris Dana and some genera of the
Alpheidae.
SYSTEMATICS
Periclimenaeus is the second most speciose genus
in the subfamily Pontoniinae, after Periclimenes SubphylumCRUSTACEA
Costa, 1844. At present 48 species are known from
the Indo-West Pacific region where they are found OrderDECAPODALatreille,1802
mainly as associates ofmarine sponges, although a
number are also known from ascidian hosts. The FamilyPALAEMONIDAERafinesque,1815
hosts of several species are yet to be identified. SubfamilyPONTONIINAEKingsley,1878
FromAustralianwaters 19 specieshavesofarbeen
reported by Davie (2002) and P. minutus Holthuis, GenusPericlimenaeusBorradaile,1915
1952, reported by Berggren (1997), was not
PericlimenaeusBorradaile,1915:207.
included, making a total of 20 species. The
discovery of further species from ascidian hosts
collected atAshmore Reef,north westernAustralia Periclimenaeuskottaesp.nov.
nowraisestheAustralianPericlimenaeusfaunato22 Figures1-3
species,mostofwhichareassociatedwithsponges.
FourspeciesofthegenusPericlimenaeushavebeen Material Examined
previously reported from Western Australia. Australia,WesternAustralia: 1 ovig.$ holotype,
Periclimenaeus hecate was reported from Cape stn WAM 174.93, Ashmore Reef, outer s,lope, 6-16
WAM
Jaubertby Balss (1921, as ? Coralliocaris hecate, and m, coll. L. Marsh, 16 September 1986, C
later from Maret Island, Western Kimberley 34444.
326 A.J.Bruce
Diagnosis merus ventrally spinulate, minor second
Rostral dentition 3/0, without supraorbital pereiopod dactyl cutting edge coarsely dentate,
spines, first pereiopod chela distally subspatulate, ambulatory dactyls completely unarmed, with
major second pereiopod with chela smooth, rounded boss proximally, exopod of uropod
dactylar cutting edge distally finely denticulate. laterallyunarmed.
PontoniineshrimpsfromAshmoreReef 327
Description without accessory pigment spot, diameter about
Avery smallpontoniineshrimp ofsubcylindrical 0.25ofCL,stalkshort,robust.
bodyform. Mandible (Figure 2A). Rather weak, corpus
Rostrum (Figure IB). Short, about 0.45 of CL, to without palp: molar process (Figure 2B)
level of anteroverted comeal margin, not reaching subcylindrical, tapering slightly distally, obliquely
todistalmarginofproximalsegmentofantennular tnmcate, with two acute teeth posteriorly, margins
peduncle, slender, without distinct carinae, dorsal setose: incisorprocess (Figure2C) slender,tapering
margin with small proximal tooth at about 0.25 of distally,terminatingintwosmallacuteteeth.
rostrallength, with two larger acute teeth at about Maxillula. Lost in dissection. Lower lacinia short,
0.5 and 0.75, with sparse interdental setae, ventral stout,withfewlongrobustdistalspines.
marginunarmed. Maxilla (Figure 2D). Palp about 3.2 times longer
Carapace (Figure lA). Smooth, orbit feebly thanwide, withoutpreterminalplumose seta, with
developed, inferior orbital angle obsolete, sparse shortplumose setaeproximo-laterally;basal
supraorbital spines or tubercles and hepatic spines endite simple, distally expanded, with about 8
absent,antennalspineacute,marginal,anterolateral slender simple setae, coxal region convex,
margin of branchiostegite not produced, broadly scaphognathite normal, about 2.25 times longer
rounded. thanbroad.
Abdomen. Smooth, first segment without First maxilliped (Figure 2E). Palp subcylindrical,
anterodorsal lobe, pleura broadly rounded, sixth with preterminal seta medially, basal endite
segment about 0.4 of CL, 1.4 times longer than sparsely setose distally, glabrous proximally, coxal
deep, 1.2 times longer than fifth segment, enditenotdistinguishable,non-setose,carideanlobe
posterolateralangleblimt,posteroventralanglewell broad,sparselysetose,withabout12shortplumose
developed,acute. setae,flagellumslenderwithfourterminalplumose
Telson (Figure IH). About 0.85 of CL, 1.9 times setae;epipodsmall,deeplybilobed.
longer than anterior width, lateral margins Second maxilliped (Figure 2F). Of normal form,
sublinear,convergingstronglyposteriorly,withtwo dactylarsegmentabout2.5timeslongerthanbroad,
pairs ofsmall subequaldorsalspines, about0.08 of with numerous long coarsely serrulate spines,
telson length, at 0.24 and 0.62 of telson length, exopod slender with four plumose terminal setae,
posteriormargin(Figure11)rounded,withoutacute epipod small, simple, elongate, without
median point, about 0.35 of anterior width, with podobranch.
small lateral spines, slightly smaller than dorsal Thirdmaxilliped(Figure2G).Short,stout,reaching
spines, well developed intermediate spines, about to about half length of proximal segment of
0.25oftelsonlength,submedianspinessubequalto antennular peduncle, ischiomerus fully fused to
dorsalspinesinlength,moreslenderandsetulose. basis, combined segment about 3.3 times longer
Antennule (Figure 1C). Short, robust, proximal thanbroadcentrally,medialmarginsparselysetose,
segment about 1.5 times longer than basal width, basal region stronglyconvex,penultimate segment
with small ventromedial tooth, lateral border about 0.8 of combined segment length, 2.5 times
concave, without distinct distolateral tooth, longer than width, sparse slender spines medially,
styloceriteshort,broad,acute,reachingtoabout0.3 distal segment 2.5 times longer than proximal
of segment length; statocyst present; intermediate width, taperingdistallywithfew groupsofslender
and distal segments short and stout, combined spines;exopodnormal,withfourplumoseterminal
equal to about 0.5 of proximal segment length, setae; coxa without medial process, lateral plate
upper flagellum short, biramous, proximal three suboval,elongate,withoutarthrobranch.
segments stout, fused, shorter free ramus with Thoracic sternites. Narrow, without special
single short segment, longer ramus with four features.
subcylindrical segments, about seven groups of First pereiopod (Figure 2A). Short, robust,
aesthetascs; lower flagellum ofsimilarlength, with exceedingcarpoceriteby abouthalfpropod length;
sevensubcylindricalsegments. chela (Figure 2B) with compressedpalm, about 1.4
Antenna (Figure ID). Short, stout, coxal segment times longer than deep, fingers subequal to palm
with conspicuous medial tubercle, basicerite length, slightly subspatulate, sparsely setose,
laterallyunarmed,carpoceritesubcylindrical,about cutting edges sharp distally, entire, medially and
6.0 times longer than width, extending to level of laterally, tips bidentate: carpus short, stout, 2.5
distal margin of antennular peduncle, flagellum times longerthanwide, taperingproximally, about
short; scaphocerite (Figure IE) small, about 2.6 0.7 ofpalm length; merus subcylindrical, 3.4 times
times longer than distal width, not exceeding longer than width, 1.2 times carpal length, slightly
carpocerite,lateralmarginstraight,withsmallacute shorter than chela; proximal segments without
distolateral toothreaching to level of distalmargin specialfeatures.
oflamella. Major second pereiopod (Figure 2C). Well
Eye(FigureIF).Corneawellpigmented,globular. developed, chela about2.0 timesCL,palmsmooth,
328 AJ.Bruce
Figure2 Periclimenaeus kottae sp. nov., holotype, ovigerous female. A, mandible. B, same, molar process. C, same,
incisorprocess. D,maxillula.E,firstmaxilliped.F,secondmaxilliped.G,thirdmaxilliped.
glabrous, 1.7 times longer than deep, moderately straight, entire, tip acute, strongly hooked; carpus
compressed, tapering slightly distally, fingers about 0.38 of palm length, broadly expanded
(Figure 2D) about 0.37 of palm length, dactylus distally and tapered proximally, about as long as
about 1.5 times longer than deep, outer margin widedistally,unarmed;merus(Figure2F)about0.3
semicircular, cutting edge with large low molar ofpalmlength,1.5timeslongerthandeep,tapering
process proximally, anterior margin slightly slightly distally, with 4 small acute ventral
bilobed, distal cutting edge (Figure 2E) short, denticles; ischium slightly longer than merus,
concave, finely denticulate with blunt imbricate robust, tapering proximally, 2.0 times longer than
denticles, tip stout, acute, fixed finger with large central width, unarmed; basis and coxa robust,
deep fossa proximally, cutting edge distally withoutspecialfeatures.
PontoniineshrimpsfromAshmoreReef 329
Figure3 Periclimenaeuskottaesp.nov.,holotype,ovigerousfemale.A,firstpereiopod. B,same,chela.C,majorsecond
pereiopod. D, same, fingers. E,same,cuttingedgeofdactylus. F,same,merus. G,minorsecond pereiopod.
H,same,fingers.1,thirdpereiopod.J,same,propodanddactyl.K,same,dactyl.L,fourthpereiopod,propod
anddactyl.
330 AJ.Bruce
Minor second pereiopod (Figure 3G). Smaller than SystematicPosition
major pereiopod; chela about 0.8 of major chela Periclimenaeus kottae sp. nov. is most closely
palm length, 1.2 ofCL, palm 2.0 times longer than related to P. hecate (Nobili, 1904) and P. crassipes
deep, subuniform, slightly compressed, smooth, (Caiman, 1939). It may be distinguished from the
glabrous, fingers (Figure 3FI) about 0.27 of palm formerspeciesbyitsmuchsmallersize,CL0.9mm,
length, dactylus over-reaching fixed finger, about androstraldentition3/0asopposedto3.5mmand
2.0 times longer than central depth, outer margin 4-5/0,inP. hecate. Also,rostrummore slender,not
strongly convex, cutting edge sinuous with about reaching distal margin of proximal segment of
12coarse,bluntteethofincreasing size distally, tip antennular peduncle vs distinctly exceeding distal
bluntlyhooked;fixed finger about 1.2 times longer margin of proximal segment; first pereiopod with
than proximal depth, cutting edge not grooved, carpus and merus shorter than chela ns much
concave, entire, with small acute tooth proximally, longer; major second pereiopod with distal cutting
tip curved,acute;carpusabout0.38ofpalmlength, edge of dactylus minutely denticulate, merus
1.2 times longer than distal width, tapered ventrally spinulate, vs entire and non-spinulate;
proximally, expanded distally, unarmed; merus minor second pereiopod chela with palm twice as
about 0.6 of palm length, 2.5 times longer than long as deep, with dactylar cutting edge sinuous
greatest depth, tapering slightly proximally, with about 12 coarse teeth vs three times, and
widroutventraldenticulations;ischiumabout0.8of straight with about 40 finely acute teeth;
meral length, 2.8 times longer than distal width, ambulatory dactyl with corpus twice as long as
tapering proximally, unarmed; basis and coxa basal width, with pronounced rounded ventral
withoutspecialfeatures. swelling proximally vs subcircular, without
Third pereiopod (Figure 31). Short, robust, proximal ventral swelling. From P. crassipes, P.
exceeding antennular peduncle by chela length, kottae may again be distinguished by its much
dactyl (Figure IG) about 0.27 of propod length, smaller size, total length 4.7 mm and rostral
corpus (Figure 3K) compressed, twice as long as dentition 3/0, vs 10.5 mm and 4/0. Periclimenaeus
central depth, tapering distally, distal width about crassipes has only been illustrated with a whole
0.5ofproximalwidth,dorsalmarginfeeblyconvex, animalfigure, and the dactyl ofthe fifthpereiopod
ventral margin without distal accessory tooth, provided by Caiman (1939) and the third
distally almost straight, proximally with large pereiopod, figured by Bruce (1974). The latter
rounded boss, with pair of distolateral sensory shows the "massive and flattened" appendage
setae,unguisstout,simple,curved,about1.75times described by Caiman, with the propod 2.7 times
longer than basal width, 0.33 of corpus length; longer than proximal width and tapering very
propod (Figure3J) about0.3 ofCL, stout, 2.5 times strongly distally, where its width is about 0.25 of
longerthanmaximaldepth atabout0.33 oflength, the proximal width, quite unlike P. kottae. The
with stout similar distomedial, distoventral and carpusisevenmoreinflated,lengthabout0.9ofthe
distolateral spines, about 0.12 of propod length; propod length, and almost twice as long as wide.
carpus stout, 1.5 times broader than propod, 2.4 The dactyl is, as remarked by Caiman, without a
times longer than wide, unarmed;merus 1.5 times basalprotuberance,unlikeP. kottae.
propod length, 2.5 times longer than width,
unarmed; ischium subequal to carpus length, 2.5 Colouration
timeslongerthandistalwidth,taperingproximally, Nodata.
unarmed; basis and coxa robust, without special
features. Fourthpereiopod similar. Fifthpereiopod
Host
dactyl without ventral boss, 0.5 of propod length,
propod2.8timeslongerthandeep. Didemnum membranaceumSluiter, 1909. Thehostis
2.6Urtoipmoeds(lFoingguerretIhJ)a.nPbrrootaodp,odliatteerualnamramregdi;nemxaoipnoldy waesctoemrmnonPalciyfico,cciunrrAiunsgtrsapleicaiedsowfrnomtotHheouttrmoapinc'asl
straight,unarmed,withwelldevelopedacutedistal Abrolhos on the west coast and Caloundra on the
tooth (Figure IK), with mobile spine medially, east;andithasalsobeenrecordedfromHongKong.
reachingalmosttolevelofdistalmarginoflamella;
endopod subequal to exopod length, 2.6 times Etymology
longerthanwide. Thespeciesis dedicated toDrPatriciaKott,A.O.,
Ova.Few,about10,ofnormalsize. inrecognitionofhercontributiontothestudyofthe
Ascidiacea.
Measurements(mm)
Post-orbital carapace length, 0.9; carapace and Remarks
rostrum, 1.4;totalbodylength (approx.),4.7;major Periclimenaeus kottae must be one of the smallest
second pereiopod chela, 1.85; minor second pontoniine shrimps recorded, with an adult total
pereiopodchela,1.15;lengthofovum,0.4. lengthofonly4.7mm.
0
PontoniineshrimpsfromAshmoreReef 331
ThevastmajorityofPericlinienaeiisspecieshave a Dactylofmiriorsecondpereiopodwithcutting
biunguiculatedactylontheambulatorypereiopods, edgedentate 3
often with additional ornamentation. In the Indo
West-Pacific region, only four species are known 3. Dactylofminorsecondpereiopodwithcutting
edge with numerous small teeth, about 40,
thatlackbiunguiculatedactylsontheseappendages
alongwholecuttingedge;R.4-5/0
Mostofthesearerare andtwoare knownfromthe
P.hecate(Nobili)
type material only. These species do not appear to
be closely related or to constitute a distinct group Dactylofminorsecondpereiopodwithcutting
and the loss of the distal accessory tooth on the edgewithfewlargeteeth(about10-12) 4
ambulatory dactyl has possibly occurred 4. Large species, dactyl of minor second
independently in several different evolutionary pereiopod much longer than fixed finger,
lines. withabout10bluntteethdistally;carpusand
PericlimenaeiisarthrodactyhisHolthuis,1952,isstill propod of third pereiopod greatly swollen,
known only from the holotype specimen collected propod 3 times broader proximally than
from Pulau Sailus ketjil, Kepulauan Tenga, distally;dactyluswithoutbasalprocess;R.4/
m
Indonesia, in 1899, from 18 or less, from an P.crassipes(Caiman)
unknown host. Periclimenaeus hecate (Nobili, 1904) Small species, dactyl of minor second
swuabssefqirusetnrtelpyorrteedporftreodm fDjriobmoutKienaynad,hCaosmboereon pereiopod slightly longer than fixed finger,
withabout12bluntteethdistally;carpusand
Islands, Seychelle Islands, Reunion, Maidive propod of third pereiopod not greatly
Islands, Indonesia, China andWesternAustraliain swollen, propod less than twice broader
Diplosoma niolle (Herdman, 1886). Periclimenaeus proximally than distally; dactylus with
crassipeshasbeenreportedfromoffOmanandfrom roundedbasalprocess;R.3/0
DarwinHarbour,NorthernTerritory,inassociation
P.kottaesp.nov.
with the ascidian Didemnum psammatoides.
Periclimenaeus sernda Bruce and Coombes, 1995, is
known only from the type material from Orontes
Reef, Port Essington, Northern Territory, from 12 Periclimenaeusmatheraesp.nov.
m., from Leptoclinides incertus Sluiter. It may be Figures4-8
noted that these species are fotmd in association
MaterialExamined
withthreedifferentascidianhostgenera.
It may also be noted that the mouthparts of P. AsAhumstorraeliRae,efW,eWsetsetrnLaAguosotnraelnitar:an1ce.S,12h°o01l3o.t2y6p'e,S
kottae closely resemble those of P. robustus.
122°059.28' E, 4-7 m, coll. K. Gowlett-Hohnes, 1
Borradaile, 1915, as illustrated in Borradaile (1917, NTM
October2002,AJB#3225, Cr013631.
plate55figures20f-i), the typespeciesofthegenus
Periclimenaeus. The mcmdible and maxillula of P.
Diagnosis
robustuswerenotillustrated.
These species donot appear tobe closelyrelated Rostrum well developed, slender, dentition 7/0;
or to constitute a distinct group andthe loss ofthe supraorbitaltuberclespresent;inferiororbitalangle
distalaccessorytoothonthe ambulatorydactylhas produced; antennal spine large; first abdominal
probably occurred independently in several segment without anterodorsal lobe;first pereiopod
slender, chela fingers subspatulate, cutting edges
differentevolutionarylines.
These speciesmaybe conveniently distinguished entire;majorsecondpereiopodmassive,dactylwith
fromP.kottaebythefollowingkey. large molar process, cutting edge distally entire,
palm finely asperulate, merus ventrally entire;
minorsecondpereiopoddactylelongate,exceeding
KeytoIndo-WestPacificPericlimenaeusspecies fixed finger, cutting edge concave, finely
withambulatorydactylslacking
denticulate, fixed finger grooved, inner cutting
adistalaccessorytooth
minutely denticulate; third pereiopod dactylus
1. Supraorbital spines present, third pereiopod biunguiculate,ventralborderminutelydenticulate,
dactyl large and slender, with articulated
without acute basal process, propod with 3 distal
unguis, with minute ventral denticulations;
spines, 5 ventral spines; uropodal exopod laterally
R.5/0 P.arthrodactyhisHolthuis unarmed;telsonwithlargedorsalspines at0.2and
- Supraorbital spiires absent, third ambulatory 0.6oftelsonlength.
dactylwithsimple,non-articulatedtip 2
2. Dactylofminorsecondpereiopodwithcutting Description
edge entire, of major second pereiopod A medium sized species of Periclimenaeus, of
minutelydenticulate;R4/0 subcylindricalbodyform.
P.serndaBruceandCoombes Rostrum (Figure 4B). Slender, compressed, acute.
332 A.J.Bruce
Figure4 Periclimenaeus matherae sp. nov., holotype male. A, carapace and rostrum. B, same, rostrum and orbital
region.C,sixthabdominalsegment,dorsal.D,antennule.E,same,proximalsegment,dorsal.F,same,lateral.
G, antenna. H,same,scaphocerite. I,eye, dorsal.J, third pereiopod, distalpropodand dactyl. K,telson.
L,same,posteriorspines.M,uropod.
PontoniineshrimpsfromAshmoreReef
333
reaching to about to middle of distal segment of about 2.2 times longer than distal width, not
antennular peduncle, about 0.5 of CL, dorsal exceedingcarpocerite, lateral margin straight, with
margin sublinear, with 7 acute teeth, first tooth welldevelopedacutedistolateraltoothatabout0.68
situated over posterior orbital margin, slightly oflamellarlength.
transversely broadened, distal tooth small, Eye (Figure 41). Cornea hemispherical, well
intervening teeth long, slender, acute, with short pigmented, diameter about 0.16 of CL, without
plumose setae on dorsal edges, teeth longer than accessory pigment spot; stalk subcylindrical, 1.2
rostral depth, ventral border mainly straight, times corneal diameter proximally, tapering
slightlyup-curveddistally,unarmed,non-setose. distally,about1.2timeslongerthanbasalwidth.
Carapace (Figure 4A). Smooth, glabrous, with Mandible (Figure 5A). Corpus normal, without
small subacute supraorbital tubercles, antennal palp; molar process (Figure 8A,B) subcylindrical,
spinelargerobust,inferiororbitalangle(Figure7A) taperingslightly,transverselyobliquedistally,with
produced as small blunt process, hepatic spine single acute ventral tooth, margins fringed with
absent, anterolateral branchiostegite not produced, denselongslendersetae;incisorprocess(Figure8C)
broadlyrounded. slender, curved, transversely truncate distally with
Abdomen. Smooth,glabrous;firstsegmentwithout fivesmallsubequalacuteteeth.
anterodorsal lobe, pleura broadly rounded, sixth Maxillula (Figure 5B). Palp (Figure 8D) slender,
segment (Figure 4C) about 0.3 of CL, 2.8 times feebly bilobed distally, lower lobe with small
longer than deep, 1.2 times longer than fifth tubercle bearing single short simple seta; upper
segment, posterolateral angle blunt, posteroventral lacinia (Figure 8E) short, broad, distal margin
anglewelldeveloped,acute. transversely truncate, with 11 slender acute simple
Telson(Figure4K).About0.6ofCL;dorsalsurface teeth, fully fused to lacinia, with sparse simple
sparsely setose; 2.0 times longer than anterior setae; lower lacinia short, blunt, with numerous
width, lateral margins feebly concave, posteriorly distalsetae.
convergent, with 2 pairs of submarginal dorsal Maxilla (Figure 5C). Palp elongate, slender, non-
spines (Figure 8G), at about 0.2 and 0.6 of telson setose; basal endite bilobed, upper lobe short,
length, spines about0.15 oftelson length, posterior broader than lower, with 9 simple setae distally;
spinesslightlymoreslenderthananterior,posterior lower lobe damaged; coxal endite obsolete, medial
margin (Figure 4L) about 0.4 of anterior margin margin convex, non-setose; scaphognathite well
width, lateral spines small, acute, about 0.75 of developed, 2.5 times longer than broad, anterior
dorsal spine length, intermediate spines robust, lobebroad,1.2timeslongerthanwide.
about 5.5 times longer than basal width, 0.25 of Firstmaxilliped (Figure5D). Ofnormalform;palp
telson length, 1.8 times lateral spine length, slender, elongate, flattened, extendingwellbeyond
submedianspines0.75ofintermediatespinelength, distal margin of basal endite, with single short
setulose. simple seta at 0.66 of medial margin length; basal
Antennule (Figure 4D). Short, robust, proximal enditebasalenditesparselysetosedistally,glabrous
segment (Figure 4E) with medial length about 1.6 proximally, coxal endite not distinguishable,
times longer than basal width, with large slender sparsely setose, exopod with caridean lobe broad,
acute ventromedial tooth (Figure 4F, 8F inset), 2.5timeslongerthanwide,withnumerousplumose
lateral border angular, distally concave, with well marginal setae; flagellum slender, with 7 plumose
developed distolateral lobe (Figure 8F) with acute terminal setae; epipod small, deeplybilobed, distal
distolateraltooth,styloceriteshort,broad,subacute, lobelargerthanproximal.
reachingtoabout0.4ofsegmentlength,distolateral Second maxilliped (Figure 5E). Of normal form;
margin setose; statocystpresent, granular statolith; dactylar segment narrow, 4.0 times longer than
intermediate and distal segments short and stout, wide, with numerous finely serrulate spines
combined equal to about 0.6 of proximal segment medially; propodal segment well developed,
length,upperflagellumshort,biramous,proximal7 distomedial border convex, with numerous finely
segments stout, fused, shorter free ramus with serrulate spines; carpus, ischiomerus and basis
single short segment, longer ramus with 4 without special features; exopod with well
subcylindrical segments, about 16 groups of developed flagellum, with 7 plumose distal setae;
aesthetascs medially, with short simple spiniform coxaangularlyproducedmedially,withfewsimple
setae laterally; lower flagellum of similar length, setae,epipodsmall,suboval,withoutpodobranch.
withabout20subcylindricalsegments. Third maxilliped (Figure 5F). Of normal form,
Antenna (Figure 4G). Short, stout; coxal segment reaching to about distal end of carpocerite;
with conspicuous medial tubercle, basicerite endopod with ischiomerus semi-fused to basis,
laterallyunarmed,carpoceritesubcylindrical,about combined segment about 4.4 times longer than
4.0 times longer than distal width, extending to central width, medialborder sparselysetose, with
slightly beyond distal margin of scaphocerite, simple setae, coxal border convex, penultimate
flagellum short; scaphocerite (Figure 4H) small. segment subcylindrical, about 4.0 times longer
334 A.J.Bruce
Figure5 Periclimenaensmatheraesp. nov.,holotypemale. A,mandible. B, maxillula. C, maxilla. D, firstmaxilliped. E,
secondmaxilliped.F,thirdmaxilliped.Scalebar0.5mm.