Memoirsofthe MuseumofVictoria 57(I): 39 56 (1998) A REVIEW OF NEBALIELLA (CRUSTACEA: LEPTOSTRACA) WITH THE DESCRIPTION OF A NEW SPECIES FROM THE CONTINENTAL SLOPE OF SOUTHEASTERN AUSTRALIA Gf.nefor K. Walker-Smith Crustacea, Museum ofVictoria, 71 Victoria Crescent, Abbotsford, Victoria 3067, Australia and DepartmentofZoology, The UniversityofMelbourne, Parkville. Victoria 3052, Australia ([email protected]) Abstract Walker-Smith, G.K., 1998. A review of Nebaliella (Crustacea: Leptostraca) with the description ofanew species fromthe continental slope ofsoutheastern Australia. Memoirsof the Museum ofVictoria 57: 39-56. The genus Nebaliella Thiele, 1904 is reviewed and a new species is described from Point Hicks, Victoria, Australia. This is the first record ofthe genus from Australia and the fifth species ofNebaliella. Previously only 47 individuals world-wide had been recorded making the addition of9 individuals to the literature significant. Sexual dimorphism within the genus is discussed and a key to the species is included. Introduction the Weddell Sea (5 specimens) and Kerguelen (I specimen). Nebaliella antaretiea has been Nebaliella Thiele, 1904 belongs to the leptostra- recorded in shallow water ranging in depth from canfamilyNebaliidae Baird, 1850with five other 9 m to 190 m while depth records forN. extrema genera; Nebalia Leach, 1814, Paranebalia Claus, range from 160 to 385 m. 1880, Dahlella Hessler, 1984, Sarsinebalia Dahl, In 1932 Clark described Nebaliella eaboti from 1985 and Speonebalia Bowman, Yager and a single male found in the Cabot Strait between Uiffe, 1985. The main features distinguishing NewfoundlandandCape Brenton Island, Canada, Nebaliella from other nebaliids are: the presence at a depth of 378 m. Nebaliella eaboti has also oflarge curved eyestalks lacking visual elements been recorded in New Jersey, USA on the lower m and denticles, a rostral keel extending beyondthe portion of the continental slope at 2085 rostral flange, thoracopods without epipods and (Hessler and Sanders, 1965) andmthe Rockall pleopod 6 largerthan pleopod 5. Trough at depths of 1390-2900 (Mauchline Nebaliella was erected for its type species and Gage, 1983). Nebaliella breviearinata. Nebaliella anlarctiea from Kerguelen, Southern the fourth species reported, was described from Ocean (Thiele, 1904). Thiele (1904) suggested a a single female from 270 m off the Princess specimen collected from Akaroa Harbour, New Ragnhild Coast. Antarctica (Kikuchi and Gamo, Zealand also belonged to this species. A year 1992). later Thiele (1905) described a second species, The fifth species, described here, was collected N. extrema from 15 specimens collected off offthe southeastern coast ofVictoria, the eastern the coast of Kaiser Wilhelm II Land, Eastern coast of New South Wales and Tasmania, Antarctica. Nebaliella extrema has also been Australia. The species was the only one in its recorded from Western Antarctica in the Palmer genus collected during extensive sampling on the Archipelago (Cannon, 1931). In a series of continental slope in this region (Poorc ct al., expeditions in 1972, 1974-75 and 1982 to the 1994). Several other undescribed species of subantarctic region of Kerguelen and Crozet Nebaliidae were collected at the same time. N. Island, Ledoyer(1993) recordedten specimens of deelivatas sp. nov. is a deep water species, found N. antaretiea from Kerguelen. These specimens on the continental slope in waterat 996-1840 m. included males and juveniles but females were The addition of an Australian species to not mentioned. During the same expeditions the literature extends the known geographical Ledoyer (1993) also recorded N. extrema from distribution ofthe genus (Table 1). 39 ' 40 G. K. WALKER-SMITH O—n°JO """ On Ia-j U03)'_g- "Oo3"n-o^'—3 Oh^n ^g^i-ToO'/—0-n)> ?S2rOo<<nn-U>2or00^n~n) "O<-N^ -i0at3 7,03g3 I-Sa7S3 awc<3>u.-wtc3>auiw"oc3>o, OJ _e .c jo u .c C/3 C/3 C/3 -a -a mi/-> On m On £ P o OI or^i r•r~—-- mro-o °oo ""o^n ^imr oto g3, o"j° — i CnI CnI 033 -a o 2 X3 CT3 03 fi s-l c « P B 03 Uh SOe3o0<r3Un NN3O?<e3Uw SOoe3O0r3n SeOU3O0r3nt-ILaEI3ni 2<ooao3a."ag0033 SoOu_O0<thD3e Ca_nai <U^ey,gTI0Chr33,ihtO0ilo3d .<">tvN303oh32r3i<s0«333-J<hsj«^-2Jr- 03" £> Harb Wilhe <CHJ aCOOJ Strait,Jers Trou Ragi 0O3 Hicks,NSW Tourvil Kerguelen, Kerguelen,Kerguelen, Antarctica E? Kerguelen, New o o Akaroa Kaiser O0h3 ">>. Cabot Off Rockall Princess <C03 Point Nowra,Cape (N ON ON % <d £ a03 o ON oin ON 3 eOnn 2 >o 3 a - a 53 H33 ^u0<s-3j ,aCs <C3oS3Il S 33 43 S333 -3O3 '^kS> u3U oo ^ S: ^ 5> . 1 RFVIFW OF NEBALIELLA (CRUSTACEA: LEPTOSTRACA) 41 All specimens examined came from the Composition. N. antarcticaThiele, 1904; N. bre- collections of the Museum of Victoria (NMV). vicarinala Kikuchi and Gamo, 1992; N. caboti Specimens were dissected and mounted in Clark, 1932; N. declivatas sp. nov.; N. extreme glycerol and slides were viewed under an Thiele, 1905. See Table 1 for distribution. OmwPilelcryuremmoopssducerospasewBe.nHta-eWw2hiatrooherlenatnuhmesOeplreayciodimumpseoutnossnaBmaXacn5nad0myebcrboaooddmyypluopcpua.aidrnlatds.s Re^b'lmemae^rndthso;^{T-tShhac^rsia^nrechtaalsltmikasxoafn,dNvNQhccfaUhlri(avhcelcd,ul)uur,oa,asanstcdrkiuncmvxsitsoc,uiimauke]ic but in most cases they have been figured without ta|ks ofDahk,lkl cakhlriensis but, unlike their setules so as not to obscure other details. ft cakhiriensis thc Cyestalks lack denticles. Ar22;;bosbMtrTDre1uv,-miT;am8taE,in,odneitysbhelosuerts;aaelcdkMospiX;nodAfIs,iIgm,ua1rax-eni8stl;elanranePa11a;-s1MP;f6XAol22lopwlamsena:otxpeiRonlOdnl,saa NA§anerlbsca:na„ne,aB8a8f2?u'sca(drNSteipjcbenloaens|oeitobh1pacs|lia.ldnagadcc)n4crabanaurdte()fanroLeNtccphftfauoulsssieteodrdpascioiasrn. 1-6; CR, caudal rami orfurca; A, anal scales. Thoracopodal epipods are absent in Nebaliella but present in other leptostracan genera. Pleopod Nebaliella Thiele 6 is larger tha^n p^leopo^d 5lin ^Neb^alie^lla «i jJfcWHW") NehaUella Thiele, 1904: 4 9, 24-25, Cannon, iIVmjit.. liiiab iolTlt. theS,erxeuvaerl.s.de.iimsotrrpuhe,i.sinm.ottTh-ihereNmeobsatl,ioibiuvaic•.ous sexualIlIy Type species. Nebaliella antarctica Thiele, 1904 dimorphic feature of males is the presence of a by monotypy and original designation. heavily setose peduncle and flagellum on antenna Diagnosis. Eyestalks strongly curved, extending '2 w^hich extendstothecaudal furea (Hgsoand 7). beyond the ventral margin ofthe rostral keel and ^gellum is twice as long as ,n emales. e rpleaoaaptsclietkpprrioaaanldlrgst.aifvcnliladseSnugm3adeiol.wsotietatMllhhaenmmaedasnciretobgtsnuia.tnleisaRn.roousonTtiuhrnsacollirrastaookecrweroaelolpwfioltdsmohesantrga3wgeeiirattnelhteoohtaunohntg,f nmeHflaaeollmgtueaeamsll,,relsyuehxmaoftsfloeafnNagd.leaislnnoaltgnuetmbnb,aenereamcyntoiInaocdd.absdsthaaeh.lnresodvocneadNmu.oudoacdnlhehecf.luun,orovtnaraeg,menn,an,Ala.,nIu1atdghoe-- pleopod 2 exopod not in pairs. Pleopod 6 longer amppears as a setose smgle article and is not found niales than pleopod 5. - Key to species ofNebaliella 1 Ratio ofrostral flangeto exposed keel approximately 1:1 (Fig. IE, F) 2 Ratio ofrostral flange to exposed keel approximately 3:1 (Fig. IA, 13) N. antarcticaThiele, 1904. 2. Carapace posterior margin not extending beyond pleonite 4 or less; body length more than twice carapace length; antenna 2 (Fig. 1G), article with short spine on dorsodistal edge, article 2 with slender seta on d1istoventral comerofarticle 2; mandibular palp with strong spine on article 2 (Fig. 1H) N. brevicarinata Kikuchi andGamo, 1992 Carapace posterior margin extending beyond pleonite 4; body length less than twice carapace length; antenna 2 without slender seta on distoventral cornerofarticle 2; mandibularpalpwithout strongspine onarticle2 3 3 Carapace posterior margin extending to pleonite 5; maxilla 2 endopod (female) 1-articulate; pleopod I (male, female PI unknown) exopod with a row of 13 setae increasing in length distally and becoming spiniform, along lateral margin N. cabotiClark 1932 Carapace posterior margin extending to pleonite 5; maxilla 2 endopod (female) 2-articulate in female (Fig. IL); pleopod I (female) exopod with 17-19 short setaeand8-10 longersetaealong lateral margin (Fig. 1M) N. c.xtrcma Thick, 1908 Carapace posterior margin extending beyond pleonite 7; maxilla 2 endopod l-articulate in female; pleopod 1 (female)exopod with 6short plumose setae and longer plumose setae along lateral margin (Fig. 4) 1 1 N. declivatassp. nov. — 42 G. K. WALKER-SMITH Nebaliella antarctka Thiele longer setae along lateral margin. Pleopod 6 Nebaliella antarctka Thiele, 1904: 4-9. 24-25. approximately 0.75 length ofpleonite 6. 1laic. 1937: 55 56.—Ledoyer, 1993: 77-78. Distribution. Princess Ragnhild Coast, Antarc- Diagnosis. Body more than twice length of tica: 270 m depth. carapace. Carapace posterior margin covering Remarks. Nebaliella brevkarinata was described pleonite 4 or less; without carina on anterolateral by Kikuchi and Gamo (1992) on the basis ofa lower corner. Ratio of rostral flange to exposed single female. The main character the authors keel approximately 3:1 (Fig. 1A, B). Antenna used to distinguish N. brevkarinata from other 2 with dorsal spine on article 1 and ventral species is a short vertical carina on the lower horn-like projection or heel on article 2 (Fig. cornerofthe anterolateral portion ofthe carapace 1C); without slender seta on distoventral corner (Kikuchi and Gamo, 1992). Ledoyer (1993) of article 2. Mandibular palp, article 2 with observed a similar carina on the carapace of a 4 setae; without strong spine onarticle 2. Maxilla specimen ofN. extrema, but believed they were 2 endopod (female) 1-articulate. T8 endopod still two distinct species as the armature of 4w-iatrhti1c9ul-a2t3esh(oFritg.setaIeD)a.ndP9Ilonegxeorpsoedtae((fienmcallued)- pdilfefoerpeondt.1Oanndthtehelpateedrualncmlaerogfinthoefanthteenpnlaewoeproed pilnegontietremi6.nal ones). Pleopod 6 half length of 91 elxonogpeordsNe.taberebvuitcaNr.ineaxitarheamsa8hasshor1t7-s1et9aeshaonrdt Distribution. Kerguelen, SouthernOcean; Akaroa setae and 8-10 longer setae. Antenna 2 peduncle Harbour, NewZealand. 9-190 m depth. article 1 has a short stout spine on the dorsodistal edge (Fig. 1G). A spine similar to this was Remarks. The most distinguishing feature recorded by Hale (1937) for N. antarctka of Nebaliella antarctka is its large rostral (Fig. 1C). Antenna 2 peduncle article 2 of N. flange. The ratio of the flange to exposed brevkarinata differs from all other species of keel is approximately 3:1 for N. antarctka Nebaliella having a long slender seta at the but only 1:1 for all other species of Nebaliella. laterodistal corner. The possession of a strong Nsepbecaileiselloaf Naenbatlairecltlkaa toispossaelssso 4thseetaeonoliyl cshpairnaectoenr uanrtiiqculee t2oNo.fbtrheevkmaarnidniabtual.ar palp is a article 2 of the mandibular palp. The number of articles in the protopod of maxilla 1 is Nebaliella cabotiClark uncertain. Thiele (1904) illustrated it as 1- articulate but Ledoyer (1993) drew a 3-articulate Nebaliella caboti Clark, 1932: 218-225.—Hessler structure. As in N. brevkarinata the carapace and Sanders, 1965: 72-73.—Mauchline and Gage, of N. antarctka extends only as far as pleonite 1983:628-630. 4, but unlike N. brevkarinata the carapace does Diagnosis. Body 1.75 x lengthofcarapace. Cara- not possess a carina on the anterolateral lower pace posteriormargin partially covering pleonite corner. 5; without carina on anterolateral lower corner. Ratio ofrostral flange to exposed keel approxi- Nebaliella brevkarinata Kikuchi and Gamo mately 1:1. Antenna 2 without dorsal spine Nebaliella brevicarinaia Kikuchi and Gamo 1992' on article 1; without slender seta or horn-like 83-89. projection on distoventral corner of article 2. Mandibular palp, article 2 with 2 setae; without Diagnosis. Body more than twice length of strong spine on article 2. Maxilla 2 endopod carapace. Carapace posterior margin covering (female) 1-articulate. Thoracopod 8 endopod 4- lploewoenritceor4neorr(Fliegs.s;Uw)i.thRactairoinoafroonstraanltefrloalnagteeratlo afretmiaculleatuen.kPnloewonp)odwit1heaxroopowdof(m1a3les,etapeleionpcroedas-1 exposed keel approximately 1:1 (Fig. IE, F). ing in length distally, becoming spiniform. Pleo- (RFoisgtrIuEm).wiAtnhtpernonxaimo2vewnittrhaoluttubdeorrcsuallatesppirnoeceosns pod 6 equal to or slightly longerthan pleonite 6. article 1; with slender seta on distoventral comer Distribution. Cabot Strait, eastern coast of of article 2 (Fig 1G). Mandibular palp, article Canada; offNew Jersey, USA; Rockall Trough 2 with I seta; with strong spine on article 2 Ireland; 378-2085 m depth. (Fig. 1H). Maxilla 1, protopodofpalp4-articulate Remarks. Clark (1932) described Nebaliella (Fig. II). Maxilla 2endopod(female) 2-articulate. caboti from a single male and Mauchline and TPlheoorpaocdopo1d e8xoepnoddopo(dfem1a-laer)ticu8latsehor(tFig.andIK).9 Gfraogme R(o1c9k8a3l)lprTorvoiudgehd,sIormeleanddr.awNiebnaglsieolflaafceambaoltei REVIEW OF XEBALIELLA (CRUSTACEA: LEPTOSTRACAl Figure 1. Nebaliella antarctica Thiele. A. B. rostrum, ventral and dorsal view; C. antenna 2; D. thoracopod 8. Nebaliella brevicarinata Kikuchi and Game. E. F, rostrum, ventral and dorsal view; G, antenna 2; H. mandible and mandibularpalp; 1. maxilla 1: J. carapace: k. thoracopod 8. Nebaliella extrema Thiele. L, maxilla 2; M. pleopod 1. Figurestraced fromthe following references: A C, Hale. 1937; D. Ledoyer. 1993; E K.. Kikuchi and M Gamo, 1992; L. Ledoyer, 1993. 44 G. K. WALKER-SMITH ismost similarto N. antarcticaandN. declivatas, A', extrema and N. brevicarinata is the lack of having a carapace without a carina, maxilla 2 a slender seta on the distoventral corner endopod I-articulate and thoracopod 8 endopod ofantenna 2 article 2 and the absence ofa strong with more than I article. Nebuliellacubotidiffers spine on article 2 of the mandibular palp, both fromN. antarctica in thesizeofthe rostral flange features possessed byN. brevicarinata. and carapace and the possession of 2 setae on article 2 ofthe mandibularpalp, N. antarctica has Nebalielladeclivatas sp. nov. 4. Nebaliella cuboti has a much larger pleopod 6 than either N. antarctica or N. declivatas, being Figures 2-1 equal to, or slightly longer than pleonite 6. Material examined. Ilolotype. Victoria. 76 km S of Nebaliella caboti also differs from N. declivatas Point Hicks (38°29.33'S, 149°I9.98'E), 1840 m, sandy having arelativelysmallercarapace, extendingto mud, fineshell, WlIOI epibenlhicsled,G.C.B.Poorect pleonite 5 and not 7 as in N. declivatas. aNl.MoVn ORV Franklin, 26 Oct 1988 (stn SLOPE 69), .134659 (female). Nebaliella extrema Thiele .13P4a6r6a4t,yp(ems.aleV,ictaolrlioat.ypCeo)l,leNctMedVwiJt3h45h9ol2oty(3p)e,. NNMMVV J34593(l). 193Nc1b:ci2l1i6ell2u2e1x.t—rLeemdaoyTehri,ele1,9931:90758: 6719.66 -Cannon I5N1°e5w.(SKoEu)t,h9W9a6lems,.m5u4dk,mfiEnSeEsaonfdN,ofwinreas(h3el4l°,52W.7H2O'S!, Diagnosis. Body less than twice length of epibenthic sled, G.C.B. Poore et al. on ORVFranklin, ccaorvaepraicneg. plCeaornaiptaece5; psoosmteertiiomresmawrigtihncaprairntaialolny 22TOacstma1n9i8a8.(st4n8SLkOmPE5E3)N,ENMoVf J3C4a5p9e4(1To).urville aptonrtoeexxriopmlooastveeerdnatlkrealellowatepurpbrceororcxnuielmraa.ttceRlapytrioo1c:e1os.fsR.roossAttrnartluemnflnwaaintgh2e o8P(14fo)2os,°ra0eNn0d.eM2yt5Vam'lS.uJ,od3n41a54Og98gR5°r4(eV32g.)a5Ft.5re'a,En)kW,lHin1O,2I6340epmOi,cbtegnr1ta9hvi8ec8ls(lwseiidnt,hSGLl.uCO.mPBpE.s withoutdorsal spinearticle 1; withoutslenderseta or horn-like projection on distoventral corner of Diagnosis. Body approximately 1.5 x length of article 2. Mandibularpalp without strongspineon carapace. Carapace posterior margin extending article 2. Maxilla 2 endopod(female) 2-articuIate beyond pleonite 7; withoutcarinaonanterolateral (Fig. 1L). Pleopod I exopod (female) with lower comer. Ratio ofrostral flange to exposed 17-19shortsetaeand 810 longersetaealonglat- keel approximately 1:1. Rostrum without proxi- eral margin (Fig. IM). Pleopod 6 as long as moventral tuberculateprocess. Antenna2 without pleonite 6. dorsal spine on article 1, without horn-like pro- jection or slender seta on distoventral comer of Distribution. Kaiser Wilhelm II Land, Palmer article 2. Mandibularpalp, article 2 with 2 setae; AKrecrhgiupeelleang,o,Soutahnedrn WOecdeadne.ll160S-ea3,85 mAntdaerpctthi.ca; twoipthoodutofstpraonlgp sIp-ianretiocunlaatret.iclMeax2.ilMlaaxi2llaen1d,opprood- Remarks. Nebuliella extrema is distinguished (female) 1-articulate. Thoracopod 8 endopod 5- from N. antarctica primarily on the basis of the articulate. Pleopod 1 exopod(female)with7short rostrum. The ratioofthe rostral flangeto exposed plumose setae, 1 1 longer plumose setae along keel is approximately 1:1 for N. extrema (and lateral margin and 4 terminal plumose setae. all other species of Nebaliella) and 3:1 for Pleopod6approximately0.5 x lengthofpleonite6. N. antarctica. The posterior margin of the Description of female holotvpe (without carapace extends to partially cover pleonite 5 as embryos). Body length (measured from anterior in Nebaliella caboti but differs from N. caboti margin of carapace to tip of furca, excluding with maxilla 2 having a 2-articulate endopod. setae) 8.23 mm; carapace: length 5.23 mm; Maxilla2 ofN. cabotihas a 1-articulate endopod. emarginate; dorsum convex; anterolateral margin Thepleopod 1 exopod (female)ofN. extrema has narrowly rounded, posterolateral margin more 17 19 short plumose setae compared to only 6 broadly rounded; depth 0.6 x greatest length; in Nebaliella declivatas. Thiele (1905) did 6.9 > length of rostrum; posterior margin reach- not mention a carina on the carapace of N. ing beyond pleonite 6; surface not sculptured, extrema and it was not illustrated by Cannon ventral surface ofdorsodistal margin with row of (11>3I). However, Ledoyer (1993) noted the small spines. Pleonitcs 2 7: margins entirely presence of a small carina on the anterolateral denticulate, denticles pointed. lower comer of the carapace of N. extrema, Rostrum: flange length 2.0 * width: length of Tsihmeilarmotsotthatsigpnoisfsiecsansted bdyiffNe.renbcreevicbareitnwaetean. okeferlos4t.r6al-fglraenagtee.stdepth ofkeel;keel 1.9 * length 7 1 REVIEW OI NEBAUBLLA (CRUSTACEA; LEPTOSTRAC'A) 45 Eyestalks: without ommatidia; dorsal margin plumose seta, length of exopod approximately convex; ventral margin extremely concave; taper- equal to endopod. Thoracopod 3: endopod ing distally; length measured in a straight line with single mesial row of plumose setae, from toptobottom ofeye; 1.1 x lengthofrostrum articles 3 5 with posterolateral setae, article including keel; length 3.0 x greatest width; with- 6 heavily setose along margin; exopod out dorsal papilla; without denticles; supraocular distally rounded, 0.5 ' length of endopod, scale absent. with evenly spaced plumose supracuticular Antenna I: article 1 without dorsal spine, as marginal setae. Thoracopod 8: endopod with wide as article 2; article 2, length 2.4 x width, 6 mesial and anterior plumose setae; exopod mesial plumose setae and numerous distal setae; tapering slightly, 0.6 x as long as endopod, article 3. 0.6 " length ofarticle 2, with 7 setae; with numerous plumose marginal setae. article 4 with a single row of 10 plumose setae Pleopods I-4: lateral margin of peduncle anteriorly; swollen scale, length 3.6 x width, denticulate; exopod 1-articulate; endopod 2- heavily setose, with plumose setae; flagellum articulate, article 1 with retinaculum, article 2 with 8 articles, setae clustered on anterodistal with fine, long plumose setae on lateral and marginofeach article; rudimentarysecond flagel- mesial margins. 1 robust smooth seta and one lum arising mesially from article 4. Antenna 2: short, stout spine terminally. article 2, small dorsal spine present; article 3 Pleopod 1: peduncle with 2 groups ofanterior length 1.3 x width, with 1 anterior and 2 lateral plumose setae, 4 short plumose setae mesodis- rows ofsetae; articles 3 and4 not fused; article4 tally, lateral margin with tiny spines: exopod, slightly longer than article 3, with 1 anterior and 0.5 « length ofpeduncle, 0.6 * length ofendopod. 2 lateral rowsofplumose setae; flagellum with 1 comb-row of7 short plumose setae along lateral articles. margin of exopod, 0.2 * length of exopod. 1 Mandibular palp 3-articulate: article 2 with longer plumose setae also along lateral margin, 4 2 medial setae; article 3, equal in length to article plumose setae terminally, mesial margin with 2, margins tapering slightly, 1 row of plumose numerous long, fine plumose setae. Pleopod 2: setae along posterior and distal margin, increas- peduncle with anterior row of 7 plumose setae, ing in length distally, short seta terminally; 4 small plumose setae mesodistally; exopod well developed molar process, without sctal 0.8 x length of peduncle, 0.7 * length of brush; mandibular incisor with 3 teeth. Maxilla endopod, lateral margin with 10 smooth setae, 1: sympod. endite 1 slightly rounded with 1 2 terminal setae, mesial margin with long, row of plumose marginal setae and 2 robust fine plumose setae. Pleopod 3: peduncle with spinulose setae; palp long, well developed, with anterior row of 5 plumose setae; 4 short 3 articles, 13 lateral setae and 2 terminal plumose mesodistal setae; exopod, 0.7 x length of setae; endite 2 broader than endite 1, with 1 peduncle, 0.6 x length ofendopod. 9 subcuticular rowofstoutsimplesetae, 1 row ofplumose setae, plumose setae, 2 smooth setae terminally. and single longer supracuticular plumose seta. mesial margin with long, fine, plumose setae. Maxilla 2: with 5 endites; endite 1 expanded Pleopod 4: peduncle with anteroproximal distally, margin with 2 rows of plumose setae; row of 7 plumose setae, 4 short plumose endite 2 rectangular with 2 rows of plumose mesodistal setae; exopod, 0.8 x length of supracuticular setae; endite 3 with 2 rows of peduncle, 0.7 / length of endopod. lateral supracuticular plumose setae; endite 4 approxi- margin with 1 1 simple setae, 2 terminally, mately half width of endite 3, with 4 plumose mesial margin with long, fine plumose setae. setae; endite 5 least developed, with 2 plumose Pleopod 5: singleramus, length 2.7 x width; with setae; endopod tapering distally, 0.85 * length of robust simple seta on terminal margin; fine exopod. 1-articulate; mesial margin of endopod plumose setae on lateral and mesial margin. with plumosesetae; lateral margin ofexopodwith Pleopod 6: single ramus, length 3.5 ' width; with plumose setae. 5 robust simple setae on lateral margin and 2 Thoracopods: endopods 5-articulate. folia- on terminal margin: small plumose setae on ceous, epipods absent. Ratio of endopods T1:T3 lateral and mesial margin. and Tl:T8 endopod: 1:1.7 and 1:0.9 respectively. Anal scales: triangular. Ratio ofexopods T1:T3 and T1:T8 exopod: 1:0.7 Caudal furca: length 3.3 * width; 1.5 * as andTh1o:r0a.5corpeospdectiveenldyo.podwith single mesial row wliotnhg a2s1 telssmoono,th0.3sextaeasonlonglataesralcarmaapragcien; of plumose se1t:ae, plumose setae also along and9 plumose setae onmedial margin, I terminal posterodistal margin; exopod, lateral margin with seta. WALKER-SMITH 46 G. K. Description of male allotype. Body length Thoracopods: endopods foliaceous, epipods 5.57 mm; carapace: length 4.70mm, 1.9 * width: absent. Ratio of endopods T1:T3 and T1.T8 dorsum convex; anterior margin rounded, 1:1.36and 1:1:0.6 respectively. Ratio ofexopods posterior margin more broadly rounded; depth T1:T3 and T1:T8 1:1.9 and 1:1.06 respectively. 0.6 * greatest length; length 4.6 * length of Thoracopod 1: endopod 6-articulate, with rostrum: posterior margin reaching anterior plumose setae along mesial margin; exopod region of pleonite 7; surface not sculptured; 0.8 x length of endopod. lateral margin with ventral surface of dorsodistal margin with plumose setae. Thoracopod 3: endopod 6- fine spines. Pleonites 2-7: margins entirely articulate. with plumose setae along mesial denticulate, denticles pointed; margin; exopod distally rounded, 0.9 x length Rostrum: flange length 2.0 x width; length of of endopod. with evenly spaced plumose supra- keel 3.5 x greatestdepthofkeel; keel 1.4 * length cuticular marginal setae. Thoracopod 8: endopod ofrostral flange. incompletely 5-articulate (articles 1 and 2 not Eyestalks: without ommatidia; dorsal margin completely separate) with plumose setae along convex;ventralmarginextremelyconcave;taper- mesial margin; exopod tapering slightly, 0.4 x as ing distally; 1.2 * length of rostrum including long as endopod, with numerous plumose keel; without dorsal papilla; without denticles; marginal setae. supraocularscaleabsent. Pleopods \^i posterior margin of peduncle Antenna 1: article 1 with dorsal spine; article denticulate; exopods 1-articulate: endopods 2- 2, length 2.5 * width. 8 mesial plumose setae articulate.retinaculumattachedtoarticle 1,article and numerous distal setae; article 3, with group 2 with long, fine plumose setae on lateral and of distal setae; article 4 with a single row mesial margins, 1 robust smooth seta and one of 7 plumose setae anteriorly; swollen scale short, stout spine terminally. narrower than for female, length 4.4 x width. Pleopod 1: pedunclewith singleplumose setae; distally setose, with plumose setae: flagellum exopod. 0.6 x length of endopod, comb-row longer than carapace, extending beyond end of of short plumose setae along lateral margin of caudal furca; rudimentary second flagellum exopod absent. 14 longer plumose setae along absent. Antenna 2; article 2. small dorsal spine lateralmargin, 3 plumose setae terminally, mesial present;article 3 withstoutandfinesetae; articles margin with numerous long, fine plumose setae. 3 and4 not fused; article 4. with 3 rows ofsetae. Pleopod 2: peduncle with anterior row of 7 1 lateral row of stout setae with adjacent finely plumose setae, single plumose seta distally; plumose setae and two rows of slender plumose exopod, 0.5 * length ofendopod. lateral margin setae: flagellum with many articles extending with 9 smooth setae, 2 terminal setae, mesial to caudal furca, heavily setose distally on each margin with long, fine plumose setae. Pleopod article. 3: peduncle with anterior row of 5 plumose Mandibularpalp: article 2 with no medial setae; setae;exopod,0.5 X length ofendopod, 6 subcuti- article 3, 1.3 * length ofarticle 2, margins taper- cularplumosesetae lateral, 3 smooth setae termi- ing slightly. 1 row ofplumose setae along poste- nally, mesial margin with long, fine, plumose rioranddistal margin, long setaeterminally; well setae. Pleopod 4: peduncle with anteroproximal developed molar process, without setal brush; rowof4plumosesetae. 2shortplumosemesodis- mandibularincisorwith3 modifiedteeth. Maxilla tal setae; exopod, 0.5 • length ofendopod. lateral 1: sympod, endite 1 narrowly roundedwitha sin- margin with 9 simple setae, 2 terminally, mesial gle row of9 plumose setae, decreasing in length margin with long, fine plumose setae. Pleopod 5: distally: endite 2 twice as wide as endite 1. uniramus. length 3.1 X width (not including slightly medially divided into two, each section peduncle); with 1 robust simple seta on terminal with 1 row of short marginal spines: palp long, margin: fine plumose setae, on lateral and mesial well developed, with 6 articles, 16 lateral setae margin. Pleopod 6: uniramus, length 3.3 * width and 2 terminal setae. Maxilla 2: with 4 endites; (not including peduncle); with 5 robust simple endite 1 margin with8plumosesetaeand 11 short setae on lateral and 2 on terminal margin; fine spines; endite 2 rectangular with 7 short spines; plumose setae on lateral and mesial margin. endite 3. with 5 plumose setae: endite 4 fused Anal scales: triangular. withendite 5.with 5 plumosesetaedistally: endo- Caudal furca: length 3.7 * width; 1.7 > as long pod2-articulate, tapering distally. 1.1 ' length of astelson, 0.3 * as long as carapace; with smooth exopod: mesial margin of endopod and lateral setae on lateral margin and plumose setae on exopod with plumose setae. mesial margin, 1 terminal seta. REVIEW OFNEBAL1ELLA (CRUSTACEA: LEPTOSTRACA) 47 bMF?i=gsuiwrahelo2lv.ieeNbweobodafyliae=nltl2eanmndmae;cl1icavan=tdaAsal,n,tfeAen2mn,aalMe2.DhAon=ltoet1ryimpoemr.;vDidoer=wsaRolfOvm,=aexw0..H5oafmmr1o,,smtaernu-dmj.MblXLea1tSe-craa1lvemsmea.w_oEf e-ye1stmamfc, 48 G. K. WALK.HR-SMITII Figure 3. Nebaliella declivatas, female holotype. Anterior view of thoracopod 1, thoracopod 3, thoracopod 8 and maxilla 2. Seale a = 0.5 mm.