Japanese Society JapaneseSociety of Systematic Zoology ofSystematicZoology Species Diversity,2000,5, 13-22 Zoeal Development of Novorostrum indicum (Crustacea:Decapoda: Porcellanidae) Reared under Laboratory Conditions Masayuki Osawa Department qf ZOotog]J, IVationalScienceMuseum. 7bltyo 3-231 Hyakunin-cho. Shinjuku-ku, 7bltyo,169-OO73Jtipan (Received 29 January 1999; Accepted 6 August 1999) development of the porcellanidcrab IVbvorostrum indicum is deillustrated from laboratory-rearedmaterial. Zoeal characters of this species appear to support the establishment of AJbvorostruin.FurtherP, joponicus, more, a closer affinity of this genus with Petroltsthesornatus, the larval and P. etongatus than with other species of Petrolisthes for which is known, and also the exelusion of P, ornatus frem morphology The zoea] scribed and IVbvorostrum, are Key Words: ment, supported, Crustacea, Decapoda, Arbvorostrum, Petrolisthes,zoeal develop- systematics. Introduction the larvaldevelopment of four species of Petrotisthes Stimpson, on the known larvae of the genus and assigned (1995)commented P. ornatus Paulson, 1875 and P. joponicus(de Haan, 1849) to his Group 1 and R elongatus (H.Milne Edwards, 1837) to his Group 2 based on the zoeal characters a new established (seeOsawa 1995: table5).Later,Osawa (1998) porcellanid genus, AJbvorostrum, definedby a combination of adult characters including:(1)carapace with uneven each region being divided into several gastric and branchial regions, lobe with trilobaterostrum, the median parts by grooves and sinuses, (2)distinctly lateral elevations, and (3)ocular peduncle distinctlybroader than cornea in dorsal indicus de Man, 1893 and two new view. To thisgenus Osawa assigned Petrolisthes species, AL decorocrus Osawa, 1998 and N phuketensis Osawa, 1998.However, he and P. elongatus commented that Indo-West Pacific species such as P. jqponicus shared several adult characters in common with IVbvorostrum, including: (1)sec- In a study on 1858, Osawa ond segment lipedwith of antennal peduncle lacking distinctanterior crest, (2)carpus of chewith broad tooth (lobe) in proxima] region of dorsoflexor margin (rarely two additional small teeth),(3)third maxilliped with robust exopod, and (4) somite with untapered endopod, those on male abdominal pleopods on second third to fifthabdominal somites reduced to small, produced buds. Further, alany specimens of R ornatus, he considered that though Osawa did not examine descripthis species might be assigned to IVOvorostrunzbased on Barnard's (1950) and the on the dorsal surface of the carapace tion and illustrations of structures one or median lobe of the rostrum. The larvae of species of AIOvorostrum were unknown until thispresent rearing NII-Electronic Library Service Japanese Society JapaneseSociety of Systematic Zoology Zoology ofSystematic 14 Masayuki Osawa stages of AL indicum in the laboratory.Here, the zoeal development of AL and itszoeae are compared with the Petrolisindicum is described and illustrated, adult-based rethes larvalgroupings proposed by Osawa (1995). Following that,the lationshipsbetween Petrolisthes and IVbvorostrum discussed by Osawa (1998) are testedusing larvalcharacters. of zoeal Materials and Methods Materials IVbvorostrum indicum were collected from the subtiKyushu, dal region ofa rocky beach in Bounotsu, Kagoshima Prefecture, southern Japan, on 26 June 1992. First-stage zoeae hatched on 9 July 1992, The spent female crabs and undissected and dissectedlarvae are deposited in the National Science Museum, Tokyo, under the registration numbers of NSMT-Cr 12513 and NSMT-Cr 12s14-12516, respectively. Two ovigerous females of Methods kept in round glass vessels (15cm in diameter and 12cm in height) in the laboratory.Hatched zoeae were reared in the same vessels was used for rearing, Water temafter cleaning of the bottoms. Filtered sea water and salinity were kept at 26.0-27.00C and 33.0-34.0%a, respectively. Zoeae perature hatched Artemia nauplii every day. The excrement of the larwere fed with newly vessel was mainvae was removed with a pipetteand the water in each rearing level the daily addition of sea water. tained at a constant by Larvae examined were fixed with 5"/bbuffered formalin fbr 2 hours and preserved in 70[Z,ethanol fbrmorphological observations. The observations and drawbinocular dissecting microscope equipped ings were made using a Nikon Optiphot with a drawing tube and done in 509,'hglycerine solution on a slide. Seven firstzoeae were dissectedfor setal observations. After obserstage and two second-stage vation, the dissectedappendages were mounted on slides using Hoyer's medium The and the cover slips were sealed with a Shiseido Overcoat clear nail varnish. is ordered from zoeal descriptionis based on the malacostracan somite plan and anterior to posterior.The appendage segments and setae on them are described from proximal to distaland in order of endopod to exopod. The long,plumose nataThe ovigerous crabs were maxillipeds are not fu11y illustory setae on the exopods of the first and second trated but are drawn truncated, Methods for measuring carapace length (CL),rosSetal tral spine length (RSL),and posterior spine length (PSL)fbllow Osawa (1995). in formulae for segments and distinctionsbetween setae and spines are shown Osawa (1997a), Results Although the reared larvae passed through two zoeal stages, they died before molting to the fbllowingphase (megalopa). The duration of the firstzoeal stage was 7 or 8 days under laboratory cenditions, while that of the second zoeal stage is unknown but seems to take more than 7 days because the pereiopods and pleopods of NII-Electronic NII-Electronic Library Service Japanese Society JapaneseSociety of Systematic Zoology Zoology ofSystematic Zoeal development of IVbvorostrum indicum the larvae were zoeae ond-stage not are fullydeveloped by that time. Descriptions given below. 15 of the first-and sec- Description IVOvorostrum indicum (deMan, 1893) (Figs1-4) First-stagezoea (Figs1,2) Size.CL 1.6-1.7mm (4 specimens), RSL 6.9-7.2mm (5specimens). (2specimens), PSL 3.0-4.0mm Caropace (Fig.IA, B). Typical porcellanid fbrm; rostral spine extremely elonwith numerous gate, spinules over entire length,length 4.6-4.7(2 specimens) times CL; posterior spines with spinules increasingin length proximally over entire ventralmargin, spines 1.8-1.9(3specimens) times Ionger than CL; posteroventral marIC) with 8-10minute spinules. Eyes sessile, gin (Fig. Antennule (Fig. 2A). Uniramous, elongate, slightly swollen, narrowing distally; endopod absent; exopod unsegmented with 3 aesthetascs and 3 setae at distalend. Antenna (Fig.2B). Biramous; endopod fused with protopod, bearing 1 subterminal seta, distalapex acutely tapering te acute apex, 1.3 pointed; exopod slender, times as long as endepod, with 1 or 2 subdistal spinules on mesial margin, Mandibles (Fig.2C). Asymmetrically dentate, incisorprocesses each with 1 strong tooth and several smaller teeth; molar processes serrate or spinose, with tuberculate ridges and small acute denticles; palp buds absent. Maxittule (Fig,2D). Coxal endite with 10 p]umodenticulate setae marginally; basal endite with 7 stout spines armed with several denticlesmarginally and 3 or 4 simple setae submarginally; endopod unsegmented with 1+1 setae, proximal seta very short and Maxitta spinule-like, distalseta long and stout. bilobed,proximal lobe with (Fig,2E). Coxal endite 4 submarginal and setae, distal lobe with 3 submarginal and 3 or 4 marginal setae; basal endite bilobed, proximal lobe with 3 submarginal and 5 or 6 marginal setae, distal lobe with 3 submarginal and 6-8 marginal setae, all setae on both endites plumodenticulate; endopod unsegmented, with 3+2+3 setae; scaphognathite with 9 or 10 4-6 marginal setulate plumose setae on anterior lobe and 5 setulate plumose setae on posterior lobe. First niaxilliped (Fig.2F). Biramous; coxa naked; basis with 2+2+2-3+3 setae on ventral margin; endopod 5-segmented, firstto fourth segments with 3, 3, 3, 5 ventral setae, respectively, firstto third segments with finesetules on dorsal margin, fifthsegment with 9 distal setae and 1 long, plumose seta at dorsoproximal angle; exopod indistinctly 2-segmented, distalsegment with 4 long, plumose natatory setae terminally. Second (Fig,2G). Biramous; coxa without setae; basis with 1+2 4-segrnented, first to third segments with 2, 2, ¢ tively, second and third segments with fine setules on dorfourth segment with 5 distalsetae and 1 Iong, plumose seta at dorso- maxilliped setae on ventral margin; 1+2 ventral setae, respe sal margin, proximal angle; Third exopod maxiltipeel endopod in firstmaxilliped. (Fig.2H). Small,biramous, as unsegmented buds. NII-Electronic Library Service Japanese Society JapaneseSociety of Systematic Zoology Zoology ofSystematic Masayuki Osawa 16 / -- "t=te=nyL .tttttt tttttttt ' ...J.tT[tFtTIEx,f..-v pt- .../pt'tS"ttttlX"-XE-". '.ts NZltk..'X th-. xt. ,,1 r-N 1 ..... 1 /iF. ... '' trff /1 7'･'t---･", Ax E D E.EG hl tt -am. ." .-./"-l,F7L-T6 B - ･"･ ttt ,.･･ . xx c" D Fig. 1. Nbvorostrurn indicum (deMan, 1893), firstzoea. A, domen and appendages, lateral;C, posteroventral margin lateral region, dorsal;F, same, telson, dorsal; E, telson, and distalpart of first posteriorseta of telson,dorsal. Scales ==O.1 Pereiopods. Small buds. Abdornen (Fig.ID), Five pair of posterolateral spines terodersalspines; fifthsomite carapace, lateral; B, carapace, lateral;D, of carapace, ab- abdomen region, dorsal;G, for A, B, 1.0 mm, posteremedian mm, except telson;second to fifthsomites each with small posincreasing in size posteriorly and with setae near bearing of short longest, posterolatpair somites and pleopod buds absent. breadth; pesteID). Approximately 1.4 times as long as maximum Telson (Fig. stout, setae bearing setules rewith 5 pairs of long, rior margin rounded, plumose placed distallyby distincthooklets (Fig.IG), these spinules decreasing in size as first(lateralmost)>second>third:=fburth=fifth plumose setae; posteromedian margin narrow, horizontal,bearing setules (Fig,IF); lateral angle with smooth spine mesial to base of lateralspine seta (anomuran hair) arising and short plumose fine setae along midline and single pair with 4 of IE); dorsal surface pairs (Fig. setae; bases of maranterior to base of third pair of margina] plumose somewhat ginal plumose setae each with 4 or 5 setules on lateral side; anal spine present. overall. Red chroRostra] and Cbtor in lijle. posterior spines pale brown eral margins; matophores seattered around mouthparts. Second-stage zoea (Figs3, 4) Size.CL 2,3-2.4mm (2 specimens), 2.1-2.5mm RSL unknown PSL because broken distally, (2specimens). zoea, Carmpace (Fig.3A), More infiatedthan in first-stage rostral and posterior NII-Electronic Library Service Japanese Society JapaneseSociety of Systematic Zoology ofSystematicZoology Zoeal development IVbvorostrum of "( //? K YKk t. indicum 17 -.L N - A.B c.p - trl - --;t>--tg..x ? xx / x. Fig, 2, fVovorostrum sal; C, mesial; mandibles, G, second , : - F, G.H - ventral; B, antenna, dorindicum (deMan, 1893), first zoea. A, antennule, internal;D, maxillule, external; E, maxilla, extervnal; F, first maxilliped, mesial; H, third maxilliped, lateral.Scales-O.1mm. maxilliped, with spinules as in first-stagezoea, posterior spine O.9-1.1(2 specimens) 3B). Eyes stalked. times as long as CL, posteroventralmargin with 4 spinules (Fig. midlength of lat4A). Biramous; with 2 short setae at Antennule (Fig, protopod endopod bud fused eral margin and 3 or 4 setae justproximal to base of exopod; spines NII-Electronic Library Service Japanese Society JapaneseSociety of Systematic Zoology ofSystematicZoology Masayuki Osawa 18 "XN'T-=tcL.e - .rr/ ,-.. ' N"t x N -xx !"Lt-s - B y.e'/ : ] '1"-----,t..N.. "/L,.7...1,[ x /L. .A ,Tl ff.r.h B r .si c MEEGH 1 .r. J va T 1 !illL /t ' d /9 3 -'C=> Fig. 3. AJbvorostrum (de Man, indtcum 1893), second /i i E A, zoea. carapace, abdomen and ap- of carapace, lateral;C, abdomen and telson, dorpendages, lateral;B, posteroventral margin sal; D, telson, lateralregion, dorsal;E, same, regien, dersal; F-H, distal parts posteromedian of first to third posterior setae of telson, dorsal; I, pleopod on second abdominal somite, lateral. Scales70.1mm, except for A, 1,O mm. protopod; with exopod thetascsnumbering with 3 setae. Antenna (Fig.4B). long 6 tiers bearing aesthetascs on mesial margin, aes4,3,3,2,3 from proximal to dista1tier,terminal margin with 4,3 or greatly lengthened, approximately Endopod as exopod, with 1 short acutely pointed;exopod with seta but 2 spinules no spinule near apex as to those in first- in size compared reduced 1,7 times 4C), distalapex (Fig. stage zoea. Mandibles Maxillule basal endite 4D). More (Fig. heavily dentatethan in firstzoea, lacking palp buds, (Fig.4E). Coxal endite with 10 plumodenticulate setae marginally, with 8 stout spines bearing several denticlesmarginally and 3 or 4 with 1+l setae. endopod Maxilla (Fig. 4F). Coxal endite with 4 submarginal and 5 or 6 marginal setae on and 4 marginal setae on distal lobe; basal endite proximal lobe,and 3 submarginal simple setae submarginally, with 3 submarginal and 7 marginal setae on proximal lobe and 3 submarginal and 7 or 8 marginal setae en distallobe,all setae on both endites plumodentieulate;en- dopod with 3+2+3 setae; scaphognathite with 21 setulate plumose setae margin- ally. Finst maxilliped (Fig.4G). Setation on basis as in first-stagezoea; endopod 5- NII-Electronic Library Service Japanese Society JapaneseSociety of Systematic Systematic Zoology Zoology of Zoeal development of AJbvorostrum indicum 19 the, / (6 1,ij ' ,i/i ' t/1 ttt ' " ' "'f 1 il t/ ' ' / 4r i/1[.gy " ll t,t il ' ' ] '!" ' 1 ' ' , vi / J1 , !/ ''' h'' ''/ ' ' L,,, t ' , , LLL /!l / x -- FC.D.E tix H.1 1/C, <SB rLC 1//// ' ttx '･t, x'X XEx<XX l it/ Y'/ ij ± A ""'i x 'w ix.X pa " ///'1,--L,1 x tig ,. rtt'/ ･V' /fl tt..t.. indicum (deMan, 1893), second ventral; D, distalpart of endopod, external; G, firstmaxilliped, mesial; Fig. 4. IVbvorostrum ventral; nal; C, same, F, maxilla, lateral. Scales=e.1mm, zoea. A, antennule, mandibles, H, second ventral; B, antenna, interznal; E, maxillule, maxilliped, mesial; exter- I, third maxilliped, NII-Electronic Library Service Japanese Society JapaneseSociety of Systematic Zoology Zoology ofSystematic 20 Masayuki Osawa dorsallong,plumose seta on each segment except fburth,setal fordistalsetae+dorsal plumose seta): 3+I, 3+ I,3+I, 5, 9+I, dorsal fine first to third segments disappearing;exopod indistinctly2-segmented, segmented, with mula (ventral or on distalsegment with 12 plumose natatory setae, proximal pair short. Second maxilliped (Fig,4H). Setation on basis as in first-stagezoea; setules segmented, with dorsal long, plumose seta on each segtnent mula: 2, 2+I, 1+2+I, 5+L dorsal fine setules on second and as in firstmaxilliped. maxilliped 4I), Endopod pearing; exopod Third naked; exopod (Fig, small, elongate, swollen, indistinctly 2-segmented, without endopod 4- first,setal fbrthird segmeiits disapexcept indistinctlysegmented, setae. Pereiopods(Fig.3A). Rudimentary, unsegmented, Abdomen (Fig.3C). Third to fifth somites each with posterolateral spines increasing in size posteriorly, second to fifthsomites with minute posterodorsal spines; pleopod buds (Fig. 3A, I) present on second to fifthabdominal somites, uniramous with endopods absent. 7'elson(Fig. 3C). As in first-stage zoea except for slightly reduced lateral spines 3D) and addition of of short setae lacking heok(Fig. posteromedian pair plumose lets in distalpart, unlike other 5 pairs (Fig. 3E-H). Color in lijl?. Similar to that of first-stagezoea. Discussion As was noted in the Introduction, Osawa (1998) considered that adults ef such Indo-West Pacific species as Petrolisthes and P, etongatus share several japonicus characters in common with Arbvorostrum, He also stated that P. ornatus might be attributed to AJOvorostrum after a directexamination of specimens. This hypothesis can now be tested using larvalcharacters. The zoeal stages of IVbvorostrum indicum ean be eompared with those of Group 1 of Osawa (1995), which comprises Petrolisthesornatus and R japonicus. These three species share six larval characters as fo11ow: in the first-stagezoea, (1)basis of maxillule armed with marginal 7 spines, (2)scaphognathite of maxilla bearing 4 or 5 long,plumose setae on the proxinial lobe, (3)5-segmented endopod of firstmaxilliped, and telson longer in than broad; and the second-stage zoea, (4) (5)absence of rudimentary mandibular palp, and (6)te]son provided with 6 pairs of long, setae on the posterior margin. NOvorostrum indicum also has five of these plumose characters in common with P. elongatus, which is the sole member of Osawa's be present in the (1995)Group 2, differingonly in that the mandibular palp may second zoeal stage of P. elongatus (seeWear 1964; Greenwood 1965). Therefbre, AC indicum appears to be close to both Groups 1 and2 of Osawa (1995) based on larval characters. Moreover, within Group 1, this species more closely resembles P. japonicusthan P. ornatus in:(1)coxa of firstmaxilliped without setae in first-and second-stage zoeae (withtwo setae in P, ornatus), (2)second and thirdendopod segments of firstmaxilliped each with 3 ventral setae in firstand second-stage zoeae segment of second maxilliped lacking (with4 setae in R ornatus), (3)firstendopod dorsal plumose seta in second-stage zoea, (4)first to fourth endopod segments of second maxilliped with 2, 2, 1+2, and 5 ventral setae in firstand second-stage zoeae 3 or 4, 3 or 4, 2+4, 6 setae in P. ornatus), exopods first of and second (with (5) NII-Electronic Library Service Japanese Society JapaneseSociety of Systematic Systematic Zoology Zoology of Zoeal development maxillipeds setae of with 12 plumose IVOvorostrum indicum natatory setae of third maxilliped in 21 second-stage zoea (with15 distalsetae in seczoea (with3 setae in P. ornatus) (seeYaqoob 1977; Osawa 1995). However, Groups 1 and 2 by having the exof AL indicum differs from Osawa's (1995) in P. omatus), ond-stage the zoea opod each of the antenna and with (6)exopod only small spines without the endopod and of the maxi]1ule with on the distal margin, In other porcellanidzoeae for which usually has 3-7 moderately is known, the endopod of the maxillule on the distal margin. long setae of Alovorostrunz To summarize the present larvalevidence, the establishment by Osawa (1998) is supported by these lasttwo zoeal characters, which distinguish 2 by Osawa IVOvorostrum indicum this genus from Groups 1 and (1995). proposed appears to be closely related to Petrotisthes ornatus, P. jmponicus, and P. elotzgatus in common with them, and consebecause itshares five or six zoeal characters than with other species of quently, ithas closer affinities with these three species isknown. Moreover, of the species in Petrolisthes for which the larval morphology Group 1, AL indicum resembles P, joponicusmore than P. ornatus based on the six additional shared zoeal characters mentioned above. This suggests that P. ornatus considered that P. should be excluded from IVDvorostrum, although Osawa (1998) ornatus might be assigned to this genus based on adult characters, that iseviOsawa (1995) pointed out the heterogeneityof the genus Petrolisthes dent in zoeal characters. Since that time, larvaldescriptionshave been published of this genus and two allied genera, Allopetrolisthes Haig, 1960 and on nine species Pachychetes Stimpson, 1858 (Albornozand Wehrtmann 1996; Wehrtmann et al, 1996, 1997; Osawa 1997a, b).Osawa (1995) expected that the type species of Petrolisthes,P. into his Group 6 based on the similarities of violaceus (Guerin, 1829),probably fa11s 1840) of that group. However, the the adult morphology with P. cinctipes (Randa]1, reveals that larvaldevelopment of P. violaceus provided by Wehrtmann et al. (1997) is the most speciose of the six this species actually belongs to Group 4.This group into Indo-West Pacificand New World larvalgroups and is generally subdivided zoea species by the structure of the lateral spines of the telson in the first-stage clearly needs heteregeneous and (Osawa 1997b). Although Petrolisthesremains of this genus and major revision, the intergeneric and interspecific relationships itsalliedgenera, including AJOvorostrum,can be gradually clarified by furtherlar- only a single stout seta the morphology val studies. Acknowledgments gratitude to Dr. M. Murano of the Instituteof Environmental Ecology, METOCEAN Co., Ltd,,and Dr. T. Ishimaru of the Tokyo Univerwas during this study. The manuscript sity of Fisheries,for their encouragement Dr, P. F. Clark of The Natural History Muimproved by the valuable comments of seum, London, and Dr. A. W. Harvey of Georgia Southern University. I express my sincere References Albornoz, L. and Wehrtmann, I. S. 1996, Aspects of the reproductive biology of Petrolisthes NII-Electronic Library Service Japanese Society JapaneseSociety of Systematic Zoology ofSystematicZoology 22 Masayuki Osawa laevigatus(Guerin,1835) (Decapoda,Anomura, Porcellanidae).Part II:Description of the larval development, including the firstcrab stage, cultivated under laboratory conditions. Arehive of Fishery nnd Marine Research 43: 137-157. Barnard, K. H. 1950. Descriptive catalogue of South African decapod Crustacea (crabsand shrimps). Annals of the South African Museum 3S: 1-837. Greenweod, J. G. 1965. The larval development ef Petrolistheselongatus (H.Milne Edwards) and PetroZisthes novaezelandiae Filhol (Anomura: Porcellanidae)with note on breedbig. Crustaceana 8:285-305. de Man. J. G. 1893. Report on the podophthalmous Crustacea,col]ected in the year 1891 by Dr. H. Ten Kate in some islands of the Malay Archipelage. Notes from the Leyden Museum 15: 284-311. Osawa, M. 1995.Larval development of four Petrolisthesspecies (Decapoda:Anomura: Porcellanidae) under laborator'yconditions, with comments on the larvae of the genus. Crustacean Research 24:157-187, Osawa, M, 1997a,Firstzoeae ef Pachycheles garciaensis (Ward)and Paclrychelessculptus <H. Milne Edwards) Porcellanidae) reared under labora(Crustacea: Decapoda: Anomura: tory conditions. Plankton Biology and Ecology 44:31-40. Osawa, M. 1997b, Zoeal development of four Indo-West Pacificspecies of the genus Petrolisthes (Crustacea: Decapoda: Anomura: Porcellanidae).Species Diversity2: 121-143. Osawa, M. 1998. AJbvorostrum,new genus (DecapodaiAnomura: Porcellanidae),with descriptions of three related species. Journal of Crustacean Biology 18: 161-176. Wear, R, G, 1964. Larvae of Petrolistheselongatus (H,Milne Edwards, 1837) (Crustacea: Decapoda: Anomura). Transactions of the Royal Societyof New Zealand 5: 39-53. Wehrtmann, I. S,,Albomlez, L., Pardo, M. and Veliz,D. 1997. The larval development of Retrolisthesviolaceus (Guerin,18:i1) (Decapoda, Anomura, Poreel]anidae)from Chilean waters, cultivated under laboratory conditiens. Crustaceana 70:562-583. Wehrtmann, I.S.,Albornoz, L.,Veliz,D. and Pardo M. 1996. Early developmental stages, inangulosus cluding the first crab, of AllQpetrolisthes (Decapoda:Anomura: Poreellanidae) from Chile,reared in the laboratory.Journal of Crustacean Biology 16:730-747. Yaqoob, M. 1977, The development o ± larvae ot' Petrotisthes ornatus Paulson, 1875 <Decapoda, , Porcellanidae) under laboratory conditions. Crustaceana 32: 241-255. NII-Electronic Library Service