THE RAFFLES BULLETIN OF ZOOLOGY 2000 48(1): 17-29© National University of Singapore

DEVELOPMENTAL STAGES OF THE SPIDER CRABSCHIZOPHRYS PAKISTANENSIS TIRMIZI & KAZMI, 1995

(CRUSTACEA: DECAPODA: MAJIDAE)

Feroz Akhtar Siddiqui, Quddusi B. Kazmi and Nasima M. TirmiziMarine Reference Collection and Resource Centre, University of Karachi, Karachi-75270; Pakistan

ABSTRACT. - Through laboratory rearing and planktonic collections it has been possible to obtaincomplete larval stages of the spider crab Schizophrys pakistanensis Tirmizi & Kazmi, 1995, fromprezoea to the third crab stage. The larval and crab stages are described, illustrated and comparedwith larvae of the allied S. aspera reared by Kakati & Nayak (1979).

KEY WORDS. - Larval development, Schizophrys pakistanensis.

INTRODUCTION

On several occasions Schizophrys pakistanensis Tirmizi& Kazmi, 1995, hatched in the laboratory, prezoeae andzoeae but they did not survive. We are now able to obtainthe complete larval and juvenile stages from prezoeaeto third crab stage through laboratory rearing andplankton collection. The crab stages I-Ill were obtainedfrom a single megalopa from plankton sample. Thejuvenile crab stages of the genus Schizophrys were notpreviously known. Kurata (1969) was the first todescribe zoea I and megalopa of S. aspera, subsequentlyRice & Williamson (1977) described the second zoea.Later on the complete larval development of S. asperawas reported by Kakati & Nayak (1979) from the Indianwaters. Only two zoeal stages of S. pakistanensis (as S.

Table 1. Schizophrys pakistanensis: Details of Material.

aspera) from Pakistani waters were described by Tirmizi& Kazmi (1987). The present study deals with thecomplete series of larvae and three juvenile crab stagesof S. pakistanensis from Pakistan. The larvae arecompared with the existing account given by Kakati &Nayak, 1979. The zoeae and juvenile crab stages of S.pakistanensis are illustrated and briefly described.

MATERIAL AND METHODS

Schizophrys pakistanensis is quite common on the rockyshores of Pakistan. Ovigerous females are foundthroughout the year mostly at Buleji. Live specimenswere brought to the laboratory, their larvae were hatchedon five different occasions (Table 1).

Ovigerous females/ Hatched on Localitymegalopacollected on

Stages obtained Catalogue No.

22 JuI.1982 03 Aug.1982 Buleji prezoea BRAC 13403 Nov.1983 08 Nov.1983 Tusani prezoea BRAC24906 Jan.1986 same day Buleji prezoea and zoea 1 to 11 BRAC64115 Nov.1986 17 Nov.1986 Buleji zoea I to 11 BRAC64209 Dec.1989 megalopa Manora channel Crab I to III BRAC643280ct.1996 290ct.1996 Buleji zoea I only BRAC 132

Received 31 Dec 1998 Accepted 13 Mar 1999

17

Siddiqui et al.: Larval development of Schizophrys pakistanensis

Table 2. Successive changes in morphological characters of zoeae of S. pakistanensis Tirmizi & Kazmi, 1995

Character Prezoea (Fig. 1) Prezoea (Figs. 2-3) Zoea I Zoea 11early advanced (Fig. 4) (Fig. 5)

Carapace:spines absent buds present rostra!, posterior unchanged

& lateral presenteyes sessile sessile sessile stalked

Abdomen:segments incomplete 5-segmented 5-segmented 6-segmentedlateral spine absent buds present fully developed "pleopods absent absent protubrance present developed

Telson: undeveloped undeveloped developedfurca present furca with furca with unchangedsetae several setae on incomplete prongs complete prongs "

mesial and lateral 3+3 on mesial 3+3 on posteriormargin margin margin

lateral spine absent absent present present

Mandibles: not observed developed developed developedpalp not observed absent present

Antennule:aesthetascs not observed 4 unchanged 7setae 1 absent 1

Antenna:protopod not observed 1 terminal seta developed with unchanged

two rows of spinulesexopod three terminal setae unchanged unchangedendopod rudimentary bud unchanged more developed

Maxillule:setae: not developed developed unchangedcoxal endite not observed 6 7basial endite 6 7endopod 4 (2-segmented) 6(2-segmented)

Maxilla:seme: undeveloped developedcoxal endite 1+1 3+4basial endite 3+2 5+4endopod 3 5scaphognathite 2+2 14-16 26Maxilliped I undeveloped developed unchangedsetae:basiopod 7(2,2,1,2) 8(2,2,2,2) 9(2,2,2,3)endopod 7(2,1,0,1,3) 13(3,2,1,2,5) unchangedexopod 4(2-segmented) unchanged 6

Maxilliped 11:setae:basipod setae absent 3 unchangedendopod 2(3-segmented) 7(2-segmented) unchangedexopod 4(3-segmented) 4 6

Maxilliped Ill: rudimentary rudimentary bud rudimentary budfurther developed more developed

biramous bud biramous bud

Perepods rudimentaryfirst-fifth

18

THE RAFFLES BULLETIN OF ZOOLOGY 2000 48(1)

The females were kept in glass aquaria in seawater (36­37 parts per thousand salinity) at room temperature (17­24QC). The larvae, single megalopa and subsequent crabstages were kept in glass beakers (500ml) containingfiltered seawater. The beakers were examined daily andthe specimens were transferred to clean beakers filledwith freshly filtered seawater, and were fed on newlyhatched Artemia nauplii. For the crab stage, laboratorygrown seaweed (Viva fasciata) was also offered, withSargassum provided for shelter. The exuviae andspecimens of each stage were preserved in 5% bufferedformalin. Temporary slides were made using glycerineand formalin (3: 1) for further studies.

Measurements were made with a stage micrometer. Theabbreviation CL is used for carapace length measuredfrom the tip of the rostrum to the mid-posterior borderof the carapace.

Spent females and developmental stages are depositedin the Marine Reference Collection and Resource Centre,

University of Karachi.

RESULTS

During the five rearing experiments, the eggs of the threeovigerous females hatched into prezoeal stages includinghatching lot where only a few prezoeae were successfullymoulted into zoea I. The duration of these prezoeal stageswere not monitored. The eggs of other two ovigerousfemales were hatched directly into zoea I followed byzoea 11 as shown in Table 1. The duration between zoeaI to zoea 11 was 5 to 8 days. The megalopa moulted intocrab 1, stage within two days of its date of collection,the duration between crab I to crab III stages were 30 to31 days. Successive morphological changes withindifferent forms of zoeae are shown in Table 2.

Description ofthe Larvae. - The morphological accountfor developmental stages of S. pakistanensis is as follows.Prezoeal stages are presented only by illustrations.

\

8

A

EEc{)

o

o

'"33

O.5mm

Fig. 1. Schizophrys pakistanensis Tirmizi & Kazmi, prezoea early, A. lateral view; A'. telson; B. dorsal view.

19

Siddiqui et al.: Larval development of Schizophrys pakistanensis

EE

LL_ L.DW .crI 0

.........~

EE

LDc::i'«

O.25mm.

~

o

A",C,D,D'

A'

EE

LDc::i

8

A

Fig. 2. Schizophrys pakistanensis Tirmizi & Kazmi, prezoea advance. A. dorsal view; A'. rostrum and eye in lateralview; A". telson and last abdominal somite; B. antennule; C. antenna; D,D'. mandibles; E. maxillule; F. maxilla.

20

THE RAFFLES BULLETIN OF ZOOLOGY 2000 48(1)

EE

~L0IN

«0

\

.,\\\\

(

B

c

o

Fig. 3. Schizophrys pakistanensis Tirmizi & Kazmi, prezoea; advance. A. first maxilliped; B. second maxilliped; C.third maxilliped; D-G. first to fourth pereopods.

21

Siddiqui et al.: Larval development of Schizophrys pakistanensis

ZOEAI

Size.- CL = 1.8-2mm.

Carapace (Fig. 4A).-Dorsal spine curved backwardly;rostral spine nearly straight; lateral spines welldeveloped; eyes sessile.

Abdomen (Fig. 4'A).- With 5-somites; dorsally eachsomite with a pair of small setae; sixth somite fused withtelson; protuberance of pleopodal buds present; somite2 and 3 with well developed dorsolateral knobs;posteriolateral angles of somites 3-5 possess processesof equal length with bulbous ends. Telson furcated andwith a central indentation; each furca with an elongatedprong, each prong with a small lateral spine, a set of 3plumose setae present on either side of centralindentation.

Antennule (Fig. 4B).- Uniramous, conical and with fourlong terminal aesthetascs.

Antenna (Fig. 4C).- Protopod elongated, with smallspinules, arranged in two rows, distal half, exopodreaching to 3/4 length of protopod with 3 terminal setae;endopodal bud present and reaching to II2 length ofprotopod.

Mandible (Fig. 4D).- With well developed incisor andmolar processes; palp absent.

Maxillule (Fig. 4E).- Coxal and basial endites with 7and 6+ I plumodenticulate setae respectively; endopod2-segmented; proximal segment with I distal seta, distalsegment with I proximal and 4 terminal plumose setae.

Maxilla (Fig. 4F).- Bilobed coxal and basial endites with3+4 and 5+4 plumose setae respectively; endopodunsegmented with 5 plumose setae; scaphognathite with14-16 plumose setae.

Maxilliped 1 (Fig. 4G).- Basis with 8 (2,2,2,2) medialsetae, endopod 5-segmented with 3,2,1,1+1,1+4 plumosesetae and exopod with 4 natatory setae.

Maxilliped II (Fig. 4H).- Basis with 3 medial setae;endopod 3-segmented with 2,2,5 plumose setae; 4natatory setae on exopod.

Maxilliped III (Fig. 41).- Biramous, rudimentary bud.Pereopods.- Rudimentary buds.

ZOEA 11

Size.-CL = 2.5mm

Carapace.- Unchanged, with stalked eyes.

Abdomen.- 6-somites, armature unchanged.

22

Telson (Fig. 5A).- Separated from 6th abdominal somite;armature same as in zoea I.

Antennule (Fig. 5B).- With 7 aesthetascs and one seta;endopodal bud present.

Antenna (Fig. 5C).- Unchanged except endopodal budnearly equal to exopod.

Mandibles (Fig. 5D).- mandibular palps rudimentary.

Maxillule (Fig. 5E).- Unchanged.

Maxilla (Fig. 5F).- Coxal, basial and endopodal enditesunchanged; scaphognathite fringed with 26 marginalsetae.

Maxilliped 1and II (Figs. 5G & H).- Unchanged, exceptexopod with 6 natatory setae.

Maxilliped III (Fig. 51).- Rudimentary bud, unchanged.

Pereopods (Fig. 5J-N).- Rudimentary buds, unchanged.

CRAB I

Size.- CL=1.3mm.

Carapace (Fig. 6A).- Longer than broad, sparsely setose,lateral margin with 3 spines; rostrum bifid; eyes stout.

Abdomen (Fig. 6B).- Well developed with 7-somites(including telson) described by Tirmizi & Kazmi (1988)for adult specimen of both sexes; very thinly setose ascompared to adult specimens: telson not distinct.

Antennule (Fig. 6C).- Peduncle 5-segmented with veryfew setae; distal segment small and broader thanpenultimate segment, with 2-terminal flagella, lowerflagellum 2-segmented and setose, upper flagellum 5­segmented with many aesthetascs.

Antenna (Fig. 6D).- Distal segment with extended,bifurcated strong pronglike spine on distolateral angle;flagellum 7-segmented, sparsely setose.

Mandibles (Fig. 6E).- Well developed.

Maxillule (Fig. 6F).- Coxal and basial endites welldeveloped, with numerous setae; endopod 2-segmented,proximal segment with 1 and distal segment with 2terminal setae.

Maxilla. - Well developed.

Maxilliped 1(Fig. 6G).- Coxal and basial endites thinlysetose; endopod scapular shaped with few setae; exopod2-segmented with few setae on proximal segment, 4terminal setae on distal segment.

THE RAFFLES BULLETIN OF ZOOLOGY 200048(1)

.....,.

3:3

l ~~.~ \\\\\ \\ \\\ \ \ I, \

AA \\ 1\\ \ \i\ III I I

1\1\\\ \\1 \ i

\ \ ''i I

B~"li, I E E

E EL!) If)N Nd c>

G_I

B D_F

C

.0(Jl

:33

Fig. 4. Schizophrys pakistanensis Tirmizi & Kazmi, zoea 1. A. frontal view; A'. abdomen and telson in dorsal view; B.antennule; C. antenna; D. mandible; E. maxillule; F. maxilla; G. first maxilliped; H. second maxilliped; 1. third maxilliped.

23

Siddiqui et al.: Larval development of Schizophrys pakistanensis

,0N\Jl

:33

ppNNCJi Ul

3 33 3

EE

LD

o

Fig. 5. Schizophrys pakistanensis Tirmizi & Kazmi, zoea n. A. telson; B. antennule; C. antenna; D. mandibles; E.maxillule; F. maxilla; G. first maxilliped; H. second maxilliped; 1. third maxilliped; J-N. first to fifth pereopods.

24

THE RAFFLES BULLETIN OF ZOOLOGY 2000 48(1)

,A..B0.25 mmlmm

Fig. 6. Schizophrys pakistanensis Tirmizi & Kazmi, crab I stage. A. carapace with antenna and eyes; B. abdomen; C.antennule; D. antenna; E. mandibles; F. maxillule; G. first maxilliped; H. second maxilliped; I. second maxilliped; J.third maxilliped.

25

Siddiqui et al.: Larval development of Schizophrys pakistanensis

A I O.5mm

33

D

C ....1 ~

O.25mm.

A

EE

L..C)

d

B

Fig. 7. Schizophrys pakistanensis Tirmizi & Kazmi, pereopods of crab I stage. A. right cheliped, dorsomesial view; B.left cheliped, dorsolateral view; C. second pereopod; D. third pereopod.

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THE RAFFLES BULLETIN OF ZOOLOGY 2000 48(1)

Maxilliped II (Figs. 6H & 1).- Endopod 4 segmentedwith few setae on proximal segments and several on distalsegment varies in two specimens.

Maxilliped m (Fig. 61).- Ischium longer than merus,mesial margin denticulate; propodus, carpus and dactyluscylindrical and less setose than in adult (see Tirmizi &Kazmi, 1988); epipod long and setose.

Pereopods (Figs. 7A-D).- Chelipeds and walking legsless setose and with few tubercles as compared to adult

crab, illustrated by Tirmizi & Kazmi 1988: 178, fig. 5,5.

CRAB II & III

Size.- CL =1.7 mm & CL =1.8 mm respectively.

Carapace (Figs. 8B & C) pyriform, regions well marked;eyes reduced in size; number of spines and tuberclesfewer and setation less dense than in adult; bilobed budof gonopod (Fig. 8D) present in crab m stage (not

EE

EE

EE

EE

N

o

o

Fig. 8. Schizophrys pakistanensis Tirmizi & Kazmi, crab I-m. A-C. crab stages I to m respectively; D. gonopod, crab m.

27

Siddiqui et al.: Larval development of Schizophrys pakistanensis

observed in crab I & 11).

REMARKS

The adults of Schizophrys were referred till 1995 asbelonging to S. aspera and the larvae reported by Tirmizi& Kazmi (1987) as also belonging to S. aspera. Thelarvae of the same species were described from Japanby Kurata (1969) and from India by Kakati & Nayak(1979). These two descriptions differed so much thatKakati & Nayak (1979) suggested that either Kurata'smaterial was not identified correctly or some anotherspecies actually occurred in the Arabian Sea. Since their

Table 3. Comparison between Zoea I of Schizophrys.

first description of larvae of S. aspera from Pakistan,the species has been repeatedly reared (Table 1). Nowdifferences in curvature and length of rostral spine,number of antennular aesthetascs and length ofposterolateral angle of abdominal somite-3 have beennoted between the larvae reared here on differentoccasions, also differing greatly from S. aspera rearedin Japan but resembling to S. aspera reared in Bombay(Table 3). Since there were adults of two kinds a newspecies was established by Tirmizi and Kazmi, in 1995incorporating all the S. aspera so far reported from here.The two different types of larvae reared in the laboratoryare indicative of two species occurring here: one is S.aspera and the other is S. pakistanensis.

Pakistani specimens(S. pakistanensis)

Characters Present study

Indian specimens(S. aspera)Kakati & Nayak,1979

Japanese specimens(S. aspera)Kurata,1969

Carapace:lateralspine lengthrostral spine

Abdomen:posteriolateralsomite-3somite-5

Telson:tail furcalateralspines

Antennule:aesthetascsseta

Antenna:lengthendopodalbud lengthto protopod

Maxilla:scaphogna­tite setae

mediumrelatively small anddownwardly curved

largehalf way uptotelson fork

smooth

4I

1/3

14-16

28

largelong & straight

smallupto centralindentation

smooth

absent

3absent

1/3

14

smallsmall, downwardlycurved

largesmaller

barbed

3

3

1/4

not observed

THE RAFFLES BULLETIN OF ZOOLOGY 2000 48(1)

ACKNOWLEDGEMENTS

The first author (EA.S.) would like to express hergratitude to Dr. Patsy A. McLaughlin, Shannon PointMarine Centre, Western Washington University and alsois grateful to Dr. Peter K.L. Ng, Department of BiologicalSciences, National University of Singapore for criticallyreading the manuscript. Their suggestions are dulyincorporated.

LITERATURE CITED

Kakati, vs. & VN. Nayak, 1979. Larval history of the spidercrab, Schizophrys aspera (H. Milne Edwards)(Brachyura, Majidae) as observed in the Laboratory.

29

J. Bombay Nat. Hist. Soc. 76, 2: 259-267, figs. 1-4.Kurata, H., 1969. Larvae of decapod Brachyura of Arasaki,

Sagami Bay. IV Majidae. Bull. Tokai Reg. Fish.Res. Lab., 57: 81-127, figs. 1-27.

Rice, A.L. & DJ. Williamson, 1977. Planktonic stages ofCrustacea Malacostraca from Atlantic seamounts"Meteor" Forsch-Ergebn, 26: 28-64.

Tirmizi, N.M. & Q.B. Kazmi, 1987. Larval development oftwo spider crabs reared in the laboratory, familiesHymenosomatidae and Majidae. Crustaceana, 53(3):282-291.

Tirmizi, N.M. & Q.B. Kazmi, 1995. A new species ofSchizophrys from Pakistan with a note on Schizophrysaspera (Crustacea: Decapoda: Majidae). Proc. "Livingmarine resources and the environment" Karachi, 1993.M.F Thompson & N.M. Tirmizi (eds.), Pp. 136-141­figs 11.