RESEARCH，NO. 38: 55-63，2009 Atergαtis floridus (Linnaeus，1767) (: ): re-examination and correction of zoeal characters

Hironori Tanaka and Kooichi Konishi

Abstract .-The zoeal stages of floridus deposited in the Zoological Reference Atergαtis floridus (Linnaeus，1767) Collection，Ibaraki Nature Museum (INM- are re-examined in order to compare 1-007850-007852 ，007870-007872 ，007880 ・ the difference in morphological 007882，007890 ・007892) ，were prepared for descriptions between (Tanaka & the re-description of appendages. Three Konishi，2001) and (Clark & specimens were examined in each zoeal Paula，2003; Clark et al. ，2004). Some stage. The appendages were dissected corrections are made to our previous with fine insect pins using aNikon SMZ- zoeal description，and the up-dated 1000 stereomicroscope. Observations morphological characters of A. ftoridus and drawings were made under aNikon are compared with previously known Eclipse E400 microscope equipped with a zosimine zoeω. drawing tube. In the zoeal re-descriptions were illustrated only the characters to be corrected. Introduction The complete larval development of βoridus was described by Tanaka Re-description of zoeal stages & Konishi (2001) based on the material from Atergαtis ftoridus (Linnaeus，1767) ]apan. In recent years，the first zoea of A. (Figs. 1-4) βoridus was re-described from Singapore First zoea material by Clark & Paula (2003) and Clark Carapace (Fig. lA，B): Rostral spine et al. (2004) and was compared with our slightly shorter than dorsal spine，nearly previous description. The two accounts as long as protopod of antenna and distally differ with respect to spinulation on the spinulate .Anteromedian region without rostral spine ，length of the rostral spine ， setae. Carapace with apair of posterodorsal the terminal setation of the antennule，the setae. Eyes sessile. antennal endopod spine ，the number of Antennule σi g . lC): Uniramous，exopod terminal seta on the antennal exopod and unsegmented，conical ，with 2long ，2 short the two setal processes on the maxil1 ule aesthetascs and 1short terminal seta. basial endite (Clark & Paula 2003; Clark et Antenna (Fig .lD): Uniramous， al. 2004). The purpose of this paper is to protopodal process distally spinulate ， reappraise the first to fourth zoeal stages nearly as long as rostral spine. Endopod of A. βoridus，and to compare these with reduced to small spine (lD，arrow). Exopod previously reported zosimine zoeas. unsegmented，with 3unequal setae (2 unequal terminal and 1sma ll subterminal). Maxillule (Fig. lE): Coxal endite with 7 Materials and Methods setae .Basial endite with 2setal processes， The first to fourth zoeal stages of A. 2cuspidate spines and 3setae. Endopod 56 H. TANAKA &K KONISHI

C

E

Fig. 1. (Linnaeus ，1767): first zoea; 人 anterior view of carapace; B ， rostral spine ;C ，antennule; D ，antenna; E，maxillule. Scale: 0.1 mm.

2-segmented，with 1seta on proximal bilobed. segment，6 (2 subterminal + 4terminal) setae on distal segment. Third zoea Carapace (Fig .3A-D) :Dorsal spine with Second zoea 4・6 setae ，more small spines than in the Carapace (Fig. 2A-C): Dorsal spine second zoea. Anteromedian region with 5 with apair of setae ，a few small spines. pairs of anterodorsal setae. Each ventral Anteromedian region with 2pairs of margin with 6setae (1 plumose anterior seta anterodorsal setae. Eyes stalked. and 5posterior setae). Antennule (Fig. 2D): Exopod with 5 Antennule (Fig. 3E): Exopod with 6 aesthetascs and one seta. aesthetascs and one seta . Antenna (Fig. 2E): Enlarged except for Antenna (Fig. 3F): Endopod ca. 18% of exopod. Endopod evident as abud (2E， protopod. Enlarged except for exopod. arrow) . First maxilliped (Fig. 3G): Coxa with Third maxilliped (Fig. 2F): Present and 1plumose seta ，epipodal bud. Endopod rudimentary biramous. distal segment with 6(1 subterminal and Pereiopods (Fig. 2F): Present，chela 5terminal) setae. Exopod with 8plumose ATERGATIS FLORIDUS 57

E

F

Fig. 2. Atergatis floridus (Linnaeus ，1767): second zoea; A， anterior view of carapace; B ，rostral spine; C， dorsal spine; D ，antennule; E，antenna; F，third maxilliped and pereiopods. Scale: 0.1 mm.

natatory setae. Discussion Fourth zoea By careful re-examination of the first to Carapace (Fig. 4A-C): Dorsal spine with fourth zoeal stages，we observed anumber 10 setae ，more small spines than the in third of characters and made some corrections zoea. Anteromedian region with 6pairs of to our previously description (see Tanaka anterodorsal setae. & Konishi，2001). Consequently，we found Antenna (Fig. 4D): Endopod ca. 54%of that some zoeal characters were overlooked protopod. Enlarged except for exopod. in our previous description: spinulation First maxilliped (Fig .4E): Coxa with 2 on carapace rostral spine，setation and plumose setae and epipod present as abud. spinulation on carapace dorsal spine， Exopod with 10 plumose natatory setae. antennule setae ，antenna exopod setae and Second maxilliped (Fig. 4F): Coxa with endopod spine ，the presence of two setal epipodal bud. Exopod with 10 or 11 plumose processes on maxillule basal endite ，出 e buds natatory setae. of epipod and the appearance of the third maxilliped and pereiopods. 百le differences are summarized in Table 1. 58 H. TANAKA& K. KONISHI

D- ••••••••••••••• 「 - 「 nE u-

戸¥

Fig .3. Atergatis floridus (Linnaeus，1767): third zoea; A， anterior view of carapace; B，rostral spine; C， dorsal spine; D ，carapace ventral margin; E，antennule; F，antenna; G ，自 rst maxilliped. Scal e:0. 1mm

The first zoea of A. floridus from (Tanaka & Konishi，2001 ，Fig. 1A; present Singapore was re- described by Clark &Paula study，Fig .1A). This difference ，however ， (2003) and Clark et al. (2004) ，and differs may not be sign姐cant at the species leve l. It with respect to spinulation on the rostral has been reported that there is significant spine，the terminal setation of the anntenule， morphological variation in the length of zoeal the antennal endopod spine，the number of carapace spines of Cancer magister between terminal seta on the antennal exopod and Alaska and California specimens (Shiley et the two setal processes on the maxillule al. ，1987); these authors speculating that basial endite .The morphology of the first incubation temperature and period may zoea of A. floridus re-described by this study cause intraspecific variation. In the present agrees well with their characters. According case，it may be necessary to examine some to the description of Clark et α 1. (2004) ，the environmental variables in the reproduction rostral spine is shorter than the protopod of A. floridus. It is important to note that the of the antenna. However，the present result Singapore Ate培αtis lived and were hatched and the previous study show that rostral in atropical environment whereas those of spine is nearly as long as protopod of the present study were from atemperate antenna，agreeing with the original report zone. ATERGATIS FLORIDUS 59

'‘ '‘'‘

P 4 ••••I H 4 n - u - I ! J 4

‘ ¥、

Fig .4. Atergatis βoridus (Linnaeus ，1767): forth zoea; A， anterior view of carapace; B ，rostral spin e; C， dorsal spin e; D ，antenna ;E ，first maxilliped; F，second maxilliped. Scale :0.1 mm.

The xanthid subfamily Zosiminae now to the larval characters，A. germaini and the consists of nine genera with 69 species actaeine， tomentosus seem to be (Guinot，1967; Serene，1984 ;Ng & Huang， better placed within the Zosiminae rather 1997，Ng et α1. ，2008) and larval descriptions than Actaeinae，based on the presence of are lrnown for the following species: Atergatis three setae on the antennal exopod and reticul αtus ，A. floridus ，A. subdentatus ， similar lateral spines on the telson forks germaini，Lo Phozozymus picωr， (Clark et al. ，2004). 百le zoeas of L. pic 伽 eydouxi，Pl αtypodiellαspecωbilis ， are rather aberrant from what is known aeneus，Zozymodes xanthoides (see for other zosimines，since the rostral spine Terada，1980; Clark & Ng，1998; Tanaka， is without distal spinulation ，the lateral 1999; Fransozo et al. ，2001; Tanaka & carapace spines are lightly spinulate，the Konishi，2001; Clark & Paula，2003; Clark et antennal protopod is smooth and not armed al .，2004). with spinules，and the telson fork has two However，current of Zosiminae fine lateral spines (Clark & Ng，1998; Clark based on adult and first stage zoeal & Paula，2003; Clark et al. ，2004). morphological characters is dubious (Clark Unfortunately，the descriptions and et al. ，2004; Ng et al .，2008) .With respect illustrations of A. reticul αtus and Z. 60 H. TANAKA &K. KONISHI

Table 1. A comparison between the first to fourth zoea of Atergatis 月oridus described by Tanaka & Konishi (2001) and this present study.

Characters Tanal王a & Konishi (2001) Present study Firstzoea Carapace: spinules on rostral spine + Antennule: aesthetascs and seta 3a+1 4a+1 Antenna: exopod setae 2 3 endopod spine + Maxillule: basal endite 5 5and 2setal processes Second zoea Carapace: spinules on rostral/ dorsal spines + dorsal spine setae 2 Antennule: aesthetascs and seta 4a+1 5a+1 Antenna: exopod setae 2 3 endopod + τb i r d maxilliped: appearance of bud + Pereiopods: appearance of bud + τb i r d zoea Carapace: spinules on rostral/ dorsal spines + dorsal spine setae ι6 Antennule: aesthetascs and seta 5a+1 6a+1 Antenna: exopod setae 2 3 First maxilliped: coxa epipodal bud + Fourth zoea Carapace: spinules on rostral/ dorsal spines + dorsal spine setae 10 Antenna: exopod setae 2 3 First maxilliped: coxa epipodal bud + Second maxilliped: coxa epipodal bud + +:p陀 sent，ー: absent，a: aesthetasc. Table2. Acomparison oflarval characters in 出e first zoeas in thes ubfamily Zosiminae.

Characters Atergatis Atergatis Atergα，tis Atergato.舎sis Lophpzo砂抑制 Plal} ψodia h e - 引b ZOzy1ηodes a M 5 問 許制臥制 蹴 1 a 4 白 月oridus su bdentatus ticu lαtu s g plctor り'do spectabilis a c n xanthoid e s 3) 2) 6) 2) 2) p η 1) ，8) 2) b)

Carapace:

P剖 rof posterodor回 1setae + + ND + + + + ND + rostralsp in e- protopod of equal short ND short equal short long equal equal antenna length h spinules on ro stra lsp in e + + ND + + + ND + M 同2 spinul es onlat eralsp in es ND + ND 河 口 出 Antenna 吋 protopods pinulation + + ND + + + + + M endopod spine + + ND + + + + ND + R protopod- exopod % 15% 16% *6% 16 覧 10覧 16% 13% *2 1% 13 % O E Maxillule: u coxale ndite 7 7 7 7 7 7 7 6 7 g

basial endit e 5 加 d 2seta l 5 四 d 2small 5 5 叩 d2s mall 5and 2sma ll 5 回 d 2s mall 5 加 d2s m a ll 5 5 田 d 2s m a ll processes tee出 teeth teeth teeth teeth teeth

Fir st m axi lliped : coxa ND ND

Telson:

late ral comer 2sp(11arge + 2sp(1 large+ 11arge sp + 2sp(11arge+ 2 白ne sp 2sp(11arge + 2sp(11訂 ge+ 11 arge sp + 2sp(1 1ar ge + 1sma ll ersp) 1s maUersp) 1seta 1smalle rsp) (nots甘ong sp) 1sma ll ersp) 1s maUer sp) 1seta 1sma ll er sp)

会: esti mated 仕om自gure，sp: spi ne，+: present，-: ab sent，ND: no data 0> 1)'D加aka &Konishi (2001) ，2)Clark et al. (2004) ，3)Terada (1980) ，4) C lark & Ng(2004) ，5) T;加必m (1999) ，6) Clark & Ng(1998) ，7) Clark & Paula (2003) ，8) present study. 炉4 62 H. TANAKA&K. KON1SHl aeneus，by Terada (1 980) and Tanaka ， pictor (Fabricus，1798) (1999) respectively，are insufficient for (Crustacea，Decapoda ，Brachyura ，Xanthidae ， Zosiminae) with comments on familial contemporary standards of morphological ， characters for first stage zoeas. Zoosystema， comparative work. ln Atergαtis ，the first 20: 201-220. zoea of A. βoridus differs from A. reticulαtus 一一一一， & J. Paula，2003. Descriptions of and A. subdentatus by antennal protopod/ ten xanthoidean (Crustacea: Decapoda: exopod ratios. However，Aterg αtis is not Brachyura) first stage zoeas from Inhaca distinguished from other generaσable 2). Island ，Mozambique. TheRaffles Bulletin of ln the Zoiminae，all zoeal phase has Zoology，51 (2): 323-378. Ng & Ho -H. 2004. been documented in four species only: A. 一一一一， ，P. K. 1.， ，P. ， Atergatis subdentatus (De Haan，1835) ，Atergatopsis reticulatus βoridus ictor and Z. aeneus ，A. ，L. ρ germainia A. Milne Edwards，1865 and (Terada，1980; Tanaka，1999; Tanaka & Platypodia eydouxi (A. Milne Edwards，1865) Konishi，2001). ln the zoeal morphology at (Crustacea: Decapoda: :Xan 出idae: least，A. βoridus seems to be unique among Zosiminae) ー First stage zoeal descriptions other zosiminine zoeas by the appearance with implications for the subfamily. The of the small spines and setae on carapace Raffles Bul1 etin of Zoology，52: 563-592. dorsal spine at the second zoea (see this Fransozo，A.， Negreiros-Fransozo，M. L.， Martin， ]. w.， &Trautwein ，S. E. ，200 1. Morphology of study Figs. 2C，3C ，4C). the first zoeal stage of Platypodiella spectabilis ln the recent study，Atergatis ocyroe is (Harbst，1794) (Decapoda，Brachyura ， separated from A. βoridus by Ng & Davie Xanthidae) obtained in the laboratory. Gulf (2007). 百lese species have geographically and Caribbean Research，13: 79-85 ，Figs .1-3. discrete ranges; A. floridus is recorded from Guinot，D. ，1967 .Recherches pr eliminaires sur all Southeast Asia (with the exception of the les groupements naturels chez les Crustaces Andaman Sea and perhaps the west coast Decapodes Brachyoures. II I. A propos des affinites des genres Dairoides Stebbing et of Sumatra) ，the West Pacific and ， Daira De Haan. Bul1 etin du Museum National A. ocyroe from northern and western lndian d'Histoire Naturelle ，Paris ，2e ser. ，39: 540- Ocean (Ng & Davie，2007). The situation 563，Figs. 1-36 . requires that the differences between A. Ng，P. K. L.， & Huang，].-F.， 1997.Unrecorded βoridus and A. ocyroe in larval characters (Crustacea: Decapoda: Brachyura) from should be claritied. Taiwan and Tungsha Islands ，with description To elucidate the adult classification ， of anew genus and species of Xanthidae Zoological Studies Academia Sinica Taipei further study describing the larval ， ， ， 36: 261-276. characters of more related species is 一一一一， Guinot，D. ，& Davie，P. ]. F. ，2008. required. Systema Brachyurorum: Part 1. An annotated checklist of extant brachyuran crabs of the world. The Raff1 es Bul1 etin of Zoology. 17: Acknowledgements 1-286. Wethank two anonymous reviewers for 一一一一， & Davie，P. ]. F.， 2007. On the identity of the poisonous marine crab their giving us valuable advice and providing ，Atergatis floridus (Linnaeus，1767) and recognition of Atergatis literature. Weare greatly indebted to the ocyroe (Herbst，1801) as avalid species from curators and staff of the Ibaraki Prefectural the Indian Ocean (Crustacea: Brachyura: Ibaraki Nature Museum and the Oarai Xanthidae) .The Raffles Bul1 et in of Zoology， Aquarium for their kind support during the Supplement 16: 169-175. whole course of this s加 dy. Serene，R. ，1984 .Crustaces Decapodes Brachyoures de 1' 0cean Indien Occidental et de la Mer Rouge，Xanthoidea: Xanthidae Li terature Cited et Trapeziidae. Avec un addendum par Crosnier A.: Carpiliidae et Menippidae.Faune Clark，P. F. ，& Ng，P. K. 1.， 1998. The larval Tropicale ，24: 1-243，pls 1-48. development of the poisonous mosaic Shirley，S.M. ，Shirley ，T.C. ，& Ri ce ，S.D. ，1987 . ATERGATIS FLORlDUS 63

Latitudinal variation in the Dungeness crab， materia l. Crustacean Research. 30: 21-42. Cancer magister. zoeal morphology explained Terada，M. ，1980. Zoea larva of four crabs in the by incubation temperature. Marine Biology， subfamily Xanthinae. Zoological Magazine， 95: 371-376. 89: 138-148. Tanaka，H. ，1999. Zoeal development of the xanthid crab， (Linnaeus， 1758). Bulletin of Ibaraki Nature Museum，2: Addresses: (HT) Oarai Aquarium，Oarai ， 19-26. [In Japanesel Ibaraki 311-1301，Japan; (阻¥) National Research 一一一一， & Konishi，K ，200 1. Larval development Instituteof Fisheries Science，Fisheries Research of the poisonous crab Atergatis floridus Agency，Fukuura ，Ka nagawa 236- 8648，]apan (Li nnaeus，1767) (Crustacea，Decapoda ， E-mails:(HT)[email protected]; (KK) Xanthidae) described from laboratory-read [email protected]企c.go.j