EARLY ZOEAL STAGES OF PLACETRON WOSNESSENSKII AND RHINOLITHODES WOSNESSENSKII (, , LITHODIDAE) AND REVIEW OF LITHODID LARVAE OF THE NORTHERN NORTH PACIFIC OCEAN

EVAN B. HAYNES I

ABSTRACT

Stage I zoeae of Placetron wosnessenskii. and Stage I and Stage II zoeae of Rhinolithooes ",osnes­ senskii. which were reared in the laboratory. can be distinguished from other described zoeae of Lithodidae: P. wosnessenskii have long. blunt spines on posterior margins of abdominal somites 2-5 and sinuate curvature of long, blunt. posterolateral spines on abdominal somite 5; R. l

Crabs of the family Lithodidae constitute a major METHODS AND RESULTS component of the reptant decapod fauna of the northern North Pacific Ocean. Ofabout 25 species In March 1982, ovigerous females of Placetron ofLithodidae in the northern North Pacific Ocean. wosnessenskii and Rhinolithodes wosnessenskii larvae have been described. at least in part, were collected near Auke Bay, Alaska. in traps for eight species: Dermaturus mandtii Brandt, and by divers using scuba. The females were Cryptolithodes typicus Brandt. Hapalogaster transported to the laboratory and kept in filtered grebnitzkii Schalfeew, H. mertensii Brandt, Lith­ seawater (about 6e Cl until the zoeae hatched odes aequispina Benedict, Paralithodes brel'ipes about 1 wk later. After hatching, about 50 zoeae of (Milne Edwards and Lucas). P. camtschatica each species were transferred to each of four 4 I (Tilesius), and P. platypus Brandt. Most descrip­ glassjars containing about 2,500 ml ofseawater at tions are scattered in foreign scientific journals. 6.1e C. Seawater in the jars was changed about however, and published reviews of the larvae are every other day. Zoeae were fed live plankton limited in species and scope. This report describes strained through a 0.333 mm mesh. About 10 ml of and illustrates Stage I zoeae of Placetron ll'osnes­ live plankton was added to each jar every other senskii Schalfeew and Stages I and II zoeae of day. The live plankton consisted mostly of phyto­ Rhinolithodes wosnessenskii Brandt reared in the plankton and barnacle nauplii. A more detailed laboratory from ovigerous females. I characterize description of the rearing system and type and the morphological differences between zoeae of duration of illumination is given in Haynes and the Lithodidae and subfamily Pagurinae (family Ignell (19831. Paguridae), compare the morphology of lithodid Zoeae of Placetron wosnessenskii hatched at larvae of the northern North Pacific Ocean, and night, and samples ofzoeae were taken the follow­ provide keys for identifying the described larvae ing morning. No prezoeae of P. wosnessenskii to species and stage. were seen. Rhinolithodes wosnessenskii zoeae hatched at night and during the day, and those examined about 10 min after hatching had rem­ nants ofprezoeal exuviae attached to the cephalo­ 'Northwest and Alaska Fisheries Center Auke Bay Labora­ tory, National Marine Fisheries Service. NOAA. P.O. Box thorax and telson. The remnant exuviae are not 210155. Auke Bay. AK 99821. described in this paper. 315 Manuscript accepted October 1983. FISHERY BULLETIN: VOL. 82. NO.2. 1984. FISHERY BULLETIN: VOL. 82. NO.2 Although food was seen in the guts of some their appendages, techniques of illustration, and Placetron wosnessenskii zoeae, none molted to nomenclatureofappendagesfollow Haynes(1979). Stage II. Zoeae ofRhinolithodes wosnessenskii fed Carapace length refers to the straight-line dis­ actively and molted to Stage II about 20 dafter tance from posterior margin of eye orbit to mid­ hatching. Failure to change the seawater on dorsal posterior margin ofcarapace, excluding the schedule prevented rearing the zoeae of R. wos­ middorsal spine. Spines on the telson are num­ nessenskii beyond Stage II. bered from the outermost to innermost (medial) pair. Setation formulae are the number of setae DESCRIPTION OF ZOEAE per segment from the distal segment to the proxi­ mal segment. For clarity in the illustrations, Terminology, methods of measuring zoeae and. setules on plumose setae are usually omitted, but

A

1.0 mm

·O.S mm

RIGHT

E

O.S mm

O.S mm

FIGURE I.-Stage I zoea of Place/ron wosnessenskii: A, whole , right side; B. carapace, dorsal; C. antennule, ventral; D. antenna, ventral; E, mandibles (\ef!; and right>. posterior; F. maxillule, ventral; G, maxilla. dorsal; H. first maxilliped, lateral;

316 HAYNES: EARLY ZOEAL STAGES OF L1THODID CRABS spinulose setae are shown. Five zoeae were used to mm (range 5.90-6.70 mm, 10 specimens) (Fig. lA, verify segmentation and setation; 10 zoeae were B). Live zoeae orange throughout except for color­ usedfor measurements. Only those morphological less appendages and posterolateral spines on characteristics useful for readily identifying each carapace and abdomen. Carapace with medially stage are given. curved, long (>114 carapace lengthl, posterolat­ eral spines; markedly pronounced lateral ridges Placetro1J ·u'ostlessemkii-Stage I Zoeae and dorsoventral ridge; and two middorsal angu­ lar prominences: one near center of carapace and Mean carapace length, 2.12 mm (range 2.08­ other at posterior edge. No supraorbital spines. 2.21 mm, 10 specimens); mean total length, 6.22 Eyes sessile.

II

0.5 mm

1.0 mm

J

\\ \ \ 'W 1.0 mm 1.0 mm K

1.0 mm

I, second maxilliped, lateral: J. third maxilliped, lateral; K. pereopods 1-5. lateral: L. abdomen and telson, dorsal. 317 FISHERY BULLETIN: VOL. 82. NO.2 Antennule (Fig. 1C).-First antenna (antennule) segmented with four natatory setae. Endopodite with unsegmented tubular basal portion (pedun­ slightly longer than exopodite and distinctly five cle) and distal conical projection. Peduncle with segmented; setation formula 5. 3, I, 2, 3. Protopo­ ventral plumose seta. Conical projection with sev­ dite unsegmented with 10 setae. en aesthetascs and two simple setae terminally. Second maxilliped (Fig. 11l.-Similar to first Antenna

Maxilla lFig. 1G).-Second maxilla (maxilla) Mean carapace length, 1.29 mm (range 1.21-1.34 with platelike exopodite (scaphognathite). Exo­ mm, 10 specimens); mean total length, 4.45 mm podite with three long plumose setae terminally (range 4.02-4.62 mm. 10 specimens) (Fig. 2A, B). and a subterminal plumose seta on outer margin; Cephalothorax and base of maxillipeds orange; no proximal expansion of exopodite. Endopodite remainder ofmaxillipeds. most ofrostrum, and all unsegmented, setation formula 3, 1, 3. Basipodite of abdomen colorless. Carapace with middorsal and coxopodite bilobed. Basipodite with four setae angularprominence and spine at middorsal poste­ on distal lobe and five setae on proximal lobe. rior margin; medially curving, long (>1/4 cara­ Coxopodite with four setaeon distal lobe and eight pace length), posterolateral spines: markedly pro­ (sometimes seven) setae on proximal lobe. Fine nounced lateral ridge. No supraorbital or anal hairs on inner and outer margins of scaphogna­ spine. Eyes sessile. thite, outer margins ofendopodite, anddistal mar­ gins ofbasipodite and coxopodite. Antennule (Fig. 2C).-Distal conical projection unsegmented from peduncle. Peduncle with ven­ First maxilliped (Fig. 1H).-Exopodite partially tral plumose seta. Conical projection with seven 318 HAYNES: EARLY ZOEAL STAGES OF L1THODID CRABS

1.0 mm

O.S mm

LEFT II E

)( O.S mm

mm

G

F O.S mm

1.0 mm

FIGURE 2.-Stage I zoea of Rhinolithodes wosnessenskii: A. whole animal. right side: B. carapace. dorsal: C. antennule. ventral; D. antenna. ventral; E, mandibles (left and rightl. posterior: F. maxillule. ventral: G. maxilla. dorsal; H. abdomen and telson. dorsal. 319 FISHERY BULLETIN: VOL. 82, NO.2 aesthetascs and two simple setae lone terminal Antennule.-Distal conical projection segmented and one lateran. from peduncle.

Antenna IFig. 2D).-Antenna with inner flagel­ Antenna. -Tip of flagellum may have small lum and outer antennal scale: flagellum without spine. Antennal scale with seven plumose setae setae and shorter than scale. Antennal scale un­ along terminal and inner margins. jointed distally, fringed with six heavily plumose setae along terminal and inner margins, and Mandible. -Right mandible with five teeth be­ prominent spine distally on outer margin. Ventral tween incisor and molar processes. surface ofprotopodit~with spinulose spine at base of flagellum and smaller naked spine at base of Maxillille. -Basipodite with five terminal spines scale. lfour slightly spinulose>.

Mandible (Fig. 2E).-lncisor processes ofleft and Maxilla.-Scaphognathite with 11 plumose setae right mandibles a single tooth. Anterior margins on outer margin; no proximal expansion. Setation ofeach mandible with premolardenticles. No sub­ formulae ofendopodite 4, 1, 3. terminalprocessesormovablepremolardenticles. First and second maxillipeds. -Exopodite with Maxillille (Fig. 2Ft-Similarto Stage I Placetron seven natatory setae terminally. wosnessenskii except spines of basipodite less spinulose and proximal segment of endopodite Third maxilliped (Fig. 31.-Exopodite with six with two simple setae terminally instead ofone. plumose setae terminally. Endopodite with two plumose setae terminally. Maxilla (Fig. 2G).-Scaphognathite with seven long plumose setae on outer margin, no proximal Pleopods. -May be present as minute buds. expansion, setation formulae ofendopodite, basi­ podite, and coxopodite same as in Stage I Place­ Abdomen and telson. -Identical to Stage I except tron wosnessenskii. Fine hairs on margins ofbasi­ joint between somite 6 and telson indicated by podite and coxopodite. small indentation in lateral margins.

Maxillipeds 1-3 and pereopods 1-5. -Nearly iden­ tical inshapeand numberofsetae to thoseofStage I Placetron wosnessenskii.

Pleopods. -Absent.

Abdomen and telson IFig. 2A, Ht-Short blunt spines on abdominal somites 2-5; length of outer pair on somite 5 about 0.8 times maximum width of somite. Telson with medial invagination and 7 + 7 posterior spines. Third pair oftelsonic spines longest, about 3/4 maximum telson width; minute seta between spinal pairs 1 and 2 sometimes with­ out setules; spinules on spinal pairs 2-6. No uro­ pods or anal spine.

Stage II Zoeae

Mean carapace length, 1.30 mm (range 1.21-1.34 mm, 10 specimens); mean total length, 4.81 mm (range 4.02-5.03 mm, 10 specimens). No supra­ 0.5 orbital spine. Eyes stalked. Characters not men­ mm tioned are nearly identical to characters of Stage FIGURE a.-Stage II zoea of Rhinolithodes I. wosnessenskii: third maxilliped, lateral. 320 HAYNES: EARLY ZOEAL STAGES OF LITHODID CRABS DISTINCTION BETWEEN ZOEAE OF zoeae are characterized by sessile eyes, four nata­ LITHODIDAE AND PAGURINAE tory setae on maxillipeds 1 and 2; maxilliped 3 is undeveloped and without natatory setae; pleopods Zoeae of the family Lithodidae have long been and uropods are absent; and the telson and abdom­ considered similar morphologically to those ofthe inal somite 6 are fused. Beginning in Stage II. the subfamily Pagurinae (family Paguridae) and dif­ eyes are movable, and maxillipeds have at least fer only in reduction or disappearance of the six natatory setae. In Stage III, undeveloped uropods (Gurney 1942; MacDonald et al. 1957). pleopods and uropods are present, and the telson Recent descriptions of zoeae of Cryptolithodes and abdominal somite 6 are articulated. In Stage typicus, Lithodes aequispina, L. antarctica. and IV, the pleopods are biramous, and the uropods are Paralomis granulosa (Hart 1965; Haynes 1982; two segmented and usually have three or four Campodonico 1971; Campodonico and Guzman apical setae. Table 2 and the keys are provided for 1981) have extended the range ofzoeal characters distinguishing described zoeae and glaucothoe of of the Lithodidae and show that zoeae of the Lithodidae of the northern North Pacific Ocean. Lithodidae and Pagurinaecan be distinguished by Glaucothoe of H. grebnitzkii. P. wosnessenskii, size of the eyes and morphology of the carapace and R. wosnessenskii have not been described. and abdominal appendages (Table II. In general, zoeae of the Lithodidae (except Cryptolithodes TABLE 2. -Characters useful for distinguishing between Stages typicus) are characterized by stoutness, small I-IV of lithodid zoeae of the northern North Pacific Ocean. eyes. posterolateral spines in middle or lower half Paralithodes brel'ipes may have only three zaeal stages I Kurata 19561, thus. may not always conform to the descriptions in of carapace, uniramous uropods. and no anal this table. spine. Zoeae of the Pagurinae are characterized Stage by slenderness. large eyes, posterolateral spines Characteristic III IV in the middle or upper half of the carapace, Eyes sessile movable movable movable biramous uropods, and an anal spine. The glau­ Natatory setae cothoe of the Lithodidae and Pagurinae are read­ First maxilliped 4 "6 "6 "6 Second maxilliped 4 "6 "6 "6 ily distinguished from each other by their simi­ Third maxililped 0 "6 "6 "6 Pleopods absent absent absent or present larity to the adults (Haynes 1982). present as buds Uropods absent absent present; present; two unsegmented segmented TABLE I.-Characters useful for distinguishing between zoeae Telson and sixth of Lithodidae and zoeae of Pagurinae from the northern North abdominal somrte fused fused artiaJlated articulated Pacific Ocean. Zoeae of Cryptolithodes typicus ILithodidael are an exception and are not characterized in this table. Lithodidae Pagurinae Described Lithodid Zoeae of 1. General appearance, stoul. General appearance. slender. 2. Longitudinal diameter of eye Longiludinal diameter 01 eye the Northern North Pacific Ocean less than width of abdomen. greater than width of abdomen. 3. Posterolateral spines 01 Posterolateral spines of carapace 1a. Carapace without posterolateral spines; carapace in middle or lower in middle or upper half 01 posterior hall 01 posterior margin. margin. uropods absent in all stages; posteri­ 4. Lateral margins 01 carapace Lateral margins of carapace or margin of telson without medial nearly parallel. converge posteriorly. 5. No anal spine In any stage. Anal spine present until Stage III invagination Cryptolithodes typicus in some species. lb. Carapace with posterolateral spines; 6. More than eight pairs of Never more than eight pairs of uropods present in later stages (usually telsonic spines in some telsonic spines (excluding seta). species (excluding minute Stages III and IV); posterior margin of seta). telson with medial invagination 2 7. Uropods (when present) Uropods biramous; exopodite uniramous and terminal styliform terminally with usually 2a. Posterolateral spines of carapace short margin blunt with (usually more than three or four long setae « 1/4 carapace length) 3 three or four) short setae. along medial margin. 2b. Posterolateral spines of carapace long (> 1/4 carapace length) 5 3a. Posterolateral spines and denticles on MORPHOLOGY OF LITHODID abdominal somites 3 and 4 about same LARVAE length; posterior margins of carapace concave Hapalogaster grebnitzkii Lithodidae ofthe northern North Pacific Ocean 3b. Posterolateral spines obviously longer have four zoeal stages and a glaucothoe. Stage I than denticles on abdominal somites 321 FISHERY BULLETIN: VOL. 82, NO.2 3 and 4; posterior margin of carapace lb. Dorsal surface of carapace with spines convex 4 ...... 4 4a. Carapace length 1.2-1.4 mm; antennal 2a. Carapace triangular . flagellum and scale (including distal ...... Cryptolithodes typicus spine) about same length; antennal scale 2b. Carapace rectangular 3 ::S 5 times as long as wide . 3a. Lateral margin of carapace with teeth · Dermaturus mandtii in branchial region but not in hepatic 4b. Carapace length 1.4-1.7 mm; antennal region Hapalogaster mertensii flagellum longer than antennal scale 3b. Lateral margin of carapace with teeth (including distal spine); antennal scale in branchial and hepatic regions . about 9 times as long as wide ...... Dermaturus mandtii ...... Paralithodes brevipes 4a. Tips of anterolateral spines of rostral 5a. Carapace with middorsal posterior spine complex spinulose; most, if not all, · Rhinolithodes wosnessenskii spines on dorsal surface of carapace 5b. Carapace without middorsal posterior bifid Lithodes aequispina spine 6 4b. Tips ofanterolateral spines of rostral 6a. Antennal scale with ::S 6 markedly short complex styliform or bifid; most, if not « 1/2 scale width). lightly plumose all, spines on dorsal surface of carapace setae Hapalogaster mertensii styliform 5 6b. Antennal scale with 2': 6 long ( ~ 1/2 scale 5a. Carapace with 15 pairs of spines on width), heavily plumose setae 7 dorsal surface Paralithodes platypus 7a. Posterolateral spines of carapace project 5b. Carapace with < 15 pairs of spines on somewhatlaterally; telson has ~ 11 pairs dorsal surface 6 ofspines (excluding minutehair); longest 6a. Carapace with 14 pairs of spines on (third) pair of telsonic spines fused to dorsal surface .. Paralithodes camtschatica telson Lithodes aequispina 6b. Carapace with 13 pairs of spines on 7b. Posterolateral spines of carapace do not dorsal surface Paralithodes brevipes project laterally; telson has ::S 8 pairs of spines (excluding minute hair); longest Paralithodes brevipes may have three stages; (third) pair oftelsonic spinesjointed with thus, Table 2 may not always be appropriate for telson 8 distinguishing the stages of this species. Kurata 8a. Spineson posteriormargins ofabdominal (1956) reared and described the larvae of P. somites2-5 markedly long and tips blunt; brevipes from ovigerous females collected in Jap­ posterolateral spine on abdominal somite anese waters. In Kurata's description, P. brevipes 5 blunt and sinuate . has three zoeal stages instead of the four that · Placetron wosnessenskii characterize the . and Stage III zoeae cor­ 8b. Spines on posterior margins of abdom­ respond morphologically to Stage IV zoeae of the inal somites 2-5 typically short and tips genus. Makarov (1967), however, found four zoeal pointed; posterolateral spine on abdom­ stages of P. brevipes, including a Stage III zoea, inal somite 5 pointed and not sinuate .... 9 in plankton of the west Kamchatkan coast that 9a. Telsonic spines 8 + 8

Described Lithodid Glaucothoe of Only Stage I zoeae of Placetron wosnessenskii. the Northern North Pacific Ocean. and Stages I and II zoeae of Rhinolithodes wos­ Glaucothoe of Hapalogaster grebnitzkii, nessenskii have been described (this report). Placetron wosnessenskii, and Rhinolithodes Because these zoeal stages are morphologically wosnessenskii have not been described. typical of lithodid species with four zoeal stages, P. wosnessenskii and R. wosnessenskii like­ 1a. Dorsal surface of carapace without ly have the four zoeal stages characterized in spines 2 Table 2. 322 HAYNES: EARLY ZOEAL STAGES OF LITHODID CRABS Briefdescriptions and comparisons ofprevious­ are about the same length, and the scale is not ly described lithodid zoeae follow. more than five times as long as wide.

Cryptolithodes typicus. -Based on the descrip­ Hapalogaster mertensii. -Larvae of Hapalogast­ tion by Hart (1965), Cryptolithodes typicus zoeae er mertensii were collected from ovigerous fe­ are markedly different morphologically from males at Fidalgo Island, Wash.. and then reared other described lithodid zoeae. In C. typicus and described by Miller and Coffin (1961). Unfor­ zoeae, the carapace lacks posterolateral spines in tunately, their description is brief and lacks de­ all stages, the proximal expansion ofthe maxilla tail and, therefore, has limited value. Apparently, is present in Stage II, and the telson does not the only characters useful for distinguishing H. have a medial posterior invagination. In all other mertensii zoeae from zoeae of other lithodid spe­ lithodid zoeae, the carapace has posterolateral cies are size and number ofsetae on the antennal spines in all stages, the proximal expansion ofthe scale. In zoeal Stages I-III of H. mertensii, the maxilla is absent until Stage IV, and the telson antennal scale has six setae and. in Stage IV, four has a medial posterior invagination. The large setae. In all stages of H. mertensi.i, the setae are eyes of C. typicus, however, are typical ofzoeae of markedly short « ~ scale width) and lightly the Pagurinae, and the absence of posterolateral plumose. In most other lithodid zoeae, the anten­ spines on the carapace is similar to zoeae ofsome nal scale in Stage I has more than six heavily species of the Diogenidae. The shape ofthe telson, plumose setae that increase in number in later the fused abdominal somite 6 and telson in Stages stages, and the setae are as long as, or longer III and IV, and the absence of uropods in C. than, the width ofthe antennal scale. typicus are characters similar to those of some porcellanid zoeae. Lithodes aequispina. -Larvae of Lithodes aequi­ spina were reared and described from ovigerous Hapalogaster grebnitzkii, Dermaturus mandtii, females collected in waters of southeastern Alas­ and P. brevipes. -Makarov (1967 l briefly de­ ka

324