THE COMPLETE LARVAL DEVELOPMENT IN THE LABORATORY OF MICROPANOPE SCULPTIPES (CRUSTACEA, , ) WITH A COMPARISON OF LARVAL CHARACTERS IN WESTERN ATLANTIC XANTHID GENERA1

BRYAN L. ANDRYSZAK2 AND ROBERT H. GORE3

ABSTRACT

The larval development in the laboratory of Micropanope sculptipes. a western Atlantic deepwater xanthid which inhabits encrusted and coralline substrates, is completely described and illus- trated. Development proceeds from a prezoeal stage of brief duration through four zoeal stages and one megalopa stage. Survival of larvae was poor under experimental conditions of die! illumination, 36/,, salinity, and temperatures of 20°, 25°, and 25°-30°C. Development to megalopa occurred only at 25° C. Morphological characteristics of M. sculptipes zoeae and megalopa are compared with larval charac- teristics of several other western Atlantic xanthid species.

Crabs of the family Xanthidae are both numerous been placed by Guinot in several other genera, or and diverse with species inhabiting a great variety await placement in genera yet to be named. of marine and estuarine environments (Rathbun Larvae of many species of xanthid from 1930). The Micropanope was erected by several different genera have been described Stimpson in 1871 with the type-species Mi- based on laboratory rearing, but there have been cropanope sculptipes. This genus consists of small no published descriptions of a complete larval de- (12 mm carapace width) xanthid crabs with a velopment for any species of Micropanope sensu known range from the Bahamas and Florida Keys lato thus far. A study on the larval development of to Brazil and Bermuda in deeper offshore oceanic M. barbadensis Rathbun has recently been com- water (Rathbun 1930; Guinot 1967). Micropanope pleted (Gore et al. 1981), but this species will ulti- was originally noted to resemblePi/urarms, and to mately be assigned to a separate, and as yet un- be allied withPanopeus, but was supposedly dis- defined, genus close to Coralliope (fide Guinot tinct in being a sublittoral to bathyal group and 1967). A knowledge of the larval morphology of not littoral as was Panopeus. However, subsequent Micropanope, when compared with larval charac- collections yielded Micropanope species which teristics of previously described xanthid species, were more littoral in distribution and, through especially those species once placed in the genus time, the genus was considered to be a heteroge- Micropanope, may be of some utility in recognizing neous mixture of several distinct generic groups the evolutionary relationships among such which were yet to be defined (Guinot 1967). This species within the Xanthidae. Accordingly, in this author emended the genus Micropanope to contain report we describe the complete larval develop- only two western Atlantic species: viz. M. ment of M. sculptipes from hatching to megalopa sculptipes Stimpson, the type-species, and M. stage based on specimens raised in the laboratory, lobifrons A. Milne Edwards. The remaining and compare these larval and postlarval stages species within Micropanope sensu lato have either with those from other xanthid crabs in the western North Atlantic.

MATERIALS AND METHODS 'Scientific Contribution No. 064, from the Smithsonian Institution, Fort Pierce Bureau, Fort Pierce, Fla. This report is Article XXI. Studies on Decapod Crustacea from the Indian A small (9.3 mm carapace width) ovigerous River Region of Florida. ^Smithsonian Institution, Fort Pierce Bureau, Fort Pierce. female M. sculptipes was collected 14 June 1978 by Fla.; present address: TerEco Corporation, 500 University West, the crew of the Harbor Branch Foundation KV Sea P.O. Drawer GF, College Station, TX 77840. ^Smithsonian Institution, Fort Pierce Bureau, Fort Pierce, Diver (cruise SD23, station #007), with a 20 ft (6.1 FL 33450. m) otter trawl. The trawl sample was taken off the Manuscript accepted January 1981. 487 FISHERY BULLETIN: VOL. 79, NO. 3, 1981. FISHERY BULLETIN: VOL. 79. NO. 3 coast of central eastern Florida between lat. Figure 1 and Table 1 indicate that survival was 27°14.8' N, long. 79°56.7' W and lat. 27*18.1' N, poor and was apparently influenced by tempera- long. 79°58.0' W from depths of 115.2-96.9 m. The ture. Most successful development occurred at 25° specimen, collected from a substrate consisting of C; survival was notably lower at 20° C, and no encrusted shell hash and Oculina coral, carried larvae developed beyond first zoeae at 25°-30° C. approximately 80 pale fuchsia eggs which dark- Even at the "optimum" temperature of 25° C, 50% ened slightly before hatching on 20 June in the mortality occurred during the first zoeal stage and laboratory. After yielding larvae, this specimen only one individual survived to the megalopa was compared with specimens ofM. sculptipes de- stage. At this temperature developmental dura- posited in the National Museum of Natural His- tion was 26 d from hatching to megalopa; no crab tory, Washington, D.C., which had been illustrated stage was attained. by Rathbun (1930: USNM 20719, 60777) and was The duration of larval stages was variable. First found to agree in all important respects. stage zoeae generally required 6 or 7 d to success- Three groups of 24 larvae were isolated, one fully molt to second stage zoeae; however, one in- each in 24 compartmented plastic boxes, and dividual at 20° C required 15 d and another indi- placed into controlled temperature units (CTU) at vidual at 25° C persisted for 10 d before molting. 20°, 25°,or 25°-30°C (±0.5°C) under diel illumina- These two zoeae did not survive beyond the second tion. Surf zone seawater (of 36%,) was filtered zoeal stage. Second and third zoeal stages gener- through glass wool fiber, stored in large Nalgene4 ally remained as such 5 d before molting, although bottles in the laboratory, and used to culture 20° C larvae took slightly longer than 25° C larvae. larvae. Fourth zoeal stages survived between 6 and 8 d Larvae received fresh seawater and were fed before either molting or dying. The one fourth freshly hatched San Francisco brand Artemia stage zoea at 25° C remained in stage 6 d before nauplii daily. Molts and deaths of each larva and molting to megalopa. color notes of representative larval stages under Larval development was apparently regular refracted and reflected white light were recorded. and no larvae were observed to either skip a devel- Dead individuals and molts were preserved in 70% opmental stage or molt without developing into a ethanol and were measured with a microscope more advanced stage. One zoea in the first stage at fitted with an eyepiece micrometer. Measurements 25° C was grossly deformed when it molted to given are the arithmetic mean values of the second stage at age 6 d and it died 7d later without number of specimens examined in each stage. molting again. All other zoeae possessed similar Larvae were cleared in 50% lactic acid solution to morphological characters, so that temperature which lignin pink stain was added to aid in draw- difference produced no variations. Many zoeae ing larval characters. Whole mounts (50 x) and died during preecdysis or in ecdysis to the next dissected appendages (drawn at 200 x and checked larval stage. Five of the nine fourth stage zoeae for details at 400 x) were mounted in CMCP died while attempting the molt to megalopae. mounting medium and drawn with Wild M5 and Megalopal telsons, antennae, and chelipeds were M20 microscopes equipped with camera lucidas. observed beneath the transparent fourth zoeal The spent female and a complete series of larval exoskeletons of these specimens, indicating a ter- stages are deposited in the United States National minal larval stage. No fifth zoeal stage larvae were Museum, USNM 171393. observed. The results of this study indicate that M. RESULTS OF REARING EXPERIMENT sculptipes larvae progress through four larval stages and thus are similar to the majority of Micropanope sculptipes larvae hatched as pre- xanthid species. Four zoeal stages have been con- zoeae of short, but not precisely determined, dura- sidered characteristic in Xanthidae (Hyman 1925; tion. They developed through four zoeal stages, Lebour 1928) and include many species, e.g., after which metamorphosis to a megalopa oc- . (Costlow and Bookhout 1961a), curred. Eurypanopeus depressus (Costlow and Bookhout 1961b), Rhithropanopeus harrisii (Chamberlain 1962), Hexapanopeus angustifrons (Costlow and ^Reference to trade names does not imply endorsement by the Bookhout 1966), Leptodius [= Pseudomedaeus] National Marine Fisheries Service, NOAA. agassizii (Costlowand Bookhout 1968),Neopanope 488 ANDRYSZAK and GORE: COMPLETE LARVAL DEVELOPMENT OF MtCROPANOPE SCUIJ>TIPES

2 4 6 8 10 12

a 80 : 25° u < > a: so — <

U. ao O / \ \ / u / O 20 \ /\Zoea ill ,'zo=0,V \ < 1 '-•, i » Megalopa N--24 /, , ••' , ,'\ 1X__ , sx , 10 a 14 16 IS 20 22 24 26 28

40

20 / \ , Zoea II ""V \zoea III '. N = 24 / \ Z A 6 B 10 12 14 |6 18 20 22 24 26 28 SURVIVAL IN DAYS

FIGURE 1.—Micropanope sculptipes. Percentage and duration of survival of larvae reared at three laboratory temperatures. N - number of larvae reared at each temperature in the series.

489 FISHERY BULLETIN: VOL. 79, NO. 3 TABLE 1.—Micropanope sculptipes, relative duration of larval ture increased. This inverse relationship between life in days at three temperatures. (Number of larvae started at temperature and duration of larval development is each temperature = 24.) consistently observed for the larvae of different Duration Total no. molting xanthid species (Costlow et al. 1962; Costlow and 6 C stage Minimum Mean Mode Maximum to next stage Bookhout 1971; Scotto 1979). Based on these data Zoea 1 5 7 15 6 and at 25° C, we may postulate a planktonic devel- Zoea II 4 5 5 5 Zoea III 5 7 2 opment time on the order of 1 mo before metamor- Zoea IV •6 — '6 0 phosis to first crab in M. sculptipes. Zoeal 5 6 10 12 4 5 5 9 Zoea III 4 5 5 9 LARVAL DESCRIPTION Zoea IV '1 6 '8 1 25-30 Did not survive beyond first zoeal slage First Zoea 'Died in stage without further molt. Carapace length (anterior margin of orbit to median posterodorsal edge of carapace): 0.47 mm. Number of specimens examined: 14. texana (McMahan 1967), N. sayi and N. packardii Carapace (Figure 2A, B). Typically brachyuran, (Costlow and Bookhout 1967), Pilumnus possessing rostral, dorsal, and 2 lateral spines. dasypodus (Sandifer 1974), andP. sayi (McDonald Eyes sessile. Rostrum straight, naked, sharply and Lang 1976). However, crabs of the genus pointed, slightly shorter than carapace length. Menippe develop through 5 or 6 zoeal stages prior Dorsal spine about equal in length to carapace, to metamorphosis (e.g., Porter 1960; Ong and curving gently posteriad, bearing a few scattered Costlow 1970; Scotto 1979), Heterozius rotundi- minute tubercles. Lateral spines short, naked, frons and Epixanthus dentatus have two zoeal projecting perpendicular to sagittal plane. stages, and Pilumnus lumpinus has only one zoeal Carapace elliptical, naked except for 2 small stage (Saba et al. 1978). The latter three species dorsolateral setae originating midway between live in specialized and restricted habitats which dorsal and lateral spines; mediodorsal knob may account for the differences in number of de- [= "forehead protuberance" Yang 1967] naked. velopmental stages. However, truncatus Antennule (Figure 2C). Flabellate rod with 3 (four zoeal stages) and Heteropanope (Pilum- aesthetascs, 2 naked setae at tip. nopeus) serratifrons (probably four zoeal stages) Antenna (Figure 2D). Protopodite long, tapering are also species which live in restricted habitats to point; spirally arranged spines present along (Wear 1968), so other factors besides environment distal three-fourths length with spines larger, may influence developmental time. Micropanope longer toward tip. Exopodite one-sixth to one-fifth barbadensis develops through either three or four protopodite length, naked throughout length, zoeal stages (Gore et al. 1981), and the elimination with 1 short apical spine, 1 long and 2 short apical of the "terminal" stage may be an adaptive nonplumose setae. response to food supply, nutritional deficiencies, or Mandibles (Figure 2E). Well-developed incisor an inherited response from adult genotypes, ac- and molar processes; no palp. cording to several hypotheses considered by these Maxillule (Figure 2F). Coxal endite with 7 stout, authors. plumose setae. Basal endite with 5 denticulate It is therefore difficult to directly compare the spines, about 20 minute hairs on lateral surface. duration of larval development for M. sculptipes Endopodite two-segmented; proximal segment (about 26 d at 25° C) with larval development with 1 long, nonplumose seta; distal segment with times for other xanthid species. Species of Menippe 2 subterminal, 4 terminal, sparsely plumose setae. (5 or 6 zoeal stages) required at least 17-21 d at 25° Maxilla (Figure 2G). Coxal enditebilobed with 4 C to develop into megalopa (summarized by Scotto proximal, 3 distal plumose setae. Basal endite 1979). The duration of larval development seems bilobed with 4 (occasionally 5) proximal and 4 to be largely dependent on temperature, and the distal plumose setae. Endopodite bilobed; 3 termi- experimental temperature conditions employed nal sparsely plumose apical setae on proximal by different researchers may vary considerably for lobe, 5 terminal (appearing as 3 apical, 2 slightly a number of reasons. Larval development time lower) sparsely plumose setae on distal lobe; this decreased for Micropanope sculptipes as tempera- setal formula holds for remainder of stages. 490 ANDRYSZAK and GORE; COMPLETE LARVAL DEVELOPMENT OFMICROPANOPE SCULPTIPES

1

0.5mm 0.1 mm A,B C-1

FIGURE 2.—Micropanope sculptipes, first zoea. A, ventral view; B, lateral view; C, antennule; D, antenna; E. mandibles; F, maxillule; G, maxilla; H, maxilliped 1; I, maxilliped 2.

491 FISHERY BULLETIN; VOL. 79, NO. 3

Scaphognathite with 4 marginal plumose setae Second Zoea and elongate sharp process bearing numerous minute hairs laterally. Carapace length: 0.61 mm. Number of specimens examined: 10. Maxilliped 1 ("Figure 2H). Coxopodite with 1 Carapace (Figure 3A, B). Eyes faceted, stalked. seta. Basipodite ventral margin with 10 sparsely Rostrum base with small, lateral preorbital pro- plumose setae arranged (proximally to distally) 2, tuberances perpendicular to longitudinal axis. 2, 3, 3; this setal formula holds for remainder of Dorsal spine usually with 2 small proximal setae, stages. Endopodite five-segmented with proximal occasionally with a few small widely spaced setae to distal segment setation of 2, 2,1, 2,4+1. (Roman and tubercles. Lateral spines with 2 to 4 minute numeral denotes dorsal seta.) Exopodite with 4 dorsal tubercles. Carapace ventral margin with 3 terminal natatory setae. or 4 fringing setae; mediodorsal knob now with 4 Maxilliped 2 (Figure 21). Coxopodite without integumental sensillae arranged into rectangle on setae. Basipodite ventral margin with one row of 4 crest, one pair setae anterior and posterior to sparsely plumose setae; this setal formula holds knob. for remainder of stages. Endopodite three- Antennule (Figure 3C). Four aesthetascs, 2 segmented with proximal to distal segment seta- naked setae at tip. tion of 1, 1, 4+1. Exopodite with 4 terminal nata- Antenna (Figure 3D). Unchanged except for in- tory setae. cipient endopodite primordium near exopodite base. Maxilliped 3 and Pereiopods. Not apparent. Mandibles (Figure 3E). As illustrated, without Abdomen (Figure 2A, B). With five somites. So- palp. mite 1 unornamented; somite 2 with anteriorly Maxillule (Figure 3F). Coxal endite unchanged curved lateral hooks; somite 3 with smaller poste- from first zoea. Basal endite apex with 6 denticu- riorly curved lateral hooks. Somites 3-5 with small late spines, 1 naked seta; lateral surface with 1 posterolateral spines overlapping following so- plumose seta, —20 minute hairs. Endopodite un- mite. Somites 2-5 with pair of minute pos- changed from first zoea. Protopodite now with 1 terodorsal setae. distal plumose seta. Maxilla (Figure 3G). Coxal endite bilobed with 4 Telson (Figure 2A, B). Bifurcate; each furca proximal, 4 distal plumose setae. Basal endite smooth, possessing one larger lateral spine near bilobed with 5 proximal, 4 distal plumose setae. its midlength and one smaller dorsal spine Scaphognathite with 11 or 12 marginal plumose originating near apex of lateral spine. Inner telson setae. margin with 3 pairs of articulated spines, each Maxilliped 1 (Figure 3H). Coxopodite with 1 armed throughout length with minute spinules, (rarely 2) seta. Endopodite unchanged from first center pair of spines with 2 longer interior zoea. Exopodite with 6 terminal natatory setae. spinules and 1 longer exterior spinule located at proximal one-third of spine. Inner telson margin Maxilliped 2 (Figure 31). Coxopodite without with pronounced medial sinus. setae. Endopodite three-segmented with proximal to distal segment setation of 1,1, 4 or 5+1. Exopo- Color. Zoea mainly colorless with exception of dite with 7 terminal natatory setae. localized pigment concentrations. Dorsal area of Maxilliped 3 and Pereiopods. Not apparent. orbit pale mint green, color fading into interor- bital area; interorbital protuberance faint orange. Abdomen (Figure 3A, B). With five somites. So- Gastric region pale orange extending along gut mite 1 with 1 posteredorsal seta; somites 2-5 gen- through first two abdominal segments (this color erally unchanged from first zoea, but posterolat- not due to ingested Artemia); diffused pale mint eral spines of somites 3-5 slightly longer relative green surrounds orange of gastric region. Mandi- to body size. ble incisor and molar surfaces scarlet, blending Telson (Figure 3A, B). Generally unchanged into pale orange within mandible. First and sec- from first zoea. An additional minute lateral fur- ond maxillipeds with diffuse pale orange at junc- cal spine may occasionally be present within the tion of basipodite and exopodite. Proximal region fork created by the major lateral spine where it of telson furcae on either side of median telson originates from the furca. This spine (when pres- sinus tinted with diffused pale orange. ent) may be readily apparent, reduced to a lump, 492 ANDRYSZAK and CORE: COMPLETE LARVAL DEVELOPMENT OF M1CROPANOPE SCULPTIPES

FIGURE 3.—Micropanope sculplipes,secondzoea. A, ventral view; B,lateral view; C,antennule;D, antenna; E, mandibles; F, maxillule; G, maxilla; H, maxilliped I; I, maxilliped 2.

493 FISHERY BULLETIN: VOL. 79, NO. 8 or present on one furca while absent from the other Maxilliped 3. Present as small, unbranched on the same individual. lobe. Color. Similar to that of first zoea, but noticeably Pereiopods (Figure 4B). Apparent as small rud- intensified. Pale orange highlights distal three- iments beneath carapace. fourths of rostrum, dorsal spine, antennae, and Abdomen (Figure 4A, B). Sixth somite present, antennules. Gut color more burnt orange, extend- lacking posterolateral spines and posterodorsal ing through abdominal somite 4. Mandibles most setae. Somite 1 with 2 or 3 posterodorsal setae; pronounced in burnt orange, outer surfaces somites 2-5 as in second zoea, but with posterolat- scarlet. eral spines of somites 3-5 progressively longer; somites 2-6 developing small pleopod buds; those Third Zoea of somite 6 barely apparent. Telson (Figure 4A, B). Median sinus with 2 Carapace length: 0.76 mm. small plumose setae. Secondary minute lateral Number of specimens examined: 8. furcal spines may or may not be present as in second zoea. Carapace (Figure 4A, B). Rostrum preorbital Color. Rostrum, dorsal spine, antennules, an- protuberances pronounced, angular. Dorsal spine tennae nearly colorless. Maxillipeds with pale with 3 (occasionally 2 or 4) small, scattered proxi- orange spreading through much of basipodites. mal setae with some scattered distal setae and Mandibles slightly darker burnt orange. Orbits minute tubercles. Lateral spines with 3 or 4 mi- pale mint green blending into faint sky blue at nute dorsal tubercles. Carapace ventral margin interorbital region. Sky-blue stellate chromato- with 2 or 3 setae. Mediodorsal knob with 2 or 3 phore at dorsal spine base. Vandyke-brown stel- additional smaller integumental sensillae located late chromatophore fringed in olive, mint green, within rectangular region previously demarcated sky blue at lateral spine bases. Pereiopod buds by 4 sensillae of second zoea; 6 setae anterior, 4 light orange. Gut burnt orange through somite 3, setae posterior to mediodorsal knob. with small spots of pale orange highlighting Antennule (Figure4C), With 3 aesthetascsandl pleopod buds on somites 3-5. naked seta at tip, 1 subterminal budlike projec- tion. Fourth Zoea Antenna (Figure 4D). Similar to earlier stage, endopodite more developed, with pointed tip Carapace length: 0.84 mm. slightly exceeding exopodite length. Number of specimens examined: 9. Mandibles (Figure 4E). As illustrated, without Carapace (Figure 5A, B). Rostrum preorbital palp. protuberances recurved into anteriorly directed Maxillule (Figure 4F). Coxal endite with 8 thick, hooks. Dorsal spine with 4 small proximal setae, plumose setae. Basal endite with 5 pectinate few scattered minute tubercles. Lateral spines as spines, 3 long sparsely plumose setae, 1 subtermi- in third zoea. Carapace ventral margin with 6-11 nal plumose seta, almost no minute hairs. En- (usually 9) setae. Mediodorsal knob with 4 outer dopodite as in first zoea. Protopodite with 1 distal sensillae (arranged as rectangle) surrounding 4 plumose seta. smaller inner sensillae; 10 setae anterior, 4 setae Maxilla (Figure 4G). Coxal endite bilobed with 5 posterior to knob. proximal, 4 distal plumose setae. Basal endite Antennule (Figure 5C). Biramous. Endopodite bilobed with 5 proximal, 4 distal plumose setae. half exopodite length, naked, pointed at tip. Endopodite as in first zoea except all setae naked. Exopodite two-segmented with 12 aesthetascs ar- Scaphognathite with 17 to 20 marginal plumose ranged proximally to distally (2, 6) (1, 3 apical) setae. plus 1 naked seta at tip. Protopodite swollen prox- Maxilliped 1 (Figure 4H). Coxopodite with 1 imoventrally, supporting 2 minute plumose setae. (rarely 2) seta. Five-segmented endopodite seta- Antenna (Figure 5D). Endopodite at least one- tion now 2, 2,1, 2, 5+1. Exopodite with 8 terminal half protopodite length. natatory setae. Mandibles (Figure 5E). As illustrated; palp Maxilliped 2 (Figure 41). Coxopodite without present. setae. Three-segmented endopodite setation now Maxillule (Figure 5F). Coxal endite with 11 or 12 1,1, 6. Exopodite with 9 terminal natatory setae. setae (small proximal seta occasionally absent). 494 ANDRYSZAK and GORE: COMPLETE LARVAL DEVELOPMENT OF MICROPAXOPE SCULPTIPES

FIGURE 4.—Micropanope sculptipes, third zoea. A, ventral view; B, lateral view; C, antennule; D, antenna; E, mandibles; F, maxillule; G, maxilla; H, maxilliped 1; I, maxilliped 2.

495 FISHERY BULLETIN: VOL. 79, NO. 3

FIGURE 5.—Micropanopesculptipes, fourth zoea. A, ventral view; B, lateral view; C, antennule; D, antenna; E, mandibles; F, maxillule; G, maxilla; H, maxilliped 1; I, maxilliped 2; J, maxilliped 3.

496 A NDRYSZAK and GORE: COMPLETE LARVAL DEVELOPMENT OF MICROPANOPE SCVLPT1PBS

Basal endite with 7 denticulate spines, 5 or 6 Megalopa sparsely plumose setae; few minute hairs. En- dopodite and protopodites as in third zoea. Carapace length (rostrum tip to median poste- Maxilla (Figure 5G). Coxal endite bilobed with 6 rior margin) x greatest width: 1.25 mm x 1.20 proximal, 4 distal plumose setae. Basal endite mm. bilobed with 6 proximal, 7 distal plumose setae, Number of specimens examined: 1. several minute lateral hairs on distal lobe. Carapace (Figure 6A-C). Slightly longer than Scaphognathite with 25 to 30 (usually 28 or 29) wide, subrectangular, somewhat inflated. Frontal marginal plumose setae. region produced, highly sculptured; rostrum prominent, acutely triangular, sharply rounded, Maxilliped 1 (Figure 5H). Coxopodite with 2 becoming broader at base, recurving anteriad into (rarely 1) setae. Endopodite as in third zoea. prominent anterolateral horns; latter one-half Exopodite with 9 terminal natatory setae. rostrum length, each with a small lateral spine Maxilliped 2 (Figure 51). Coxopodite with no bearing 2 small apical setae near base, oriented (rarely 1 very small) seta. Three-segmented en- perpendicular to longitudinal axis of horn. Four dopodite setation 1,1, 5+1 (rarely 4+1). Exopodite prominent plumose setae equal in length to ros- with 11 terminal natatory setae. trum project anteriorly between rostrum base and Maxilliped3 (Figure 5J). Greatly enlarged from base of each horn. Several smaller setae scattered third zoea, epipodite and endites well developed, in interorbital, gastric, and cardiac regions. One not yet segmented. small tubercle projecting near median posterodor- Pereiopods (Figure 5A, B). Greatly enlarged sal margin. Numerous setae fringe posterior and from third zoea, with incipient segmentation and ventrolateral margins. differentiation. Antennule (Figure 6D). Biramous; peduncle Abdomen (Figure 5A, B). Somite 1 with 3 pos- three-segmented; proximal article with 2 small terodorsal setae, slight posterolateral projections. plumose setae and 1 naked seta, penultimate arti- Somites 2-6 as in third zoea but pleopod buds en- cle with 1 naked seta, ultimate article with 2 small larged and biramous on somites 2-5, small and lateral setae and 6 nearly terminal, long, naked uniramous on somite 6. setae (arranged as 3 on either side of segmented flagellum). Ventral ramus with 3 terminal, 1 Telson (Figure 5A, B). Median sinus with 3 or 4 slightly subterminal, naked setae; dorsal ramus small plumose setae. Secondary minute lateral with aesthetascs progressing distally as follows: furcal spines may or may not be present as in (8), (6, +1 plumose seta opposite), (3 lateral, +3 second zoea. nonplumose setae near tip). Color. Rostrum, antennules, antennae pale Antenna (Figure BE). Peduncle with 3 lateral orange. Maxilliped 1 and 2 basipodites proximally setae, a distal lobe; setation (proximally to dis- with prominent burnt-orange stellate chromato- tally) on flagellar articles 1, 1, 0, 3, 4, 0, 0, 5. phores, diffused with pale mint green at Articles 5 and 6 slightly constricted at midlength, basipodite-exopodite junction. Mandible incisor may be partially segmented. and molar surfaces fringed in dark Vandyke brown blending into scarlet and burnt orange. Mandibles, maxillule, maxilla, and maxillipeds Orbits pale mint green. Sky-blue stellate 1 and 2. These were not dissected from the speci- chromatophore mixed with pale green and yellow men to prevent the destruction of the only at dorsal spine base. Lateral spines with burnt- megalopa obtained. orange and Vandyke-brown stellate chromato- Maxilliped3 (Figure 6F). Coxopodite and epipo- pbores blending into mint green distally. Body dite not exposed for examination. Basipodite par- (cephalothorax) generally pale yellow-orange tially exposed with at least 16 short setae. mixed with faint mint green. Gastric region and Endopodite five-segmented, setation progressing gut burnt orange extending through abdominal distally 16,14, 8,12,8 (5 lateral, 3 apical). Exopo- somite 3. Abdominal somites 2-5 with paired dite two-segmented; proximal segment with 3 lat- patches of pale burnt orange lateral to pleopod bud eral setae, distal segment with 1 subterminal seta origins, otherwise colorless. Telson entirely pale and 6 long, plumose terminal setae. orange diffused with mint green in vicinity of lat- Pereiopods (Figure 6A-C, 6G-I). All bear numer- eral and dorsal furcal spines. ous setae. Chelipeds (Figure 6G) similar, equal; FISHERY BULLETIN. VOL. 79, NO. 3

A-C D-K

FIGURE 6.—Micropanope sculptipcs, megalopa. A, dorsal view: B, lateral view; C, ventral view; D, antennule; E. antenna; F. maxilliped 3, G, cheliped; H, pereiopod 8; I, pereiopod 5; J, pleopod from abdominal somite 3; K, abdominal somite 6 with pleopods, telson.

498 ANDRYSZAK and GORE: COMPLETE LARVAL DEVELOPMENT OF MICROPANOPE SCULPT1PES coxa with small basal tubercle, ischium with large carapace setae, abdominal spination, telsonal fur- hooked spine and small dorsal tubercle. Bases of cae spination, and armature on basal segments of pereiopods 2-5 (Figure 6H, I) with small median the pereiopods. spine; dactyls of pereiopods 2-4 with a row of 3 Within the genus Micropanope (sensu lato), M. subterminal serrated spines, 1 terminal spine; sculptipes exhibits extremely close morphological dactylus of pereiopod 5 with 1 subterminal ser- similarity (but not developmental similarity) with rated spine, 3 long subterminal setae, 1 terminal the larvae of M. barbadensis (Gore et al. 1981). spine. Both species exhibit a type of antenna different Abdomen (Figure 6A-C). With 6 somites and from the four categories established by Aikawa telson. Lateral pleura of somites 2-5 slightly over- (1929) necessitating the creation of a fifth cate- lap following segment; lateral hooks of somites 2 gory, Type E (Gore et al. 1981). This grouping and 3 absent. Numerous setae cover dorsal sur- contains those larvae (presently only the two faces and posterodorsal margins of all somites. species here considered) in which the antennal Pleopods biramous (Figure 6J) on somites 2-5, exopodite is from one-fourth to one-seventh total uniramous on somite 6 (Figure 6K); exopodites protopodite length. Other features allowing dis- with plumose setae arranged (anteriorly to pos- tinction between the two species include (in M. teriorly) 15 or 16, 13 or 14, 13 or 14, 11, 7 or 8; sculptipes) the unadorned rostral carapace spine, endopodites of pleopods 2-5 with appendix interns shorter lateral spines, unpaired lateral spines on consisting of 2 terminal curved hooks. the telsonal furcae, a less lunate telson, more dis- Telson (Figure 6K). Roughly rectangular with 2 tinct spination on the antennal protopodite, a pairs of dorsal setae. Lateral margins produced single coxal seta on maxilliped 1, and the general posteriorly, forming slightly extended lobes, each distribution of fine hairs on the anterodorsal area lobe bearing 3 serrated spines of variable length; of the carapace. The position and number of in- posterior margin shallowly sinuous, with 3 tegumentary sensillae may prove to be of some plumose setae. value, but this feature in the genus has only been Color. The one megalopa died before color notes described for M. sculptipes. Gore et al. (1981) could be made. worked with molted carapaces in describing M. barbadensis and were unable to distinguish these DISCUSSION sensory pits clearly. A comparison of the larvae ofM. sculptipes with Comparative Morphology of Micropanope those in other western Atlantic xanthid species is sculptipes With Other Xanthid Larvae summarized in Table 2. The following differences appear salient. The preorbital rostral hooks of M. The Xanthidae is a large and heterogeneous sculptipes, which are fully formed in the fourth family containing many genera and numerous zoeal stage, are similar to, yet larger than, those species. As a consequence, the larval stages of described for Panopeus herbstii. Pseudomedaeus many such species from the Atlantic and Pacific [ex Leptodius] agassizii also possesses similar Oceans have been studied over a long period (e.g., "secondary rostral spines," but these are much Lebour 1928; Aikawa 1929,1937; Wear 1968; Saba more prominent from its second through fourth et al. 1978). In the western Atlantic, larval devel- zoeal stages. The rostrum of the other species opment is reliably known either completely or in noted (see Table 2) remains generally straight and part for at least 10 genera and 15 species, in addi- unarmed throughout development. tion to several other genera and species which are The antenna of M. sculptipes consists of a spi- less certain because identifications were based on nous protopodite and has an exopodite which is planktonic material. As might be expected, there one-sixth the protopodite length. The species in exist numerous characters, both shared and un- other genera possess an antennal protopodite shared, in the larval stages, so that comparison which is either nonspinous or noticeably less spi- among the species and genera is often quite diffi- nous than that of Micropanope. The antennal cult. Readily observable morphological characters exopodite of these xanthid zoeae fall into three useful in distinguishing zoeae and megalopae of general categories as described by Lebour (1928): M. sculptipes from other western Atlantic xanthid equal to protopodite length or Type A (Pilumnus species which may cooccur in the plankton include sayi, P. dasypodus); one-half to three-fourths pro- those of the rostral spine, antenna, anterodorsal topodite length or Type B (Menippe mercenaria, M. 499 FISHERY BULLETIN: VOL. 79, NO. 3

TABLE 2.— Comparison of morphologically important zoeal characters for distinguishing Micropanope sculptipes larvae from other western Atlantic species of Xanthidae based on descriptions and illustrations From different sources (only the first four zoeal stages of Menippe mercenaria and M. nodifrons are considered).

Anterodorsal Species carapace Abdomen Telson furca (source of description) spination spination

First zoea Micropanope sculptipes Straight, unarmed, Protopodite: spinous Posteralateral spines Furca smooth: * carapace length distal 3/4 somites 3-5 equal, 1 dorsal spine. Exopodite: 1/6-1/5 smooth 1 lateral spine protopodite length, Lateral hooks somites 2,3 3 apical setae Neopanope sayi Straight, unarmed, Protopodite: unarmed None figured Posterolateral spines Furca smooth: (Chamberlain 1961) 2% carapace length Exopodite minute, somites 3-5 equal, 1 dorsal spine apical seta smooth Lateral hooks somites 2,3 Neopanope texana Straight, unarmed, Protopodite: unarmed Posterolateral spines Furca smooth: (McMahan 1967) ^carapace length Exopodite minute, somites 3-5 equal, 1 dorsal spine apical seta smooth Lateral hooks somites 2,3 Neopanope packardii Straight, unarmed, Protopodite: sparsely None figured Posterolateral spines Furca smooth: (Costiow and Bookhout 1967) -carapace length spinous tip somites 3-5 equal, 1 dorsal spine Exopodite: minute smooth Lateral hooks somites 2,3 Panopeus herbslii Straight, unarmed, Protopodite: spinous None figured Posterolateral spines Furca smooth: (Costiow and Bookhout 1961a) carapace length tip somites 3-5 equal, 1 dorsal spine, Exopodite minute, smooth 2 lateral spines apical spine Lateral hooks somites 2.3 Eurypanopeus depressus Straight, unarmed, Protopodite: spinous None figured Posterolateral spines Furca smooth: (Costiow and Bookhout 1961b) 1.5 y carapace length distal 1/3 somites 3-5 equal, 1 dorsal spine Exopodite minute, smooth apical spine Lateral hooks somites 2,3 Hexapanopeus angustifrons Straight, unarmed, Protopodite: unarmed None figured Lateral hooks somites 2.3 Furca smooth (Costiow and Bookhau! 1966) 1.5x carapace length Exopodite minute Rhithropanopeus harrisii Straight, unarmed, Protopodite: minute None tigured Posterolateral spines Furca smooth: (Chamberlain 1962) 2.5 x carapace length spinules distal 1/4 somites 4. 5 prom in ant 1 dorsal spine Exopodite minute Lateral hooks somite 2 Pseudomedaeus agassizli Straight, unarmed, Protopodite: spinous None figured Posterolateral spines Furca smooth: (Costiow and Bookhout 1968) -^carapace length distal 1/2 somites 3-5 equal, 1 dorsal spine, Exopodite: 1/10 smooth 2 lateral spines protopodite Lateral hooks somites 2.3 length, 2 apical

Eurytium limosum Straight, unarmed, Protopodite: spinous None figured Posterolateral spines Furca smooth: (Kurata1) -carapace length distal 1/3 somites 3-5 smooth, 1 dorsal spine, Exopodite minute, subequal 1 lateral spine, apical seta Lateral hooks somites 2,3 1 minute lateral

Pilumnus sayi Unarmed, 1/3 carapace Protopodite: spinous None figured Postered or sal margins Furca spinous: (Kurata1) length distal 1/2 somites 2-5 serrated 1 dorsal spine, Exopodite = protopodite Lateral hooks somites 2 lateral spines length, spinous 2-5 distal 1/2,2 mfd- lateral spines Pilumnus dasypodus Unarmed, 1/3 carapace Protopodite: spinous None figured Posterodorsal margins Furca spinous: (Sandifer 1974) length distal 1/2 somites 3-5 serrated 1 dorsal spine, Exopodite • protopodite Lateral hooks somites 2,3 2 lateral spines length, spinous distal 1/2, 2 mid- lateral spines Menippe mercenaria Straight, unarmed, Protopodite: spinous None figured Dorsolateral spines Furca smooth: (Porter 1960) -- carapace length distal 1/2-1/5 somites 4, 5 1 dorsal spine, Exopodite: 3/4 protopo- Lateral hooks somites 2,3 1 lateral spine dite length, apical spine 1/2-3/5 exopo- dite length Menippe nodifrons Straight, unarmed, Protopodite: spinous Dorsolateral spines Furca smooth: (Scotlo 1979) * carapace length distal 1/2-1/5 somite 5 1 dorsal spine, Exopodite: 3/4 protopodite Lateral hooks somites 2,3 2 lateral spines length, apical spine 2/5 exopodite length ANDRYSZAK and GORE: COMPLETE LARVAL DEVELOPMENT OF M1CROPANOPE SCULPTIPES

TAK.E2.—Continued.

Anterodorsai Species carapace Abdomen Telson furca (source of description) Rostrum Antenna setae spination spination Second zoea Micropanope sculptipes Small preorbital Protopodite, exopodite 4 Unchanged2 Furca smooth. protuberances unchanged* 1 dorsal spine, 1 or 2 lateral spines Neopanope say/ Unchanged3 Protopodite, exopodite None figured Unchanged2 Unchanged2 (Chamberlain 1961) unchanged2 Neopanope texana Unchanged3 Protopodite, exopodite Unchanged2 Unchanged2 (McMahan 1967) unchanged2 Neopanope packardii Unchanged^ Protopodite, exopodite None figured Unchanged2 Unchanged2 (Costlow and Bookhout 1967) unchanged2 Panopeus herbstii Unchanged3 Protopodite, exopodite None figured Unchanged2 Unchanged2 (Costlow and Bookhout 1961a) unchanged2 Eurypanopeus depressus Unchanged2 Protopodite, exopodite None figured Unchanged2 Unchanged2 (Costlow and Bookhout 1961b) unchanged2 Hexapanopeus angustifrons Unchanged3 Protopodite, exopodite None figured Posterolateral spines Unchanged3 (Costlow and Bookhout 1966) unchanged2 somites 3-5 equal, smooth Lateral hooks unchanged2 Rhithropanopeus harrisii Unchanged3 Protopodite, exopodite None figured Unchanged2 Unchanged3 (Chamberlain 1962) unchanged2 Pseudomedaeus agassizii Secondary rostral Protopodite: None figured Unchanged2 Unchanged2 (Costlow and Bookhout 1968) spines spinous distal 1/3 Exopodite unchanged2 Eurytium fimosum Unchanged- Protopodite smooth, Not given Unchanged2 Unchanged2 (Kurata1) Exopodite unchanged2 Pilumnus sayi Unchanged? Protopodite, exopodite Not given Unchanged2 Unchanged2 (Kurata1) unchanged2 Pilumnus dasypodus Unchanged3 Protopodite, exopodite None figured Unchanged2 Unchanged2 (SandifeM974) unchanged2 Menippe mercenaria Unchanged2 Protopodite, exopodite None figured Posteroventral spines Unchanged2; (Porter 1960) unchanged2 somites 3-5: otherwise spines minute unchanged2 Menippe nodifrons Unchanged* Protopodite: unchanged2 4 Posteroventral spines Unchanged2L (Scotto 1979) Exopodite: spine somites 3,4: spines minute slightly longer posteroventral tooth somite 5; otherwise unchanged2 Third zoea Micropanope sculptipes Angular preorbital Protopodite: spinous 10 Unchanged2 Unchanged3 protuberances distal 2/3 Exopodite unchanged2 Neopanope sayi Unchanged3 Protopodite, exopodite None figured Unchanged2 Unchanged2 (Chamberlain 1961) unchanged2 Neopanope texana Unchanged2 Protopodite, exopodite Unchanged2 Unchanged2 (McMahan 1967) unchanged2 Neopanope packardii Unchanged2 Protopodite, exopodite None figured Unchanged2 Unchanged2 (Costlow and Bookhout 1967) unchanged3 Panopeus herbstii Small preorbital Protopodite. exopodite None figured Unchanged2 Unchanged3 (Costlow and Bookhout 1961a) protuberances unchanged3 Eurypanopeus depressus Unchanged2 Protopodite: spinous None figured Unchanged2 Unchanged2 {Costlow and Bookhout 1961b) tip Exopodite mimscule Hexapanopeus angustifrons Unchanged2 Protopodite, exopodite None figured Unchanged1' Unchanged2 (Costlow and Bookhout 1966) unchanged2 Rhithropanopeus harrisii Unchanged3 Protopodite. exopodite None figured Unchanged2 Unchanged2 (Chamberlain 1962) unchanged2 Pseudomedaeus agassizii Secondary rostral Protopodite, exopodite None figured Unchanged2 Unchanged2 (Costlow and Bookhout 1968) spines 1/3 rostrum unchanged3 length Eurytium Irmosum Unchanged2 Protopodite. exopodite Not given Unchanged2 Unchanged2 (Kurata1) unchanged-' Pilumnus sayi Unchanged2 Protopodite, exopodite Not given Unchanged2 Unchanged2 (Kurata1) unchanged2 Pilumnus dasypodus Unchanged2 Protopodite. exopodite None figured Unchanged2 Unchanged2 (Sandifer1974) unchanged2 Menippe mercenaria Unchanged2 Protopodite. exopodite None Unchanged3 Unchanged3 (Porter 1960) unchanged2 figured Menippe nodifrons Unchanged2 Protopodite. exopodite 4 Unchanged3 Unchanged3 (Scotto 1979) unchanged3

501 FISHERY BULLETIN: VOL. 79, NO. 3

TABLE 2.—Continued.

Anterodorsal Species carapace Abdomen Telson furca (source of description) Rostrum Antenna setae spi nation spination Fourth zoea Micropanope sculptipes Preorbital hooks Protopodite: spinous 14 Unchanged2 Unchanged3 distal 1/3 Exopodite unchanged3 Neopanope sayi Unchanged2 Protopodite, exopodite None figured Unchanged2 Unchanged2 {Chamberlain 1961) unchanged2 Neopanope texana Unchanged2 Protopodite. exopodite Unchanged2 Unchanged2 (McMahan1967) unchanged2 Neopanope packardii Unchanged2 Protopodite, exopodite None figured Unchanged2 Unchanged2 {Costlow and Bookhout 1967) unchanged2 Panopeus herbstii Small preorbital Protopodite; None figured Unchanged2 Unchanged2 (CosHow and Bookhoul 1961a) hooks unchanged2 Exopodite miniscule Burypanopeus depressus Unchanged2 Protopodite, exopodite None figured Unchanged2 Unchanged2 (Costlow and Bookhout 1961b) unchanged4 Hexapanopeus angustifrons Unchanged2 Protopodite: None figured Unchanged3 Unchanged2 (Costlow and Bookhout 1966) unchanged2 Exopodite miniscule Rhithropanopeus harrisii Unchanged2 Protopodite, exopodite None figured Unchanged2 Unchanged2 (Chamberlain 1962) unchanged2 Pseudomedaeus agassizii Unchanged4 Protopodite, exopodite None figured Unchanged2 Unchanged2 (Costlow and Bookhout 1966) unchanged3 Eurytium limosum Unchanged2 Protopodite, exopodite Not given Unchanged2 Unchanged2 (Kurata1) unchanged3 Pilumnus sayi Unchanged2 Protopodite, exopodite None figured Unchanged2 Unchanged2 (Kurata1) unchanged2 Pilumnus dasypodus Unchanged2 Protopodite, exopodite 1(7) figured Unchanged2 Unchanged2 (Sandifer 1974) unchanged2 Menippe mercenaria Unchanged2 Protopodite, exopodite None figured Unchanged3 Unchanged3 (Porter 1960) unchanged2 Menippe nodifrons Unchanged2 Protopodite, exopodite 8 Posterolateral spines Unchanged4 (Scotto 1979) unchanged2 somites 3, 4, dorso- lateral spines somite 5 longer

'Kurata, H. 1970. Studies on the life histories ol decapod Crustacea of Georgia. Unpubl. rep., 274 p. Univ. Georgia Mar. Inst, Sapeto Island. ^Character unchanged from first zoea. ^Character unchanged from second zoea. 'Character unchanged from third zoea.

nodifrons); minute or Type C (Neopanope sayi, N. stage II zoeae of Micropanope barbadensis (1-2), texana, N. packardii, Panopeus herbstii, stage III (4), and stage IV (12-14). Eurypanopeus depressus, Hexapanopeus angusti- Micropanope sculptipes zoeae have abdominal frons, Rhithropanopeus harrisii, Pseudomedaeus spination characteristics which consist of lateral agassizii, Eurytium limosum). The antenna! hooks on the second and third abdominal somites, exopodite of Micropanope sculptipes (Type E) is and smooth posterolateral spines on the third thus distinctive from other xanthid larvae both in through fifth abdominal somites. The posterolat- its length relative to the protopodite length, and in eral spines increase in length with each succeed- armature. Although the antenna of P. agassizii ing zoeal stage. This pattern of abdominal spina- closely resembles that of M. sculptipes, the pro- tion is similar to that observed for most other topodite is less spinous and the exopodite is one- xanthid species, but some species vary. tenth the protopodite length with two apical setae. Hexapanopeus angustifrons does not possess pos- The anterodorsal carapace (anterior half of the terolateral spines in the first stage, but develops dorsal carapace surface) setae of M. sculptipes them in subsequent stages in a manner similar to zoeae first appear in the second stage (2), and M. sculptipes.Rhithropanopeus harrisii possesses number 10 and 14 in the third and fourth stages, lateral hooks only on the second somite and con- respectively. Anterodorsal carapace setae are not spicuously long posterolateral spines on the fourth described for most of the other xanthid species; one and fifth somites. Pilumnus sayi has serrated seta is illustrated in the fourth stage of Pilumnus posterodorsal margins and lateral hooks on the dasypodus, and Menippe nodifrons develops 4 second through fifth somites, andP. dasypodus has setae during its second and third stages and 8 serrated posterodorsal margins on the third setae in its fourth stage. These setae are present in through fifth somites and lateral hooks on the 502 ANDRYSZAK and GORE: COMPLETE LARVAL DEVELOPMENT OF MICROPANOPE SCVLPT1PES second and third somites. Menippe mercenaria and broad, and generally rounded. The lateral spines M. nodifrons possess lateral hooks on the second of Neopanope sayi and N. texana are short and and third somites. Menippe mercenaria has a large there are 5 setae and 2 setae, respectively, between pair of dorsolateral spines on the fourth and fifth the rostrum and each lateral spine. Hexapanopeus somites, and develops posteroventral spines on the angustifrons and Eurytium limosum have promi- third through fifth somites in its second and sub- nent lateral horns which equal or exceed the ros- sequent zoeal stages. Menippe nodifrons has a trum length. Five setae and two setae are present large pair of dorsolateral spines only on the fifth between the rostrum and each lateral spine in H. somite, and develops posteroventral spines only on angustifrons andE. limosum, respectively. No lat- the third and fourth somites in its second and eral horns are found in R hithropanopeus harrisii subsequent zoeal stages. or Eurypanopeus depressus; 2 setae are found lat- Spination of the zoeal telson furca is varied eral to the rostrum in the former species while no among xanthid species. Micropanope sculptipes setae are present in the latter species. No lateral first zoeae have smooth telson furcae with 1 dorsal horns are found in Pilumnus sayi or P. dasypodus, and 1 lateral spine. Second and subsequent zoeal and 3 setae are present on either side of the ros- stages have furcae with 1 dorsal spine, and 1 or 2 trum in both species. The rostrums of Menippe lateral spines. Neopanope sayi, N. texana, N. pac- mercenaria and M. nodifrons are broad and have a kardii, Eurypanopeus depressus, and Rhith- distinct median cleft. No lateral horns or setae are ropanopeus harrisii have smooth telson furcae present in M. mercenaria, but bluntly angular in- with only 1 dorsal spine. Panopeus herbstii and terorbital protuberances and a few small, scat- Pseudomedaeus agassizii have smooth telson fur- tered setae are found in the frontal region of M. cae with 1 dorsal spine and 2 lateral spines. nodifrons. Hexapanopeus angustifrons has smooth telson fur- The telson of Micropanope sculptipes is rectan- cae without dorsal or lateral spines. Pilumnus sayi gular with 2 pairs of dorsal setae, 3 serrated spines and P. dasypodus have spinous telson furcae with at each posterolateral angle, and 3 plumose setae 1 dorsal spine and 2 lateral spines. The telson fur- along the shallow median telson sinus. Rectangu- cae of Menippe are smooth and bear minute spines; lar telsons are found in E. depressus, H. angusti- M. mercenaria has 1 dorsal and 1 lateral furca 1 frons, Pseudomedaeus agassizii, and R. harrisii. spines, and M. nodifrons has 1 dorsal and 2 lateral Eurypanopeus depressus has 3 short caudal setae furcal spines. with 2 longer setae on either side. Hexapanopeus Micropanope sculptipes megalopae may be angustifrons and P. agassizii have 2 to 4 short quickly distinguished from those of M. barbaden- setae and 4 short setae, respectively, along the sis, because the latter is presently the only species posterior telson margin. Rhithropanopeus harrisii within the genus which bears spines on the coxa- has a few short setae along its posterior telson bases and ischia; in M. sculptipes only the bases margin. Rounded (convex) posterior telson mar- are so armed. gins are found in N. sayi, M. texana, N. packardii, Micropanope sculptipes may be separated from Panopeus herbstii, and Eurytium limosum. other xanthid megalopae by examining the frontal Neopanope texana has 3 pairs of dorsal telson setae region ornamentation and telson structure (Table and 3 setae along the posterior telson margin, and 3). The frontal region of M. sculptipes is or- N. packardii has 8 stiff spines along its telson namented with a prominent rostrum and lateral caudal margin. Panopeus herbstii has 3 to 6 stiff horns; each lateral horn has a small lateral caudal telson spines. The telsons of Pilumnus sayi spine near its base. Four long, plumose setae lay and P. dasypodus are posteriorly rounded; P between the rostrum and each lateral horn. dasypodus has 2 dorsal and 2 ventral setae, and a Panopeus herbstii, Neopanope packardii, and posterior border which is generally unarmed. Pseudomedaeus agassizii have pointed, depressed Menippe mercenaria has a rounded and somewhat rostrums. The lateral spines (horns) of N. pac- truncated posterior telson margin. The telson of kardii are short, and the frontal region is devoid of M. nodifrons is subquadrate with 5 setae along its setae. Panopeus herbstii and Pseudomedaeus posterior margin; other telson setation is variable. agassizii have conspicuous lateral spines with 1 seta and 2 setae, respectively, between the rostrum Plesiomorphy and Larval Development and each lateral spine. The remaining species dis- cussed herein have rostrums which are reduced, Scotto (1979) provided a detailed discussion of 503 FISHERY BULLETIN: VOL. 79, NO. 3

TABLE 3.—Comparison of morphologically important mega [opal characters for distinguishing Micropanope sculptipes from megalopae of other western Atlantic species of Xanthidae based on descriptions and illustrations from different sources. Species (description source) Frontal region Telson

Micropanope sculptipes Rostrum prominent, sharply rounded Rectangular, 2 pairs dorsal setae, Lateral horns prominent, 1/2 rostrum length, small lateral 3 serrated spines at each outer corner, spines bearing 2 apical setae 3 plumose setae along shallow median sinus 4 long, plumose setae between rostrum and each lateral spine Neopanope sayi Rostrum square, depressed into blunt bifid tooth Rounded posteriorly (Chamberlain 1961) Lateral spines blunt 5 short setae between rostrum and each lateral spine Neopanope texana Rostrum blunt, depressed, notched Rounded posteriorly, 3 pairs dorsal setae, 3 (McMahan 1967) Lateral spines small, pointed posterior setae 2 short setae between rostrum and each lateral spine Neopanope packardir Rostrum long, pointed, depressed Caudal margin with 8 stiff spines (Costlow and Bookhout 1967) Lateral spines short, pointed No frontal setae figured Panopeus herbstii Rostrum stoutly pointed, depressed Rounded posteriorly, 3-6 stiff caudal spines (Costlow and Bookhout 1961a) Lateral spines stout, pointed slightly less than rostrum length 1 stout seta between rostrum and each lateral spine Eurypanopeus depressus Rostrum blunt, broadly triangular, depressed Rectangular, posterior margin with 3 short (Costlow and Bookhout 1961b} No lateral spines or frontal setae caudal setae. 2 longer setae on each side Hexapanopeus angustifrons Rostrum broad, rounded, depressed Rectangular, posterior margin with 2-4 short (Costlow and Bookhout 1966) Lateral horns prominent 5 short setae between rostrum and each lateral horn Rhiihropanopeus harrisii Rostrum blunt, depressed bifid tooth Rectangular, few short setae on posterior (Chamberlain 1962) No lateral spines margin 2 short setae on each side of rostrum Pseudomedaeus agassizii Rostrum pointed, depressed Rectangular, 4 short setae on posterior (Costlow and Bookhout 1968) Lateral spines stout, pointed, slightly shorter than rostrum margin 2 small setae between rostrum and each lateral spine Eurytium limosum Rostrum blunt, depressed bifid tooth Rounded posteriorly (Kurata1) Lateral horns prominent -•• rostrum length 3-4 setae between rostrum and each lateral horn, 1 outer lateral horn seta Pitumnus sayi Rostrum short, blunt, depressed Rounded posteriorly (Kurata1) No lateral spines 3 short setae on each side of rostrum Pilumnus dasypodus Rostrum broad, rounded, depressed Rounded. 2 dorsal, 2 ventral setae; posterior (Sandifer 1974) No lateral spines or frontal setae border unarmed (rarely with 1, 2 small medial spines) Menippe mercenaria Rostrum broad, depressed, shallow median groove Rounded, somewhat truncated posterior margin (Kurata1) No lateral spines or frontal setae figured Menippe nodifrons Rostrum strongly deflexed, biunt, rounded, distinct median Subquadrate, 5 setae on posterior margin, (Scotto 1979) cleft other setation variable Interorbital prominences lateral to rostrum angular, blunt

'Kurata. H, 1970. Studies on the life histories of decapod Crustacea of Georgia. Unpubl. rep., 274 p. Univ. Georgia Mar. Inst.. Sapelo Island. the importance of larval characters in determin- three distinctive groups: antennal exopodite ing phylogenetic relationships among brachyuran either minute, nearly equal to protopodite length, taxa. with special reference to the genus Menippe, or about three-fourths protopodite length. Shorter and the families Xanthidae and Cancridae. Al- antennal exopodites were considered indicative of though Lebour (1928) enumerated several distin- evolutionary more advanced species. guishing morphological characters of xanthid lar- Aikawa (1929) recognized four types of anten- vae, including number of zoeal stages, carapacial nae (A, B, C, D), also based on the relative length of armature, antennal morphology, abdominal mor- the peduncle (= protopodite) to that of the exopo- phology, and telson armature. Wear (1968, 1970) dite. In Type A the protopodite and exopodite are has shown that few of these are now valid. Even so, nearly equal in length, a condition considered the larval characteristics of Micropanope most primitive; in Type B the exopodite is one-half sculptipes generally agree with Lebour's classical to three-fourths of the protopodite length, a type categorization of morphological characteristics of characteristic of most brachyuran zoeae; in Type C the Xanthidae. Moreover, the antennal structure the exopodite is minute, these are the most highly of M. sculptipes differs in important respects, dis- developed. Type D antennae have a simple, incon- tinctive for the genus. spicuous spiny process which is shorter than Hyman (1925) and Lebour (1928) divided the either the rostrum or the antennule, and is consid- antennal morphology of xanthid larvae into two or ered to be a deviation. 504 ANDRYSSAK and GORE: COMPLETE LARVAL DEVELOPMENT OF MICROPANOPE SCULPTIPES

The antennal exopoditeof'larval M. sculptipes is panope is evolutionary more closely related to one-sixth to one-fifth the length of the protopodite, Panopeus than to Pilumnus. This finding supports and therefore may be considered an intermediate the contentions of Guinot (1967), and the apparent form in the antennal classification schemes of alliance between both larvae and adults of Hyman (1925), Lebour (1928), and Aikawa (1929). Micropanope and Panopeus emphasizes the im- The antennal configuration of M. sculptipes has portance which larval may have in de- been shown here to be distinctive from many other termining systematic and possible evolutionary xanthid larvae, and it may be a general charac- relationships within the complex family Xan- teristic of the genus Micropanope (sensu lato). This thidae. contention is supported by a nearly identical an- tennal configuration for zoeae of M. barbadensis. ACKNOWLEDGMENTS However, similar antennal morphological charac- teristics are seen in the larvae of Paramedaeus We wish to thank the personnel of the Smith- noelensis and Heterozius rotundifrons. This simi- sonian Institution Fort Pierce Bureau for provid- larity in antennal morphology allows establish- ing the materials and working space required for ment of a separate antennal classification typed this study. The senior author sincerely thanks "Group E" for larvae of the Xanthidae (Gore et al. Robert H. Gore for making possible the predoc- 1981). Larvae in this grouping might be consid- toral fellowship program, through which he was ered more advanced than most xanthids, although funded, and for providing the benefit of his exper- P. noelensis has four zoeal stages and is otherwise tise in larval development studies. Liberta E. similar in development to other members of the Scotto and Kim A. Wilson provided assistance in family. Heterozius has two zoeal stages but, as laboratory work and a great deal of encourage- noted by Wear (1968), may not belong in the ment. John Miller, Kim Wilson, Paula Mikkelsen, Xanthidae. Suzanne Bass, and the crew of the Sea Diver were responsible for collecting the ovigerous specimen Status of Micropanope in Family Xanthidae used in this study. Nancy A. Kuhn translated arti- cles written in French. Guinot (1967) discussed systematic relation- ships among adults of the Xanthidae and consid- LITERATURE CITED ered the genus Micropanope to be a mixture of several distinct generic groups which were inter- AIKAWA. H. mediate between the genera Panopeus and 1929. On larval forms of some Brachyura. Rec. Oceanogr. Pilumnus. She concluded Micropanope to be more Works Jpn. 2:17-55. 1937. Further notes on brachyuran larvae. Rec. closely related to Panopeus than toPilumnus. Oceanogr. Works Jpn. 9:87-162. A comparison of the overall larval morphology CHAMBERLAIN, N. A. of M. sculptipes with Panopeus herbstii and 1961. Studies on the larval development of Neopanope Pilumnus dasypodus (Table 2) reveals a much texana sayi (Smith) and other crabs of the family Xan- thidae (Brachyura). Johns Hopkins Univ., Chesapeake closer similarity between larvae of M. sculptipes Bay Inst., Tech. Rep. 22,35 p. and Panopeus herbstii than between M. sculptipes 1962. Ecological studies of the larval development of and Pilumnus dasypodus. Examination of the an- Rhithropanopeus harrisii (Xanthidae, Brachyura). tennal structure for these three species shows that Johns Hopkins Univ., Chesapeake Bay Inst., Tech. the length of the antennal exopodite relative to Rep. 28, 47 p. COSTLOW, J. D., JR., AND C. G. BOOKHOUT. that of the antennal protopodite for M. sculptipes 1961a. The larval stages at Panopeus herbstii Milne- (exopodite one-sixth protopodite length) is inter- Edwards reared in the laboratory. J. Elisha Mitchell mediate between the advanced state seen in Sci. Soc. 77:33-42. Panopeus herbstii (exopodite minute) and the 1961b. The larval development, of Eurypanopeus depresses (Smith) under laboratory conditions. Crustaceana primitive state seen in Pilumnus dasypodus 2:6-15. (exopodite equals protopodite length), being more 1966. Larval development of the crab, Hexapanopeus similar to Panopeus herbstii. Assuming that the angustifrons. Chesapeake Sci. 7:148-156. antennal exopodite relative length is an indicator 1967. The larval stages of the crab, Neopanope paekardii of the degree of relative primitiveness among (Kingsleyl, in the laboratory. Bull. Mar. Sci. 17:52-63. 1968. Larval development of the crab, Leptodiua agassizii xanthid species (Lebour 1928; Aikawa 1929), it can A. Milne-Edwards in the laboratory (Brachyura, Xan- be concluded on this larval character that Micro- thidae). Crustaceana Suppl. 2:203-213. 505 FISHERY BULLETIN: VOL. 79, NO. 3

1971. The effect of cyclic temperatures on larval develop- development of the stone crab, Menippe mercenaria (Say), ment in the mud-crab Rhithropanopeus harrisii. In reared in the laboratory. Chesapeake Sci. 11:16-29. D. J. Crisp (editor), Fourth European Marine Biology PORTER, H. J. Symposium, p. 211-220. Camb. Univ. Press, Lond. I960. Zoeal stages of the stone crab, Menippe mercenaria Say. Chesapeake Sci. 1:168-177. COSTLOW, J. D„ JR., C. G. BOOKHOUT, AND R. MONROE. RATHBUN, M. J. 1962. Salinity-temperature effects on the larval develop- 1930. The Cancroid crabs of America of the families ment of the crab, Panopeus herbstii Milne-Edwards, Euryalidae, Portunidae, Atelecyclidae, Cancridae and reared in the laboratory. Physiol. Zool. 35:79-93. Xanthidae. U.S. Natl. Mus. Bull. 152, 609 p. GORE, R. H., C. L. VAN DOVER, AND K. A. WILSON. SABA, M., M. TAKEDA, AND Y. NAKASONE. 1981. Studies on decapod Crustacea from the Indian 1978. Larval development of Epixan/hus dentatus (White) River region of Florida. XX. Micropanope barbadensis (Brachyura, Xanthidae). Bull. Natl. Sci. Mus. (Tokyo), (Rathbun, 1921): the complete larval development under Ser. A (Zool.) 4:151-161. laboratory conditions (Brachyura, Xanthidae). J. SANDIFER, P. A. Biol. 1:28-50. 1974. Larval stages of the crab, Pilumnus dasypodus GUINOT, D. Kingsley (Crustacea, Brachyura, Xanthidae), obtained in 1967. Recherches preliminaires sur les groupements the laboratory. Bull. Mar. Sci. 24:378-391. naturels chez les crestaces decapodes brachyoures. II. SCOTTO, L. E. Les anciens genres Micropanope Stimpson et Medaeus 1979. Larval development of the Cuban stone crab, Dana. Bull. Mus. Natl. Hist. Nat., 2e Sev. 39.345-374. Menippe nodifrons (Brachyura, Xanthidae), under HYMAN, O. W. laboratory conditions with notes on the status of the 1925. Studies on the larvae of crabs of the family Xan- family . Fish. Bull., U.S. 77:359-386. thidae. Proc. U.S. Natl. Mus. 67(2575), 22 p. WEAR, R. G. LEBOUR, M. V. 1968. Life-history studies on New Zealand Brachyura. 2. 1928. The larval stages of the Plymouth Brachyura. Family Xanthidae. Larvae of Heterozius rotundifrons Proc. Zool. Soc. Lond. 1928:473-560. A. Milne-Edwards, 1867, Ozius iruncatus H. Milne- MCDONALD, H. J., AND W. LANG. Edwards, 1834, and Heteropanope (Pilumnopeus) 1976. The larval development of Pilumnus sayi Rathbun serratifrons (Kinahan, 1856). N. Z, J. Mar. Fresh- reared in the laboratory. Am. Zool, 16:219. water Res. 2:293-332. MCMAHAN, M. R. 1970. Notes and bibliography on the larvae of xanthid 1967. The larval development of Neopanope texana texana crabs. Pac. Sci. 24:84-89. (Stimpson) (Xanthidae). Fla. Board Conserv. Mar. Res. YANG, W. T Lab. Leafi. Ser. 2, 16 p. 1967. A study of zoeal, megalopal, and early crab stages ONO, K.-S., AND J. D. COSTLOW, JR. of some oxyrhynchous crabs (Crustacea: Decapoda). 1970. The effect of salinity and temperature on the larval Ph.D. Thesis, Univ. Miami, Coral Gables, Fla., 459 p.

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