Abstract. -Developmental stagesof pygmy poacher, Odontopyxistrispinosa. and blacktip poacher,Xeneretmus latifrons, are describedand illustrated from specimens col­lected from the northeastern PacificOcean. External morphology, pig­mentation, and meristic features aredescribed which distinguish larvaeof these species from other agonidsoccurring in these waters.

Postanal pigment patterns, par­ticularly on the caudal finfold, dis­tinguish preflexion larvae. Odon­topyxis trispinosa larvae possess asemicircular patch of melanophoresthat covers nearly the entire caudalfinfold. The caudal finfold of pre­flexion X latifrons larvae are voidof pigment with the exception of asmall patch of melanophores nearthe ventral margin of the notochordtip. Flexion and postflexion larvaecan be distinguished by caudal andanal fin pigmentation, head spina­tion, and adult meristic features.

Development of larval and earlyjuvenile pygmy poachetOdontopyxis trispinosa, andblacktip poachet Xeneretmuslatifrons (Scorpaeniformes:AgonidaeJ

Morgan S. BusbyResource Assessment and Conservation Engineering DivisionAlaska Fisheries Science CenterNational Marine Fisheries Service. NOAA7600 Sand Point Way NE. Seattle. Washington 98 J J5-0070

David A. AmbroseSouthwest Fisheries Science CenterNational Marine Fisheries Service. NOAAPO. Box 27 I. La Jolla. California 92038

Manuscript accepted 26 February 1993.Fishery Bulletin. 91:397-413 (1993).

The family Agonidae is a morphologi­cally diverse group of relatively small.benthic marine fishes. Agonids, com­monly called poachers. are character­ized by the presence of fused or over­lapping bony plates that encase thebody. Fifteen genera represented by25 species occur in the northeasternPacific (Matarese et aI.. 1989).

The pygmy poacher Odontopyxistrispinosa is a small (to 8.1cm SL)subtidal agonid distinguished by anelongate body, small vertical spine atthe snout tip, and a moderately de­veloped occipital pit divided by a lon­gitudinal ridge. Fin-element countsof O. trispinosa are Dill-VI, 5-7; A5-7; P 13-15; V 1,2 (Matarese et al.,1989). The blacktip poacher Xener­etmus latifrons is a larger (to 19 cmSL) subtidal agonid distinguished byblack margins on the dorsal fins anda weakly developed occipital depres­sion (Miller and Lea, 1972; Hart.19731. Fin-element counts of X.latifrons are D VI-VIII, 6-8; A 6-9;P 13-15; V 1.2 (Matarese et al., 19891.The presence of spiny scales on theeyeballs distinguishes X. latifronsfrom X. leiops. The absence of

cheekplates distinguishes X. latifronsfrom X. triacanthus (Miller and Lea,1972; Eschmeyer et al., 1983).

Freeman (1951) hypothesized thatthese two taxa are closely relatedphylogenetically and placed them inhis subfamily Xeneretminae. The cla­distic analysis of Kanayama (1991)demonstrated close relationships be­tween the two taxa which he placedin the subfamily Anoplagoninae.

The geographic range of adultO. trispinosa extends from SoutheastAlaska to central Baja California.Adult X. latifrons occur over aslightly narrower range from Van­couver Island to northern Baja Cali­fornia (Eschmeyer et aI., 1983). Bothtaxa occur at depths of 18-370 m(Miller and Lea, 1972; Hart. 1973).Larval O. trispinosa and X. latifronsare the most commonly occurringagonids in the California CooperativeOceanic Fisheries Investigations(CaICOFIl ichthyoplankton collection l .

I Moser, H. G., ed. Guide to the early stages offishes from the California Current region. South­west Fisheries Science Center, NMFS, P.O. Box271, La Jolla. CA 92038. In preparation.

397

398 Fishery Bulletin 91 (3). 1993

28'

30'

32'

34'

36°

38°

• 26'

115'119'127'

juveniles of both taxa were collected with dipnets, 60­and 70-cm bongo nets, Isaacs-Kidd midwater trawls.

& Xeneretlllus llltifroDS

• Odontopyxis trispinos"

131' 123'

Figure 1Collection locations of Odontopyxis trispinosa and Xeneretmlls latifrons larvae and earlyjuveniles used in this study.

135' oo'W

Specimens

Agonid larvae examined in thisstudy were obtained from collec-tions made off the coasts of BajaCalifornia, California, Oregon,Washington (including PugetSound), Southeast Alaska, andthe inside passage waters of Brit­ish Columbia, Canada (Fig. 1).One hundred and thirty-six O.trispinosa (4.3-56.0mm SL) and77 X. latifrons (4.8-79.0mm SLIwere examined. The largestspecimens of each taxa were determined to be adultsand are not included in the descriptions. Larvae and

Methods

Larval development of agonidsis poorly known. Washington etal. (1984) and Maeda andAmaoka (1988) reported that for­mation of most external bodyparts, including dermal bonyplates and spines, begins earlyin larval development.

Development of the pygmypoacher (0. trispinosa) is de­scribed for the first time here.Development of X. latifrons isclarified based on new material.A partial developmental series (7,10, 16 mm SL) ofX. latifrons waspreviously described by Marliave(1975). Washington et al. (1984)included a single illustration ofX. latifrons (9.6 mm SL) whichdiffered markedly in appearancefrom those in Marliave (1975>­Matarese et al. (1989) combinedthe illustrations from bothsources to create a complete de­velopmental series. As a result,some confusion exists as to whichillustrations in this series are ac­tually those of X. latifrons lar­vae. The following descriptionsare the first complete accountsof larval development in thefamily Agonidae. Characters arepresented that permit identifica­tion of these larvae from fieldcollections.

Busby and Ambrose: Development of larval and juvenile Odontopyxis trispinosa and Xemeretmus latifrons 399

Tucker trawls, sled trawls, and bottom trawls. Collec­tions were made by the Vancouver Public Aquarium(VPAI. Oregon State University (osm. University ofWashington (UWI, NOAA's Southwest Fisheries Sci­ence Center (SWFSC-CaICOFI program), and theAlaska Fisheries Science Center (AFSC) from the years1932 to 1991. Specimens are currently housed in thelarval fish collections of these institutions. Larvae andjuveniles were originally fixed in 3.5 or 5.0% formalinand subsequently transferred and stored in 3.5% buff­ered formalin or 70% ethanol.

Larvae of O. trispinosa and X latifrons were identi­fied using the serial approach. This method uses adultcharacters to progressively link juveniles to smallerspecimens through a continuous sequence ofshared simi­larities. Pigmentation. head spination, body morphol­ogy, dermal plates, and meristic features were all usedas diagnostic characters. Identification of adult and ju­venile specimens was accomplished by using methodsof Miller and Lea (1972), Hart (1973). and Kanayama(1991). Nomenclature and taxonomic classification ofthe family Agonidae follow Kanayama (1991), Develop­mental series were illustrated by using a camera lucidaattached to a dissecting stereomicroscope.

Only melanistic pigmentation is described becauseformalin fails to preserve color pigments. In the de­scription of pigmentation. the term "band" refers toany aggregation of melanophores that approximates avertically oriented rectangle. A"bar" also approximatesa rectangle but is horizontally oriented. A "patch" isany other distinguishable aggregation of melanophores.

Measurements

The following measurements were made on 45 larvaeand early juveniles of O. trispinosa and 45 larvae ofX latifrons by using an ocular micrometer in a stereo­microscope:

Standard length (SL)-Snout tip to notochord tipprior to development of caudal fin, then to posteriormargin of hypural element. (All body lengths in thisstudy are standard lengths. I

Body depth-Vertical distance from dorsal to ventralbody margin at pectoral-fin base.

Snout to anus length-Distance along body midlinefrom snout tip to a vertical line through center ofanal opening.

Head length (HL)-Snout tip to posterior edge ofopercle (to pectoral-fin base in small larvae beforeopercular margin is visible).

Head width-Distance across head between dorsalmargins of orbits.

Snout length-Snout tip to anterior margin of orbitofleft eye.

Eye diameter-Greatest diameter of left orbit.Pectoral fin length-Distance from pectoral-fin base

to tip of the longest ray.

Osteology

Selected specimens were cleared and differentiallystained to identify cartilage and bone with alcianblue and alizarin red-S (Pothoff, 1984). Skeletal ele­ments and dermal plates were recognized as ossifiedupon initial uptake of alizarin red-So Twenty-sevenO. trispinosa (5.3-41mm) and 12 X latifrons (7.4­39.2 mm) were cleared and stained for study. Countsof meristic features were made on stained specimensonly. Not all stages of development were stained forX latifrons because specimens were limited. Preflexion,flexion, and postflexion stage larvae were stained(Kendall et aI., 1984). Nomenclature of skeletal ele­ments follows that used by Leipertz (1985) for X.triacanthus. Plate nomenclature follows that of Gruchy(1969) and is described in Figure 2. Terminology oflarval head spination follows that proposed for adult

-- ... - -.. ' .. ' .:. ..'

Figure 2Terminology of bony plates in agonid larvae: DLP=dorsolateral; MDP=mid-dorsal; SLP=supralateral; LLP=lateralline; ILP=infralateral;VLP=ventrolateral; MVP=mid-ventral (after Gruchy, 19691.

400

agonids by Laroche (1986), For larvae with spines andno named analogous adult spine, terminology followsMoser and Ahlstrom (1978) or Richardson and Laroche(19791 for larvae of rockfish Sebastes spp. (anotherScorpaeniforml (Table 1, Figs. 3 and 41.

Results

Development of Odontopyxis trispinoa

Morphology Larvae of O. trispinosa are elongate andslender with mean body depth at the pectoral fin ori­gin of 11.7% 8L in preflexion specimens decreasing to10.7% 8L in flexion and postflexion larvae (Tables 2and 3). Mean head length is 18.4% 8L in preflexionlarvae and increases to 23.8% 8L in juveniles (Table31. Mean head width is approximately 50.0% HLthroughout larval development and decreases to 37.1%HL in juveniles tTable 3). Mean snout length increasesfrom 20.4% HL in preflexion larvae to 27.0% HL inpostflexion larvae and eye diameter decreases from33.3% HL in preflexion larvae to 23.3% HL in juve­niles. Mean pectoral-fin length increases from 7.0% 8Lin preflexion larvae to 19.5% 8L in postflexion larvaetTable 3). The gut is moderately long: mean snout toanus distance is 47.9% 8L in preflexion larvae anddecreases to 33.0% 8L in juveniles.

Fishery Bulletin 9 J (3). J993

Pigmentation Pigmentation in O. trispinosa larvaewas relatively consistent among specimens and is auseful distinguishing character (Fig. 5),

Head region Pigmentation on the head of preflexionlarvae is present as rows of melanophores on the up­per and lower jaws. A few additional melanophoresare present on the snout. Melanophores on the opercu­lar and hyoid regions join the upper and lower jawpigmentation to form a continuous swath giving lar­vae a "bearded" appearance (Fig. 5Al. In flexion lar­vae, additional melanophores appear posterior to theeye.

Lateral body and gut region The dorsolateral sur­face of the body above the gut is covered with melano­phores with the exception of a patch along the dorsalmidline above the pectoral fin. The dorsolateral pig­mentation recedes ventrolaterally toward the gut withdevelopment and is completely absent in postflexionlarvae. Melanophores cover nearly the entire caudalportion of the body in preflexion larvae. In some speci­mens, the notochord tip is unpigmented. In late flexionand postflexion larvae, pigmentation on the lateral bodysurface begins to separate gradually into seven bands(Fig. 5D). The first band extends from the posteriorregion of the first dorsal fin to the ventral body mid­line immediately posterior to the anus. The secondband extends between the first two soft rays of the

Table 1Head spine terminology in agonid larvae listed by sequence of development in Odontopyxis trispinosa. lPI designates dermalplate.

Abbreviation

PASPOSCCOPTNAAPO-4PPO-l,2PPO-3.4SIO-5.6CLTMOPFRSOPS10-l,2PSO-lPSO-2.3ROPST110-1,2SIO-3.4110-3SCL

SpinelPlate name

ParietalSupraocularSupracleithralCoronalPteroticNasal4th Anterior Preopercular1st. 2nd Posterior Preopercular3rd, 4th Posterior Preopercular5th, 6th Superior InfraorbitalCleithralTympanicOpercularFrontalSubopercular1st. 2nd Superior Infraorbital1st Postocular2nd, 3rd Postocular (p)

RostralPosttemporal (p)1st. 2nd Inferior Infraorbital (PI3rd, 4th Superior Infraorbital3rd Inferior InfraorbitallP)Sclerotics (PI

Bone of origin

ParietalFrontalSupracleithrumFrontalPteroticNasalPreoperclePreoperclePreopercleInfraorbital 3CleithrumFrontalOpercleFrontalSubopercleInfraorbitalllLachrymal1FrontallDermallRostral PlatelDermal)lDermal1Infraorbital 2 (Jugal)lDermal)Sclerotic

Adult spine/plate

ParietalSupraocularSupracleithral(Overgrown)PteroticNasal(Overgrown)PreopercularPreopercularPosterior infraorbitalsIOvergrown)I.OvergrownIOpercular(Overgrown IGill Cover SpineAnterior InfraorbitalPostocularPostocular PlatesRostral(Overgrown I

Anterior, Medial Cheek PlatesMedial InfraorbitalPosterior Cheek PlateEyeball Plates

Busby and Ambrose: Development of laNai and juvenile Odomopy<is trispinosa and Xemeretmus latifrons

PA PST

sc 14-lH---FR

401

Figure 3Positions and abbreviations of larval head spines and platesin agonids. Based on a 17.2-mm stained larva of Odontopyxistrispinosa (modified from Moser and Ahlstrom (1978),Richardson and Laroche (1979), and Laroche (1986)).

dorsal and anal fins and is connected ventrally to thefirst band by a bar. The third band extends from theposterior half of the second dorsal fin to the posteriorhalf of the anal fin. The remaining four bands areevenly spaced on the body between the posterior edgesof the second dorsal and anal fins and the caudal fin.The third, fifth, and seventh bands are the widest.The posteriormost band of pigmentation in postflexionlarvae and early juveniles is located at the hypuralmargin and is continuous with the caudal-fin pigment.

The entire ventral and lateral surfaces of the gut inpreflexion larvae are covered with pigmentation. Adense row of melanophores is present along the ven­tral midline from the isthmus to the end of the pre­anal finfold. The ventral midline pigmentation can bedistinguished easily in lateral view through thepostflexion stage. In some specimens, a small. circular.unpigmented area is present on the lateral surface ofthe gut posterior to the pectoral-fin rays.

Fins The base of the pectoral fin is completely cov­ered with melanophores throughout development. Pig­mentation is absent from the pectoral-fin blade, rays,and membrane.

Figure 4Thp view above eye showing superior infraorbital and frontalspines of a 17.2-mm SL, cleared and stained Odontopyxistrispinosa.

Most preflexion and flexion specimens possess asmall group of melanophores on the anterior portion ofthe dorsal finfold near the body margin over the gut(Fig. 5A). This patch migrates posteriorly with devel­opment and becomes the pigmentation seen on thefirst dorsal fin in postflexion larvae and juveniles(Fig. 5, C and D). A larger patch of melanophores ispresent at approximately midbody which usually ex­tends to the dorsal edge of the finfold in preflexionlarvae. This dorsal midbody patch recedes toward thebody and splits into two somewhat triangular-shapedpatches of pigmentation in flexion larvae. This largerpatch of pigmentation is retained on the second dorsalfin in postflexion larvae and juveniles. The finfoldpatches roughly correspond to body bands on postfl.exionand juvenile specimens. Three additional triangular­shaped patches of melanophores are present approxi­mately two-thirds of the distance between the anusand notochord tip on the dorsal finfold and form acontinuous region of pigment extending to the caudalfinfold. The triangular-shaped patches of pigmentationseparate in flexion larvae and disappear as the finfoldrecedes in postflexion larvae.

402 Fishery Bulletin 91 (3). 1993

Table 2Morphometric measurements (in millimetersl of 45 Odontop.vxis trispinosa larvae andearly juveniles. Specimens between dashed lines (- -) were undergoing notochord flexion.

Standard Bodvlength depth

4.34.54.65.25.35.35.96.46.76.86.87.2

7.17.98.59.19.810.010.811.7

11.811.812.512.612.712.813.713.813.914.314.714.815.015.215.415.816.717.517.717.728.032.134.836.441.6

0.440.600.600.620.600.640.620.740.700.760.820.86

0.880.660.920.961.001.061.201.36

1.421.441.221.321.261.301.641.581.381.501.321.521.601.701.661.621.701.872.201.762.753.333.423.924.83

Snont toanus length

2.022.062.242.482.522.602.723.243.243.203.123.48

3.603.404.124.124.604.405.005.25

5.505.425.675.835.425.836.336.086.086.175.876.085.835.926.176.636.506.847.587.009.58

10.5011.3011.7014.50

Headlength

0.780.720.801.020.961.021.041.141.201.261.401.36

1.381.341.761.502.061.702.362.52

2.262.802.702.802.762.702.922.923.003.253.003.003.603.843.203.504.244.264.324.487.407.588.088.259.67

Headwidth

0.400.520.440.480.460.460.420.440.560.560.620.70

0.700.660.800.660.921.251.081.20

1.241.241.201.441.281.201.501.301.461.501.401.401.541.801.601.822.041.981.862.002.882.883.122.923.33

Snoutlength

0.140.120.180.220.200.180.200.260.220.300.300.30

0.300.320.500.380.600.410.520.60

0.740.760.740.860.760.680.900.800.740.800.720.760.901.000.840.911.121.131.241.201.561.841.922.172.50

Eyediameter

0.280.300.300.320.320.360.340.360.400.400.360.40

0.400.360.440.420.520.450.600.58

0.560.600.600.700.640.600.720.660.700.740.760.660.840.840.720.860.980.900.841.061.641.752.001.922.25

Pectoralfin length

0.300.300.340.340.440.360.380.340.460.500.500.52

0.500.600.701.001.401.051.461.64

2.462.262.082.482.422.422.242.352.802.962.642.683.203.203.203.163.683.083.723.684.685.586.006.336.92

A small patch of melano­phores is present on the analfinfold immediately posterior tothe anus. This small patch ofpigmentation is a useful char­acter which persists untilpostflexion when it migrates dor­sally with the receding finfoldto form the bar between the firstand second body bands (Fig. 5m.A large triangular-shaped patchof pigment is present at midbodyand extends nearly to the finfoldmargin in preflexion and earlyflexion larvae. The large trian­gular-shaped patch expands ven­trally to the finfold margin andbecomes more rectangularshaped in late flexion larvae.This is the only pigmentationpresent on the anal fin inpostflexion larvae and juveniles(Fig. 5, C and DJ. Two additionalpatches of melanophores arepresent on the anal finfold inpreflexion larvae. These form anearly continuous region of pig­mentation which begins at ap­proximately two-thirds of thedistance between the anus andnotochord tip which extends tothe caudal finfold. This pigmen­tation breaks apart in lateflexion larvae and disappears asthe finfold recedes in postflexionlarvae.

The posteriormost dorsal andanal finfold pigmentation con­nect and are continuous with alarge semicircular patch of mel­anophores which covers nearly

Table 3Body proportions of Odontop.vxis trispinosa larvae and early juveniles. Values given for each body proportion areexpressed as percentage of standard length (SLl or head length (HL): mean, standard deviation, and range.

Body proportion Preflexion Flexion Postflexion Juvenile

Sample size 12Standard length 5.7±1.0 (4.3-7.2)Body depth/SL 11.7±1.0 (10.2-13.41Snout to anus length/SL 47.9±1.4 (45.7-50.31Head length/SL 18.4±1.2 1I6.1-20.5)Head widthlHL 48.7±8.7 (40.4-72.2)Snout lengthIHL 20.4±2.3 1I6.7-23.8)Eye diameterlHL 33.3±4.0 (25.7-41.7)Pectoral fin length/SL 7.0±O.7 (5.3--8.4)

89.4±1.5 (7.1-11.7)

10.7±1.2 (8.4-12.4)46.2±2.5 (43.2-50.8)19.4±2.2 (16.5-21.8150.1±9.7 (44.0-73.5)24.8±2.7 (21.7-29.1126.1±1.9 (23.0--29.0)1O.8±2.9 (7.1-14.21

2014.5±1.9 m.8--17.7110.7±O.9 (9.0-12.4)42.5±2.8 138.9-46.6122.4±1.9 1I9.2-25.4147.2±3.3 (43.1-54.9)27.0±2.3 (24.0--32.7123.0±1.5 (19.4-25.3)19.5±1.7 (16.3-21.3)

534.6±5.1 (28.0--41.6110.5±O.7 (9.8-11.6)33.3±1.2 (32.1-34.9)23.8±1.5 (22.7-26.4)37.1±2.0 (34.4-38.9)24.3±2.1 121.1-26.3)23.3±O.9 122.2-24.8117.1±O.4 (16.6--17.4)

Busby and Ambrose: Development of larval and juvenile OdontoPY'<is trispinosa and Xemeretmus latifrons 403

A

B

c

D

7.9mm

14.7 mm

Figure 5Larval stages of Odolltupyxis trispinosa. tAl Preflexion larva 4.3mm SL, CalCOFI 5405-73.50. CB) Early flexion larva 7.9mm SL.CalCOFI 6304-110.32. Ie) Flexion larva 1O.3mm SL, VPA. Lambert Channel 4126191 No.7. (Dl Postflexion larva 14.7mm SL. CalCOFI7412-83.44.

404

the entire caudal finfold. Caudal pigmentation persiststhroughout development.

Osteology Although precursors of some bony struc­tures such as dermal plates and fin rays are discemableas early as 8.0 mm, actual ossification of skeletal ele­ments in O. trispinosa does not begin until approxi­mately 12.0 mm.

Cranium The parasphenoid and basioccipital bonesof the cranium begin to ossify at 11.7mm. At 13.2 mm,several bones, including the nasal, frontal, parietal,parasphenoid, basioccipital, and exoccipital are com­pletely ossified. The rostral plate, nasal, lateral eth­moid, supraethmoid, vomer, exoccipital, lachrymal, andremainder of the circumorbital series ossify by 14.8mm.The sphenotic, prootic, epiotic, tabular, and ptero­sphenoid are ossified by 27.0mm.

Spines Numerous head spines are ossified at12.6 mm including the nasal, supraocular, the largebilobed parietal, coronal, pterotics, supracleithral, an­terior preoperculars and posterior preoperculars 1 and2. The tympanic, cleithral, opercular, fifth and sixthsuperior infraorbital spines, and the third and fourthposterior preopercular spines are also ossified at thisstage. The frontal spine forms by 13.8mm but is notvisible in lateral view because it is small and locatedbehind the anterior margin of the supraocular spine.The frontal spine becomes overgrown with bone and isdifficult to distinguish at 17.2 mm. Interopercular andsuperior infraorbital spines 1 and 2 begin forming atabout 14.2 mm. The rostral and postocular spines andthe postocular and posttemporal plates ossify at14.8 mm. Superior infraorbital spines 3 and 4 and in­ferior infraorbital plates 1 and 2 are completely ossi­fied at this size. The third inferior infraorbital andsclerotic plates are ossified by 17.2 mm. All spinesdescribed here are paired with the exception of therostral.

Mandibular region The dentary, angular, and ar­ticular bones of the lower jaw are the first to ossify inpostflexion larvae of 11.7 mm. At 12.6 mm, the pre­maxilla and maxilla are ossified.

Palatine region Palatine, quadrate, metapterygoid,mesopterygoid. ectopterygoid, and symplectic bones areossified at 12.6 mm.

Opercular region The preopercle. opercle, inter­opercle, and subopercle are ossified by 12.6 mm.

Hyoid region The basihyal, hypohyal, urohyal,ceratohyal, epihyal, interhyal, glossohyal, and bran­chiostegal rays are also ossified by 12.6 mm. Thehyomandibula is ossified by 27.0mm.

Branchial region The pharyngobranchial teeth arethe first structures to ossify by 11.7mm. Ossificationof the pharyngobranchials occurs at about 17.2 mm.The pharyngobranchials begin as four pieces of carti-

Fishery Bulletin 9 J (3). 1993

lage that apparently fuse before ossification of thepharyngobranchial teeth. This process, however, wasnot observed. The epibranchials (n=41 and cerato­branchials (n=51 also ossify hy 17.2mm. The remain­ing branchial support structures, including thehypobranchials (n=3) and basibranchials (n=31, ossifyby 27.0mm.

Appendicular region The cleithrum, postcleithrum,and coracoid are ossified by 12.6 mm. The pelvic-finspine and all pectoral-fin rays, with the exception ofthe ventralmost, ossify by 12.8 mm. The two pelvic-finrays and the final 114th) pectoral-fin ray are ossifiedby 13.2 mm. The supracleithrum ossifies at about13.8mm. At 14.8mm, ossification of the posttemporalis completed. Ossification of the basipterygium occursat 17.2 mm. The scapula and three radials supportingthe pectoral-fin rays are ossified by 27.0 mm.

Median fins All dorsal- and anal-fin spines andsoft rays are ossified by 12.6mm (Table 4). Six supe­rior principal rays and five inferior principal rays inthe caudal fin are ossified at this size (total=l1l. Oneinferior principal (121, and two superior procurrent rays(13, 14) are ossified by 13.2 mm. By 17.2 mm one addi­tional superior (151 procurrent caudal ray is formedwhich completes the adult count <3+6+6+0=15). Ossifi­cation of the epural, hypural plate. and pterygiophoressupporting the dorsal- and anal-fin rays is completedby 27.0mm.

Vertebral column Ossification ofvertebral elementsprogresses from anterior to posterior. Notochord flexionbegins at approximately 7.0mm and is completed by11.8 mm. All, except the posteriormost caudal verte­bral centrum, are ossified by 12.6 mm. The urostyleand the anteriormost neural and haemal spines arealso complete by 12.6 mm. All abdominal neural spinesare complete and three additional haemal spines formanteriorly by 13.2 mm. All vertebral centra are ossifiedby 13.8 mm and two additional haemal spines haveformed. By 14.2 mm, 22 additional haemal spines de­velop. All neural spines are ossified by 14.8 mm andhaemal spines are complete at 15.4mm.

Dermal plates Precursors of the supra (SLP) andinfralateral iILP) plates first appear as small singularspines which are distinguishable at about 8.0 mm. Os­sification, however, does not begin until approximately12.0 mm and progresses from anterior to posterior. Bonedevelops radially from the base of the spine to eventu­ally form the juvenile/adult dermal plate. By 12.6 mm,ossification of the SLP and ILP series is complete. Thedorsolateral and mid-dorsal (DLP+MDP) and the ven­trolateral and mid-ventral (VLP+MVPI plate series arecomplete by 14.8mm. The lateral line (LLP) plate se­ries begins to form at about 14.0 mm. Lateral line platesare the only plates that begin development as bifur­cate spines. Ossification of the LLP series is complete

Table 4MeriBtics of cleared and stained Odontopyxis trispinosa larvae and early juveniles. Specimens between dashed lines (--) were undergoing notochord flexion.

11.712.512.6 5 6 6 13 6 3 3 13 25 38 30 35 35 3213.1 3 6 2 213.2 5 6 6 14 1.2 6 13 20 33 3 13 27 40 32 38 2 36 3413.8 3 6 2 213.8 4 6 7 13 1,2 6 13 22 35 6 13 27 40 34 38 36 3714.2 5 7 6 14 1,2 6 13 19 32 5 13 26 39 34 36 1 35 3414.8 5 7 6 14 1,2 6 13 25 38 29 13 26 39 36 38 38 37 3615.2 5 6 6 13 1,2 6 13 25 38 23 13 26 39 37 39 33 37 3715.2 4 4 6 14 1,2 6 13 25 38 26 13 26 39 37 37 1 35 3615.4 4 6 7 14 1,2 6 13 24 37 31 13 25 38 36 37 23 36 3716.7 5 f' 6 14 1,2 6 13 25 38 31 13 26 39 37 37 20 35 3717.2 6 6 7 14 1,2 6 13 25 38 31 13 26 39 37 38 38 36 3727.0 4 6 5 14 1,2 6 13 25 38 32 13 26 39 36 37 39 36 3629.0 5 6 6 14 1,2 6 13 24 37 31 13 25 38 37 39 38 36 3741.0 4 6 6 13 1,2 6 13 24 37 31 13 25 38 36 38 39 36 36

Body plates*

total DLP+MDP SLP LLP 1LP VLP+MVP

CentraHaemalspines abdominal caudaltotal

Pelvic fin Branchi- Neural spinesspines, ostegal

rays rays abdominal caudal----- Anal fin Pectoral

rays fin rays

Standard Dorsal finlength(mm) spines rays

5.35.86.1

7.07.78.38.59.310.011.4

*DLP=dorsolateral: MDP=mid-dorsal; SLP=supralateral: LLP=lateralline; 1LP=infralateral; VLP=ventrolateral; MVP=mid-ventral.

-l>oolJl

406 Fishery Bulletin 91 (3). 1993

Table 5Morphometric measurements (in millimeters) of 45 Xeneretmus latifrons larvae. Speci­mens between dashed lines (- -) were undergoing notochord flexion.

Standard Body Snout to Headlength depth anus length length

Snout Eye Pectorallength diameter fin length

by 17.2 mm. Breast plates on theventral surface of the abdomenand pelvic region are completeby 12.6 mm. The number of pec­toral-fin base plates in O.trispinosa is variable rangingfrom 3 to 8 among specimens ex­amined. Ossification of pectoral­fin base plates is complete byabout 13.8 mm.

Development ofXeneretmus latifrons

Morphology Larvae of X.latifrons are deeper bodied thanO. trispinosa; mean body depthat the pectoral-fin origin rangesfrom 13.3% 8L in preflexionspecimens to 14.6% 8L post­flexion (Tables 5 and 6; Fig. 6).Head length increases from20.3% 8L in preflexion larvae to26.6% 8L in postflexion larvae,and snout length as a propor­tion of head length increasesfrom 18.8% HL in preflexion lar­vae to 24.4% HL in postflexionlarvae (Table 6). Eye diameterdecreases from about 37.5% HLin preflexion larvae to 28.4% HLin postflexion larvae, and headwidth remains approximately54-55% HL throughout develop­ment (Table 6).

Pectoral-fin length increasesfrom 8.4% 8L in preflexion lar­vae to 21.8% 8L in postftexionlarvae. In preflexion larvae,snout to anus distance is 51.7%

4.95.15.15.35.55.66.06.06.86.87.07.27.87.98.3

~.l:.I

9.39.89.910.010.010.510.8

10.811.411.811.812.512.712.713.213.914.214.714.715.516.616.818.322.030.030.531.839.242.0

0.720.660.700.660.760.680.780.720.820.801.100.881.160.961.30

1.141.301.181.601.201.481.501.72

1.721.681.881.641.961.971.962.062.302.102.222.082.582.742.522.583.043.674.003.924.335.12

2.202.562.482.402.882.922.922.983.403.363.804.044.804.124.78

4:7~

5.675.335.506.085.6;5.756.17

6.256.506.506.086.677.006.676.707.087.127.587.337.148.067.928.069.40

11.5011.3011.8012.7014.20

0.840.961.060.901.261.001.141.151.321.201.661.802.081.541.54

UJ42.682.442.562.442.362.962.68

2.802.882.882.883.283.443.363.523.924.043.843.563.804.864.604.865.178.678.679.58

10.7011.20

Headwidth

0.480.500.540.440.660.500.640.600.660.660.801.001.080.841.13

1.U41.521.241.441.361.301.641.42

1.801.861.701.901.941.882.062.002.302.102.122.102.582.302.402.743.043.604.334.424.755.42

0.060.160.200.160.260.200.230.220.240.200.280.420.560.300.32

U.440.500.560.640.600.540.620.62

0.640.720.740.700.780.940.660.900.981.100.940.780.911.061.161.371.672.251.922.002.332.50

0.380.380.380.380.400.400.440.400.460.420.460.520.640.480.61

U.O:.!0.820.680.740.740.700.860.80

0.880.880.780.761.020.860.960.921.021.081.020.961.091.221.261.221.522.252.923.083.423.67

0.340.340.380.320.440.400.500.400.420.500.521.081.140.620.81

U.~~

1.801.501.801.621.422.482.14

2.322.302.203.002.642.803.003.123.523.723.523.763.734.403.844.104.415.335.505.586.837.08

Table 6Body proportions of Xeneretmus latifrons larvae. Values given for each body proportion areexpressed as percentage of standard length (SL) or head length <HLJ: mean, standard deviation.and range.

Body proportion Preflexion Flexion Postflexion

Sample size 15Standard length 6.3±1.1 (4.9-8.3)Body depth/SL 13.3±1.4 1ll.9--15.7)Snout to anus length/SL 51.7±4.5 (44.7--61.9)Head length/SL 20.3±3.0 117.1-26.8)Head widthIHL 53.9±6.0 (48.2-73.4)Snout lengthlHL 18.8±4.2 (7.1-26.9)Eye diameterlHL 37.5±5.1 (27.7-45.2)Pectoral fin length/SL 8.4±2.8 (6.1-15.1)

89.9±O.6 (8.9--10.8)

14.2±1.6 112.1-15.9)56.7±2.7 (53.6--60.8)25.3±2.3 (21.7-28.7)54.8±2.0 150.8-56.7)22.6±2.0 118.7-25.0)29.8±1.2 (27.9-32.0117.1±4.1 (9.9--23.6)

2219.0±9.4 (10.8-42.0l14.6±1.6 111.0-16.6)47.4±7.6 (32.4-57.9)26.6±1.8 (23.5-30.1)55.6±7.2 (41.5--67.9124.4±2.8 119.6-32.3)28.4±2.8 (25.0-33.7)21.8±3.1 116.9-26.5)

Busby and Ambrose: Development of larval and juvenile Odontopyxis trispinosa and Xemeretmus latifrons 407

• Odonropyxis Irispinosa

.. Xenerelmus lalifrons

•••

.... ..

•

..

\ .-.. .••

•

..

•. ..,A .........

.. ....

.& ..... •

••

.... ..

..

....

.. ..

..

.....~ .. t.!• ,.A. •

•

+---------1If--------j-------j--------f----------j

5 10 15 20 25

3.50

3.00

2.50

E.§. 2.00.ca•0 1.50 ->-"a0III

1.00

0.50

0.00

0

Standard Length (mm)

Figure 6Plot of body depth vs. standard length (mml for larval Odontopyxis trispinosa and Xeneretmus latifrons.

SL, increases to 56.7% SL during flexion, and decreasesto 47.4% SL during postflexion.

Pigmentation Pigmentation in X. latifrons is consis­tent among specimens and is a useful distinguishingcharacter (Fig. 7J. Because pigmentation on the headand gut regions of X. latifrons is so similar to thatdescribed previously for O. trispinosa, discussion herewill be limited to areas of the lateral body and finsthat are diagnostically important.

Lateral body The lateral surface of the body abovethe gut in preflexion larvae is covered with melano­phores, with the exception of an elongate, unpigmentedarea along the dorsal midline above the pectoral fin.Melanophores cover nearly the entire caudal region ofthe body, with the exception of the notochord tip. Mel­anophores extend along the dorsal and ventral mar­gins of the unpigmented area around the notochordtip (Fig. 7A). By early flexion, melanophores completelycover the notochord tip (Fig. 7BJ.

Three patches of melanophores appear along the dor­sal midline near the notochord tip by about 10.5 mmSL (Fig. 7C l. The anterior patch forms the first bandwhich extends from the dorsal margin of the body,posterior to the pectoral-fin base, to the anterior lat­eral gut area. The second band extends dorsally toconnect with pigmentation seen on the first dorsal fin.The third band transverses the body between theposteriormost dorsal spine and the gut. Four or five

distinct bands of pigmentation form between the ante­rior edges of the second dorsal and anal fins and thecaudal fin. The first two bands transverse the bodybetween the anterior and posterior margins of the sec­ond dorsal and anal fins. One or two bands are presentbetween the posteriormost dorsal- and anal-fin raysand the hypural margin. The last band is the widestand covers the hypural region, extending into the cau­dal fin approximately 15-20% of its length (Fig. 7, Cand Dl.

Fins Melanophores begin to appear on the ventralmargin of pectoral-fin base at about 5.0 mm. The pec­toral-fin base is completely covered with pigment by6.0 mm. Pigmentation is always absent fromthe pectoral-fin blade, rays, and membrane (Fig. 7, Aand B).

A small patch of melanophores appears in the dor­sal finfold above the constriction of the gut at about6.0mm (Fig. 7B). This pigmentation later expands andis that seen on the spinous (first) dorsal fin in lateflexion and postflexion larvae (Fig. 7, C and DJ. Poste­riorly, an additional patch of pigmentation begins aboutone-third of the distance between the anus and noto­chord tip and exhibits an irregular edge, appearingsomewhat serrated, below the dorsal margin.

In preflexion larvae, a large patch of melanophorescovers most of the anal finfold beginning at approxi­mately one-fourth of the distance between the anus andnotochord tip and continuing its entire length. The rela-

408

A

B

c

D

Fishery Bulletin 91 (3). 1993

5.2mm

18.3 mm

Figure 7Larval stages ofXeneretmus latifrons. IA) Preflexion larva 5.2 mm SL, CalCOFI 6501BD-83.43. (8) Early flexion larva 8.7 mm SL, VPA.Lambert Channel 4/22190 No.5. (C) Flexion larva 1O.8mm SL, CalCOFI 5403CR-83.48. tn, Postflexion larva 18.3mm SL, VPA, LambertChannel 5/3188 No.4.

Busby and Ambrose: Development of larval and juvenile Odontopyxis trispinosa and Xemeretmus latifrons 409

tively large unpigmented area anterior of this patch isan important diagnostic feature (Fig. 7, Aand B>.

Both the dorsal and ventral finfold melanophorepatches are constricted nearly to the body margins ata point about 80%-90% of the distance between theanus and notochord tip (Fig. 7B). As notochord flexionprogresses, the ventral patch of pigmentation poste­rior to the constriction on the anal finfold is seen asthe post-hypural pigment present on the caudal fin ofpostflexion specimens (8.7-22.0mm){Fig. 7C). This cau­dal-fin pigmentation extends posteriorly to about 15­20% of the caudal-fin length (Fig. 7, C and D).

The remaining melanophores on the dorsal and analfinfolds migrate toward the body margins as the finfoldrecedes. Discrete melanophore patches remain on theanterior and posterior margins of the second dorsaland anal fins in postflexion larvae (Fig. 7Dl.

Osteology Although precursors of some bony struc­tures such as dermal plates and fin rays are discemableas early as 8.0 mm, ossification in X. latifrons does notbegin until approximately 13.0 mm. The sequence ofossification of bony structures in X. latifrons is nearlyidentical to that described previously for O. trispinosa.The most important difference to note is that ossifica­tion in X. latifrons begins later (13.0 mm), progressesmore rapidly for lateral body plates, and is slower formost skeletal elements than O. trispinosa. The intenthere is to highlight important differences between thetwo taxa.

Cranium All parts of the cranium, with the excep­tion of the sphenotic, prootic, epiotic, tabular, andpterosphenoid are ossified at 13.8mm. These remain­ing cranial elements ossify at about 30.5 mm.

Mandibular region Ossification of all mandibularstructures is complete at 13.8 mm.

Spines Head spination is generally reduced in X.latifrons larvae. Xeneretmus latifrons larvae have noinferior infraorbital, postocular, or posttemporal platesand have only four superior infraorbital spines.The rostral spine, which is weaker than that of O.trispinosa, and sclerotic plates do not develop untilthe late postflexion stage (about 25-30 mm). The tym­panic and frontal spines are more pronounced in X.latifrons larvae than in O. trispinosa.

Palatine region The palatine, quadrate, meta­pterygoid, mesopterygoid, ectopterygoid, and symplecticare ossified at 13.8 mm.

Opercular region The preopercle, opercle, sub­opercle, and interopercle are ossified by 13.8 mm.

Hyoid region The basihyal, hypohyal, urohyal,ceratohyal, epihyal, interhyal, glossohyal, and bran­chiostegal rays are ossified by 13.8 mm. The hyo­mandibula is ossified at 30.5 mm.

Branchial region The pharyngobranchial teeth,pharyngobranchials (n=4, fused as in O. trispinosa),

ceratobranchials (n=5), and epibranchials (n=4) ossifyat about 21.0mm. The remainder of the branchial ap­paratus including the basibranchials (n=3) andhypobranchials (n=3), are ossified by 30.5 mm.

Appendicular region The cleithrum, postcleithrum,supracleithrum, and coracoid are ossified by 13.8 mm.Pelvic-fin spines and rays and all pectoral-fin rays arecomplete at 13.8mm (Table 7). The basipterygium andposttemporal ossify by 21.0mm. The scapula and threeradials supporting the pectoral fin are ossified by30.5mm.

Median fins All dorsal-, anal-, and caudal-fin spinesand soft rays are ossified by 13.8 mm (Table 71. Thecaudal fin has 6 superior principal, 2 superior pro­current, 6 inferior principal, and 1 inferior procurrentrays (2+6+6+1=15 total). Ossification of the hypuralplate and the pterygiophores supporting the dorsal­and anal-fin rays was not complete in the largest speci­men examined (39.2 mm).

Vertebral column Notochord flexion begins at ap­proximately 8.5 mm and is completed by 11.0 mm. Allvertebral centra and the urostyle are ossified by13.8 mm. All except the two posteriormost neural andthree haemal spines are also ossified at 13.8 mm. Ossi­fication of all neural and haemal spines is complete by14.5 mm (Table 7).

Dermal plates All dermal plates are ossified by13.8 mm. Sequence and direction of formation and os­sification is the same as previously described forO. trispinosa. Xeneretmus latifrons, however, has higherDLP+MDP, ILP, and VLP+MVP lateral body plate se­ries counts than O. trispinosa (Tables 4 and 7). Amaxi­mum of five pectoral-fin plates was counted inX. latifrons.

DiscussionSummary comparison of O. tTispl1JOS£'1 ~~~~1

X. latifrons larvae

Larvae of O. trispinosa and X. latifrons can be distin­guished by pigmentation, morphological, and meristiccharacters.

Larvae of O. trispinosa possess a semicircular patchof melanophores that nearly covers the entire caudalfinfold. This character is diagnostic and presentthroughout development. The caudal finfold of pre­flexion X. latifrons lacks pigmentation except for apatch located near the ventral margin of the noto­chord tip. This patch becomes elongate as notochordflexion progresses and becomes a band at the hypuralmargin. This band extends onto the caudal fin andmay cover as much as 20% of its anterior surface.

Preflexion larvae of O. trispinosa possess a smallpatch of melanophores on the anal finfold immediatelyposterior to the origin, X. latifrons larvae have a large

Table 7Meristics ofcleared and stained Xeneretmus latifrons larvae. Specimens between dashed lines were undergoing notochord flexion.

spines rays

Standardlength(mm)

7.4

Dorsal fin----- Anal fin Pectoral

rays fin rays

Pelvic fin Branchi-spines, ostegalrays rays

Neural spines

abdominal caudal total

CentraHaemalspines abdominal caudal

Body plates*

total DLP+MDP SLP LLP ILP VLP+MVP

8.79.510.2-----------------------------------------------------11.912.313.8 7 7 7 15 1,2 6 14 25 39 33 14 28 42 38 38 38 38 3814.5 6 7 7 14 1.2 6 14 27 41 34 14 28 42 38 38 38 38 3821.0 7 6 7 14 1,2 6 15 26 41 35 15 27 42 41 41 41 40 4130.5 7 7 7 15 1,2 6 15 25 40 33 15 26 41 38 38 40 38 3831.8 7 7 7 14 1,2 6 15 25 40 34 15 26 41 38 38 42 38 3839.2 6 6 7 14 1,2 6 15 26 41 34 15 26 41 38 38 40 38 38

*DLP=dorsalateral; MDP=mid-dorsal; SLP=supralateral; LLP=lateralline; ILP=infralateral: VLP=ventrolateral; MVP=mid-ventral.

Busby and Ambrose: Development of larval and juvenile Odontopyxis trispinosa and Xemeretmus latifrons 41 J

unpigmented region. Flexion and postflexion larvae ofO. trispinosa possess a single patch of melanophoreson the anal fin, X. latifrons have two.

Notochord flexion of O. trispinosa begins at approxi­mately 7 .Omm and is completed by 11.8 mm. The larg­est planktonic specimens of O. trispinosa collected were17.7 mm. Settlement probably occurs at approximatelythis size. Notochord flexion of X. latifrons begins atapproximately 8.5 mm and is completed by 11.0 mm.The largest planktonic specimens of X. latifrons col­lected were 22.0 mm.

Xeneretmus latifrons larvae are deeper bodied thanO. trispinosa. Xeneretmus latifrons also has a widerhead than O. trispinosa at all stages of development.Single barbels are present at the corners of the mouthat about 15.0 mm in O. trispinosa and 18.0 mm inX. latifrons. A distinct heart-shaped occipital pit ispresent in O. trispinosa after about 15.0 mm. Post­flexion larvae of each taxon are also distinguishableby adult meristic characters.

Ossification ofmost skeletal elements in O. trispinosabegins earlier and is completed at smaller sizes thanin X. latifrons. Head spination in X. latifrons is gener­ally reduced and dermal plates are absent on the headregion. The caudal-fin ray complement in X. latifrons(2+6+6+1) is notably different than in O. trispinosa(3+6+6+0). Ossification of the pterygiophores support­ing the dorsal and anal fins, and the hypural plate iscomplete by 27.0mm in O. trispinosa, but was not evi­dent in cleared-and-stained specimens of X. latifrons

examined in this study (up to 39.2 mm). This indicatesthat transformation from larval to juvenile stages inX. latifrons occurs at much larger sizes than in 0.trispinosa. Ossification of dermal body plates occurs innearly identical sequence, but X. latifrons has moreplates in the DL+MD, IL, and VL+MV series. Dermalplate formation in X. latifrons is complete at a slightlysmaller size than in O. trispinosa.

The preceding descriptions eliminate the confusionin the literature concerning these larvae which resultedfrom previous misidentifications (page 463 of Matar~seet al. (1989) and Figures A, B, and D from Marliave(1975) are larvae of O. trispinosa misidentified asX. latifrons; Figure C from Washington et al. (1984) isX. latifrons).

Comparison of O. trispinosa and X. latifronslarvae with other known larval agonids

Presently, larvae of 12 of 25 agonid taxa occurring inthe northeastern Pacific Ocean can be identified basedon single illustrations or complete developmental de­scriptions. Of these 12 taxa, only O. trispinosa and X.latifrons described here are complete, illustrated at allstages of development and include discussions of ossi­fication sequence.

By using body morphology, pigmentation, and mer­istic characters. larvae of O. trispinosa and X. latifronsare distinguishable from other northeastern Pacific

Table 8Summary of characters useful in identifying larval and juvenile agonids from the northeastern Pacific Ocean.*

Characters

Body Pectoral Number of PectoralSpecies depth fin length Pigmentation dorsal fins fin rays Vertebrae

Aspidophoroides monopterygius Slender Elongate Light 1 9-10 51-53Bothragonlls swanii Deep Normal Moderate 2 10-12 29-31Chesnonia perrucosa Moderate Elongate Light 2 14-15 34-38Hypsagonus mozinoi Deep Normal Heavy 2 11-12 34H. quadricornis Deep Normal Heavy 2 12-14 36Leptagonusleptorhynchus Moderate Normal Heavy 2 13-15 42-44Ocella dodecaedron Moderate Normal Light 2 14-16 38-39Odontopyxis trispinosa Moderate Normal Moderate 2 13-15 37-42Percisjaponicus Deep Normal Heavy 2 12 40.42Stellerina xyosterna Moderate Elongate Light 2 17-19 34-37Ulcina o[,'iki Slender Elongate Moderate 1 13-16 38-40Xeneretmuslatifrolls Moderate Normal Moderate 2 13--15 39-43

*Sources: Illustrations of A. mOllopterygills, C. perrucosa. H. qlladricornis and S. xyosterna are from Washington et a1.(19841; B. swanii is from Marliave (1975); H. mozinoi is from Matarese et aI. (1989); L. leptorhynchus, O. dodecaedron, andp. japonicus are from Maeda and Amaoka (1988); U. olriki is from Dunbar (1947). Pectoral-fin ray and vertebral counts arefrom Matarese et aI. (19891, with the exception of H. mozinoi and the lower count for P. japonicus which are fromKanayama (1991).

412

agonid larvae for which published illustrations areavailable. (Table 81. Larvae of Hypsagonus mozinoi,H. quadricornis, and Percis japonicus are deeper bod­ied, have notably shorter snout to first dorsal fin dis­tances, are more heavily pigmented, and have lowervertebral and dermal plate counts than O. trispinosaand X. la.tifrolls (Washington et al., 1984; Maeda andAmaoka, 1988; Matarese et al., 1989). Bothragonusswallii larvae have a very similar body morphology toH. mozinoi. H. quadricornis, and P. japonicus but haveconsiderably less pigmentation (Marliave. 19751.

Larvae of Chesnonia uerrucosa and Stellerillaxyostema have similar body morphologies to O.trispinosa and X. latifrons but have notably larger pec­toral fins with bands of pigmentation on or near theirposterior edges (Washington et al., 1984; Matarese etal.. 1989>' Ocella dodecaedron and LeptagonusleptorhYllchus larvae have a similar body morphologyto X. latifrons. However, pigmentation of O. dode­caedron is more sparse and that of L. leptorhynchus isheavier (Maeda and Amaoka, 1988).

Larvae of Ulcina olriki are distinguished from O.trispinosa and X. latifrolls by having larger pectoralfins with pigmented edges and only a single dorsal fin(Dunbar, 1947). Larvae of Aspidophoroides mon­opterygius (= A. bartolli) have extremely slender bod­ies. a long pectoral fin with a low fin-ray count, highervertebral and body plate counts, and a single dorsalfin (Maeda and Amaoka, 1988; Matarese et al.. 1989).Studies such as this and others planned for the futureare the first steps for providing diagnostic informationnecessary to accurately identify early life history stagesof this interesting family of fishes.

Acknowledgments

The authors would like to thank Arthur Kendall Jr.,Ann Matarese (AFSC-Seattle). and Wayne Laroche(Stonefish Environmental and Taxonomic Services) forcritical review of the manuscript. Much needed speci­mens were provided by Wayne Laroche, JeffreyMarliave (VPA), H. Geoffrey Moser (SWFSC), TheodorePietsch (UW), Richard Rosenblatt (Slm, and BruceWing (AFSC-Auke Bay). Douglas Markle (osm pro­vided specimens and station data from collections offthe Oregon coast. Barbara Sumida-McCall illustratedthe specimens shown in Figure 5, A, B, and D, and inFigure 7, A and C (from Moser. ed. I ). Beverly Vinterillustrated specimens shown in Figure 5C and in Fig­ure 7, Band D. Illustrations by Barbara Sumida­McCall were partially funded by the U.S. MineralsManagement Service through an interagency agree­ment (Number 10396).

Fishery Bulletin 9 J (3), 1993

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