2

NOAA Technical Report NMFS 2

Development of Hexagrammids

(Pisces: Scorpaeniformes)

in the Northeastern

Pacific Ocean

Arthur W. Kendall, Jr. and Beverly Vinter

March 1984

u.s. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service
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St., Washington, DC 20235.
NOAA Technical Report NMFS 2

Development of Hexagrammids

(Pisces: Scorpaeniformes)

in the Northeastern

Pacific Ocean

Arthur W. Kendall, Jr. and Beverly Vinter

March 1984

U.S. DEPARTMENT OF COMMERCE

Malcolm Baldrige, Secretary

National Oceanic and Atmospheric Administration

John V. Byrne, Administrator

National Marine Fisheries Service

William G. Gordon, Assistant Administrator for Fisheries
The National Marine Fisheries Service (NMFS) does not approve, recommend or endorse any proprietary product or proprietary material

mentioned in this publication. No reference shall be made to NMFS, or

to this publication furnished by NMFS, in any advertising or sales promotion which would indicate or imply that NMFS approves, recommends

or endorses any proprietary product or proprietary material mentioned

herein, or which has as its purpose an intent to cause directly or indirectly

the advertised product to be used or purchased because of this NMFS

publication.
CONTENTS

Introduction .

Materials and methods .

Results .

Oxylebius pictus .

Zaniolepis species .

Ophiodon elongatus .

Hexagrammos species .

Hexagrammos stelleri .

Hexagrammos decagrammus .

Hexagrammos lagocephalus .

Hexagrammos octogrammus .

Pleurogrammus monopterygius .

Discussion .

Acknowledgments .

Literature cited .

Appendix figures 1-10 .

Figures

1

1

3

3

6

8

11

14

14

20

23

26

30

33

33

35-44

1. Larvae of Oxylebius pictus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2. Ossification of major bones in Oxylebius pictus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3. Larvae of Zaniolepis sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4. Larvae of Ophiodon elongatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

5. Ossification of major bones in Ophiodon elongatus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

6. Representative ventral views of head and tail regions of larvae of Hexagrammos 14

7. Larvae of Hexagrammos stelleri . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

8. Ossification of major bones in Hexagrammosstelleri. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

9. Larvae of Hexagrammosdecagrammus................................................................... 18

10. Ossification of major bones in Hexagrammos decagrammus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

11. Larvae of Hexagrammos lagocephalus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

12. Ossification of major bones in Hexagrammos lagocephalus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

13. Larvae of Hexagrammos octogrammus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

14. Ossification of major bones in Hexagrammos octogrammus 25

15. Larvae of Pleurogrammus monopterygius. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

16. Ossification of major bones in Pleurogrammus monopterygius .. .. .. 28

Tables

I. Summary of previous descriptions of young stages of hexagrammids and material examined in this study 2

2. Adult meristic characters of northeast Pacific hexagrammids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3. Larval characters that allow distinction between Oxylebius pictus and Zaniolepis sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4. Development of meristic structures of Ophiodon elongatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II

5. Guide for identifying northeast Pacific species of Hexagrammos based on meristic characters. . . . . . . . . . . . . . . . . . . . . 12

6. Pigmentation characteristics that distinguish larvae of the four species of Hexagrammos in the northeast Pacific. . . . . 13

7. Development of meristic structures of Hexagrammos stelleri . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

8. Development of meristic structures of Hexagrammos decagrammus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

9. Development of meristic structures of Hexagrammos lagocephalus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

10. Development of meristic structures of Hexagrammos octogrammus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

11. Development of meristic structures of Pleurogrammus monopterygius. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

12. Character states observed among hexagrammid larvae in relation to their states in larvae of Sebastes spp. and

Hemilepidotus spp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

13. Major components of the caudal fin skeleton in hexagrammids, Hemilepidotus, and Sebastes compared with the basic

perciform pattern 32

III

Development of Hexagrammids (Pisces: Scorpaeniformes)

in the Northeastern Pacific Ocean

ARTHUR W. KENDALL, Jr. and BEVERLY VINTER'

ABSTRACT

Larvae of Oxylebil/s pietl/s, Zaniolepissp., Ophiodon elongatl/s, Hexagrammos stelleri, ,-,. deeagramml/s, H.

lagoeephall/s, H. oetogramml/s, and Plel/rogrammus monopterygius are described and iIIustraled from field collections which were supplemenled by laboratory reared specimens ofsome species. Larvae hatch at a rather large size

(3-9 mm), are heavily pigmented, and undergo direct development to an epipelagic prejuvenile stage. Larvae of the

five genera are separable on the basis of body shape, pigmenlation, and meristic characters. Larvae of the four species of Hexagrammos, which are quite similar in appearance, are separable on the basis of a combination ofseveral

pigmentation characters. Developmental evidence indicates thaI Oxylebil/s and Zaniolepis are similar to each other

and are more similar to presumed primitive coltids than the other included genera. Ophiodon is dissimilar to the

olher four genera. Plel/rogrammus and Hexagrammos have similar appearing larvae. Among the species of Hexagrammos a progression of increasing larval pigmentation can be seen from H. stelleri to H. deeagramml/s, H. lagoeephalus, and H. oetogrammus.

INTRODUCTION

The scorpaeniform family Hexagrammidae, the greenlings,

(sensu Rutenberg 1962) is an exclusively North Pacific group

of fairly common generally demersal fishes of the continental

shelf that range in maximum size from Oxylebius pic/us (25

cm) to Ophiodon elonga/us (150 cm) (Hart 1973). The life history pattern observed in species (Oxylebius pic/us [DeMartini

1976]; Ophiodon elonga/us [Giorgi 1981]; Pleurogrammus

monopterygius, Hexagrammos spp. [Gorbunova 1962]) studied so far, is to lay demersal eggs in nests, which are guarded

by the male. An epipelagic prejuvenile stage (Hubbs 1943) occurs during development of most hexagrammids (Gorbunova

1962). Substantial fisheries exist for lingcod, 0. elongatus, and

Atka mackerel, Pleurogrammus monopterygius (U.S. Department of Commerce 1981).

Two major systematic revisions of the group (Quast 1960;

Rutenberg 1962) resulted in several disagreements regarding

the status of certain species and genera and the limits of the

family. Evidence presented herein indicates that larval morphology may assist in resolving these disagreements.

The only major previous work on larval descriptions of hexagrammids was by Gorbunova (1962) who illustrated larvae of

10 species and described in detail 8 of them (Table 1). Material

dealt with here amplifies two descriptions presented by Gorbunova (1962), corrects two of her identifications, and provides descriptions of two species not detailed in her work.

Other descriptive work on larval hexagrammids has dealt with

single species and will be discussed with the species in question

or in the discussion.

MATERIALS AND METHODS

Most specimens used as the basis of this paper were collected

in plankton tows made during cruises off the Pacific coast of

'Resource Assessment and Conservation Engineering Division, Northwest and

Alaska Fisheries Center, National Marine Fisheries Service, NOAA, 2725 Montlake Boulevard East, Seattle, WA 98112.

the United States by personnel of the Northwest and Alaska

Fisheries Center (NWAFC) and the Southwest Fisheries Center. Larvae of Hexagrammos stelleri and H. decagrammus

were reared from eggs collected in nests in Puget Sound. A few

larval specimens from a variety of rearing and sampling programs along the U.S. Pacific coast were used as auxiliary

material. Larval specimens were fixed and stored in 3-5070 formaldehyde solutions buffered with sodium borate. Adult

material from the U.S. National Museum, University of Washington School of Fisheries, and NWAFC ongoing groundfish

surveys was examined for meristic and osteological information.

We attempted to establish two series of five larvae in each

millimeter size interval from hatching to the definitive complement of dorsal and anal fin rays. One series was cleared and

stained following Dingerkus and Uhler (1977) to trace cartilage

and bone formation. The other series was used for morphometric measurements. Limited material was available, so less

than complete series were used in some cases. Some specimens

were used first in the morphometric series and then cleared and

stained. With the cleared and stained series, notes were made

on the presence and shape of various skeletal elements and

which meristic features were stained either blue (cartilage) or

red (bone). Bones were said to have attained their adult shape

when they were entirely red and showed sharp definitive edges.

The vertebral centrum immediately anterior to the urostyle

is called preural centrum 2 in keeping with common practice

(Potthoff 1980), although no fusions of separate elements

were seen in the development of the urostyle. The following

measurements were made in millimeters using an ocular

micrometer in a dissecting microscope once the feature was

formed on the left side of larvae in the morphometric series:

Standard length (SL): Tip of snout to tip of notochord in

larvae before flexion is complete (some consider this notochord length [Potthoff 1980]), to posterior margin of hypural

elements in postflexion larvae.

Preanal length: Tip of snout to middle of anus.

Head length: Tip of snout to posterior margin of opercle.

Snout length: Tip of snout to anterior margin of eye.
Table I.-Summary of previous descriptions of young stages of hexagrammids and material examined in this study.

Material used in this study

Pigment Morphometrics Meristics Detailed osteology

Previous descriptions Length Length Length Length

Taxon References Commenls "10. range(mm) No. range (mm) No. range (mm) No. range (mm)

Oxylebius pic/us Gorbunova 1962 Discussed 6.3-7.3 mm larvae; '50 4.5-20.8 10 7.9-20.8 4 9.3-15.0

illustrated a 7.6 mm specimen,

probably actually Hemilepido/us sp.

Zaniolepis sp. Gorbunova 1962 Discussed 5.2-6.5 mm larvae; 30 2.5-44.4 13.3

illustrated a 6.7 mm specimen as

Zaniolepis la/ipinnis; probably

actually Hemilepido/us sp.

Ophiodon elonga/us Blackburn 1973 Discussed pigment on a 10.3 mm '> 100 9.0-52.0 83 9.0-52.0 30 9.5-28.9, 40.0 8 9.5-28.9

larva, illustrated 8.9, 12.5, and

17 mm larvae.

Marliave 1975 Illustrated and briefly described

9.0-55 mm (TL) specimens.

Phillips and Discussed larval pigment and

Barraclough 1977 metamorphosis briefly; illuslrated

7 specimens 7-80 mm.

Hexagrammos s/elleri Gorbunova 1962 Illustrated and described '> 100 7.8-61.0 104 7.8-61.0 35 8.3-49.5 7 8.3-29.0

10.1-61.5 mm specimens.

Hexagrammos Gorbunova 1962 Illustrated and described '>100 7.4-55.5 100 7.4-55.5 29 12.0-25.6 8.6-30.1

decagrammus 8.7-16.7 mm larvae as

H. superciliosus.

Marliave 1975 Illustrated and briefly

described reared 7-13 mm

(TL) larvae.

Hexagrammos Gorbunova 1962 Illustrated (eggs and 12.6-23.0

lagocephalus mm larvae) and described from

(lagocephalus) material west of long. I:ooW.

Distinct from larvae here

described as H. lagocephalus.

Hexagrammos Gorbunova 1962 Illuslrated and described >100 8.5-34.3 55 8.5-34.3 18 9.9-28.0 6 9.1-28.0

lagocephalus 12.0-65.0 mm specimens as

(superci/iosus) H. decagrammus.

Hexagrammos Gorbunova 1962 Illustrated and described eggs >100 7.5-47.0 91 7.5-47.0 36 8.0-45.0 8.0-29.5

oc/ogrammus and 7.1-46.0 mm specimens.

Hexagrammos o/akii Gorbunova 1962 Illustrated and described eggs

and 6.7-17.8 mm larvae.

Hexagrammos Fukuhara 1971 Illustrated and described reared

agrammus eggs and 8.6-10.2 mm larvae.

[In Jpn.]

Pleurogrammus Gorbunova 1962 Illustrated and described eggs

monop/erygius and specimens (8.0-88.0 mm).

(azonus) Hattori 1964 Illustrated and described 10.0-

32.0 mm specimens. [In Jpn.]

Yusa 1967 Illustrated and described

reared eggs and early larvae

(8.5-10.6 mm).

Pleurogrammus Kobayashi 1958 Illustrated and describeo > 100 9.7-76.0 84 9.7-76.0 43 9.7-28.1 9.8-28.1

monop/erygius 25.7-44.4 mm specimens.

(monop/erygius) [In Jpn.]

Gorbunova 1962 Illustrated and described eggs

and specimens (10.5-30.0 mm).

'Includes reared yolk-sac larvae.

'Includes complete reared larval series.

Eye width: Maximum horizontal distance through eye.

Body depth at pectoral base: Depth of body (exclusive of

dorsal fin structures) at insertion of pectoral fin.

Body depth at caudal peduncle: Minimum body depth between insertion of dorsal and anal fins and origin of caudal

fin.

Snout to dorsal fin length: Tip of snout to origin of dorsal

fin.

Snout to anal fin length: Tip of snout to origin of anal fin.

Snout to pelvic fin: Tip of snout to origin of pelvic fin.

2

Measurements were grouped by I mm SL intervals and the

means of the measurements within each interval were plotted

as percentage of the mean of SL or head lengths within the interval. A computer generated best nonparametric fit curve

based on all the data points was drawn (see Appendix Figures

1-10). Using percentages rather than actual measurements emphasizes changes in relative size of features during ontogeny

and allows easy visual comparison of plots among species.

Limited material of Oxylebius pic/us and Zaniolepis sp. prevented such treatment of their morphology.
Terminology for subdivisions of the larval stage follows

Sumida et al. (1979). In development of hexagrammids, there

is no abrupt metamorphosis at the end of the larval period.

Rather the fish remain epipelagic and continue to grow after

fin formation is complete. During this stage the fish generally

have a pigment pattern in life of a dark green/blue dorsum and

a silvery ventrum. These fish thus match the definition of prejuvenile given by Hubbs (1941, 1943) as do young of several

other families (e.g., Mullidae [Caldwell 1962], Pomatomidae

[Kendall and Walford 1979], and Mugilidae [Anderson 1958]).

These prejuvenile hexagrammids are frequently caught in

neuston nets in the North Pacific, and therefore we will

describe them along with the larvae. There is no definite point

of transition from larva to prejuvenile. Associated with assuming the demersal habits of the adults, the prejuveniles presumably undergo rapid changes in morphology and pigment to

become miniature adults (juveniles), as happens in young

mullids (Hunter 1967).

Specific larvae representing the developmental series of each

species were drawn with the aid of a camera lucida attached to

a dissecting microscope. The least damaged and distorted larvae were selected for illustration; however, the posture of

some was not ideal. Limited changes in posture were drawn in,

to avoid further distortion. The drawings were modified if examination of comparable larvae showed that any substantive

features of the illustrated larva were not representative of the

rest of the material on hand.

Specific identifications of the series were made by comparison with reared material of known parentage when possible.

Pigment patterns and rates of development proved to be the

most useful characters in establishing series. Counts of meristic features on larger larvae in the series linked them to the appropriate adults (Table 2). The most useful meristic features

were the number of dorsal and anal fin rays, principal caudal

fin rays, and myomeres (vertebrae). Geographic occurrence

provided substantiating evidence for identification in some

cases.

RESULTS

Hexagrammid larvae range from about 3 to 9 mm at hatching. They are heavily pigmented with scattered melanophores

overmost ofthe body, particularly dorsally. More, similar pigment is added during larval development. The larvae are rather

elongate but plump in cross section, with large round eyes.

Ophiodon elongatus has a pointed snout and large terminal

mouth. In the other hexagrammid larvae the head is blunt and

the mouth is terminal to subterminal and is upturned when

closed. It appears small in side view, not extending beyond the

middle of the eye, but the size of the gape is substantial because the head is so broad. Development from hatching to

juvenile is direct without remarkable changes in body form or

unusual fin development. In most species the sequence of formation of definitive counts of meristic elements is as follows:

Branchiostegal rays, lower-limb gill rakers, caudal fin rays,

pectoral fin rays, vertebrae, second dorsal and anal fin rays,

and first dorsal and pelvic fin rays. The neural and hemal

arches form before their associated vertebral centra and ossification of the individual centrum begins dorsally and ventrally

as saddle-shaped pieces of bone at the bases of the neural and

haemal elements. Ossification proceeds laterally as the pieces

join each other to form rings which make up the centrum.

Several partially ossified vertebrae could be present at once.

Vertebrae ossify from anterior to posterior, except the urostyle

ossifies before most other vertebrae.

Oxylebius pictus (Painted Greenling)

Figures 1 and 2, Table 3

DeMartini (1976) and DeMartini and Anderson (1980)

described the reproductive biology of this colorful, small,

demersal fish of nearshore rocky habitats that ranges from Baja California to Alaska. Males establish spawning sites during

warmer months where they guard egg masses deposited by one

or more females. The planktonic larval period may last 1-3 mo

after which the juveniles are recruited to rocky substrates.

Gorbunova (1962) discussed larvae 6.3-7.3 mm long and illustrated a 7.6 mm specimen that appears more similar to larvae

of Hemilepidotus sp. (see Richardson 1981) than to those to be

described here as O. pictus.

Larvae hatched and were maintained in the laboratory for

several days from an egg mass of O. pictus that was collected

by diving in Puget Sound, Wash. Similar distinctive larvae

(with highly pigmented pectoral fin buds) occurred in plankton

Table 2.-Adult meristic characters of northeast Pacific hexagrammids. For allspeciesthe normal count forbranchiostegal rays is6 and for pelvic fin rays is 1,5. Caudal fin ray

data from the present study; other data from Quast (1960) except as noted.

Vertebrae Dorsal

First Second

Species Precaudal Caudal (spines) (softrays) Anal Pectoral

Oxylebius pictus 13-15 23-25 15-17 13-16 14-17 14-17

Zaniolepis frenata' 14-15 26-28 21 12 18-19

Zaniolepis latipinnis' 14 28 21-22 11-12 18-20 14

Ophiodon elongatus 23-24 33-35 25-28 19-21 21-25 16-18

Hexagrammos stelleri 20-22 31-34 22-25 18-22 22-25 18-20

Hexagrammos decagrammus 20-22 33-35 21-23 22-26 23-26 18-20

Hexagrammos lagocephalus 20-23 32-34 20-23 20-25 21-24 18-21

Hexagrammos octogrammus 18-19 32-35 18-20 22-25 23-26 18-19

Pleurogrammus monopterygius 26-28 32-35 21-24 24-30 23-28 23-28

'Principal caudal fin rays are supported by the hypurals and parhypurals.

'Miller and Lea (1972); vertebrae: Clothier (1950).

'Miller and Lea (1972); vertebrae: Rutenberg (1%2).

Fin rays

Caudal'

Dorsal Ventral First arch

Secondary Principal Principal Secondary gill rakers

9 7 6 9 11-14

6- 8 7 6 7- 9 11-12

13-15 7 7 12-14 19-28

16-17 7 8 14-15 16-20

12-16 7 9 12-14 15-20

17-22 7 10 15-19 14-18

15-17 7 8 14-15 14-17

16-19 8 11 16-20 22-27

3
A

B

c

o

E

F

....- _ ::... - .""'- .. _...

Figure 1.-Larvae of OxyLebius pic/us: A. 4.5 mm, B. 4.5 mm (dorsal view), C. 6.0 mm, D. 7.4 mm, E. 8.5 mm, F. 10.5 mm.

4
5 Element

CRANIUM

Exoccipital

Basioccipital

Sphenotic

Epiotlc

PrerOtic

Paraspheno!d

Frontal

Nasal

Vomer

Supraoccipital

Parietal

Lateral ethmOId

Lachrymal

Circumorbital 2

C,rcumorbital3

MANDIBULAR REGION

Maxillary

Premal<illary

Dentary

Articular

Angular

PALATINE REGION

Quadrate

Ectopterygoid

Endopterygo,d

Mcropterygoid

Palatine

HYOID REGION

Ce~atohyal

Symplectic

Hyomandlbular

Opercular

Preopercular

Sub opercular

Intcropcrcul:Jr

Urohyal

Epihyal

BRANCHIAL REGION

Pharyngobranchlal teeth

(41'1 arch)

Ceratobranchial (1st arch)

CeralobranctHat 12nd arch)

Ceratl'branchlal (3rd arch)

Ceratobranchral (4th arch)

Ceratobranchiai (5th arch)

Ceralobranchlal gill rakers

(lstarch)

Ceratobranch,al 'l11i rakers

(2nd arch)

Ceratobranch'i)1 9111 rakers

(3rd arch)

Eplbranchial (1st arch)

Eplbranchlal (2nd arch)

Eplbranchlal 13rd arch)

Eplbranchl<ll l4th arch)

Bas,branch,als

Ep'branchlal 'JIll rakers

(lsi arch)

Pharyngobranchlal teeth

13rd arch)

Hypobranchial (lS! arch)

Hypobranchial (2nd arch)

Hypobranchial (3rd arch)

APPENDICULAR REGION

Ctelfhrurn

Coracoid

Supracleithrum

Post-temporal

Post-clellhrum (ventral)

POS1-clclthrum (dolsal)

Pelvic

Scapula

PrOXimal raellals Ipectoral)

CAUDAL REGION

Urastyle

Uronpural

15

Standard length'(mm)

20 25 30 35

Figure 2.-0ssification of major bones in Oxylebius pic/us. Vertical lines represent specimens examined. Hatched area

represents flexion. Horizonlallines: Dotted section represents element present as carlilage, dashed section represents

element partially ossified, solid line represents element with definitive ossified shape.

samples from California, that included larger specimens that

had developed the meristic characteristics of O. pictus.

Pigmentation-On hatching at 4-5 mm the larvae have large

pectoral fin buds heavily pigmented with small melanophores

(Fig. 1). The melanophores cover the internal base and membrane of the fin only but show through this thin tissue to the

external side of the fin. The dorsal surface of the brain is covered with stellate melanophores whose extended edges touch

each other and which are concentrated over the olfactory and

optic lobes and the hindbrain. The pigment over the hindbrain narrows posteriorly to a line of melanophores in the middorsal septum which ends over the gut. A ledge of pigment

visible through the otic capsule appears to line its floor. The

gut cavity is densely covered with evenly spaced melanophores

except along the ventral midline, which is unpigmented. Trunk

pigment is limited to a continuous line of melanophores along

5

the ventral midline; the line originates about five myomeres

posterior to the anus and terminates at the tip of the notochord where it spreads into the fin fold. By 7 mm pigment has

been added to the opercular region and to the external surface

of the pectoral fin bud, and the ventral part of the gut is pigmented across the midline. Pigment has also been added to the

trunk as a diffuse patch of melanophores over the side of the

body between the bases of the just-forming second dorsal and

anal fins. This patch becomes larger during development and

joins the pigment at the back of the head so that by 10 mm the

anterior part of the body posterior to the dorsal and anal fin

insertions is uniformly and densely pigmented. A few melanophores are scattered on the developing caudal fin rays, but the

dorsal and anal fin rays and fin membranes are unpigmented.

By about 16 mm the beginning of the banded pigment pattern

on the trunk, characteristic of the adult, is seen and this pig-
Table 3.-Larval characters that allow distinction between Oxylebius pictus and

Zaniolepis sp. Too few specimens were available to Quantify some character states

to the degree desirable, so relative statements must suffice.

Character state

Character Oxylebius pictus Zaniolepis sp.

3-7 mm SL

Presence of pigment

On isthmus no yes

Laterally above gut less more

On ventral midline of trunk more less

On tip of snout and onto

tip of palate no yes

On internal surface of

pectoral fin base yes no

On lower lip no sometimes

Morphology

Eye size smaller ( < 20070 larger ( > 30070

head length) head length)

Preanal fin fold no(>5 mm) yes( <8 mm)

Pectoral fin length reaches an us reaches an us

by8.0 mm by 5.5 mm

Notochord flexion 7-9mm 5-7 mm

Dorsal indentation on eye no yes

>7 mmSL

Spiny scales cover body no yes

Body shape stout ( < 30070 SL) slender ( < 25070 SL)

ment extends onto the base of the dorsal fin. Through the largest pelagic sizes on hand (20 mm) the pectoral fins are densely

pigmented and the caudal peduncle and caudal fin are practically unpigmented. The tip of the snout and the lips remain unpigmented throughout the pelagic stage.

Morphology-The most outstanding feature of O. pictus

larvae is the large, pigmented pectoral fins. These increase in

size relative to the body as the larvae grow. By about 8 mm

they extend to the level of the anus, and they continue to grow,

reaching the middle of the anal fin by II mm. The notochord

flexes at 7-9 mm. Pelvic fin buds are already present in flexion

larvae. Body parts of a series of 10 specimens from 7.9 to 20.8

mm were measured. As percentages of SL the proportions of

various parts changed during this length interval as follows:

Total length increased from 106 to 125; preanal length fluctuated from 54 to 64; head length fluctuated from 31 to 42; body

depth at the pectoral base increased from 29 to 34; depth at the

caudal peduncle increased from 7.8 to 13; snout to anal fin origin fluctuated from 55 to 64 (larvae> 8.6 mm); snout to dorsal fin origin remained at 31-35 (larvae > 8.6 mm); and the

snout to pelvic fin increased from 29 to 37. As a percentage of

head length the proportion of other body parts changed during

this length interval (7.9-20.8 mm) as follows: Snout length increased from 20 to 23; and eye diameter decreased from 41 to

32. Thus O. pictus larvae, relative to the other larvae discussed

in this paper except Zaniolepis sp., have larger heads, develop

larger caudal fins, are deeper bodied, and have longer preanal

lengths (see Appendix Figures 1-10). Too few specimens of

Zaniolepis sp. were available for conclusive comparisons, but

they appear to have similar proportions to 0. pictus, except

the latter have deeper bodies and smaller eyes.

Developmental Osteology-Only four of our limited supply

of O. pictus larvae were cleared and stained. In a flexion larva

(9.3 mm SL), all principal caudal rays are ossified, but the rest

of the fins have only partial complements of developing unossified fin rays. The vertebrae are forming from anterior to pos6

terior with the first 10 as complete rings, succeeded by 9 partial

rings. The anterior 29 neural spines have ossified, as well as appropriate coordinate hemal spines. In the head region, the six

branchiostegal rays are formed; there are three preopercular

spines and a spine on the posttemporal. By 10.4 mm the notochord has completed flexion and fin rays are approaching their

adult complements. The anterior 32 vertebrae are ossified as

well as their associated neural and hemal spines. By 12.7 mm

there are five preopercular spines and an interopercular spine

as well as a posttemporal and supracleithral spine. In the hypural region two plates are ossified each with a foramen, indicating fusion of hypural I with hypural 2 and hypural 3 with

hypural 4. Complete rings are present for the anterior 38 vertebrae followed by 3 with incomplete rings. Lower limb gill

rakers have increased to five.

Ossification appears to be nearly complete in a 15.0 mm specimen. All meristic features, except gill rakers, possess their

adult complements of elements. The head spines seen on the

12.7 mm specimen are well developed and a second supracleithral spine is present. The hypurals are ossified. Hypural 5

is present, there is a small slit in the dorsal hypural plate (left

from the fusion of hypurals 3 and 4), and there is a pronounced foramen in the ventral hypural plate. Three epurals

can be seen, but only the posterior one is stained and that with

Alcian Blue. There is no neural spine on the urostyle, but preural centrum 2 has two shortened neural spines (specialized

neural arches). One pair of uroneurals is present. There are

7 +6 principal caudal fin rays and 7 dorsal and 6 ventral secondary caudal fin rays.

Ossification of most skeletal elements occurs in a similar sequence to that in other hexagrammids. Development of bones

has already started on larvae smaller than the smallest one that

was cleared and stained (9.3 mm, undergoing notochord !lexion). On the 9.3 mm specimen, the major bones of the cranium, jaws, hyoid arch, and pectoral girdle have begun ossification. The pharyngobranchial teeth and the ceratobranchials

are formed. By the end of flexion (10.5 mm), as in Hexagrammos larvae, the bones of the jaws and in the opercular series

have assumed their adult shapes. Nearly all of the skeletal elements have begun ossification by this stage. Late forming

bones, which begin ossification well after notochord flexion

and do not assume adult shape until near the end of the larval

period (15.0 mm), include the prefrontal, the palatine and

bones of the pterygoid series, several bones of the branchial

alches, the scapula, and proximal pectoral radials.

Zaniolepis (Combfish)

Figure 3, Table 3

This genus contains two species of rather small (maximum

30 cm), uncommon demersal fishes occurring from Baja California to southern Oregon (Z. frenata) and from Baja California to British Columbia (Z. latipinnis) in shallow waters to

400 m (Miller and Lea 1972). Little is known of their life history (Johnson and Adams 1970). Alternative classifications

have put these fish in separate genera (Rutenberg 1962: Xantodes frenata and Z. latipinnis) and in their own family (Quast

1960: Zaniolepidae). Although larvae on hand of Zaniolepis

cannot be correlated with certainty with either species, we suspect we have only one species, since there is little variation

among specimens in larval characters. The larvae are quite

similar to 0. pictus in pigment and morphology.
A

.... -

B

c

.. ;. ":. ",

. .. ":')1 .,.,.

... .:.....

., '.. '"" .,,:,::

D

E

Figure 3.-Larvae of Zalliolepis SII.: A. 4.0 mm, B. S.O mm, C. 6.2 mm, D. 7.7 mm, E. 9.S mm.

7
Gorbunova (1962) illustrated a 6.7 mm larva as Z. latipinnis

collected off California and described specimens from 5.2 to

6.5 mm long. The illustrated larva appears more like one of

Hemilepidotus sp. (Richardson 1981) than of the Zaniolepis

sp. in our collection. The larvae Gorbunova (1962) discussed

were too small to have definitive meristic characters to allow

unquestioned identification.

The larvae described here were collected in plankton tows

off California. Definitive meristic characters of the genus are

formed on specimens 10 mm long. Pigment patterns and general morphology of these specimens is seen in smaller specimens in the series which have not yet developed adult meristic

complements. The most outstanding feature of these larvae is

the presence, in specimens as small as 7 mm, of fine, spiny

scales on the body that give the skin of the adult a characteristic texture. These larvae are very similar to those of 0. pictus

in body shape and pigmentation, including the heavily pigmented pectoral fins. Only features brought out by careful examination will distinguish small larvae of Zaniolepis sp. from

those of O. pictus (Table 3). The presence of snout pigment in

Zaniolepis sp. and its absence in 0. pictus are readily observable and diagnostic. The external surface of the base of the

pectoral fin is pigmented by 7 mm in O. pictus, but remains

practically unpigmented until at least 13 mm in Zaniolepis sp.

Inadequate material was available for more than a general

description of development.

Pigmentation-On the smallest larvae on hand (2.5 mm) a

distinctive pigment pattern is evident that persists throughout

the larval period (Fig. 3). Numerous small, closely spaced

melanophores give a pigmented appearance to the anterior

half of the larvae. Some spots are present in the opercular

region and the top of the head is uniformly covered with

melanophores, except for a less pigmented patch over the optic

lobes of the brain in some. This pigment extends anteriorly to

the tip of the snout and continues onto the palate. Posteriorly

it covers the nape and spreads onto the flank of the abdominal

region and is continuous with pigment covering the lateral surface of the gut. The hindgut is covered with more closely

spaced melanophores. Ventrally, pigment crosses the midline

in the cleithral and isthmian regions but is absent in the midgut

region. A few spots are present in the midventral septum of the

trunk. The internal surface of the bases and blades of the pectoral fins are heavily pigmented with fine melanophores. The

most noticeable change in larvae up to 7 mm is the extension of

the lateral pigment to about 10 myomeres posterior of the

anus, mainly on the ventral part of the body. This area of pigment continues to enlarge, and by 10 mm the trunk anterior to

the caudal peduncle is covered with melanophores. As this

happens the anterior ventral midline melanophores disappear.

Median fin pigment is confined to a few melanophores on the

principal caudal fin rays and fin membrane. In 14-24 mm specimens the trunk is uniformly densely pigmented to the base of

the caudal fin, and the pectoral fins are even more densely pigmented. The external surface of the bases of the pectoral fins is

practically free of pigment throughout the series on hand.

Morphology-Larvae of Zaniolepis sp. are slender with a

moderately short gut. The smallest larvae on hand (2.5 mm)

still have yolk and are presumed to have hatched near that size.

The pectoral fins are large throughout larval development and

develop rays at 5 mm, before notochord flexion, which occurs

at about 6 mm. At that time the central principal caudal fin

rays are visible and the dorsal and anal fin bases have started

8

to form. Pelvic fin buds are also present. By 8 mm most median fin rays are countable, except for secondary caudal rays.

The pelvic fins remain as small buds until rays develop at

about 12 mm. The spiny scales characteristic of the adult are

first seen on the head and abdominal region of larvae 6.5-7.0

mm. By 9.5 mm they cover the entire body except the snout

and extend onto the fin membranes of the pectoral and caudal

fins. A small preanal fin fold is present in larvae up to about 8

mm, and the hindgut is slightly enlarged and protrudes from

the body. The eye is relatively smaller than that of O. pictus

and tends to have an indentation dorsally in larvae < 9 mm.

Developmental Osteology-From the limited number of

specimens available, a 13.3 mm larva that was cleared and

stained has adult values of all meristic characters except gill

rakers. The first two anal rays appear as weak spines, and the

dorsal spines do not appear fully developed, so their relative

lengths, which are identifying characters in adults, cannot be

determined. Spiny scales cover the entire body, all fins, and

most of the head. Several bones of the head are spine bearing.

There is one spine each on the nasal, on infraorbital 3, and on

the interopercle. Infraorbital 1 (lachrymal) has five spines

along its ventral margin and one produced out of the center of

the bone. The posttemporal has a bifurcate spine with the anterior point being smaller than the posterior point. There are

two small spines on the supracleithrum. The left preopercle

has six spines and the right has seven. It is quite possible that

more and/or elaborate head spines develop later.

In the caudal region, ossification appears incomplete (e.g.,

t:-Jere are no epurals, and no modified neural arch on preural

centrum 2); however. it seems that the parhypural and hypurals

1 and 2 are fused, hypurals 3 and 4 are fused, and there is no

indication of hypural 5. A pair of small uroneurals is present.

Ophiodon elongatus (Lingcod)

Figures 4 and 5, Table 4, Appendix Figures 1-10

Ranging from Baja California to the northern Gulf of

Alaska, this large (maximum 150 cm), aggressive, demersal

piscivore is of considerable economic importance as a food fish

and as a quarry of sportsmen (Hart 1973). Males guard large

egg masses in rocky shallow areas in winter. The larvae become

neustonic; the juveniles settle in sandy areas in spring and

gradually move to the deeper rocky habitat of the adults. Larvae have been collected in several plankton surveys within the

species' range and they have been illustrated and described

briefly (Blackburn 1973; Phillips and Barraclough 1977). They

are described here in more detail based on laboratory-reared

hatchlings and a developmental series of plankton-collected

specimens collected mainly off California. Larger pelagic specimens (30-52 mm) collected off southern British Columbia

were also examined.

Pigmentation-At hatching (9.3 mm) the larval pigment

pattern is ali'eady established (Fig. 4). The overall appearance

is of a heavily, uniformly pigmented larva with unpigmented

fin folds and an unpigmented caudal region. The optic lobes of

the brain are densely covered with melanophores. Some spots

are also present on the olfactory lobes and between the nares.

The hindbrain is covered with a medial patch of pigment that

divides into two lines that straddle the middorsal septum

reaching posterior to above the end of the gut. At that point

they join and run along the middorsal septum for most of the

rest of the length of the body. Pigment extends onto the flank
A

B

------------

'.~ ": .' ' ......

c

D

E

Figure 4.-Larvae of Ophiodon e/ongatus: A. 9.8 mm, B. 12.2 mm, C. 15.4 mm, D. 19.0 mm, E. 36.0 mm.

of the trunk and joins more closely spaced melanophores that

extend dorsally from a line along the midventral septum. The

midventral pigment line originates about six myomeres posterior to the anus and does not extend posteriorly quite as far as

the dorsal line. Dorsolaterally the peritoneum is covered with

melanophores, and there is a spot in the opercular region on

some specimens. The base of the isthmus may have a melanophore. As the larvae grow, pigment is added to certain parts of

the pattern seen in the hatchlings; the most significant changes

occur in the head region. By 12 mm there are pigment spots on

9

the jaws, in the suborbital, opercular, and cleithral areas, and

the isthmus is densely pigmented. More of the lateral surface

of the peritoneum is pigmented, and the trunk flank pigment

extends forward to the gut. To a variable extent there is an indication of a line of fine pigment spots along the midlateral

septum that increases in intensity with growth. The dorsal line

of pigment spots straddles the middorsal septum for nearly all

of its length-coincident with the base of the dorsal fin. Internally there is heavy pigment along the vertebral column medially just dorsal and ventral to the vertebrae. None of the fins
CAUDAL REGION

Urostyle

Uroneural

PALATINE REGION

Quad,ate

EctoptPrygold

El1dopterY~UIl.J

Metopterygoid

Palatine

MANDIBULAR REGION

MaxIllary

Prem(lxlliary

i)entary

Artkular

Anf)ular

25 30 35

----------

Standard IBrrgth (rlmJ

5 20

APPENDICULAR REGION

Cleithrum

Coracoid

Supraclelthrum

Post-temporal

Post-clp·thrum (ventral)

Post-c1eithrum (dorsal)

PelvIc

Scapula

Proximal radials (pectoral)

HYOID REGION

CcratohyaJ

Symplectic

Hyomandlbular

Orercular

Preupercular

Subopercular

lntcrop~rcular

Urohyal

Epihyal

CRANIUM

EXOCClpltal

BasIoccIpital

Sphlmulic

EPiOtiC

PterOtlC

Parasphenold

Frontal

Nasal

Vomer

Sup, aocclpitdl

Parietal

Lateral ethm<.>id

Lachrymal

Circumllrl.Jltal2

C,rcumorbltal 3

BRANCHIAL REGION

PharyngohranchlJlteeth

(4th arch)

C",ratobranchial (lst ,HI"h)

Ceratobranchiai (2nJ arch I

Cera<obranchlal (3rrl drdl)

Cf'r<ltobrancl,ial 14th arch)

Ceratobranchial (5th ~(d-,)

Ceralobrilnchi31 gilt l .. k~I'

(1st arch)

Ceratobranchi,J1 gill 1<'I"(..'rs

(2nd arch)

Ceratobranchlal gill rakers

(3rd arch)

Eplbranchial (1st a,chl

Epibranchial (2nd arch)

Epibranchial (3rt.J arch)

Epibranchlill (4th archl

Baslbranchials

Epibranchial gill r<.lker~

(1st arch)

Pharyngobranchldl teeth

(3rd archl

Hypobranchial (lsI arch)

Hypobranchial (2nd arch)

Hypobrdnchial l3nl atch)

Element

Figure 5.-0ssifieation of major bones in Ophiodon elongatus. Symbols as in Figure 2.

develop pigment during the larval stage. There is remarkably

little change in pigmentation from the 12 mm larva to the largest specimen on hand (52 mm).

Morphology-A series of 83 specimens 9.0-52.0 mm was

measured to document body shape which changes little during

development. The larvae are elongate, have long pointed

snouts with large mouths, and a long gut. The lower jaw protrudes noticeably in larvae > 12 mm. Notochord flexion occurs in larvae 11-15 mm. There is a preanal finfold throughout

the larval period. Two small blunt spines occur on the preopercular margin in larvae> 18 mm and four spines are present in

40 mm fish. There is no marked transformation from larvae to

juveniles in O. elongatus and the fish seem to remain epipelagic until well after the larval period, which ends at about

30 mm.

Developmental Osteology-A series of 30 larvae from 9.5 to

28.9 mm and a 40.0 mm specimen were cleared and stained to

trace osteological development (Table 4). Meristic elements

develop over a wide length range: The branchiostegal rays had

started to ossify on the smallest specimen examined, but the

pelvic fins, gill rakers, and secondary caudal rays had not

reached their adult complements on a 28.9 mm specimen. Elements in most meristic featur,;:s start to ossify during flexion

(10.5-15.5 mm). The vertebrae form from anterior to posterior, except that the urostyle is among the first centra to form.

Nonmeristic bones that have started to ossify in the smallest

specimens examined include the cleithrum, opercle, maxillary,

premaxillary, angular, and dentary (Fig. 5). During flexion,

several bones in the head region start to ossify. No early

development of the posterior coracoid process in cartilage is

seen; in contrast to its prominent development in some other

hexagrammid larvae (Hexagrammos lagocephalus, H. octogrammus, and Pleurogrammus monopterygius). Also in O.

elongatus, the bones of the jaw, which reach adult shape dur10
Table 4.-Developmenl of meristic struclures of Ophiodon elongatus. Specimens between dashed lines are undergoing notochord flexion. The first observation of count within

adult range is underlined.

Fins

Vertebrae' Caudal

Partial Complete Partial Complete First Second Anal Pectoral Pelvic Secondary Principal Principal Secondary Upper Lower

BranchiGill rakers ostegal _

rays

Dorsal Upper Lower Standard -------------

length Precaudal Caudal

(mm)

9.5

9.5

lOA

2

2

3

---------------------------------------------------------------------------------------------------------_..--------------------_. 10.5 5 3 3 4

11.2 8 1. 1- 5 6

11.7 8 7 7 5 8

12.5 5 6 6 5 4

12.5 6 6 7 5 5

12.5 7 6 7 5 7

13.5 8 7 7 5 8

13.5 8 6 7 6 8

13.5 2 2 9 7 7 6 9

13.5 2 4 8 7 7 6 9

14.0 4 9 7 7 6 7

14.8 16 7 23 10 2 7 7 6 10

15.0 17 6 23 II damaged damaged 7 6 10

-------------------------------------------------------------------------------------------------------------------------------_. 15.5 16 7 26 I 12 2 7 7 2 6 14

16.0 17 6 25 1 11 I 7 7 I 6 12

16.2 13 9 28 1 16 17 13 3 7 7 3 6 I 13

17.5 13 9 30 I 18 19 14 4 7 7 3 6 I 13

17.5 II 13 31 I 5 18 19 14 4 7 7 3 7 I 13

17.5 3 21 32 I 8 18 20 14 4 7 7 3 6 I II

18.2 23 15 18 II .!2 18 15 5 7 7 4 6 I 11

18.3 23 7 26 12 19 21 15 5 7 7 4 6 I 14

19.8 23 2 31 16 20 22 1& 6 7 7 5 6 2 16

21.3 24 I 32 25 21 23 17 1,3 7 7 7 7 7 2 14

22.0 23 2 32 25 21 24 17 1,3 7 7 7 6 6 2 16

22.5 23 33 25 22 24 17 1,3 8 7 7 7 6 3 17

24.0 23 32 25 21 23 18 1,4 9 7 7 8 6 3 17

28.9 24 34 27 21 25 17 1,4 9 7 7 8 6 2 14

'Vertebrae in hexagrammids begin ossification as dorsal and ventral saddle-shaped pieces of bone which join each otherlaterally to form rings that further ossify to attain their definitive shape. Vertebrae were considered "partial" if ossification had begun, but the dorsal and ventral sections had not fused, after which a vertebra was considered "complete."

ing flexion, and the ceratobranchials, which reach it shortly

after flexion, are precocious relative to their development in

other hexagrammids. Shortly after flexion, at about 17 mm,

most of the skeletal elements are partially ossified, and the

cleithrum reaches its adult shape. Most bones of the hyoid

arch attain their adult shapes at about 20 mm, and most of the

bones of the pectoral girdle have staTted to ossify by about 24

mm. The caudal skeleton begins to ossify at about 14 mm; during flexion and by the end of flexion the urostyle and four

plates that support the principal caudal rays are seen: Two

hypurals that support the dorsal principal caudal rays, a large

hypural (hypurals 1 and 2), and the parhypural that support

the ventral caudal rays. By 28.9 mm three epurals (the anterior

two are ossified) and a pair of tiny uroneurals are present and

the dorsal hypurals (3 and 4) have fused into one plate. The

posterior epural is ossified by 40 mm. Hypural 5 is absent.

Hexagrammos Species

Figures 6-14

Larval development of the four northeastern Pacific species

of Hexagrammos is similar to that of the northwestern Pacific

species, H. o/akii (Gorbunova 1962) and H. agrammus (Fukuhara 1971). Therefore a general description of larvae of the

northeastern Pacific species of Hexagrammos will be given,

followed by information to distinguish these species. Specific

identity of larvae was established by comparing pigmentation

on smaller larvae with that on larger larvae and prejuveniles

that had distinguishing meristic characters (Table 5). Identity

of field-caught H. decagrammos and H. s/elleri larvae was

confirmed by comparisons with larvae reared from known

parents.

Pigmentation (Table 6, Figure 6)-In preflexion larvae the

typical hexagrammine (Hexagrammos and Pleurogrammus)

heavy pigment pattern is evident, and additional pigment appears during development. The snout, lower jaw, and dorsal

surfaces of the optic lobes are covered with numerous melanophores. The isthmus and gill filaments may have a few pigment

spots. A few spots are present in the cheek and opercular area,

and a melanophore may be present on each angular. Two lines

of pigment spots run along the dorsal midline from the optic

lobe pigment to near the tip of the notochord. These lines join

each other across the dorsal midline on the caudal peduncle,

and to some extent along the area where the dorsal fin forms.

11
Table 5.-Guide for identifying northeast Pacific species of Hexagrammos based on meristic characters.

Based on principal ventral caudal fin rays

Principal ventral caudal rays = 8

precaudal vertebrae = 20-22 = H. stelleri

precaudal vertebrae = 18-19 = H. oClogrammus

Principal ventral caudal rays = 9

H. decagrammus

Principal ventr~1 caudal rays = 10

H. lagocephalus

Based on extremes of meristic characters

Dorsal fin spinous rays

18-19 = H. octogrammus

20-23 = indeterminate

24-25 = H. stelleri

Dorsal fin softrays;

18-19 = H. stelleri

20-25 = indeterminate

26 = H. decagrammus

Total anal fin rays

21 = H. lagocephalus

22-26 = indeterminate

Precaudal vertebrae

18-19 = H. oClogrammus

20-23 = indeterminate

Caudal vertebrae

31 = H. stelleri

32-35 = indeterminate

Total vertebrae

50 = H. octogrammus

51-57 = indeterminate

The dorsolateral surface of the peritoneum is pigmented. The

flank is variably pigmented with internal and superficial pigment spots dorsal and ventral to the notochord. Deep internal

pigment is present just dorsal and ventral to the developing

vertebral column. Ventral midline pigment is present in preflexion larvae of some species but is present only later in

development in other species. This pigment consists of a row

of pigment spots along each side of the area where the base of

the anal fin forms and extends onto the caudal peduncle where

it is intensified in some species. The tip of the notochord has a

line of a few melanophores along its dorsal surface in some

species.

As the larvae grow, the most conspicuous area of added pigment is the flank where both superficial and internal spots

eventually cover the entire lateral surface of the body giving

the fish a uniformly dark appearance. The caudal fin rays and

fin membrane become pigmented as they develop, particularly

at their bases. The peritoneal pigment extends ventrally to

cover the gut cavity.

Morphology-Hexagrammos larvae hatch at between 7 and

9 mm and notochord flexion occurs between 12 and 18 mm.

No remarkable changes in body shape occur during development (Appendix Figures 1-10). Hexagrammos larvae have

blunt heads with large eyes and small subterminal or upturned

mouths. The body is elongate and tubular. The gut is short and

compact. Among the four species of Hexagrammos studied

here, H. lagocephalus is deeper bodied at the pectoral fin and

12

at the caudal peduncle than the others. There is no marked

transformation at the end of the larval period, rather the fish

remain epipelagic until about 40-50 mm, when they become

demersal and develop pigmentation and body shape characteristic of the adults.

Developmental Osteology (Tables 7-1O)-Examination of

cleared and stained developmental series of each species of

Hexagrammos showed that the sequence of formation and

ossification of most bony elements follows a similar pattern

among the species. Among meristic elements, branchiostegal

rays are first to form, starting in preflexion larvae, and attaining adult counts during flexion. Principal caudal fin rays ossify

during flexion. Secondary caudal fin rays are gradually added

beginning during flexion and continuing into the prejuvenile

stage. First arch gill rakers form before or during flexion and

continue to form until late in the prejuvenile stage. Pectoral

fin rays start to develop during flexion and adult counts are attained in the early postflexion period. Vertebral development

is from anterior to posterior, with abdominal vertebrae ossifying during and shortly after flexion. The urostyle ossifies

before the rest of the caudal vertebrae, which ossify late in the

flexion stage and complete development rapidly. Several vertebrae are in various stages of development on each flexion and

early postflexion larva. The second dorsal and anal fin rays

develop rapidly shortly after flexion, followed by the first dorsal fin spines and finally the pelvic fin rays which do not form

until early in the prejuvenile stage.

Evidence of the beginning of development of the caudal

complex is first seen concurrent with the start of flexion when

the principal caudal fin rays start to form. At this time the

hypurals start to develop as cartilage. PosteriorlY a medially

bifurcated cartilaginous wedge is seen representing the dorsal

hypural plate (hypurals 3 and 4). Anterior to this a trapezoidal

shaped piece of cartilage with two openings represents the ventral hypural plate (parhypural and hypurals I and 2). Later

during the flexion period the three epurals develop from cartilage followed by a single thin pair of bony uroneurals. The

urostyle is the first structure to ossify followed by the hypural

plates, the uroneurals, and the epurals. A shortened neural

spine is present on the urostyle and on preural centrum 2 the

neural spine is shortened and is double in some individuals.

The hemal spines on the first two preural centra are autogenous. The principal caudal fin ray count is 7 dorsal and 8 to

10 ventral, depending on the species (H. stel/eri and H. octogrammus: 8; H. decagrammus: 9; H. lagocephalus: 10). Dorsal

and ventral secondary caudal fin rays are numerous (12-19).

The sequence of ossification of bones in the species of Hexagrammos examined follows a fairly constant pattern (Figs. 8,

10, 12, 14). The first bone to ossify is the cleithrum, which is

present at hatching. The bones associated with the mouth

(maxillary, dentary, and premaxillary) ossify before flexion.

The exoccipital at the base of the skull; the quadrate, symplectic, and hyomandibular of the suspensorium; ceratohyal and

epihyal and the ceratobranchials of the branchial apparatus;

the pharyngobranchial teeth; and an elongate posterior coracoid process form as cartilage in preflexion larvae.

During flexion, in the skull the parasphenoid and exoccipital

start to ossify and more of the occipital bones and bones of the

otic region are present as cartilage. The rest of the bones of the

mandibular arch, those in the opercular series, the ceratobranchials, and the supracleithrum and posttemporal also start

to ossify. Shortly after flexion is complete, most of the bones
Table 6.-Pigmentation characteristicsthat distinguish larvae ( <30 mm; > 25 mm meristic characters permit separation) of the four species of Hexagrammos in the northeast Pacific. Considerable individual variation in number, position, and

degree of contraction of melanophores (spots) was observed; the modal conditions for the species are noted here so individuals may not display all characteristics mentioned.

Pigment area

-w

Species

H. stelleri

H. decagrammus

H. lagocephalus

H. octogrammus

Postanal ventral midline

Absent until about 15 mm, then starts to

form posteriorly (on caudal peduncle),

later ("'23mm) forms along entire base of

anal fin.

Absent until about 13 mm, then starts to

form along anal fin base near its origin.

By IS mm along anal fin base to caudal

peduncle. Spots more numerous and

smaller than on H. lagocephalus.

Present throughout development.

Particularly dense on caudal peduncle.

Spots along anal fin base tend not to

touch each other. Spots uneven in spacing

and size to create irregular line. Few spots

anterior to origin of anal fin.

Present throughout development. Extends

from anus to base of caudal fin. Dense on

caudal peduncle. Spots tend to touch each

other to create a continuous straight line.

Superficial lateral trunk'

Absent or faint until 9 mm. Then ventral

row densest. Concentrated above and

below lateral midline.

Some present at hatching ("'S mm).

Ventral row densest. Longer, denser, and

broader than on H. stelleri.

Faint at hatching ("'S mm). Ventral row

of more smaller spots than in H. stelleri

or H. decagrammus. Posterior part of

dorsal row nearly as dense as ventral row

at < 15 mm, then uniform.

Absent or faint at hatching ("'7 mm).

Denser on caudal peduncle than anteriorly.

Spots smaller than on H. stelleri or H.

decagrammus but larger than on H.

lagocephalus.

Isthmus

Absent at hatching. Anterior half

gradually becomes pigmented starting at

IOmm.

About four equal sized and spaced spots

form on each side making a "V." Present

from about 9 mm on.

An anterior medial spot and about five

equal sized and spaced spotS present from

about 9 mm on.

Present-anteriormost and posteriormost

spots larger than others. Anterior, medial

spot seen at 10 mm, up to five on each

side of isthmus seen at 12 mm. Spacing

uneven.

Notochord

tip

Absent

Absent at

hatching but

forms by

about 10 mm.

Present

Present

Gular'

Absent

Present

>12mm

Present

>llmm

Absent

Internal pectoral

fin base'

(>17mm)

Present

Inconsistently

present

Absent

Present

Other

Lower jaw pigment

on tip only.

Two forms based on

degree of contraction

of melanophores,

particularly the

lateral trunk ones.

Tends to be clear

area between optic

lobes.

Heavy pectoral base

pigment. Pigment

continuous between

optic lobes.

'On specimens larger than about 20 mm SL the lateral aspect of the trunk is uniformly densely pigmented in all species.

'A few spots occur ventrally just anterior to the isthmus.

'One to a few spots occur near the dorsal edge of the internal surface of the pectoral fin base.
Hexagrammos /agocepha/us

Hexagrammos ste//eri

Hexagrammos octogrammus

Figure 6.-Representative ventral views of head and tail regions of larvae of Hexagrammos (16·18 mm). A. H. stelleri, B. H. decagrammus. C. H. lagocephalus. O. H.

octogrammus.

of the skull are visible, either as cartilage or bone. The bones

of the jaws and those of the opercular series assume thei: adult

shapes.

During the postflexion period, most of the rest of the bones

start to ossify, and the entire skeleton approaches its adult appearance. Late-forming bones include circumorbitals, palatine, basibranchials, hypobranchials, and proximal radials of

the pectoral fin.

Hexagrammos stelleri (Whitespotted Greenling)

Figures 6, 7, and 8

This greenling occurs in rocky coastal areas from Washington to northern Japan (Quast 1960). Spawning of blue demersal eggs is reported to occur during every season (Gorbunova

1962; Hart 1973). Larvae were illustrated and described by

Gorbunova (1962).

The larvae illustrated here were reared from eggs found in

Puget Sound. Similar larvae from plankton collections in the

Gulf of Alaska were used for morphometric and osteological

observations.

Larvae of H. stelleri are the least pigmented larvae in the

genus (Table 6). Postanal ventral midline pigment is absent until about 15 mm, when it starts to form on the caudal peduncle

14

and at about 23 mm forms along the anal fin base. Superficial

lateral trunk pigment is absent or faint until the larvae reach

about 9 mm, then the ventral aspect is more densely pigmented

than the dorsal aspect. The isthmus is pigmented anteriorly in

larvae larger than 10 mm. Only the tip of the lower jaw and the

angular are pigmented, while the entire lower jaw is pigmented

in the three other species.

Hexagrammos decagrammus (Kelp Greenling)

Figures 6, 9, and 10

The geographic range of the rather abundant kelp greenling

is extensive-from the Aleutians to southern California (Miller

and Lea 1972). Large masses of pale blue eggs are laid in the

fall (Hart 1973) off British Columbia and in late summer to the

north (Gorbunova 1962). Larval development was described

by Gorbunova (1962) under the name H. superciliosus. Larvae

illustrated and described here were either reared from eggs or

gleaned from plankton samples. Specimens from off California were about 2 mm shorter at comparable stages of development than those off Alaska. The sizes reported here apply to

the larvae from Alaska.

On hatching at about 8.0 mm H. decagrammus has no pigment along the postanal ventral midline, but there is a little
A

B

c

o

E ." ~',-. ," .~ ~.

.....:...., . :. \', '" ..•..•...:.:: . " ... ':.':.':......

Figure 7.-Larvae of Hexagrammos steller;: A. 8.0 mm, B. 9.2 mm, C. 10.4 mm, D. 13.8 mm, E. 33.0 mm.

15
CAUDAL REGION

Urostv1e

Uroneural

PALATINE REGION

Quadrate

Ectopterygoid

Endopterygoid

Metopterygoid

Palatine

MANDIBULAR REGION

Maxillary

Premaxillary

Dentary

Articular

Angular

25 30 35

-----+-------1--

- - - - - t-------+--

====::=.~~

- - - - - - +-------1--

::=-----.= +========+:=

Standard length (mm)

10 20

........... {>..,~>t<'~'\~

5

CRANIUM

Exoccipital

Basioccipital

Sphenotic

Epiotic

Pterotic

Parasphenoid

Frontal

Nasal

Vomer

Supraoccipital

Parietal

Lateral ethmoid

Lachrymal

Circumorbitat 2

Clfcumorbital 3

HYOID REGION

Ceratohyat

Symplectic

Hyomandibular

Opercular

Preopercular

Subopercular

Interopercular

Urohyal

Epihyal

BRANCHIAL REGION

Pharyngobranchial teeth

(4th arch I

Ceralobranchial (lSI arch)

Ceratobranchial (2nd arch)

Ceratobranchial13rd arch)

Ceratobranchial {4th arch)

Ceratobranchia( (5th arch)

Ceratobranchl31 gill rakers

(1st arch)

Ceralobranchial gilt rakers

(2nd arch)

Ceratobranchial gill rakers

13rd archl

Epibranchial (lsI arch)

Epibranchial (2nd arch)

Epibranchial (3rd arch)

Epibranchial (4th arch)

Basibranchials

Epibranchial gill rakers

(1st arch)

Pharvngobranchial teeth

(3rd archl

Hvpobranchial (lSI arch)

HVpobranchial (2nd arch)

Hypobranchial (3rd arch)

APPENDICULAR REGION

Clelthrum

Coracoid

Supracleithrum

Post-temporal

Post-c1elthrum (ventral)

Post·cleithrum (dorsal)

Pelvic

Scapula

PrOlCimal radials (pectoral)

Element

Figure S.-Ossification of major bones in Hexagrammos stelleri. Symbols as in Figure 2.

16
Table 7.-Development of meristic structures of Hexagrammos slelleri. Specimens between dashed lines are undergoing notochord nexion. The first observation of count within

adult range is underlined.

Fins

Vertebrae' Caudal

Standard BranchiPrecaudal Caudal Dorsal Upper Lower Gill rakers ostegal length

(mm) Panial Complete Panial Comrlete First Second Anal Pectoral Pelvic Secondary Principal Princiral Secondary rays Upper Lower

8.3

9.4 3

9.6 3

10.2 3

10.4 3

11.7 4

11.7 5 2

-------------------------------------------------------------------------------------------------------------------------------- 12.4 4 4 5 3

12.6 4 4 5 4

13.3 5 3

13.8 20 32 II 7 .§. 6 6

14.6 20 30 13 7 8 6" 6

14.9 N 7 27 13 2 7 8 2 6 7

15.0 15 5 31 14 7 8 6 7

-------------------------------------------------------------------------------------------------------------------------------- 15.3 20 II 22 13 2 7 8 2 6 7

15.5 21 7 25 16 3 7 8 2 6 7

15.6 2 19 28 3 14 2 7 8 2 6 8

16.8 21 4 29 20 23 18 6 7 8 6 6 8

17.1 21 II 20 23 20 1,2 8 7 8 7 6 I 9

18.5 21 33 22 21 24 19 1,4 10 7 8 10 6 I 9

18.7 21 32 21 21 23 19 1,3 8 7 8 8 6 I II

19.7 20 34 12 20 24 20 1,3 7 7 8 9 6 2 9

20.6 20 33 24 18 24 19 1,4 damaged 7 8 10 6 2 9

20.7 21 32 22 20 22 20 1,3 10 7 8 9 6 2 9

21.9 21 32 22 20 25 20 1,4 II 7 8 II 6 2 9

21.9 20 34 23 21 26 19 1,4 10 7 8 9 6 2 10

22.9 21 32 22 21 24 20 !.2 14 7 8 13 6 2 10

22.9 21 33 23 21 25 19 1,5 15 7 8 13 6 3 10

24.1 21 33 23 22 24 19 1,5 14 7 8 14 6 3 9

29.0 21 32 23 22 24 19 1,5 17 7 8 15 6 3 10

29.6 20 32 22 21 25 20 1,5 i6 7 8 15 6 4 II

34.0 21 32 23 21 25 19 1,5 18 7 8 16 6 4 12

40.6 21 33 22 22 25 20 1,5 17 7 8 15 6 3 II

44.2 20 34 24 21 25 20 1,5 19 7 8 17 6 3 12

49.5 21 33 23 21 25 19 1,5 17 7 8 16 6 3 II

'Venebrae in hexagrammids begin ossifica.ion as dorsal and ventral saddle-shaped pieces of bone which join each other laterally to form rings that further ossify to attain their definitive shape. Venebrae were considered "panial" if ossification had begun, but the dorsal and ventral sections had not fused, after which a vertebra was considered "complete."

17
A

B

c

.~ .'.

',":."

. ~. ~;•.. -!: .

~)

, ,/'~",~i' ":=""~~:~~~

~/

o

E

F

Figure 9.-Larvae of Hexagrammos decagrammus: A. 9.8 mm, B. 10.6 mm, C. 13.3 mm, D. 15.0 mm, E. 18.2 mm, F. 31.0 mm.

18
CAUDAL REGION

Urostyle

Uroneural

PALATINE REGION

Quadrate

Ectopterygold

Endopteryguld

Metopterygoid

Palatine

MANDIBULAR REGION

MaXillary

Premaxilldry

Dentary

Articular

Angular

25 30 35

-----------

-- - ----- +----_f_

Standard length (mml

10 20

:.:.:..>~::~.~ ..'..'.~:':':":':':~-:. ~t~~~~i - - - - - - - - - ----- ----------- ..................... ---------------

5

CRANIUM

Exoccipital

Basioccipital

Sphenotic

Eplotlc

PterOltC

Parasphenoid

Frontal

Nasal

Vomer

Supraoccipital

P"rietal

Lateral ethmoid

Lachrymal

Circumorbllal 2

Ctrcumorbnal 3

Element

APPENDICULAR REGION

Clelthrum

Coracoid

Supracle,thrum

Posl-temporal

Posl-ciellhrum (ventral}

Posl-cleilhrum (dorsal)

Pelvic

Scapula

Proximal radials IpeCloral1

HYOID REGION

Ceratohyal

SymplectIC

Hyomand\bular

Opercular

Preopercular

Subopercular

lnteropercular

Urohyal

Epihyal

BRANCHIAL REGION

Pharyngobranchlal teeth

(4th arch)

CeralObranchlal (lsI arch)

CeralObranchial (2nd arch)

Ceratobranchtal IJrd arch)

Ceratobranchlal (4th arch)

CeralObranchlal (5th arch}

Ceratobranchlal gill r<'lkers

(Jstarch)

Ceratobranchial gill rakers

(2nd arch)

Ceratobranchlat gill rakers

(3rd arch)

Eplbranchlal (1st arch)

Eplbranchral (2nd arch)

Epibranchlal (3rd arch)

Eplbranchlal 14th arch)

Baslbranchlals

Eplbranchlal gill rakers

(1st arch)

Pharyngobranc~lial teeth

13rd archl

Hypobranchial (1st arch)

Hypobranchial (2nd arch)

Hypobranchial (3rd arch)

Figure IO.-Ossification of major bones in Hexagrammos decagrammus. Symbols as in Figure 2.

19
Table S.-Development of meristic structures of Hexagrammos decagrammus. Specimens between dashed lines are undergoing notochord nexion. The first observation of counl

within adull range is underlined.

Fins

Partial Complete First Second Anal Pectoral Pelvic Secondary Principal Principal Secondary

Standard

length

(mm)

12.0

12.1

12.5

12.5

12.7

13.2

14.6

14.6

Vertebrae'

Precaudal

Partial Complete

Caudal Dorsal

Caudal

-------------- BranchiUpper Lower ostegal

rays

3

2

3

1

2

4

5

Gill rakers

Upper Lower

2

15.6 4 5 6 2

16.0 3 3 6 3

16.8 16 6 31 13 7 .2 6 5

17.0 15 6 31 12 6 8 6 4

17.4 15 6 31 10 7 9 6 6

17.8 14 7 31 14 7 9 6 4

17.9 13 8 32 15 7 9 6 5

-------------------------------------------------------------------------------------------------------------------------------- 18.4 5 17 29 damaged 9 17 1 7 9 1 6 damaged

19.4 21 24 10 19 4 7 9 3 6 7

19.4 21 2 31 21 18 4 7 9 3 6 8

20.2 21 35 19 18 4 7 9 3 6 8

20.4 22 34 15 22 19 1,3 5 7 9 4 6 8

20.6 21 35 21 22 19 1,3 5 7 9 4 6 8

20.9 21 35 21 21 19 1,3 6 7 9 5 6 8

21.0 21 34 13 21 24 19 1,3 7 7 9 6 6 9

22.2 21 35 24 19 1,4 7 7 9 9 6 9

22.5 21 35 22 23 19 1,4 6 7 9 5 6 9

23.8 21 35 18 23 24 18 1,4 8 7 9 7 6 9

23.8 21 35 18 23 25 19 1,4 8 7 9 8 6 9

24.6 21 35 21 24 24 19 .!2 9 7 9 10 6 9

25.6 21 35 21 25 25 19 1,5 10 7 9 10 6 9

'Vertebrae in hexagrammids begin ossification as dorsal and ventral saddle-shaped pieces of bone which join each other laterally to form rings that further ossify to attain their definitive shape. Vertebrae were considered "partial" if ossification had begun. but the dorsal and ventral sections had not fused, after which a vertebra was considered "complete."

superficial trunk pigment. The superficial trunk pigment ventral to the midline is heavy throughout development, relative

to the other species. The isthmus is pigmented along its length

and there is some pigment on the dorsal surface of the tip of

the notochord. At about 13 mm, postanal ventral midline pigment is seen as a row of melanophores starting near the origin

of the anal fin, with more melanophores added posteriorly as

the fish grow. Some pigment spots are also added at the base

of the incipient caudal fin rays. The lateral body surface is

rather heavily pigmented superficially. By 18 mm, the postanal

midline melanophores extend from the anus onto the caudal

peduncle, and the proximal halves of the caudal fin rays are

heavily pigmented. We found two forms of H. decagrammus

larvae depending on the degree of contraction of the melanophores, particularly those of the superficial lateral series and

of the postanal ventral midline series. On some individuals

these are quite expanded giving the larva a dark cast and a

smudgy appearance at low magnification. On other individuals

these melanophores appear much more discrete with unpigmented areas between. Sometimes both types of larvae were

found in the same sample, so the differences do not seem

related to time or area of capture or handling of the sample.

This type of variation was not seen on the other three species

considered here.

20

Hexagrammos lagocephalus (Rock Greenling)

Figures 6, 11, and 12

There is some confusion concerning the taxonomy of this

greenling, which occurs from California to Japan (Quast

1964). Quast (1960) synonomized H. superciliosus, the eastern

form, with H. lagocephalus, the western form. However Harris and Hartt (1977) reported two forms of rock greenling in

bays of Kodiak Island, Alaska, both of which they called H.

lagocephalus. Miller and Lea (1972) considered the rock greenling off California distinct from that found to the west and

used the name H. superciliosus for it following a personal

communication from Hubbs and Follett. If there were one species of rock greenling it would be by far the widest ranging species in the genus. Gorbunova (1962) described larvae as H.

lagocephalus which were collected from the Andreanof Islands

west of northern Japan. These larvae are distinct from those of

H. lagocephalus described here, that were collected primarily

from the Kodiak region, in that they have more intense pigment ventrally on the caudal peduncle and the ventral midline

pigment does not extend forward to the developing anal fin.

No such larvae were found in our samples, taken mainly from

east of long. 180°. We will use the name H. lagocephalus for

the larvae we describe, with the understanding that if two spe-
, ..;:<..,

------

.. -:~

----~

• #,. ~. : ....'" ~~ ~::'''' -:... ...¥ '~. 't"

c

o

E

B

A

D 16 8 mm, E. 28.0 mm. B 11 2 mm, C. 14.5 mm, . . ace hollis: A. 8.5 mm, . . f Hexagrammos lag P Figure 11.-Larvae 0

21
CAUDAL REGION

Urostyle

Uroneural

PALATINE REGION

Quadrate

Ectopterygold

Endopteryqold

MelOptNygold

Palatine

MANDIBULAH REGION

MaXillary

Premaxillary

Uentary

A(llcula,

Angular

25 30 35

Standard length (mm I

5 10 20

LatE~Tal ethmoid

Lachrymal

C,rcumorbital2

C,rcumorbital3

Element

APPENDICULAR REGION

Cleithrum

Coracoid

Supracleithrufll

Post-temporal

Post-cle'thrum (ventral)

Post·c1eithrum (dorsal)

Pelvic

Scapula

Proximal radials (pectoral)

BRANCHIAL REGION

Pharyngobranchlal teeth

(4th archl

Ceratobranchlal (1st arch)

Ceratobranch ial (2nd arch)

CeralObranchial (3rd archl

Cer<Jtobranchial (4th archl

Ceratobranch,al (5th arch)

Ceratobranch,al gill rakers

(1st arch}

CeralObranchial gill rilkers

(2nd arch I

C('ralObranch,al gill rilkers

(3rd arch)

Epibranchial \lst arch)

Epibranchlal (2nd arch)

Epibranch,al (3ro arch)

Epibranchldl (4th arch)

Basibranchials

Ep,branchlal gill rakers

(1st arch}

Pharyngobranch,al n,eth

(3rd arch)

Hypobranchial (lst arch]

Hypobrdnchial (2nd arch]

Hypobranchial (3rd arch)

HYOID REGION

Ceratohyal

Symplectic

Hyomandibul(lr

Opercular

Pre0percular

Subop"rcular

Int~ropercular

Urohya!

Epihyal

CRANIUM

[=xoCClp,tal

Ba"ucupital

SphenotiC

Epiotic

PterotlC

Parasphrnoid

Fruntal

Figure l2.-0ssification of major bones in Hexagrammos lagocephalus. Symbols as in Figure 2.

22
Table 9.-J)evelopmenl of meristic Slructures of Hexagrammos lagocephalus. Specimens between dashed lines are undergoing notochord nexion. The first observation of count

within adull range is underlined.

'Vertebrae in hexagrammids begin ossification as dorsal and ventral saddle-shaped pieces of bone which join each otherlaterally to form rings that further ossify to altain their definitive shape. Vertebrae were considered "partial" if ossification had begun, but the dorsal and ventral sections had not fused, after which a vertebra was considered "complete."

13.1 16 4 30 10 6 7 6 4

13.4 13 5 33 10 6 7 6 5

14.0 2 12 6 7 6 6

14.1 2 5 6 5 4

15.3 15 6 31 18 18 16 7 10 6 6

15.5 15 5 31 14 16 14 7 10 6 6

Gill rakers

Upper Lower

2

2

2

4

5

5

Branchiostegal

rays

Lower

4

6

Caudal

3

5

Upper

Secondary Principal Principal Secondary

Fins

Hexagrammos octogrammus (Masked Greenling)

Figures 6, 13, and 14

This is the most common greenling in the Bering Sea and its

geographic distribution extends south from there to off northern Japan in the west and to off northern British Columbia in

the east (Rutenberg 1962; Hart 1973). It is the smallest member

of the genus; Gorbunova (1962) described the early life history

stages of this species. Comparable stages of development ofH.

octogrammus are attained at a slightly smaller size than the

other species in the genus, although Gorbunova (1962) noted

that specimens from the northern part of the range are larger

at equivalent stages of development than those from the south.

The smallest specimens we examined from near Kodiak Island,

Alaska, were 7.0 mm.

Larvae of H. oClogrammus are the most heavily pigmented

larvae in the genus. The postanal ventral midline is pigmented

along its entire length throughout development. The individual

pigment spots in the line tend to touch each other making a

continuous straight line. The lateral aspect of the trunk becomes densely pigmented during development, as it does in the

other members of the genus. The isthmus is pigmented with

about 10 spots making a "V." The melanophores are unevenly

spaced and the anteriormost and posteriormost tend to be

larger than the others. Pigment is present on the notochord tip

and the internal surface of the pectoral fin base is heavily pigmented. The pigment that covers the midbrain and hindbrain

tends to be continuous across the dorsal midline.

Vertebrae'

9.9

10.7

11.0

Il.l

11.2

12.8

12.9

Standard -------------

length Precaudal Caudal Dorsal

(mm) Partial Complete Partial Complete First Second Anal Pectoral Pelvic

----------------------------------------------------------------------------------------------------------_.--------------------- 16.3 20 32 2 17 21 18 4 7 10 4 6 7

16.6 15 5 32 I 20 17 15 4 7 10 3 6 6

16.8 21 24 8 22 22 18 6 7 10 5 6 7

17.0 20 2 32 20 22 19 6 7 10 6 6 7

28.0 20 33 20 23 23 19 1,5 18 7 10 16 6 2 9

cies are again recognized these larvae would be those of H.

superciliosus.

Gorbunova (1962) described as H. decagrammus larvae that

we believe to be H. lagocephalus; we will describe them more

fully here. Larvae of H. lagocephalus are moderately pigmented with respect to other members of the genus. Except at

its anterior and posterior extremes, the postanal ventral midline is pigmented throughout development, and the pigment is

particularly dense along the caudal peduncle. The pigment

spots remain distinct, not touching each other. They are

uneven in size and spacing and thus create an irregular line.

The ventral part of the superficial lateral trunk pigment appears darker than the dorsal part except posteriorly where the

parts seem equally dark. The isthmus has about 10 evenly sized

and spaced pigment spots in fish > 9 mm that create a "V"

pointed anteriorly. The gular area has a few pigment spots

also. The pigment covering the dorsal surface of the midbrain

and hindbrain tends not to cross the dorsal midline, thus leaving a clear area between the brain hemispheres. Larvae of H.

lagocephalus are slightly deeper bodied both at the pectoral fin

base and at the caudal peduncle than other species in the

genus. Since H. lagocephalus larvae larger than 20 mm were

rare in our extensive plankton and neuston collections from

the major part of the species range, this species may become

demersal at a smaller size than other species of the genus which

were present primarily in the neuston samples at sizes up to

40-50 mm.

23
A

B .... 0. :...

. ....

c

o

E

~""'J~'"

F

Figure 13.-Larvae of Hexagrammosoctogrammlls: A. 7.0 mm, B. 9.7 mm, C. 11.8 mm, O. 15.2 mm, £,20.0 mm, F. 27.8 mm.

24
CAUDAL REGION

Urostyle

Uroneural

25 30 35

- - --~---+-

---- ----

- - - - - -1-----+-

Standard length Imml

20

- - - - t.:::===t::===t::

- - - - .:: .:: .:: .:: :t=====:j::::

5

CRANIUM

Exoccipilal

Basioccipital

Sphenotic;

EPiOtiC

Pteratle

Parasphenoid

Frontal

Nasal

Vomer

Supraoccipital

Parietal

Lateral ethmoid

Lachrymal

Circumorbllal 2

Clrcumorbltal 3

Element

BRANCHIAL REGION

Pharyngobranchial teeth

14th arch I

Ceralobranchial 11 st archl

Ceratobranchlal (2nd archl

Ceralobranchial (3rd archl

Ceralobranchlal (411'1 arch)

Ceralobranchlal (511'1 arch)

Cer3tobranchlal gill rakers

On arch I Ceratobranch,algllt rakers

(2nd arch)

Ceratobranchlal gill rakers

13rd arch)

EPlbranchlal 11 SI arch I Eplbranchlar 12nd arch)

Eplbranchlal13rd arch)

Eplbranchlal 14th arch)

Baslbranchlals

Eplb~anchlal gill rakers

(1st archl

Pharyngobranchlal teelh

(3rd archI

Hypobranchial I 1st arch)

Hypobranchial i2nd arch)

Hypobranchial 13rd arch)

APPENDICULAR REGION

Clellhrum

Coracoid

Supraclcllhrum

Post-temporal

Posl-cre.thrum IvcmraO

Post-c!elthrum Idorsal)

PelvIc

Scapula

PrOlumal radIals (pecloral)

MANDIBULAR REGION

MaXillary

Premaxillary

Dentary

Articular

Angular

PALATINE REGION

Quadrate

EClopterygOld

EndopterygOld

Meloptcrygold

Palatine

HYOID REGION

Ceratohyal

Symplcc!u:

Hyomandibular

Opercular

Preopercular

Subopercutar

Interopercular

Urohyal

Epihyal

Figure 14.-0ssification of major bones in Hexagrammos oClogrammus. Symbols as in Figure 2.

25
Table lO.-Development of meristic structures of Hexagrammos oClOgrammus. Specimens between dashed lines are undergoing notochord nexion. The first observalion of count

within adult range is underlined.

Fins

Partial Complete First Second Anal Pectoral Pelvic Secondary Principal Principal Secondary

Standard

length

(mm)

8.0

8.2

8.5

9.0

9.5

9.8

10.1

11.5

11.9

Vertebrae'

Precaudal

Partial Complete

Caudal Dorsal Upper

Caudal

Lower Branchiostegal

rays

I

I

2

3

3

I

Gill rakers

Upper Lower

12.0 5 2

12.5 9 22 9 6 6 5 3

13.1 13 30 9 4 4 5 3

13.4 5 13 28 2 10 6 6 6 4

14.0 19 4 28 15 2 7 8 6 6

14.0 18 6 25 12 7 8 6 6

14.1 18 6 25 II 7 8 6 6

14.9 18 5 28 15 2 7 8 2 6 8

-------------------------------------------------------------------------------------------------------------------------------_. 16.0 18 32 13 2 7 8 2 6 8

16.5 18 33 17 4 7 8 4 6 8

17.3 19 33 13 21 17 4 7 8 4 6 9

17.7 19 33 21 23 1'1 6 7 8 5 6 9

18.0 18 34 23 24 18 7 7 8 7 6 9

18.0 18 34 24 25 19 8 7 8 7 6 9

19.0 19 33 15 23 22 19 8 7 8 7 6 8

19.0 18 34 15 23 24 19 9 7 8 7 6 8

19.2 18 33 12 24 24 19 8 7 8 7 6 8

20.4 18 34 16 24 25 19 1,2 8 7 8 8 6 2 9

21.0 18 34 17 24 25 18 1,4 12 7 8 10 6 I 9

22.8 18 33 18 23 25 18 .!..2. 14 7 8 12 6 2 10

23.0 18 34 17 23 25 18 1,5 14 7 8 12 6 2 9

25.0 18 34 18 24 26 18 1,5 15 7 8 12 6 2 9

17.0 18 34 18 24 25 19 1,5 16 7 8 14 6 3 \I

29.5 19 33 20 22 24 19 1,5 16 7 8 15 6 3 9

35.0 19 34 19 24 24 19 1,5 17 7 8 16 6 3 II

42.0 18 33 19 23 25 18 1,5 17 7 8 15 6 3 9

45.0 18 33 19 23 24 19 1,5 18 7 8 15 6 4 10

'Vertebrae in hexagrammids begin ossification as dorsal and ventral saddle-shaped pieces of bone which join each other laterally to form rings that further ossify to attain their definitive shape. Vertebrae were considered "partial" if ossification had begun, but the dorsal and ventral sections had not fused, after which a vertebra was considered "complete."

Pleurogrammus monopterygius

(Atka Mackerel, Hokke)

Figures 15 and 16, Appendix Figures 1-10

Following Quast (1960) only one species of Pleurogrammus

is recognized (P. monopterygius) although specimens from the

northwestern Pacific are often considered a separate species

(P. azonus) (Rutenberg 1962). This species occurs in waters

around the Pacific rim north of about lat. 35 0 • It is fished

primarily by the Republic of Korea, Japan, and the U.S.S.R.;

in 1980 the catch in the United States fishery conservation zone

was 33,387 t (U.S. Department of Commerce 1981). In Japan

the annual catch varies from about 80 to 180 thousand t (Yusa

et al. 1977). In contrast to the rest of the hexagrammines, this

is a schooling pelagic fish that is reported to migrate to rocky

shore areas to spawn. Spawning is reported off the Aleutian

Islands in early summer (Gorbunova 1962), and off Hokkaido,

26

Japan, in the fall (Yusa et al. 1977). The larvae and juveniles

are epipelagic and are collected up to 925 km from the coast

(Kobayashi 1958). Quast (1960) considered P. monopterygius

paedomorphic and the pelagic habits of the adults can be

thought of as retentions of the prejuvenile habits seen in other

hexagrammines.

Early life history stages of Pleurogrammus under both specific names (P. azonus and P. monopterygius) have heen

described and illustrated several times by Japanese and Soviet

authors from reared and wild caught material (Kobayashi

1958; Gorbunova 1962; Hattori 1964; Yusa 1967). Gorbunova

(1962) compared larvae she considered to belong to the two

species but did not report any distinguishing features of structure or pigmentation. They were separated chiefly by location

of capture, with P. azonus larvae found west of about long.

l50 0 E and P. monopterygius east of there. The larvae are similar to those of Hexagrammos spp. and can be distinguished
A

B

c

o

.~-~..~;.' .~,:, -,;.

" " , ., '. >

.: ~.'

.: !": :'<>,'

"' . .' .., .". :: .,. .' "

....... '.~ ...'.

- , ..

';",' .: . ';..t ",.;..-.' ';:.--"."';.-~---=-- .:. ' --: .. '

E

.'.... . • , ". '.0 'oJ: .' .. ; •.• .• :; ;; .' . .; .: •

",:." ..

F . <•.

:: ".....

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

F;g'" ",_"'_" " PI.""~"",, .""",,,,,,, A, 9,' mm, B, ",6 mm, C, " .. mm, 0, " .. mm, E, ",,5 mm, F, >S,' mm,

27
5 Element

CRANIUM

Exoccipital

Basioccipital

Sphenotic

Epiotic

Ptero!IC

Parasphenoid

Frontal

Nasal

Vomer

Supraoccipital

Parietal

Lateral ethmoid

Lachrymal

Clrcumorbi!al 2

Clrcumorbltal3

MANDIBULAR REGION

Maxillary

PremaxIllary

Dentary

Articular

Angular

PALATINE REGION

Quadrate

Ectopterygoid

Endopterygold

Me!opterygoid

Palatine

HYOID REGION

Ceratohyal

Symplectic

Hyomandlbular

Opercular

PreoJ)f"rcular

Subopercular

Interopercular

Urohyal

Epihyal

BRANCHIAL REGION

Pharyngobranchlal teeth

14th arch)

Ceratobranchlal 11st arch}

Ceratobranchlal (2nd arch}

Ceratobranl:hla\ (3rd arch)

Ceratobranchlal (4th arch)

Ceratobranchial (5th arch)

Ceratobranchlal gill rakers

(lstarch)

CerJtobranchlal gill rakers

(2nd arch)

Ceratobranchial gill r"kcrs

(3rd arch)

Eplbranchlal (1st drch)

Epibranchlal (2nd Jrch)

Eplbranchlal (3rd arch)

Epibranchial 14th arch!

Baslbranchials

Eplbranchlalg,lI rakC!rs

11starch)

Pharyngobranchlal t~flth

(3rd arch)

HYP0branchiai (1st arch)

Hypobranchial (2nd arch I

Hypobranchiol (3rd arch)

APPENDICULAR REGION

Clelthrurn

Coracoid

$upraclelthrum

Post-temporal

Post·cle thrum (ventral)

Post-clelthrum tdorsal)

PelVIC

SC<lpula

PrOXImal radials (pectoral)

CAUDAL REGION

Urostyle

Uroneural

10

Standard length (mm I

20 25 30 35

Figure 16.-0ssification of major bones in Pleurogrammus mOflopteryg;us. Symbols as in Figure 2.

from them mainly on the basis of pigment patterns. The larvae

described here were collected in plankton and neuston nets in

the Gulf of Alaska and the eastern Bering Sea. They were identified on the basis of earlier published descriptions and pigment patterns which could be traced back to small larvae from

larger specimens which had distinguishing meristic characters.

Pigmentation-Yolk-sac larvae have a melanophore pattern

which is seen in larger larvae with only slight changes. The

forebrain, midbrain, and hindbrain are covered with large stellate melanophores, and a patch made up of several melanophores covers the upper preopercular region. In contrast to

Hexagrammos larvae, the snout is unpigmented. A heavy line

of melanophores connects to the midbrain pigment and runs

along the dorsal midline from the nape to just anterior to the

tip of the notochord. At the nape there are a few additional

superficial melanophores just lateral to the dorsal midline pig28

ment. Laterally there is a line of melanophores, mainly internal, just dorsal and ventral to the notochord. The dorsal line

originates above and just anterior to the level of the anus, and

the ventral line originates a few myomeres posterior to the

anus. Both lines terminate anterior to the tip of the notochord.

Ventrally, along the midline, a line of small distinct melanophores originates about 15 myomeres posterior to the anus and

the melanophores increase in size and become more closely

spaced until they terminate as a solid line just anterior to the

notochord tip. In the area of the caudal peduncle, superficial

lateral melanophores form a relatively heavily pigmented area.

The dorsolateral surface of the gut cavity is heavily pigmented

with stellate melanophores. As the larvae grow these melanophores cover more of the peritoneum, until by about 20 mm it

is totally covered except along the ventral midline. Also as the

larvae grow to about 14 mm a few small melanophores lie
around the posterioventral rim of the orbit and a few are

added to the isthmus. The anterior part of the ventral midline

pigment line becomes difficult to see as it is covered with flesh.

By 20 mm the body is becoming densely covered with superficial melanophores that form a wide stripe over most of the

lateral body surface by 25 mm. The dorsal midline pigment is

more intense, as is the terminus of the lateral pigment at the

base of the caudal fin. The fin folds, fins, and jaws are unpigmented throughout larval development.

Morphology-Morphometric measurements were taken on

84 larvae from 9.8 to 26.5 mm. During this length interval the

body shape is typical of that of other hexagrammine larvae:

They have blunt heads (head length increases from 18 to 25070

SL), thin bodies (body depth increases from 13 to 19% SL),

large eyes (eye diameter decreases from 56 to 39% HL), and

short snouts (snout length increases from 9 to 16% HL). Preanal length increases from 33 to 50% SL. The notochord flexes

between 14 and 19 mm. The major differences between body

shape of P. monopterygius larvae and that of other hexagrammines are the slightly larger eye (by 5-10% head length) and

the shorter snout (by about 2% head length), the shallower

body depth at 15 to 25 mm and the larger size at which the increase in total length relative to standard length occurs (by 2-4

mm SL).

Developmental Osteology (Table II)-A series of 43 larvae

from 9.7 to 28.1 mm was cleared and stained to trace development of osteological features. Larvae of P. monopterygius are

larger than other hexagrammine larvae at time of formation of

most features. Relative to the sequence of development of

meristic features seen in other hexagrammines, in P. monopterygius the median fins develop earlier and the vertebrae and

pelvic fins develop later. Branchiostegal rays form at 11.1-15.1

mm and principal caudal rays form at 15.1-16.2 mm, although

the uppermost principal ray still appears to be epaxial even in

Table n.-Development of meristic slructures of Pleurogrammus monopterygius. Specimens between dashed lines are undergoing notochord nexion. The first observation of

count within adull range is underlined.

Fins

Vertebrae'

Partial Complete Partial Complete First Second Anal Pectoral Pelvic Secondary Principal Principal Secondary

Gill rakers

Upper Lower

Branchiostegal

rays

Lower

Caudal

Dorsal Upper

Standard --------------

length Precaudal Caudal

(mm)

11.1

11.1

11.2

12.1

12.2

12.5

13.1

13.3

13.6

I

I

4

4

4

4

4

5

14.0 4

14.1 5

14.3 5

15.1 4 6 5

15.1 6 9 6

15.1 4 6 '6 16.2 14 7 II 6

16.2 15 7 II 6

16.3 14 7 II 6

17.0 15 I '7 II 1 6

17.3 16 I 7 II I 6 3

17.9 16 2 7 II I 6 2

18.2 14 3 7 II 2 6 3

-------------------------------------------------------------------------------------------------------------------------------- 19.2 7 I 17 4 7 II 3 6 5

19.3 8 I 18 2 7 II 2 6 5

19.6 6 I 12 17 18 4 7 11 3 6 5

20.0 7 2 I 12 13 18 2 7 II 3 6 6

20.9 5 2 I 13 13 19 5 7 II 3 6 5

21.0 II 6 I 8 23 21 21 5 7 II 4 6 7

21.5 II 8 1 5 21 21 20 6 7 11 5 6 6

21.9 12 7 I 10 22 21 21 5 7 II 4 6 6

22.1 7 8 1 12 25 22 20 7 7 II 5 6 6

23.7 17 9 6 I 19 28 25 22 1.3 9 7 II 8 6 9

23.7 17 10 5 I 21 27 26 24 1.3 8 7 II 7 6 10

24.2 14 13 33 I 21 26 24 23 1,3 8 7 11 7 6 8

24.3 13 14 32 I 22 26 25 24 1.3 9 7 II 8 6 9

28.1 7 19 27 8 23 26 25 25 1.5 14 7 11 12 6 12

'Vertebrae in hexagrammids begin ossification as dorsal and ventral saddle-shaped pieces of bone which join each other laterally to form rings that further oss;fy to attain their definitive shape. Vertebrae were considered "partial" if ossification had begun, but the dorsal and ventral sections had not fused, after which a vertebra was considered "complete."

'Apparently the posteriormost upper secondary caudal fin ray, that is first present in this specimen, changes position to become the dorsalmost (eighth) principal caudal fin ray

later in development.

29
the 28.3 mm specimen. The pectoral fin rays form next at

16.2-23.7 mm. The dorsal and anal fin rays form between 20

and 24 mm. The pelvic fins are the last fins to form at between

24 and 28 mm. The urostyle ossifies at 16.2 mm, the abdominal vertebrae start to form at 20 mm, and neither the al::dominal nor caudal vertebrae are all fully ossified by 28.3 mm, the

largest specimen of the series. First arch gill rakers start forming at 16.2 mm and continue to be added throughout the series

examined.

On the smallest larvae stained, several bones of the skull

(pterotic, exoccipital, sphenotic), suspensorium, and branchial

area are present as cartilage. Most of the neural and hemal

spines are cartilage, and there is an extended cartilagenous

posterior coracoid process. During flexion most of the skeletal

elements start to ossify and the hypurals form as cartilage. By

the end of flexion, the neural and hemal spines have all ossified except for the last few. By 22 mm the bones of the jaws

and those of the opercular region have attained their adult

shapes. By 28 mm most of the bones of the head have started

to ossify and there are a few teeth in the jaws. In other hexagrammines most bones have already attained their adult shapes

by this size. The appendicular skeleton, except for the proximal pectoral radials, is mostly ossified. Dorsal and anal fin

pterygiophores are present as cartilage. The epurals are present

as cartilage; the rest of the caudal skeleton, including a pair of

small uroneurals, is ossified. A foramen is present in both the

dorsal and ventral hypural plates, indicating that each is composed of two elements (the upper of hypurals 3 and 4, the

lower of the parhypural and hypurals I and 2). The uppermost

dorsal principal caudal ray develops first as the posteriormost

dorsal secondary caudal ray that moves caudally across the upturned tip of the notochord to become supported by the dorsal

hypural plate.

DISCUSSION

Recent studies have demonstrated the efficacy of using larval fishes to elucidate relationships among several taxa and

categories (Johnson 1974; Okiyama and Ueyanagi 1978; Kendall1979). Among the Scorpaeniformes current studies are using larval characters of cottids to investigate relationships

(Richardson 1981; Washington 1981; Richardson'). Although

the systematics of the Scorpaeniformes need attention at every

level, there appear to be three major suborders: The Hexagrammoidei which are derived from the Cottoidei, which in

turn are derived from the Scorpaenoidei (Quast 1965). The interpretation of larval characters discussed below indicates that

the hexagrammoid line arose from the cottoid line before the

latter had differentiated much from the scorpaenoids. The

most convincing synapomorphy of the Scorpaeniformes is the

posterior extension of the third suborbital bone so that it connects with the preoperculum. Among the hexagrammids under

consideration here, no differences in formation of this feature

were noted: The third suborbital formed late in larval development and gradually extended posteriorly to reach the p,eoperculum during the juvenile stage.

A comparison of larval characters between presumed primitive scorpaenids and cottids and hexagrammids may help

'So L. Richardson, Associate Ichthyologist, Gulf Coast Research Laboratory,

East Beach Drive, Ocean Srrings. MS 39564, rers. commun. November 1981.

30

define the family Hexagrammidae, and determine its relationship to the other major groups of scorpaeniforms. Richardson

(1981) listed presumed plesiomorphic characte,s of cottid larvae (which are assumed to be apomorphic with regard to the

scorpaenoids) to include: Four strong preopercular spines,

relatively deep compact body, presence of a preanal finfold,

rounded snout, short pectoral fin, and a compact gut that

lacks diverticula. Larval cottid group 4 (Richardson 1981),

composed of Hemilepidotus spp. and Scorpaenichthys marmoratus, exhibited the plesiomorphic states of most of these

characters. Sebastes seems to be representative of a generalized

scorpaenoid. States of these characters as well as other features observable in the larvae that might help interpret relationships among these fishes are discussed below (Table 12).

Preopercular spines-Larvae of Oxylebius pictus, Zaniolepis

sp., and Ophiodon elongatus possess preopercular spines, and

other armature, but none is present in larvae of Hexagrammos

spp. and Pleurogrammus monopterygius. In Oxylebius pictus

four preopercular spines, similar to those seen in S. marmoratus and Hemilepidotus spp. (Richardson 1981), develop by the

end of flexion. A fifth spine is added ventrally late in larval

development (12-13 mm). In Zaniolepis sp. the preopercular

spines are less pronounced, but up to seven develop by the late

larval period. In Ophiodon elongatus larvae the preopercular

margin is smooth until well after flexion when first two, then

two more small, blunt spines develop. Sebastes larvae have 2-5

preopercular spines that are generally more robust than those

on the other larvae considered here (Moser et al. 1977).

Body shape-So marmoratus and Hemilepidotus spp. share

the presumed plesiomorphic condition of a relatively deep

body (Richardson 1981). In these larvae body depth increases

with development from 15-19070 SL in preflexion larvae to

32-35 % in postflexion larvae (Richardson and Washington

1980). Larvae of Oxylebius pictus are deeper bodied during

preflexion stages but about equal to these cottids after flexion.

The other species described here have body depths from 13 to

18% SL during preflexion stages, but the depth only increases

to a maximum of 25070 in postflexion larvae of H. lagocephaIus, whereas in the other species it stays < 22%. Zaniolepis sp.

larvae seem equally slender bodied, although too few specimens were available for meaningful measurements. Sebastes

larvae are quite deep bodied (> 20% SL at flexion) (Moser et

al. 1977).

Preanal finfold-A small preanal finfold is present in early

preflexion larvae of O. pictus. It remains visible in Zaniolepis

sp. larvae until shortly after flexion. In Ophiodon elongatus

larvae it is present throughout the larval period. In Hexagrammos sp. and P. monopterygius larvae it is present until the early postflexion stage. The preanal finfold is a presumed primitive character in cottid larvae, and is absent in Sebastes larvae

(Table 12).

Snout shape-A basically rounded snout (8-28% head

length) is present in larvae of all the taxa described here except

0. elongatus (25-36% head length) which has a pointed snout

starting in the early flexion stage. The snout is rounded in larvae of presumed primitive cottids, and is moderately pointed

in Sebastes larvae (Table 12).

Pectoral fin development-Rays start to develop in the pectoral fin before flexion and shortly after the caudal fin rays

develop but before development of rays in any of the other fins

in all taxa described here. Pectora! fins reach their adult complements of rays during flexion in Oxylebius pictus and
Table 12.-Characterstates observed among hexagrammid larvae, in relation to theirstatesin larvae ofSebastesspp. (Moseret aI. 1977; Moser and Ahlstrom 1978) and in larvae of

Hemilepidotus spp., a presumed primitive cottid (Richardson and Washington 1980; Richardson 1981).

Character states

Character Sebasles spp. Hemilepidolus spp.

Preopercular spines 3-5 strong spines 4 strong spines

Body depth > 20"70 SL at flexion > 15% SL at flexion

Preanal finfold absent present

Snout shape moderately pointed rounded « 25% head

(>25% head length) length)

Pectoral fin size variable-reaching anus shon

in some

Gut shape compact. not trailing compact, not trailing

Head spines on many bones on few bones

Appendicular skeleton spines on posttemporal reduced to bumps

armature (2) and supracleithrum

(1)

Pelvic fin ray before dorsal and after dorsal and

development sequence anal fins anal fins

Adult numbers of

principal caudal

fin rays

Adult caudal fin

skeleton'

Anal fin spines

Pigment pattern

'HemilepidoluS. pers. obs.

8+7

hypurals I and 2 fused,

hypurals 3 and 4 fused,

hypural 5 present

3 strong

light

6+6

parhypural and hypurals

I and 2 fused, hypurals

3 and 4 fused, hypural

5 absent

no spines

heavy

Observed states

in hexagrammids

3-7 spines

no spines

< 20% SL at flexion

> 20% SL at flexion

present (at least preflexion)

rounded « 25% head length)

pointed (> 25% head length)

shon-not reaching anus

long-reaching anus

compact. not trailing

none

on few bones

spines on posttemporal and

supracleithrum

none

concurrent with dorsal and

anal fins

concurrent with first dorsal.

after second dorsal and

anal fins

7+6

7+7

7+8-10

8+ II

parhypural free from fused

hypurals I and 2

parhypural and hypurals I and

2 fused

hypural 5 present

hypurals 3 and 4 fused

3-4 strong

0-3 weak

heavy

Hexagrammid genera

Oxywbius.Zanwwp~.Ophwdon

Hexagrammos. Pleurogrammus

Ophiodon. Hexagrammos, Pleurogrammus

Oxylebius, Zaniolep~

all

Oxylebius. Zaniolep~, Hexagrammos,

Pleurogrammus

Ophiodon

Ophiodon, Hexagrammos. Pleurogrammus

Oxylebius, Zaniolep~

all

all except Zaniolep~

Zaniolep~

Oxylebius, Zaniolep~

Ophiodon. Hexagrammos. Pleurogrammus

Oxylebius. Zaniolep~

Ophiodon. Hexagrammos,

Pleurogrammus

Oxylebius, Zaniolep~

Ophiodon

Hexagrammos

Pleurogrammus

Ophiodon

Oxylebius, Zaniolepis.

Hexagrammos. Pleurogrammus

Oxylebius

all

Oxylebius, Zaniolepis

Ophiodon. Hexagrammos. Pleurogrammus

all

Zaniolepis sp. but continue to add fin rays until late in the larval period in the other taxa. The pectoral fin is large in O. pictus and Zaniolepis sp. larvae, reaching posteriorly well beyond

the anus in late larvae. In the other taxa, however, the pectoral

fin is small, never reaching the level of the anus. In presumed

primitive cottids the larval pectoral fin is short, and it is variable in length among species of Sebastes (Table 12).

Gut shape-The gut in hexagrammid larvae is compact

without diverticula or a trailing hindgut. The preanal length

varies from 42 to 60% SL, with Ophiodon elongatus having

the longest preanal length (52-60070 SL). The hindgut of Zaniolepis sp. seems slightly enlarged and bulges slightly before flexion is complete. The larval gut is compact in both presumed

primitive cottids and in Sebastes (Table 12).

Appendicular skeletal armature-Sebastes larvae generally

possess numerous spines on the head and on the bones of the

appendicular skeleton (Richardson and Laroche 1979). Some

cottid larvae likewise possess such armature, but it is generally

not as sharp or extensive. In hexagrammid larvae the shoulder

region is unarmed, except in Oxylebius pictus and Zaniolepis

sp. where small spines develop on the posttemporal and on the

suprac1eithrum.

Pelvic fin development-In larvae of O. pictus and Zaniolepis

sp. the pelvic fin bud is first seen during flexion; in Ophiodon

elongatus it is first seen in early postflexion larvae and in Hexa31

grammos spp. and P. monopterygius not until well after flexion. In the latter three genera the pelvic fin does not reach its

adult complement of rays until all other fin rays, except the

secondary caudal rays, are present. In Oxylebius pictus and

Zaniolepis sp. pelvis fin ray counts are complete shortly after

flexion. In Sebastes the pelvis fin develops before the dorsal

and anal fins (Moser et al. 1977). Hexagramminds retain the

presumed plesiomorphic scorpaeniform pelvic fin ray count of

1,5, whearas in cottids the count is reduced in many genera

with 1,3, being the most common number (Richardson and

Washington 1980.).

Principal caudal fin rays-Ahlstrom and Moser (1976) emphasized the stability of principal caudal fin ray counts within

higher categories of fishes. Sebastes has 8+7 principal caudal

fin rays (Moser et al. 1977); the number is reduced to 6+6 in

cottids, with several taxa having even fewer. Oxylebius pictus

and Zaniolepis sp. have 7+6 principal caudal fin rays, Ophiodon elongatus has 7 +7, the count varies among the species of

Hexagrammos from 7+ 8 to 7+ 10, and P. monopterygius has

8+ II. The progression of increase in principal caudal rays

seems to parallel an increase in free-swimming habit as opposed to rest-and-dart behavior seen among other taxa. This

may also be related to a decrease in the use of the pectoral fins

in propulsion, which appears to be of primary importance in

many cottids and Oxylebius pictus.
Caudal fin skeleton-In the hexagrammid taxa there is a

variable number of principal caudal fin rays, and a variable

number of elements in the caudal fin skeleton resulting from

both loss and fusion of elements. One uroneural was present,

as in Sebastes (Moser and Ahlstrom 1978), a reduced condition

compared with the basic perciform number of2 (Gosline 1961)

(Table 13). Apparently this represents a loss of one uroneural

since no evidence of fusion similar to that in Coryphaena

(Potthoff 1980) was seen. Three epurals developed in all taxa

examined here. The parhypural fused to the lower hypurals in

all larvae except Ophiodon elongatus. In those taxa where it

fused, a foramen was seen as the ventral hypural plate ossified.

Hypurals I and 2 fused in all taxa examined, as occurs in

Sebastes (Moser and Ahlstrom 1978). Thus in Oxylebius picIUS, Zaniolepis sp., Hexagrammos spp., and P. monopterygius

there is a ventral hypural plate composed of the parhypural

and hypurals I and 2. Hypural 5 was seen only in O. pictus; it

is characteristic of the basic perciform pattern (Gosline 1961)

and is present in Sebastes (Moser and Ahlstrom 1978). Hypurals 3 and 4 are fused to form a dorsal hypural plate in all

taxa examined here as they are in Sebastes (Moser and Ahlstrom 1978). During development, hypural fusion was usually

indicated by separate centers of ossification or gaps which later

filled in with bone. Two autogenous hemal spines are present

in all taxa examined, as they are in Sebastes (Moser and Ahlstrom 1978) and in basic perciforms (Gosline 1961). The urostyle was the first bone to ossify in the caudal region and there

was no indication of it being composed of more than one element. On its anteriodorsal surface a pair of small spines

developed as in Coryphaena (Potthoff 1980, fig. 21). A modified neural arch without a neural spine developed on the centrum anterior to the urostyle. This appeared to be composed of

two serial sections; the anterior one developed in cartilage between the last and next-to-Iast full centrum. These two sections

remained separate throughout the largest material examined of

O. piCIUS and Ophiodon elongatus. In P. monopterygius and

Hexagrammos spp. there was generally only one section, but

two, or indications of a fusion of two, were seen in some

specimens.

Anal fin spines-Sebastes has three strong anal spines

(Moser et al. 1977), while cottids have only soft rays in the anal

fin (Richardson and Washington 1980). Oxylebius pictus and

Zaniolepis sp. have 3 to 4 strong anal spines, but the rest of the

taxa described here have a variable number (0-3) of spines that

are so weak that it is difficult to distinguish between spines and

soft ray,. The dorsal fin spines in these taxa are also weak, particularly in Hexagrammos spp. and P. monopterygius.

Pigment patterns-Larvae of Sebastes are generally lightly

pigmented until well after flexion, except in some species with

heavily pigmented pectoral fins (Moser et al. 1977). Cottid larvae are variable in pigment, but the presumed primitive cottid,

Scorpaenichthys marmoratus, has a heavily pigmented larva

(Richardson 1981). All hexagrammid larvae develop heavy pigmentation over much of the body. This is presumably related

to their epipelagic prejuvenile stage, when similar pigment is

seen in other fish that have such a stage. In life these fish have

iridescent dark green to blue upper bodies and silvery lower

bodies, but this pattern disappears on preservation. Since this

pigment pattern is highly adaptive for fish in this habitat, it

may be of limited value in interpreting relationships, as it is

subject to convergence. Hexagrammos spp. and P. monopterygius are the most heavily pigmented hexagrammids, and

among the species of Hexagrammos a progression from less to

more pigment is: H. slelleri, H. decagrammus, H. {agocephaIus, and H. octogrammus. The highly pigmented pectoral fins

of O. pictus and Zaniolepis sp., are unusual but not unique

among scorpaeniforms. Similarly pigmented pectoral fins are

seen in some Sebastes (Moser et al. 1977), Anoplopoma fimbria (Ahlstrom and Stevens 1976), and the psychrolutid cottids

(Richardson 1981).

In summary, no single larval character was found which

clearly indicated that the hexagrammids are a monophyletic

group. Also, although hexagrammid larvae can be distinguished from Sebastes and cottid larvae on the basis of several

characters, little additional evidence on the relationships

among these groups was provided. For example, the pattern of

fusion and loss of bones in the caudal skeleton showed that all

conditions seen in the hexagrammids and Hemilepidotus could

Table n.-Major components of the caudal fin skeleton in hexagrammids, Hemilepidotlls, and Sebastes compared with the basic perciform pallern.

" + " represents presence of un element, "0" its absence. Braces indicate fusion of elements. Three epurals and an autogenous hemal spine on each of the

two vertebrae immediately anterior to the urostyle are present in all listed taxa.

Basic perciform

Component pattern l Sebastes' Ophiodon Oxylebius Zaniolepis Hemilepidotus' Hexagrammos Pleurogrammlls

Uroneurall + + + + + + + +

Uroneural2 + 0 0 0 0 0 0 0

Parhypural + + +

} + + + + +

Hypurall +

) + +

Hypural2 t

Hypural3 +

} + + + + + + +

Hypural4 +

Hypural5 + + 0 + 0 0 0 0

Principal

caudal fin

rays

dorsal 9 8 7 7 7 6 7 8

ventral 8 7 7 6 6 6 8-10 II

'Gosline (1%1).

'Moser and Ahlstrom (1978).

'Pers.obs.

32
be derived from that of Sebastes, which in turn could be derived from the basic perciform pattern. However, the pattern

in Hemilepidotus was identical to that in Hexagrammos and

Pleurogrammus, while it appeared that the patterns in Ophiodon and Oxylebius were each derived from the Sebastes pattern independently. The need for analysis of more characters

among more members of the cottids and scorpaenids is indicated.

Among the hexagrammids, three groups of taxa were

demonstrated by larval morphology. Analysis of the phyletic

relationships among these groups of taxa must await a thorough

examination of the adults. Nevertheless, based on larval appearance, Oxylebius and Zaniolepis are quite similar as are

Hexagrammos and Pleurogrammus, while Ophiodon shares

few characters in common with either of these groups.

ACKNOWLEDGMENTS

We express our appreciation to the following people who

assisted us in preparing this paper: David Misitano, NWAFC

Mukilteo Laboratory, for rearing specimens of several species

we describe; Kenneth D. Waldron, NWAFC (retired), for preliminary taxonomic work on larval hexagrammids; Jean R.

Dunn and Ann C. Matarese, NWAFC, for helpful discussions;

Bernie Goiney and Jay Clark, NWAFC, for technical assistance in the laboratory; Russell Kappenman and Ralph Mintel,

NWAFC, for computer-related assistance; Sally L. Richardson, Gulf Coast Research Laboratory, for exchange of ideas

and specimens and reviewing the manuscript; J. C. Quast,

NWAFC, for helpful discussions and reviewing the manuscript; Thomas Potthoff for reviewing the manuscript; and H.

G. Moser, SWFC, Gerald E. McGowan, Natural History Museum Los Angeles County, William Watson, Marine Ecological Consultants, Solana Beach, Calif., and Alan Cass, Pacific

Biological Station, Nanaimo, B.C., for loan of specimens.

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132 Hexagrammos stelleri 132 H. octogrammus

128 128

124 124

120 120

116 116 .-

112 112

108 108

104 104

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

132 132 H. decagrammus H. lagocephalus

128 128

£ 124 124 ; 0>

C

.!!! 120 ."" 120

"0

c 116 j~~~ . . 116

'0

c: 112 112 .,

u

:;;

0- 108 108

......

104

1

104

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

132 Ophiodon elongatus 132 Pleurogrammus monopterygius

128 128

124 124

120 120

116 .. 116 . " '.

112 112

108

1

108

.'1' 104· 104

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

Standard length (mm)

Appendix Figure 1.-Totallenglh as a percentage of SL versus SL during development of six species of hexagrammids.

35
30

Hexagrammos stelleri 30

H. octogrammus

28 28

26 26

24

li~• «-~

-<- <' 24 1-«--;--: .. 22 • <, 22

.<

20 , < 20 «

~~

18 j 18

I 16

1 16

I

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

30 H. decagrammus 30

H. lagocephalus

28 28

.;; 26 26

'" {/ c

24 24 I .., ",' '. -0

C

t: 22 22

'0

c: 20 20

"'

"' /; "- 18 18 • «

16 16

,

10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

30 Ophiodon elongatus 30

Pleurogrammus monoptervgius

28 28

< <'

r··~ 26 >c "" ><" ".:-- 26

)( II" " "

24 24

22 . . 22 " " " " 1<

20 20 <I' 18 18

16

1

16

I

0 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

Standard length (mm I

Appendix Figure 2.-Head length as a percentage of SL versus SL during development of six species of hexagrammids.

36
60 Hexagrammos stelleri 60 H. octogrammus

56 56

52 52

48 48

44 44

40 40 '.. 36 36

32 32

0 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

60 H. decagrammus 60 H. lagocephalus

56 56

.c 52 52

0,

c:

48 .. 48

. ' "tJ

44 44

(;

C 40 40

'"

a.. '" 36 36 .~'"

32 32

0 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

60 Ophiodon elongatus 60 Pleurogrammus monopterygius

56 ,;< 56 .. " ....

52 52

....-----,~. . 48 48

44 44

40 40

36 36

32 32

I

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

Standard length (mm)

Appendix Figure 3.-Preanallength as a percentage of SL versus SL during developmenI of six species of hexagrammids.

37
38
12.0

Hexagrammos stelleri 12.0 H. octogrammus

11.2 11.2

10.4 10.4

9.6 9.6

8.8

~_.~C 8.8

r 8.0 ""x " ><

. . . 8.0

,," "" K

7.2 7.2

6.4 6.4

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

12.0 12.0 H. decagrammus H. lagocephalus

11.2 11.2

-5 10.4 10.4 en

" 9.6 9.6

:-

" 8.8 8.8

'0

::: 8.0 8.0

'"

0- 7.2 7.2

6.4 6.4

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

12.0 Ophiodon elongatus 12.0 Pleurogrammus monopterygius

11.2 11.2

10.4 10.4

9.6 9.6

8.8 88

8.0 8.0

7.2 i\ 7.2

r~• n •. ,. 6.4 '-.. 6.4 '.. .,~ .? "., >< "

10 20 30 40 50 60 70 80 0 10 20 60 70 80

Standard length (mm)

Appendix Figure 5.-Body depth at the caudal peduncle as a percentage of SL versus SL during development ofsix species of

hexagrammids.

39
28 Hexagrammos stelleri 28 H. octogrammus

27 27

f\ 26 (\ 26

.. 25 "- 25

. ." .. 24 .~: 24

" 23

'"" 23 ."" 22 22

21 21

I I I !

10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

28 H. decagrammus 28

H. lagocephalus

27 27

-S 26 26

en

c

25 25

-0

c 24

f\~~.~ 24 r\ '0 23 23 c

'"

"-'" 22 22

.. 21 /1

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

28 Ophiodon elongatus 28

Pleurogrammus monopterygius

27 27

26 26

.. 25 25

24 24

23 ... 23 f". ""-

22 22 .". " "-~" "

. . 21 21

10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

Standard length Imm)

Appendix Figure 6.-Snoul to dorsal fin origin length as a percentage of SL versus SL during development of six species of

hexagrammids.

40
38 ] 38

Hexagrammos stelleri H. octogrammus

36 36

34 34

32 32

30

~. 30

28 28

26 26

24 24

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

38 H. decagrammus 38 H. lagocephalus

36 36

-5 34 34

J 0>

C

.!!! 32 32

"0 ./ c 30 30

'0

r~~-- ;:: 28 28

'" . . 0.. 26 26

24 24

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

38 38

Ophiodon elongatus Pleurogrammus monopterygius

36 36

34 34

32 32

30 30

28 28 -'-.. ~~'-- ;-;-.J. I~

., 26 26

24 24

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

Standard length (mm)

Appendix Figure 7.-5nout 10 pelvic fin origin length as a percenlage of 5L versus SL during developmenl of six species of

hexagrammids.

41
68 68 Hexagrammos stelleri H. octogrammus

64 64

60 60

56 56

52 52 .. .. "" "

"" "" .. 48 48 ;? 44 44

40 40

0 10 20 30 40 50 6C 70 80 0 10 20 30 40 50 60 70 80

68 68

H. decagrammus H. lagocephalus

64 64

.I:: 60 60

0,

c

56 56

.t! "0

52 52

'0 " "" ".-

C 48 . .' 48

'" .,." ..

Cl. 44 44

40 40

10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

68 Ophiodon elongatus 68 Pleurogrammus monopterygius

64 64

60 60

56 ~.. . . . .. . 56

. . 52 52 " "" It "

.".. ."

48 48

44 44

40L 40

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

Standard length (mm)

Appendix Figure S.-Snout to anal fin origin length as a percentage of SL versus SL during development ofsix species of hexagrammids.

42
60 Hexagrammos stelleri 60

H. octogrammus

55 55

50 50

45

'\~~ 45

40 ,40 '~ 35 35 ,,,' '."",

,~ 30 "'-'>-, 30 ><"~

25 25

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

60 60

H decagrammus H lagocephalus

55 55

50 '\ 50

<5

0>

c: 45 45

"E

.J::

" 40 40

'0

C 35 35 "

u ';'y" <;

Q. ""'. '; 30 "~ 30

" ::--,

25 25

0 10 20 30 40 50· 60 70 80 0 10 20 30 40 50 60 70 80

60 60

Ophiodon elongatus Pleurogrammus monopterygius

55 55

50 50

45 45

40 40

35 "", 35

30 30

,'"

25 25 '~, ';" !

.~.

, I , I I !

0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

Standard length (mm)

Appendix Figure 9.-Eyediameter as a percentage of head length versus SL during development ofsix species of hexagrammids.

43
0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80

36 H. decagrammus 36 H. lagocephalus

32 32

c

2! 28 28

"0

'"

'"

"" 24 24

'0

c

u'"w 20 '/' 20 ,~

I" /, a.. j 16 16

12 ./ 12

0 10 20 30 40 50 60 70 80 10 20 30

36 Ophiodon elongatus 36 Pleurogrammus monopterygius

32 / 32

" " " 28 ' , 28 '~.

y" ,/'

24 24

20 20 " "":

16 16

12 12 .r

l 8

0 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

Standard length (mm)

Appendix Figure lO.-Snoutlength as a percentage of head length versusSLduring development ofsix species of hexagrammids.

44