22

NOAA Technical Report NMFS 22

Congrid Eels of the Eastern

Pacific and Key to Their

Leptocephali

Solomon N. Raju

February 1985

u.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service
NOAA TECHNICAL REPORTS NMFS

The major responsibilities of the National Marine Fisheries Service (NMFS) are to monitor and assess the abundance and

geographic distrihution of fishery resources, to understand and predict fluctuations in the quantity and distribution of these

resources, and to establish levels for optimum use of the resources. NMFS is also charged with the development and implementation of policies for managing national fishing grounds, development and enforcement of domestic fisheries regulations,

surveillance of foreign fishing off United States coastal waters, and the development and enforcement of international fishery

agreements and policies. NMFS also assists the fishing industry through marketing service and economic analysis programs,

and mortgage insurance and vessel construction subsidies. It collects. analyzes. and publishes statistics on various phases of the

industry.

The NOAA Technical Report NMFS series was established in 1983 to replace two subcategories of the Technical Reports

series: "Special Scientific Report-Fisheries" and "Circular." The series contains the following types of reports: Scientific

investigations thai document long-term continuing programs of NMFS, intensive scientific reports on studies of restricted

scope, papers on applied fishery problems. technical reports of general jntere~t intended 10 aid conservation and management,

reports that review in considerable detail and at a high technical level certain broad areas of research, and technical papers

originating in economics studies and from management investigations.

Copies of NOAA Technical Report NMFS are available free in limited numbers to governmental agencies, both Federal

and State. They are also available in exchange for other scientific and technical publications in the marine sciences. Individual

copies may be obtained from: U.S. Department of Commerce, National Technical Information Service, 5285 Port Royal Road,

Springfield, VA 22 I61
NOAA Technical Report NMFS 22

Congrid Eels of the Eastern

Pacific and ~ey to Their

Leptocephali

Solomon N. Raju

February 1985

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 propriety 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Notes on taxonomy and distribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Taxonomy " .. .. .. .. .. 1

Seasonal distribution and relative abundance 2

Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Identification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Methods of collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Drawings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Key to the congrid leptocephali of the eastern Pacific. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Subfamily Bathymyrinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Ariosoma gilberti ' . . 3

Paraconger californiensis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Paraconger sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Paraconger dentatus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Chiloconger labiatus 8

Chiloconger similis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Subfamily Heterocongrinae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Taenioconger digueti and T. canabus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Gorgasia punctata .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Gorgasia obtusa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Subfamily Congrinae 11

Gnathophis catalinensis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Hildebrandia nitens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Bathycongrus macrurus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Bathycongrus varidens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Literature cited .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Figures

1. Early life history stages ofAriosoma gilberti . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2. Distribution ofAriosoma gilberti ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3. Early life history stages ofParaconger californiensis and larva ofParaconger sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4. Distribution ofParaconger californiensis, Paraconger sp., and P. dentatus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5. Early life history stages of Taenioconger spp., juveniles of T. digueti and T. canabus, and larvae of Gorgasia punctata and G.

obtusa . .. .. .. .. .. . . .. . . .. .. .. .. . .. .. .. .. .. .. 9

6. Distribution of larvae and juveniles of Taenioconger spp., T. digueti, T. canabus, Gorgasia punctata, and G. obtusa . . . . . . . . . . 10

7. Early life history ofGnathophis catalinensis and larva ofBathycongrus varidens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

8. Distribution ofGnathophis catalinensis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

9. Early life history stages ofHildebrandia nitens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

10. Distribution of Hildebrandia nitens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . 15

II. Early life history stages ofBathycongrus macrurus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

12. Distribution ofBathycongrus macrurus and B. varidens 17

Tables

1. Changes in proportional measurements of congrid leptocephali that take place during metamorphosis 2

2. Seasonal distribution and relative abundance of congrid leptocephali in the eastern Pacific . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

iii

Congrid Eels of the Eastern Pacific and

Key to Their Leptocephali

SOLOMON N. RAJUI

ABSTRACT

This study indicates that 13 species of congrid larvae belonging to 8 genera occur in the eastern Pacific. The

species are: Ariosoma gilberti; Paraconger californiensis; Paraconger sp.; P. dentatus; Chiloconger labiatus;

Taenioconger digueti; T. canabus; Gorgasia punctata;.G. obtusa; Gnathophis catalinensis; Hildebrandia nitens;

Bathycongrus macrurus; and B. varidens. The morphological and anatomical changes undergone during

metamorphosis are useful in the identification of the larvae. Larvae are distributed closer to the coastal waters,

and are more common from January to May than from June to December. A key to the larvae was developed

based on the myotomal counts, adult vertebral counts, pigmentation patterns, and the nature ofthe teeth and tail

tip to distinguish the genera and species. This study shows that Garman's unidentified larvae, Atopichthys acus

and A. cingulus, are two different larval stages ofAriosoma gilberti, and points out that Atopichthys dentatus and

A. obtusus belong to Paraconger and Gorgasia, respectively.

INTRODUCTION

Eels of the family Congridae (except Conger) are usually small

with moderately large pectoral fins and eyes and a slightly protruding upper jaw. They have a worldwide distribution in tropical

and temperate waters and are essentially benthic or fossorial in

habit. They form one of the most abundant and speciose families

of eels. In the past, about 50 genera (including larval forms) were

assigned to this family, but a recent study (Smith 1971) indicates

that there may only be about 20 valid genera.

One problem in studying congrid eels is the limited availability

of adults due to benthic and fossorial habit of most species;

however, the larvae are easily collected in plankton nets, and in

some cases help to predict the occurrence of unrecorded and

unknown adults in that area. Such a prediction of the possible

occurrence of two more species ofParaconger is made on the basis

of this study.

The following congrid eels are known to occur in the eastern

Pacific: Ariosoma gilberti, Paraconger californiensis, Paraconger

sp., P. dentatus, Chiloconger labiatus, C. similis, Congrosoma evermanni, Taenioconger digueti, T. canabus, Gorgasia punctata, G. obtusa, Gnathophis catalinensis, Hildebrandia nitens, Bathycongrus

macrurus, B. varidens, and Ophisoma prorigerum. This list also includes those which are predicted to be present on the basis of the

presence of the larvae (e.g., Paraconger sp.).

The earliest account of the congrids of the eastern Pacific

appears to be that of Jordan and Gilbert (1883), who gave a brief

description of Leptocephalus conger (Ariosoma gilberti) from Cabo

San Lucas. Important accounts of eastern Pacific congrids include

those of Gilbert (1891), Ogilby (1898), Garman (1899), Meek

and Hildebrand (1923), Pellegrin (1923), Myers and Wade

(1941), Wade (1946), Rosenblatt (1958, 1967), Kanazawa

(1961), Cowan and Rosenblatt (1974), and Raju (1974).

Garman's (1899) account of the nine different congrid leptocephali and Wade's (1946) description of Thyreoconger hemiI Scripps Institution of Oceanography, Marine Life Research Group, La Jolla,

Calif.; present address: City College of San Francisco, 50 Phelan Ave., San Francisco, CA 94112.

aspidus are the only accounts of congrid larvae of the eastern

Pacific. This study is aimed at the identification, metamorphosis,

and distribution of the larvae.

NOTES ON TAXONOMY AND

DISTRIBUTION

Taxonomy

Congrid eggs are large like other eel eggs and were described by

Grassi (1913), Thomopoulos (1956), Castle (1969a), and Castle

and Robertson (1974). The egg described by Eigenmann (1902) as

a conger eel egg was an ophichthid egg (Naplin and Obenchain

1980).

Early leptocephalus stages are usually 10-20 mm long, and are

poorly preserved. In some cases the pigmentation is different from

the full-grown leptocephalus stages (D'Ancona 193 I; Castle

1964). Most congrid leptocephali attain an average length of 150

mm. Ariosoma scheelei (Castle 1964) and Bathycongrus varidens

attain a length of 300 mm and 250 mm, respectively.

A trailing gut is present in the larvae of Bathymyrus and some.

species of Ariosoma (Smith 1979). My observations showed that

the digestive glands are rudimentary in the leptocephalus stages

and are devoid of any recognizable food. The gut shrinks in length

during metamorphosis, the position of the anus shifts, and both

the stomach and liver increase in size. The vent is shifted more

anteriorly in large larvae than in small larvae. The changes in proportional measurements are given in Table 1.

I found in my study that the dorsal finfold is high in all genera

except in the Heterocongrinae, and the segmented or unsegmented

nature of rays can be seen only in late metamorphic and juvenile

stages. The caudal fin is pointed in the larvae of Hildebrandia

nitens, Bathycongrus macrurus, and B. varidens, and round in all

the members of the Congriscus (Asano 1962), Conger (Smith

1979), and Gnalhophis.

The diagnostic value of the eye in the Congridae (round in the

Bathymyrinae and oval with a pigment patch below iris in the

Congrinae) was pointed out by Castle (1964). Pigmentation,

especially lateral pigmentation, is useful in identification of the

congrid larvae. Congriscus (Asano 1962), Conger (except some
Table I.-Changes in proportional measurements of congrld leptocephali that take place during metamorphosis.

Total Snout Eye

length Depth Head increase/ increase/ Predorsal Preanal

reduction reduction increase decrease decrease amplitude amplitude Number of

(%) (%) (%) (%) (%) (%) (%) specimens

Ariosoma gilbeni 57.2 6.0 16.0 0.7 1.3 80.5 55.5 13

Paraconger californiensis 44.8 6.7 10.8 1.0 1.8 67.3 55.7 14

Taenioeonger spp. 22.6 8.6 3.6 -1.0 0.3 15.7 46.0 9

Gorgasia punelala 20.0 8.2 3.0 -1.9 0.5 16.8 47.3 4

Gna/lwphis ea/alinensis 27.0 5.3 13.3 4.0 3.0 47.6 45.0 13

Hildebrandia ni/ens 34.3 8.4 9.7 2.2 0.5 29.0 64.0 14

Bathycongrus macrurus 42.6 5.0 5.5 1.0 1.7 55.6 64.0 14

Ba/hyeongrus varidens 54.4 6.3 16.5 2.5 1.7 67.5 59.3 15

species, Smith 1979), and Gnathophis larvae lack lateral pigmentation. Parabathymyrus (Smith 1979) and Ariosoma larvae have

lateral pigmentation in oblique rows on myosepta. A single row of

midlateral pigment is present in Paraconger, Chiloconger, Taenioconger, Nystactichthys, Gorgasia, Hildebrandia, and Bathycongrus

macrurus studied by me, and in some species of Rhechias and

Uroconger studied by Smith (1979). Three rows of lateral pigment

spots are present in Rhechias guttulata (Smith 1979) and Bathycongrus varidens (present account). Leptocephalus splendens (Lea

1913), which was identified as the larva of Pseudophichthys

(Smith 1979), has three irregular midlateral rows of pigment and

large patches of pigment below the midlateral line. Lateral

pigmentation persists into the jrJvenile stages in Paraconger,

Taenioconger, Nystactichthys, and Bathycongrus studied by me, and

in Rhechias and Pseudophichthys studied by Smith (1979).

Seasonal Distribution and Relative Abundance

Table 2 shows the relative abundance of the different species in

different months of the year, but this may not give the correct picture of the actual distribution in the ocean, as samples were not

collected systematically. Neverlheless, it does portray a rough picture of the relative abundance of different species. The number of

leptocephali of many species is usually very high in May. Leptocephali are more common from January to May than from June to

December.

MATERIALS AND METHODS

Specimens

The study is based on about 4,000 leptocephali, metamorphic

larvae, juveniles, and adults of the congrids of the eastern Pacific.

Most of the material studied came from the Scripps Institution of

Oceanography, collected over a period of 20 yr from the following

cruises: CalCOFI (1950, 1961, 1964), Northern Holiday Expedition (1951), Shellback (1952), Pelagic Area Survey (1954),

EASTROPAC (1955, 1967), Tuna Spawning Survey (1957), Tuna

Oceanography-58-2, Tuna Oceanography-59-1, and Vermilion

Sea Expedition (1959). Material from the Los Angeles County

Museum of Natural History, University of California at Los

Angeles, University of Southern California, and the National

Marine Fisheries Service at La Jolla, was also used to find metamorphic forms and station data for distribution. Material at the

National Museum of Natural History, Washington, DC; Smithsonian Oceanographic Sorting Center, Washington, DC;

American Museum of Natural History, New York; Woods Hole

Oceanographic Institution; and the British Museum of Natural

History, London, was examined for the purpose of identification

and comparison.

Most of the specimens and the station data are available for

reference in the fish collections of the Scripps Institution of

Oceanography, La Jolla, and Los Angeles County Museum of

Natural History. Two published catalogues on zooplankton

samples (Snyder and Fleminger 1965, 1972) will also provide

most of the station data. Almost all material comes from the area

ranging from southern California to Colombia. The terms used for

the description of the larvae are after Castle (1963).

Identification

Larvae were identified by tracing characteristics of juveniles

and metamorphic forms backwards to the larval forms. Adults

were studied in most cases, and their vertebral counts and other

morphological characteristics were taken into consideration to

establish the identities. Metamorphic forms, juveniles, and adults

were also dissected to study the anatomy.

Table 2.-Seasonal distribution and relative abundance of congrid leptocephali In the eastern Pacific.

Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Total

Ariosoma gilberti 141 72 8 90 264 75 8 0 0 3 40 19 720

Paraconger californiensis 137 20 3 25 328 169 1 0 I 0 28 0 712

Paraconger dentatus 9 3 0 2 28 0 0 0 0 0 46 0 88

Paraeonger sp. 0 0 0 1 5 0 I 1 1 0 0 I 10

Taenioeonger spp. 13 3 0 750 5 82 3 4 0 0 0 0 860

Gorgasia punelala 0 0 0 3 0 0 0 0 0 0 0 0 3

Gna/hophis ea/alinensis 2 II 0 11 0 10 6 I 2 7 4 0 54

Hildebrandia ni/ens 120 32 35 54 527 326 44 5 10 2 62 0 1,217

Balhyeongrus varidens 0 15 0 0 15 26 3 3 0 0 0 0 62

Bathycongrus macrurus 2 I 0 2 I 1 0 0 0 0 0 0 7

Grand total 3,733

2
Measurements (Table 1)

Measurements of total length, body depth, head, and predorsal

and preanal distances were taken with dial calipers, and those of

snout, eye, and other small structures with all ocular micrometer.

The values are rounded to the nearest millimeter. The descriptions

given in the text under each species apply to the leptocephalus

stages but not to the metamorphic and juvenile stages. The percentage of depth and head were calculated from the total lengths, and

those of the snout and eye from the head length. The percentage of

total length reduction after metamorphosis was calculated by subtracting the total length of the metamorphosed (smallest

specimen) form from the length of a full-grown (largest premetamorphic) form, the percentage being computed in terms of the

total length of the full-grown form. The percentage of depth

reduction and snout increases or decreases were calculated as

above. In Gnathophis catalinensis, a juvenile form is used in place

of a metamorphic form for measurements since no metamorphic

form of G. catalinensis was available.

The amplitude of the dorsal fin is the distance moved by the

dorsal fin from its original point before metamorphosis to its point

at metamorphosis. The percentage amplitude of the dorsal fin is

calculated as follows: The percentage of the predorsal distance

of the metamorphic form is subtracted from the percentage of

predorsal distance of the full-grown larva. The percentage amplitude of the anal fin is also calculated as above.

Methods of Collection

Leptocephali were collected by Isaacs-Kidd Midwr.ter Trawl,

midwater trawl, universal trawl, otter trawl, bottom trawl, nekton

net (5' x 5'), Hansen Net, meter net (I m), and dip net: metamorphic forms were collected by using rotenone and dredges.

Drawings

Drawings were made by using a camera lucida and an overhead

projector.

Abbreviations

SIO = Scripps Institution of Oceanography, LACM = Los

Angeles County Museum of Natural History, UCLA = University

of California at Los Angeles, NMFS co National Marine Fisheries

Service, La Jolla, CA, TL = Total length, ETP = EASTROPAC,

TS = Tuna survey.

KEY TO THE CONGRID LEPTOCEPHALI

OF THE EASTERN PACIFIC

1a. Tail tip blunt and round. . . . . . . . . . . . . . . . . . . . . . . . .. 2

I b. Tail tip pointed 10

2a. No lateral pigment, black patch below iris, myotomes

128-132 . . . . . . . . . . . . .. . Gnathophis catalinensis

2b. Lateral pigment as single row on lateral line or as an

oblique row on myosepta, no black patch below iris. . .. 3

3a. Teeth conical, few, not compressed. . . . . . . . . . . . . . . .. <1

3b. Teeth laterally compressed, bladelike. numerous. . . . .. 8

4a. Lateral pigmentation on myosepta as a series of oblique

lines, snout moderate size, myotomes 126-138 .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ariosoma gilberti

4b. Lateral pigmentation as a single row of mid lateral

melanophores, snout short, myotomes 138-199. ..... 5

3

Sa. Myotomes more than 170, caudal fin narrow. . . . . . . .. 6

5b. Myotomes less than 170, caudal fin broad 7

6a. Myotomes 170-191 (with mode around 185), body

pigmentation as patches in late metamorphic larvae ...

............................. (?) Taenioconger digueti

6b. Myotomes 186-208 (with mode around 192), body pigment uniform as minute spots in late metamorphic

larvae (?) Taenioconger canabus

7a. Myotomes 119-121 Gorgasia obtusa

7b. Myotomes 138-156 Gorgasia punctata

8a. Maximum TL 250 mm, myotomes 150-162, one midlateral dot for every 5-10 myotomes Paraconger sp.

8b. Maximum TL not greater than 165-170 mm, myotomes

J 18-146, midlateral dot on every myotome or absent on

some myotomes . .. 9

9a. Body size moderate, attains 165-170 mm, myotomes

138-146, midlateral dots lacking on some myotomes ...

............................Paraconger californiensis

9b. Body small, attains 120-125 mm, myotomes 118-124,

midlateral dots on every myotome ... .Paraconger dentatus

lOa. Lateral pigment superficial as three rows of dots, maximum TL 250 mm Bathycongrus varidens

lOb. Lateral pigment superficial or internal in the form of a

single midlateral row of dots, maximum TL 160-170

mm 11

lla. Midlateral row of dots superficial, no pigment dots on

upper jaw Bathycongrus macrurus

11 b. Midlateral row of dots internal, 1-3 pigment dots on

upper jaw Hildebrandia nitens

SUBFAMILY BATHYMYRINAE

Ariosoma gilberti (Ogilby 1898)

Figures 1,2

Literature.-The synonymy of this species was given by

Rosenblatt (1958). Larvae of this species were described by Garman (1899) as Atopichthys acus and A. cingulus. These two specimens are different stages of Ariosoma gilberti. Larvae of Ariosoma

spp. have been described by various authors (Castle 1964; Blache

1977; Smith 1979).

Identification.-The oblique series of closely packed, microscopic, linear melanophores are characteristic of all Ariosoma spp.

The melanophores on the myosepta disappear with the onset of

metamorphosis and can lead to incorrect identification. The vertebral counts of Ariosoma gilberti (47-50) + (77-89) = 124-139

agree with the larval myotomal counts (126-138). The dorsal and

anal fin ray counts of metamorphic forms agree with those of

adults.

Material Examined.-61I specimens, 83-206 mm TL. Baja

California and Gulf of California: S10 59-201(1), 60-276(1),

61-21(1), 64·12(1), 64-13(1), 64-15(1), 64-16(2), 64-23(1),

64-26(4), 64-27(8), 65-236(2), 65-253(4), 68-50(10),

68-132(5), 63-818(1), 63-865(21), 75-551(1), 63-933(12),

75-546(1), 75-564(7), 75-565(2), 75-566(10), 63-973(2),

63-975(5), 63-978(2), 63-616(62), 63-866(3), 60-7(1),

61-249(1), 64-27(2), 65-253(5), 65-564(1), 68-50(10),

68-132(4), 60-111(1), 62-77(2), 62-702(1), 62-709(2),

60-89( I), 59-261 (1). Mexico: SIO 54-91 (1), 54-92(1),

63-509(1), 73-249(13), 63-819(2), 63-822(1), 63-823(2),

63-824(3), 63-861 (20), 63-864(20), 63-857(9), 63-922(2),
A f----------<

:3 mm

B

t

t-----l

5 mm

~~ .~=='T7~=======

C : ::::::::=:

5 mm ..

..,.

t-------l

5 mm

F G

t

pI------'<

Imm

H

5 mm t-------f

2 mm

eo dJ;

2

t-------f

mm ~~

K~ ~/~ L f--i

2 mm >-------'

2 mm

M

.~ .

0------<

2 mm

Figure I.-Early life history stages ofAriosoma gi/berti. A. Fullgrown larva; B. early metamorphic form; C. late metamorphic form; D. early juvenile; E. late juvenile; F. head of full grown larva; G. caudal end of fullgrown larva;

H. head of early metamorphic form; K. head of early juvenile; L. head of late juvenile; M. body segment of late juvenile.
30·

O·

90· 60'

•

Ariosoma gilberti

• larvae

... metamorphic forms

• juveniles

• adults

.,..

•

•

•

100·

•

• •

•

•

•

• •••• ".. . •

120·

•

'----_---'-__---'--_.._-.-L__l--__---'- ---'-__.L-_---'-__=-_----' 110·

30·

O·

20·

L

"lI

Figure 2.-Distribution of Ariosoma gilberti based primarily on SIO collections.

63-924(2), 63-923(15), 63-932(69), 63-930(2), 63-931(13),

75-544(1), 75-542(6), 7 5-545(1), 63-973(2), 63-913(2),

63-510(2), 63-509(1), 63-521 (2.). Central America: SIO

55-213(1), 53-138(1), 58-4 22(1), 63-826(7), 63-829(2),

63-835(24), 63-75(4), 62-640(12), 63-839(36), 63-858(8),

63-854(11), 63-851 (14), 63-853(52), 63-852(21), 63-856(15),

63-855(8), 63-927(3), 63-929(8), 63-524(5), 64-198(4),

66-458(1), 73-263(23), 75-554(12), 75-556(4), 75-559(2),

75-560(3). Colombia: SIO 62-387(1), 55-246(3). 55-247(3),

55-258(3), 63-838(5), 63-841 (1), 63-842(1), 63-843(4),

63-848(9), 63-849(1), 63-845(3), 63-846(1), 69-8(2),

63-299(1), 63-1022(1).

Description (based on 13 specimens, 83·206 mm TL).-Body

elongate; an oblique series of closely packed, superficial, linear,

microscopic melanophores on midlateral myosepta ranging from

1 to 30, beginning at myotome 5; a series of round superficial

melanophores Oll the dorsal side beginning at myotome 7 to origin

of dorsal; a paired series of superficial melanophores on the ventral side beginning from level of pectoral fin (0 level of stomach; a

series of linear, internal melanophores on dorsal side or intestine

from level of stomach to vent. One dotlike internal melanophore

at the base of each anal and dorsal ray. Preanal distance 94-96%;

predorsal distance 96%; head 2-3%; greatest depth 9-11 %; total

myotomes 126-138; preanal myotomes 121-128; last blood ves;>el

at myotome 26-27; caudal rays 6; tooth formula 1+(4--5)+(6-·8).

1+(4-·6)+ (6-9)

Metamorphic Forms and Juveniles (Table 1).-Metamorphosis sets in when the larvae are about 200 mm long and ihe

pigmentation on the myosepta disappears abruptly. The juvenile

pigmentation appears as very smal1 brown chromatophorcs on the

dorsal and lateral sides, and becomes denser in the laler ~tages. No

black pigment is present on the viscera.

The total length reduction (57.2%) and increase in head length

(16.0%) and predorsal amplitude (80.5%), are the highest among

the 13 species studied. The increase in snout length (0.7%) and

decrease in body depth (6.0%) are moderate.

Abundance.-The leptocephali of A. gilberti are among the

most abundant in the larval eel collections of the eastern Pacific.

Distribution (Fig. 2).-The larvae occur over a large area of

the tropical and temperate regions of the eastern Pacific (lat.

28°41'N to the Equator, and from the Gulf of Panama to long.

120°57 'W). The distribution map shows the occurrence of the larvae in the offshore waters and the metamorphic forms in the near

shore. Presumably the larvae, after being swept away by the currents, will begin to move toward coastal regions after metamorphosis and settle down to begin their fossorial life.

Larvae were obtained throughout the year except in August and

September; the maximum numbers were obtained in May and

January (Table 2). Metamorphic forms were obtained in January,

February, May, June, and November; the maximum number collected was in May.

Discussion.-Atopichthys acus (127 + 8 = 135 myotomes) and

Atopichthys cingulus of Garman (1899) are assigned to Ariosoma

gilberti on the basis of myotomal counts and pigmentation. Castle

(1964) suggested that Atopichthys dentatus and A. obtusus of Garman belong to Ariosoma gilberti. I have assigned Atopichthys dentatus to Paraconger and Atopichthys obtusus to Gorgasia on the

basis of myotomal counts and pigmentation. The adults of the

Indo-West Pacific species, Ariosoma scheelei and A. mauritianum,

were also suggested to be synonymous with A. gilberti by Castle.

The myotomal count of A. scheelei (115) is lower and that of A.

mauritianum (134-153) is higher than the myotomal count of A.

gilberti (126-138).

5
Paraconger californiensis Kanazawa 1961

Figures 3, 4

Literature.-One of the distinguishing features of Paraconger

is the compressed teeth that form a cutting edge, a characteristic

shared by their larvae. Of the six species reported by Kanazawa

(1961), only P. californiensis is known to occur in the eastern

Pacific. Castle (1966, 1970), Blache (1977), and Smith (1979)

identified and described larvae of Paraconger from the Atlantic.

Larvae of P. californiensis are identified here for the first time, and

the larvae of another new species of Paraconger are described.

Identification.-Identification of the larvae was made with the

help of metamorphic forms which retained the larval midlateral

pigmentation. The myotomal counts of the larvae agreed with

those of the metamorphic forms and with the vertebral counts

(137-148) of juveniles and adults. The larval teeth are characteristically compressed. The absence of the crescentic patch of pig2mm

o

..

E G WIJIJ

H

@--z tC)

k

<~

I J

20 111M

Figure 3.-Early life history stages of Parac9nger californiensis and larva of Paraconger sp. A. Fullgrown larva; B. early juvenile; C. late juvenile; D-F. head, midbody,

caudal end of fullgrown larva; G. teeth; H·J. head, midbody, caudal end of early juvenile; K. fullgrown larva of Paraconger sp.

6
ment under the eye, blum tail fin, and unsegmented fin rays help

to assign these larvae to the Bathymyrinae, and the compressed

teeth refer them to Paraconger.

Material Examined.-191 specimens, 60-165 mm TL. Gulf of

California and Mexico: SID 63-616(6), 63-933(2), 63-921(1),

63-818(1), 63-864(1 metamorphic), 63-922(1), 63-932(4),

73-235(1), UCLA W-52-12(2 metamorphic), W-57-116(1 metamorphic), SID 73-249(13), 63-931(3), 63-76(3), 63-930(6),

63-961(2), 73·263(12), 63-834(21), 63-858(53), 63-925(5),

75-556(13), 63-852(2), 63-927(1), 63-836(1), 63-839(1).

Colombia: SID 55-249(7), 55-242(26), 61-421 (1), 62· 387(1).

(55.7%) amplitudes is also high.

Distribution (Fig. 4).-The larvae of P. californiensis are

distributed along the coast from Cabo San Lucas to Panama; the

adults extend to Peru (Kanazawa 1961). Larvae were collected in

all months of the year except August, October, and December; the

maximum number collected was 328 in May. Metamorphic forms

were collected in January and April, and juveniles were collected

in March. Larvae were abundant.

Paraconger sp.

Figures 3K, 4

Description (based on 14 specimens, 60-165 mm TL).-Body

elongate; a series of dotlike melanophores on most myotomes on

midlateral line beginning at myotome 10; a series of paired

lIlelanophores on ventral side beginning at stomach bulge to end

of body; a series of small melanophores at base of anal, caudal,

and dorsal fin rays; a series of 3-4 melanophores in heart region.

Preanal distance 89-90%; predorsal distance 80-84%; head 5-8%;

greatest depth 7-12%; total myotomes 135-143; preanal myotome~, 104-120; last .blood vessel at myotome 54-57; caudal rays 4

+ 3 = 7' teeth compressed; tooth formula I +(9-10)+(26-3

2

61. . 1+(10-13)+(18- )

Literature.-This larva has not previously been reported or

described.

Identification.-The larvae were identified as belonging to

Paraconger on the basis of the compressed teeth and midlateral

pigmentation. They differ from the larvae of P. californiensis in

higher myotomal count (150-167), larger size (127 -250 mm TL),

and sparse midlateral pigmentation. Since no adults of Paraconger

with a vertebral count of 150-167 are known, these larvae are

provisionally assigned to Paraconger sp., which is possibly a new

species of the eastern Pacific.

Metamorphic and Juvenile Forms (Table 1).-Larval pigmentation on the midlateral li::Je and ventral side are retained in

early juvenile stages but disappear in late juvenile stages. Juvenile

pigmentation appears as minute brown dots all over the body, and

the margin of the median fins becom~s black. Only the rectum

develops brown pigment.

The reduction (44.8%) in total length is high. The increase

(10.8%) ia the head length, predorsal (67.3%), and preanal

Material Examined.-14 specimens, 93-245 mm TL. Mexico

to Colombia: SIO 75-563(1), 63-850(1), 63-838(1), 63-841(1),

62-639(1), 60-580(1), 62-387(1), 63-1081(1), 55-265(1),

75-534(1), NMFS ETP 1l.l 14(2), 11.246(1), 11.098(1).

Description (based on 11 specimens, 93-245 mm TL).-Body

elongate; a series of dotlike melanophores on many myotomes on

midlateral line beginning at myotome 10-12; a series of paired

20·

O·

30·

': 10·

90· 80·

80·

Paraconger californiensis

'" • larvae

(

',': ~eta~orphic forms ,\ • Juveniles ....)

C Paraconger sp. 4\ '~:.-larvae

\\ Paraconger dentatus

"'~i'J,?~vae ',;

30·

I

I •

20·r

I

r- IO·

O· -

Figure 4.-Distrlbution of Paraconger californiensis, Paraconger sp., and Paraconger denlalus based primarily on SIO

collections.

7
melanophores beginning at stomach bulge to end of body; a series

of small melanophores at base of anal, caudal, and dorsal fin rays;

a series of 3-4 melanophores in heart region. Preanal distance

91-95%; predorsal distance 84-88%; head 5-6%; greatest depth

9-11%; total myotomes 150-167; preanal myotomes 130-142;

last blood vessel at myotome 65-68; teeth compressed; tooth

formula 1+(8-9)+(28-50)

1+(12-17)+(20-40)

Metamorphic Forms.-The midlateral pigmentation becomes

inconspicuous in metamorphic forms (due to contractions of the

melanophores) and probably disappears in the juveniles. No

juveniles were obtained. The metamorphic forms obtained were in

very early stages and no significant changes in body proportions

were noticed.

Distribution (Fig. 4).-The larvae are mostly confined to the

offshore waters of Costa Rica and Panama. Of the three species of

Paraconger, this species has the most southerly distribution,

extending beyond the Equator. Larvae were collected in April,

May, July, August, September, and December; the maximum

number collected was 5 in May. Metamorphic forms were obtained in November. Larvae are rare in the collections.

Paraconger dentatus (Garman) 1899

Figure 4

Literature.-Castle (1964) suggested that Atopichthys dentatus

is possibly the larva ofAriosoma gilberti. Larval features, however,

suggest that this is not the larva of Ariosoma.

Identification.-The compressed teeth and midlateral pigmentation show that this larva belongs to Paraconger. It differs from

the larvae of P. californiensis and Paraconger sp. in having a lower

myotomal count (109-125), irregular midlateral pigmentation,

and relatively smaller ~e (40-125 mm TL). The characteristics

of the larvae agree with those of A. dentatus of Garman.

Material Examined.-84 specimens, 40-125 mm TL. Mexico

to Colombia: SIO 68-50(8), 63-616(2), 63-922(1), 63 -929(1),

73-263(2), 63-851 (5), 55-235(1), 62-640(2), 75-558( I),

63-848(3), 63-838(3), 63-849(2), 63-841(1), 63-843(4),

63-845(5),55-242(39), 55-249(4).

Description (based on 11 specimens, 40-125 mm TL).-Body

elongate; a series of midlateral melanophores on myotomes which

are more regular than in P. californiensis. Pigment spots at base of

anal and dorsal rays absent in some specimens_ Preanal distance

83-95%; predorsal distance 57 -95%; head 6-10%; greatest depth

9-12%; total myotomes 109-125; preanal myotomes 98-109; last

blood vessel at myotome 44-50; teeth compressed; tooth formula

1+(8-11)+(15-30)

1+(10-16)+(9-16)

Metamorphic and Juvenile Forms.-No metamorphic or

juvenile forms were obtained.

Distribution (Fig. 4).-The larv~e show an intermediate position in distribution between P. californiensis and Paraconger sp.,

and are mostly distributed off the Pacific coast of Guatemala, EI

Salvador, and Nicaragua, although some have been found near

Cabo San Lucas. Larvae were obtained in January, February,

8

April, May, and Novembe.r; the maximum number collected w~s

46 in November. The larvae were not abundant.

Chiloconger labiatus Myers and Wade 1941

(Not illustrated)

Myers and Wade (1941) described this species from a very

early juvenile of 83.0 mm which retained the larval pigmentation.

The authors Jid not distinguish the larval pigmentation from that

of the juvenile. A description of the remnant larval pigmentation

and myotomal and vertebral counts are given here to help future

identification of the larvae of Chiloconger.

Larval pigmentatioli: /'. series of dotlike midlateral, superficial

melanophores beginning at myotome 15 and extending to the

caudal end. A series of microscopic melanophores at the base of

median fin rays. Two melanophores on ventral side.

Juvenile pigmentation: Dorsal and lateral sides uniformly

covered with brown dots as described by Myers and Wade.

Vertebral counts: Chlloconger labia/us, 39 + 83 = 122. Myotomes 42 + 84 = 126.

Chiloconger similis Wade 1946

Wade (1946) described Chi/oconger similis from the eastern

Pacific. The vertebral r.ount of this species is gi ven here to facilitate identification of the larvae. Vertebral (;Qunts 50 + 96 = 146.

SUBFAMILY HETEROCONGRINAE

Taenioconger digueti Pellegrin 1923 and

Taenioconger canabus Cowan and Rosenblatt 1974

Figures 5 A-D, 6

Literature.-The literature, description, and distribution of the

larvae of Taenioconger were given in an earlier acr.ount (Raju

1974). Subsequently, Cowan and Rosenblatt ~1974) described a

new species, T. canabus, from the eastern Pacific. The above

authors synonymized T. herrei Wade with T. digueti in their account. A part of the information of the previous account (Raju

1974) is included in this paper for the purpose of comparison and

to supplement the material on congrid larvae. As the previous

description was based on a single specimen, a redescription of the

Taenioconger larvae based on several specimens is given.

Identification.-The larvae closely resemble those of Paraconger and Hildebrandia in general appearance and the midlateral

pigmentation. They can be distinguished from the Paraconger larvae by higher myotomal count, smaller conical teeth, shorter

snout, longer dorsal fin, and shorter gut. The larvae of Hildebrandia differ from those of the Taenioconger in having a whiplike tail,

deep midlateral melallophores, and fewer myotomes.

Taenioconger larvae of the eastern Pacific have 170-208

myotomes. Cowan and Rosenblatt (1974) separated T. digue/i

(vertebral count 179-191) from T. r:anabus (vertebral count

186-199) on the basis of vertebral counts, pigmentation. ar.d other

features. The larvae could not be assigned to either of the two

species due to overlapping of the myotomal counts. The myotomal

counts have a mode around 185 or 192 in most larvae.
~..,.--,-~~~~-.---;;--;-~~:-;-;-;-~~~ ..-.;- - _ - .

c,

D

E

FI

.. .. .. .

t

.. .... .. .. .. .. ... ... .. ... .. .. .. .. . . ...

t

t

.. .......

IOmm

'~.""'... ., ....

IOmm

IOmm

A2

2mm

~~_:_;:-

~~

82

5 mm 2 mm

IOmm

2 mm

o I

Figure S.-Early life history stages of Taenioconger spp., juveniles of T. digueti and T. canabus, and larvae ofGorgasia punctata and G. obtusa. A" A,. Larva and head of

Taenioconger sp.; Bp B,. larva and head of early metamorphic form of Taenioconger sp.; C" C,. larva and head of early juvenile of T. digueti; D. early juvenile of T.

canabus; E. fullgrown larva of Gorgasia punctata; FI' F,. larva and head of Gorgasia obtusa.

Postmetamorphic torms can be distinctly separated by their

early juvenile pigmentation. The body pigmentation of the early

juveniles of T. digueti ha3 a patchy pattern, whereas it is uniform

in T. canabus.

Material Examined.-Taenioconger sp. (larvae), 970 specimens, 68-115 mm TL. Gulf of California to Galapagos Islands:

S10 62-14(4), 62-639(1), 63-616(70), 63-856(2), 63-859(3),

63-861 (3). 63-864(5), 63-920(1), 63-921 (2), 63-922(8),

63·932(3), 63-960(1), 65-253(1), 68-54(2), 74-249(750), TS

63( I), TS 5407P-15(1). Taenioconger digueti (juveniles and

adults), 100 specimens, 110-180 mm TL. SIO 62-42(100).

9

Taenioconger canabus (juveniles and adults), 121 specimens,

90-284 mm TL. SIO 61-261 (50), 62-42( II), 72-41 (60).

Description of the Larvae of Taenioconger sp. (based on 8

specimens, 87·115 mm TL).-Body elongate; a series of midlateral melanophores beginning at myotome 15-20 to end of

caudal region; a series of melanophores on ventral side beginning

at myotome 10-13 and continuing to end of body; a series of 4-5

melanophores in heart region; a series of very fine melanophores

at base of anal and dorsal rays; 1-2 melanophores at angle of jaws

in some. Preanal distance 66-76%; predorsal distance 21-30%;

head 5-7%; greatest depth 9-12%; total myotomes 170-208;
30°

80°

80°

90°

90°

..". .~. ".

•

" Taenioconger spp.

:~:f<;'; · larvae

":~:~ Taen;ocon~er canabus

'.:: • juveniles

.~ Taenioconger digueti

'~ • juveniles

•

100°

•

•

Gorgasia obtusa

.... metamorphic form

Gorgasia punctata

• larvae

30°

Figure 6.-Distriblltion of larvae and juveniles of Taenioeonger spp., T. digu,/i, T. eanabus, Gorgasia pune/ala, and G.

ob/usa based primarily on SIO coilections.

preanal myotomes 115-130; last blood vessel at myotome 64-78;

caudal rays 4 + 3 = 7' tooth formula 1+(7-10)+QO-24). , 1+(8 -9)+(6-12)

Metamorphic and Juvenile Forms (Table l).-One of the

late metamorphic forms of T. canabus (108 !Tim TL) was very

transparent and cylindrical, and the pecioral fins were clear without any pigmentation. The body pigmentation was uniform with

stellate melanophores on the head and lateral side of the body. Advanced stages of this species have black pectorals and a thick

uniform pigment on the body. The pigment in T. digueti (! 10 mm

TL) has a patchy pattern.

The reduction (22.6%) in total length is small, but the reduction

(8.6%) in body depth is higher. The increase in head length (3.6%)

and the eye (0.3%) are among the lowest. The snout length

(-1.0%) is even smaller than that of the full-grown larva.

Identification.-Larvae were identified by tracing the characteristics of the juveniles of G. punctata back to the larval stages.

The early juveniles retained the larval midlateral pigmentation,

indicating the presence of midlat.eral pigmentation in the leptocephali. The larvae resemble those of Taenioconger in this respect,

but the higher myotomal counts (170-208) of the larvae of the

Taenioconger spp. help to distinguish the larvae of Gorgasia punctata with lower myotomal count (137 -159). The myotomal counts

(137, 152, 159) of the larvae of Go,-gasia closely agree with the

adult vertebral counts (140-155) of G. punctata. In advanced

metamorphic stages of larvae of G. punctata, the tubular nostril is

distinct and separate fram the upper lip as in the adults. The larvae

also bear a close resemblance to those of muraenids in their body

shape and the caudal fin, but the absence of the midlateral series

of melanophores in muraen;ds rules out the possibility of mistaking them for muraenid larvae.

Distribution (Fig. 6).-The larvae are distributed between lat.

00012'53"S and 23°53'N, and long. 111 039'W and 86°43'W.

Larvae were collected from January to February, and from May to

July; the maximum number collected was in April. Metamorphic

forms were collected in January, and juveniles in August. The larvae spread out farther from the coastal region than the juveniles

and adults.

Gorgasia punctata Meek and Hildebrand 1923

Figures 5E, 6

Literature.-The literature and the description of Gurgasia

were given in a previous account (Raju 1974). Although the adults

of G. punctata from the eastern Pacific have been known for a

long time, their larvae have not been previously identified.

Material Examined.- 4 specimens, 67-95 mm TL. Pacific

coast of Mexico: SIO 61-248(1), 75-249(3).

Description (based on 3 specimens, 67-95 mm TL).-Body

elongate; a series of midlateral melanophores beginning at myotome II to end of body; a paired series of melanophores on ventral side beginning at myotome 9 to end of body; a series of 2-4

melanophores on upper jaw and another similar series on heart

region; a series of very small melanophores at base of dorsal,

caudal, and anal fin rays..Preanal distance 85-87%; predorsal

distance 28-33%; head 6··7%; greatest depth 11-13%; total

myotomes 137-159; preanal myotomes 118-123; last blood vessel

1+(7-10)+(12-17) at myotomes 57 and 74; tooth formula . 1+(8-11)+(6-10)

10
Metamorphic and Juvenile Forms (Table 1).-No metamorphic forms were obtained. The rnidlateral larval pigmentation

disappears early in juveniles, and advanced stages of juveniles do

not ha ve any trace of midlateral melanophores, unlike those of the

Taellioconger. Juvenile pigmentation appears as patches of brown

spots on the anterior dorsal part of the body, and as uniform

brown dots on the ventral and posterior part of the body. No

development of black pigment is seen in any part of the viscera.

The changes undergone in body proportions are similar to those

of the larvae of Taenioconger.

Distribution (Fig. 6).-The adults and larvae are distributed

from Cabo San Lucas to the Gulf of Panama. The larvae. were collected in April.

Gorgasia obtusa {Garman) 1899

Figures 5Fl, F2, 6

Adults of this species are not yet, known. This larva was

described in an earlier account (Raju 1974) as Gorgasiu sp. (SIO

70-362). G::rmal1 (1899) described a similar larva as AIOpichlhys

obtusus. Since the myotomal counts, pigmentation, and tubular

nostril separate fron', the lip of the larva agre.e with A. obtusus, I

assigned this species :0 C. ubtusa.

Description (based on 1 specimen, 115 mm TL).-Body

elongate; a series of midlateral melanophores; a paired series of

melanophores on the ventral side; a series of small melanophores

at i'he base of dorsal, caudal, and anal fin rays. Predorsal distance

10%; preanal distance 26%; head 8%; greatest depth 15%; total

myotomes 12/; preanal myotomes 55; last blood vessel at

myotome 49.

Metamorphic and Juvenile Forms.-The larva was in the

early stages of metamorphosis.

Distribution (Fig. 6).-The larva was collected off the coast of

Panama.

SUBFAMILY CONGRINAE

Gnathophis catalinensis (Wade) 1946

Figures 7A-H, 8

Literature.-Rhynchucynba (Gnathophi:;) catalinensis was first

described by Wade (1946) from Catalina Island. The adults attain

a maximum size of about 40 cm, and burrow rapidly in the sand

with the tail (Fitch and Lavenberg i 968). The larvae of G.

calalinensis are identified for the first time in this account.

Identitication.-The larvae were identified with the help of a

small juvenile, metamorphic form, and the agreement of

myotomal counts (i 24-132) of the larvae with the vertebral count

(130) of one adult. The larval characters also agree witli those of

Gnalhophis described by Castle (1963, 1968, 1969b) and Castle

and Robertson (1974). The distinguishing features of the larvae of

Gnathophis are the absence of midlateral pigmentation and the

presence of a blunt tail and a crescentic patch of pigment below

the eye. The iris is silvery in fresh or recently preserved specimens, but the silvery pigment fades with time. Th,; larvae could be

confused with those of Ariosoma, especially during metamorphosis, due to the striking similarity in the absence of midlateral

11

pigment and presence of blunt caudal fins. The crescentic pigment

patch below the eye in Gnathophis larvae distinguishes them from

those of Ariosoma.

Material Examined.- 47 specimens, 55-140 mm TL. Baja

California and Gulf of California: LACM 9829-14(1),

30/96-14(1), 30025-4(1). 9667-6(4), 9667(3), 9659-15(1),

9658-5(1), SIO 60-459(1), 75-569(5), 67-61 (5), 68-91 (2),

57-41(2), 63-275(1), 63-280(1), 63-276(1), 63-282(2),

64-36(1), 63-281 (I), 65-425( I), 63-274(1), 63-284(1),

65-213(1), 63-277( 1), 63-274( I), 63-278(2), 63-279(1),

63-285( I), 63-41 (I). Colombia and Galapagos: SIO 55-258(1),

67-154(1).

Description (based on 13 specimens, 55-140 mm TL).-Body

elongate; a crescentic black (silvery in fresh specimens) patch

below and above eye; a group of dotlike melanophores in heart

region; a series of large melanophores on ventral side beginning at

myotome 8 to the vent; a series of densely packed melanophores

at base of anal, caudal, and posterior dorsal fin rays. Preanal

distance 75-91 %; predorsal distance 60-89%; head 5-9%; greatest

depth 11-13%; total myotomes 128-133; preanal myotomes

83-110; caudal fin rays 3 + 3 = 6; last blood vessel at myotome

45-47' 100th formula 1+(4-19)+(10-22) , 1+(4-11)+(9-13)

Metamorphic and Juvenile Forms (Table 1).-Larval pigmentation at the base of anal fin persists into metamorphic and

juvenile stages. The snout in the metamorphic forms becomes

blunt and assumes a hooklike shape. The juveniles have a relatively large head. Patches of densely packed melanophores develop on

the dorsal half of the myotomes and below the midlateralline. The

ventral and ventrolateral surface is free of pigmentation. Black

pigment appears on the stomach and brown pigment on the

anterior part of the intestine in the juveniles.

The reduction (27.0%) in the total length is low. The increases

in the snout length (4.0%) and the eye (3.0%) are the highest. The

increase in head length (13.3%) is moderately high.

Distribution (Fig. 8).-The larvae, metamorphic forms, and

juveniles are distributed from Catalina Island to the Gulf of

California, and disjunctly from the Galapagos Islands to Colombia. Larvae were collected in all months of the year except April,

July, September, October, and November. The larvae probably do

not occur in shoals, as the collections usually contained 1-5 larvae

only, unlike those of Hildebrandia, Taenioconger, and Ariosoma.

Discussion.-Castle (1963) suggested that AIOpichthys cingulus

of Garman could possibly be the larva of G. catalinensis. As

pointed out earlier, it is not the larva of G. catalinensis, but a

metamorphic form of Ariosoma gilberti. Atopichthys cingulus does

110t posses the black patch below the iris. The ventral pigmentation and other features are characteristic of the larvae of

Cnalhophis.

Hildebrandia nitens (Jordan and Bollman) 1890

Figures 9, 10

Literature.-This is a small eel resembling Balhycongrus, but

it differs in having a relatively slender body. The tail is very attenuate with a black border on the median fins. It was first described

by Jordan and Bollman (1890) from the Pacific coast of Panama
F

~=':=®~~~l=-==~

~~=~~~,~~.::::::::::t~~~===?«~~~~~~:::::=::::===~----~~~

B

D

5mm

H

'-." "', '.; .;; -, Q <oJ Q .~ ,'" ~, 'to .." ;J1

J

([JD...

L

Figure 7.-Early Ure history orGnathophis catalinensis and larva orBathycongrus yaridens. Gnathophis catalinensis: A. Fullgrown larva; B. metamorphic rorm; C. late

juvenile; D. head or early larva; E-F. head and caudal end or rullgrown larva; G. head or metamorphic rorm: H. head or late juvenile. Bathycongrus yaridens: I. Fullgrown larva; J-L. head, midbody, caudal end or ruilgrown larva.

12
30" 30°

a~ •

•

•

It • 26° 26°

!

,

•

Gnothophis cata/inensis

• larvae

• metamorphic forms

22° • juveniles 22°

Figure 8.-Distribution of Gnathophis catalinensis based primarily on 510 collections.

as Ophisr>rna miens and later reported as Congermuruella nilens

(Jordan and Evermann, 1896). Jordan and Evermann (1927)

erected the genus Hildebrulldia consisting of COllgermuraella [lava

Goode and Bean 1896 Smith and Kanazawa (1977) synonymized

Congrilla gracilior Ginsburg (1951) and COllg,"vmuraenu guppyi

Norman (1925) with Hildebrundia and redescribed Hildebralldia

(CoIlRromuraclla) guppyi.

Identification .-Larvae were identified on the basis of the

charactel istics of the metamorphic and juvenile forms. The larvae

possess a midlateral series of melanophores which disappear in

both the metamorphic forms and juveniles by gradually sinking

deeper into the musculature from the surface. The deep-seated

pigment spots can be seen in the metamorphic and juvenile forms

by clearing the specimens with glycerine. The vertebral counts of

adults, (30-32) + (138-150) = 168-182, agree with the

myotorr.al counts (170-180) of the larvae.

Material Examined.-I ,234 specimens, 35-140 mm TL. Baja

California and Gulf of California: SIO 68-93(2), 60-97( I),

75-535(2), 65-158(5), 62-207(1). 63-934(1), 75-562(14),

60-90(1),60-89(3),63-920(9),68-50(5), 60-87(1), 63-616(42).

Mexico: SIO 62-51(1), 62-52(4), 63-864(13), 63-932(15),

75-555(12), 'i5-563(8), 73-249(115), 63-860(1), 75-549(110),

63-86i(5), 63-501(1), 65-166(48), 63-504(17), 63-518(15),

63-246(2), 63-522(1), 63-526(8), 63-510(1), 63-923(4),

13

63-924(37), 75-557(1), 75-561(11), 63-857(16). Central

America: SIO 63-1025(14), 63-926(2), 68-380(117),

63-853(22), 73-263(40), 63-1 028( 12), 63-964(2), 63-858(5),

63-856(7), 63-925( 12), 63-929(17), 63-852(21), 63-927(7),

58-355(2), 63-851 (60), 55-235(3), 63-836(17), 62-640(3),

63-839(5), 63-850(12), 64-198(3), 63-1083(1), 63-843(45),

63-838(17), 63-243(1). Colombia: SIO 63-84 I(7), 63-843(27),

62-387(5), 63-846(43), 63-842(5), 63-845(117), 63-847(2),

55-248(48).

Description (based on 14 specimens, 35-140 mm TL).-Body

elongate; a series of midlateral melanophores on lateral surface

beginning at myotome 14 to end of body; a paired series of

melanophores on ventral side beginning at myotome 9 to vent;

dusky black pigment at base of anal, caudal, and dorsal fin rays; a

crescentic, dark patch below the eye; a series of 2-3 melanophores

at angle of jaws, and another series of 3-4 melanophores near

heart region. Preanal distance 79-92%; predorsal distance

32-44%; head 5-6%; greatest depth 9-13%; total myotomes

170-180; preanal myotomes 125-130; last blood vessel at myotome 45-49; caudal fin rays 4 + 4 = 8; tooth formula

I +(4-10)+(6-25)

1+(4-16)+(4-10)

Metamorphic and Juvenile Forms (Table 1).-The crescentic

patch below the eye and the midlateral series of melanophores on
B

IOmm

2mm

o

F G

I

~;.';>"''-:==

smm

J

•• ........... 'O' •• ",J...-!-

Figure 9.-Early life history stages ofHildebrandia nitens. A. FUligrown larva; B. metamorphic form; C. early juvenile; D. late juvenile; E-G. head, midbody, caudal end

of fullgrown larva; H. head of metamorphic form; I-J. head, midbody of late juvenile.

14
20·

Hildebrandia nt'tens 30·

• larvae

• metamorphic forms

• juveniles

• adults

lOa·

•

120·

30·

10· • • 10·

•

Ie •

J a·

120· 110· lOa· 90· BO·

20·

Figure lO.-Distributlon of Hildebrandia nitens based primarily on SIO collections.

the surface disappear during metamorphosis. The juvenile

pigmentation appears as minute brown chromatophores first on

the upper half of the body above the midlateral line, and then

below the midlateral line in later stages. The entire esophagus,

anterior part of the stomach, and the peritoneum become black in

juveniles.

The reduction (34.3%) in total length is moderate, but the

reduction (8.4%) in body depth is one of the highest. The increases in head length (9.7%) and snout length (2.2%) are

moderate. The increase (0.5%) in the eye size is low, as in

heterocongrids.

of adults. The vertebral counts (30-36) + (98-107) = 128-143 of

14 adults (195-265 mm TL) and 7 juveniles (103-140 mm TL)

agree with the myotomal counts 139-151 of the leptocephali and

metamorphic forms. The slightly lower vertebral counts are due to

broken tails.

Material Examined.-90 specimens, 45-145 mm TL. Baja

California and Gulf of California: SIO 68-74(14), 68-92(10),

65-253(3), 63-865(11), 63-920(5), 63-959(3), 68-50(16),

63-933(1), 63-864(5). Mexico to Colombia: NMFS ETP

12.032(1), SIO 63-851 (1), 69-497(1), 63-838(5), 62-639(2),

63-841 (I), 63-842(2), 63-843(6), 63-845(2), 63-846(1).

Distribution (Fig. 10).-The larvae are found from the Gulf of

California to the Gulf of Panama very close to the coastal waters.

They were present in all months of the year except December; the

minimum number collected was 2 in October; the maximum was

527 in May. Metamorphic forms were obtained in October, and

the juveniles in January, March, May, June, and July. These are

the most abundant of all the congrid larvae collected from the

eastern Pacific. They seem to occur in shoals as the samples from

some stations contain large numbers of larvae.

Bathycongrus macrurus (Gilbert) 1891

Figures 11, 12

Description (based on 14 specimens, 45-145 mm TL).-Body

elongate; a series of midlateral melanophores beginning at

myotome 10 to end of body; a crescentic patch below iris and

another above pupil; a series of paired melanophores on ventral

side beginning at myotome 9 to vent; a pair of melanophores on

operculum and another pair in heart region; a series of minute

melanophores at base of dorsal, caudal, and anal fins. Preanal

distance 88-95%; predorsal distance 62-77%; head 4-6%; greatest

depth 11-13%; total myotomes 139-151; preanal myotomes

110 -125; last blood vessel at myotome 49-56; caudal fin rays 5 +

5 = 10' tooth formula 1+(7-11)+(6-30) , 1+(6-10)+(6-20)

Literature.-The species Bathycongrus macrurus is a small but

relatively heavy-bodied eel with a tapering, pointed tail. They

were described by Gilbert (1891) as Ophisoma macrurum from the

Gulf of California, and Ogilby (1898) gave the name Bathycongrus

macrurus.

Identification.-The larvae were identified on the basis of

pigmentation of the metamorphic forms and the vertebral counts

15

Metamorphic and Juvenile Forms (Table 1).-The larval

midlateral pigmentation is retained into late juvenile stages. The

esophagus, stomach, and anterior part of the intestine become

black in the juvenile stages. Some metamorphic forms contained

euphausiids in their stomachs.

The reduction (42.6%) of total length is high, but the body

depth reduction (5.0%) is one of the lowest. The increases in the

head length (5.5%) and eye size (1.0%) are low.
~~ _._, .. o ".~~.. . " ...... '" '" ......' ~:'." ... '

C . . I

10 mm

E

t------l

I mm

F

t------l

2 mm

G

f---l

2 mm

I-------l

0'5mm t------l

2 mm

N AS OP

3 mm

Figure ll.-Early life history stages of Balhycongrus macrurus. A. Larva; B. metamorphic form; C. early juvenile; D. late juvenile; E·G. head, midbody, caudal end of

larva; H-J. heads of metamorphic, early and late juvenile forms; K-N. stages In the development of stomach, liver, airbladder, and gall bladder from larval to juvenile

stages. Abbreviations: AB, air bladder; ES, esophagus; GB, gall bladder; IN, intestine; LR, liver; OP, opisthonephros, ST, stomach.

16
120· 110· 90· BO·

Bathycongrus macrurus

30· • larvae 30·

... metamorphic forms

• juveniles

• adults

B. varidens

o larvae

20· ojuveniles 20·

o adults

10· 0

• 0 • • 0 • ••

O·

120· 110· 100· 90·

Figure 12.-Distribution of Bathycongrus macrurus and B. varidens based primarily on SIO collections.

Distribution (Fig. 12).-The few larvae collected (only 62)

occur from the Gulf of California to Panama in the months of

February, May, June, and August; the maximum number obtained

was 26 in June. Metamorphic forms were collected in July, and

juveniles were collected in January.

Bathycongrus varidens (Garman) 1899

Figures 7I-L, 12

Literature.-Garman (1899) described Uroconger varidens

from the Pacific coast of Panama. A study of the dentition and

anatomy of the juveniles and adults shows that the species is referable to Bathycongrus.

Identification.-The larvae were identified with the help of a

juvenile (136.0 mm) and an adult (234.0 mm) which retained the

characteristic pigmentation. The larval and juvenile pigmentation

is in the form of three parallel rows on the lateral side. The

myotomal counts (158-162) of the five larvae do not quite agree

with the vertebral counts, (38-41) + (109-115) = 147-156, due

to broken tails of the adults. Similar larvae with three lateral rows

of melanophores were referred to Congrina (Rhechias) by Castle

(1969a) and to Rhechias by Smith (1971). The upper and lower

rows are double rows in B. varidens, whereas they are single in

Rhechias spp.

Material Examined.-Seven specimens, 154-250 mm TL.

Gulf of California: SIO 68-132(1), 68-128(1), 63-852(1),

63-8333(1),75-214(2), NMFS ETP 11.072(1).

Description (based on 5 specimens, 154-250 mm TL).-Body

elongate; a double row of circular melanophores on lateral side

close to dorsal region of body and a similar row close to ventral

17

region; a third double row in midlateral line; a single row on

mid ventral region; a series of closely packed, small melanophores

at base of median fin rays; a row of three melanophores in heart

region and at angle of jaw; a crescentic patch above and below

eye. Preanal distance 93-96%; predorsal distance 71-96%; head

4-5%; greatest depth 10-14%; total myotomes 158-162; preanal

myotomes 136-143; last blood vessel at myotomes 54-56; caudal

fin rays 5 + 5 = 10; tooth formula 1+8+(12-25)

1+(6-9)+(7 -9)

Metamorphic Forms and Juveniles (Table 1).-Three double

rows of melanophores on the side of the body are retained to the

juvenile stage and even to the adult stages (240.0 mm) to some

degree. Juvenile pigmentation appears as fine brown dots all over

the body and margin of the median fins. Part of the esophagus and

stomach become black.

The reduction (54.4%) in total length is high, and that of the

body depth (6.3%) is moderate. The increase (16.5%) in the head

length is the highest.

Distribution (Fig. 12).-The larvae are rare (only five) and

were collected in the months of February, April, and May in the

offshore waters from Guatemala outwards. The juveniles and

adults were collected from the Gulf of California to Panama in

January.

Discussion.-The characteristics of the species varidens do not

agree with those of Uroconger. The body is robust and the

vomerine teeth are a triangular patch, not uniserial as in

Uroconger. The stomach is black as in Bathycongrus, whereas it is

unpigmented in Uroconger, which also has a very high (over 200)

myotomal count.
ACKNOWLEDGMENTS

I thank Richard H. Rosenblatt and the late Elbert H. Ahlstrom

for their guidance, encouragement, and assistance during the

course of this work. My special thanks are due to David G. Smith

for critically reading the manuscript and suggesting many

changes. I am grateful to the late John D. Isaacs for the award of

the Postdoctoral Fellowship from the Marine Life Research Group

funds during the tenure in which the major part of this work was

carried out. My thanks are also due to Joseph L. Reid and Richard

Schwartzlose for providing a Research Fellowship for 2 mo from

the Marine Life Research Group to complete this work. I thank

the late Carl L. Hubbs, Laura C. Hubbs, and Elizabeth Shor for

their assistance, and also for use of the excellent personal library

of Carl L. Hubbs.

Thanks are also due to the following persons and institutions for

the loan of specimens and for providing space, assistance, and

information: R. J. Lavenberg, Los Angeles County Museum of

Natural History; Robert D. Harwood and John E. Bleck, University of California at Los Angeles; B. G. Nafpaktitis, University of

Southern California; John D. Fitch, California Department of Fish

and Game; Joseph E. Copp and Jane B. Pulsifer, Scripps Institution of Oceanography; William N. Eschmeyer and John E.

McCosker, California Academy of Sciences; Robert H. Gibbs, JT.

and Robert H. Kanazawa, U.S. National Museum of Natural

History; John H. Ryther, Woods Hole Oceanographic Institution;

P. H. Greenwood, British Museum of Natural History; and H.

Asano, Kyoto University. I thank Cherie Wetzel of City College

of San Francisco and Mark W. Lee of Simpson College for their

encouragement in the pursuit of my research interest. Finally, I

thank Charles D. Cox and my wife, Jessy Raju, for helping me in

many ways to finish this manuscript. This paper is a contribution

of the Scripps Institution of Oceanography.

LITERATURE CITED

ASANO, H.

1962. Studies on the congrid eels of Iapan. Bull. Misaki Mar. BioI. lnst.,

Kyoto Univ. I: 1-143.

BLACHE, I.

1977. Leptocephales des poissons anguilliformes dans la zone sud du Golfe de

Guinee. Faune Trop. O.R.S.T.O.M. 20, 381 p.

CASTLE, P. H. I.

1963. The systematics, development and distribution of two eels of the genus

Gnalhophis (Congridae) in Australasian waters. Zool. Publ., Victoria Univ.,

Wellington 34:1-47.

1964. Congrid leptocephali in Australasian waters with descriptions of

Conger wilsoni (BI. and Schn.) and C. verreauxi Kaup. Zool. Publ., Victoria

Univ., Wellington 37:1-45.

1966. Die ichthyologische Ausbeute der ersten Westafrika-Fahrt des fischereitechnischen Forschungsschiffes "Walther Herwig." 3. The eel larvae

(leptocephali). Arch. Fischereiwiss. 17(1): 19-35.

1968. Larval development of the congrid eel Gnathophis capensis (Kaup), off

Southern Africa, with notes on the identity of Congermuraena australis

Barnard. Zool. Afr. 3(2):139-154.

1969a. The eel genera Congrina and Coloconger off Southern Mozambique

and their larval forms. Dep. Ichthyol., Rhodes Univ., Spec. Publ. 6, lOp.

1969b. Eggs and early larvae of the congrid eel Gnathophis capensis off

Southern Africa. Dep. Ichthyol., Rhodes Univ., Spec. Pub1. 5, 5 p.

1970. Ergebnisse der Forschungsreisen des FFS "Walther Herwig" nach SudAmerika. Xl. The leptocephali. Arch. Fischereiwiss. 21:1-21.

CASTLE, P. H. I., and D. A. ROBERTSON.

1974. Early life history of the congrid eels Gnathophis habenatus and G.

incognitus in New Zealand waters. N.Z. I. Mar. Freshwater Res. 8:95-1 10.

COWAN, G. I. MeT., and R. H. ROSENBLATT.

1974. Taenioconger canabus, a new heterocongrin eel (Pisces: Congridae)

from Baja California, with a comparison of a closely related species.

Copeia 1974:55-60.

18

D'ANCONA, U.

1931. Uova, larve e stadi giovanili di teleostei. Fauna Flora Golfo Napoli,

Monogr. 38:94-156.

EIGENMANN, C. H.

1902. The egg and development of the conger eel. Bull. U.S. Fish. Comm.

21:37-44.

FITCH, I. E., and R. I. LAVENBERG.

1968. Deep-water teleostean fishes of California. Univ. Calif. Press,

Berkeley, 155 p.

GARMAN, S.

1899. Reports on an exploration off the west coasts of Mexico, Central and

South America, and off the Galapagos Islands, in charge of Alexander

Agassiz, by the U.S. Fish Commission Steamer "Albatross," during 1891,

Lieut. Commander Z. L. Tanner, U.S.N., commanding. Mem. Mus. Compo

Zool. Harv. 24, 431 p.

GILBERT, C. H.

1891. Scientific results of explorations by the U.S. Fish Commission Steamer

"Albatross." No. XXI - Descriptions of apodal fishes from the tropical

Pacific. Proc. U.S. Natl. Mus. 14:347-352.

GINSBURG,1.

1951. The eels of the northern Gulf Coast of the United States and some

related species. Tex. I. Sci. 3(3):431-485.

GOODE, G. B., and T. H. BEAN.

1896 (1895). Oceanic ichthyology. Smithson. Inst. Spec. Bull., 533 p.

GRASSI, G. B.

1913. Metamorfosi dei maraenoidi. Ricerche sistematiche ed ecologische.

lena: Fischer, 211 p.

IORDAN, D. S., and C. H. BOLLMAN.

1890. Descriptions of new species of fishes collected at the Galapagos Islands

and along the coast of the United States and Colombia, 1887-88. Proc. U.S.

Natl. Mus. 12:149-183.

IORDAN, D. S., and B. W. EVERMANN.

1896. The fishes of North and Middle America. U.S. Natl. Mus. Bull. 47(1):

951-953.

1927. New genera and species of North America fishes. Proc. Calif. Acad.

Sci., Ser 4, 16:501-507.

IORDAN, D. S., and C. H. GILBERT.

1883. List of a collection of fishes made by Mr. L. Belding near Cape San

Lucas, lower California. Proc. U.S. Natl. Mus. 5:378-381.

KANAZAWA, R. H.

1961. Paraconger, a new genus with three new species of eels (family Congridae). Proc. U.S. Natl. Mus. 113:1-14.

LEA, E.

1913. Muraenoid larvae. Rep. Sci. "Michael Sars" North Atl. Deep-sea

Exped. 1910. Bergen Mus., Bergen, 1933 ed. 3(1):1-48.

MEEK, S. E., and S. F. HILDEBRAND.

1923. The marine fishes of Panama. Field Mus. Nat. Hist., Publ. 215. Ser.

15, Part 1,330 p.

MYERS, G. S., and C. B. WADE.

1941. Four new genera and tcn new species of eels from the Pacific Coast of

tropical America. Allan Hancock Found. Pac. Exped. 9:65-111.

NAPLIN, N. A., and C. L. OBENCHAIN.

1980. A description of eggs and larvae of the snake eel, Pisodonophis cruen·

tifer (Ophichthidae). Bull. Mar. Sci. 30:413-423.

NORMAN, I. R.

1925. A new eel of the genus Congromuraena from Tobago, with notes on C.

balearica and C. opislhophlhalmus. Ann. Mag. Na!. His!., Ser. 9, 15:213-

314.

OGILBY, I. D.

1898. New genera and species of fishes. Proc. Linn. Soc. N.S.W. 23:280-

299.

PELLEGRIN, I.

1923. Le Taenioconger digueti Pellegrin, poisson apode du Golfe de Californie. Bull. Mus. Nat. Hist. Nat. 29:236-237.

RAIU, S. N.

1974. Distribution, growth, and metamorphosis of leptocephali of the garden

eels, Taenioconger sp. and Gorgasia sp. Copeia 1974:494-500.

ROSENBLATT, R. H.

1958. The status and synonomy of the eastern Pacific eel Ariosoma gilberti

(Ogilby). Copeia 1958:52-54.

1967. The osteology of the congrid eel Gorgasia puncrara and the relationships of the Heterocongrinae. Pac. Sci. 21 :91-97.

SMITH, D. G.

1971. Osteology, and relationships of the congrid eels of the western North

Atlantic (Pisces, Anguilliformes). Ph.D. Thesis, Univ. Miami, 163 p.

1979. Guide to the leptocephali (Elopiformes, Anguilliformes, and Notacanthiformes). U.S. Dep. Commer., NOAA Tech. Rep. NMFS Circ. 424, 39 p.
SMITH, D. G., and R. H. KANAZAWA.

1977. Eight new species and a new genus of congrid eels from the western

North Atlantic with redescriptions of Ariosoma analis, Hildebrandia guppyi

and Rhechias vicinalis. Mar. Sci. 27:530-543.

SNYDER, G. H., and A. FLEMINGER.

1965. A catalogue of zooplankton samples in the marine invertebrate collections of Scripps Institution of Oceanography. SIO Ref. No. 65. 14:1-140.

1972. A catalogue of zooplankton samples in the marine invertebrate collections of Scripps Institution of Oceanography. Accessions, 1965-70. SIO

19

Ref. No. 72-68, p. 1-170.

THOMOPOULOS, A.

1956. Sur quelques oeuf planctoniques de teleosteens de la Baie de Villefranche. II. Poches du mois de Septembre. Bull. Inst. Oceanogr. Monaco

1072:1-10.

WADE, C. B.

1946. Two new genera and five new species of apodal fishes from the eastern

Pacific. Allan Hancock Found. Pac. Exped. 9:181-202.