Variation in the

Western Atlantic Clinid Fish

Malacoctenus triangulatus with a

Revised Key to the

Atlantic Species of Malacoctenus

VICTOR G. SPRINGER

and

MARTIN F. GOMON

m

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 200
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SMITHSONIA N CONTRIBUTION S TO ZOOLOGY • NUMBER 200

Variation in the

Western Atlantic Clinid Fish

Malacoctenus triangulatus with a

Revised Key to the

Atlantic Species of Malacoctenus

Victor G. Springer

and Martin F. Gomon

SMITHSONIAN INSTITUTION PRESS

City of Washington

1975
ABSTRACT

Springer, Victor G., and Martin F. Gomon. Variation in the Western Atlantic

Clinid Fish Malacoctenus triangulatus with a Revised Key to the Atlantic Species

of Malacoctenus. Smithsonian Contributions to Zoology, number 200, 11 pages, 3

figures, 3 tables, 1975.—Malacoctenus triangulatus occurs along the shallow coastlines of the Caribbean Sea, southwestern Gulf of Mexico, southern Florida, Bahama

Islands, Fernando de Noronja and Bahia, Brazil. Data on meristic characters and

their variation are reported for many populations of M. triangulatus. The species

is highly variable but shifts in means for various meristic characters tend to follow a geographic pattern; however, several of the means for the Trinidad and

Venezuela populations stand out from those of nearby populations. A key is given

to the Atlantic species of Malacoctenus, following Springer (1958), but employing

additional characters.

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded

in the Institution's annual report, Smithsonian Year. SI PRESS NUMBER 5335. SERIES COVER

DESIGN: The coral Montastrea cavernosa (Linnaeus).

Library of Congress Cataloging in Publication Data

Springer, Victor Gruschka, 1928-

Variation in the western Atlantic clinid fish.

(Smithsonian contributions to zoology, no 200)

Supt. of Docs, no.: SI 157:200

1. Saddled blenny. 2. Malacoctenus. 3. Marine fishes—Atlantic Ocean. I. Gomon, Martin F.,

joint author. II. Title. III. Series: Smithsonian Institution. Smithsonian contributions to

zoology, no. 200.

QL1.S54 no. 200 [QL638.C63] 591'.08s [597'.58] 74-32385
Variation in the

Western Atlantic Clinid Fish

Malacoctenus triangulatus with a

Revised Key to the

Atlantic Species of Malacoctenus

Victor G. Springer

and Martin F. Gomon

Introduction

Springer (1958)

 x described Malacoctenus triangulatus. He had too few specimens to permit

analysis of geographic variation. Since 1958, numerous specimens of Af. triangulatus from many

localities have become available. Study of these

specimens indicates that M. triangulatus is geographically variable. Reporting this variation is desirable, not only because it expands the description

of the species, but also because it represents the

most comprehensive account detailing meristic variation in a shorefish of the tropical western Atlantic.

The description of this variation can serve as a

basis for comparison with other, similarly distributed

species.

Early in our study we believed that we were

dealing with a complex of related, allopatric species,

but as analysis of our data progressed, the differVictor G. Springer, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution,

Washington, D.C. 20560. Martin F. Gomon, University of

Miami, Rosenstiel School of Marine and Atmospheric Sciences, Miami, Florida 33149.

aThe date of publication on the serial is December 1958,

but the journal was not actually mailed until sometime in

June 1959.

ences separating the supposed species decreased. It

may well be that other presently recognized, closely

related, allopatric species of tropical western Atlantic shorefishes may be synonymized when more

complete geographic representation of the species is

available.

INSTITUTIONAL ABBREVIATIONS.—The following

abbreviations denote the institutions that furnished

the additional material for the present study:

AMNH= American Museum of Natural History,

New York City; ANSP=Academy of Natural Sciences of Philadelphia; FAU = Florida Atlantic University, Boca Raton; FMNH = Field Museum of

Natural History, Chicago; FSM = Florida State Museum, Gainesville; GCRL=Gulf Coast Research

Laboratory, Ocean Springs, Mississippi; LACM =

Los Angeles County Museum of Natural History;

UMML=Rosenstiel School of Marine and Atmospheric Sciences, University of Miami; USNM = National Museum of Natural History (formerly in

United States National Museum), Smithsonian

Institution.

ACKNOWLEDGMENTS.—For the loan or gift of

specimens we extend our appreciation to C. L.

Smith (AMNH), J. E. Bdhlke (ANSP), W. R.

Courtenay, Jr. (FAU), C. R. Gilbert (FSM),

D. W. Greenfield (Northern Illinois University),

1
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

C. E. Dawson (GCRL), R. J. Lavenberg (LACM),

C R. Robins (UMML), and F. Cervigon (Universidad de Oriente, Porlamar, Venezuela).

A. George, University of Maryland, assisted in

the recording of data; F. J. McKinney and E. N.

Gramblin (USNM) made many of the radiographs.

The manuscript benefited from critical reviews

by J. E. Bohlke, C. R. Robins, and W. R. SmithVaniz, and from discussions with B. B. Collette,

T. H. Fraser, and R. H. Gibbs, Jr. Some of these

colleagues disagreed with certain of the speculations that appear in the text. The senior author

takes full responsibility for all subjective matter

that this study includes.

the Central American coast. Fernando de Noronja

and Bahia, Brazil, followed at the end. Because

of the coastline's circularity we could have begun

the sequence of localities with almost any locality.

No arrangement was completely satisfactory in reflecting the trends of the means. Plotting the means

for the various characters on maps (which we did)

has some advantages that are helpful in interpreting the data, but also has disadvantages in presenting the data in publication. We have also

presented the means of several characters graphically (Figure 2). This method enables one to

compare at a glance how several characters correlate, and also how the means shift for each character.

Methods

Fin-ray and scale counts based on specimens reported by Springer (1958) are incorporated with

those taken from the new material (see "Material

Examined"). Fin-ray and vertebral counts on the

new material were taken from radiographs. Fin-rays

were counted following the methods of Springer

(1958) with the following exception: wherever a

dorsal- or anal-fin pterygiophore appeared without

a corresponding fin ray, the ray was counted as being present. Such "blank" pterygiophores occurred

in only 11 of the approximately 500 specimens

examined by radiograph. We do not believe, therefore, that combining Springer's original counts,

from approximately 150 specimens, with the new

counts has affected the averages or our conclusions

based on them.

Only caudal vertebrae are reported; the first

caudal vertebra is the anteriormost vertebra bearing a hemal spine. There are consistently 10 precaudal vertebrae in M. triangulatus.

Cirri counts include the number of free cirri tips

(the cirri are normally simple, but where branched

each branch was counted). The number of cirri

increases slightly with size but appears to stabilize

at about 30 mm SL. For this reason we include

counts of only those specimens 30 mm SL or larger.

In Tables 1-3 and Figure 2 the localities

were arranged in a geographic sequence intended

to reflect the essentially circular configuration of

the coastline where M. triangulatus occurs. We began with Florida and the Bahamas in the north,

progressed south, then east, south, west (along

northern South America) and, finally, north along

Distribution

Malacoctenus triangulatus occurs in the clear,

shallow (to about 10 meters), tropical-subtropical

waters of the western Atlantic from the northern

Bahamas south to Bahia, Brazil (Figure 1). Rocks

and corals are almost always, if not always, a dominant feature of its habitat. The absences of the

species on the northern coast of South America

between Trinidad and Fernando de Noronja and

from all but the southwestern portion of the Gulf

of Mexico are undoubtedly real and probably result from a lack of suitable habitat in these areas.

Many of the reef-fish species of the Caribbean

region are also absent from these same areas. The

apparent absence of M. triangulatus from other

long expanses of Caribbean coast (for instance,

between Cubagua, Venezuela, and Santa Marta,

Columbia; from western Cuba to eastern Hispaniola) probably indicates lack of collecting.

There is little known about the life history of

M. triangulatus that might contribute toward an

understanding of its distribution, for instance,

whether it has pelagic stages during its life history.

Even if it does not, the adults might be wafted. If

the species owes its distribution to the prevailing

ocean currents, it probably entered the Caribbean

from the Brazilian coast and spread west and northward. Fernando de Noronja lies in the path of the

South Equatorial Current, which flows east to west.

This current splits at the eastern hump of South

America and sends branches flowing both south

along the Brazilian coast and northwest into the

Caribbean. Currents in the Caribbean generally

flow westward from the Lesser Antillean chain. A
NUMBER 200

60°

100°

FIGURE 1.—Distribution of Malacoctenus triangulatus based on specimens examined.

gyre forms along the Panamanian coast, but the

major flow passes north through the Yucatan channel and continues both northwestward into the

Gulf of Mexico and northeastward through the

Straits of Florida and up the coast of Florida (the

Gulf Stream). There is also a prevailing northwestward flowing current, extending from the northern

Lesser Antilles, that skirts the eastern coasts of the

Bahama Islands. In this scheme there would be

little chance for the northern populations to furnish

colonizers to the south.

Malacoctenus triangulatus, however, may have

had a more continuous distribution along the northeastern coast of South America in past geologic

periods. If so the Fernando de Noronja and

Brazilian populations would represent relict populations. There is some divergence, particularly in

color pattern, exhibited by both of these southernmost populations, and one or both may be expected

to speciate ultimately. If, however, the prevailing

currents do carry introductions of M. triangulatus

from these southern populations into the Caribbean,

complete differentiation of the southern populations, as distinct from the northern populations,

may never transpire.

Results

Our findings can, for the most part, be derived

by examination of Tables 1-3 and Figure 2, where

the shifts and trends of the means for meristic

characters are readily observable. The Trinidad and

Venezuelan populations stand out for their high

numbers of dorsal-fin spines, total dorsal-fin elements and caudal vertebrae, and relatively high

numbers of nape cirri. These two populations
TABLE 1.—Frequency distributions for certain meristic characters of Malacoctenus triangulatus

Locality

FLORIDA

Brouard County

Monroe County

BAHAMAS

Green Turtle Cay

Bimini

New Providence

Eleuthera

Andros

San Salvador

Cay Sal Bank

Little Inagua

Great Inagua

CUBA

MISTERIOSA BANK

GRAND CAYMAN

JAMAICA

PUERTO RICO

S T. THOMAS

ANGUILIA

S T. BARTHELEMY

ANTIGUA

DOMINICA

MARTINIQUE

S T. LUCIA

BEQUIA

LITTLE ST. VINCENT

BARBADOS

GRENADA

TOBAGO

TRINIDAD

VENEZUELA

COLOMBIA

PANAMA

ALBUQUEQUE CAY

COURTOWN CAY

OLD PROVIDENCE

BELIZE

MEXICO

Banco Chinchorro

Cayos Arcos

Vera Cruz

FERNANDO DE HORONJA

BRAZIL (Bahia )

Dorss

18 19

4

1

2

1

1

1 2

1

1

3

1

1

4

4

1

1

1 4

l-fin

2 0

26

2 1

14

3

75

8

14

It

2

36

11

2

1

22

5

6

5

1

16

22

17

I

37

1

3

4

18

17

2

1

9

1

15

1

55

2

7

2

59

18

Spines

2 1

3

1

1

1*

1

1

1

1

1

1

2

1

( •

24

16

1

1

1

X

20.1

20.0

20.1

20.0

20.0

19-9

19.8

20.0

20.0

20.0

20.0

20.0

19-9

19.8

19.8

20.0

19.9

20.0

20.0

20.0

20.0

19.5

20.0

20.2

20.1

20.3

21.0

20.9

19.7

20.0

20.0

19.7

20.0

19.7

19.9

20.0

Segmented

1 0

1

1

1

1

1 1

1 0

3

0

3

13

5

1

1 1

1*

1

3

2

4

1

12

16

14

2

31

1

3

4

18

2 1

2 2

13

5

5

18

11

15

Dorsal-fin

12

19

18

9

66

9

11

3

2

27

9

2

22

4

7

1

8

6

4

1

7

1

1

3

2

3

5

1

8

1

10

1

4 l

3

7

3

53

4

13

1

It

1

1

1

1

Rays

X

11.6

11.9

11.6

11.0

11.4

12.0

11.8

11.8

12.0

11. T

11.7

12.0

11.9

11.7

12.0

11.2

11.4

11.3

11.2

11.0

11.2

11.5

11.0

11.2

11.1

11.1

11.1

11.3

11.6

11.7

11.7

12.0

12.0

12.0

11.8

11.2

Total

29 30

1

2

1

1

Dorss

31

7

2

5

3

12

1

5

1

12

4

1

2

3

1

4

1

10

16

13

2

31

2

3

3

18

17

1

1

9

5

2 1

1

1

15

15

l-fin

32

22

19

10

69

8

12

3

2

25

9

2

23

3

6

1

8

6

5

1

8

2

4

4

22

13

1

4

1

10

1

37

2

7

2

47

3

Elements

33

1

2

1

2

3

4

2

2

1

X

31.8

32.0

31.7

31.0

32.0

31.9

31.7

31.8

32.0

31.7

31.7

32.0

31.8

31.5

31.8

31.2

31.3

31.3

31.3

31.0

31.2

31.0

31-0

31.4

31.2

31.3

32.1

32.2

31.3

31.7

31.7

31.7

32.0

31.7

31.8

31-3

Segrasnted

18 19 20

6

3

3

2

12

3

10

7

1

1

1 - -

2

4

3

1

14

2 16

14

4

36

2

3

2

1 20

15

3

1

1

1 0

5

17

1

2

25

16

Anal2 1

2 1

18

11

1

67

9

15

4

2

26

5

1

24

4

3

1

6

4

1,

2

3

1

5

23

14

3

1

9

1

4 l

2

7

1

38

3

fin Ra

22

2

3

2

1

2

1

y s

X

20.9

20.8

20.8

20.3

20.9

21.0

20.8

21.0

21.0

20.8

20.5

20.5

20.9

20.7

20.4

20.2

20.3

20.1

20.2

20.0

20.0

20.0

20.0

20.6

20.0

20.2

20.9

21.0

20.2

20.6

20.7

20.7

21.0

20.3

20.6

20.2

TABLE 2.—Frequency distributions

Locality

FLORIDA

Broward County

Monroe County

BAHAMAS

Green Turtle Cay

Binini

New Providence

Eleuthera

Androj

San Salvador

Cay Sal Bank

Little Inagua

Great Inagua

CUBA

MI5TEHI0SA BANK

GRAND CAYMAN

JAMAICA

PUERTO RICO

S T. THOMAS

ANGUILLA

S T. BARTHELEMY

ANTIGUA

DOMINICA

MARTINIQUE

S T. LUCIA

BEQUIA

LITTLE ST. VINCENT

BARBADOS

GREHADA

TOBAGO

TRINIDAD

VENEZUELA

COLOMBIA

PANAMA

ALBUQUERQUE

COURTOWN CAY

OLD PROVIDENCE

BELIZE

MEXICO

Binco Chichorro

Cayos Arcos

Vera Cruz

FERNANDO DE NORONJA

BRAZIL (Bahla )

26

1

:

1

1

3

1

1

2

1

3

3

2

2

It

1

k

1

.

r

:

2

Cauds

27

26

16

14

3

35

9

16

2

30

L2

24

U

1

5

1

15

19

15

2

34

3

It

17

16

U

5

1

9

1

11

1

46

2

31

15

1 Vertebrae

28 29

2

1

1

2

1

4

1

1

1

1

1

4 1

2 1

1:

6

4

X

27.0

27-0

27.1

27.0

27.0

27.0

27-0

27.0

27.0

26.9

27.0

26.7

26.5

27. 3

26. )

26.9

26.9

26.5

26.9

27.0

27.2

26.9

27.2

27.3

27.7

26.7

26.7

27-0

26.7

27.1

26.9

for certain meristic characters of

50 51

1

1 1

1

3

52

1

1

1

2

1

3

6

1

3

5

53

4

-

-

1

2

4

5

10

1

It

2

4

4

1

3

54

6

3

1

1

2

4

2

3

2

7

.

2

3

5

2

1

1

1

5

.

1

1

Laters

55

2

1

3

7

1

4

4

.

1

1

6

3

4

1

3

1

1

1

2

3

5

3

it

1

1

5

6

1-line

56

It

6

1

14

1

2

7

5

3

1

1

4

1

_

2

It

6

2

1

2

8

3

Malacoctenus triangulatus

Scales

57

1

3

17

2

5

1

2

4

1

1

5

3

1

1

.

1

1

6

1

1

1 1

58

5

14

.

3

2

10

3

6

3

1

2

1

2

8

59

4

1

1

-

7

5

60

3

1

1

1

2

4

61 62

1

1

1 1

X

5^-5

55.O

56.8

57-1

57.0

56.7

58.O

57.O

57.1

58.O

57.5

54.8

55-2

54.4

54. 1

5*-3

53-5

53-5

55-7

52-9

5

54.H8

5 ^ 5

52.6

55-1

55-5

55.0

55-3

57-1*

52.0
NUMBER 200

TABLE 3.—Total number of nape cirri (both sides) in specimens, 30 mm SL and larger, of

Malacoctenus triangulatus

Locality

FLORIDA

Broward County

Monroe County

BAHAMA. S

Green Turtle Cay

New Providence

Eleuthera

Andros

Cay Sal Bank

Little Inagaa

Great Inagaa

MISTERIOSA BANK

GRAND CAYMAN

JAMAICA

PUERTO RICO

ST. THOMAS

ANGUILLA

ST. BARTHELEMY

ANTIGUA

DOMINICA

MARTINIQUE

ST. LUCIA

BEQUIA

LITTLE ST. VINCENT

GRENADA

TOBAGO

TRINIDAD

VENEZUELA

PANAMA

COURTOWN CAY

BELIZE

BUNCO CHINCHORRO

FERNANDO DE NORONJA

BRAZIL (Bahia)

8 9 10

1 1 1

1

1

1 1

1

11

2

2

1

1

1

2

-

2

1*

12

9

1*

2

-

1

1

5

-

-

1

8

1

13

9

6

1

1

-

5

i

h

1

-

3

1

7

1

14

h

5

5

11

3

5

1

12

5

9

1

2

1

1

1

2

19

1

19

13

15

1

3

5

1

2

6

3

1*

1

1

-

1

1

1

4

2

16

4

3

2

5

5

1

2

-

2

-

1

1

3

2

1

3

1

1

2

17

1

1

1

2

1

2

3

-

2

3

It

2

-

1

13

1

1

1

1

1

2

5

1

.

5

2

8

1

19

-

1

1

-

-

-

2

4

1

-

20 21 22 23

1

2

1

2

1 - - 1

5

2 1

2

2

1

24 25 26 x

12.3

12.7

14.9

14.4

14.4

15-4

13.0

14.5

14.1

12.7

15-3

16.0

16.3

18.2

19-5

17.6

1 22.0

19.7

18.4

17.1

18.2

16.4

18.0

15-5

14.2

14.5

13-1

13.9

misled us initially into believing that we were

working with a complex of species. However, it can

be noted that there is a slight trend toward higher

mean numbers of the same meristic characters in

the northern populations—particularly those of

Barbados and Tobago, and to a much lesser degree,

Grenada—that are nearest to Trinidad and Venezuela.

Aside from the Trinidad and Venezuelan populations, the means, except for nape cirri, tend to be

highest in the northernmost, lower in the northwesternmost, and lowest in the eastern (Lesser.

Antilles) populations.

The means for the Fernando de Noronja and

Bahia populations are not close for most characters,

and there is no overlap in the ranges for lateral-line

scales between these two populations. In no

character, however, do these two populations stand

out from the Caribbean populations.

Springer (1958) reported meristic variation in

dorsal- and anal-fin rays in the Caribbean populations of Labrisomus nuchipinnis and Malacoctenus gilli. The shifts in averages for the various

populations of these two species show little relationship to each other or to those of M. triangulatus.

A re-evaluation of variation in L. nuchipinnis and

M. gilli, based on the greater amount of material

now available, perhaps would provide a more

meaningful basis for comparison with M. triangulatus.

COLOR PATTERN OF PRESERVED SPECIMENS.—Although there is much variation in color pattern

within all populations of M. triangulatus, some

populations exhibit differences in pigmentation

that are shared by many or most individuals of the

same population. For example, sexual dichromatism is usually marked in specimens from the

northern and western portions of the species' range

(Florida south to northern Lesser Antilles; Central

America). Males possess rather uniformly dark, triangular saddle markings on the body, which often

have irregularly intensified anterior and posterior

margins. The marginal intensifications may be

present as poorly defined spots, which are never a

prominent feature of the color pattern. In females

(Figure 3a) the saddle markings may be less

prominent and less well defined than in males, and

often enclose small irregular, pale marks, which

are rarely present in males. Marginal intensifications of the saddles are usually even less obvious
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

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FIGURE 2.—Graphs of means for certain meristic characters in populations of Malacoctenus
NUMBER 200

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BRAZIL

FERNANDO DE NORONJA

VERA CRUZ

CAYOS ARCOS

BANCO CHINCHORRO

BELIZE

OLD PROVIDENCE

COURTOWN CAY

ALBUQUERQUE CAY

PANAMA

COLOMBIA

VENEZUELA

TRINIDAD

TOBAGO

GRENADA

BARBADOS

LITTLE ST. VINCENT

BEQUIA

ST. LUCIA

MARTINIQUE

DOMINICA

ANTIGUA

ST. BARTHELEMY

ANGUILLA

ST. THOMAS

PUERTO RICO

JAMAICA

GRAND CAYMAN

MISTERIOSA BANK

CUBA

GREAT INAGUA

LITTLE INAGUA

CAY SAL BANK

SAN SALVADOR

ANDROS

ELEUTHERA

NEW PROVIDENCE

BIMINI

GREEN TURTLE CAY

MONROE COUNTY

BROWARD COUNTY

CN r-l O CT» 00

triangulatus based on information in Tables 1-3. (Stars represent counts for single specimens.)
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

a

FIGURE 3.—Malacoctenus triangulatus, females; a, ANSP 74341, 43.3 mm SL, Hog Island (vicinity

of New Providence), Bahamas; b, USNM 198134, 53.4 mm SL, Chupara Pt., Trinidad (innermost

pelvic-fin ray not visible externally); c, GCRL 1576, 36.1 mm SL, Bahia, Brazil. (Drawn by

J. R. Schroeder.)
NUMBER 200

in females than males. Both sexes usually possess

indications of dusky to dark areas in the pale spaces

between the ventral ends of the saddles, but dark

markings more dorsally in the interspaces occur

more often in females. Males often lack dark spots

posteriorly in the dorsal, anal, and caudal fins, but

when the spots are present they are usually not

as well developed as they are in females. An obvious

dark mark on the body at the base of the anterior

dorsal-fin spines that extends onto the fin basally

is usually present in all specimens but may be more

prominent in females than in males. The ventrolateral sides of the head in both sexes are usually

pale with few prominent markings, and transverse

bands beneath the head, when present, are approximately uniform in width and dusky.

There appears to be a change, perhaps gradual,

from the northern type color pattern to another

type that is found in the Lesser Antilles as far south

as Trinidad and Venezuela. In specimens from

Grenada, Trinidad, and Venezuela, for instance,

sexual dichromatism, although present, is not always as obvious as in the more northern specimens,

but is manifested by a generally darker overall

coloration of males. Females (Figure 36) have a

much paler background color and, consequently,

appear to have a more contrasting saddle pattern.

The dark marginal spots of the saddles of females

are more obvious than are those of males, and females have considerable numbers of irregular, dark

spots along the ventral portion of the body, which

are reduced or absent in males. Females often

have darkly spotted, narrow, transverse bands on

the underside of the head, which are faint and

diffuse, at best, in males. The dorsal fin of females

is marked with continuations of the body saddles

basally along its anterior half, and the base of the fin

is mostly free of pigment posteriorly. The dorsal

fin of males is almost without pigment anteriorly

and exhibits a diagonal banding posteriorly. Conversely, females possess banded anal and caudal fins,

whereas those of males are overall dusky, although

the caudal of males may be faintly banded. The

dark mark anteriorly on the base of the dorsal fin

is present in many of the Grenada specimens but

is much less developed or absent in the Trinidad

and Venezuelan specimens. Some females we have

seen from Florida are indistinguishable from the

southern females, but we have not found similar

overlap with males from the two areas.

The body color pattern of both sexes from

Fernando de Noronja approaches that of males

from the northern areas, but the intensified spots

on the margins of the body saddles are, in contrast,

prominent. In addition, the intensified dark

blotches between the ventral tips of the body saddles, together with the tips of the saddles, form a

distinct horizontal row of large, irregular spots.

There is little or no development of the dark

mark anteriorly at the base of the dorsal fin. The

anal fin is transparent to dusky. The underside of

the head is traversed by several rows of small, dark

spots or narrow, faint to dark lines. Males have no

spots, or only faint spots, in the dorsal fin, whereas

all females have prominent spots in this fin.

In specimens from Bahia, Brazil, sexual dichrcn

matism appears as a reverse bicoloration or intensification of pigment on the dorsal and ventral

halves of the body: males are darkest ventrally and

females (Figure 3c) dorsally. Although the dorsal

one-third of the body is usually darker than the

ventral two-thirds in all populations of M. triangulatus, this intensification appears to be slightly

more evident in females from Bahia. The body

saddles stand out less in the Bahia specimens due

to the complex dark, irregular spotting within the

saddles and in the pale spaces between the saddles,

particularly on the ventral half of the body.

Spotting is less distinct and fainter on males despite

the ventral intensification. Fine, dark spots anteriorly on the dorsal fin and banding posteriorly on

the dorsal and anal fins are better developed in

females than males. Both sexes have only faint

development of the dark mark anteriorly on the

dorsal fin. The ventral half of the head is often

traversed by narrow, dark bands in females, whereas

that of males is faintly marked at best.

Discussion

We are unable to explain fully the variation

we note among the populations of M. triangulatus.

Most probably the variations are the result of the

varying degrees of reproductive isolation exhibited

by the populations as influenced by complex ecological factors: temperature, light, water currents,

physiography. Hence consistent trends in meristic

characters should not be expected.

Often in fishes, high vertebral, scale and vertical
10 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

fin-ray counts are correlated with the higher or

lower latitudes as one progresses away from the

equator (Barlow, 1961, gives an illuminating review

of this subject). These correlations are also a reflection, but not necessarily a result, of decreasing

average annual water temperatures. The generally

high means for meristic characters of the northernmost populations of M. triangulatus conform with

the temperature-mean relationship, but the appearance of the highest means for some characters in

the Trinidad and Venezuelan populations, where

water temperatures average higher than at the

northern limits of the species' distribution (Bahamas), and the low means of the population at

Bahia, Brazil, where water tempertaures are similar

to those of the northernmost populations, do not.2

The fairly good correlation between high numbers of nape cirri and low numbers of lateral-line

scales in the various populations is readily apparent

on Figure 2. Inasmuch as both cirri and lateral-line

scales have sensory functions,3 one could infer that

the species is compensating for reduction in one

structure by increase in the other. We have no

information that would permit expanding on this

intriguing idea.

Springer (1958) reported that the prepectoral area

of M. triangulatus was scaled, with rare exceptions,

and that there was at least one scale in the midline

before the first dorsal-fin spine. We now find these

characters to be more variable than Springer reported. The absence or degree of scaling in the

prepectoral and predorsal areas is quite variable

within a population and can only be used with

qualification as key characters. Several colleagues

have mentioned to us difficulties in identifying specimens of M. triangulatus using Springer's earlier key,

which employed scalation. We, therefore, present a

new key to the Atlantic species of Malacoctenus,

which takes advantage of several characters not employed in the earlier key.

Key to the Atlantic Species of Malacoctenus

(Couplets 4-8 refer only to specimens 25 mm SL or larger)

1. Length of shortest pelvic-fin ray contained 4 or more times in length of longest; patch of

small teeth anteriorly behind outer row of large teeth in each jaw; ventral hypural plate

autogenous; pectoral-fin rays usually 15 Malacoctenus boehlkei

Length of shortest pelvic-fin ray contained less than 4 times in length of longest; small

teeth, when present, in single row behind outer row of large teeth in each jaw; ventral

hypural plate fused to urostylar centrum; pectoral-fin rays 14-17 2

2. Pectoral-fin rays typically 15-17; scales on prepectoral area, if present, about same size as those

on body; small teeth present behind outer row of large teeth in each jaw (extremely

difficult to see in Af. erdmani) 3

Pectoral-fin rays typically 14; scales on prepectoral area, if present, smaller than those on

body; small teeth not present behind outer row of large teeth in each jaw 4

3. Cirri on anterior nostril and above eye 2 (occasionally simple); pectoral-fin rays 15-17

(usually 16); prepectoral area without scales; small teeth behind large outer row 5 or less

in each jaw; distinct, dark blotch present at bases of posteriormost dorsal-fin spines; rarely

exceeding 30 mm SL Malacoctenus erdmani

Cirri on anterior nostril and above eye simple (occasionally 2); pectoral-fin rays 14-16

(usually 15); prepectoral area rarely without scales; small teeth behind large outer row

more than 6 in each jaw; no distinct, dark spot at bases of last dorsal-fin spines; commonly exceeding 40 mm SL Malacoctenus macro pus

4. Conspicuous, dark spot on anterior dorsal-fin spines and a dark ocellus dorsally on middorsal body contour extending dorsally onto posterior dorsal-fin spines; nasal + supraorbital + nape cirri = 6-10 on each side (nasal cirri 1; supraorbital cirri 2, with rare

exceptions; nape cirri 3-7); lateral-line scales 42-47 Malacoctenus gilli

Combination of conspicuous dark spot and ocellus on dorsal fin not present (many specimens of Af. triangulatus have a dark spot at the anterior end of the dorsal fin); nasal +

supraorbital + nape cirri = 10-47 (nasal cirri 2 or more, except simple in Af. africanus,

for which only one specimen was available, and rarely in Af. triangulatus and Af. aurolineatus); lateral-line scales 42-64 5

1

 Average surface water temperatures were inferred from

data presented in U. S. Naval Oceanographic Publication 700

and Charts II and III in Sverdrup, Johnson and Fleming

(1942).

*Ford (1959) reported that the cirri of Malacoctenus hubbsi

are variously supplied by branches of the fifth, seventh, and

tenth cranial nerves. On the basis of Ford's findings, a sensory

function for these cirri can be inferred.
NUMBER 200 11

5. Dorsal-fin spines 18-19 (rarely 19); total nasal cirri (both sides) 6-14 (usually more than

7); nape cirri 14-32 on each side; lateral-line scales 59-64; total vertebrae 34-36 (modally

35) Malacoctenus versicolor

Dorsal-fin spines 18-21 (rarely 18); total nasal cirri 2-6 (rarely more than 5); nape cirri

4-18 on each side; lateral-line scales 42-62; total vertebrae 35-39 (modally 36-38) 6

6. Supraorbital cirri 2 on each side; nape cirri 9-13 on each side; lateral-line scales 42-55;

dorsally projecting, short, bony point (hook) extending from dorsolateral margin of

cleithrum in many specimens (hook can be seen by lifting operculum); anterior two

dark bands on body often coalesced on dorsal portion of body, forming humeral blotch ... .

Malacoctenus aurolineatus

Supraorbital cirri 2-8 on each side (2 only in some specimens of M. triangulatus under

30 mm SL, which have fewer than 8 nape cirri, or unilaterally in rare specimens over 30

mm SL); nape cirri 4-18 on each side; lateral-line scales 48-62; no hook on cleithrum;

humeral blotch not present 7

7. Total nape cirri (both sides) 24-36; prepectoral area without scales; symphysial pores 1-6

(usually 3-4) Malacoctenus delalandei

Total nape cirri 8-26 (more than 21 in only 3 of several hundred specimens of M. triangulatus

examined); prepectoral area with or without scales; symphysial pores 1-3 (usually 1

or 2) 8

8. Segmented dorsal-fin rays 10; total nasal cirri (both sides) 2; preopercular series of pores not

extending onto operculum; prepectoral area scaled

Malacoctenus africanus (only 1 specimen available)

Segmented dorsal-fin rays 10-13 (10 in only 4 of several hundred specimens examined);

total nasal cirri 2-7 (2 in only 2 of several hundred specimens examined); preopercular

series of pores with 1 or 2 branches extending onto operculum; prepectoral area with

or without scales Malacoctenus triangulatus

Material Examined

(for additional material incorported in this study,

see Malacoctenus triangulatus in Springer, 1958)

FLORIDA: Broward County, FAU 71-21 (2), 71-22 (7),

71-63 (18), 72-19 (1); Monroe County, USNM 186168 (1).

BAHAMAS: Green Turtle Cay, UMML 5845 (5), 6508

(10); Bimini, UMML 10035 (3); Eleuthera, ANSP 100731 (5),

111904 (5); Andros: Pigeon Cays, UMML 1601 (12); Mastic

Cay, ANSP 100730 (6); Cay Sal Bank, ANSP 100733 (2); Great

Inagua, AMNH 21372 (5), 27193 (8); Little Inagua, AMNH

21297 (24), 21324 (6), 27663 (8). MISTERIOSA BANK: USNM

198599 (1). GRAND CAYMAN: FSM 10744 (25). JAMAICA:

LACM 6383 (1), 6384 (1), 6385 (4). PUERTO RICO: ANSP

118488 (1), LACM 6721-15 (1). ST. THOMAS: LACM 7789

(5). ANGUILLA: ANSP 114362 (1). ST. BARTHELEMY:

ANSP 127052 (2), 127057 (4), 127131 (12), 127574 (1), 127595

(1). ANTIGUA: ANSP 127597 (22). DOMINICA: USNM

198281 (6), 198282 (9), 201022 (1), 205074 (1), 212023 (1).

MARTINIQUE: ANSP 112972 (2), 113003 (2). ST. LUCIA:

ANSP 127057 (2), 127095 (1), 127116 (9), 127130 (27).

BEQUIA: ANSP 124601 (1), 126958 (1). LITTLE ST. VINCENT: ANSP 114329 (1), 127092 (1), 127098 (1). GRENADA:

ANSP 113241 (5), 114381 (3), 124599 (5), 127053 (1), 127129

(8). TOBAGO: ANSP 102189 (6), 102191 (10), 102193 (1),

102196 (3), 102197 (1), 102199 (2). TRINIDAD: USNM 198134

(22), 199159 (4). VENEZUELA: Charagato (Cubagua), USNM

212241 (6), 212242 (2), 212244 (8); Laguna Grande, USNM

212243 (2). COLOMBIA: Santa Marta, USNM 212108 (1).

PANAMA: vicinity of Colon, GCRL V69:3153 (1), V69:3486

(1), V69:S488 (1), V72:9183 (6), V72:9795 (1), V72:9866 (1); San

Bias Islands, GCRL V73:11O73 (1), V73:11152 (2). ALBUQUERQUE CAY: UMML 23327 (1). COURTOWN CAY:

UMML 23364 (13), 24023 (1). BELIZE (British Honduras):

FMNH 78689 (1), 78690 (10), 78691 (1), 78692 (1), 78693 (15),

78694 (16), UMML 9472 (3), 9543 (2), 9824 (9), 10314 (2).

YUCATAN: Banco Chinchorro, UMML 9368 (1), 9754 (1),

9770 (1). FERNANDO DE NORONJA: USNM 212024

(77). BRAZIL: Bahia, GCRL 1576 (17), 1579 (2).

While this study was in press, additional specimens representing northern range extensions of

M. triangulatus came to our attention: Florida Department of Natural Resources Marine Laboratory

4304 (2) and 4305 (16), St. Lucie Inlet, Martin

County, Florida. We were also informed of specimens from Indian River County, Florida, at FSM.

Literature Cited

Barlow, G. W.

1961. Causes and Significance of Morphological Variation

in Fishes. Systematic Zoology, 10(3): 105-117.

Ford, R. F.

1959. A Study of the Major Classification of Blennioid

Fishes Based upon Cranial Nerve Evidence. 51 pages.

MA Thesis, Stanford University.

Springer, V. G.

1958. Systcmatics and Zoogeography of the Clinid Fishes

of the Subtribe Labrisomini. Publications of the

Institute of Marine Science, University of Texas,

5:417-492.

Sverdrup, H. U., M. W. Johnson, and R. H. Fleming

1942. The Oceans, x + 1087 pages, 7 charts. Prentice-Hall,

Inc.

a us.



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