NOAA Technical Report NMFS 34 November 1985

Additions to a Revision of

the Shark Genus Carcharhinus:

Synonymy of Aprionodon and

Hypoprion, and Description

of a New Species of

Carcharhinus (Carcharhinidae)

J. A. F. Garrick

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service
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.'
NOAA Technical Report NMFS 34

Additions to a Revision of

the Shark Genus Carcharhinus:

Synonymy of Aprionodon and

Hypoprion, .and Description

of a New Species of

Carcharhinus (Carcharhinidae)

J. A. F. Garrick

November 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 proprietary product or proprietary material mentioned in this publication. No reference shall be made to NMFS, or to this

publication furnished by NMFS, in any advertising or sales promotion

which would indicate or imply that NMFS approves, recommends or

endorses any proprietary product or proprietary material mentioned herein,

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

advertised product to be used or purchased because of this NMFS

publication.
CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1

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

Results and conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2

Species accounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8

Carcharhinus isodon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8

Carcharhinus leiodon n.sp. 11

Carcharhinus hemiodon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13

Carcharhinus mac/oti . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 17

Carcharhinus signatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 20

Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 24

Literature cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 25

Figures

1. Proportional dimensions of the species expressed as ranges and means. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3

2. Proportional dimensions of the species expressed as ranges and means. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4

3. Proportional dimensions of the species expressed as ranges and means. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5

4. Proportional dimensions, vertebral numbers, and tooth numbers of the species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6

5. Carcharhinus isodon female from Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9

6. Carcharhinus isodon female from Florida, teeth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9

7. Carcharhinus leiodon n.sp. male from Gulf of Aden 12

8. Carcharhinus leiodon n.sp. male from Gulf of Aden, teeth 12

9. Carcharhinus hemiodon male from India. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14

10. Carcharhinus hemiodon male from India, teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14

11. Carcharhinus mac/oti . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18

12. Carcharhinus mac/oti, teeth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18

13. Carcharhinus signatus female from Northwest Atlantic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 21

14. Carcharhinus signatus male from Bahamas, teeth 21

Tables

1. Carcharhinus isodon and C. leiodon n.sp., proportional dimensions in percent of total length. . . . . . . . . . . . . . . . . . . . . . . . .. 10

2. Carcharhinus hemiodon, proportional dimensions in percent of total length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15

3. Carcharhinus mac/oti, proportional dimensions in percent of total length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19

4. Carcharhinus signatus, proportional dimensions in percent of total length 22

iii

Additions to a Revision of the Shark Genus

Carcharhinus: Synonymy of Aprionodon and Hypoprion,

and Description of a New Species of

Carcharhinus (Carcharhinidae)

1. A. F. GARRICKI

ABSTRACT

Features of the valid nominal species of Aprionodon Gill (isodon Valenciennes) and Hypoprion Miiller and

Henle (hemiodon Valenciennes, mac/oli Miiller and Henle, and signoJus Poey), plus those of a previously unrecognized

species here described as Carcharhinus /eiodon n.sp., are examined and compared with those of Carcharhinus

Blainville. Features studied include morphometries, vertebral numbers and other vertebral characteristics, tooth

numbers, color pattern, and some other aspects of external morphology. It is concluded that on these features

C. /eiodon n.sp. is entirely encompassed within the parameters of Carcharhinus, and that, although A. isodon,

H. hemiodon, H. mac/oli, and H. signoJus each extend the range of diversity of Carcharhinus in one or more features,

A. isodon is not uniquely different from Carcharhinus, and there is no common pattern of difference between

the three species of Hypoprion and Carcharhinus. Accordingly, and because the nature of the teeth of Aprionodon

and Hypoprion has been found insufficient to warrant generic distinction from Carcharhinus, the genera Aprionodon

and Hypoprion are synonymised with Carcharhinus.

A diagnosis and description are given for each of the above species. The descriptions include measurements,

counts, and line illustrations that show the whole shark in lateral view, underside of head, nostril, and teeth.

The geographic distribution is summarized, as are also the meager biological data available on number of embryos, size at birth, size at sexual maturity, and maximum size.

INTRODUCTION

At the time of completion of a revision (Garrick 1982) of Carcharhinus I accepted the validity of the genera Aprionodon and

Hypoprion. However, my subsequent study of these last two genera

now convinces me that they should be incorporated as junior

synonyms of Carcharhinus. Therefore a major purpose of the present account is to provide detailed information on features of the

species that were assigned to Aprionodon and Hypoprion, to allow

comparison with Carcharhinus, and to provide a basis for the

synonymy of these genera. A second purpose is to describe and illustrate each of these species, plus a new species of Carcharhinus,

and to document and collate information on their distribution and

some aspects of their biology. These latter aims are necessary

because, in general, the nominal species of Aprionodon and

Hypoprion are rather poorly known.

The history of Aprionodon Gill, 1861 and Hypoprion Muller and

Henle, 1841 (including Hypoprionodon Gill, 1862 as a synonym)

is covered fully in Compagno (1979), who detailed the nominal

species that have been referred to these genera and concluded that

Aprionodon is represented by only one valid species (isodon Valenciennes in Muller and Henle, 1841) and Hypoprion by three

(hemiodon Valenciennes in Muller and Henle, 1841; mac/oti Miiller

and Henle, 1841; and signatus Poey, 1868). Compagno (1979) further concluded from his studies that both Aprionodon and Hypoprion

should be synonymised with Carcharhinus Blainville, 1816, an action that he had earlier taken (1973, 1978) with respect to Aprionodon

but without substantiating it.

'Department of Zoology, Victoria University of Wellington, Private Bag,

Wellington, New Zealand.

As noted by Compagno (1979), the only reasons that have been

advanced for separating A. isodon from Carcharhinus are that it

is distinctive in having smooth-edged (upper) teeth and extremely

long gill openings. However, he found these reasons insufficient

because juveniles of one species of Carcharhinus (brevipinna) have

smooth-edged upper teeth while, conversely, an adult female A.

isodon has weak serrations on the bases of the upper teeth, and three

species of Carcharhinus (limbatus, amblyrhynchoides, and brevipinna) not only have gill opening sizes approaching those of A. isodon

but also agree closely with isodon in dentition, external morphology,

and vertebral counts.

Compagno's (1979) review ofthe diagnostic features of Hypoprion

led him to the view that the similarity between the three included

species in having upper teeth with enlarged basal serrae and essentially or completely smooth-edged cusps is not indicative of close

relationship nor clearly distinctive from Carcharhinus, and that

overall "Hypoprion is a heterogeneous assemblage with different

members closest to different species of Carcharhinus." Compagno

found the upper teeth of H. mac/oti unique in being low-based and

in having the large serrae restricted to the bases (thus the cusps are

completely smooth-edged), whereas in H. hemiodon and H. signatus

the upper teeth are high-based and in some specimens have irregular

serrations continuing on to the medial edges of the cusps (thereby

approximating the condition in Carcharhinus). He further noted that

several species of Carcharhinus have upper teeth similar to those

of hemiodon and signatus.

Other features evaluated by Compagno and found insufficient as

generic indicators for Hypoprion were nipple-shaped anterior nasal

lobes, a long first dorsal rear tip, a low and long second dorsal fin,

and a long snout. He concluded that the only one of these features
common to all three species was nipple-shaped nasal lobes, but that

these, as well as the fin and snout features, also have counterparts

in Carcharhinus species.

Although the above findings did not suppon recognition of

Hypoprion in its accustomed sense, Compagno noted that H. macloti

had cranial differences (hypercalcified rostrum and presence of an

epiphysial foramen) from H. hemiodon, H. signatus, and those Carcharhinus species that he had been able to examine. These differences, together with its unique teeth, could favor retention of

Hypoprion for H. macloti alone, but Compagno deemed this inadvisable because of the "absence of cranial material for several Carcharhinus species and the close similarity that H. macloti has with

Carcharhinus, especially C. sorrah . ..."

In the present study, based on a wider range of material than was

available to Compagno (1979), the morphometrics, vertebral numbers

and other vertebral characteristics, tooth numbers, color pattern,

and some other aspects of the external morphology of the species

of Aprionodon and Hypoprion are compared with those of Carcharhinus as a whole. Included in the comparison are data from

an undescribed species, so far known from only one specimen, which

has smooth-edged upper teeth conforming to the generic diagnosis

of Aprionodon. Following the generic comparison in which the conclusion is reached that Aprionodon and Hypoprion are synonyms

of Carcharhinus, a detailed account of each of the nominal species

ofAprionodon and Hypoprion is given, and the undescribed species

is described as C. leiodon n.sp.

MATERIALS AND METHODS

Specimens examined by me and identified as Aprionodon and Hypoprion in this study came from the museums listed below. Abbreviations

preceding the names of each of these museums are those Llsed in the text.

BMNH British Museum (Natural History), L'iTIdon

IRSN Institut Royai des Sciences Naturelles de Belgique. Brussels

ISZZ Institut fur Spezielle Zoologie und Zoologisches Museum, Berlin

MNHN Museum National d'Histoire Naturelle, Paris

MRAC Musee Royal de I'Afrique Centrale, Tervuren, Belgium

NMV Naturhistorisches Museum, Vienna

RNH Rijksmuseum van Natuurlijke Historie, Leiden

SU Division of Systematic Biology, Stanford University (this collection has since

been transferred to the California Academy of Sciences, San Francisco)

UMMZ University of Michigan Museum of Zoology, AIm Arbor

USNM United States National Museum of Natural History, Washington, D.C.

Data on Carcharhinus used there for comparison with Aprionodon and Hypoprion in Figures 1-4 are the combined ranges ofthe 25 species

recognized by Garrick (1982) and presented in his figures 2-8, 10, II and tables I, 2, and 4.

The methods used for taking measurements from which proportional dimensions were calculated, and for making counts of teeth and

vertebrae, were the same as those described in Garrick (1982).

RESULTS AND CONCLUSIONS

Figures 1-4 present comparative data on proportional dimensions,

vertebral numbers, and tooth numbers in Aprionodon, Hypoprion,

and Carcharhinus. The data for each species of Aprionodon and

Hypoprion and for C. leiodon n.sp. are presented separately, whereas

those shown for Carcharhinus are the combined ranges of the 25

species recognized in Garrick (1982). The ranges and means of the

data for each species ofAprionodon and Hypoprioll are based principally on the small samples of specimens examined in the present

study, and for the most part the values for individual specimens are

shown in Tables 1-4 and the accompanying species descriptions. For

C. leiodon n.sp. only one specimen was available; for the other

species the numbers of specimens from which the majority of the

data was taken were as follows: A. isodon, 6; H. hemiodon, 5; H.

macloti, 7; and H. signatus, 5.

The items selected for inclusion in Figures 1-4 are the same as

those used by Garrick (1982) in his study of Carcharhinus, and were

chosen for the same three reasons, i.e., they are features which have

commonly been used in the past to distinguish carcharhinid taxa,

or they have been found to have value for that purpose in the pressent study, or they contribute to a broad picture of morphometrics

and meristics of these taxa.

Data for Aprionodon isodon are almost entirely encompassed

within the ranges of the data for Carcharhinus in Figures 1-4 where

31 characters are treated. The exceptional data (Fig. 2c) are those

for gill opening lengths, in which the values for A. isodon exceed

2

the ranges of values for Carcharhinus species. Taking the first gill

opening length as an example, since it is the most obviously different fwm Carcharhinus, its mean length in A. isodon (4.9% TL)

is clearly greater than in any Carcharhinus species, among which

the highest means occur in amblyrhynchoides (4.0%) and limbatus

(3.9 %). However, four Carcharhinus species (amblyrhynchoides,

limbatus, brevipinna, and leucas) have first gill opening length ranges

overlapping the A. isodon range, thus establishing that A. isodon

is not uniquely different from Carcharhinus in that feature.

Although A. isodon shares with C. leiodon n.sp. the unusual

feature of having essentially smooth-edged upper teeth, the generally

low degree of congruence between the data for A. isodon and C.

leiodon n.sp. in Figures 1-4 offers little support for the possibility

that these species are more closely related to each other than to other

species of Carcharhinus. The same conclusion can be reached for

most other characters examined in the present study but not shown

in Figures 1-4; for example, color pattern and the position where

diplospondyly begins. In C. leiodon n.sp. the fins are prominently

black-tipped and diplospondyly begins above the anterior part of

the pelvic base, whereas in A. isodon the fins lack black tips and

diplospondyly begins much further posteriorly, above or behind the

pelvic axil.

Based on the above findings, A. isodon and C. leiodon n.sp. are

sharks of predominantly "average" Carcharhinus morphology,

smooth-backed, and with pointed snouts. These characters, even in
PRENARIAL LENGTH AS PERCENT TOTAL LENGTH

I I CARCHARH I NUS

H. HEMIODON I I I H. MAC LOT I

t--+----< H. SIGNATUS

I I I A. ISODON I C. LEIODON N.SP. a I , 3 4 5 6

PREORAL LENGTH AS PERCENT TOTAL LENGTH

I I CARCHARH I NUS

I I I H. HEMIODON

I I I H. MACLOTI H. S I GNATUS I I I

I I I A. lSODON

b I C. LEIODON N.SP.

4 5 6 7 6 9 10 11

SNOUT TIP TO PECTORAL ORIGIN

AS PERCENT TOTAL LENGTH

I I CARCHARH INUS

..........-..-. H• HEMIODON I------+--i H. MACLOTI H. S IGNATUS

I I I A. ISODON I C. LEIODON N,SP. C . 16 20 22 '4 26

SNOUT TIP TO PELVIC ORIGIN

AS PERCENT TOTAL LENGTH

I I CARCHARH INUS

............... H• HEMIODON

I I I H. MACLOTI

I I I H. SIGNATUS

I I I A. ISODON

d I C. LEIODON N.SP.

44 46 46 50 5> 54 56

SNOUT TIP TO FIRST DORSAL OR IGIN

AS PERCENT TOTAL LENGTH

I I CARCH"'RH I NUS

I-H H. HEMIODON

I--+---t H. MACLOTI

I I I H. SIGN...TUS

......-+--I "'1 ISODON

I C, LEIODON N,SP.

e I

26 '6 30 32 34 36

SNOUT TI P TO SECOND DORS"'L OR IGIN

"'S PERCENT TOT"'L LENGTH

I I C"'RCH"'RH I NUS

t--+--i H. HEMIODON

I I I H. MAC LOTI

I I I H. SIGN",TUS

I I I .... ISODON

f I C. LEIODON N,SP,

56 56 60 62 64 66 66

EYE DIAMETER AS PERCENT TOTAL LENGTH

I I C"'RCH"'RH I NUS

.............. H, HEMlODON I I I H. MAC LOTI

I I I H. S IGNATUS

I I I .... ISODON

g I C, LEIODON N,SP.

()OS 10() 1-5 2-0 205 J.O 3-5

MOUTH WIDTH "'S PERCENT TOT"'L LENGTH

I I C"'RCHARH INUS

I I I H. HEMIODON

I I I H. MACLOTI

t--t--I H. S IGN...TUS

I I I .... ISODON

h I C. LEIODON N.SP. . 6 7 6 9 10 II 12

FIgure 1.-Propor1IooaJ dimensions ofthe species fonnerly referred to Hypoprion (H. hentiodon, H. macloG, and H. signatus)

and Aprionodon (A. isodonl, and those of Carcluuhinus leiodon n.sp. expressed as ranges and means. For each dimension

the range in 2S species of Carcharhinus is also shown for comparison.

3
LABIAL FURROW LENGTHS AS PERCENT TOTAL LENGTH

I I I I CARCHARH I NUS

'"---+--l H• HEMIODON UPPER .....-+----i LOWER I I I H. MACLOTI t--+---l H. SIGNATUS

I--+i H---t A. ISODON I

a I C. LEIODON N.SP • 0·2 Do< a.; 008 c·:? . ._--_. 0" 0-6 o·a

PECTORAL ANTERIOR MARGIN

AS PERCENT TOTAL LENGTH

I , CARCHARH I NUS

I I I H. HEM IODON I I I H. MACLOTI I I I H. S I GNATUS

A. ISODON

b I C. LEIODON N.SP. 12

" 16 la 20 22 2. 26 2a

GILL OPENING LENGTHS AS PERCENT TOTAL LENGTH

I I I I I I CARCHARH INUS

FIRST .... >+l .... H. HEMIODON 1---+4 THIRD ......... FIFTH ...... H. MAC LOT I I-+< ... H. S I GNA~US

f--I--4 A. I SODON

C I I I C. LEIODON N.SP. , 2 3 . 6 . . . . 5 2 3 • 5 G 7 1 2 3 • 5 6

FIRST DORSAL HE I GHT

AS PERCENT TOTAL LENGTH

I I ':ARCHARH INUS

--- H. HEMIODON

H. MAC LOTI t--+--l H. S IGNATUS

, I I A. 1SODON

d I C. LEIODON N.SP.

6 a 10 ,2 14 16

FIRST DORSAL REAR TIP AS PERCENT TOTAL LENGTH

I I CARCHARH I NUS

1-+-4 H. HEMIODON I I I H. MACLOTI

J---+--ol H• S IGNATUS

............... A. I SODON I C. LEIODON N.SP. e 2 3 • 5 6 ; a

SECOND DORSAL HE I GHT

AS PERCENT TOTAL LENGTH

I I CARCHARH INUS

H. HEMIODON

H. MACLO~ I

t-H H. S IGNATUS

A. I SODON

f c. LEICDON N.SP.

1 2 •3 •_. 5

UPPER CAUDAL LENGTH

AS PERCENT TOTAL LENGTH

I I CARCHARH 1NUS

t--+--< H. HEMIODON ......-...... H• MACLOTI

I I I H. S IGNATUS

.......)--4 A. ISODON

g I C. LEIODON N.SP.

22 2. 26 2& 30 32

PREORAL LENGTH

PRENARIAL LENGTH

I I CARCHARHINUS

I I I H. HEMIODON

I I I H. MACLOTI

............... H• S IGNATUS

I I I A. :SODON

h I C. LE IODON N. SP.

1~~ ---'

2-C 2·2 2-4 2'6 2a 3{) 3-2

Figure 2.-Proportional dimensions of the species formert)' referred to Hypoprion (H. hemiodon, H. modoti, and H. signatus)

and Aprionodon (A. isodon), and those of Carcharhinrls leiodon n.sp. expressed as ranges and means. For each dimension

the range in 25 species of Carcharhinus is also shown far comparison.

4
PREORAL LENGTH

I NTERNAR lAL DISTANCE

I I CARCHARH I NUS

I---+-< H, HEMIODON H, MAC LOTI

I I I H. SIGNATUS

.......-.+---i A, I SODON

I C, LEIODON N,SP.

a . . <Hi 0·8 '-0 '-2 ,-, \·6 '-8 2·0

FIRST DORSAL HEIGHT

FIRST DORSAL REAR TIP

I I CARCHARH I NUS

I-------t--4 H. HEMIODON

t-+-l H. MACLOTI

I I I H. SIGNATUS

I I I A, I SODON

b I C, LElODON N, SP.

"2 \-6 2{) 2-. 2-8 3-2 3-6

FIRST DORSAL BASE

FIRST DORSAL REAR TIP

I I CARCHARH INUS

>-+-t H, HEMIODON

t---+---4 H. MACLOTI H. S IGNATUS

I I I A, ISODON

I C, LEIODON N.SP,

C '·2 '-6 2-0 H 2'" 3-2 3" H) .-. FIRST DORSAL HEIGHT

SECOND DORSAL HE I GHT

I I CARCHARH I NUS

I I I H. HEMIODON

I I I H, MACLOTI

I I I H. SIGNATUS

I I I A, I SODON

d I C, LEIODON N.SP.

'-5 2-0 2-5 3.Q 3-5 ..0 '-5 5.Q 5·5 6.()

SECOND DORSAL REAR TIP

SECOND DORSAL HEIGHT

I I CARCHARH I NUS

I , I H. HEMIODON H, MACLOTI

I I I H, SIGNATUS

f--+-i A, ISODON

I C. LEIODON N.SP. e 20b 2:2 . 0-6 <>8 '-0 ',2 ,-, ,.. '-8 ... 2.. 2-8 3-0

SECOND DORSAL HEIGHT

ANAL FIN HEIGHT

I I CARCHARH I NUS

............... H, HEMIODON

I I I H, MACLOTI

I I I H, S IGNATUS

I I I A, I SODON

f I C. LEIODON N.SP,

C>5 <>6 0-7 <Hi <>g .0 ,.\ \'2

PECTORAL ANTERiOR MARGIN

PECTORAL WIDTH

I I CARCHARH I NUS

I I I H. HEMIODON

I I I H, MACLOTI

I I I H, S I GNATUS

t--t-I A, ISODON

g I C. LEIODON N.SP,

,.. "5 ,-<; \-7 \-8 ,-g 2-0 2-' 2~2 2-3

Figure 3.-Proportlonal dimensions oI'the species fonnerly referred to Hypoprion (H_ hemiodon, H. I1UU:loti, and H. signatus)

and Aprionodon (A_ isodon), and those of Carcharhinus leiodon n.sp. expressed as ranges and means. For each dimension

the range in 25 species of Carcharhinus is also shown for comparison.

5
UPPER CAUDAL LENGTH

LOWER CAUDAL LENGTH

I I CARCHARH INUS

.......-+-t H, HEMIODON I I I H. MAC LOTI

I I I H. S IGNATUS

I I t A. ISODON

a I C, LEIODON N,SP.

"6 ',8 2-0 2·2 2·' 2·8 2·8 3-0

DISTANCE BETWEEN SECOND DORSAL AND ANAL FIN

ORIGINS AS PERCENT TOTAL LENGTH ANTERIOR (- VEl

OR POSTERIOR (+ VEl TO ANAL FIN ORIGIN

I I CARCHARH I NUS

.......-+-t H, HEMIODON

I I I H, MACLOTI

I I I H. S IGNATUS

I I I A. ISODON

b I C. LEIODON N.SP,

-ve- 3 2 , 0 I 2 3 .. +ve

LENGTH

DIAMETER OF PENULTIMATE MONOSPONDYLOUS CENTRUM

I I CARCHARH I NUS

t-+-1 H, HEMIODON

I I I H, MAC LOTI

t-+-t H, SIGNATUS

t--+-i A, ISODON

I C, LEIODON N.SP. C D·. 0'6 0'8 1·0 ',2 ,.. 1·6 1·8 2·0 2-2

LENGTH OF PENULTIMATE MONOSPONDYLOUS CENTRUM

LENGTH OF FIRST DI PLOSPONDYLOUS CENTRUM

I I CARCHARH I NUS

............... H• HEMIODON H. MACLOTI

I-H H, S IGNArUS

I I I A. ISODON

d I C. LEIODON N.SP. . . . 1·0 I,' 1'8 2-2 2-8 3·0 3"

TOTAL VERTEBRAL NUMBERS

I I CARCHARH I NUS

H. HEMIODON

.... H• MACLOT I

t-+-I H, S IGNATUS

..... A• ISODON

I C. LEIODON N.SP.

e 100 '20 !40 160 ,80 200 220 2.0

PRECAUDAL VERTEBRAL NUMBERS

I I CARCHARH I NUS

.. H• HEMIODON

.. H, MACLOTI

...... H• S IGNATUS

.. A, ISODON

f I C, LEIODON N.SP. . '0 60 80 '00 '20 "0

CAUDAL VERTEBRAL NUMBERS

I CARCHARH I NUS I

....... H• HEMIODON

.... H• MACLOTI

1-+4 H. S IGNATUS

II A. ISODON

I C. LEIODON N. SP,

g . ,20 '0 60 80 '00

TOOTH NUMBERS

I I CARCHARHINUS I I

12 2 8 2 H, HE~\I0DON

11 3 8 6 H, MACLOTI

2 6 H, SIGNATUS UPPER LATERALS 9 1 LOWER LATERALS

8 A· ISODON 8 2 C, LEIODON N,SP,

h 2

;0 1: 1<:: 13 ,. 15 16 17 " 12 13 ,. '5 16 ,7 18

Figure 4.-Proportional dimensions, vertebral numbers, and tooth numbers ofthe species formerly referred to HYJXJprion

(H. hemiodon, H. mac/oti, and H. signatus) and of Aprionodon (.1. isodon), and those of Carcharhinus leiodon n.sp. In

a-g, data are expressed as ranges and means. In h, tooth numbers are given as a frequency table. For a-h, the range

in 25 species of Carcharhinus is also shown for comparison.

6
combination, are shared by several Carcharhinus species and hence

offer no grounds for aligning A. isodon and C. leiodon n.sp. in a

genus separable from Carcharhinus. Therefore the only remaining

feature that might be used to support such action is the nature of

the teeth, but as already demonstrated by Compagno (1979) these

are insufficiently distinctive for that purpose. Accordingly, A. isodon

is here treated as a species of Carcharhinus, in line with Compagno's

(1979) findings.

Decision on the status of Hypoprion versus Carcharhinus is

similarly, but less obviously, resolved. As can be seen from Figures

1-4, the three Hypoprion species have values for several characters

that variously exceed the ranges of Carcharhinus (including

Aprionodon). In particular, these characters include three simple

dimensions (prenariallength, preoral length, and first dorsal rear

tip as percent total length) and three ratios incorporating these and

other simple dimensions (preoral length/internarial distance, first

dorsal height/first dorsal rear tip, and first dorsal base/first dorsal

rear tip). Since there is a direct correlation between some of these

characters (e.g., between prenarial and preoral lengths, and between

the simple dimensions and the ratios incorporating them), attention is focused here on only two of them, i.e., preoral length as

percent total length and first dorsal rear tip as percent total length.

The mean values for preoral length in H. macloti (9.5 %) and H.

signatus (9.3 %) are slightly greater than in any Carcharhinus species,

in which the highest means occur in bomeensis and porosus (each

with 8.7%). However, eight Carcharhinus species have ranges overlapping the range for H. macloti and ten the range for H. signatus.

By contrast H. hemiodon, with a mean of 7.1 %, has a preoral length

like an "average" Carcharhinus, and there are 20 species of Carcharhinus with ranges that overlap its range.

The mean values for first dorsal rear tip in H. hemiodon (6.1 %)

and H. macloti (6.0%) are distinctly greater than in any Carcharhinus

species, in which the highest means are in borneensis (4.8%),

porosus (4.7%), and altimus (4.7%). Only one Carcharhinus species

(porosus) has a range overlapping the range for H. hemiodon, and

only four overlap that for H. macloti. In marked contrast, H. signatus

with a mean of 4.0% is "average" for Carcharhinus, and there are

22 species of Carcharhinus with ranges overlapping that for H.

signatus.

A third simple dimension, length of second dorsal rear tip as percent total length, although not included in Figures 1-4, also shows

a difference between H. macloti and all Carcharhinus and a similarity between H. macloti and H. hemiodon comparable with that provided by first dorsal rear tip. The mean value for H. macloti (4.5%)

is minimally greater than in any Carcharhinus species, where the

highest means are in bomeensis (4.4%) andfalcifonnis (4.3%). The

mean in H. hemiodon is 4.2%, and in H. signatus 3.8%. However,

14 Carcharhinus species have ranges overlapping the range for H.

macloti, and 21 and 25 species have ranges overlapping those for

H. hemiodon and H. signatus, respectively.

It is clear from the above analysis that the data in Figures 1-4 offer no basis for recognizing Hypoprion as distinct from Carcharhinus. On the one hand, the few differences that are apparent

are all mean differences, and on the other hand none of the differences is common to all three Hypoprion species. A long preoral

length is shared by H. macloti and H. signatus but not by H.

hemiodon. A long first dorsal rear tip, and less trenchantly a long

second dorsal rear tip, are common to H. macloti and H. hemiodon

but not to H. signatus. Based on these data, H. macloti is the most

distinctive of the three species relative to Carcharhinus.

Other characters examined, but not shown in Figures 1-4, yield

findings parallel to the above. With respect to color, hemiodon has

7

black-tipped fins but not so signatus and macloti, though the lastnamed is distinctive in having white trailing edges on the paired

fins, the anal fin, and the lower lobe of the caudal fin. Both signatus

and macloti have diplospondyly beginning above the pelvic base,

whereas in hemiodon it is further posterior, from the level of the

pelvic axil to between the pelvic tip and anal fin origin. An interdorsal ridge is common to signatus and to some, but perhaps not

all, specimens of macloti and hemiodon. A discrete series of enlarged

hyomandibular pores is present in macloti but not in signatus or

hemiodon; it may be meaningful that the only Carcharhinus species

with comparable pores is bomeensis which agrees further with

macloti in having a long preoral length; long first and second dorsal rear tips; the second dorsal origin over the middle of the anal

fin base; white trailing margins on the pectoral, pelvic, and anal

fms; very large basal serrae on the lateral margins ofthe upper teeth;

and a nipple-shaped anterior nasal lobe. All three species of

Hypoprion have similar anterior nasal lobes, but so do several species

of Carcharhinus.

The overall conclusion that must be reached from the present study

is that although hemiodon, macloti, and signatus each extend the

range of diversity of Carcharhinus in one or more features, there

is no common pattern of difference from Carcharhinus other than

in the nature of the upper teeth-and even this dental difference is

not consistent, as indicated by Compagno (1979). Were this difference

in the upper teeth matched by even one other common but singular

distinction from Carcharhinus, the case for retaining Hypoprion as

a separate genus could be readily made. Since this is not so, the

distinction based on the teeth alone, Le., on the presence of large

basal serrae coupled with essentially smooth-edged margins distally, must also come under more stringent scrutiny. Several Carcharhinus species (including bomeensis, cautus, dussumieri,

porosus, and sealei, amongst others) have comparably large basal

serrae, and one (brevipinna) has smooth-edged margins at least in

juveniles, thus supporting Compagno's (1979) conclusion that

Hypoprion should by synonymised with Carcharhinus. I agree with

Compagno's conclusion. It is also evident that the present data further support Compagno's findings that macloti is the most divergent

of the three nominal species of Hypoprion. These data, even when

combined with the cranial and dental peculiarities of macloti noted

by Compagno, seem insufficient to warrant retaining Hypoprion as

a separate genus for macloti alone, because of the various features

shared by macloti and either hemiodon or signatus, and macloti and

various species of Carcharhinus.
SPECIES ACCOUNTS

Carcharhinus isodon (Valenciennes in

Miiller and Henle, 1841)

Figures 5, 6, Table 1

Carcharias (Aprion) isodon Valenciennes in Muller and Henle,

1841:32-33. One spirit specimen in the Paris Museum from

Milbert; no locality mentioned in original description, but Paris

Museum data give it as New York.

DlAGNOSIS.-Moderately large sharks. up to 1.55 m long. lacking an interdorsal ridge; fin tips without dark markings though the

leading margins of the dorsals and both margins of the upper caudal

may be narrowly dark-edged; snout moderately long and sharply

pointed; internarial width 1.2 to 1.4 in preoral length; origin of first

dorsal fin over or just behind middle of inner pectoral margin; apex

of first dorsal sharply rounded to pointed; origin of second dorsal

from slightly in front of to dightly behind anal fin origin; height

of second dorsal 2.5-2.9% TL and 1.4-1.6 in length of its rear tip;

dental formula usuaily 15-2-15/14-3-14; upper teeth narrow, erect to

slightly oblique, concave laterally and medially, and smooth-edged;

lower teeth erect, smooth-edged; no obvious discrete series of enlarged hyomandibular pores alongside corner of mouth; precaudal

centra 78-80; cauda] centra 85-87; total centra 163-167; diplospondyly begins from pelvic axil to behind pelvic tip; anterior diplospondylous centra alternate slightly but regularly in length; penultimate

monospondylous centrum 1.0-1.1 times longer than wide.

The species most likely to be confused with isodon are amblyrhynchoides, brevipinna, limbatus, and C. leiodon n.sp. which have in

common with it all or most of the following features: narrow and

essentially erect upper teeth, no interdorsal ridge, a pointed and

moderately long snout, large gill openings, and long labial furrows.

It differs from all of these species in lacking black fin tips; from

amblyrhynchoides, brevipinna, and limbatus in having the first dorsal

origin over the middle of the pectoral inner margin (over the pectoral axil in amblyrhynchoides and limbatus, and over or behind

the pectoral inner corner in brevipinna) and in details of the teeth;

and from C. leiodon n.sp. in having a much lower second dorsal fin.

NOMENCLAIURAL DISCUSSION.-The holotype ofisodon Valenciennes in Muller and Henle (1841) is in good condition and agrees

well with the original description where isodon, although not illustrated, was compared with brevipinna Muller and Henle and

placed with that species, and also acutidens Ruppell (= Negaprion

acutidens), in the new subgenus Aprion Muller and Henle. Gill

(1862), who recognized that Aprion was preoccupied (see Bigelow

and Schroeder 1948), proposed the replacement name Aprionodon

with punctatus as type-species, an action based on his belief that

Squalus punctatus Mitchill, 1815 was a senior synonym of isodon

(see Gill 1864). However, as evident from Mitchill's description of

punctatus in Gill (1864), where the upper lobe of the caudal fin is

said to be "almost thrice as large as the lower" these two species

cannot be synonymous. There are no other primary synonyms of

isodon. Springer's (1950) suggestion "that there are two American

forms of Aprionodon and that the Texas and north Gulf of Mexico

population may represent an undescribed species" has not been further substantiated.

DESCRIPTION (see also Table 1).-Moderately large sharks, growing to at least 1.55 m TL. Midline of back between dorsal fins

smooth, lacking an interdorsal ridge. Upper precaudal pit strongly

8

developed, lower pit weak.

Dermal denticles in small specimens close-packed and overlapping, subcircular in outline, each with three longitudinal ridges

and corresponding posterior marginal teeth, the latter sharp-pointed

but rather short.

Snout of moderate length and sharply pointed in contour. Anterior

margin of eye above front of mouth. Nostrils strongly oblique,

slitlike, the anterior margin of each with a low, pointed lobe.

Dental formula 15-2-15/14-3-14 in five specimens counted. Upper

teeth narrow, erect near the center of the mouth but slightly oblique

laterally, medial and lateral margins concave, both margins essentially smooth-edged, although there are slight irregularities basally, particularly on the lateral margins; two small symphysial teeth.

Lower teeth narrow, erect, with both margins deeply concave, and

smooth-edged; three small symphysial teeth.

First dorsal fin moderately low, erect rather than falcate, its apex

sharply rounded to pointed; origin of first dorsal over or slightly

behind middle of posterior (inner) pectoral margin. Second dorsal

fin moderately low and long, almost equal to anal fin; length of second dorsal rear tip 1.4 to 1.6 (mean 1.5 in six specimens) times its

height; origin of second dorsal from slightly anterior to slightly

posterior to anal fin origin. Pectoral fin short, slightly falcate, and

pointed distally; origin of pectoral fin below or only just anterior

to fifth gill opening; outer corner of pectoral, when fin is adpressed

to trunk so that its anterior margin is horizontal, reaches almost

or quite to first dorsal axil.

After preservation in alcohol, the color of the back and sides is

grey to dark grey while the underside is pale, and a tongue of the

pale color may extend forward along the side from the pelvic region

to below the first dorsal fin. The leading margins of the two dorsal

fins and both margins of the upper caudal lobe are usually narrowly edged with a dusky color or black.

Vertebral counts as in Table 1. Centrum diameter greater than centrum length except in longest monospondylous centra at posterior

of abdomen where diameter and length are approximately equal.

Anterior diplospondylous centra alternate slightly but regularly in

length. Diplospondyly occurs from above the pelvic axil to behind

the pelvic tip. Length/diameter of penultimate monospondylous centrum is 0.98 to 1.12 (mean 1.04 in four specimens), and length of

penultimate monospondylous centrum/length of first diplospondylous centrum is 1.33 to 2J17 (mean 1.57 in four specimens).

Of the five specimens of isodon examined by me, four were

newborn or juveniles, 413-631 mm TL, and the fifth was a mature

female, about 1,500 mm. A similar disparity of sizes and a relative

paucity of adult records are evident from the literature. The few

records of adults include those of Springer (1950) who noted that

adults "appear in relatively large numbers in less than 10 fathoms

(18 m) off Salerno, Florida, during December and January" but not

in other months. He gave the lengths of 20 adult females as

1,473-1,549 mm and of 6 adult males as 1,397-1,524 mm. Dahlberg

and Heard (1969) listed only one presumably adult specimen, 1,445

mm long, in a collection of 30 specimens from off Georgia in July

to September. Branstetter and Shipp (1980) reported five adults, two

of them females 1,270-1,390 mm, and three males 1,120-1,270 mm,

taken off Alabama in June and July. Branstetter (1981) summarized

unpublished data from Moran (Im)2 on six females 1,230-1,420

mm from the northern Gulf of Florida. All othel records from the

'Moran, 1. L. 1972. The occurrence of sharks in two bays off the northern Gulf

coast of Florida. Unpub/. senior research project, 26 p. Florida State University,

Tallahassee.
(((((

a

b

Figure 5.-Carcharhinus isodon, USNM 118457, 496 mm TL, female from Texas: a, left side (redrawn and modified from Bigelow and Schroeder 1948, fig. 51); b, underside

of head.

Figure 6.-Carcharhinus isodon, USNM 143761, ca. 1,500 mm TL, female from Florida; right upper and lower teeth (symphysis to the right); inset

teeth are enlarged fifth upper and lower teeth.

9
Table 1. Carcharhinus isodon and £. leiodon n.sp., proportional dimensions in percent of total length.

£.. leiodon n. sp..

• 413 mm .453 mm • 496 mm Texas Mississippi Texas USNM 130651 USNH 126118 USNH 118457

Snout tip to: outer nostrils 3.6 4.1 3.1

eye 7.0 7.6 7.1

mouth 7.0 7.6 7.3

1st gill-opening 21. 5 21. 8 19.4

3rd gill-opening 23.9 24.0 23.0

5th gill-opening 25.2 25.6 25.0

pectoral origin 24.7 25.4 24.6

pelvic origin 47.4 47.4 48.2

1st dorsal origin 32.0 32.2 32.1

2nd dorsal origin 61.0 60.1 62.5

anal fin origin 60.5 60.3 61. 5

upper caudal origin 73.1 72.0 74.2

lower caudal origin 72.1 71. 9 7). E

Nostrils: distance between inner corners 5.8 5.7 5.4

Mouth: width 8.5 8.2 Q .7

length 6.3 6.2 5.8

Labial furrow lengths: upper J.8 0.9 0.9

, lower 0.8 0.8 ~. 8

Gill-opening lengths: 1st 4.2 5.0 4.3

3rd 4.8 5.4 4.'.J

5th 4.0 4.4 •. 3

Eye: horizontal diameter 2.2 2.2 1.9

1st dorsal fin: length base 9.7 8.8 10.0

posterior margin 3.8 4.0 3.5

height 8.5 8.8 8.9

2nd dorsal fin: length base 4.1 4.1 4.3

posterior margin 4.1 4.0 3.7

height 2.8 2.5 2.5

Anal fin: length base 5.0 4.9 4.8

posterior margin 3.6 3.6 3.3

height 3.1 3.1 3.2

Pectoral fin: length base 5.8 5.3 5.6

anterior margin 16.0 15.4 14.7

distal margin 10.2 9.9 !('.l

greatest width 8.5 8.2 a.1

PelvI.c fin: length base 5.1 5.1 5.1

anter ior margin 5.7 5.5 5. :

dista 1 margin 4.8 5.4 5.1

length claspers

Caudal: length upper lobe 27.8 28.5 :n.6

length lower lobe 12.1 11. 9 11. )

Trunk at pectoral origin: width 10.4 H,.6 J 0.5

height JO.6 11. 0 11. 3

formula 15-2-J5 15-2-15 10-2-15 Dental 14-3-14 14·,)-:4 1 ~- )-14

Vertebrae: precaucJ.al 80 78 79

caudal 87 d5 85

total 167 163 164

d 510 mrn!.

Alabama

USAIC 6278

7.6

23.9

49.8

32.4

61.8

62.5

5.3

8.6

4.5

5.3

3.5

1.6

9.0

4.3

7.5

4.3

4.3

2.7

4.7

3.7

2.9

5.1

5.1

5.7

29.2

10.8

d 631 mm 2.

New York

HNHN 1037

3.6

6.8 ".8 19.6

22.5

24.7

24.4

46.7

31.5

60.5

60.2

72.4

71. 4

5.3

8.7

5.9

0.9

0.9

5.7

5.9

4.5

1.7

10.1

4.0

9.7

4.4

4.0

2.9

4.6

4.0

3.4

5.3

16.0

11. 4

8.2

5.!

5.8

5.1

2 •.t1

27.7

12.3

10.4

11.1

15-2-15

14-3-14

80

86

166

1390 nun!.

Alabama

USAIC 6278

6.5

22.7

53.2

33.1

64.7

63.3

5.0

9.4

5.8

6.5

5.4

1.3

10.1

4.0

10.6

4.7

4.0

2.9

5.3

3.5

3.1

5.8

4.7

6.3

28.1

12.6

d 750 nun

Gulf of Aden

NMV 61-465

3.2

6.7

6.7

19.8

22.5

25.3

24.9

50. ]

32.6

64.4

64.0

76.1

75.7

6.3

9.6

5.5

0.4

0.6

4.0

4.5

3.2

1.9

11. 2

4.4

10.5

5.1

3.5

4.1

5.6

3.3

4.4

6.5

17.4

14.5

10.8

6.3

6.7

7.1

2.8

24.8

13 .1

14.2

12.8

16-3-16

15-3-15

115

83

198

1. Data from Branatetter • Shipp (1980) on lIpecimena in the univeral.ty of South Alabama Ichthyoloqical Collect.ior;.

2. Holotype of Carcharia. (Aprion) i.odon.

10
western North Atlantic which I have seen are clearly of newborn

or juveniles. They include Baughman and Springer (1950-432 nun),

Bigelow and Schroeder (1948-460 to 567 nun), Radcliffe (1916-508

nun), Dahlberg and Heard (1969-520 to 940 nun), Muller and

Henle (1841)-631 nun, holotype of isodon), Bearden (1965-695

mm), Burton (1940-747 mm), Clark and von Schmidt (1965-760

mm), and Springer (1938-762 mm). For the western South Atlantic, Sadowsky (1967) recorded two males from southern Brazil of

1,101 and 1,148 nun which he described as half-grown. Springer's

works (1950, 1960) contribute to estimates of probable birth size

and litter number in isodon. Of 20 adult females from Salerno,

Florida, (Springer 1950) 13 had 1-6 embryos 432-483 nun long and

7 had recently pupped. His estimate of birth size (1960-from his

fig. 3) was about 435-610 nun. Branstetter and Shipp (1980) reported

four late embryos, 490-510 nun long, two in each uterus, from a

1,390 nun female taken off Alabama in June, and proposed birth

size of 450-550 nun. They estimated that males become mature at

lengths between 1,150 and 1,200 nun (based on their inunature male

of 1,120 mm and two mature males of 1,200 and 1,270 nun). For

females they proposed a larger size at maturity, noting that their

1,270 nun specimen was still inunature whereas their 1,390 nun

female was gravid. Branstetter (1981) supplemented these data with

information from Moran (footnote 2) on four inunature females

(1,230, 1,260, 1,370, and 1,420 mm) and two gravid females (1,370

and 1,420 mm) from the northern Gulf coast of Florida, and concluded that females become mature at lengths near 1,400 nun. The

maximum size so far reported for isodon is 1,524 nun for males

and 1,549 nun for females (Springer 1950).

Although Springer (1950) suggested that "comparison of new-born

summer young from the coast of Texas with winter late embryos

from Salerno indicates that there are two American forms of

Aprionodon and that the Texas and north Gulf of Mexico population may represent an undescribed species" he did not give further

information on this phenomenon.

DISTRIBUTION (see also Material Examined).-Western Atlantic

from New York to southern Brazil but generally not well

documented. The few specimens I have seen have been from New

York (holotype of isodon), the east coast of Florida (Salerno), and

the northern Gulf of Mexico (Texas and Mississippi). Specimens

from these latter regions (Florida and the northern Gulf of Mexico) have also been the subject of the most extensive or detailed accounts of isodon in the literature, including particularly those of

Bigelow and Schroeder (1948-Mississippi and Texas) and Springer

(1950-both coasts of Florida and Mississippi). Supplementary accounts for the same regions are by Springer (1938-Florida),

Baughman and Springer (1950-Texas), Clark and von Schmidt

(1965-Florida), Applegate et al. (1979-who include an illustration

of isodon in their account of Mexican sharks but do not give a detailed locality or record for the Gulf of Mexico), Branstetter and Shipp

(1980-Alabama), and Branstetter (1981-Alabama and Florida).

Northward of these regions there are scattered records or listings

from Georgia (Dahlberg and Heard 1969), South Carolina (Burton

1940; Bearden 1965), North Carolina (Radcliffe 1916-specimen in

Beaufort Laboratory but without data), Virginia (Jordan and Evermann 1896), and New York (holotype of isodon). Southwards the

records of isodon are likewise meager and confined to Cuba (Poey

1876 and also Manday 1968 who conunented that isodon has been

reported only once from that locality), British Guiana (Lowe

(McConnell) 1962), and southern Brazil (Sadowsky 1967 who noted

that his two specimens from Cananeia at lat. 25°S were a new record

for Brazil).

11

Reports of isodon from the eastern Atlantic cannot be regarded

as confirmed, and are probably based on other species including

particularly Carcharhinus brevipinna. Bigelow and Schroeder (1948)

cited Rochebrune (1883-85) and Metzelaar (1919) as references for

the occurrence of isodon off West Africa, but despite these listings

I note that Cadenat (1950) did not observe isodon off the Senegalese

coasts, and Poll (1951) likewise did not report it in the collection

of 21 species of sharks taken by the Expedition Oceanographique

Beige (1948-49) from the Equator south to lat. 22°30'S. Poll's (1951)

description of an Aprionodon as a new species, A. caparti, from

that expedition was, in fact, based on juvenile C. brevipinna. The

same may be true of Gonc;alves' (1955) listing of a small (650 nun)

specimen, as A. isodon, from Portuguese Guinea.

MATERIAL EXAMINED.-USNM 130651, female, 413 nun, Texas,

Galveston, 7-14 July 1940, 1. L. Baughman; USNM 126118, female,

453 nun, Mississippi, Biloxi Light, 4 July 1933, S. Springer; USNM

118457, female, 496 nun, Texas, Galveston, 14 July 1940, 1. L.

Baughman; MNHN 1037, male, 631 nun (holotype of Carcharias

(Aprion) isodon), New York, Milbert; USNM 143761, skinned-out,

female, ca. 1,500 nun, Florida, Salerno, January 1948, S. Springer.

Carcharhinus leiodon n.sp.

Figures 7, 8, Table 1

Holotype (the only specimen known) NMV 61465, immature male,

750 nun, from southern Arabia (Gulf of Aden) probably at Qishn

(variously spelt as Keschin, Kischin, or Gischin), collected by

W. Hein, 1902.

DIAGNOSIS.-Sharks lacking an interdorsal ridge; all fms with black

tips; snout moderately long and bluntly pointed; internarial width

1.1 in preoral length; origin of first dorsal fin slightly behind middle of inner pectoral margin; apex of first dorsal pointed; origin

of second dorsal slightly behind anal fin origin; height of second

dorsal 4.1 % TL and 0.8 in length of its rear tip; dental formula

16-3-16/15-3-15; upper teeth narrow, erect to slightly oblique, concave to notched medially, notched laterally, and smooth-edged; lower

teeth erect and smooth-edged; no obvious discrete series of enlarged

hyomandibular pores alongside corner of mouth; precaudal centra

115; caudal centra 83; total centra 198; diplospondyly begins above

anterior third of pelvic base; diplospondylous centra regular;

penultimate monospondylous centrum 0.5 times as long as wide.

The narrow, erect, and smooth-edged upper teeth of leiodon, when

compared with those of other Carcharhinus species, have close

counterparts only in isodon and in juvenile brevipinna, although comparably shaped teeth, but with serrated edges, occur also in

amblyrhynchoides, limbatus, and adult brevipinna. Other conunon

features which leiodon shares with these same four species include

the lack of an interdorsal ridge, a pointed snout, and rather large

gill openings. Carcharhinus leiodon differs from isodon in having

black fin tips, a much higher second dorsal fin (4.1 % TL versus

2.5-2.9% TL), and more precaudal vertebrae (115 versus 78-80).

It is readily separable from the black-tips amblyrhynchoides, limbatus, and brevipinna by having its first dorsal fin origin over the

middle of the pectoral inner margin (amblyrhynchoides and limbatus

have it over the pectoral axil, brevipinna over or behind the pectoral inner corner), by its greater number of precaudal vertebrae,

and to a less obvious extent by several differences in fin sizes and

proportions (see Garrick 1982 for comparative data on these

black-tips).

On external features alone, leiodon is most likely to be confused
(((((

a

b

Figure 7.-Carcharhinus leiodon n.sp., NMV 61-465, 750 mm TL, male from Gulf of Aden, Qishn: a, left side; b, underside of head; c, enlarged rigllt nostril.

Figure 8.-Carcharhinus leiodon n.sp., NMV 61-465, 750 mm TL, male from Gulf of Aden, Qishn: right upper and lower teeth (symphysis

to the right); inset teeth are enlarged fifth upper and lower teeth.

12
with melanopterus, and perhaps also with hemiodon. It agrees further with melanopterus in its number of precaudal vertebrae (115

versus 111-122) but differs in its pointed snout, upper tooth shape,

and dental formula (16/15 lateral teeth on each side versus 12 or 13/10

to 12). It is readily distinguished from hemiodon by its much shorter

first dorsal rear tip (4.4% TL versus 5.9-6.5% TL), its higher second dorsal (4.1 % TL versus 2.3-2.6% TL), and upper tooth shape.

In terms of vertebral numbers alone, the precaudal count of 115

for leiodon is encompassed only by counts for amblyrhynchos

(110-119), wheeleri (110-117), melanopterus (111-122), and leucas

(101-123), species which, apart from melanopterus discussed above,

differ trenchantly from leiodon in numerous other features.

DESCRIPTION (see also Table I).-Midline of back between dorsal fins smooth, lacking an interdorsal ridge. Upper precaudal pit

strongly developed, lower pit weak.

Dermal denticles slightly overlapping, ovoid in outline, wider than

long, each with three strong, longitudinal ridges and three, or

occasionally five, sharp-pointed, posterior marginal teeth.

Snout of moderate length and bluntly pointed in contour. Anterior

margin of eye above front of mouth. Nostrils strongly oblique,

~Iitlike, the anterior margin of each with a low, pointed lobe.

Dental formula 16-3-16/15-3-15. Upper teeth narrow, erect near

the center of the mouth but slightly oblique laterally, medial margins

notched to concave, lateral margins notched, both margins essentially smooth-edged, although there are slight irregularities basally. particularly on the lateral margins; three small symphysial teeth.

Lower teeth narrow, erect, with both margins deeply concave to

almost notched, and smooth-edged; three small symphysial teeth.

First dorsal fin of moderate height, erect rather than falcate, its

apex pointed; origin of first dorsal slightly behind middle of posterior

(inner) pectoral margin. Second dorsal fin large and high, almost

equal to anal fin; length of second dorsal rear tip 1.2 in its height;

origin of second dorsal slightly posterior to anal fin origin. Pectoral fin moderately short, weakly falcate, and pointed distally; origin

of pectoral fin below and between the fourth and fifth gill openings; outer corner of pectoral, when fin is adpressed to trunk so

that its anterior margin is horizontal, reaches to first dorsal axil.

Color after preservation is yellowish-brown above, and yellowish

on the underside, with a tongue of this paler underside color extending forward along the side of the trunk from the pelvic region

to below the first dorsal fin; the upper surface of the caudal peduncle behind the second dorsal is dusky. All fins are black-tipped, with

the black clearly demarcated from the background color; the black

markings on the apices of the first dorsal and pelvic fins are smaller

than those on the other fins; on the upper lobe of the caudal the

black tip is extended forwards along both margins as a narrow black

edging.

Vertebral count as in Table I. Centrum diameter considerably

greater than centrum length even in longest monospondylous centra at posterior of abdomen. Diplospondylous centra regular.

Diplospondyly begins above the anterior third of the pelvic base.

Length/diameter of penultimate monospondylous centrum is 0.51,

and length of penultimate monospondylous centrum/length of first

diplospondylous centrum is 1.22.

The size of the claspers (2.8 % TL) indicates that the specimen

is immature.

DISCUSSION.-Although my information on leiodon is based on

only one specimen, I have no hesitation in describing it as a new

species because it very clearly differs from all other species of Carcharhinus including even those that superficially are very similar

to it.

13

The collection data with the holotype are meager, giving the locality only as "Gischin," the collector as "Hein," and the date 1902.

I was unable to locate Gischin in atlases, but Rainer Hacker3 of the

Vienna Museum informed me that the name may be an old spelling

or a misspelling for Qishn in southern Arabia, which latter region

was where Wilhelm Hein collected specimens, including the

holotype, at the beginning of this century. Other alternative spellings in older atlases are Keschin and Kischin.

Etymology ofthe Name.-leiodon is a noun in the nominative singular

in apposition, formed from Greek leios, adjective = smooth, and

Greek (Ionic) odon, noun, masculine = tooth.

Carcharhinus hemiodon (Valenciennes in

Miiller and Henle, 1841)

Figures 9, 10, Table 2

Carcharias (Hypoprion) hemiodon Valenciennes in Muller and

Henle, 1841:35, plate 19 (teeth). Four spirit specimens in the Paris

Museum, from Belanger. India-Malabar and Pondicherry.

Hypoprion atripinnis Chu, 1960:80, figures 75-76 (not seen; data

from Chu (1962:26, fig. 19) in which four females, 519 to 675

mm, and two males. 542 and 564 mm, are listed). South China

Sea.

DIAGNOSIS.-Small sharks. probably up to 1.0 m long, with or

without an interdorsal ridge; pectoral, lower lobe of caudal, and

to a lesser extent second dorsal, black-tipped; upper caudal leading

margin and tip and apex of first dorsal dusky-edged; snout moderately

long and bluntly pointed; internarial width 1.2-1.3 in preoral length;

origin of first dorsal fin above or slightly in front of middle of inner

pectoral margin; apex of first dorsal pointed; rear tip of first dorsal

5.9-6.5 % TL; origin of second dorsal one-third to almost halfway

along anal base; height of second dorsal 1.9-2.6% TL and 1.5-2.3

in length of its rear tip; dental formula usually 14-1 or 2-14/13-1 or

2-13 but may be 14-1 or 2-14/12 to 14-1 or 2-12 to 14; upper teeth

narrow, erect to slightly oblique, notched laterally and notched to

concave or straight medially, with very large serrae basally but

smooth-edged distally; lower teeth erect and smooth-edged; no obvious discrete series of enlarged hyomandibular pores alongside corner of mouth; precaudal centra 69-71; caudal centra 78-84; total centra

147-155; diplospondyly begins from between pelvic axil and tip to

midway between pelvic tip and anal fin; diplospondylous centra

regular; penultimate monospondylous centrum 1.1-1.2 times longer

than wide.

The black fin tips of hemiodon, coupled with its distinctively long

first dorsal rear tip (5.9-6.5 % TL) and features of its upper teeth

(teeth smooth-edged distally but with large serrae basally), effectively separate it from all other Carcharhinus species including even

the blad.-llpped species (amblyrhynchoides, brevipinna, limbatus,

melanopterus, sorrah, and C. leiodon n.sp.) with which it could,

at first glance, be confused. Of these latter, melanopterus comes

closest to it in having a long first dorsal rear tip (3.8-5.0% TL), but

melanopterus differs immediately in its much blunter snout contour and higher second dorsal fin.

NOMENCLATURAL DISCJSSION.-The spirit-preserved holotype

and three paratypes of ;.emiodon Valenciennes in Muller and Henle

(1841) in the Paris Museum permit amplification of the original

JR. Hacker. former Curator of Fishes, Naturhistorisches Museum, Wein, Burgring

7, A-l0l4 Vienna, Austria, pers. commun. July 1980.
c

b

Figure 9.-Carcharhinus hemiodon, SU 14501, 553 mm TL, male from India, Calicut: a, left side; b, underside of head; c, enlarged right nostril.

Figure 10.-Carcharhinus hemiodon, SU 14501, 553 mm TL, male from India, Calicut: right upper and lower teeth (symphysis to the right);

inset teeth are enlarged fifth upper and lower teeth.

14
Table 2. -- Carcharhinus hemiodon, proportional dimensions in percent of total length.

Snout tip to: outer nostrils

eye

mouth

1st gill-opening

3rd gill-opening

5th gill-opening

pectoral origin

pelvic origin

1st dorsal origin

2nd dorsal origin

anal fin origin

upper caudal origin

lower caudal origin

Nostrils: distance between inner corners

Mouth: width

length

Labial furrow lengths: upper

lower

Gill-opening lengths: 1st

3rd

5th

Eye: horizontal diameter

1st dorsal fin: length base

posterior margin

height

2nd dorsal fin: length base

posterior margin

height

Anal fin: length base

posterior margin

height

Pectoral fin: length base

anterior margin

distal margin

greatest width

Pelvic fin: length base

anterior margin

distal margin

length claspers

Caudal: length upper lobe

length lower lobe

Trunk at pectoral origin: width

height

Dental formula

Vertebrae: precaudal

caudal

total

d 368 nun!.

India

Malabar

MNHN 7774

3.9

7.2

7.2

22.7

21.9

46.4

29.9

61. 2

59.8

72.0

70.6

5.7

7.7

5.4

0.5

0.5

3.3

2.4

10.3

6.2

9.4

3.5

4.5

2.4

4.3

4.1

3.1

6.5

16.3

10.8

8.7

5.2

5.7

4.5

2.6

28.8

13.2

10.8

9.5

14-1-14

d 444 nun

India

Canara

BMNH 89. 2 . 1. 41 74

3.8

7.2

7.2

17 .3

19.8

22.3

21.6

46.8

29.0

61.9

59.9

72.3

71.1

5.8

8.0

4.5

0.5

0.5

3.2

3.7

3.2

2.3

9.9

5.9

10.9

2.9

4.3

2.3

4.5

3.9

3.2

6.2

17.1

12.6

8.6

4.6

5.2

5.2

2.7

28.1

12.6

14-1-14

I4=1-IT

70

84

154

d 467 mID 2. d 553 nun 9 665 nun

India India India Ponciicherry Calicut Calicut

MNHN 1040 su 14501 BMNH 89.2.1.4171

3.5 3.3 3.6

6.5 7.0 7.3

6.5 7.2 7.4

18.6 17.2 18.5

21.2 19.7 21. 2

23.6 21. 7 23.2

22.9 21.0 22 .3

47.8 46.1 46.9

30.0 29.5 29.6

62.7 62.4 61. 5

60.8 60.5 60.1

72 .3 72.3 71. 9

71. 5 70.9 70.7

5.7 5.8 5.7

9.2 8.4 7.8

5.5 5.1 5.1

0.6 0.5 0.6

0.6 0.5 0.4

3.1 2.8

3.6 3.2 3.8

2.9 2.7

2.2 2.3 2.1

10.3 10.4 10.5

6.0 5.9 6.5

9.6 10.8 11.6

2.7 3.4 3.0

4.3 4.2 3.9

1.9 2.4 2.6

4.3 4.2 4.7

4.1 4.2 3.8

2.8 3.2 3.8

5.8 6.3 6.0

16.8 19.2 18.6

11.8 13.7 15.2

9.2 9.8 10.2

4.6 5.4 5.3

4.8 5.9 5.6

4.5 5.7 6.0

2.4 2.5

27.2 28.0 28.3

12.6 13.0 12.8

11. 3 11. 7

10.7 1l.5

14-1-14 14-2-14 14-2-14

rr=T=TI

69 71 71

78 84 83

147 155 154

1. Para type of Carcharias (~) ~.

2. Holotype of Carcharias (~) hemiodon.

15
description, which although adequate was not accompanied by an

illustration other than of the teeth.

I have not seen Chu's (1960) original description of his atripinnis

from the South China Sea, but his later description (1962) and illustrations (lateral view and underside of head) agree so well with

hemiodon that I find no reason for regarding atripinnis as distinct

from hemiodon. Chu (1962) compared atripinnis only with macloti

from which he found obvious differences.

Gill (1862) designated hemiodon as the type-species of a new genus

Hypoprionodon differing from Hypoprion Muller and Henle in the

more anterior position of the first dorsal fin relative to the pectoral

fins. Subsequent authors have not found this generic separation

compelling.

DESCRIPTION (see also Table 2).-Small sharks, growing to about

1 m TL. Midline of back between dorsal fins with or without a low

interdorsal ridge. Upper precaudal pit strongly developed, lower pit

weak.

Dermal denticles in small specimens overlapping, ovoid in outline,

wider than long, each with three strong longitudinal ridges and three,

or occasionally five, rather short, posterior marginal teeth.

Snout of moderate length and bluntly pointed: anterior margin

of eye above or slightly forward of front of mouth. Nostrils strongly oblique, with rather broadly ovate apertures, the anterior margin

of each with a narrow, pointed lobe.

Dental formula 14-1 or 2-l4/13-1 or 2-13 in four of six specimens

counted, 14-1-14/12-1-12 in one, and 14-1-14/14-1-14 in one. Teeth of

an immature male as in Figure 10, where the upper teeth are narrow, erect near the center of the mouth but increasingly oblique

laterally, their lateral margins deeply notched, their medial margins

notched in the teeth near the center of the mouth but weakly concave to straight in those towards the corner of the mouth; two to

four very large basal serrae on the lateral margin of each tooth, and

a comparable number of rather smaller and less well defined basal

serrae on the medial margin [these medial serrae are lacking in

smaller specimens judging by descriptions in Muller and Henle (1841)

and Day (1889)]; distally both margins of each tooth are smoothedged; one or two small symphysial teeth. Lower teeth of the same

specimen narrow, more erect than the upper, with both margins

notched, and smooth-edged except for some slight basal irregularities, particularly on the lateral margins; one or two small symphysial teeth.

First dorsal fin moderately high, erect to weakly falcate, its apex

pointed, its rear tip noticeably long (5.9-6.5% TL); origin of first

dorsal above or slightly in front of the middle of the posterior (inner) margin of the pectoral fin. Second dorsal fin moderately low

but long, and considerably lower than the anal fin; length of second dorsal rear tip 1.5 to 2.3 (mean 1.9 in five specimens) times

its height; origin of second dorsal behind anal fin origin, ranging

from one-third to almost halfway along anal base. Pectoral fin

moderately short, falcate, pointed distally; origin of pectoral fin

below the fourth gill opening; outer corner of pectoral, when fin

is adpressed to trunk so that its anterior margin is horizontal, reaches

from almost to first dorsal axil to as far back as one-third along

first dorsal rear tip.

After preservation in alcohol, the color of the back and sides is

dark greyish while the underside is pale; on some specimens a tongue

of the paler color extends forward along the side from the pelvic

region to below the first dorsal fin. The pectoral fin and the lower

lobe of the caudal are extensively black-tipped, and to a lesser extentthe apex of the second dorsal is dusky to black; the upper caudal

leading margin and tip and the apex of the first dorsal are

16

dusky-edged.

Vertebral counts of four specimens as in Table 2. One further

specimen (BMNH 1889.2.1.4172 from Madras) has a count of 70

precaudal, 84 caudal, and a total count of 154 centra. Centrum

diameter greater than centrum length except in longest monospondylous centra at posterior of abdomen where the length is about

equal to or slightly greater than the diameter. Diplospondylous centra

regular. Diplospondyly begins from between the pelvic axil and tip

to as far back as midway between the pelvic tip and anal fin origin.

Length/diameter of penultimate monospondylous centrum is 1.08

to 1.19 (mean 1.14 in five specimens), and length of penultimate

monospondylous centrum/length of first diplospondylous centrum

is 1.24 to 1.61 (mean 1.40 in five specimens).

The smallest specimens seen by me were a female of 317 mm TL

and a male of 368 mm (paratype), while the largest were a female

of 1,020 mm (mounted skin) and an immature male of 553 mm.

These sizes encompass specimens mentioned in the literature

available to me, except for Boulenger's (1889) report of an adult

female of 8 ft 4 inches (2,540 mm) from Muscat which was undoubtedly a misidentification insofar as hemiodon appears to be an

inshore species and hence could be expected to be represented in

collections by other comparably large specimens were it to grow

to that size. Because of the overall paucity of material of hemiodon

and the lack of any data on size at maturity and reproduction, there

is no gauge by which to estimate the approximate maximum size

except that if the smallest specimens seen (female, 317 mm and male,

368 mm) were free-living and not embryos, then it is likely that

maximum size does not greatly exceed 1 m. Clasper length of the

largest male examined (553 mm TL and immature) was 2.5% TL,

and in three other immature males, 368 to 467 mm (induding the

holotype and a paratype) clasper length ranged from 2.4 to 2.7%

TL. Compagno (1984) reported immature specimens up to 600 mm

long.

DISTRIBUTION (see also Material Examined).-Tropical IndoPacific, virtually confined to the Indo-Australian archipelago.

Specimens I have examined have been from the Gulf of Oman

(Muscat) in the west, eastwards at both sides of India (Malabar,

Canara, Madras, and Pondicherry) which is the type locality, and

southwards at Borneo and Java (Batavia). Literature reports, frequently as mere listings and hence not verifiable, extend this distribution to Calcutta (Day 1878), Vietnam (Chevey 1929; Tirant 1929),

South China Sea (Chu 1962-as atripinnis), Philippines (Meyer 1885

and Elera 1895 according to Fowler (1941) though I have not seen

these accounts), Indonesia (Damar Island in the Moluccas from

Weber 1913 and north Celebes from Meyer 1885-latter not seen),

and northwest New Guinea at Waigeu (Weber 1913). As well there

are unsubstantiated and conflicting reports of hemiodon from

Australia, dating from Macleay (1878) who identified it from Port

Darwin but later (1882) amended his identification to Carcharhinus

melanopterus. Zeitz (1888) subsequently reported a 17-inch (432 mm)

specimen from Port Adelaide Creek, South Australia, as hemiodon,

noting that as its upper teeth were denticulated only at the base,

it was referable to Hypoprion according to criteria from Gunther

(1870). Whitley (1934) listed H. hemiodon in the Australian fauna.

Although Day (1878) reported that hemiodon ascended rivers such

as the Hooghly at Calcutta, and Tirant (1929) observed that he had

seen hemiodon several times in the Saigon River above Saigon at

Thudaumot, it remains to be established whether these reports indicate that hemiodon can tolerate substantially reduced salinity.

MATERIAL EXAMINED.-RNH 7387, female, 317 mm, Batavia,
1852, Bleeker; MNHN 7774, two males, 368 and 3W mm (paratypes

of Carcharias (Hypoprion) hemiodon), India, Malabar, Belanger;

BMNH 89.2.1.4172, female, 435 mm, India, Madras, F. Day;

MNHN 1042, female, 437 mm (paratype of Carcharias (Hypoprion)

hemiodon), India, Pondicherry, Belanger; BMNH 89.2.1.4174, male,

444 mm, India, Canara, F. Day; MNHN 1040, male, 467 mm

(holotype of Carcharias (Hypoprion) Hemiodon) , India, Pondicherry, Belanger; ISZZ 6967, mounted skin of female, 480 mm,

East Indies, Besnard; NMV -, female, 540 mm, Borneo, 18W; SU

14501, male, 553 mm, India, Calicut, 1941, A. W. Herre; BMNH

89.2.1.4171, female, 665 mm, India, Calicut, F. Day; BMNH -,

mounted skin of female, ca. 1,020 mm, Muscat, A. S. G. Jayrakar.

Carcharhinus macloti (Muller and

Henle, 1841)

Figures 11, 12, Table 3

Carcharias (Hypoprion) Mac/oti Muller and Henle, 1841:34-35, plate

iO (lateral view, underside of head, teeth and dermal denticles).

One dried specimen in the Leyden Museum, from Macklot. New

Guinea.

DIAGNOSIS.-Small sharks, up to 1.0 m long, usually with an interdorsal ridge in preserved specimens; no prominent black tips on

the fins, but the leading margins of the second dorsal and the upper

caudal, and sometimes the first dorsal and pectoral, have a narrow

dusky or black edge; trailing margins of pectoral, pelvic, anal, and

lower caudal white or pale; snout very long (8.7-10.3% TL) and sharply pointed; internarial width 1.7 -1.9 in preoral length; origin of first

dorsal fin above posterior one-third or tip of inner pectoral margin;

apex of first dorsal pointed; rear tip of first dorsal 5.3-7.1 % TL; origin

ofsecond dorsal above middle of anal base; height of second dorsal

1.6-2.1% TL, and 2.3-2.6 in length of its rear tip; dental formula

commonly 14-1 to 3-14/13-1-13 but may be 14 or 15-2-14 or 15/13 or

14-1-13 or 14; upper teeth narrow, erect to oblique, concave to notched

laterally, concave to straight or convex medially, with very large serrae basally but smooth-edged distally; lower teeth erect to slightly

oblique, and smooth-edged; a discrete series of 7-12 enlarged

hyomandibular pores alongside corner of mouth; precaudal centra

68-71; caudal centra 79-84; total centra 149-154; dipJospondyly usually begins at pelvic origin but may be as far back as two-thirds along

pelvic base; diplospondylous centra regular except for one or two

enlarged centra alternating with the normal centra anteriorly;

penultimate monospondylous centrum 1.3-1.6 times longer than wide.

This species, together with hemiodon and signatus, differs from

all other Carcharhinus in having upper teeth which are smooth-edged

distally, the only serrations present being very large serrae basally.

Carcharhinus mac/oti is separable from hemiodon in snout length

(8.7-10.3 % TL in mac/oti, 7.2-7.4 % TL in hemiodon) and in lacking

prominent black tips on the fins, and from signatus in having a much

longer first dorsal rear tip (5.3-7.1 % TL in mac/oti, 3.6-4.6% TL

in signatus). It further differs from both these species, and from

all other Carcharhinus species except bomeensis, in having a discrete

series of enlarged hyomandibular pores alongside each corner of

the mouth. Its resemblance to borneensis includes not only this

feature but also several other shared attributes such as the unusually long, low second dorsal fin originating over the middle portion

of the anal fin base, the nipplelike nasal lobes, and the presence

of large basal serrae on the upper teeth. However, it can be

distinguished from blJmeensis by Its longer snout (8.7-10.3 % TL versus 4.1-5.2 % TL in borneensis), by having the upper teeth smoothedged distally, and to a lesser extent by its longer pectoral fin and

17

longer first dorsal rear tip.

NOMENCLATURAL D1SCUSSION.-Although I have not examined the holotype of mac/oti Muller and Henle (1841), the original

description of this very distinctive little shark plus the accompanying illustrations leave no doubt as to its identity. There are no primary

synonyms of mac/oti. Gill (1862) designated mac/oti as type-species

of Hypoprion Muller and Henle, 1841, an action that seems to have

been overlooked by subsequent workers (Fowler 1941; Bigelow and

Schroeder 1948) who attributed that type-species designation to Jordan and Gilbert (1883).

DESCRIPTION (see also Table 3).-Small sharks, probably growing to 1 m TL. Midline of back between dorsal fins with a low interdorsal ridge in most preserved specimens and perhaps in all in life.

Upper precaudal pit strongly developed, lower pit weak.

Dermal denticles overlapping, subcircular to ovoid in outline,

slightly wider than long, each with three strong longitudinal ridges

and corresponding short posterior marginal teeth in small specimens;

in adults the denticles are essentially the same but a few denticles

have five posterior teeth.

Snout very long (8.7-10.3 % TL) and sharply pointed. Anterior

margin of eye forward of front of mouth by a distance equal to onethird to half of eye diameter. Nostrils strongly oblique, with rather

broadly ovate apertures, the anterior margin of each with a narrow,

pointed lobe. A discrete longitudinal row of enlarged hyomandibular

pores lateral to each corner of the mouth, their number ranging from

7 to 12 (mean of 8.6 on left side, 9.0 on right side in five specimens).

Dental formula 14-1 to 3-14/13-1-13in three of seven specimens

counted, and within the range 14 or 15-2-14 or 15/13 or 14-1-13 or

14 in the remaining four. Upper teeth narrow, erect near center of

mouth but increasingly oblique laterally, their lateral margins concave to notched, their medial margin5 concave in the teeth near the

center of the mouth but straight to convex or sinuous in those towards

the corner of the mouth; distally both margins are smooth-edged

but basally there are very large serrae, particularly on the lateral

margin, but their number is variable and in part related to size or

age; in four juveniles and subadults (both sexes) of 323-526 mm

TL from China, Hong Kong, and the Gulf of Aden, there were 1-2

serrae laterally and 0-1 medially, whereas in a mature female of718

mm from Burma there were up to 4 laterally and 3 medially; contrasting with this, a mature male of 734 mm from Borneo had not

more than 2 or 3 laterally (and these poorly defined) and 0 medially; the difference between these two adults may reflect either sexual dimorphism or geographic variation; one to three small symphysial teeth. Lower teeth erect to slightly oblique, with both margins

deeply concave to notched, and smooth-edged; one small symphysial

tooth.

First dorsal fin low, erect to slightly falcate, its apex pointed, its

rear tip very long (5.3-7.1 % TL); origin of first dorsal at least twothirds back along posterior (inner) pectoral margin in juveniles, and

over posterior (inner) pectoral corner in larger specimens. Second

dorsal fin very low and long, and considerably lower than the anal

fin; length of second dorsal rear tip 2.3-2.6 (mean 2.5 in seven

specimens) times its height; origin of second dorsal above middle

of anal base. Pectoral fin short, moderately falcate, pointed distally;

origin of pectoral fin below fourth gill opening; outer corner of pectoral, when latter is adpressed to trunk so that its anterior margin

is horizontal, reaches at least two-thirds along first dorsal base in

small specimens and to as far as first dorsal axil in adults.

After preservation in alcohol, the color of the back and sides is

dark grey while the underside is white or pale, and a tongue of this
d c

(((((

b

a

Figure ll.-Carcharhinus mac/oli: a, left side of USNM 197385, 734 mm TL, male purportedly from Borneo; b, underside of head of same; c, enlarged right nostril

of same; d, mouth region of SU 14488, 718 mm TL, female from Burma to show arrangement of enlarged hyomandibular pores.

Figure 12.-Carcharhinus mtu:loli: right upper and lower teeth (symphysis to the right) of USNM 197385, 734 mm TL, male purportedly from Borneo; inset teeth

a and b are enlarged fifth upper and lower teeth of same; c, fourth upper tooth of SU 14488, 718 mm TL, female from Burma.

18
Table 3. - Carcharhinus mac loti , proportional dimensions in percent of total length.

, 323 mm , 490 mm d 518 mm d 526 mm d 526 mm , 718 mm d 734 mm

Gulf of Hong }(omj China Hong }(ong India Burma ? Borneo Aden Chusan Is. Madras South Moscos

BMNH 1925.7.20.9-13 ISZZ 5799 su 14Ul SU 12988 BMNH 89.2.1.4170 SU 14488 USNM 197385

Snout tip to: outer nostr ils 5.0 5.5 4.8 4.8 5.6 5.0 4.8

eye 8.8 9.1 8.1 8.2 9.0 8.'3 8.0

mouth 10.3 9.8 9.3 9.1 9.8 9.2 8.7

1st gill-opening 21. 3 20.2 19.1 19.2 20.5 20.2 20.0

3rd gill-opening 23.5 22.4 21. 0 21. 5 22.6 22.4 22.2

5th gill-opening 25.2 24.6 22.8 23.0 24.8 24.1 23.7

pectoral origin 24.2 24.3 22 .0 22.4 24.1 23.4 23.2

pelvic origin 48.0 48.5 46.7 48.3 49.4 49.4 47.9

1st dorsal origin 31.9 32.2 31.3 30.8 32.5 32.3 31. 2

2nd dorsal orig in 61.9 62.2 62.0 62.3 63.8 65.0 63.7

anal fin origin 59.7 60.8 60.1 60.5 62.4 62.4 61. 7

upper caudal origin 70.3 71.4 71.4 72.0 72.8 73.6 72.9

lower caudal origin 69.3 70.5 69.9 71. 3 71. 3 72.5 72.0

Nostrils: distance between inner corners 5.6 5.1 5.4 4,9 5.1 5.4 5.0

Mouth: width 7.0 7.1 6.6 6.7 7.6 7.9 7.2

length 4.8 5.1 4.4 4.5 4.8 5.0 4.5

Labial furrow lengths: upper 0.6 O•• 0.' 0.' 0.6 O•• 0.5

, lower 0.5 0.4 0.3 0.' 0.5 0.6 0.5

Gill-opening lengths: 1st 2.7 3.0 2.2 2.9 2.9

3rd 2.9 2.9 3.5 2.7 3.5 3.3 3.1

5th 2.2 2.9 2.9 2.9 2.5

Eye: hor ixontal diameter 3.1 2.3 2.3 2.1 2.5 2.0 1.9

1st dorsal fin: length base 9.3 8.3 8.5 8.7 8.7 9.0 9.0

poster ior margin 5.6 5.7 5.6 5.3 6 .• 7.1 6.3

height 7.1 7.5 7.7 7.7 8.9 8.8+ 8.2

2nd dorsal fin: length base 2.9 2,7 2.7 2.9 2.9 2.8 2.9

posterior margin '.2 4 .• '.2 '.2 '.8 5.2 • .8 height 1.8 1.7 1.7 1.6 2.1 2.0 1.8

Anal fin: length base '.2 3.5 3.7 3.8 3.2 '.2 3.7

poster ior marg in 4.2 4.1 •. 0 •. 1 4.8 5.0 • .8 height 2.6 2.2 2.3 2.5 2.8 2.6 2.7

Pectoral fin: length base 5.0 '.9 5.8 5.4 5 .• 5.2 5.3

anterior margin ".5 15.1 14 .5 13 .5 15.2 16.1 15.4

distal margin 9.9 10.6 10.2 10.2 10.6 13.0 11.8

greatest .... idth 8 .• 7.6 7.6 8.2 7.9

Pelvic fin: length base • .0 4.1 4.1 3.9 •. 0 •. 6 ·.. anter ior margin • .6 ... 4.3 3.9 ... 5.2 '.3

distal marg1n • .6 •. 1 4.2 '.2 •. 0 5.2 '.5

length claspers 2.1 2.3 2.5 9.1

Caudal: length upper lobe 29.4 28.6 28.6 28.0 27.6 27.1 27.1

length lower lobe 10.8 10.6 11. 4 10.1 11. 0 11.8 11.6

Trunk at pectoral origin: width 10.5 9.2 9.5 9.5 10.2 9.9

height 10.5 9.2 8.7 9.1 9.9 9.7

Dental formula 14-2-14 14-2-14 14-2-14 14-2-14 14-3-14 15-2-14 15-2-15

== == l'4"=1-T4 == == 14-1-13 14-1-14

Vertebrae: precaudal 71 70 71 68 70 70 70 caudal 79 8. 83 82 79

154 82 80 total 150 154 150 ,.9 152 150

19
paler color may extend forward along the side from the pelvic region

to below the first dorsal fin. There are no prominent dark markings

on the fins, but in most specimens the leading margin of the second

dorsal and both margins of the upper caudal are narrowly edged

with duskyness or black, and in some specimens there is a similar

dark edging on the leading margins of the first dorsal and pectoral;

in most specimens the trailing margins of the pectoral, pelvic, anal,

and lower lobe of caudal are white or pale.

Vertebral counts as in Table 3. Centrum diameter greater than centrum length anteriorly, but this relationship reversing in posterior

half of abdomen where the length of the longest monospondylous

centra is considerably greater than the diameter. Diplospondylous

centra essentially regular except that most specimens have one or

two longer centra interposed between the normal centra anteriorly.

Diplospondyly, as evidenced by position of first short centrum,

begins at pelvic fin origin in five of seven specimens, at one-third

along pelvic base in one, and two-thirds along pelvic base in one.

Length/diameter of penultimate monospondylous centrum is 1.26

to 1.61 (mean 1.43 in seven specimens), and length of penultimate

monospondylous centrumllength first diplospondylous centrum is

1.63 to 2.08 (mean 1.80 in seven specimens).

The smallest specimens seen by me, and smaller than any reported

in the literature, were two females of 320 and 323 mm TL and three

males of 348 to 370 mm, all listed under the same collection number

(BMNH 1929.7.20.9-13). The largest specimens seen were a mature

male of 734 mm TL and a female of 790 mm. A male of 845 mm

in Nakamura's (1936) account is the only specimen of either sex

reported in the literature available to me that exceeds the size of

my material. In the male it is likely that maturity is reached at a

length of 700 mm or less. This estimate is based firstly on my

material in which three males of 518 to 526 mm were immature with

clasper lengths of 2.1 to 2.5 % TL whereas one of 734 mm was obviously mature with a clasper length of 9.1 %, and secondly on the

holotype which, as illustrated, was mature with a clasper length equal

to about 7.5 % at a total length of 27.5 inches, which corresponds

to 698 mm if Muller and Henle (1841) used imperial measures or

724 mm if they used Vienna measures. Nakamura (1936) illustrated

a mature male of 845 mm in which the clasper length appears to

be about 7.5 %. For females my only information on maturity is from

a 718 mm specimen which was clearly mature with well developed

shell glands and uteri containing remnants of yolk. Judging by the

above evidence on size at maturity it is likely that the maximum

size of macloti does not exceed I m. Campagno (1984) reported that

the number of embryos "is usually 2 (one per uterus), size at birth

45 to 50 cm."

DISTRIBUTION (see also Material Examined).-Northern Indian

Ocean and tropical Indo-Pacific including most ofthe Indo-Australian

archipelago and probably Australia itself. Specimens seen by me

have been from Aden, both coasts of India (Malabar and Madras),

Burma (S. Moscos Group), Hong Kong, China (including Chusan

Island), and North Sulu Sea off Borneo. Literature records, in some

cases as mere listings of macloti, which extend and fill out this

distribution include Kenya (Compagno 1984), Bombay (Setna and

Sarangdhar 1946), Pakistan (Qureshi 1977-not seen), Ceylon (Mendis 1954), South China Sea (Chu 1962), Taiwan (Nakamura 1936

and Chen 1963), New Guinea (type-locality-Muller and Henle 1841,

and with several other listings including Papua, the D'Entrecasteaux

Group and New Britain from Munro 1958) and Australia (see below).

Fowler (1941) also included references for Mekran (Zugmayer 1913),

Malaya (Fowler 1938), and the Philippines (Elera 1895), but I have

not seen these. Australian listings date from Ramsay (1881) and

20

Ogilby (1889) who reported macloti from Port Jackson, New South

Wales, but I have seen no specimens to substantiate its occurrence

there. Whitley (1940) noted that a record of macloti from the Gulf

of Carpentaria, Northern Territory, by Paradice and Whitley (1927)

was in error, being based on Protozygaena taylori, a species of

Rhizoprionodon. However, McKay' informs me that a long-snouted

Hypoprion is present off Darwin and this is very likely to be macloti

in view of its occurrence at nearby New Guinea.

MATERIALEXAMINED.-BMNH 1929.7.20.9-13, two females, 320

and 323 mm, and three males, 348 to 370 mm, Gulf of Aden, A.

Ehrenreich; RNH 4575, female, 450 mm, from Bleeker; RNH 8576,

female, 480 mm, India, Malabar; ISZZ 5799, female, 490 mm, Hong

Kong; SU 14111, male, 518 mm, China, Chusan, A. W. Herre; SU

12988, male, 526 mm, Hong Kong, W. Finch; BMNH 89.2.1.4170,

male, 526 mm, India, Madras, F. Day; NMV -, female, 537 mm,

India, Madras, 1886, Day; SU 14488, female, 718 mm, Burma, South

Moscos Group, November 1940, A. W. Herre; USNM 197385, male,

734 mm, Manila Fish Market, purportedly caught by fishermen off

Borneo, North Sulu Sea, March 1962; NMV 24449 (old number),

female, 790 mm, China, 1905, Konsul Post.

Carcharhinus signatus (Poey, 1868)

Figures 13, 14, Table 4

Hypoprion signatus Poey, 1868:452, plate 4, figures 7-8 (teeth).

Based on a set of jaws only. Cuba.

Hypoprion longirostris Poey, 1876:394-395, plate 9, figures 8-9

(teeth). Male, 2,266 mm. Cuba.

Hypoprion bigelowi Cadenat, 1956:539-545, 5 figures. Female, 1,627

mm. Between the limits of the French Guinea and Portuguese

Guinea coasts.

DIAGNOSIS.-Large sharks, up to 2.55 m long, with an interdorsal

ridge; no prominent black tips on the fins, but in small specimens

most fins are dusky margined and in adults the underside of the

pectoral is dusky towards its tip; snout very long (8.5-10.3% TL),

its tip sharply rounded; internarial width 1.5-1.8 in preoral length;

origin of first dorsal fin varying from above middle of inner pectoral margin to as far back as inner pectoral corner; apex of first

dorsal pointed; rear tip of first dorsal 3.6-4.6% TL; origin of second dorsal varying from above anal fin origin to about halfway

along anal base; height of second dorsal 1.6-1.9% TL, and 2.0-2.3

in length of its rear tip; dental formula 15 or 16-2-15 or 16/14 to 16-1-14

to 16; upper teeth narrow, erect to oblique, notched laterally, straight

to convex medially, with large serrae basally but smooth-edged distally; lower teeth erect to slightly oblique, and smooth-edged; no obvious discrete series of enlarged hyomandibular pores alongside corner of mouth; precaudal centra 98-104; caudal centra 80-87; total

centra 182-191; diplospondyly begins about one-third along pelvic

base; diplospondylous centra regular; penultimate monospondylous

centrum 0.6-0.7 as long as wide.

The upper teeth ofsignatus (smooth-edged distally but with large

serrae basally) together with the combination of a long snout

(8.5-10.3 % TL) and an only moderately long first dorsal rear tip

(3.6-4.6% TL) enable it to be distinguished from all other Carcharhinus species including the only other two species (hemiodon

and macloti) with comparable upper teeth.

'R. J. McKay. Curator of Fishes. Queensland Museum. Gregory Terrace, Fortitude

Valley. Queensland 4006, Australia, pers. commun. November 1980.
a

c~. '. ,':·.. ·.i·:. ':" .',:'

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

..... : ::>..::: '

Figure 13.-Carcharhinus signatus, USNM 196131, 1,740 mm TL, female from Northwest Atlantic: a, left side; b, underside of head; c, enlarged right nostril.

Figure 14.-Carcharhinus signatus, USNM U2S82, 2,286 mm TL, male from Bahamas: right upper and lower teeth (symphysis to the

right); inset teeth are enlarged fifth upper and lower teeth.

21
Table 4. -- Carcharhinus signatus, proportional dimensions in percent of total length.

564 mm 9 930 mm 9 998 mm 9 1590 mm l. 9 1740 mm

West North West East East North West

Atlantic Atlantic Atlantic Atlantic Atlantic

USNM 197373 USNM 38508 MRAC 80256 MNHN 55-4915 USNM 196131

Snout tip to: outer nostrils 5.5 5.4 4.9 5.0 5.1

eye 9.2 9.2 8.7 6.4 8.8

mouth 10.3 9.5 9.1 8.5 9.1

1st gill-opening 21. 8 20.2 19.2 20.1 21.0

3rd gill-opening 23.9 22.8 22.2 22.9 23.7

5th gill-opening 25.5 24.5 24.1 25.2 25.5

pectoral origin 24. 23.6 23.0 24.7 24.3

pelvic origin 50. 50.9 47.6 51. 6 52.5

1st dorsal origin 33.3 33.7 31. 3 32.6 32.7

2nd dorsal origin 62.9 65.3 61.1 64.4 59.3

anal fin origin 62.6 63.4 59.6 63.8 59.2

upper caudal origin 72.7 74.3 71. 2 73.3 73.9

lower caudal origin 71. 8 73.3 70.2 72.2 72.8

Nostrils: distance between inner corners 5.8 5.2 5.4 4.8 5.2

Mouth: width 7.4 7.1 7.7 7.0 7.2

length 4.6 5.1 4.5 5.1 4.5

Labial furrow lengths: upper 0.4 0.5 0.6 0.5 0.6

lower 0.4 0.6 0.5 0.6 0.5

Gill-opening lengths: 1st 2.7 2.2 2.4 3.0 2.6

3rd 3.0 2.7 3.2 3.3 3.1

5th 2.0 1.7 1 9 2.1 2.0

Eye: horizontal diameter 3.1 2.3 2.2 1.9 1.8

1st dorsal fin: length base 8.6 8.8 9.3 9.0 9.0

posterior margin 3.6 3.9 4.6 3.7 4.4

height 6.4 7.4 8.1 8.4 7.9

2nd dorsal fin: length base 3.3 2.4 2.9 2.5 2.6

posterior margin 3.6 3.7 4.0 3.6 4.0

height 1.6 1.9 1.8 1.8 1.8

Anal fin: length base 3.5 3.0 4.3 3.5 3.0

posterior margin 3.5 3.4 3.6 3.5 3.9

height 2.0 2.2 2.1 2.4 2.1

Pectoral fin: length base 5.3 5.7 6.0 5.3 6.1

anterior margin 15.8 16.8 19.7 19.0 18.3

distal margin 9.6 12.9 15.0 15.8 15.5

greatest width 8.2 8.6 9.6 9.7 9.4

Pelvic fin: length base 5.1 4.5 4.7 4.8 4.6

anterior margin 5.1 4.7 5.1 5.1 5.3

distal margin 4.1 4.2 5.1 5.5 4.5

length claspers 1.9

Caudal: length upper lobe 27.0 26.1 29.0 27.3 26.3

length lower lobe 11. 2 11. 3 12.7 12.3 12.2

Trunk. at pectoral origin: width 11. 3 U.5 11.8 10.7

height 10.3 11.2 11.5 11.5

Dental formula 15-2-15 15-2-15 15-2-15

rs=r=rs IT=""i-=T4 B'=I=15

Vertebrae: precauda1 101 104 98

caudal 87 87 84

total 188 191 182

l. Holotype of Hypoprion !?igelowi.

22
NOMENCLATURAL DISCUSSION.-Poey (1868) described signatus

from jaws alone, and illustrated an upper tooth in which the medial

margin had about six basal serrae which were approximately half

the size of the seven basal serrae on the lateral margin. Subsequently

Poey (1876) described a second species, longirostris, from Cuba from

an adult male, 2,266 mm long, in which the upper tooth as illustrated

had equal-sized serrae on both margins, with eight serrae on the

medial margin and about seven on the lateral margin. In the same

account Poey noted that he had also obtained an adult female, 2,TlO

mm long, which he initially thought to be longirostris on external

features. However, examination of the teeth of this specimen led him

to the conclusion that it was not longirostris but probably signatus,

although he did not elaborate on the differences. Despite Poey's view

that signatus and longirostris were distinct, it is now clear that the

illustrations of the teeth of the holotypes could be encompassed by

changes that occur with growth (see Raschi et al. 1982), signatus

probably being based on a subadult and thus differing from the

longirostris adult. Furthermore, although it is over a century since

Poey described his two species, there is no subsequent evidence~o

support his belief that there are two species of Hypoprion off Cuba.

Cadenat's (1956) new species, bigelowi, from the tropical eastern

Atlantic can be relegated to the synonymy of signatus on the same

grounds that apply for longirostris. The holotype of bigelowi, an

adult of 1,6Tl mm, with basal serrae on both the medial and lateral

margins of the upper teeth, and with dermal denticles with five

longitudinal ridges and five posterior marginal teeth, was regarded

by Cadenat as distinct from signatus because the latter, as represented

by juvenile specimens in Bigelow and Schroeder (1948), was thought

to have basal serrae only on the lateral margins of the upper teeth,

and dermal denticles with only three ridges and three marginal teeth.

Detailed and extensive evidence establishing that these differences

are simply the opposite end points of the normal pattern of ontogenetic change in signatus is given in Raschi et al. (1982), who,

as a result, synonymise bigelowi with signatus, an action with which

I agree.

DESCRIPTION (see also Table 4).-Large sharks, growing to 2.55

m TL. Midline of back between dorsal fins with a low interdorsal

ridge. Upper precaudal pit strongly developed, lower pit weak.

Dermal denticles overlapping, subcircular to ovoid in outline,

slightly wider than long, each with three strong longitudinal ridges

and corresponding posterior marginal teeth in small specimens, but

with five ridges and teeth in adults.

Snout very long (8.5-10.3% TL), its tip sharply rounded. Anterior

margin of eye slightly forward of front of mouth. Nostrils strongly

oblique, with rather slitlike apertures, the anterior margin of each

with a narrow pointed lobe.

Dental formula 15-2-15/15-1-15 in two of five specimens counted,

15-2-15/14-1-14 in one, 15-2-16/15-1-15 in one, and 16-2-16/16-1-16 in

one. Upper teeth narrow, erect near the center of the mouth but increasingly oblique laterally, their lateral margins deeply notched,

their medial margins straight or slightly convex; distally both margins

smooth-edged, but basally there are large serrae which in small

specimens are confined to the lateral margin whereas in subadults

and adults they are present on both lateral and medial margins; the

number of serrae varies with size or age; in juveniles there may

be only two or three serrae laterally, whereas in two adult females

there are up to about five and nine medially, and two and six laterally,

and in one adult male there are up to about ten medially and eight

laterally; two small symphysial teeth. Lower teeth erect to slightly

oblique, with both margins deeply concave to notched, and smoothedged except for some slight basal irregularities particularly in larger

23

specimens; one small symphysial tooth.

First dorsal fin low, erect, its apex pointed, its rear tip of moderate

length (3.6-4.6% TL); origin of first dorsal varying from halfway

back along posterior (inner) pectoral margin to as far as posterior

(inner) pectoral corner. Second dorsal fin very low and long, and

slightly lower than the anal fin; length of second dorsal rear tip

2.0-2.3 (mean 2.2 in five specimens) times its height; origin of second dorsal ranging from above anal fin origin to about halfway along

anal base. Pectoral fin moderately short, weakly falcate, pointed

distally; origin of pectoral fin below or just anterior to fourth gill

opening; outer corner of pectoral when latter is adpressed to trunk

so that its anterior margin is horizontal reaches from at least fourfifths along first dorsal base to as far as first dorsal rear tip.

After preservation in alcohol, the color of the back and sides is

brownish grey while the underside is paler; in juveniles there are

no obvious black-tipped fins but the pectoral tip is dusky as are the

apical margins of both dorsal fins, the anal fin, and the upper caudal

lobe; in adults the only obviously dusky marking is on the underside of the pectoral fin which is increasingly darker towards its tip.

Vertebral counts as in Table 4. Counts of one other specimen

(USNM 1338Tl from Florida) are precaudal 104, caudal 80, and

a total count of 184. Centrum diameter considerably greater than

centrum length. Diplospondylous centra regular. Diplospondyly

begins about one-third along pelvic base. Length/diameter of

penultimate monospondylous centrum is 1.59 to 1.68 (mean 0.64

in three specimens), and length of penultimate monospondylous centrum/length of first diplospondylous centrum is 1.05 to 1.17 (mean

1.12 in three specimens).

The smallest free-living specimen I have seen was 930 mm- TL

while the largest embryo was 564 mm. Size at birth would appear

to be about 650 mm judging by Raschi et al.'s (1982) report of embryos up to 634 mm long and free-living (trawled) specimens as

small as 665 mm. Also, Applegate et al. (1979) illustrated a specimen,

presumably free-living, of 660 mm. There are no firm data on size

at first maturity in the male, except that Krefft5 notes that males

up to 1,560 mm were immature, whereas Cadenat and Blache (1981)

reported two adult males, 1,535 and 1,700 mm, with claspers extending 5.9 and 4.6% TL beyond the extremity of the pelvic fins

and hence presumably mature. Krumholz (1957) recorded a mature

male of 1,978 mm. Springer and Thompson (1957) reported adult

males of 2,007 and 2,159 mm. For females, Krefft (footnote 5) lists

immature specimens up to 1,450 mm, Daiber (1960) inferred that

one of 1,835 mm was immature since it had undeveloped gonads,

and Branstetter (1981) reported one of ca. 1,900 mm which "did

not appear to be mature." Contrasting with the last two specimens

was a pregnant female of 1,740 mm recorded by Poll (1951) and three

pregnant females of 1,776 to 1,790 mm reported by Cadenat and

Blache (1981). Raschi et al. (1982) noted a mature female of 1,900

mm. The number of embryos per litter ranges from 4 to 18 according to seven accounts in the literature. The smallest litter (four embryos from a 1,740-mm female) was reported by Poll (1951). Litters

of 10, 7, and 9 from females of 1,776, 1,790, and 1,790 mm, respectively, are recorded by Cadenat and Blache (1981), and two others

of 10 and 12 from females of 2,200 and 2,550 mm are documented

by Raschi et al. (1982). Bigelow and Schroeder (1948) also gave 12

as the litter size for signatus. Larger litters, 14 embryos in each,

were reported by Springer and Thompson (1957) and by Daiber

(1960) from females of 2,286 mm. Branstetter (1981) provided in-

'G. Krefft, Ichthyologie Seefischerei, Zoologisches lnstitut and Zoologisches Museum

der Universitiit Hamburg, Martin-Luther-King Platz 3, D-2000 Hamburg 13, West Germany, pers. commun. January 1980.
formation on a litter of 18. The maximum size to which signatus

grows was given by Manday (1968) as 3 m, although this may be

an estimate of potential size insofar as I have not discovered any

records of specimens of that length. Bigelow and Schroeder (1948)

stated that recorded specimens reach 2,766 mm (male) and 2,270

mm (female); they did not give the source of their data but I suspect

it was Poey (1876) in which case the 2,766 was an error of transcription for 2,266 which was the length of the holotype male of

longirostris. Ifthis is true, the only recorded male specimen to exceed 2,266 mm is one of 2,362 mm examined by S. Springer and

reported in Springer and Thompson (1957). Since female carcharhinids attain a larger size than males of the same species, it

is not surprising that the largest recorded female signatus is 2,550

mm (Raschi et al. 1982). The next smaller females are two of2,388

mm, slightly larger than the largest male, listed in Springer and

Thompson (1957).

DISTRIBUTION (see also Material Examined).-Both sides of the

tropical Atlantic, and extending significantly into temperate latitudes

both north and south in the western Atlantic. Specimens I have examined have had a much more limited distribution, from South

Carolina, Florida, and the Bahamas in the northwestern Atlantic,

and from about lat. l2°N (region of French Guinea and Portuguese

Guinea) and from off the Congo and northern Angola in the eastern

Atlantic.

Some of the accounts that further document and extend this

distribution include, for the western Atlantic, those of: Mather and

Gibbs (1957), who reported signatus from off Delaware at lat.

38°22'N, long. 69°35'W; Raschi et al. (1982), who noted that "recent records indicate that it is a common shark in the Florida Current and Gulf Stream, ranging as far north as the Middle Atlantic

Bight along the Outer Continental Shelf during the warmer months

of the year" and list many specimens supporting their statement;

Krumholz (1957), who recorded it from the Bahamas; Boschung

(1979) and Branstetter (1981), who each reported a specimen from

the southeast Gulf of Mexico; Springer and Thompson (1957), who

reported a specimen from the northern Gulf of Mexico off Mississippi; Applegate et al. (1979), who illustrated another from Veracruz

in the southern Gulf (Bahia de Campeche); Bigelow and Schroeder

(1948), who noted that signatus is abundant off the northern coast

of Cuba, from which island also the holotypes of signatus and

longirostris were described (Poey 1868, 1876) and from where

signatus has recently been reported (Manday 1968, 1975-latter account not seen); and Krefft (footnote 5), who informs me of 12

juveniles taken off southern Brazil and Uruguay (Jat. 33°-35°20'S,

long. 51 °20'-52°41' W). These accounts leave a considerable gap

in the western Atlantic distribution, with no records between the

northern Caribbean Sea and southern Brazil other than a doubtful

listing by Blosser (1909) from British Guiana.

For the eastern Atlantic coast, records by Cadenat (1956-holotype

of bigelowi) from about lat. 12°N, by Cadenat and Blache (1981-as

bigelowi) from Cap Vert (Senegal), Guinea, Ivory Coast, and

Dahomey, and by Raschi et al. (1982) for the Gulf of Guinea region

from lat. 4°14!6°09'N document the occurrence of signatus north

of the Equator, while those of Poll (1951) from lat. 5°5J!8°21'S cover

the south.

Although Raschi et al. (1982) summarized the depth distribution

of signatus as 200-600 m, "approaching the shallower end of this

depth range during hours of darkness," they also report captures

in the Florida Current at dawn in depths of <50 m and document

another five Anton Dohm stations off the east coast of the United

States where signatus was taken in depths from 135 to 175 m. Other

reports of shallow captures include those of Bigelow and Schroeder

(1948)-26 m off South Carolina; Poll (1951)-100 m off the Congo;

Boschung (1979)-near the surface in the southeast Gulf of Mexico; Branstetter (1981)-upper 80 m in the southeast Gulf of Mexico; and Krefft (footnote 5)-110 m in the southwestern Atlantic.

MATERIAL EXAMINED.-IRSN 8.458, four embryos, two males,

320 mm, and two females, 340 mm, Angola, 7°16'S, 12°08'E, I

October 1948, M'Bizi; USNM 133827, male embryo, 457 mm,

Florida, Key West, off Cosgrove Reef, April 1947, S. Springer;

USNM 197373, male embryo, 564 mm, West Atlantic, Oregon;

USNM 38508, female, 930 mm, North West Atlantic, 33°37'30"N,

77°36'30"W, 20 October 1885, Albatross; MRAC 80256, female,

998 mm, East Atlantic, 5°53'30"S, U040'30"E, 21 August 1948;

MNHN 55-4915, female, 1,590 mm (holotype of Hypoprion

bigelowi), within the region of the coasts of French Guinea and Portuguese Guinea, 8-10 March 1955; USNM 196131, female, 1,740 mm,

North West Atlantic, 29°46'N, 80 0

12'W, 30 April 1961, Silver Bay.

Also IRSN 8.397, uterus with four embryos, 325 to 340 mm,

Angola, 7°16'S, l2°08'E, 1 October 1948, M'Bizi; MRAC 8.452,

head and tail of specimen from Angola, 8°21'S, 12°46'E, 8 February

1949, M'Bizi; MRAC 8.451, head of specimen from Angola, 7°16'S,

12°08'E, 1 October 1948, M'Bizi; IRSN 8.459, jaws of specimen

from South Atlantic, 1948-49, M'Bizi; UMMZ -, jaws of specimen

2,170 mm, Florida, the Hump off Islamorada, 24 June 1961, H.

Brown; USNM 112582, jaws of adult male, 2,286 mm, Bahamas,

Bimini, 3 June 1948, S. Springer.

ACKNOWLEDGMENTS

I am grateful for the willing assistance given to me by the staff

of those museums which provided material and which I list under

that heading. V. G. Springer kindly assisted with literature and gave

valuable advice on the manuscript. I would also thank L. 1. V. Compagno for information, advice, and discussion throughout the course

of this study.

The drawings of shark teeth are by Peter A. McCrery. The final

24

typing of the manuscript was by Norma Knuckey.

Financial support for this study was provided by contracts between the Smithsonian Institution and the Atomic Energy Commission (AEC [30-1]2409) and the Office of Naval Research (NONR

1354 [09]) and by grants from the National Science Foundation

(GB-245) and the Internal Research Fund, Victoria University of

Wellington.
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