THE UNIVERSITY

OF ILLINOIS

LIBRARY

Return this book on or before the
Latest Date stamped below. A
charge is made on all overdue
books.

U. of I. Library

17625-S

**>* OF IIUWIS IBs,
FIELD MUSEUM OF NATURAL HISTORY.

PUBLICATION 198.
ZOOLOGICAL SERIES. VOL. XII, No. 2.

NOTES ON FISHES FROM THE
ATHI RIVER IN BRITISH EAST AFRICA.

BY

CARL L. HUBBS,

Assistant Curator, Division of Ichthyology
and Herpetology.

CHARLES B. CORY,
Curator, Department of Zoology.

CHICAGO, U. S. A.
January, 1918.

NOTES ON FISHES FROM THE ATHI RIVER IN
BRITISH EAST AFRICA

BY CARL L. HUBBS

A small collection of fishes was obtained in the Athi River by the
Museum's East African Expedition of 1905-7. Among them three
species of Barbus cannot be identified with any of the known forms and
are described as new. These "Athi River fishes were all collected at
one time and place, at low water (dry season) in pools at a point about
25 miles S. E. of Nairobi, and perhaps 10 miles from the Uganda Rail-
way (north). They were taken, with a small seine, about November,"

I905.1

In addition to these fishes an adult eel (Anguilla bengalensis) "was
taken on a hook and line in the Tana River about 35 miles S. E. of
the summit of Mt. Kenia." 1

Labeo cylindricus Peters.

Boulenger, Cat. Fresh-water Fishes Africa, 1, 1909, pp. 331-333,
text fig.

Our 32 specimens (Cat. No. 6107), varying in length from 29 to 97
mm., agree in their characters with Tylognathus montanus Gunther,
which Boulenger considers to be based upon half grown specimens of
L. cylindricus. At this stage the species in all details closely resembles
the adult of Labeo victorianus. In our largest specimen, however, the
differential growth of the head has already proceeded in the direction
of the peculiar adult physiognomy: the eye is inserted superolaterally,
is located a little behind the middle of the head, and is decreased in
proportionate size, being contained 6.0 times in the head; the production
of the antorbital portion of the face is already in process, the suborbital
having become wider than the orbit, but still remaining narrower than
the interspace between the eye and the upper angle of the branchial
aperture.

Scales in 5^, 6, or 6>£ rows above the line, and in 6>£ or 7^ rows
between the lateral line series and the midabdominal line. The varia-

1 Quoted from letter by Carl E. Akeley, who had charge of the expedition.

9

io FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

tion in the number of scales along the lateral line, including those on the
base of the caudal rays, is expressed in the following tabulation:

Scales

36

VJ

18

Specimens (both sides counted)

5

IQ

II

Barbus athi sp. nov.

Plate I

Type specimen, a mature male 152 mm. long to end of last vertebra,
Cat. No. 6108, Field Museum of Natural History. The description is
based upon the type and io paratypes (Cat. No. 6109), which vary in
length from 105 to 132 mm. Fifty-five other specimens, ranging in
length from 21 to 103 mm., were secured (Cat. No. 6 no).

This species is a member of the B. hindii group.

From hindii, which is recorded by Boulenger from the Athi River,
it differs in the less robust form of the body, but deeper caudal peduncle,
in the much shorter dorsal spine, and from the type in the lower num-
ber of scales along the lateral line.

Our species is probably most closely related to Barbus krapfi
Boulenger,1 from the type description of which it differs in the shorter
pectoral fins (much shorter than the head), in the longer head, with
shorter and blunter snout, and in the shorter barbels; the head is con-
tained 3.2 to 3.3 times in the length, rather than from 3^ to 34/s times;
the snout is contained 3.1 to 3.35 times in the head, instead of from
3/4 to 3^ times; the posterior barbel at most is x/6 longer than the eye
(iX to i >^ times eye in krapfi}, and the anterior barbel is usually shorter,
at most barely equal to, the diameter of the eye (i to i>^ times eye in
krapfi}. As the type specimen is mature, and as the eye has attained the
small relative size given by Boulenger for the adult of krapfi, we are
unable to attribute these differences to age-variation. It is probable
that the specimens which Boulenger records from the Limba River, a
tributary of the Athi, as the young of his krapfi, are referable to B. athi.

Barbus ahlselli Lonnberg2 is another closely related species; it differs,
however, in its more slender form, larger eye, narrower interorbital,
and higher dorsal.

Barbus mawambiensis Steindachner,3 a West African species of the
same group, has a relatively deeper caudal peduncle and higher dorsal.

1 Cat. Fresh- water Fishes Africa, 2, 1911, p. 54, text fig.
1 Kungl. Sv. Vet. Akad. Hand., 47, 6, 1911, p. 39.
* Denkschr. Akad. Wiss.JWien, 89, 1913, p. 25.

JAN., 1918. FISHES FROM THE Arm RIVER — HUBBS. n

Depth of body, 3.1 (3.0 to 3.35)* in length of base of caudal; length
of caudal peduncle, from anal base to end of last vertebra, 1.4 (1.3 to
1.5) times its depth. Extreme length of head 3.3 (3.2 to 3.3); snout,
3.2 (3.1 to 3-35)1; eye, 5.3 (4.4 to 5.7); bony interorbital width, 3.35
(3.5 to 3.7); upper jaw extending to between verticals from posterior
nostril and eye, its length 3.4 (3.25 to 3.5) in head; lips well developed,
the lower continuous across the chin, where it is produced slightly
backward as a rounded lobe as long as the pupil. Anterior barbel
usually shorter the eye (0.9 eye in type), at most barely as long as the
eye; posterior barbel 5/6 as long as the eye in the type (shorter in some
paratypes, at most l/6 longer than the eye).

Scales sculptured with fine cross-set longitudinal striae; scale-rows
in type: 26 on the left side, 24 on the right side, along the lateral line
(including 2 on the base of the caudal rays) ; 4^2 below, and 4^ above,
lateral line; 2 between lateral line and the pelvic fin; 12 around caudal
peduncle.

Table showing variation in number of scales along lateral line:

Scales

21

24.

25

26

27

Specimens (both sides)

A

17

18

M

6

The distance from the origin of the falcate dorsal to the occiput is
equal to the distance from the end of the dorsal base to the upper free
base of the caudal, or one orbital length beyond. Dorsal rays, 3 simple
plus 9 (20 specimens), or 8 (2), branched rays; the third simple ray is
articulate along its front edge and on its soft tip, but greatly strength-
ened posteriorly by the deposition of bone, in which the articulations
are mostly obsolescent; this third ray is grooved behind to receive the
first branched ray when the fin is depressed; its posterior edges are
smooth and even; the length of the bony portion of the ray is contained
1.6 (1.3 to 1.6) times in the head, reaching its proportionate maximum
in specimens about 80 mm. long, in which the ray is contained from
1.2 to 1.4 times in the head. Anal rays, 3 simple and 5 divided; the
longest, when depressed, reaching the base of the lowermost caudal
rays. The pectoral reaches to, slightly beyond, or not quite to, the
vertical from the insertion of the pelvic fin; its length is contained 1.3
(1.3 to 1.4) times in the head ("pectoral as long or slightly shorter
than the head" in B. krapfi, "not reaching ventral"). The base of the
pelvic fin lies below the origin of the dorsal.

1 Measurements given of the ten paratypes, smaller in smaller specimens.

12 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

Color in alcohol grading from deep purplish brown along the mid-
dorsal line to yellowish white below; the scales on the back and upper
sides become abruptly darker basad; a number of black spots usually
present along the upper sides; the head is dark above, on the opercle,
and below the eye. Paired fins clear; median fins dusky on their inter-
radial membranes.

(athi, named for the Athi River, in which the types were collected.)

Barbus helleri sp. nov.

Plate II

Type specimen, a mature female 51.5 mm. long to the caudal base,
Cat. No. 6105. The type description is supplemented by measurements
of 10 paratypes, mature males and females varying in length from 48 to
51 mm. (Cat. No. 6114). Ninety-two other specimens were examined,
26 to 48 mm. in length (Cat. No. 6115).

Barbus helleri is closely related to Barbus longicauda of the Zambesi
River (recorded by Boulenger from the Nairobi River, a tributary of the
Athi), and to B. thikensis of the Tana system (recorded also from Lake
Victoria) . From longicauda,1 helleri is distinguishable by its pronounced
lateral band coloration, by the shorter pectoral fin, and by the much
lower dorsal spine, which is constantly shorter than the postrostral
length of the head ("as long as or a little shorter than head" in longi-
cauda). From thikensis, helleri differs in the narrower interorbital,
lower dorsal spine, smaller scales, and apparently in the more distinct
lateral band, and in the constant presence of the caudal spot. B.
amphigramma is another similar species, but has a smooth dorsal
spine.

Depth of body, 3.9 (3.6 to 4.1) in length to caudal base; length of
caudal peduncle, from anal base to end of last vertebra, 2.1 (1.75 to 2. 2)
times its least depth. Extreme length of head 3.75 (3.45 to 3.85) ; snout
in head, 4.0 (4.0 to 4.2); eye, 4.0 (4.0 to 4.2); least interorbital width,
3.0 (2.9 to 3.6); upper jaw extending to vertical from front of orbit,
being about as long as the snout, and about as long as the width of the
terminal or subinferior mouth; lips not conspicuously developed, the
lower with a frenum. Anterior barbel as long as the pupil, or shorter;
posterior barbel as long as eye, rarely a little longer, often only two-
thirds as long as eye.

1 The specimens recorded under this name by Gilchrist and Thompson (Ann. S.
Afr. Mus., II, 1913, p. 407) do not agree with the descriptions of this species, and
probably represent another species. From these specimens B. helleri is apparently
distinguished by the more robust body; smaller eye; in having usually 4 scales from
the lateral line to the ventral, and usually 16 around the caudal peduncle; and in the
coloration.

JAN., 1918. FISHES FROM THE ATHI RIVER — HUBBS. 13

In the type there are 35 radially striate scales along the lateral line;
from the lateral line series there are 7^ rows to the middorsal line, 6^
rows to the midventral line and 4 rows to the insertion of the pelvic fin;

there are 16 series around the caudal peduncle. The variation in the

6>£— 7#
paratypes is expressed in the formula: 34 to 36, ^-^ 3 (rarely) to

4, 14 (rarely) to 16.

The dorsal fin is slightly falcate; its origin is equidistant from the
end of the snout (or from the front of orbit), and from the end of the
lateral line; the dorsal fin has 7 branched rays; the last of the simple
rays is strong and serrated; its bony length is constantly a little shorter
than the postrostral length of the head. Anal with 5 branched rays, the
longest of which is a little lower than the dorsal spine, and fails by much
to reach the caudal fin. The pectoral fin falls short of the pelvic insertion,
its length being contained 1.7 (1.45 to 1.65) times in the head. The
pelvic extends from a little before the vertical from the dorsal origin
almost or quite to the anus.

The color in alcohol is brownish above, darkest towards the base of
the scales; grading to silvery below the middle of the sides on the head
and body. The axial septum of the lateral muscles is marked by an
intense black streak, which gracefully curves upward above the lateral
line anteriorly, and becomes faint towards the head; posteriorly a dark
area diffuses outward from the black streak, forming thus a lateral band;
the lateral line is more or less blackish; a black spot is always present at
the caudal base. The dorsal, caudal, and pectoral fins are light dusky,
while the anal and pelvic fins are clear. In the young the black streak
is a little wider, but there are no important individual nor age variations
in the coloration.

(helleri, named for the naturalist Edmund Heller, who accompanied
the East African Expedition.)

Barbus akeleyi sp. nov.

Plate III

Type specimen, a female with mature eggs, 74 mm. long to caudal
base, Cat. No. 6106, Field Museum of Natural History. The description
of the type is supplemented by measurements of 12 paratypes (Cat.
No. 6m), varying in length from 58 to 71 mm.; 48 other specimens
(Cat. No. 6112), from 27 to 59 mm. long, were secured.

Barbus akeleyi is a member of a rather large group of closely related
species inhabiting the southeastern waters of Africa. A brief comparison
has been prepared to indicate the major characters in which B. akeleyi
differs from the descriptions of its closest allies. It differs from serrifer

14 FIELD MUSEUM or NATURAL HISTORY — ZOOLOGY, VOL. XII.

in the longer snout and eye, shorter barbels, and in the shorter pectoral
and more falcate dorsal with lower spine; from luazomelas Lonnberg,
in the deeper body, longer head, shorter posterior barbel, higher dorsal
spine; from lumiensis in the longer and narrower head, longer snout and
eye, shorter posterior barbel, lower dorsal spine, shorter pectoral, and
more robust caudal peduncle; from loveridgii in the longer head, smaller
eye, in the shorter pectoral, and in the falcate and lower dorsal; from
minchini in the smaller eye, longer barbels, lower and more falcate
dorsal, shorter pectoral, etc.; from laticeps in the narrower head, smaller
eye, lower dorsal, and more robust body; from sexradiatus in the nar-
rower interorbital, shorter pectoral, and in the number (7) of branched
rays in the dorsal fin; from salmo in the narrower interorbital, lower
dorsal spine, and in the position of the pelvic fin base below the origin
of the dorsal; from kerstenii in the smaller eye, shorter pectoral, and
more falcate dorsal; from entaenia in the same characters and in colora-
tion; from neumayeri in the fewer scales along and above the lateral
line, in the smaller head and in the more anterior insertion of the pelvic
fin in reference to the dorsal; from nairobiensis (from the Athi basin)
in the narrower interorbital, shorter barbels, in the insertion of the pelvic
fin before the origin of the dorsal, and in the fewer scales (26 to 28,
rarely 25 or 29, instead of 28 to 30); from percivali in the smaller eye,
narrower interorbital, lower dorsal spine, and in coloration (see note in
description of coloration of the young of B. akeleyi} ; from zanzibaricus
in the much smaller eye, narrower interorbital, in the larger scales and
in the insertion of the pelvic fin; from argentatus in the smaller eye, fewer
dorsal rays, in the lower dorsal, fewer scales, etc.

Depth of body, 3.35 (3.0 to 3.35) in length to base of caudal; length
of caudal peduncle from anal base to end of last vertebra, 1.6 (1.5 to 1.8)
times its least depth. Extreme length of head, 3.4 (3.2 to 3.5); snout
in head, 3.4 (3.4 to 3.8); eye, 5.2 (4.2 to 4.7); least interorbital width,
3.2 (2.8 to 3.2); upper jaw extending to about the vertical from the
front margin of the orbit, its length 3.4 (3.2 to 3.6) in head; width of
terminal mouth, 3.6 (3.2 to 4.0); lips well developed posteriorly, inter-
rupted at the chin, anterior barbel as long as eye, ranging to one-third
longer; posterior barbel 1.7 (1.5 to 1.8) times eye.

4/^
Scales radially striate, 26 to 28 (rarely 25 or 29) .^ to ^ 3 between

lateraVline and ventral, 12 round caudal peduncle.

Scales along lateral line

25

26

27

28

2Q

Specimens (both sides counted)

2

17

26

17

2

JAN., 1918. FISHES FROM THE ATHI RIVER — HUBBS. 15

The dorsal fin is evidently but not strongly falcate; its origin is
equidistant from the end of the last vertebra and from the middle of
the snout; the origin is directly over the middle of the pelvic base.
Dorsal with 7 branched rays (only i among 45 specimens counted has
8 rays); there are 3 simple rays; the first very short, sometimes con-
cealed, the second short and slender, the third strong and bony, except
at its tip; the posterior edge on each side is armed with numerous ser-
rations; the front edge of spine is closely articulate, while the bony por-
tion is more sparsely and less distinctly articulate; the bony portion of
the spine is contained 1.4 (1.25 to 1.4) times in the head. The anal fin
is composed of 3 simple and 5 branched rays (2 specimens among 45
have 6 rays); the fin has a straight margin, and when depressed falls
far short of the caudal; the pectoral fin fails to reach the pelvic, being
contained but 1.4 (1.35 to 1.6) times in the head; the pelvic fins reach
almost to the anus.

The coloration in alcohol is brown above and silvery below; with a
dark mediodorsal streak; a rather diffuse lateral band posteriorly, in-
tensified to form a blackish line near its lower border; a dark purplish
brown blotch along the region of the lateral line anteriorly, the color
becoming darkest near the base of the scales; a distinct caudal spot
about as large as the pupil. The top of the head and the opercle are
dark. Caudal fin dusky; dorsal with a little pigment; other fins clear.

In a few very young specimens the pigment along the lateral band is
concentrated more or less definitely into three spots; one above the
pectoral, another above the anal origin, and the third at the caudal base.
This color type, rarely developed in the young of akeleyi, is the typical
adult color developed in the related B. percivali, and still more notably
in other species such as B. trispilus.

Chiloglanis deckenii Peters.

One specimen, 50 mm. long to the caudal base (Cat. No. 6113),
agrees in nearly every detail with the descriptions of this species. One
difference between our specimen and Peters' figure cannot, however,
be overlooked, namely the form and length of the lower labial barbels;
in this respect the specimen at hand agrees closely with the type figure
of Synodontis eurystomus Pfeffer,1 which Boulenger regards as a synonym
of C. deckenii. The maxillary barbel is flattened and slightly fringed
along both sides. Greatest depth of body, 6.0 in length without caudal;
length of caudal peduncle, from end of anal base to end of last vertebra,
1.75 times its least depth. Extreme length of head, 3.3 ; diameter of eye,
6.0 in head; eye in interorbital, 1.5; interspace between posterior nostril

1 Jahrb. Hamb. Wiss. Anst., 10, 1892 (1893), p. 159, pi. 1, fig. 5a, b.

16 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

and eye, i.i in interorbital width. Dorsal I, 5 ; base of adipose dorsal, 1.9
in interdorsal space; anal with 3 simple and 7 branched rays, its basal
length a little shorter than either the height of the anal or the length of
the adipose fin; pectoral spine in head, 1.4 (left side) or 1.6 (right) ; pelvic
fin extending a little beyond the anal origin, its length, 2.35; caudal fin
deeply forked, the upper lobe (measured from base of developed rays)
1.2 in the lower lobe, which is contained 1.2 times in the head. Colora-
tion as described and figured for C, deckenii.

Tilapia athiensis Boulenger.

Tilapia nilotica athiensis Boulenger, Proc. Zool. Soc. London, 1916,

P- 345-

Dr. Boulenger recently presented an interesting account of the
variation, among Cichlids, of the number of spines in the anal fin. He
described, as Tilapia nilotica athiensis, certain specimens from the Athi
River system, which differ from Tilapia nilotica only in the constantly
increased number of anal spines (4 or 5 instead of 3) . While accepting
Boulenger's general conclusions, we consider that the Athi form should
be given full specific status. A single genetic character, constant in all
or in the large majority of each of two non-intergrading forms, is re-
garded by us as sufficient grounds for specific distinction.

•" a

^j E

UNIVERSITY OF ILLINOIS-URBANA