International Journal of Aquaculture, 2015, Vol.5, No.5, 1
-
9
Research Report Open Access
Taxonomic Revision of the Tiger Fish
Hydrocynus vittatus
(Castelnau, 1861),
H.
Brevis
(Cuvier & Valencience, 1849) and
(Cuvier, 1819) from the Nile
in Sudan
Elagba H.A. Mohamed , Wigdan A.S. Al-Awadi
Natural History Museum, Faculty of Science, University of Khartoum, Sudan
Corresponding author Email:
International Journal of Aquaculture, 2015, Vol.5, No.5 doi: 10.5376/ija.2015.05.0005
Received: 06 Feb, 2015
Accepted: 08 Mar, 2015
Published: 06 May., 2015
Copyright © 2015
Mohamed and Al-Awadi, This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
:
Mohamed and Al-Awadi, 2015, Taxonomic Revision of the Tiger Fish Hydrocynus Vittatus (Castelnau, 1861),
H. Brevis
(Cuvier & Valencience, 1849) and
H.
Forskalii
(Cuvier, 1819) from the Nile in Sudan, International Journal of Aquaculture, Vol.5, No.5: 1-9 (doi: 10.5376/ija.2015.05.0005)
Abstract
The main objective of this study was to revise the taxonomic status of three species from the
Hydrocynus
:
(Castelnau, 1861)
Cuvier & Valencience, 1849) an
(Cuvier, 1819), commonly known as "Tigerfish" to
determine the morphological characters for distinguishing them. The study was based on morphometric and meristic characters plus
body weight of specimens. Analysis of morphological characters was done by the statistical programme “PAST”. The study also
considered the length – weight relationships and the type of growth for each species. Twenty morphometric characters had almost
equal loads, ranging between (-0.1843 and -0.2436) in separating the three species. The number of lateral line scales, LLS, had the
biggest load of (-0.9994) followed by the number of teeth in upper jaw, UJT (-0.5643), the pectoral fin rays, PFR (-0.4638), gill
rakers, GR (-0.4596) and the number of teeth in lower jaw, LJT (0.3471). The morphological results indicated that a combination of
morphological characters can be used to separate the three species of the genus
Hydrocynus
. They may also be distinguished by the
position of the dorsal fin compared to insertion of the ventral; the black-edge of the dorsal
and adipose fins and the black-edge fork
caudal fin of
H. vittatus
; and the reddish-orange lower caudal-fin lobe and the red anterior area of anal fin
of H. brevis
. The
length-weight relationship was W =
3.088
L
-2.079
for
H. vittatus
and (r
2
= 0.923); W =
3.451
L
-2.534
for
H. brevis
and (r
2
= 0.664); W =
2.9981L
-1.9815
and (r
2
= 0.418) for
H. forskalii
. The values (
b
= -2.079, -2.534 and --1.9815) indicated allometric growth of the three
species. There was a strong positive correlation between standard body length and body weight of
H. vittatus
. It is recommended that
morphological analysis should be compared and combined with biochemical and molecular phylogenetics.
Keywords
Hydrocynus
,
H. vittatus
,
H. brevis
and
H. forskalii
, Length-weight Relationship, Morphology, Taxonomy.
1. Introduction
Hydrocynus
is a
of large
in the
famil
that contains five species (Boulenger,
1907), with three species common in the Nile (Sandon,
1950). These are namely
Castelnau, 1861),
(Cuvier & Valencience, 1849) and
(Cuvier, 1819). The three species share similar
common names "Tiger-fish, Kas and Kalb elbahr" by the
native fishers in Sudan and share similar distribution in
the White Nile, Blue Nile and the Nile to Lake Nubia,
bu
s the commonest species (Bailey, 1994).
Lik
is deep bodied with dark spot
on the adipose fin (Bailey, 1994).
s
easily distinguished from
y shorter body
covered with smaller scales and small eyes, but the two
species are not distinguished under special names by
the native fishermen (Sandon, 1950). The synonymy of
with
was revised by Brewster
(1986). However, all of them are rather similar in
appearance, their distinction requiring careful
examination.
Therefore, the present study was designed to revise
and compare the morphological characteristics of the
three species by using a combination of both
morphometric and meristic characters. It is an attempt
to taxonomically characterize each species in the Nile
waters of Sudan, and determine the morphological
characteristics that contribute mostly to the variation
of the three species. Analysis based on measurement
of morphological characters was done using the
Paleontology Statistical program “PAST”. This is a
software package originally aimed at Paleontology but
currently has become popular in taxonomy, ecology
and other fields (Hammer et al., 2001). It is a tool
highly recommended for determining the relationships
between species and populations of a species (Thorpe,
1987; Mwanja et al., 2011; Mohamed, 2014; Mohamed
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