International Journal of Aquaculture, 2015, Vol.5, No.5 1
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and adipose fins; and the black-edge of the forked
caudal fin of
H. vittatus
; the reddish-orange lower
edge of the caudal fin and the anterior area of anal fin
of
H. brevis
. Given that the morphological, biochemical
and molecular data are only complementary and not in
competition with one another (Chang, 2004; Mohamed,
2010), morphological phylogeny analysis should be
compared, contrasted and combined with the analysis
of the molecular phylogeny, to more clearly defined
taxonomic status of the three species
H. vittatus
,
H.
brevis
and
H. forskalii
in the Nile waters from different
regions in Sudan.
The three species are very similar in size, the
maximum length in each case being a little less than
500 mm The distinctive features are given in (Table 6).
A detailed description of each species, based on the
present study, is also provided below.
Table 6 A summary of distinctive features of
H. forskalii
;
H. lineatus
and
H. brevis
Characters
H. forskalii
H. lineatus
H. brevis
Depth of body into length
Usually more than 4½
Less than 4½
3-4
Length of head into length of body 4-5
3-4
Less than 4½
Caudal peduncle: depth into length Not less than 1.7
Not more than 1.7
Not more than 1.7
Position of first ray of dorsal fin
Distinctly in advance of
pelvic fin
Above or slightly in advance of
pelvic fin
Directly above pelvic fin
Lateral line scales
48-54(7½ - 8½/3½ - 4½)
44-48(7½ - 8½/3½ -4½)
47-54(8½ - 9½ /5½)
Scale between lateral line and scaly
process at base of pelvic fin
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Hydrocynus vittatus
(Castelnau, 1861)
Synonyms:
Hydrocinus vittatus
Castelnau, 1861
Hydrocyon lineatus
Bleeker, 1862
Gunther, 1864
Hydrocyon vittatus
Boulenger, 1898
Description:
A brilliant silvery-coloured fish, with
compressed elongated body, 205 to 375 mm standard
length, covered by ctenoid scales and each scale
marked by a dark spot forming parallel bands visible
above the lateral line, and a very small adipose fin
behind the dorsal fin. Edges of dorsal
and adipose fins
black, forked edge of caudal fin distinctly black.
Position of the dorsal fin distinctly before the insertion
of ventral fin. Eye diameter 80% of inter-orbital width.
Measurements are in %SL:
Body Depth 20.4 to 28.9;
Head length 23.1 to 27.5; head width 11.2 to 13.1;
upper snout length 9 to 11.2; lower snout length 10 to
13.7; eye diameter 6.6 to 9.2; inter-orbital width 9.7 to
11.6; post-orbital length 10.8 to 14.6; dorsal-to-
adipose fin 27.7 to 37.5; pre-dorsal length 46.4 to 61.6;
pre-ventral length 50.8 to 65.3; caudal peduncle length
10.9 to 12.6; caudal peduncle depth 9 to 11.8.
Measurements are in %HL:
Head width 44.7 to 54.1;
upper snout length 37.6 to 45.4; lower snout length
40.4 to 55; eye diameter 28.8 to 37.1; inter-orbital
width 39 to 46.6; post-orbital length 43.6 to 58.7.
Lateral line scales 47-58; Dorsal fin rays 8 -10;
pectoral fin 12 -16; ventral fin 9 - 10; anal fin 12 - 16;
gill rakers 11-16; teeth in upper jaw 11-14; teeth in
lower jaw 10-14.
Hydrocyon brevis
(Günther, 1864)
Synonyms:
Hydrocynus forskalii
Cuvier & Valenciennes, 1849
1864
Description:
A brilliant silvery-coloured fish, with
compressed short body, 185 to 256 mm standard
length, covered by ctenoid scales and each scale
marked by a dark spot forming parallel bands visible
above the lateral line, and a very small adipose fin
behind the dorsal fin. Fins of
H. brevis
are grey, but
the lower caudal-fin lobe and the anterior area of anal
fin are tinged with reddish-orange. Position of the
dorsal fin slightly back the insertion of ventral fin.
Eye diameter 77% of inter-orbital width.
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