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International Journal of Marine Science 2013, Vol.3, No.21, 166-172
http://ijms.sophiapublisher.com
168
Specimens were identified according to Bruce (1987),
Kensley and Schotte (1989) and Trilles et al. (1989). In
addition, some specimens were sent for identification
to Prof. Dr. N. L. Bruce of the University of Copenhagen
and Prof. Dr. S. Ravichandran of the Annamalai
University, India.
3 Results
3.1 Inventory of parasites collected
A total of 680 fish specimens belonging to 10 families
and 31 fish species were examined. Among these
fishes, only four species were infected with three
species of isopods. The infected fishes were:
Chelon
macrolepis
(Smith, 1846),
Liza aurata
(Risso, 1810)
and
Moolgarda seheli
(Forsskål, 1775) of the family
Mugilidae as well as
Lutjanus gibbus
(Forsskål, 1775)
of the family Lutjanidae. The detected isopods were:
Nerocila orbignyi
(Guérin-Méneville, 1832),
Cymothoa
exigua
Schioedte and Meinert, 1884 and
Ceratothoa
capri
(Trilles, 1964).
Detailed information on these
isopods and their particular hosts together with the
site of infection and the infection rate for each
isopod species will be shown in the subheadings
(3.3-3.5).
3.2 Taxonomy of isopod species
Inspection of the collected fishes revealed the
occurrence of three isopod species. These are
Nerocila
orbignyi
,
Cymothoa exigua
and
Ceratothoa capri
.
According to WoRMS (2013), all these parasites
belong to the family Cymothoidae, superfamily
Cymothooidea, suborder Cymothoida, order Isopoda,
superorder Peracarida, subclass Malacostraca and
subphylum Crustacea of the phylumArthropoda.
The following is a brief account on the site and rate of
infection of the fish hosts from the Red Sea with these
isopods, description and synonyms of concerned
parasites as well as the geographical distribution of the
known hosts for such parasites in the world.
3.3
Nerocila orbignyi
(Guérin-Méneville, 1832)
Materials examined: Two female specimens of
N.
orbignyi
were found attached to the base of the
pectoral fin of two mugilid fishes; one (out of 24)
specimen of
Moolgarda seheli
and one (out of 13)
specimen of
Liza aurata
. So, the infection rate of these
two fishes with
N. orbignyi
was 4.2% and 7.7%,
respectively. Length of the infected fishes was 24.8
cm and 26.5 cm, respectively and their weight was
105 gm and 150 gm, respectively.
Description: Based on two specimens. Body size of
the parasite 10.5-11.5 (11.0) mm long and 5.0-5.4 (5.2)
mm wide. Cephalon anterior margin within distinct
medial point; eyes small. Pereonites 1-4 posterolateral
angles not produced; pereonites 5-7 posterolateral
angles produced, acute. Pleonite 1 longest ventrolateral
margins of pleonites 1 and 2 posteriorly directed,
extending to, or beyond pleonite 5; pleonites 3-5
lateral margins weakly produced, narrowly rounded.
Pleotelson lateral margins angled, then converging to
caudomedial point. Antennule articles 1 and 2 partly
fused; antenna with 11 articles. Pereopod dactyli
without nodules. Pleopod 2 appendix masculina about
0.5 length of endopod; pleopod 5 endopod with 2 large
folds. Uropod exopod curving medially; endopod
straight, distal margin obliquely truncate, with
distomedial point (Figure 1 and Figure 2).
Figure 1 A:
Nerocila orbignyi
attached to the base of the
pectoral fin of
Moolgarda seheli
. B:
Nerocila orbignyi
, dorsal
view
Figure 2 Camera Lucida drawings of
Nerocila orbignyi
from
the Red Sea, Yemen coast