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Vol. 54, 2015
Cymothoa frontalis, a cymothoid isopod parasitizing the belonid fish Strongylura strongylura from the Malabar Coast (Kerala, India): redescription, description, prevalence and life cycle
Aneesh Panakkool Thamban1, Sudha Kappalli1*, Helna Ameri Kottarathil1, Anilkumar Gopinathan2 and Trilles Jean Paul3
1Post Graduate Department of Zoology and Research Centre, Sree Narayana College, Kannur 670 007, India
2School of Biosciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India
3UMR 5119 (CNRS-UM2-IRD-UM1-IFREMER), Equipe
Adaptation Ecophysiologique et Ontogenèse, University of Montpellier 2,
CC. 092, 34095 Montpellier, Cedex 05, France
Abstract
Background: Cymothoa frontalis
Milne Edward, 1840 is a very poorly described cymothoid,
notwithstanding the previous redescription of the female. Pertinently,
to date, the host of C. frontalis
has not been identified with adequate precision. Most of the
descriptions of cymothoids carried out hitherto were based primarily on
females, but practically ignoring other life cycle stages. The present
paper redescribes the female and describes other life cycle stages of
the species C. frontalis to get better precision in their identification.
Results: The female phase of C. frontalis
is redescribed according to type specimens extant in the NMNH, Paris,
and also by the data obtained from live specimens collected during the
present study. The general morphology and appendages of various life
cycle stages of the species are described. Among 80 fish species from
35 families examined, C. frontalis
was recovered only from Strongylura strongylura signifying its
oligoxenous host specificity, the prevalence and intensity being 68.65%
and 1.9, respectively. Each host fish in more than 85% of the
population was infested with a pair of C. frontalis, in three combinations, predominantly with male-female pair (70.9%). C. frontalis
exhibited strict site specificity attaching to the buccal cavity of the
host fish. The study has also identified three major phases (marsupial,
free living and infective) in the life cycle of C. frontalis.
The zygotic-staged marsupiumites were developed through five sequential
ontogenetic stages. The manca released from the marsupium become
infective after a brief period of free swimming life. During the
infective phase, C. frontalis
completes remaining life cycle stages with successive moulting.
Further, six successive stages of the ovigerous females have also been
identified.
Conclusions: The present redescription of the female and the description of transitional, male, juvenile and larvae of C. frontalis facilitate
precise identification of the species at any stage of the life cycle.
Further, the strict host and site specificities of the parasite, as
borne out from the present study, and its high degree of prevalence in
the host make C. frontalis as an ideal model organism to study the strategies to be adopted for the management of parasites infesting edible fishes.
Key words: Cymothoa frontalis; Cymothoidae; Redescription; Description; Prevalence; Life cycle; Strongylura.
*Correspondence: E-mail: pdellape@fcnym.unlp.edu.ar
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