Abstract
Cymothoid isopods of the genus Nerocila are generally poorly known. The aim of this work was to document the first record of cymothoid isopod Nerocila exocoeti for the South-West Indian Ocean, representing a significant westward range extension for this species. A single adult, female N. exocoeti and 38 mancae specimens were collected from a live sharksucker Echeneis naucrates at D'Arros Island, Seychelles. The female isopod specimen was examined using a stereo microscope and described based on distinct morphological traits. Observations of novel behaviour were also made for E. naucrates. The examined female isopod specimen measured 26mm long by 10mm wide. It possessed short coxae with the postero-lateral angles of pereonites 1-5 not produced and those of 6 and 7 reduced. The first antenna was composed of eight articles and the endopod of the uropod was half the length of the exopod. These traits confirm the specimen as N. exocoeti. Observations of novel behaviour in the wild host specimen showed the individual to deliberately and repeatedly swim ashore before thrashing in the substrate, returning to the water only once the isopod was removed. To date, N. exocoeti is known from India, Indonesia, Papua New Guinea and Taiwan. The present study represents the first record of N. exocoeti from the South-West Indian Ocean region and the first record of E. naucrates as a host of any cymothoid isopod. Additionally, N. exocoeti has previously only been recorded as parasitising beloniform fish hosts and these data present the first evidence of a perciform host for this species. The novel behaviour observed in E. naucrates likely represents a means to remove external parasites.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.