Gnathia grandilaris n. sp. (Crustacea, Isopoda, Gnathiidae) parasitizing two species of requiem shar
June 27th, 2008 | by admin |Gnathia grandilaris n. sp. (Crustacea, Isopoda, Gnathiidae) parasitizing two species of requiem sharks from Lizard Island, Great Barrier Reef, Australia.
Third stage juveniles (praniza 3) of Gnathia grandilaris n. sp. were collected from the gill filaments and septa of five requiem sharks, including a white tip reef shark, Triaenodon obesus, and four grey reef sharks, Carcharinus amblyrhynchos at Lizard Island, Great Barrier Reef, Australia, in March 2002. Some juvenile gnathiids were then maintained in fresh sea water until they moulted to adults. Adult males appeared 19 days following detachment of juveniles from host fishes, but no juveniles moulted successfully into females. The current description is based therefore on brightfield and scanning electron microscopy observations of adult males and third stage juveniles. Unique features of the male include the triangular-shaped inferior medio-frontal process, two areolae on the dorsal surface of the pylopod and a slender pleotelson (twice as long as wide) with lateral concavities. The third stage juvenile has distinctive white pigmentation on the black pereon when alive, while the mandible has nine triangular backwardly-directed teeth. This species has the largest male and third stage juvenile of any Gnathia spp. from Australia and of any gnathiid isopod associated with elasmobranchs.
Coetzee M, Smit N, Grutter A, Davies A.