Gnathia pantherina sp. n. (Crustacea: Isopoda: Gnathiidae), a temporary ectoparasite of some elasmobranch species from southern Africa

Abstract

Abstract. Haematophagous larvae of a gnathiid isopod were collected from the gills, nares and buccal cavity of a single leopard catshark Poroderma pantherinum (Smith, 1838) at Jeffreys Bay and five puffadder shysharks Haploblepharus edwardsii (Voight, 1832) and one blackspotted electric ray Torpedo fuscomaculata Peters, 1855, at the De Hoop Nature Reserve on the South African south coast. Larvae were kept in fresh seawater until their moult into adult stages. The morphology of the adult males did not conform to that of any known species and they are therefore described as Gnathia pantherina sp. n. The descriptions of the adult male, female and praniza larva are based on light and scanning electron microscopy observations. Characteristic features of this species include the large size of all the final life-cycle stages, the deeply divided mediofrontal process of the male, the morphology of the pylopods and maxillipedes of the female, and the number of teeth on the mandibles (eight) and maxillules (seven) of the praniza larvae.

A note on the occurrence of praniza larvae of Gnathiidae (Crustacea, Isopoda) on fishes from Northeast of Pará, Brazil

“…The general characteristics of our specimens are similar to those reported for other species (Davies 1981, Smit et al 1999, Smit and Basson 2002. However, the comparison of our specimens with descriptions of other larvae descriptions (Table II) shows some differences, namely the relative small number of teeth on the mandible (7), and the lowest number of teeth (1) on the tip of the mandible, and the low number of setae in the pleotelson.…”

“…Prevalence and mean intensity were calculated according to Bush et al 1997. Ten praniza larvae, with origin in different host fish species, (total length: 2.09±0.12 mm, 1.8-2.26 mm) were dissected for anatomical studies following the recommendations described elsewhere (Smit et al 1999, Smit andBasson 2002). No attempts were made to moult the pranizae to adults.…”

“…Apparently these parasites are not host specific and were described from a number of hosts worldwide (Smit and Basson 2002, Smit and Davies 2004, Jones and Grutter 2005, Genc et al 2005. In some cases they can be very abundant: in Dentex dentex from the Western Mediterranean the prevalence of praniza larvae reached 85%, with a mean intensity of 20 parasites per fish (González et al 2004), and in Epinephelus aeneus from the North-Eastern Mediterranean 57.1% of the specimens were infected presenting a mean intensity of infection of 43.5 larvae per host (Genc et al 2005).…”

Infestation status of gnathiid isopod juveniles parasitic on Dusky grouper (Epinephelus marginatus) from the northeast Mediterranean Sea

“…Currently, it is difficult to identify species level in larvae stages of gnathiids (Kabata 1970;Cohen and Poore 1994;Heupel and Bennett 1999) because the taxonomy of this parasite is based predominately on the morphology of the free-living adult males (Smit and Basson 2002). In the warm season, gnathiid larvae transform (after the metamorphosis) into a parasitic form (praniza).…”

First record of Gnathia sp. an ectoparasitic isopod isolated from the coral reef fish, Heniochus acuminatus collected from the Gulf of Mannar region, southeast coast of India

“…The collection and fixation were done by removing the specimen alive from the gill chambers of the host body and immediately placed into 70 % ethanol. They are further dissected for anatomical studies following the recommendations described elsewhere (Smit et al 1999;Smit and Basson 2002). The taxonomy and fish names were updated according to (Froese and Pauly 2011).…”