Occurrence of Rhinoptericola megacantha ( CESTODA , TRYPANORHYNCHA ) in new host and new location

The genus Rhinoptera, Cuvier, 1829, is represented by eight species of rays, distributed around the world. They are present in tropical, subtropical and warm-temperate waters, except around Oriental Pacific Island (Last and Stevens, 1994). Only two species occurred in Brazilian coast: the cownose ray Rhinoptera bonasus (Mitchill, 1815) and the ticon cownose ray R. brasiliensis (Muller, 1836) (Cavalcanti et al., 1997). These differentiate morphologically: R. bonasus usually has seven series of plates in both jaws, while R. brasiliensis teeth are typically arranged in series of nine (Bigelow and Schroeder, 1953). Rhinoptera brasiliensis is distributed from Rio de Janeiro to Rio Grande do Sul States, 23°–32°S (Bigelow and Schroeder, 1953; Menni and Stehmann, 2000). 

The genus Rhinoptera, Cuvier, 1829, is represented by eight species of rays, distributed around the world.They are present in tropical, subtropical and warm-temperate waters, except around Oriental Pacific Island (Last and Stevens, 1994).Only two species occurred in Brazilian coast: the cownose ray Rhinoptera bonasus (Mitchill, 1815) and the ticon cownose ray R. brasiliensis (Muller, 1836) (Cavalcanti et al., 1997).These differentiate morphologically: R. bonasus usually has seven series of plates in both jaws, while R. brasiliensis teeth are typically arranged in series of nine (Bigelow and Schroeder, 1953).Rhinoptera brasiliensis is distributed from Rio de Janeiro to Rio Grande do Sul States, 23°-32°S (Bigelow and Schroeder, 1953;Menni and Stehmann, 2000).


In trawls in the southern and southeastern Brazil, a significant portion of shrimp by-catch is discarded at sea, either by treating species without commercial value or juveniles of species of economic interest (D'incão et al, 2002).Some species from elasmobranch fishes are present in fishery shrimp by-catch (Lessa et. al, 1986;Voreen and Klippel, 2005), and many elasmobranchs are endangered due to the characteristics of slow growth, late sexual maturity and low fecundity (Stevens et al., 2000).
The actually status of Rhinoptera brasiliensis is "endangered", according to IUCN -Red List of Threatened Species, when the best available evidence indicates that it meets of the criteria for "endangered", and it is therefore considered to be facing a very high risk of extinction in the wild (Vooren and Lamónaca, 2013).
Studies about parasitological fauna of Brazilian elasmobranchs are rare.The aim of the present study was to report the first occurrence of Rhinoptericola megacantha in Rhinoptera brasiliensis, and the first occurrence of R. megacantha in Brazilian coast.
From April 2012 to April 2013 seven specimens of Rhinoptera brasiliensis were captured from shrimp fishery by-catch, Xiphopenaeus kroyeri, in southern and southeastern from Brazil.The specimens were found dead, and were stored in ice and taken to the laboratory to mensuration the mean length, mean width and mean weight.
It was reported in the same host in Gulf of Venezuela (Mayes and Brooks, 1980) and Gulf of Mexico (Call, 2007).This is the first report on the occurrence of Rhinoptericola megacantha in Brazil and the first report in host Rhinoptera brasiliensis.
These data contribute to the knowledge of the parasitological fauna of rays in the Brazilian coast.