Capillostrongyloides arapaimae sp. n. (Nematoda: Capillariidae), a new intestinal parasite of the arapaima Arapaima gigas from the Brazilian Amazon

Abstract

A new nematode species, Capillostrongyloides arapaimae sp. n., is described from the intestine and pyloric caeca of the arapaima, Arapaima gigas (Schinz), from the Mexiana Island, Amazon river delta, Brazil. It is characterized mainly by the length of the spicule (779-1,800 µm), the large size of the body (males and gravid females 9.39-21.25 and 13.54-27.70 mm long, respectively) and by the markedly broad caudal lateral lobes in the male. It is the third species of genus Capillostrongyloides reported to parasitize Neotropical freshwater fishes. During recent investigations on the helminth para- sites of the wild and cultured arapaima Arapaima gigas (Schinz) in the Mexiana Island, Brazilian Amazon, con- specific capillariid nematodes referable to Capillostrongy- loides Freitas and Lent were recovered from the anterior part of the intestine and caeca of this fish. Their detailed study has shown that they represent a previously unde- scribed species, which is described herein.