Callitetrarhynchus gracilis (Rudolphi, 1819) Pintner, 1931 (Cestoda: Trypanorhyncha) parasitizing the musculature of Sardinella brasiliensis (Steindachner, 1879) (Actinopterygii) off the coast of the state of Rio de Janeiro, Brazil.

Cestodes of the order Trypanorhyncha can frequently be found infecting the muscles of several marine fish species, and lead to a repugnant aspect of the fish and rejection by consumers. The Brazilian sardinella, Sardinella brasiliensis, occurs from the Gulf of Mexico and the Caribbean to northern Uruguay. In southeastern Brazil, fishing for the species is very intensive since it generates significant revenue as one of the most commonly consumed fish and an important element of the canned fish industry. The aims of the present study were to identify and report the occurrence of tiny cestodes (3 mm-6.6 mm) in the musculature of Brazilian sardinella that were purchased in the São Pedro fish market in the municipality of Niterói, state of Rio de Janeiro, Brazil. From October 2013 to November 2016, 75 specimens of S. brasiliensis were investigated. The trypanorhynch cestodes encountered were identified as plerocerci of Callitetrarhynchus gracilis using morphological, morphometric and molecular data. Parasitic indices were calculated, and the cestodes infection of the musculature of Brazilian sardinella had the following values: prevalence, 40%; mean intensity, 3.47; mean abundance, 1.39; and range of infection, 1-18, specimens. The presence of this trypanorhynch cestode in the musculature of Brazilian sardinella is an important indicator of fish hygiene.

Gobioides broussonnetii (Gobiidae): a new host for Pterobothrium crassicolle (Trypanorhyncha) on Marajó Island, northern Brazil.

In the present study, the cestoid Pterobothrium crassicolle Diesing, 1850 (Trypanorhyncha), was observed parasitizing specimens of the violet goby (Gobioides broussonnetii Lacepède, 1800) collected from the estuary of the Paracauarí River on Marajó Island in the north of the Brazilian state of Pará, between January 2009 and December 2010. Tissue samples were analyzed, which led to identification of blastocysts containing plerocercoid larvae. These larvae were processed for scanning electron microscopy. Sixty G. broussonnetii specimens were dissected, and P. crassicolle was found in 48 (80%) of them. The violet goby, G. broussonnetii, is a new host for P. crassicolle.

Trypanorhyncha cestodes of hygienic-sanitary importance infecting flounders Paralichthys patagonicus Jordan, 1889 and Xystreurys rasile (Jordan, 1891) of the Neotropical region, Brazil.

From February 2007 to July 2010, 27 specimens of Paralichthys patagonicus, and from September to December 2010, 30 specimens of Xystreurys rasile were purchased from fish markets in the municipalities of Cabo Frio and Rio de Janeiro, State of Rio de Janeiro, Brazil. The fishes were measured, necropsied, filleted, and further had their organs investigated. In P. patagonicus, 19 (70, 3 %) were parasitized with metacestodes of Trypanorhyncha species: Nybelinia erythraea, N. lingualis, Heteronybelinia nipponica, Pterobothrium crassicolle, Grillotia carvajalregorum, and Callitetrahynchus gracilis. In X. rasile, 17 (56, 6 %) were parasitized with metacestodes: N. erythraea, N. lingualis, H. nipponica, and G. carvajalregorum. The parasitological indices of prevalence, intensity, mean intensity, abundance, mean abundance, range of infection, and infection sites of each parasite species are presented. This is the first report of Trypanorhyncha cestodes parasitizing specimens of P. patagonicus and X. rasile. These cestodes were studied due to their importance during fish sanitary inspection, if one considers the harm that the repulsive aspect of infected meat causes to consumers.