First report of a histozoic Henneguya (Cnidaria, Endocnidozoa) infecting a synbranchid potamodromous fish from South America: Morphostructural and biological data

In this study, a Henneguya myxosporean species is described to infect an ecological, biological, and evolutionary important fish from Amazon biome. The myxosporean was found in the skin of only one specimen of marbled swamp eel, Synbranchus marmoratus caught in a small stream from Peruvian Amazon floodplain. Mature myxospores have ovoid shape from the valvular view, measuring 32.2 & PLUSMN; 0.6 gm (31.6-32.8) in total length, 21.5 & PLUSMN; 0.3 gm (21.2-21.8) in spore body length, 11.7 & PLUSMN; 0.5 gm (11.2-12.2) in width and 10.6 & PLUSMN; 0.9 gm (9.7-11.5) in thickness. Non-bifurcate caudal appendage, measuring 10.7 & PLUSMN; 0.4 gm (10.3-11.1) in length. Two polar capsules elongated aubergine in shape, equal in size and measuring 4.9 & PLUSMN; 0.2 gm (4.7-5.1) in length and 3.1 & PLUSMN; 0.5 gm (2.6-3.6) in width. Polar tubules coiled in 7-8 turns. This is the first report of a Henneguya species parasitizing a fish of the order Synbranchiformes from Amazon basin and the first to describe this parasite infecting a potamodromous fish from South America.

Automated summary

A myxosporean species, identified as Henneguya, was found infecting a fish species called Synbranchus marmoratus in the Amazon biome. The myxosporean was discovered within the skin of a marbled swamp eel specimen caught in a small stream in the Peruvian Amazon floodplain. This is the first known instance of a Henneguya species parasitizing a fish of the Synbranchiformes order in the Amazon basin, as well as the first description of this parasite infecting a potamodromous fish in South America.