Unusual pattern of adult male testis in a gonochore fish, Satanoperca pappaterra (Heckel, 1840) (Perciformes, Cichlidae)

The pantanal eartheater, Satanoperca pappaterra (Heckel, 1840), is widely distributed throughout South America. A sedentary, benthopelagic species that inhabits lotic and lentic freshwater environments, it has iliophagic feeding habits and cares for its offspring (Fernandes et al., 2002; Kullander, 2003). In some reservoirs of the Parana River basin in Brazil, it is considered an exotic species and is exploited by commercial fishing, such as in the Itaipu Reservoir, where it is sold extensively in filleted form (Fernandes et al., 2002).