Extreme sexual dimorphism suggests that the South American electric fish, Brachyhypopomus pinnicaudatus Hopkins (Copeia 1991(Copeia :151-161, 1991 is polygynous. No field studies have been conducted on the social behavior of this common gymnotiform species, in part because their nocturnal habits and densely vegetated habitat precludes direct observation in the field. We conducted mark-recapture studies on B. pinnicaudatus in Uruguay to gather indirect evidence of their breeding system. Sex ratios of adults were highly skewed toward females 2-3 weeks into the breeding season. Females moved twice as far as males on average (p= 0.016) and movement tracks of individual females overlapped one another but those of males did not. These data support the hypothesis that B. pinnicaudatus is polygynous or polygynandrous, and suggest that they use space in a manner consistent with exploded lek polygyny or iteroparous nest site polygynandry models. Fish detected within 2 m of each other were more aggregated than chance, both day and night, suggesting they maintain social groupings or alerting networks.

Pulmonary cryptococcosis was observed in a free-living adult female common toad (Bufo bufo) that was killed by a vehicle. Both lungs had various eosinophilic, monomorphic, and spherical to elliptical organisms identified as Cryptoccocus spp. The yeasts were demonstrated by Grocott's silver method and the periodic acid-Schiff reaction and the capsule was positive for mucin with a mucicarmine stain. The agent was confirmed by immunohistochemistry, using the monoclonal antibody anti-Cryptococcus neoformans, and by a polymerase chain reaction-based method using a C. neoformans-specific primer. This report, to the best of our knowledge, represents the first case of cryptococcosis in a common toad.