Studying the variables that describe the spatial ecology of threatened species allows us to identify and prioritize areas that are critical for species conservation. To estimate the home range and core area of the Endangered (EN) Amazon river dolphin Inia geoffrensis, 23 individuals (6♀, 17♂) were tagged during the rising water period in the Amazon and Orinoco river basins between 2017 and 2018. The satellite tracking period ranged from 24 to 336 d (mean ± SE = 107 ± 15.7 d), and river dolphin movements ranged from 7.5 to 298 km (58 ± 13.4 km). Kernel density estimates were used to determine minimum home ranges at 95% (K95 = 6.2 to 233.9 km2; mean = 59 ± 13.5 km2) and core areas at 50% (K50 = 0.6 to 54.9 km2; mean = 9 ± 2.6 km2). Protected areas accounted for 45% of the K50 estimated core area. We observed dolphin individuals crossing country borders between Colombia and Peru in the Amazon basin, and between Colombia and Venezuela in the Orinoco basin. Satellite tracking allowed us to determine the different uses of riverine habitat types: main rivers (channels and bays, 52% of recorded locations), confluences (32%), lagoons (9.6%), and tributaries (6.2%). Satellite monitoring allowed us to better understand the ecological preferences of the species and demonstrated the importance of maintaining aquatic landscape heterogeneity and spatial connectivity for effective river dolphin conservation.

A new parasitic copepod species, Ergasilus turkayi n. sp., found on the gills of the Holland's piranha, Serrasalmus hollandi Jégu, 2003, in the Paragua River, Bolivia, is described based on 10 adult females. Th e new species presents a triangular-shaped cephalothorax, spinules on interpodal plates and aesthetascs on antennule -two aesthetascs on the sixth, and one aesthetasc plus two setae on the fi ft h segment. Additionally, the second abdominal somite of E. turkayi n. sp. bears an anal pseudoperculum, a dorsal and elongate projection which is usually absent or vestigial in poecilostome families within the Cyclopoida but that was never reported in species of Ergasilidae.

ResumenEl presente trabajo analiza la diversidad de parásitos monogenoideos como un carácter independiente, esperando que por su alta especifi cidad, éstos parásitos puedan caracterizar las poblaciones de sus hospederos, la piraña blanca, Serrasalmus rhombeus. El estudio se llevó acabo en cuatro sub-cuencas de la Cuenca Amazónica Boliviana (Iténez, Beni, Madre de Dios e Ichilo); se obtuvieron 1135 parásitos, los cuales fueron agrupados en seis géneros y once especies: Anacanthorus jegui, A. amazonicus, A. rondonensis, A. gravihamulatus, A. sciponophallus AbstractThe present work analyse monogenoids parasite diversity as one independent character, hoping they can characterize the white piranha (Serrasalmus rhombeus) populations by its high specifi city. Study was carried out in four sub-basins (Iténez, Beni, Madre de Dios e Ichilo) from the Bolivian Amazon Basin. A total of 1135 parasites were obtained, belonging to six genera and 11 species: Anacanthorus jegui, A. amazonicus, A. rondonensis, A. gravihamulatus, A. sciponophallus