Two new species of Anacanthorus (Monogenoidea, Dactylogyridae) parasitizing serrasalmid fish in Brazil.

During studies on fish parasites, two new species of Anacanthorus were found parasitizing serrasalmid fishes, Anacanthorus simpliciphallus sp. n. from the hybrid Piaractus mesopotamicus x Piaractus brachypomus and Anacanthorus brandtii sp. n. from Serrasalmus brandtii. Anacanthorus simpliciphallus sp. n. resembles Anacanthorus reginae in the morphology of the male copulatory organ (MCO) and accessory piece but differs from A. reginae in terms of the smaller size of the accessory piece, which corresponds approximately half the size of the MCO and by the presence of a conspicuous metraterm, with a membranous terminal region. Anacanthorus brandtii sp. n. differs from Anacanthorus scapanus by the expansion of the accessory piece, from Anacanthorus jegui by the ratio MCO (male copulatory organ) /AP (accessory piece) and by the expansion of hook shank, from Anacanthorus sciponophallus and A. reginae by the ratio MCO/AP. Anacanthorus brandtii sp. n. can be distinguished from A. reginae and A. simpliciphallus sp.n. by the size of hooks which is similar in A. reginae and A. simpliciphallus sp. n. and dissimilar in A. brandtii sp. n. The two new species also differ from each other by the expansion of shank.

Sebekia sp. (Eupentastomida, Sebekidae) in Pygocentrus piraya (Actinopterygii: Serrasalmidae) from marginal lagoons of the middle São Francisco River basin, Brazil.

Pygocentrus piraya is an endemic species of the São Francisco River basin. In this study, 342 carnivorous fish were examined, nymphs specimens of Sebekia sp. and its ecological indexes are recorded only in piranhas, of the total of 53 collected from three marginal lagoons of the middle São Francisco River basin: 17 specimens from Curral de Varas lagoon; 15 from Maris lagoon, both of state of Minas Gerais; and 21 specimens from Mocambo lagoon, state of Bahia. The prevalence (P) and mean abundance (MA) of Sebekia sp. nymphs in intermediate hosts were as follows: in Curral de Varas lagoon, P = 11.8%, MA = 0.18; in Maris lagoon, P = 46.6%, MA = 0.47; and in Mocambo lagoon, P = 14.3%, MA = 1.05. Despite the lower number of fish examined from Maris lagoon, this lagoon had the highest number of piranhas (seven) parasitized by Sebekia sp. Pentastomids have zoonotic importance and evaluation of the indirect life cycle of sebekids in lagoons is necessary for defining the intermediate and final hosts involved. This record is novel and stems from collection of piranhas in the marginal lagoons of the São Francisco River, in the states of Minas Gerais and Bahia, Brazil.

Metazoan endoparasites of Acestrorhynchus lacustris (Actinopterygii: Acestrorhynchidae) from lagoons bordering the upper and middle São Francisco river basin, Brazil.

The endoparasitic fauna of Acestrorhynchus lacustris from eight marginal lagoons of the upper and middle São Francisco river basin, Brazil, is recorded here for the first time. For this, a total of 106 specimens of A. lacustris were collected. Eighteen helminth species were found. The taxa recorded were phylum Platyhelminthes: one metacercaria of Clinostomum sp. (Trematoda: Clinostomidae) and plerocercoid larvae of unidentified species (Eucestoda: Proteocephalidae gen. sp.); phylum Acanthocephala: juvenile of Quadrigyrus sp.; and phylum Nematoda: larvae of Brevimulticaecum sp., Contracaecum sp. Type1, Contracaecum sp. Type2, Hysterothylacium sp., Gnathostoma sp., Spiroxys sp., juvenile and adult specimens of Freitascapillaria sp., Paracapillaria piscicola, Capillariidae gen. sp., Procamallanus (Spirocamallanus) hilarii, Procamallanus (S.) inopinatus, Procamallanus (S.) saofranciscencis, Travassosnema travassosi paranaensis, Cystidicoloides fischeri and Spinitectus rodolphiheringi. Proteocephalidae gen. sp., Contracaecum sp. Type1 and Travassosnema t. paranaensis were present in all eight lagoons with high parasitic indexes. Proteocephalidae gen. sp., Brevimulticaecum sp., Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii, C. fischeri and S. rodolphiheringi are new records for A. lacustris. The known geographical distribution of Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii and Travassosnema t. paranaensis has now been extended to the São Francisco river basin.

Sebekia sp. (Eupentastomida, Sebekidae) in Pygocentrus piraya (Actinopterygii: Serrasalmidae) from marginal lagoons of the middle São Francisco River basin, Brazil / Sebekia sp. (Eupentastomida, Sebekidae) em Pygocentrus piraya (Actinopterygii: Serrasalmidae) de lagoas marginais da bacia do médio rio São Francisco, Brasil

Pygocentrus piraya is an endemic species of the São Francisco River basin. In this study, 342 carnivorous fish were examined, nymphs specimens of Sebekia sp. and its ecological indexes are recorded only in piranhas, of the total of 53 collected from three marginal lagoons of the middle São Francisco River basin: 17 specimens from Curral de Varas lagoon; 15 from Maris lagoon, both of state of Minas Gerais; and 21 specimens from Mocambo lagoon, state of Bahia. The prevalence (P) and mean abundance (MA) of Sebekia sp. nymphs in intermediate hosts were as follows: in Curral de Varas lagoon, P = 11.8%, MA = 0.18; in Maris lagoon, P = 46.6%, MA = 0.47; and in Mocambo lagoon, P = 14.3%, MA = 1.05. Despite the lower number of fish examined from Maris lagoon, this lagoon had the highest number of piranhas (seven) parasitized by Sebekia sp. Pentastomids have zoonotic importance and evaluation of the indirect life cycle of sebekids in lagoons is necessary for defining the intermediate and final hosts involved. This record is novel and stems from collection of piranhas in the marginal lagoons of the São Francisco River, in the states of Minas Gerais and Bahia, Brazil.(AU)

Pygocentrus piraya é espécie endêmica da bacia do rio São Francisco. Neste estudo, 342 peixes carnívoros foram examinados, espécimes ninfais de Sebekia sp. e seus índices ecológicos são registrados apenas em piranhas, do total de 53 coletadas em três lagoas marginais da bacia do médio rio São Francisco: 17 espécimes da lagoa Curral de Varas; 15 da lagoa Maris, ambas no estado de Minas Gerais; e 21 espécimes da lagoa Mocambo, estado da Bahia. A prevalência (P) e a abundância média (AM) das ninfas de Sebekia sp. nos hospedeiros intermediários foram: na lagoa Curral de Varas P = 11,8%, AM = 0,18; na lagoa Maris, P = 46,6%, AM = 0,47; e na lagoa Mocambo, P = 14,3%, AM = 1,05. A lagoa Maris, apesar do menor número de peixes examinados, foi a que apresentou maior número de piranhas parasitadas (sete) por Sebekia sp. Os pentastomídeos têm importância zoonótica, e a avaliação do ciclo de vida indireto dos sebekídeos em lagoas é necessária para definir os hospedeiros intermediários e finais envolvidos. Este registro é inédito e decorre da coleta de piranhas nas lagoas marginais do rio São Francisco, nos estados de Minas Gerais e Bahia, Brasil.(AU)

Metazoan endoparasites of Acestrorhynchus lacustris (Actinopterygii: Acestrorhynchidae) from lagoons bordering the upper and middle São Francisco river basin, Brazil / Metazoários endoparasitos de Acestrorhynchus lacustris (Actinopterygii: Acestrorhynchidae) de lagoas marginais da bacia do alto e médio rio São Francisco, Brasil

The endoparasitic fauna of Acestrorhynchus lacustris from eight marginal lagoons of the upper and middle São Francisco river basin, Brazil, is recorded here for the first time. For this, a total of 106 specimens of A. lacustris were collected. Eighteen helminth species were found. The taxa recorded were phylum Platyhelminthes: one metacercaria of Clinostomum sp. (Trematoda: Clinostomidae) and plerocercoid larvae of unidentified species (Eucestoda: Proteocephalidae gen. sp.); phylum Acanthocephala: juvenile of Quadrigyrus sp.; and phylum Nematoda: larvae of Brevimulticaecum sp., Contracaecum sp. Type1, Contracaecum sp. Type2, Hysterothylacium sp., Gnathostoma sp., Spiroxys sp., juvenile and adult specimens of Freitascapillaria sp., Paracapillaria piscicola, Capillariidae gen. sp., Procamallanus (Spirocamallanus) hilarii, Procamallanus (S.) inopinatus, Procamallanus (S.) saofranciscencis, Travassosnema travassosi paranaensis, Cystidicoloides fischeri and Spinitectus rodolphiheringi. Proteocephalidae gen. sp., Contracaecum sp. Type1 and Travassosnema t. paranaensis were present in all eight lagoons with high parasitic indexes. Proteocephalidae gen. sp., Brevimulticaecum sp., Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii, C. fischeri and S. rodolphiheringi are new records for A. lacustris. The known geographical distribution of Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii and Travassosnema t. paranaensis has now been extended to the São Francisco river basin.(AU)

A fauna endoparasitária de Acestrorhynchus lacustris de oito lagoas marginais da bacia do alto e médio rio São Francisco, Brasil, foi registrada pela primeira vez. Para isso, um total de 106 espécimes de A. lacustris foi coletado. Dezoito espécies de helmintos foram encontradas. Os táxons relacionados foram do Filo Platyhelminthes: uma metacercária de Clinostomum sp. (Trematoda: Clinostomidae); larvas plerocercoides de espécie não identificada (Eucestoda: Proteocephalidae gen. sp.); Filo Acanthocephala: juvenil de Quadrigyrus sp.; e Filo Nematoda: larvas de Brevimulticaecum sp., Contracaecum sp. Tipo1, Contracaecum sp. Tipo2, Hysterothylacium sp., Gnathostoma sp., Spiroxys sp.; juvenis e adultos de Freitascapillaria sp., Paracapillaria piscicola, Capillariidae gen. sp., Procamallanus (Spirocamallanus) hilarii, Procamallanus (S.) inopinatus, Procamallanus (S.) saofranciscencis, Travassosnema travassosi paranaensis, Cystidicoloides fischeri e Spinitectus rodolphiheringi. Proteocephalidae gen. sp., Contracaecum sp. Tipo1 e Travassosnema t. paranaensis foram compartilhadas entre todas as oito lagoas com altos índices parasitários. Proteocephalidae gen. sp., Brevimulticaecum sp., Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii, C. fischeri e S. rodolphiheringi são novos registros para A. lacustris. Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii e Travassosnema t. paranaensis têm sua distribuição geográfica estendida para a bacia do rio São Francisco.(AU)

Argulus elongatus (Branchiura, Argulidae) in fish in the upper São Francisco river, Brazil.

Among 164 fish from the upper São Francisco river, caught in the Três Marias reservoir (18º 12' 59" S; 45º 17' 34" W) or downstream from this reservoir (18º 12' 32" S; 45º 15' 41" W) in 2007, 2008, 2016 and 2017, four specimens of Argulus elongatus Heller, 1857 were found, one specimen per fish, in the following host species: Brycon orthotaenia Günther (two fish parasitized out of 38 examined) and Salminus hilarii Valenciennes (one fish parasitized out of 45 examined) (both in Bryconidae); and Metynnis lippincottianus (Cope) (one fish parasitized out of 81 examined) (Serrasalmidae). This opportunistic ectoparasite deserves attention even in the case of low infestation in fish in a natural water system. This is the first record of a branchiuran species in B.orthotaenia; the host list of A.elongatus is extended through addition of the three fish species examined in this study, and the known Brazilian geographical distribution of this argulid is enlarged to the São Francisco river basin.

Argulus elongatus (Branchiura, Argulidae) in fish in the upper São Francisco river, Brazil / Argulus elongatus (Branchiura, Argulidae) de peixes do alto rio São Francisco, Brasil

Among 164 fish from the upper São Francisco river, caught in the Três Marias reservoir (18º 12 59” S; 45º 17 34” W) or downstream from this reservoir (18º 12 32” S; 45º 15 41” W) in 2007, 2008, 2016 and 2017, four specimens of Argulus elongatus Heller, 1857 were found, one specimen per fish, in the following host species: Brycon orthotaenia Günther (two fish parasitized out of 38 examined) and Salminus hilarii Valenciennes (one fish parasitized out of 45 examined) (both in Bryconidae); and Metynnis lippincottianus (Cope) (one fish parasitized out of 81 examined) (Serrasalmidae). This opportunistic ectoparasite deserves attention even in the case of low infestation in fish in a natural water system. This is the first record of a branchiuran species in B.orthotaenia; the host list of A.elongatus is extended through addition of the three fish species examined in this study, and the known Brazilian geographical distribution of this argulid is enlarged to the São Francisco river basin.(AU)

De 164 peixes do alto rio São Francisco, capturados no Reservatório de Três Marias (18º 12 59” S; 45º 17 34” O) ou à jusante dele (18º 12 32” S; 45º 15 41” O), em 2007, 2008, 2016 e 2017, quatro espécimes de Argulus elongatus Heller, 1857 foram encontrados, sendo um branquiúro por peixe nas seguintes espécies de hospedeiros: Brycon orthotaenia Günther (dois peixes parasitados de 38 peixes examinados), Salminus hilarii Valenciennes (um peixe parasitado de 45 examinados) ambos Bryconidae, e Metynnis lippincottianus (Cope) (um peixe parasitado de 81 examinados) - Serrasalmidae. Esse ectoparasito oportunista merece atenção, mesmo no caso de infestações baixas em peixes de ambientes hídricos naturais. Esse é o primeiro registro de Branchiura em B.orthotaenia. A lista de hospedeiros de A. elongatus é ampliada com a adição das três espécies de peixes examinadas neste estudo. A distribuição geográfica conhecida desse argulídeo no Brasil, é ampliada para a bacia do rio São Francisco.(AU)