Orientatractis moravecin. sp. andRondonia rondoniTravassos, 1920 (Nematoda: Atractidae), parasites ofPimelodus blochii(Osteichthyes, Pimelodidae) from the Acre and Xapuri Rivers, Western Amazon, Brazil

Abstract

The fish fauna in the State of Acre represents 10·7% of all fish species recorded from Brazil, but, despite this, there are few fish parasite studies in this area. The recent expansion of fish farming in Acre prompted a need for helminthological studies of the most commonly consumed fish species in the area, Pimelodus blochii (Pimelodidae). The aim of this study was to analyse the helminth fauna of P. blochii from the Acre and Xapuri Rivers in Northwestern Brazil. Numerous nematodes were collected from the intestine and two species of the family Atractidae were identified: Rondonia rondoni Travassos, 1920 and Orientatractis moraveci n. sp. The new species is distinguished from its congeners mainly by having: 10 pairs of caudal papillae (3 pairs pre-cloacal, 2 pairs ad-cloacal and 5 pairs post-cloacal); unequal spicules of 161-198 and 69-100 µ m long; and a gubernaculum 38-58 µ m long with an antero-lateral process. Morphological and ultrastructural data on O. moraveci n. sp. and R. rondoni are presented, in addition to new genetic data based on partial 18S rDNA and 28S rDNA. The taxonomic status of Labeonema synodontisi (Vassiliadès, 1973) is discussed, suggesting that it should be returned to the genus Raillietnema.

Community structure of metazoan parasites from Pimelodus blochii in two rivers of the Western Brazilian Amazon: same seasonal traits, but different anthropogenic impacts

“…Currently, there are no studies regarding the ecology of parasite communities from the catfish Pimelodus blochii Valenciennes (Siluriformes: Pimelodidae); studies have been focused solely on taxonomy of parasites and species catalogue (Gil de Pertierra 2004; Luque and Tavares 2007;Kohn et al 2007;Luque et al 2011;Mendoza-Palmero and Scholz 2011;Orélis-Ribeiro and Bullard 2015;Cavalcante et al 2016Cavalcante et al , 2018. Pimelodus blochii has economic importance and is widely distributed in South America (Lundberg and Littmann 2003;Froese and Pauly 2018); therefore, the community dynamics of parasites from this fish should be better understood.…”

Helminth diversity in Pimelodus blochii Valenciennes, 1840 (Osteichthyes: Pimelodidae) in two Amazon Rivers

“…The nematodes were clarified in glycerine and the trematodes were stained with Meyer's paracarmine, cleared in clove oil, and mounted in Canada Balsam. The helminths were counted, measured, and identified to the highest taxonomic level as possible, according to Moravec (1998), Thatcher (2006), Luque et al (2011), and Cavalcante et al (2017Cavalcante et al ( , 2018.…”

“…The use of this species in human feeding arouses the interest in studying its parasites, especially in investigating the occurrence of parasites of human interest. Concerning helminth parasites, most of the studies carried out for this host were species lists (Kohn et al 2007;Luque and Tavares 2007;Luque et al 2011;Martins 2018) or species descriptions (Gil de Pertierra 2004; Mendoza-Palmero and Scholz 2011; Orélis-Ribeiro and Bullard 2015; Cavalcante et al 2017;Cavalcante et al 2018;Negreiros et al 2019a;Negreiros et al 2020). There are only two studies which investigated the helminth community structure of P. blochii (Negreiros et al 2018(Negreiros et al , 2019b.…”

A new species of Orientatractis (Nematoda: Cosmocercoidea: Atractidae) parasite of Yellow-Spotted Amazon River Turtle, Podocnemis unifilis Troschel, 1848 (Testudines: Podocnemididae) in Brazilian Amazon

“…Orientatractis Petter, 1966 comprises nematodes parasitic in fishes, amphibians, and reptiles. Currently, the genus includes 10 valid species, namely: Orientatractis levanhoai Petter (1966) (type-species), Orientatractis leiperi Buckley (1969) , Orientatractis campechensis González-Solís and Moravec (2004) , Orientatractis chiapasensis González-Solís and Moravec (2004) , Orientatractis asymmetrica Gibbons and Platt (2006) , Orientatractis hamabatrachos Bursey et al, 2014 , Orientatractis mekongensis Moravec et al, 2015 , Orientatractis brycini González-Solís and Mariaux (2017) , Orientatractis moraveci Cavalcante et al (2017) and Orientatractis longicaudata Liu et al, 2018 ; Jesus et al (2020) . Among these, four species were described from chelonians, O. asymmetrica and O .…”