Dero ( Allodero ) lutzi Michaelsen , 1926 ( Oligochaeta : Naididae ) associated with Scinax fuscovarius ( Lutz , 1925 ) ( Anura : Hylidae ) from Semi-deciduous Atlantic Rain Forest , southern Brazil

Amphibians are hosts for a wide variety of ectoand endoparasites, such as protozoans and parasitic worms. Naididae is a family of Oligochaeta whose species live on a wide range of substrates, including mollusks, aquatic macrophytes, sponges, mosses, liverworts, and filamentous algae. However, some species are known as endoparasitic from vertebrates, such as Dero (Allodero) lutzi, which is parasitic of the urinary tracts of frogs, but also have a free-living stage. Specimens in the parasitic stage lack dorsal setae, branchial fossa, and gills. Here we report the occurrence of D. (A.) lutzi associated with anuran Scinax fuscovarius from Semi-deciduous Atlantic Rain Forest in southern Brazil. The study took place at the Caiuá Ecological Station, Diamante do Norte, Paraná, southern Brazil. Seven specimens of S. fuscovarius were examined for parasites but only one was infected. Parasites occurred in ureters and urinary bladder. Previous records of this D. (A.) lutzi include the Brazilian States of Santa Catarina, São Paulo, Rio de Janeiro, and Minas Gerais, as well as Cuba and North America. This is a new locality record for this species in Brazil. Reports of Dero (Allodero) lutzi are rare, due to difficulty of observation, and such events are restricted only the fortuitous cases. It is important to emphasize the necessity of future studies, which are fundamental to the understanding of biological and ecological aspects of this species.

The subgenus Allodero was erected by Sperber (1948) within the genus Dero (Naididae, Oligochaeta) for parasitic or symbiotic species known from Asia, Africa, and South America (Harman, 1971).Allodero, Aulophorus and Dero are considered subgenera of Dero by some authors (e.g.Milligan, 1997;Kathman and Brikhurst, 1998;Wetzel et al., 2012).However, Cekanovskaya (1962) and Liang (1964) considered Dero and Aulophorus as separate genera, while the latter author also separated Allodero at the generic level.More recently, Aulophorus was listed as a full genus (Timm, 1999).However, we prefer to refer individuals from this study as Dero (Allodero) lutzi until a revision of the subgenus Allodero is effectively conducted.
The subgenus Allodero consists only of one species, D. (Allodero) lutzi Michaelsen, 1926.Dero (Allodero) lutzi is an endoparasitic of the urinary tracts of frogs of the genus Hyla (Maldonado and Oliveira, 1982;Rodrigues and Maldonado Junior, 1982), which also have a freeliving stage.Specimens in the parasitic stage lack dorsal setae, branchial fossa, and gills, but when cultured in a free-living form, they developed dorsal setae as well as caudal fossa and gills (Harman and Lawler, 1975).Here we report the occurrence of the endoparasitic Oligochaeta, Dero (Allodero) lutzi in the snouted tree frog, Scinax fuscovarius, from Semi-deciduous Atlantic Rain Forest in southern Brazil.

Material and Methods
This study took place in the Caiuá Ecological Station (22° 37' S and 52° 50' W, 268 m asl), in the municipality of Diamante do Norte, Paraná, Brazil.The region is inserted in the Semi-deciduous Atlantic Rain Forest.Specimens of Scinax fuscovarius (n = 7, mean SVL = 40.9mm, ±3.7 SD and mean body weight 4.5 g, ±1.4 SD) were collected in temporary and permanent ponds during visual encounters surveys in February, April, and October 2012.Individuals were taken to the laboratory where they were euthanatized with Lidocaine 5%.Subsequently, the lungs, digestive tract, urinary tract, muscle, skin, spleen, and liver were examined for parasites.The Oligochaeta were identified in semi permanent slides.All anurans are housed at the zoological collection of the Universidade Federal de Goiás (ZUFG), Goiânia, Goiás, central Brazil 7190,7208).Voucher parasite specimens are housed at the Helminthological collection of the Instituto Oswaldo Cruz (CHIOC), Rio de Janeiro, Rio de Janeiro, Brazil (CHIOC 35863).The current nomenclature of anurans follows Faivovich et al. (2005), Lema and Martins (2011), Frost (2013).

Results and Discussion
Seven specimens of Scinax fuscovarius were examined for parasites.Analyses of the treefrogs demonstrated that one specimen (male, SVL = 40.75mm, weight = 4.53 g) was infected by Dero (Allodero) lutzi (n = 14, mean length = 3.06 mm, ±0.51 SD; Figure 1), which were found in ureters and urinary bladder.These oligochaetes are freeliving animals (Rodrigues and Maldonado Junior, 1982), which are adapting to parasitism, since the ecological conditions of the bladder and ureters of amphibians resemble those of the external liquid environment used by the frogs.However, the exact route of transmission of naids to frogs is unknown, but previous studies suggest that frogs are infected during the larval stage (Harman and Lawler, 1975).
Only Dero is known to use frogs for transport and as hosts among the Brazilian freshwater genera of naidids (Righi, 1984;Lopez et al., 1999).As example, Dero superterrenus Michaelsen, 1912 are free-living inhabitants of tank bromeliads and tree holes and can use amphibians to disperse (Lopez et al., 1999).Laboratory experiments support the hypothesis that the phoretic behaviour presented by D. superterrenus is stimulated by chemical substances released by amphibian skins (Lopez et al., 2005).Lopez et al. (2005) suggest that if D. (A.) lutzi use the same chemical substances used by D. superterrenus to find their amphibian vectors, it will strengthen the hypothesis that parasitic and phoretic behaviours using frogs are evolutionarily linked in the annelid Dero group.Thereby, D. superterrenus and D. (A.) lutzi might have shared a close common ancestor with parasitic or phoretic behavior (Lopez et al., 2005).
Reports of Dero (A.) lutzi are rare, due to difficulty of observation.Such events are restricted to fortuitous cases.In this context, it is important to emphasize the need for future studies to the understanding of biological and ecological aspects of D. (A.) lutzi.

Table 1 .
. The reported of S. fuscovarius as host of D. (A.) lutzi represents a new host record for this Oligochaeta endoparasite.Previous records of Dero (A.) lutzi include the Brazilian States of Santa Catarina, São Paulo, Rio de Janeiro, and Checklist of anuran species host of Dero (Allodero) lutzi.BRA, Brazil: MG, Minas Gerais; PR, Paraná; RJ, Rio de Janeiro; SC, Santa Catarina; SP, São Paulo; CUB, Cuba; VEN, Venezuela; USA, United States of America; b This study; c name unknown (possible confusion with Hyla bivittata). a