Mollusca , Gastropoda , Succineidae , Omalonyx unguis ( d ’ Orbigny , 1835 ) : Distribution extension and new records for Brazil

central western Brazil. In fact, this is the only area in Brazil that was not sampled by Tillier (1981). Furthermore, Travassos (1928) used specimens of Omalonyx from Mato Grosso state as experimental hosts for a bird trematode, strongly suggesting that Omalonyx occurs in that area. The present investigation uses comparative morphology to establish the first record of O. unguis in western Brazil. The occurrence of the genus in this region is thus confirmed, and the known geographical distribution of the species is expanded. The material studied consists of slugs collected (permits granted by IBAMA [SISBIO] #12113-3) from four localities in western Brazil: Foz do Iguaçu, Paraná state; Campo Grande and Miranda, Mato Grosso do Sul state; and Poconé, Mato Grosso state. All samples were collected from aquatic vegetation on the margins of freshwater systems. One specimen from Miranda is shown in Figure 1. The animals were taken to the laboratory, where they were kept alive until sexual maturity was ascertained by the extrusion of eggs. Mature animals were relaxed overnight in water at 4°C and then killed by immersion in hot water (80°C) for 45 seconds. Shells were removed and stored in dry receptacles, and samples of foot tissue were frozen in an ultra-low temperature freezer (-80°C) for further molecular studies. Bodies were then preserved in RallietHenry solution (5% formaldehyde, 2% acetic acid, 0.6% sodium chloride). All specimens were deposited in the malacological collection of the Laboratório de Malacologia e Sistemática Molecular (LMSM) in the zoology department of the Universidade Federal de Minas Gerais, Brazil. Reproductive systems were dissected from the preserved bodies and compared with descriptions of anatomical details that are widely used to identify O. unguis (Hylton-Scott and Lapuente 1968; Arruda et al. 2006; Arruda and Thomé 2008) and other species of the genus (Hylton-Scott and Lapuente 1968; Hylton-Scott 1971; Tillier 1980; 1981). We examined the following Brazilian material: Paraná Omalonyx unguis (d’Orbigny, 1835) is the type species of the genus Omalonyx d’Orbigny, 1837, which comprises neotropical succineid slugs. Although this species has been reported from Brazil on different occasions (Moricand 1836; Hidalgo 1870; 1872; Lange de Morretes 1949; Salgado and Coelho 2003; Simone 2006), information from a recent study (Arruda and Thomé 2008) suggests that those reports may be incorrect. Tillier (1981) conducted an extensive taxonomic study of the genus using samples from most of the South American countries and the Lesser Antilles. In Brazil, he studied animals from the southern, southeastern, northeastern and northern regions, but did not include specimens from the central western region. Tillier (1981) established O. unguis as the senior synonym of most of the southern species of Omalonyx (O. convexus Martens, 1868; O. patera Doring, 1873; O. gallardoi Hylton-Scott and Lapuente, 1968, O. weyrauchi Hylton-Scott, 1970), which resulted in a distribution of O. unguis that included Argentina, Paraguay and the southern region of Brazil. Arruda and Thomé (2008) revalidated the species O. convexus and explained that all of the specimens identified as O. unguis by Tillier (1981) were, in fact, O. convexus, with the exception of the paratype from Paraguay (shell only). The map provided by Arruda and Thomé (2008) shows overlapping distributions of the two species in the Argentinean region of the Parana River Basin and adjacent localities in Uruguay. That map also shows that O. convexus extends to Rio Grande do Sul state in southern Brazil; while O. unguis extends to the Paraguay River sub-basin in Paraguay. This distributional pattern excluded Brazil from the range of O. unguis. Hylton-Scott and Lapuente (1968) also reported O. unguis in eight localities, most in Argentina and one in Paraguay. The previously known occurrences of O. unguis are summarized in Table 1. Although there are no consistent records of O. unguis occurrence in Brazil, there is no reason to doubt its occurrence in the upper Paraguay River sub-basin of Abstract: Omalonyx unguis was previously known to occur in Argentina, Paraguay and Uruguay. We report the first conclusive record of occurrence of this species in Brazil, based on specimens collected in three localities in the Paraguay River sub-basin (Mato Grosso do Sul state – Campo Grande and Miranda; Mato Grosso state – Poconé), and in the Brazilian margin of the Paraná River (Foz do Iguaçu, Paraná State). The species was identified by comparative morphology of the reproductive system, and a map that synthesizes the literature and reports new records is presented. 1 Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Parasitologia. Avenida Antônio Carlos 6627. CEP 31270901. Belo Horizonte, MG, Brasil. 2 Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Zoologia, Laboratório de Malacologia e Sistemática Molecular. Avenida Antônio Carlos 6627. CEP 31270-901. Belo Horizonte, MG, Brasil. * Corresponding author. E-mail: teofania.vidigal@gmail.com Daniel Coscarelli 1,2 and Teofânia H. D. A. Vidigal 2* Mollusca, Gastropoda, Succineidae, Omalonyx unguis (d’Orbigny, 1835): Distribution extension and new records for Brazil

central western Brazil.In fact, this is the only area in Brazil that was not sampled by Tillier (1981).Furthermore, Travassos (1928) used specimens of Omalonyx from Mato Grosso state as experimental hosts for a bird trematode, strongly suggesting that Omalonyx occurs in that area.
The present investigation uses comparative morphology to establish the first record of O. unguis in western Brazil.The occurrence of the genus in this region is thus confirmed, and the known geographical distribution of the species is expanded.
The material studied consists of slugs collected (permits granted by IBAMA [SISBIO] #12113-3) from four localities in western Brazil: Foz do Iguaçu, Paraná state; Campo Grande and Miranda, Mato Grosso do Sul state; and Poconé, Mato Grosso state.All samples were collected from aquatic vegetation on the margins of freshwater systems.One specimen from Miranda is shown in Figure 1.The animals were taken to the laboratory, where they were kept alive until sexual maturity was ascertained by the extrusion of eggs.Mature animals were relaxed overnight in water at 4°C and then killed by immersion in hot water (80°C) for 45 seconds.Shells were removed and stored in dry receptacles, and samples of foot tissue were frozen in an ultra-low temperature freezer (-80°C) for further molecular studies.Bodies were then preserved in Ralliet-Henry solution (5% formaldehyde, 2% acetic acid, 0.6% sodium chloride).All specimens were deposited in the malacological collection of the Laboratório de Malacologia e Sistemática Molecular (LMSM) in the zoology department of the Universidade Federal de Minas Gerais, Brazil.
Reproductive systems were dissected from the preserved bodies and compared with descriptions of anatomical details that are widely used to identify O. unguis (Hylton-Scott and Lapuente 1968;Arruda et al. 2006;Arruda and Thomé 2008) and other species of the genus (Hylton-Scott and Lapuente 1968;Hylton-Scott 1971;Tillier 1980;1981).
The taxonomic characters that we examined matched the diagnosis proposed by Arruda and Thomé (2008), confirming the species identification of the Brazilian specimens as O. unguis.That identification was also consistent with the taxonomic information provided by Hylton-Scott and Lapuente (1968) concerning the Argentinean populations of O. unguis.The reproductive system, which provides the anatomical features that allow specific identification, is shown in Figure 2. The presence of a serpent-like fold in the surface of the epiphallus (Figure 2D), is the most robust and evident character that is used for the diagnosis of this species.
The presence of O. unguis in the material that we examined confirms that the geographical distribution of this species encompasses two hydrological systems in Brazil.The first is the Paraguay River sub-basin, which drains the Pantanal region of western Brazil.The second is the Paraná River where it forms the border between Brazil and Paraguay.These new records extend the range of O. unguis northward, and the map in Figure 3 shows the new profile of its distribution.Mato Grosso do Sul Miranda LMSM 2705-08, 2739-42, 2769, 2780-81, 2788, 2795-99, 2898-99, 2900-08, 2911-13, 2917 36 Mato Grosso do Sul Previously known occurrences of Omalonyx unguis, based on reports in the literature.
That map also shows that O. convexus extends to Rio Grande do Sul state in southern Brazil; while O. unguis extends to the Paraguay River sub-basin in Paraguay.This distributional pattern excluded Brazil from the range of O. unguis.Hylton-Scott and Lapuente (1968) also reported O. unguis in eight localities, most in Argentina and one in Paraguay.The previously known occurrences of O. unguis are summarized in Table 1.Although there are no consistent records of O. unguis occurrence in Brazil, there is no reason to doubt its occurrence in the upper Paraguay River sub-basin of Coscarelli and Vidigal | New records of Omalonyx unguis for Brazil Check List | Volume 7 | Issue 4 | 2011 state -Foz do Iguaçu, Refúgio Ecológico Bella Vista, by the margins of the Itaipu Dam, Paraná River, 25°26'49" S, 54°32'58" W (LMSM 3260, 3269; Coscarelli, D. coll.);Mato Grosso do Sul state -Campo Grande, on the campus of the Universidade Federal do Mato Grosso do Sul, 20°30'19" S, 54°36'57" W (LMSM 2747; Coscarelli, D. coll.) and Miranda, Fazenda São Francisco, 20°05'56" S, 56°42'34" W (LMSM

Table 2 .
New records of Omalonyx unguis occurrence in Brazil based on recent field collections.LMSM= Laboratório de Malacologia e Sistemática Molecular, Zoology Department of the Universidade Federal de Minas Gerais, Brazil.