New Host Records of Brazilian Pentastomid Species

Pentastomida is a taxon of parasitic organisms infecting generally the respiratory system of vertebrates, mainly reptiles. Although this taxon is very important for understanding the phylogeny of the Metazoa, it has received little attention. In Brazil, there are few collections that include species of pentastomids, that is, only the Helminthological Collection of the Oswaldo Cruz Institute (CHIOC), the Invertebrate Collection of the Zoology Laboratory of the Regional University of Cariri (LAZ-URCA) and the Helminthological Collection of the Botucatu Institute of Biosciences (CHIBB). The present study describes the species of pentastomids deposited in CHIBB. When found, the pentastomids were mounted on slides in Hoyer's medium and identified. Four species of pentastomids were recognised and three others were identified at the genus level, while four new hosts for the species of pentastomids were recorded. Novos registros de hospedeiros para espécies de pentastomídeos do Brasil Resumo Pentastomida é um táxon de organismos parasitas obrigatórios de sistema respiratório de vertebrados, principalmente répteis. Embora esse táxon seja muito importante para a compreensão da filogenia dos Metazoa, tem recebido pouca atenção. No Brasil, existem poucas coleções que abrigam espécies de pentastomídeos, quais sejam: a Coleção Helmintológica do Instituto Oswaldo Cruz (CHIOC), a Coleção de Invertebrados do Laboratório de Zoologia da Universidade Regional do Cariri (LAZ-URCA) e a Coleção Helmintológica do Laboratório de Parasitologia de Animais Silvestres (LAPAS). O presente trabalho descreve as espécies de pentastomídeos depositados na Coleção Helmintológia do LAPAS. O trato respiratório e as cavidades do corpo dos répteis foram removidos e analisados sob Microscópio Esteroscópico; quando encontrados os pentastomídeos, foram montados slides em meio Hoyer e identificados. Foram identificadas quatro espécies e outras três ficaram identificadas no nível de gênero, tendo sido registrados quatro novos hospedeiros para as espécies de pentastomídeos.

The aim of the present work was to enrich our knowledge of the biology of pentastomids by analysing the specimens and their hosts deposited in the Helminthological Collection of the Botucatu Biosciences Institute (CHIBB), located in the Laboratory of the Parasitology of Wild Animals (LAPAS) of the Universidade Estadual de São Paulo (UNESP).

Material and Methods
The respiratory tracts and body cavities of the reptiles were removed and the presence of pentastomids determined by examination under a stereomicroscope.All pentastomids found were cleared in Hoyer's medium and subsequently mounted on slides.Identifications were based on the dimensions of the hooks and copulatory spicules of the males that were measured using a microscope equipped with an ocular micrometer.
Sebekia oxycephala has already been reported as a parasite of the following vertebrates: fish species Pseudoplatystoma fasciatum (Linnaeus, 1766), Pygocentrus piraya (Müller & Troschel, 1848) (Almeida & Christoffersen, 2002;Sambon, 1922;Rego, 1984).In the crocodilian C. yacare, the cycle of S. oxycephala was observed for the first time, where larvae of S. oxycephala were found in the stomach and intestine and adult parasites in the lung.Sebekia oxycephala utilizes fish as an intermediate host and completes its cycle in C. yacare when it eats infected fish.Cayman yacare is distributed geographically in the central part of South America, where it is found in the north of Argentina, southern Bolivia, Brazilian Pantanal and rivers of Paraguay.It feeds on aquatic invertebrates such as mollusks and crustaceans and vertebrates (fish and snakes) (Reptile Database, 2010).
The parasite R. furcocerca is a typical parasite of snakes, with a Neotropical distribution.Besides Crotalus durissus (Linnaeus, 1758), this pentastomid species was recorded in various species of snakes: Boa constrictor, Coluber lichtensteinii (Raddi, 1820), Drymarcon corais (Boie, 1827), Xenodon merremii (Wagler, 1824) and Lachesis sp.(Motta, 1963;Rego, 1983).Thamnodynastes chaquensis which represents a new host for R. furcocerca, occurs in the provinces of the Chaco, where there are reports of this species in Argentina, Paraguay, Uruguay and Brazilian Pantanal.T. chaquensis is a nocturnal snake which is abundant in the Brazilian Pantanal, where it feeds mainly on amphibians and small rodents (Franco & Ferreira, 2002).
Raillietiella sp. 1 found in the lung of B. mattogrossensis differs from R. furcocerca because the male of this species is larger than the female, but its identification at the species level was not possible due to the lack of a male in the host analysed.B. mattogrossensis occurs in Brazil (Amazonas, Goias, Mato Grosso do Sul, Rondônia, São Paulo and Tocantins), Bolivia, Paraguay and Argentina.The diet of this snake consists of anuran amphibians, small mammals, lizards, snakes and centipedes (Monteiro et al., 2006).
The specimen Raillietiella sp.2 found in Liophis poecilogyrus (Wied-Neuwied, 1825) constituted the first report of infection by pentastomids in this species of snake.The identification of the parasite at the species level was not possible due to the lack of a male.The snake L. poecilogyrus is a species with wide geographic distribution, occurring from the eastern part of Guiana to southeastern Venezuela, advancing in a south-to-southeast direction down to Bolivia and Paraguay, also reaching the Pantanal and continuing down to the Argentinian Pampas and Chaco (Reptile Database, 2011); it feeds mainly on amphibians, particularly members of the families Bufonidae and Hylidae (Pinto & Fernandes, 2004).
Although important studies on pentastomids have been published in recent years, knowledge of these parasites in Brazil still needs to be substantially extended, since the majority of the species of Squamata and vertebrates in general that are definitive hosts of these parasites still lack studies aimed at learning about the fauna of associated pentastomids and their ecological and evolutionary relations with their vertebrate hosts.

Table 1 .
Records of pentastomids deposited in the Helminthological Collection of the Botucatu Biosciences Institute (CHIBB).
*Numbers in the last column are the accession numbers of voucher species in CHIBB -Helminthological Collection of the Department of Parasitology, Institute of Biosciences, Universidade Estadual Paulista.