RESUMO
PURPOSE: The goal of this work was to increase the knowledge of the parasitic helminths of the Crane hawk, Geranospiza caerulescens. METHODS: Two specimens of the Crane hawk were captured in Formosa province, Argentina, their viscera were preserved in 10% formalin and examined in the laboratory. RESULTS: Helminthological analysis revealed the presence of six helminth taxa (one Trematoda, four Nematoda, and one Acanthocephala). The morphometric study of these helminths and its comparison with previous reports, allowed us to describe a new species of Parastrigea (Digenea: Strigeidae) and report new host-parasite associations and geographical records. Parastrigea labiata n. sp. is mainly characterized by having forebody not divided and two long trumpet-shaped projections of dorsal lip, which emerge through the opening. Five taxa, previously known, Synhimantus (Dispharynx) resticula, Synhimantus (Synhimantus) rectus, Microtetrameres sp., Porrocaecum sp. and Centrorhynchus sp. are briefly described. CONCLUSIONS: Previous parasitological studies on G. caerulescens were carried out on material collected between 1817 and 1955, and seven species of helminths were reported. In this study, the six taxa of helminths found constitute new host records, which shows the importance of contemporary studies about this host. All helminths found have heteroxenous life cycles and birds are infected by trophic transmission. Crane hawk's diet includes small vertebrates and to a lesser extent large arthropods. The finding of five helminth species that use invertebrates as intermediate hosts could indicate an important consumption of invertebrates. This research expands the helminthological inventory of Argentinean birds and the knowledge of the helminths of G. caerulescens.
RESUMO
Trematodes belonging to the superfamily Diplostomoidea have complex life cycles involving birds, mammals and reptiles as definitive hosts, and gastropods and different groups of invertebrates and vertebrates as intermediate hosts. Molecular studies of these parasites are numerous, but data from larval stages in molluscs remain scarce, particularly in South America. The present study focused mainly on five morphotypes of longifurcate cercariae found in Biomphalaria straminea (Dunker, 1848) from Belo Horizonte, Minas Gerais, Brazil, collected between 2009 and 2017. In each morphotype, nuclear internal transcribed spacer (ITS1-5.8S ITS-2) rDNA and mitochondrial cytochrome c oxidase 1 (COI) genes were sequenced. Laboratory-reared fish, Poecilia reticulata Peters, 1859 or snails, Biomphalaria glabrata (Say, 1818) were exposed to cercariae to obtain metacercariae. The morphology of cercariae, experimentally obtained metacercariae, and phylogenetic analyses led to the identification of three species of Diplostomidae [Austrodiplostomum compactum (Lutz, 1928), Crassiphialinae gen. sp. and Hysteromorpha sp.] and two species of Strigeidae (Cotylurus sp., Apharyngostrigea sp.). Previously published sequences allowed species-level identification for only A. compactum, although provisional identifications were possible in two cases. First, the COI from cercariae of Apharyngostrigea sp. in Brazil matched those of metacercariae from naturally infected Cnesterodon decemmaculatus (Jenyns, 1842) in Argentina; although a positive identification is not possible, the material presents morphological similarities with larval stages previously described for A. simplex. Secondly, Cotylurus sp. resembles C. lutzi. Our analysis of previously published COI sequences suggests that Cotylurus cornutus (Rudolphi, 1808) has a Holarctic distribution. Both the morphology of experimentally obtained metacercariae and COI sequences indicate that Hysteromorpha sp. in Brazil is distinct from congeners in North America [Hysteromorpha corti (Hughes, 1929)] and Europe [Hysteromorpha triloba (Rudolphi, 1819)].
Assuntos
Biomphalaria/parasitologia , Cercárias/anatomia & histologia , Trematódeos/anatomia & histologia , Infecções por Trematódeos/parasitologia , Animais , Brasil , Feminino , Masculino , Trematódeos/classificação , Trematódeos/genéticaRESUMO
A new strigeid digenean, Strigea inflecta sp. nov., is described from the small intestine of the Red-legged Seriema, Cariama cristata (L.) (Gruiformes, Cariamidae) from Formosa Province, Argentina. This species is characterized by having a body plump, a cup-shaped forebody with a large opening, a sacciform hindbody, without a neck region and strongly curved dorsally, a poorly delimited copulatory bursa, wider than longer, a shallow and asymmetrical genital atrium, and a genital cone well delimited from body parenchyma, strongly muscular, inclined towards the surface ventral of the body. Another digenean species collected from Red-legged Seriema, Brachylaima yupanquii Freitas, Kohn et Ibáñez, 1967 (Brachylaimidae) is described with the addition of new morphological characters and morphometrical data. This species is reported for the first time in Argentina and C. cristata represents a new host record.