ABSTRACT
A new species of nematode, Pterygodermatites (Paucipectines) sinopiensis n. sp. is described based on specimens recovered from the intestine of the white-bellied woolly mice opossum, Marmosa constantiae, trapped in the municipality of Sinop, Mato Grosso state, Brazil. The genus Pterygodermatites has 21 species described in mammals worldwide, and to date, only two species have been described for marsupials in Brazil. The new species is characterized by the presence of 23 small denticles and by the presence of 38-40 and 65 pairs of the cuticular processes in male and female species, respectively. Additionally, male species possess three ventral precloacal fans, and in female species, the cuticular processes are divided into 41 pairs of comb-like and 24 pairs of spine-like processes; the vulva opens approximately in pair 41. This study describes the parasite species fifth of marsupials in the Neotropical region.
ABSTRACT
Phylogenetically or taxonomically related hosts may harbour similar parasite communities due to phylogenetic conservatism. In addition, host attributes may favour their exposure to parasites. This study aimed to characterize the helminth fauna of sigmodontine rodents in an Atlantic Forest area in northeastern Brazil and determine the pattern of the helminth metacommunity structure. The influence of host attributes and host taxonomy on the metacommunity structure was also investigated. The most abundant helminth species were Raillietina sp. and Hassalstrongylus lauroi. Euryoryzomys russatus was the most infected host species for helminth parasites, as approximately 81% (35/43) of the animals were infected by at least one helminth species. The helminth metacommunity structure was coherent at both the infracommunity and the component community scales, indicating that species responded to the same environmental gradient. A quasi-Clementsian pattern was observed for the infracommunities, indicating the occurrence of compartments of parasite species that were substituted along the environmental gradient, which was formed by host individuals. A quasi-Gleasonian pattern was found at the component community scale, showing random boundary clumping, which is consistent with the individualistic responses of parasite species to each host species. These patterns corroborated the high values of beta-diversity observed, indicating high species turnover among communities at both scales. Host taxonomic distance was the most important variable explaining the patterns of the helminth metacommunity structure.
ABSTRACT
A new species of Trichostrongyloidea (Nematoda: Heligmonellidae), Hassalstrongylus lauroi n. sp., is described from specimens collected from the small intestine of the rodent Hylaeamys seuanezi in the Atlantic Forest of northeastern Brazil (Igrapiúna, state of Bahia). The genus Hassalstrongylus includes 17 species, which parasitize rodents occurring in the Neotropical and Nearctic regions. It differs from the genus Stilestrongylus through its smaller number of ridges in the synlophe and through the size of the genital cone. The main taxonomic characteristics of this new species are the subsymmetrical caudal bursa of type 2-2-1, ray 8 branching out at the base of the dorsal trunk, right lobe smaller than the left, and rays 4 and 5 of robust nature. In addition, the ornamental ray 5 and the robustness of ray 4 on the male caudal bursa, along with the modification of the ridges of the posterior end of the female, allow us to consider the specimens found to be a new species.
Subject(s)
Rodent Diseases , Trichostrongyloidea , Trichostrongyloidiasis , Animals , Brazil , Female , Forests , Male , Sigmodontinae , Trichostrongyloidiasis/veterinaryABSTRACT
The ecology of host-parasite interactions can be studied in the infracommunity and component community scales, which may show different patterns in species distributions, interacting and affecting each other on a regional scale. Few studies have been carried out concerning the structure and variation of the helminth communities of wild rodents in Brazil. The rodent Necromys lasiurus is typical from the mammalian fauna of the Cerrado biome; however, the environmental disturbances are making this species occur in rural areas and in other biomes where it may act as host/reservoir of many diseases. This study aimed to describe the composition and structure of the helminth metacommunity in the rodent N. lasiurus in the Brazilian Cerrado, Uberlândia, State of Minas Gerais, using the analysis of metacommunity structure. Rodents were sampled in 3 habitat types: borders of soybean and corn plantations, pasturelands, and preserved areas of Cerrado borders. Adult helminths of 8 species were found in the gastrointestinal tract: Protospirura numidica criceticola, Physaloptera sp., Pterygodermatites ( Paucipectines) zygodontomis (Spirurida), Stilestrongylus freitasi (Rhabditida), Trichuris navonae (Trichurida) and Syphacia ( Syphacia) alata (Oxiurida) of the Phylum Nematoda; Rodentolepis akodontis (Cyclophyllidea) of the Phylum Platyhelminthes; and Moniliformis sp. (Moniliformida) of the Phylum Acanthocephala. Season and the kind of land use favored some helminths species in this rodent, especially in the plantation area, although diversity was not largely influenced by the land use. Plantation areas could provide an increase in the host abundance and the occurrence of other rodent species, favoring a higher rate of parasite exchange among different hosts. A checkerboard structure of metacommunity was found on the infracommunity scale, which suggests the existence of interspecific competition. A quasi-nested structure of metacommunity was observed on the component community scale showing that most species were influenced by the same environmental gradient and that the species-poor communities were subsets of species-rich communities. Syphacia alata, P. zygodontomis, S. freitasi, and R. akodontis were dominant species in all habitats and represented the core-species in the metacommunity.
