This study provides an updated list of parasite species and their respective hosts in the upper Paraná River floodplain. The list of parasites is structured by phylum, class, order and family, followed by a record of each host species. A total of 315 taxa of parasites were reported, of which 201 were identified at the species level. These 201 species comprise 3 Flagellata, 3 Myxozoa, 50 Monogenea, 43 Digenea, 40 Cestoda, 41 Nematoda, 8 Acanthocephala, 6 Copepoda, 5 Branchiura and 2 Pentastomida, arranged in 84 host fish species. This work carried out in the floodplain of the upper Paraná River contributes to the listing of parasite species and host interactions of the local ichthyofauna. Little is known about these communities and its riches are underestimated due to the high density of fish found in this region, highlighting the importance of conducting studies on the local fauna.

No abstract

Centrocestus formosanus is a digenean parasite fi rst described from Asia, which parasitizes Melanoides tuberculata (Gastropoda: Thiaridae) at the fi rst intermediate stage, and different fi sh species as second intermediate host. C. formosanus was previously recorded in Brazilian states, but never before in the southern region of this country. Recording and identifi cation of digenean species through morphological identifi cation is a taxonomic challenge. In light of this, we use an integrative taxonomic approach to report the occurrence of cercariae and metacercariae of C. formosanus in molluscs and fi sh, respectively, in an urban park located in southern Brazil. Specimens of M. tuberculata and the fi shes Poecilia reticulata and Xiphophorus sp. (Poeciliidae) were collected for screening for parasites and molecular analyses using partial fragments of the 28S rDNA gene. The identifi cation of C. formosanus obtained from molluscs and fi sh specimens permitted us to partially solve the life cycle of this parasite for the fi rst time in the studied environment, demonstrating the necessity of monitoring and controlling molluscs populations. Nevertheless, our results will support future studies aiming to elucidate the life-cycle of C. formosanus in this region, since all sampled hosts' species are invasive in this environment.

This study aimed to enhance our understanding in monogenoid evolution by using morphological and molecular data to determine kinship relationships between species and changes in morphological structures over time. We focused on variations in characteristics among the organisms of the family Gyrodactylidae, concentrating on the phylogenetic position of Polyclithrum with other genera in the family. We collected specimens of Polyclithrum from the striped mullet, Mugil cephalus and Swingleus, and Fundulotrema specimens from mummichog Fundulus heteroclitus in estuarine systems of South Carolina, United States. In addition, we analyzed them and other genera (including e.g., Mormyrogyrodactylus, Gyrodactyloides, and Macrogyrodactylus) using both morphological and molecular (18S rDNA) approaches. We performed phylogenetic trees based on Maximum Parsymony, Maximum Likelihood and Bayesian Inference, and constructed a character morphological matrix by Parsimony Reconstruction of Ancestral Character States method. Our results suggest a homoplastic origin with evolutionary convergences in characters, revealing that there is inconsistency between our data and previously published works based solely on morphological structures of the group. The homoplasy scenario found in Gyrodactylidae can be a result of the limited set of putative homologous morphological features. However, differences between the phylogenies based on morphology and those based on molecular data may arise from both databases. While morphology remains essential in understanding the evolution of this group, molecular data, otherwise, provide a less biased source of information for constructing phylogenetic hypotheses. Combining these data facilitates a better comprehension of the homologous status of morphological features and to understand Gyrodactylidae evolutionary history.