Assessing the role of taxonomic impediment in the knowledge on geographic distribution of Physidae (Gastropoda: Hygrophila) in South America, using an intensive-data approach.

There is a marked disparity in the state of knowledge of Holartic x Neotropical species of the freshwater snail family Physidae; the incipiency of data on Neotropical physids reflecting the lower number of dedicated specialists. The gaps in the knowledge on Neotropical physids have led to historical uncertainty about species validity. Revisiting the species is essential to reduce taxonomic impediment and delineating their probable distribution is the first step to attain this purpose. We aimed at critically analyze occurrence records of South American physids, compiled through an intensive search in the literature, biodiversity and molecular databases. We present a provisional characterization of the distribution of this family in South America, considering the probable versus the poorly documented distribution of the species. The critical underrepresentation of South American physids in collections, molecular databases and literature reinforces the role of taxonomic impediment in delaying the advance of the knowledge on species diversity. Malacological collections represented the main source of records, evidencing the relevance of unpublished data associated to specimens to assess distributional information on neglected groups. As most of the species are represented by shells, the reassessment of species identity and distribution must be done, using molecular and anatomical criteria for species delimitation.

High infestation and phylogenetic position of Epistylis sp. (Ciliophora, Peritrichia) on Aegla serrana Buckup & Rossi (Crustacea, Anomura) from southern Brazil.

High infestations of epibiont ciliates on vertebrates or invertebrates are normally related to aquaculture tanks or similar environments, and the importance of this relationship in natural habitats is often disregarded. Here, we describe the first record of high infestation of ciliates on Aegla serrana in South America and conduct a brief morphological and phylogenetic characterization of these ciliates. Our findings confirm that cases of high infestation of ciliates on metazoans can indeed occur in natural environments.

First record of Trypanosoma (Ornithotrypanum) infecting Neotropical birds.

Parasites play a pivotal role in ecosystem health, influencing human and zoonotic diseases, as well as biodiversity preservation. The genus Trypanosoma comprises approximately 500 species mostly found in wildlife animals. This study focuses on identifying trypanosomes found in the white-necked thrush (Turdus albicollis) and the yellow-legged thrush (Turdus flavipes) in the Neotropics. First, we demonstrate the utility of an 18S rDNA sequence-structure phylogeny as an alternative method for trypanosome classification, especially when gGAPDH sequences are unavailable. Subsequently, the sequence-structure phylogeny is employed to classify new trypanosome sequences discovered in wild birds, placing them within the Ornithotrypanum subgenus. This marks the first identification of Ornithotrypanum in Neotropical birds, contributing to the understanding of the distribution and ecological adaptation of avian trypanosomes. Beyond taxonomy, this study broadens our comprehension of the ecological implications of avian trypanosomes in the Neotropics, emphasizing the need for continued research in this field. These findings underscore the importance of alternative classification methods, which are essential to unravel the complex interactions between parasites, wildlife hosts, and their ecosystems.

Molecular diversity and coalescent species delimitation of avian haemosporidian parasites in an endemic bird species of South America.

Haemoproteus spp. and Plasmodium spp. are blood parasites that occur in birds worldwide. Identifying the species within this group is complex, especially in wild birds that present low parasitemia when captured, making morphological identification very difficult. Thus, the use of alternative tools to identify species may be useful in the elucidation of the distribution of parasites that circulate in bird populations. The objectives of this study were to determine the prevalence and parasitemia of the genera Plasmodium and Haemoproteus in Tachyphonus coronatus in the Atlantic Forest, Brazil, and to evaluate the molecular diversity, geographic distribution, and specificity of these parasites based on coalescent species delimitation methods. Microscopic analysis, PCR, cyt b gene sequencing, phylogenetic analysis and coalescent species delimitation using single-locus algorithms were performed (Poisson tree process (PTP) and multi-rate Poisson tree process (MPTP) methods). The analyses were performed in 117 avian host individuals. The prevalence was 55.5% for Plasmodium and 1.7% for Haemoproteus, with a mean parasitemia of 0.06%. Twenty-five Plasmodium and two Haemoproteus lineages were recovered. The MPTP method recovered seven different evolutionarily significant units (ESUs) of Plasmodium and one of Haemoproteus, whereas PTP presented fourteen ESUs of Plasmodium and one of Haemoproteus. The MPTP was more consistent with current taxonomy, while PTP overestimated the number of lineages. These ESUs are widely distributed and have already been found in 22 orders of birds that, all together, inhabit every continent, except Antarctica. The computational methods of species delimitation proved to be effective in cases where the classification of Haemosporida based just on morphology is insufficient.

Molecular Phylogeny of the Family Ophryscolecidae (Ciliophora, Litostomatea) Inferred from 18S rDNA Sequences.

The 18S rDNA was used to infer oral ciliature patterns of evolution within the family Ophryoscolecidae, with the addition of five new sequences of ciliates from the genus Ostracodinium. Our data confirmed the monophyly of the subfamilies Entodiniinae and Ophryoscolecinae, but more analysis would be required for the definition of the status of the subfamily Diplodiniinae. The oral infraciliature patterns reflect evolutionary divergence in the family Ophryscolecidae, observing monophyly on Entodinium-type, Diplodinium-type, Ostracodinium-type, Epidinium-type, and Ophryoscolex-type. The ancestral infraciliature of Entodinium-type cannot be proven, however, the position of Entodinium-type showed closer of Diplodinium-type than Ophryoscolex-type, corroborating previous studies using morphological characters. The observed inconsistencies reflect the need to increase the number of 18S rDNA sequences to family Ophryoscolecidae and investigate the evolution of this group using other molecular markers.