Helminth parasites of South American fishes: current status and characterization as a model for studies of biodiversity

Abstract

The South American subcontinent supports one of the world's most diverse and commercially very important ichthyofauna. In this context, the study of South American fish parasites is of increased relevance in understanding their key roles in ecosystems, regulating the abundance or density of host populations, stabilizing food webs and structuring host communities. It is hard to estimate the number of fish parasites in South America. The number of fish species studied for parasites is still low (less than 10%), although the total number of host-parasite associations (HPAs) found in the present study was 3971. Monogeneans, with 835 species (1123 HPAs, 28.5%), and trematodes, with 662 species (1127 HPAs, 30.9%), are the more diverse groups. Data gathered from the literature are useful to roughly estimate species richness of helminths from South American fish, even though there are some associated problems: the reliability of information depends on accurate species identification; the lack of knowledge about life cycles; the increasing number of discoveries of cryptic species and the geographically biased number of studies. Therefore, the closest true estimations of species diversity and distribution will rely on further studies combining both molecular and morphological approaches with ecological data such as host specificity, geographical distribution and life-cycle data. Research on biodiversity of fish parasites in South America is influenced by problems such as funding, taxonomic impediments and dispersion of research groups. Increasing collaboration, interchange and research networks in the context of globalization will enable a promising future for fish parasitology in South America.

Metazoan fauna parasitizing Peckoltia braueri and Pterygoplichthys pardalis (Loricariidae) catfishes from the northeastern Brazilian Amazon

“…Monogenoidea is the most diverse taxa in fish from South America, with 835 species reported from hosts of different countries, most of them from freshwater habitats (Luque et al 2016). Thirteen genera of monogeneans can be found parasitizing several species of Loricariidae, but Unilatus Mizelle & Kritsky, 1967 andTrinigyrus Hanek, Molnar &Fernando, 1974 (Dactylogyridae) are the most frequently encountered in these hosts (Cohen et al 2013).…”

“…Cestoda represents the third species-rich group of helminths in South America, with 460 species found in different countries (Luque et al 2016). Proteocephalus species are the most frequent cestodes in Siluriformes from South America (Rego et al 1999;Chambrier et al 2006).…”

Metazoan Parasites of <i>Geophagus proximus</i>, a Cichlidae Fish from the Eastern Amazon (Brazil)

“…Therefore, the fact that G. proximus is a small cichlid favors its predation. Raphidascaris (S.) lanfrediae is a nematode that has also been reported parasitizing Geophagus argyrosticus Kullander, 1991 Digenea are widely geographically distributed, and in South America are known 662 species infecting diverse fish species [34], as they parasite different species of vertebrates, especially fish and piscivorous birds. The life cycle of these endohelminths usually includes three hosts: mollusks, fish and piscivorous birds [35] [36].…”

Parasites of ornamental fish commercialized in Macapá, Amapá State (Brazil)

“…In Brazil, over 60 species of acanthocephalans have been described in freshwater fish, including ornamental fish (LUQUE et al, 2017). Acanthocephalans of genus Echinorhynchus Zoega in Müller, 1776 was found only in the intestine of C. ephippifer at low infection levels.…”