An Annotated Checklist of Monogeneans (Platyhelminthes, Monogenea) from Aquatic Vertebrates in Peru: A Review of Diversity, Hosts and Geographical Distribution.

Simple Summary: Simple Summary: Monogeneans are flatworm parasites that live principally in the gills of fish and sometimes infect other animals like amphibians, reptiles, and even mammals such as hippos. However, our understanding of these parasites in Peru is limited. To fill this gap, we compiled a detailed list of monogeneans found in Peru by studying the existing literature and examining specimens in collections. This list includes information about diversity, hosts, and geographical distribution. We reported 358 species of monogeneans, mostly infecting fish, with a few infecting amphibians. Most of these parasites live in fresh water, but some are found in marine environments. The most common families of monogeneans are Dactylogyridae and Diplectanidae. Some fish species harbor more parasites than others. However, many species have not been properly studied or collected, highlighting the need for further research to fully understand the diversity of monogeneans in Peruvian aquatic ecosystems. Monogeneans are flatworm parasites that infest fish gills primarily but can also infect various other vertebrates, including amphibians, aquatic reptiles, mammals like hippos, and occasionally invertebrates like copepods, isopods, and cephalopods. Despite their remarkable diversity, our knowledge of monogenean parasites in Peru remains significantly limited, resulting in substantial gaps in our comprehension of their taxonomic identities, host associations, and geographic distribution. To address these knowledge deficits, we present an extensively curated checklist of monogeneans associated with aquatic vertebrates in Peru. This comprehensive compilation is derived from meticulous literature surveys, the examination of specimens deposited in both international and national collections, and the inclusion of additional freshly collected specimens. The checklist offers a thorough repository of data encompassing the diversity, host associations, and geographical distribution of these parasites. Taxonomic discrepancies are addressed through a critical review of the existing literature, supplemented by the direct examination of specimens, including type or voucher specimens, deposited within scientific collections. Additionally, we provide data on the DNA sequences of individual taxa. The compiled list comprises records of 358 monogenean species, including 270 valid species and 88 taxa identified at the family or generic level, all reported across 145 host species in Peru. Predominantly, these parasitic species exhibit associations within fish, with 335 infecting teleosts and 20 affecting chondrichthyans. Three monogenean species have been documented as infecting amphibians, namely Mesopolystoma samiriensis, Polistoma sp. and Wetapolystoma almae. Among the monogeneans reported, 141 were found in marine environments and 214 in freshwater environments. The most diverse families were Dactylogyridae and Diplectanidae, comprising 217 and 24 species, respectively. The hosts that harbored the highest number of monogeneans were Pygocentrus nattereri (with 23 species), followed by Stellifer minor (13 spp.) and Triportheus angulatus (11 spp.). We detected many species that do not have any material deposited in a scientific collection due to the loss or deactivation of the collection. These findings represent only a fraction of the potential diversity, considering the wide variety of aquatic vertebrate hosts inhabiting the tropical and subtropical regions of Peru. [ABSTRACT FROM AUTHOR]