Annotated checklist of fish cestodes from South America

Abstract

An exhaustive literature search supplemented by a critical examination of records made it possible to present an annotated checklist of tapeworms (Cestoda) that, as adults or larvae (metacestodes), parasitize freshwater, brackish water and marine fishes, i.e. cartilaginous and bony fishes, in South America. The current knowledge of their species diversity, host associations and geographical distribution is reviewed. Taxonomic problems are discussed based on a critical evaluation of the literature and information on DNA sequences of individual taxa is provided to facilitate future taxonomic and phylogenetic studies. As expected, the current knowledge is quite uneven regarding the number of taxa and host-associations reported from the principal river basins and marine ecoregions. These differences may not only reflect the actual cestode richness but may also be due to the research effort that has been devoted to unravelling the diversity of these endoparasitic helminths in individual countries. A total of 297 valid species, 61 taxa identified to the generic level, in addition to unidentified cestodes, were recorded from 401 species of fish hosts. Among the recognized cestode orders, 13 have been recorded in South America, with the Onchoproteocephalidea displaying the highest species richness, representing c. 50% of all species diversity. The majority of records include teleost fish hosts (79%) that harbour larval and adult stages of cestodes, whereas stingrays (Myliobatiformes) exhibit the highest proportion of records (39%) among the elasmobranch hosts. Fish cestodes are ubiquitous in South America, being mostly recorded from the Warm Temperate Southeastern Pacific (WTSP; 31%) for marine hosts and the Amazon River basin (45%) for freshwater ones. The following problems were detected during the compilation of literary data: (i) unreliability of many records; (ii) poor taxonomic resolution, i.e. identification made only to the genus or even family level; (iii) doubtful host identification; Alves et al. / ZooKeys 650: 1-205 (2017) 2 and (iv) the absence of voucher specimens that would enable us to verify identification. It is thus strongly recommended to always deposit representative specimens in any type of studies, including faunal surveys and ecological studies. An analysis of the proportion of three basic types of studies, i.e. surveys, taxonomic and ecological papers, has shown a considerable increase of ecological studies over the last decade.

Marine invertebrate biodiversity from the Argentine Sea, South Western Atlantic

“…This inverse tendency between biodiversity and latitude seems to be balanced by a higher biomass and endemism at higher latitudes (Boltovskoy et al 2005). In the last years, some studies have been done in order to document these patterns in marine invertebrates from the South Western Atlantic (Astorga et al 2003, Bertness et al 2006, Diez 2006, López Gappa et al 2006, López Gappa and Sueiro 2006, Carranza et al 2009, Griffiths et al 2009, Scarabino et al 2016, Zelaya 2016, Alves et al 2017, among others). Also, some international initiatives as NaGISA (Census of Marine Life), or SARCE (South American Research Group on Coastal Ecosystems), contribute to the knowledge of the coastal marine biodiversity.…”

Integrative taxonomy reveals hidden cestode diversity in Pimelodus catfishes in the Neotropics

“…Catfishes represent c . 80% of the known hosts for proteocephalids in South America with certain species of large pimelodids harbouring up to nine species of cestodes in their intestines (Alves, de Chambrier, Luque, Scholz, 2017).…”

Helminth parasites of alien freshwater fishes in Patagonia (Argentina)

“…This invasive cestode is originally from Asia, and has been co–introduced worldwide, mainly with carp. In South America this parasite was recorded in 5 freshwater fish species from Brazil ( Alves et al, 2017 ). Asian carp have been reported in lakes from Buenos Aires Province since 1925 ( Rosso, 2006 ), but reached Patagonian environments only recently, about 25 years ago ( Peréz and López Cazorla, 2008 ).…”

“…The checklist follows the classification of Boeger and Kritsky (1993a , b) , Thatcher (2006) , and Cohen et al (2013) for monogeneans, Gibson et al (2002) , Jones et al (2005) , and Bray et al (2008) for digeneans, Khalil et al (1994) and Alves et al (2017) for cestodes, Moravec (1998) , Anderson et al (2009) , and Gibbons (2010) for nematodes, Amin (2013) for Acanthocephalans, and Froese and Pauly (2017) for fishes. River basins, followed by localities, are presented in latitudinal disposition between brackets, and in cases where localities belong to the same river basin, from upper to lower waters (see Supplementary data ).…”