Diversity of Monopisthocotyla from the gills of Hoplerythrinus unitaeniatus (Spix & Agassiz) (Characiformes: Erythrinidae) in the Peruvian Amazon, including the description of a new species of Anacanthorus Mizelle & Price, 1965 (Dactylogyridea: Ancyrocephalidae)
摘要
Species of Monopisthocotyla (Dactylogyridae) are common gill parasites of Neotropical freshwater fishes; however, their diversity in the Peruvian Amazon remains poorly documented, particularly in erythrinid hosts such as Hoplerythrinus unitaeniatus (Spix & Agassiz). Among these, species of Anacanthorus Mizelle & Price, 1965 are especially diverse and frequently reported. This study aimed to document the species of Monopisthocotyla associated with the gills of H. unitaeniatus in the Peruvian Amazon, including the description of a new species of the genus Anacanthorus. Twenty specimens of H. unitaeniatus were examined, and the parasites were collected and analyzed using standard morphological methods. Four species of Anacanthorus were recorded: A. siphonocommus Neto, Muriel-Cunha & Domingues, 2019, A. cururutuiensis Neto, Muriel-Cunha & Domingues, 2019, and A. circumspatulatus Neto, Muriel-Cunha & Domingues, 2019, as well as a new species described here as Anacanthorus arequipensis n. sp. One species of Whittingtonocotyle, W. caetei Neto, Rodrigues & Domingues, 2015, was also recorded. In addition, Anacanthorus sp. was observed, which was not formally described due to the availability of only one specimen. Anacanthorus arequipensis n. sp. is distinguished by a robust, slightly curved, tubular male copulatory organ with a distinctive distal annular structure that partially surrounds the tip of the cirrus, and the absence of an accessory piece. This study increases the number of known Anacanthorus species in H. unitaeniatus from five to six and represents the first description of a new species of Monopisthocotyla in H. unitaeniatus from Peru, highlighting the underestimated diversity of this group of parasites in the Peruvian Amazon.