New Species of Urocleidoides (Dactylogyridae) from Hoplias malabaricus (Osteichthyes: Erithrynidae) from the Amazonas River, Peru.

INTRODUCTION: Parasitological studies in Hoplias malabaricus (Bloch), with emphasis on the identification of monopisthocotyls have reported 17 species, but only one has been documented from Peru. Thus, the main objective of the present study was to record the dactylogyrids that parasitize H. malabaricus acquired in the Peruvian Amazon. MATERIAL AND METHODS: Twenty H. malabaricus were collected in Zungaro Cocha market, in Iquitos, Loreto, Peru. Parasites were removed from gills or sediment with dissection needles, and specimens were cleared in Hoyer's medium to study sclerotized structures. RESULTS: Two new species were registered; Urocleidoides fasacoi n. sp. that resembles U. vanini Santos-Neto & Domingues, 2023 in the morphology of the MCO, but it differs mainly by the number of rings (five and a half vs. three and a half), additionally in presence of a sclerotized vaginal sclerite and Urocleidoides chuquipiondoi n. sp. Urocleidoides chuquipiondoi n. sp. resembles U. macrosoma Santos-Neto & Domingues, 2023 in the morphology of the MCO that is a sclerotized tube with one counterclockwise ring, but it differs mainly by the absence of vaginal sclerite, additionally presents longer anchors with straight point. CONCLUSIONS: The discovery and description of two new species of Urocleidoides increases the number of valid species to 87, highlighting the first two species of this genus described from Peruvian Amazon.