Gill infection in Macrodon ancylodon and Nebris microps caused by Lernanthropus sp. (Copepoda: Lernantropidae) in the Brazilian Amazon

The research reports the occurrence and morphologically describes Lernanthropus sp. in the gills of sciaenid fish Macrodon ancylodon and Nebris microps. Specimens of the species were collected and examined. Ectoparasitic copepods with morphological characteristics inherent to the genus Lernanthropus were observed on the gills of the hosts and exhibited the same parasitic prevalence (25%). The copepod in M. ancylodon was male and did not exhibit a sac-like projection with eggs, with poorly developed antennae in the anterior region, a body measuring 4.33 mm in length, and a head distinct from the trunk measuring 0.96 mm (length) x 1.15 mm (width). While in N. micros, it was female, with a very evident sacuolar projection, with more developed and larger antennae than the specimen obtained in M. ancylodon, the anterior part of the trunk (2.1 mm) narrower than the posterior (3.2 mm) and a continuous plate to the trunk in an oval circular shape, with a sacuolar projection (4 mm). It should be noted that until now, there has been no report of the occurrence of this genus in the hosts studied in the state of Pará, which makes this work an important record for the knowledge of the ichthyosanitary status in this region.