Dactylogyrids (Monogenoidea: Polyonchoinea) parasitising the gills of snappers (Perciformes: Lutjanidae): Species of Euryhaliotrema Kritsky & Boeger, 2002 from the golden snapper Lutjanus johnii (Bloch) off northern Australia, with a redescription of Euryhaliotrema johni (Tripathi, 1959) and descriptions of two new species

Abstract

Three species of Euryhaliotrema Kritsky & Boeger, 2002 (Monogenoidea: Dactylogyridae) were collected from the gills of four golden snapper Lutjanus johnii (Bloch) (Lutjanidae) from the marine and brackish waters off Darwin, Northern Territory, Australia. Type-specimens of Ancyrocephalus johni Tripathi, 1959 apparently have not survived and the possibility existed that the species was based on specimens representing more than one species. Euryhaliotrema johni (Tripathi, 1959) (sensu Young, 1968) was redescribed and determined to most likely represent A. johni, originally described from the River Hooghly, Diamond Harbour, India. Two new species were described. Euryhaliotrema longibaculoides n. sp. was most similar to Euryhaliotrema longibaculum (Zhukov, 1976) Kritsky & Boeger, 2002 from Lutjanus spp. from the western Atlantic Ocean. It differed from E. longibaculum by having a male copulatory organ (MCO) with an elongate comparatively delicate shaft and a bulbous base (MCO U- or J-shaped with funnel-shaped base in E. longibaculum). Based on the comparative morphology of the haptoral sclerites, Euryhaliotrema lisae n. sp. was most similar to Euryhaliotrema cryptophallus Kritsky & Yang, 2012 from the gills of the mangrove red snapper Lutjanus argentimaculatus (Forsskål) from the South China Sea. Euryhaliotrema lisae differed from E. cryptophallus by having a copulatory complex with an obvious weakly sclerotised J-shaped MCO (MCO cryptic, delicate, and with a shaft comprising about one counterclockwise ring in E. cryptophallus).

Two new species of Euryhaliotrema Kritsky et Boeger, 2002 (Monogenea: Dactylogyridae) from Lutjanus russellii (Bleeker) and L. argentimaculatus (Forsskal) (Teleostei: Lutjanidae) in the South China Sea

“…Euryhaliotrema is now diagnosed mainly by possessing a coiled or meandering male copulatory organ with bulbous or funnel-shaped base, with or without accessory piece serving as guide for the copulatory tube (Kritsky 2012). So far, including the two new taxa described in the present paper, Euryhaliotrema contains 67 species from fish hosts of the Ambassidae, Chaetodontidae, Haemulidae, Lutjanidae, Sciaenidae, and Sparidae (Kritsky 2012, Kritsky andDiggles 2014).…”

“…whose accessory piece does not have articulation to attach to the base of the male copulatory organ ( Table 1). Based on the morphology of the haptoral sclerotised structures, Euryhaliotrema tenuiaccessorium is similar to E. cryptophallus and E. lisae Kritsky et Diggles, 2014. However, the copulatory tube of E. tenuiaccessorium is C-shaped and represented by less than one clockwise ring, rather than J-shaped in E. lisae and a counterclockwise ring in E. cryptophallus.…”