Wilhelm's hawkfish

Background

Wilhelm's hawkfish was first formally described in 1972 as Cirrhitus wilelmi, with the type locality given as Easter Island in the southern Pacific Ocean. In 2001, John Ernest Randall placed it in a new monotypic genus, Itycirrhitus, because this species and Notocirrhitus splendens differed in having smaller thoracic scales.

However, molecular phylogenetic analysis suggests that Itycirrhitus is closer to Neocirrhites than to Notocirrhitus. The genus name combines itys, Greek for 'rim', referring to the vivid red scale edges, with Cirrhitus, the type genus of Cirrhitidae. The specific name honors Ottmar Wilhelm (1898–1974), former Director of the Institute of Biology, University of Concepción, who collected the type specimen in 1956.

Description

In description, the species has a snout that is not overly elongated and a deep body. The mouth has an outer row of canine teeth and an inner row of much smaller villiform teeth, with canines notably larger at the front of the upper jaw and side of the lower jaw. There are two rows of cirri and a flap on the posterior edge of the anterior nostril. The caudal fin is truncate or gently rounded.

The upper margin of the preoperculum has fewer than 13 large serrations. The thoracic gill membrane is scaled, but the scales are small compared to those on the body. The dorsal fin has 10 spines (the fourth longest) and 12–14 soft rays (rarely 12 or 14), with weakly incised membranes between spines. The anal fin has 3 spines and 6 soft rays.

The pectoral fin has the lower six rays robust and unbranched. In alcohol, the overall color is bluish green with five vertical brownish bands along the flanks that become indistinct after crossing the lateral line; the snout and area between the eyes are plain brown, and there is a dark spot on the gill cover behind the eye.

Distribution and habitat

Distribution and habitat: Wilhelm's hawkfish has only been recorded from waters off Easter Island and Pitcairn Island, at depths between 1 and 55 m over rocky substrates.