Gnathia cornuta Holdich and Harrison, 1980

(Fig. 18 A–E)

Gnathia cornuta Holdich & Harrison, 1980: 225, fig. 4A–I. — Poore & Lew Ton, 2002: 188.

Material examined. ♂ (3.1 mm), Heron Island, ‘ Canyons’, reef slope, 23°28.389’S, 151°57.835’E, 8 December 1979, in dead coral, 7 m, coll. N.L. Bruce (MTQ W10701) . 2 ♂ (3.1, 3.4 mm), Wistari Reef, off northern side of reef, 7 November 1978, in sediments, 22 m, coll. D. Fisk (MTQ W10700) .

Remarks. This species is easily recognized on basis of the large paraocular tubercle, with its two V-shaped ridges and the internal lobe of the mandible (Fig. 18E) having a coarse crenulation. The mandibular lobe is short (Fig. 18A, B) in some specimens, while in larger specimens it reaches almost to the margin of the blade. Additional characteristic of the species is a fine crenulation laterally on the basal neck of the mandible (Fig. 18B, C).

This is the first report of the species from Heron Island. The species was previously only recorded from the Pallarenda, Townsville, Northern Queensland. Distribution. Northern Queensland (Townsville, Heron Island); from the intertidal to depths of 22 m.