Gnathia biorbis Holdich and Harrison, 1980

(Fig. 9 A–E)

Gnathia biorbis Holdich and Harrison, 1980: 219, fig. 2A–I. — Poore and Lew Ton, 2002: 188.

Material examined. All Heron Island. ♂ (5.1 mm), 23°27’S, 151°55’E, 14 January 1979, outer reef flat in dead coral rock, coll. N.L. Bruce (MTQ W34130) . ♂ (5.2 mm), 3 January 1979, mid reef flat, in dead coral, coll. N.L. Bruce (MTQ W34131) . ♂ (5.2 mm), 23°27’S, 151°55’E, 3 January 1979, inner reef flat in dead coral, coll. N.L. Bruce (MTQ W10685) . ♂ (5.0 mm), 8 January 1979, coral rocks, coll. N.L. Bruce (MTQ W10686) . ♂ (5.2 mm), 23°27’S, 151°55’E, 2 June 1978, reef flat, mid-flat, limestone boulder, dead coral rock, coll. N.L. Bruce (MTQ W10687) .

Remarks. This species has earlier been reported from the Heron Island by Holdich & Harrison (1980). The species is easily recognized by the shape of the cephalosome and having a deep but narrow dorsal sulcus (Fig. 9 A–E). The superior frontolateral processes are more distinct than shown by Holdich & Harrison (1980).

Distribution. Northern Queensland; Townsville, Magnetic Island, Heron Island; intertidal.