Diagnosis: The oblique mouth, a prognathic lower jaw, a small knob at the synthesis of the dentaries, the absence of distinct bars or stripes, the closely-spaced teeth, and lack of beak-like premaxillaries place this species in Diplotaxodon (Ref. 123828). Diplotaxodon dentatus has a smaller body depth, 26.4-28.4% of standard length, than D. altus (35.1-37.8%), D. greenwoodi (34.2-36.5%), D. macrops (33.9-37.6%), D. apogon (32.4-37.3%), D. aeneus (34.3-37.1%) and D. ecclesi (35.5%); there are more gill rakers on the first ceratobranchial in D. dentatus than in D. longimaxilla, 23-27 vs. 16-21; it has fewer teeth in the outer row of the left lower jaw, 17-25, that are exposed when the mouth is closed and more widely spaced than those of D. limnothrissa, 36-46, which are close together and embedded; it has a shorter snout length, 26.6-29.2% of head length, than D. argenteus, 31.7-34.2%, a longer post-orbital head length, 39.0-41.7% of head length vs. 37.7-38.8%, a narrower cheek depth, 10.6-15.2% of head length vs. 15.3-17.0%, generally more gill-rakers on the first ceratobranchial, 23-27 vs. 20-23, and a greater distance between the anterior origin of the dorsal fin to the posterior insertion of the anal fin, 50.3-53.1% of standard length vs. 49.6-51.2% (Ref. 123828).

Description: Body fusiform, slender, and laterally compressed, deepest at origin of dorsal fin (Ref. 123828). Head elongate, 33.8-36.0% of standard length, length greater than body depth, with lower jaw at oblique angle; eye large, horizontal eye diameter 29.9-33.9% of head length, vertical eye diameter 28.4-33.6% of head length, greater than pre-orbital depth, 15.7-20.0% of head length; snout smaller than orbit diameter, 26.6-29.2% of head length, with premaxillary pedicel to vertical through anterior orbit; cheek shallow, 10.6-15.2% of head length, with 2-3 scale rows; mouth large and superior, lower jaw 38.0-41.2% of head length; teeth on lower and upper jaw caniniform, with space between them about width of tooth, 17-25 in outer row of left lower jaw, and exposed (Ref. 123828). Teeth on pharyngeal jaws unicuspid (Ref. 123828). First ceratobranchial with 23-27 gill-rakers and first epibranchial with 6-8 rakers (Ref. 123828). Dorsal-fin origin posterior to operculum, above insertion of pectoral fin, dorsal-fin spines increasing to maximum length over 8-10 spines; caudal peduncle relatively long, 4.8-5.6 times in standard length; caudal fin emarginate; anal-fin, below vertical through first dorsal-fin ray; anal-fin rayed section rounded, not reaching to caudal-fin base; pectoral-fin origin close behind gill slit; pectoral fin in mature males to anal-fin origin; pelvic fin, short, and not to anal-fin origin (Ref. 123828). Ctenoid scales small, 32-38 in lateral line; upper lateral line with slight upward curve anteriorly, to before posterior insertion dorsal fin; lower lateral line straight through mid-caudal peduncle; 0-1 pored scales posterior to hypural plate; cheek scales 2-3 (Ref. 123828). With 16 abdominal and 18 caudal vertebrae, typical of Diplotaxodon species (Ref. 123828).

Colouration: Preserved males with dark snout; flank dark dorsally, fading lighter ventrally; dorsal fin with black lappets; caudal fin with 5-6 central rays black; anal fin with distal portion of membranes dark grey to black and without egg spots; pelvic fins black and pectoral fins clear; head with black gular region (Ref. 123828). Colouration of preserved females similar to males, but lighter overall (Ref. 123828).