Kontiloleucon australiensis n.gen., n. sp.

(Figs 9–13)

Material examined. Holotype— adult male (dissected), MV J68470, 34°55’47”– 34°56’04”S, 151°08’04”E, 429– 466 m, Oct 22 1988, G.C.B. Poore. Paratypes— ovigerous female, MV J68468, 34°55’47” – 34°56’04”S, 151°08’04”E, 429–466 m, 22 Oct 1988, G.C.B. Poore; ovigerous female (dissected), MV J68469, 34°55’47” – 34°56’04”S, 151°08’04”E, 429–466 m, 22 Oct 1988, G.C.B. Poore. Non-type material— 1 ovigerous female, 3 subadult females, MV J62348, 34°55’47”– 34°56’04”S, 151°08’04”E, 429–466 m, 22 Oct 1988, G.C.B. Poore; 1 ovigerous female, 1 subadult female, 1 subadult male, MV J62347, 34°55’47”– 34°56’04”S, 151°08’04”E, 429– 466 m, 22 Oct 1988, G.C.B. Poore; 1 subadult male, MV J62359, 39°43’30”S, 146°18’48”E, 80 m, 13 Nov 1981, R.W. Wilson.

Diagnosis. Female and subadult male. Carapace with strong serrations dorsally on frontal lobe. Pseudorostrum with long setae terminally. Antennal notch excavate, anteroventral corner acutely produced. Pereopod 1 basis more than half length of all other articles together. Adult male. Carapace similar to female, except antennal notch oblique and anteroventral corner rounded. Antennal flagellum long, of at least 25 articles. Maxilliped 3 to pereopod 3exopods with expanded bases; pereopod 4 exopod basis less expanded.

Etymology. The species is named australiensis after the country of collection, Australia.

Description. Adult male holotype 3.6 mm. Body (Fig. 9 C). Carapace subequal to pereon in length, with stout serrations dorsally on frontal lobe, antennal notch open, carapace weakly expanded ventrally; eyelobe absent; pseudorostrum blunt, with setae terminally. Pleon 0.5 times total body length.

Antennule (Fig. 10 A) article 1 longer than articles 2 and 3 together, with plumose and simple setae; article 2 shortest, with simple and pedunculate setae; article 3 with simple setae. Main flagellum of 4 articles, with simple setae and 2 aesthetascs; accessory flagellum of 2 articles, as long as first two articles of main flagellum, with simple setae terminally.

Antenna (Fig. 10 B) peduncle of 5 articles, articles 1–2 unarmed, article 3 with pappose seta, articles 4–5 with rows of short setae on anterior face; antennal flagellum extending at least to pleonite 5, with at least 25 articles.

Mandibles (Fig. 10 C) truncate, lacinia mobilis with 4 cusps, with 1–2 medial setae.

Maxilliped 3 (Fig. 10 D) 100:6:15:20:12:10; basis with pappose setae, distolateral corner with 3 plumose setae; ischium unarmed; exopod fully developed.

Pereopod 1 (Fig. 10 E) 100:7:17:33:35:26; basis, ischium, merus with plumose setae; carpus, propodus, dactylus with simple setae; exopod basal article 3.2 times width of flagellum.

Pereopod 2 (Fig. 11 A) 100:0:17:19:11:31; basis, merus, carpus with plumose setae; ischium absent; propodus unarmed; dactylus with simple and simple with single setule setae; exopod basal article 4.2 times width of flagellum.

Pereopod 3 (Fig. 11 B) 100:6:11:19:11:2; basis, ischium with plumose setae; merus unarmed; carpus, propodus with simple and annulate setae; dactylus minute, with 2 simple setae; exopod basal article 4.0 times width of flagellum.

Pereopod 4 not examined.

Pereopod 5s and penial lobes (Fig. 11 C) 100:13:21:50:17:4; basis with plumose setae; ischium unarmed; merus with plumose seta; carpus, propodus with simple and annulate setae; dactylus minute, with 3 simple setae; penial lobes subequal to basis in length and width, without setae.

Pleopod 1 (Fig. 11 D) basal article stout, unarmed; rami with plumo-annulate setae

Pleopod 2 (Fig. 11 E) basal article stout, with simple setae; rami with plumo-annulate setae.

Uropods (Fig. 11 F) peduncles 1.3 times pleonite 6 length, with 10 variable length microserrate setae; endopod biarticulate, article 1 1.7–1.9 times length of article 2, with 12 microserrate setae medially, article 2 with 7 microserrate setae medially, 1 microserrate and 0–1 simple setae laterally, terminal seta short, hooked medially, microserrate; exopod subequal to endopod, with 7–9 microserrate setae, 0–1 simple setae, terminal seta short, stout, microserrate.

Ovigerous female paratype 3.3 mm, ovigerous female paratype 3.0 mm. Body (Figs 9 A–B). Carapace 1.1 times length of pereon, with stout serrations dorsally on frontal lobe, antennal notch excavate, anteroventral corner produced acutely; eyelobe absent; pseudorostrum acute, with long setae.

Pleon 0.5 times total body length.

Antennule (Fig. 12 A) article 1 0.8 times articles 2–3 together, with simple setae; article 2 subequal to article 3, with simple setae; article 3 with simple setae. Main flagellum of 3 articles, with simple setae and 2 aesthetascs; accessory flagellum of one article, longer than article 1 of main flagellum, with simple setae terminally.

Antenna (Fig. 12 B) of 2 articles, article 1 larger than article 2, with pappose seta; article 2 slender, with simple setae terminally.

Mandible (Fig. 12 C) truncate, lacinia mobilis with 1 cusp, with simple seta medially.

Maxillule (Fig. 12 D) with 2 endites; palp with one microserrate seta.

Maxilla (Fig. 12 E) with 3 endites; broad endite medial row of 3 simple and 3 pappose setae, distal row of setae simple; narrow endites with long simple setae.

Maxilliped 1 (Fig. 12 F) basis with large plumose seta, lobe with simple setae medially; carpus with simple setae, no beak like setae; plumose setae on propodus less than twice as long as dactylus; dactylus longer than propodus.

Maxilliped 2 (Fig. 12 G) basis with plumose seta medially, with simple setae laterally; without long plumose setae; brood plate with annulate setae.

Maxilliped 3 (Fig. 12 H) 100:7:21:26:14:13; basis with pappose setae medially, distolateral corner with 3 plumose setae; ischium unarmed; exopod fully developed.

Pereopod 1 (Fig. 13 A) 100:5:26:48:45:31; basis with simple and pappose setae; ischium with simple seta; merus, carpus with plumose and simple setae; propodus, dactylus with simple setae.

Pereopod 2 (Fig. 13 B) 100:2:19:28:15:43; basis with simple and plumose setae; ischium unarmed; merus with simple and plumose setae; carpus with simple setae; propodus unarmed; dactylus with simple and plumose setae.

Pereopod 3 (Fig. 13 C) 100:6:8:18:12:2; basis, ischium, merus with plumose setae; carpus with plumose, simple, and annulate setae; propodus with annulate seta; dactylus minute, with simple seta.

Pereopod 4 not examined, broken.

Pereopod 5 (Fig. 13 D) 100:15:15:36:18:3: basis with simple and plumose setae; ischium with plumose and annulate setae; merus unarmed; carpus with simple and annulate setae; propodus with annulate seta; dactylus minute, with simple seta.

Uropods (Fig. 13 E) peduncles 1.3 times length of pleonite 6, with 2 simple and 6 microserrate setae; endopod biarticulate, article 1 1.8 times length of article 2, with 6–8 microserrate setae medially, with 2 pedunculate and 2 simple setae laterally, article 2 with 6 microserrate setae medially, with 1 simple and 1 pedunculate setae laterally, terminal seta simple; exopod subequal to endopod, with 3 plumose and 1 simple setae medially, 3 simple setae laterally, terminal seta simple and long.

Distribution. Continental slope off New South Wales; Bass Strait, Victoria; 80– 466 m.

Remarks. Females of the new species are most likely to be confused with Leucon dolichorhinos, but can be differentiated by the dorsal crest and the length of pseudorostrum. In L. dolichorhinos the dorsal crest is serrate along the entire length, and the length of the pseudorostrum projecting anterior of the eyelobe is about 1/3 of the carapace total length. In Kontiloleucon australiensis only the anterior half of the dorsal crest is serrate, and the pseudorostral lobes project anterior of the eyelobe about ¼ of the total carapace length. Adult males can be readily differentiated from all other leuconid males in Australian waters by the presence of long penial lobes.