Austroleucon dolosolevis, Gerken, Sarah, 2016

Gerken, Sarah, 2016, Leuconidae (Crustacea: Cumacea) from the collections of the Museum Victoria, Australia, Zootaxa 4067 (3), pp. 251-292 : 256-261

Austroleucon dolosolevis n. sp.

( Figs 3–6 )

Material examined. Holotype— adult male, MV J62357 , 39°02’24”S, 148°30’36”E, 120 m, 15 Nov 1981, R.S. Wilson. Paratypes— adult male (dissected), MV J68459 , 39°02’24”S, 148°30’36”E, 120 m, 15 Nov 1981, R.S. Wilson; ovigerous female (dissected), MV J68457 ; adult male, MV J68458 , 39°02’24”S, 148°30’36”E, 120 m, 15 Nov 1981, R.S. Wilson.

Non-type material. 2 ovigerous females, 4 subadult females, MV J62358 , 39°44’48”S, 148°40’36”E, 124 m, 14 Nov 1981, R.S. Wilson.

Diagnosis. Female and subadult male. Carapace with weak serrations dorsally on frontal lobe. Pseudorostrum with short setae terminally. Antennal notch oblique, without teeth or serrations. Pereopod 1 basis less than half length of all other articles together. Adult male. Carapace with dorsal margin smooth. Antennal flagellum of 6 articles. Exopods with expanded bases.

Etymology. From the Greek, dolosus meaning deceitful, in combination with levis , forming dolosolevis , in reference to the similarity between the new species and Austroleucon levis and the likelihood of confusing the two species.

Description. Adult male holotype 3.1 mm, adult male paratype 2.7 mm. Body ( Figs 3 A–B). Carapace 1.7 times pereon length, dorsal margin smooth, antennal notch oblique; eyelobe absent; pseudorostrum broad, extending anteriorly 0.24 times carapace total length, with short setae terminally. Pleon 0.5 times total body length.

Antennule ( Fig. 4 A) article 1 longer than articles 2 and 3 together, with fine hair-like setae on margin; article 2 equal to article 3 length, with simple setae; article 3 with simple seta. Main flagellum of 5 articles, article 1 with pedunculate setae, articles 1–2 each with single stout aesthetasc, articles 4–5 each with single slender aesthetasc; accessory flagellum of 1 article, longer than article 1 of main flagellum, with simple setae.

Antenna ( Fig. 4 B) peduncle of 5 articles; article 1 unarmed; article 2 with pappose seta; article 3 with 2 pappose setae; article 4 with many seta on anterior margin; article 5 with many setae on anterior and posterior margins; flagellum of 6 articles, subequal in length to peduncle.

Maxilliped 3 ( Fig. 4 C) 100:5:13:18:8:8; basis with pappose setae medially, distolateral corner with 4 plumose setae; ischium unarmed; exopod basal article three times width of flagellum.

Pereopod 1 ( Fig. 4 D) 100:8:23:42:38:21; basis, merus and carpus with plumose setae, propodus and dactylus with simple setae; exopod basal article five times width of flagellum.

Pereopod 2 ( Fig. 4 E) 100:3:34:17:17:31; basis with pappose and plumose setae; ischium present, unarmed; dactylus with simple setae; exopod basal article five times width of flagellum.

Pereopod 3 ( Fig. 4 F) 100:6:11:17:17:3; basis with pappose and simple setae; carpus, merus and propodus each with annulate seta; dactylus with simple setae; exopod basal article five times width of flagellum.

Pereopod 4 ( Fig. 4 G) 100:20:12:32:24:4; basis with pappose setae; ischium and merus with stout simple setae; carpus and propodus with annulate setae; dactylus with simple setae; exopod basal article twice width of flagellum.

Pereopod 5 ( Fig. 4 H) 100:17:28:50:17:6; basis with simple and pappose setae; ischium and merus with stout simple setae; carpus and propodus with annulate setae; dactylus with simple setae; small penial lobes present at bases of pereopod 5s, no more than 0.2 times length of basis.

Uropods ( Fig. 4 I) peduncles subequal to pleonite 5, 0.5 times length of exopod, with 3 microserrate setae medially, simple setae laterally; endopod uniarticulate, 0.9 times length of exopod, with many microserrate setae medially, simple seta with single subterminal setule terminally; exopod with simple setae, terminal seta annulate, subterminal seta with single setule.

Ovigerous female paratype 3.4 mm. Body ( Fig. 3 C). Carapace 1.1 times pereon length, with weak teeth dorsally on frontal lobe, antennal notch oblique; eyelobe absent; pseudorostrum extending anteriorly 0.3 times total carapace length, more than in male, with setae terminally. Pleon 0.5 times total body length.

Antennules ( Fig. 5 A) article 1 longer than articles 2–3 together, with simple and plumose setae, margin with fine hair-like setae; article 2 longer than article 3. With stout simple setae distally; article 3 with few simple or sparsely plumose setae. Main flagellum of 3 articles, with aesthetascs, simple and annulate setae; accessory flagellum of 2 articles, longer than article 1 of main flagellum, with simple setae.

Antenna ( Fig. 5 B) of 3 articles, articles 1–2 each with pappose seta, article 3 with short simple setae terminally.

Mandibles ( Fig. 5 C) truncate, lacinia mobilis with 3 cusps, medial row of 2 small simple setae.

Maxillule ( Fig. 5 D) with 2 endites; palp with 2 setae.

Maxilla not examined.

Maxilliped 1 ( Figs 5 E–F) basis with stout pappose seta, medial lobe with plumose and simple setae, pappose setae on merus and propodus short.

Maxilliped 2 ( Fig. 5 G) basis without hyaline fringe; ischium visible.

Maxilliped 3 ( Fig. 5 H) 100:7:17:26:19:10; basis pappose setae medially, distolateral corner with 4 plumose setae; ischium unarmed; exopod basal article 2.5 times width of flagellum.

Pereopod 1 ( Fig. 6 A) 100:8:35:71:60:38; basis with pappose and simple setae; merus with simple seta; carpus with simple and plumose setae; propodus and dactylus with simple setae; exopod basal article twice width of flagellum.

Pereopod 2 ( Fig. 5 I) 100:2:31:33:27:53; basis with simple and plumose setae; ischium with plumose seta; merus with simple and plumose setae; carpus and dactylus with simple setae; exopod basal article twice width of flagellum.

Pereopod 3 ( Fig. 6 B) 100:7:17:29:172; basis with simple and plumose setae; ischium with plumose seta; carpus, merus and propodus with annulate and simple setae; dactylus with simple setae; exopod basal article twice width of flagellum.

Pereopod 4 ( Fig. 6 C) 100:9:26:46:20:3; basis, ischium with simple and plumose setae; merus with simple setae; carpus and propodus with annulate and simple setae; dactylus with simple setae.

Pereopod 5 ( Fig. 6 D) 100:13:30:52:30:4; basis, ischium and merus with plumose and simple setae; carpus and propodus with annulate and simple setae; dactylus with simple setae.

Uropods ( Fig. 6 E) peduncles subequal to pleonite 6 length, with simple and single simple setae with subterminal setule medially; endopod uniarticulate, with 10 setae with subterminal setule medially, stout simple seta with subterminal setule terminally; exopod 1.2 times endopod length, with simple setae medially and laterally, terminal and subterminal setae annulate.

Distribution. Eastern Bass Strait, Tasmania, 120– 124 m.

Remarks. This species can be differentiated from the other two species of Austroleucon by the combination of the oblique, smooth antennal notch and the pereopod 1 basis being shorter than half the length of the rest of the articles together. In A. adiazetos the antennal notch is excavate with a strongly serrate margin, and in A. levis the pereopod 1 basis is longer than half the length of the rest of the articles together.

Figures

FIGURE 3. Austroleucon dolosolevis n. sp. Holotype adult male (MV J 62357): A, side view. Paratype adult male (MV J 68459): B, side view. Paratype ovigerous female (MV J 68457): C, side view.

FIGURE 4. Austroleucon dolosolevis n. sp., paratype adult male (MV J 68459): A, antennule; B, antenna; C, maxilliped 3; D, pereopod 1; E, pereopod 2; F, pereopod 3; G, pereopod 4; H, pereopod 5 s and ventral view of pereonite 5; I, pleonite 6 and uropods.

FIGURE 5. Austroleucon dolosolevis n. sp., paratype ovigerous female (MV J 68457): A, antennules; B, antenna; C, mandible; D, maxillule; E, maxilliped 1; F, maxilliped 1; G, maxilliped 2; H, maxilliped 3; I, pereopod 2.

FIGURE 6. Austroleucon dolosolevis n. sp., paratype ovigerous female (MV J 68457): A, pereopod 1; B, pereopod 3; C, pereopod 4; D, pereopod 5; E, pleonite 6 and uropods.