Austroleucon adiazetos Gerken, 2016, n. sp.
Creators: name: Gerken, Sarah
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Cumacea
Leuconidae
Austroleucon
Austroleucon adiazetos

description: Austroleucon adiazetos n. sp.
(Figs 1–2)
Material examined. Holotype— ovigerous female, MV J68454, 39°02’24”S, 148°30’36”E, 120 m, 15 Nov 1981, R.S. Wilson. Paratypes— ovigerous female (dissected), MV J68455, 39°02’24”S, 148°30’36”E, 120 m, 15 Nov 1981, R.S. Wilson; 1 ovigerous female, 1 subadult female, 1 subadult male, MV J68456, 39°02’24”S, 148°30’36”E, 120 m, 15 Nov 1981, R.S. Wilson.
Diagnosis. Female and subadult male. Carapace with strong teeth dorsally on central third. Pseudorostrum 0.3 times carapace length. Antennal notch excavate, serrated. Pereopod 1 basis less than half length of other articles together.
Adult male. Unknown.
Etymology. The species is named from the Greek, adiazetos, meaning unpolished or rough, in reference to the strongly serrate antennal notch and strong teeth in the dorsal crest.
Description. Ovigerous female holotype 4.0 mm, ovigerous female paratype 4.3 mm. Body (Figs 1 A–B). Carapace 1.4 times length of pereon, with strong teeth dorsally from apex of frontal lobe just under half way to posterior border; antennal notch distinctly excavate, small, serrated with teeth extending anteriorly onto ventral border of pseudorostrum; eyelobe absent; pseudorostrum extending anterior of frontal lobe 0.3 times carapace length, with setae terminally. Pleon 0.45 times total body length.
Antennule (Fig. 2 A) article 1 longer than articles 2–3 together, with 2 plumose setae and margin with fine hair like setae; article 2 equal to article 3 length, with simple setae; article 3 with plumose seta. Main flagellum of 1 article, shorter than accessory flagellum, with stout simple setae but no aesthetascs; accessory flagellum of 2 articles, longer than main flagellum, with slender simple setae.
Antenna not examined.
Mandibles (Fig. 2 B) truncate, lacinia mobilis with 2 cusps, medial row of 2 simple setae.
Maxillule (Fig. 2 C) with 2 endites; palp with seta.
Maxilla (Fig. 2 D) with 3 endites; broad endite medial row of setae pappose; narrow endites with simple setae.
Maxilliped 1 (Fig. 2 E) basis medial lobe with few setae; carpus with simple setae medially.
Maxilliped 2 (Fig. 2 F) basis with hyaline fringe on lateral margin; ischium visible.
Maxilliped 3 (Fig. 2 G) 100:6:17:30:19:13; basis medial margin with pappose setae, with 2 very stout plumose setae at distolateral corner; ischium unarmed; exopod fully developed, basal article subequal to flagellum width.
Pereopod 1 (Fig. 2 H) 100:8:38:73:67:42; basis 0.44 times length of all other articles together, with pappose, plumose and simple setae; exopod basal article twice width of flagellum.
Pereopod 2 (Fig. 2 I) 100:5:34:32:21:55; ischium present; exopod basal article twice width of flagellum.
Pereopod 3 (Fig. 2 J) 100:9:19:23:16:2; basis with simple and plumose setae; ischium with plumose and simple setae; merus with plumose setae; carpus with annulate setae; propodus with annulate seta; dactylus with simple setae; exopod basal article three times width of flagellum.
Pereopod 4 (Fig. 2 K) 100:13:23:31:10:10:3; basis with plumose and simple setae; ischium with simple setae; merus with simple setae; carpus with annulate setae; propodus with annulate seta; dactylus with simple seta.
Pereopod 5 (Fig. 2 L) 100:26:22:39:30:4; basis with plumose setae; ischium with annulate and plumose setae; merus with annulate seta; carpus with annulate and simple setae; propodus with annulate seta; dactylus with simple seta.
Uropods (Fig. 2 M) peduncles subequal to pleonite 6 length, unarmed; endopod uniarticulate, 0.8 times exopod length, with 8–9 microserrate setae with subterminal setule medially, microserrate setae with subterminal setule terminally; exopod with weakly microserrate medially, weakly microserrate seta terminally.
Distribution. Eastern Bass Strait, Tasmania, 120 m.
Remarks. This species can be differentiated from the other two species of Austroleucon by the antennal notch being excavate with a strongly serrate margin. In comparison, in both A. dolosolevis and A. levis the antennal notch is oblique and the margin is smooth. However, in specimens that are transparent or weakly calcified, it may be difficult to observe the antennal notch. A subadult male was observed in the pre-adult molt, and the antenna was clearly short, making the generic placement of this species indisputable.
description: Published as part of Gerken, Sarah, 2016, Leuconidae (Crustacea: Cumacea) from the collections of the Museum Victoria, Australia, pp. 251-292 in Zootaxa 4067 (3) on pages 253-256, DOI: 10.11646/zootaxa.4067.3.1, http://zenodo.org/record/263497