Diastylis enodis, Gerken, Sarah, 2015

Gerken, Sarah, 2015, New Zealand Diastylidae and Gynodiastylidae (Crustacea: Cumacea), Zootaxa 4031 (1), pp. 1-77 : 28

Diastylis enodis n. sp.

( Figs. 14–15 )

Material examined. Holotype: preparatory female, NIWA 0 93200, TAN0705/24, 44.1208°S, 174.8432°E – 44.1242°S, 174.8448°E, 512–513 m, 4 April 2007. Paratype: preparatory female (dissected), NIWA 0 93180, TAN0705/36, 43.8298°S, 176.7102°E – 43.8298°S, 176.7102°E, 479 m, 5 April 2007.

Diagnosis. Female and subadult male. Carapace elongate, smooth, with few short setae anteriorly; ventral margin smooth; antennal notch oblique. Eyelobe without lenses. Pseudorostrum acute, 0.16 times carapace length anterior of eyelobe. Antennule article 2 subequal to article 3. Maxilliped 3 ischium not produced. Pereopod 1 basis ischium merus together longer than carpus propodus dactylus together, carpus and propodus subequal, propodus shorter than dactylus. Pereopod 2 carpus 5 times propodus length. Pereopods 3–4 without exopods. Telson with 10–11 lateral setae, more than 0.5 times length of uropod peduncles.

Adult male. Unknown.

Etymology. The species is named from the Latin enodis , meaning smooth, without knots, in reference to the smooth carapace without any ornamentation except tiny reticulations.

Description. Preparatory female holotype 7.4 mm, preparatory female paratype 8.2 mm. Body ( Figs. 14 A–B). Carapace eyelobe present, as wide as long, but without lenses or obvious visual elements. Pleon unornamented.

Antennule ( Fig. 14 C) peduncle article 1 as long as articles 2 and 3 together, with simple and plumose setae; article 2 with few small setae; article 3 with few simple setae. Main flagellum of 3 articles, with 2 aesthetascs and simple seta; accessory flagellum of 2 articles, more than half length of main flagellum article 1, with simple setae.

Antenna ( Fig. 14 C) of 3 articles, with plumose setae.

Mandibles ( Fig. 14 D) navicular, with row of 15 microserrate setae medially.

Maxillule ( Fig. 14 E) with 2 endites, palp with 2 microserrate setae.

Maxilla ( Fig. 14 F) with 3 endites; broad endite medial row of setae pedunculate; narrow endites with microserrate setae.

Maxilliped 1 ( Fig. 14 G) carpus without beak setae, with simple setae; lateral margin of propodus strongly serrate.

Maxilliped 2 ( Fig. 14 H) basis with many short simple setae on medial margin; ischium not visible.

Maxilliped 3 ( Fig. 14 I) 100:8:9:13:15:8; basis produced distolaterally with 5 plumose setae, with pappose setae.

Pereopod 1 ( Fig. 15 A) 100:7:15:37:35:23; basis with many plumose setae; dactylus with simple setae terminally.

Pereopod 2 ( Fig. 15 B) 100:8:21:55:11:24; basis with alternating plumose and short simple setae, 2 simple setae distally; merus to dactylus with short and long simple setae; dactylus with long simple setae terminally; exopod longer than basis, with many short setae on basal article.

Pereopod 3 ( Fig. 15 C) 100:8:24:16:11:8; basis, ischium and merus with plumose setae; carpus and propodus with simple and annulate setae; dactylus terminal seta simple; exopod absent.

Pereopod 4 ( Fig. 15 D) 100:13:32:26:10:10; basis with plumose setae; ischium and merus with simple setae; carpus and propodus with simple and annulate setae; dactylus terminal seta simple; exopod absent.

Pereopod 5 ( Fig. 15 E) 100:24:43:43:19:19; basis with plumose setae; merus with simple setae; carpus and propodus with simple and annulate setae; dactylus terminal seta simple.

Telson ( Fig. 15 F) 1.9 times as long as pleonite 6, with 10–11 short setae with single setule laterally, terminal setae simple.

Uropods ( Fig. 15 F) peduncles with many short setae with single setule medially; endopod triarticulate, with many short setae with single setule medially, terminal seta short, simple with single setule; exopod longer than endopod, with many short simple setae, terminal seta long.

Distribution. Chatham Rise, New Zealand, 479– 513 m.

Remarks. Diastylis enodis is most similar to D. dasys ; however, the carapace is more elongate, and there are no spines and no long setae on the carapace, the carapace is very smooth.

Figures

FIGURE 14. Diastylis enodis n. sp. holotype subadult female (NIWA 093200). A, dorsal view. Paratype preparatory female (NIWA 093180). B, side view; C, antennule and antenna; D, mandible; E, maxillule; F, maxilla; G, maxilliped 1; H, maxilliped 2; I, maxilliped 3.

FIGURE 15. Diastylis enodis n. sp. paratype preparatory female (NIWA 093180). A, pereopod 1; B, pereopod 2; C, pereopod 3; D, pereopod 4; E, pereopod 5; F, pleonite 6, telson and uropods.