Diasylis dasys, Gerken, Sarah, 2015

Gerken, Sarah, 2015, New Zealand Diastylidae and Gynodiastylidae (Crustacea: Cumacea), Zootaxa 4031 (1), pp. 1-77 : 25

Diasylis dasys n. sp.

( Figs. 12–13 )

Material examined. Holotype: ovigerous female, NIWA 0 93208, TAN0705/49, 44.4862°S, 177.1413°E – 44.4841°S, 177.1416°E, 1235–1239 m, 6 April 2007. Paratype: ovigerous female (dissected), NIWA 0 93212, TAN0705/49, 44.4862°S, 177.1413°E – 44.4841°S, 177.1416°E, 1235–1239 m, 6 April 2007.

Diagnosis. Female and subadult male. Carapace rounded, with few scattered tiny spines on anterior half, with setae on carapace, pereon and pleon; ventral margin smooth; antennal notch absent. Eyelobe without lenses. Pseudorostrum acute, 0.2 times carapace length anterior of eyelobe. Antennule article 2 shorter than article 3. Maxilliped 3 ischium not produced. Pereopod 1 basis ischium merus together shorter than carpus propodus dactylus together, carpus propodus and dactylus subequal. Pereopod 2 carpus 3 times propodus length. Pereopods 3–4 without exopods. Telson triangular, without obvious pre-anal/ post-anal division, with 7–8 lateral setae, more than 0.5 times length of uropod peduncles.

Adult male. Unknown.

Etymology. The species is named from the Greek dasys meaning hairy, in reference to the setae found on the carapace, pereon and pleon.

Description. Ovigerous female holotype 9.4 mm, ovigerous female paratype 8.9 mm. Body ( Figs. 12 A–B). Carapace expanded dorsally posteriorly. Pleon without spines or teeth.

Antennule ( Fig. 12 C) peduncle article 1 longest, with pappose and plumose setae; article 2 shortest, with simple setae; article 3 slender, with few simple setae. Main flagellum of 3 articles, with 2 slender aesthetascs and simple seta; accessory flagellum of 2 articles, more than half length of main flagellum article 1, with simple setae.

Antenna ( Fig. 12 C) of 3 articles, small, slender, with few plumose setae.

Mandibles ( Fig. 12 D) navicular, lacinia mobilis with 3 cusps, medial row of 10–13 microserrate setae.

Maxillule ( Fig. 12 E) with 2 endites, palp with 2 microserrate setae.

Maxilla ( Fig. 12 F) with 3 endites; broad endite medial row of setae pedunculate; narrow endites short, with microserrate setae.

Maxilliped 1 ( Fig. 12 G) propodus lateral margin serrate; carpus and propodus with long plumose setae, carpus without beak setae, with simple and pappose setae.

Maxilliped 2 ( Fig. 12 H) ischium visible.

Maxilliped 3 ( Fig. 12 I) 100:6:7:14:17:11; basis weakly produced distally, with 4 setae, many plumose setae.

Pereopod 1 ( Fig. 13 A) 100:11:14:50:50:50; basis with many plumose setae; dactylus with simple setae, terminal seta not very long.

Pereopod 2 ( Fig. 13 B) 100:2:21:42:13:23; basis produced as strong spine distally, with many plumose setae; carpus with simple seta; dactylus with simple setae; exopod longer than basis.

Pereopod 3 ( Fig. 13 C) 100:13:37:34:13:11; basis with plumose and simple setae; ischium and merus with plumose seta each; carpus with many simple setae; carpus and propodus with annulate setae; dactylus terminal seta simple and short; exopod absent.

Pereopod 4 ( Fig. 13 D) 100:17:33:25:17:11; basis and ischium with plumose setae; merus with simple setae; carpus with many simple and annulate setae; propodus with annulate seta; dactylus terminal seta simple and short; exopod absent.

Pereopod 5 ( Fig. 13 E) 100:14:48:52:17:17; basis with plumose setae; ischium with plumose seta; merus with plumose and simple setae; carpus with many annulate and simple setae; propodus with annulate seta; dactylus terminal seta simple and short.

Telson ( Fig. 13 F) 1.9 times as long as pleonite 6, triangular, with 7–8 lateral setae with single setule, terminal setae short and simple.

Uropods ( Fig. 13 F) peduncles with many short setae with single setule medially; endopod triarticulate, with many short setae with single setule medially, terminal seta short and simple; exopod subequal to endopod, terminal seta simple and long.

Distribution. Chatham Rise, New Zealand, 1235–1239 m.

Remarks. The new species is similar to D. acuminata and D. acanthoelachys in being somewhat globular with small spines on the carapace. However, D. dasys has small spines only on the anterior half of the carapace, and long setae on the carapace, pereon and pleon. In comparison, both D. acuminata and D. acanthoelachys have small spines scattered over the entire carapace, and very few to no setae.

Figures

FIGURE 12. Diastylis dasys n. sp. holotype ovigerous female (NIWA 093208). A, side view. Paratype ovigerous female (NIWA 093212). B, dorsal view; C, antennule and antenna; D, mandibles; E maxillules; F, maxilla; G, maxilliped 1; H, maxilliped 2; I, maxilliped 3.

FIGURE 13. Diastylis dasys n. sp. paratype ovigerous female (NIWA 093212). A, pereopod 1; B, pereopod 2; C, pereopod 3; D, pereopod 4; E, pereopod 5; F, pleonite 6, telson and uropods.