Diastylis kapalae, Gerken, 2014

Gerken, Sarah, 2014, Eleven New Species and a New Genus of Diastylidae (Crustacea: Cumacea) from Australia and One New Species from Canada, Records of the Australian Museum 66 (1), pp. 1-62 : 16-19

Diastylis kapalae n. sp.

Figs 10–11

Type material. Holotype subadult female, AM P85772; paratype subadult male, dissected, AM P85773; 33°40'– 33°43'S 152°04'– 152°06'E, 1108–1115 m, FRV “Kapala”, 19 Dec. 1985 . Paratype subadult male, AM P85774, 33 °37'– 33°39'S 152°02'– 152°04'E, 896–923 m, FRV “Kapala”, 10 Dec. 1980 .

Other material examined. None.

Diagnosis. Female and subadult male. Carapace covered with small spines, two parallel lateral ridges sweeping anteriorly, lined with spines. Pereonites and pleonites with small spines. Telson pre-anal portion lateral margin strongly toothed, lateral setae closely spaced posteriorly, same length as terminal setae. Adult male. Unknown.

Description

Subadult female. Holotype subadult female, AM P85772, 11.5 mm. —Carapace covered with small spines, with two parallel ridges sweeping from mid dorsal anteriorly, lined with spines, branchial regions slightly inflated, with depression dorsally between inflations; pseudorostral lobes 0.5 × carapace length; eye lobe 0.02 × carapace length, without lenses; carapace 1.9 × length of pereonites together. Pereonites and pleonites with spines ( Fig. 10A ).

Subadult male. Paratype subadult male, dissected, AM P85773, 10.5 mm; paratype subadult male, AM P85774, 10.6 mm. —Carapace ornamentation as in holotype female; pseudorostral lobes 0.5 × carapace length; eye lobe 0.04 carapace length, without lenses; carapace 1.8 × length of pereonites together. Pereonites and pleonites covered with spines ( Figs 10B–C ). —Antennule peduncle article 1 longest, with 1 simple and 1 pappose setae, margin with fine hair-like setae, corner produced as tooth; article 2 0.4 × article 1 length, with 4 plumose setae, produced as small tooth distally; article 3 1.9 × article 2 length, with 1 simple and 1 plumose setae; main flagellum of 5 articles, terminal article 0.7 × length of subterminal article, subterminal article with 2 aesthetascs, terminal article with 2 simple setae; accessory flagellum of 4 articles, 0.5 × main flagellum length, with 4 simple setae ( Fig. 10D ). — Mandible navicular, with 12–13 microserrate setae medially, lacinia mobilis with 3 cusps ( Fig. 10E ). —Maxillule with 2 endites; outer endite with double row of stout setae; inner endite with 2 simple, 2 microserrate and 1 tricuspid setae; palp with 2 stout setae ( Fig. 10F ). —Maxilla with 3 endites; broad endite distal margin with row of simple setae, pappose seta, medial margin with row of pedunculate setae and 2 pappose setae; medial narrow endite with 3 simple setae terminally; distal narrow endite with 4 simple setae terminally; both narrow endites extending past distal margin of broad endite ( Fig. 10G ). —Maxilliped 1 basis produced as lobe with 7 simple, 2 hook, 1 plumose and 1 very stout microserrate setae; ischium absent; merus unarmed; carpus 1.7 × merus length, with 4 beak and field of simple setae medially, with 2 plumose setae laterally; propodus 0.6 × carpus length, with 2 plumose and 2 dentate setae; dactylus 0.8 × propodus length, with 3 simple setae terminally ( Fig. 10H ). —Maxilliped 2 basis 1.3 × length of all other articles together, with 1 simple and 4 plumose setae distally; ischium 0.04 × basis length, unarmed; merus 4.0 × ischium length, with 2 plumose setae; carpus 2.0 × merus length, with 4 plumose and 3 pappose setae medially, 2 plumose setae laterally; propodus 0.7 × carpus length, with 6 plumose setae medially, plumose seta laterally; dactylus 0.5 × propodus length, with 7 simple setae terminally ( Fig. 10I ). —Maxilliped 3 basis 2.2 × length of all other articles together, with 13 pappose setae medially, 4 plumose setae at distal corner, medial margin produced as strong teeth, increasing in size distally; ischium 0.06 × basis length, with pappose seta; merus 1.2 × ischium length, with pappose seta medially, plumose seta laterally, medial margin and lateral margin each produced as single large tooth; carpus 1.0 × merus length, with 2 pappose setae medially, 2 plumose setae laterally, medial margin produced as 2 large teeth; propodus 1.8 × carpus length, with 4 plumose setae medially, plumose seta laterally; dactylus 0.7 × propodus length, with 5 simple setae terminally; exopod 0.7 × basis length, basal article unarmed, flagellum with plumoannulate setae ( Fig. 11A ). —Pereopod 1 basis 0.5 × length of all other articles together, with 28 plumose setae, medial margin produced as strong teeth, largest at distal corner; ischium 0.1 × basis length, unarmed; merus 1.9 × ischium length, with 3 plumose setae; carpus 2.7 × merus length, with 3 plumose setae; propodus 1.2 × carpus length, with 3 simple setae; dactylus 1.2 × propodus length, with 13 simple setae and simple seta terminally; exopod 0.7 × basis length, basal article with 8 plumose setae, flagellum with plumo-annulate setae ( Fig. 11B ). —Pereopod 2 basis 0.8 × length of all other articles together, with 1 simple and 12 plumose setae, margins produced as few teeth; ischium 0.07 × basis length, with plumose seta, margin produced as large tooth; merus 3.3 × ischium length, with 6 plumose setae; carpus 2.5 × merus length, with 7 simple setae; propodus 0.3 × carpus length, with 3 simple setae; dactylus 1.8 × propodus length, with 3 simple setae and 5 simple setae terminally; exopod 1.0 × basis length, basal article with 6 plumose setae, flagellum with plumo-annulate setae ( Fig. 11C ). —Pereopod 3 basis 1.5 × length of all other articles together, with 9 plumose setae, produced as scattered teeth; ischium 0.08 × basis length, with annulate seta; merus 2.3 × ischium length, with 2 annulate setae, produced as tooth; carpus 1.1 × merus length, with 1 simple, 3 plumose and 6 annulate setae; propodus 0.5 × carpus length, with 1 annulate and 1 pedunculate setae; dactylus 1.6 × propodus length, with 2 simple setae terminally; exopod 0.9 × basis length, basal article with 2 plumose setae, flagellum with short simple setae ( Fig. 11D ). —Pereopod 4 basis 0.9 × length of all other articles together, with 3 simple and 7 plumose setae, margin produced as few teeth; ischium 0.1 × basis length, with simple seta; merus 2.5 × ischium length, with 2 simple setae; carpus 1.3 × merus length, with 2 simple, 2 plumose and 5 annulate setae; propodus 0.5 × carpus length, with annulate and pedunculate setae; dactylus 1.5 × propodus length, with simple seta and simple seta terminally; exopod 1.2 × basis length, basal article unarmed, flagellum with short simple setae ( Fig. 11E ). —Pereopod 5 basis with 1 simple and 3 plumose setae; ischium with 2 simple setae; merus 2.5 × ischium length, with 3 simple setae; carpus 1.4 × merus length, with 2 simple, 3 plumose and 2 annulate setae; propodus 0.4 × carpus length, with annulate seta; dactylus 1.2 × propodus length, with 2 simple setae terminally ( Fig. 11F ). —Telson 2.3 × length of pleonite 6, with 4 pairs of lateral simple setae with single subterminal setule, two terminal setae with single subterminal setule, margin of pre-anal portion strongly toothed ( Fig. 11G ). —Uropod peduncles 2.5–2.7 × pleonite 6 length, 1.1–1.2 × telson length, with 14 or 16 simple setae with single subterminal setule medially. Uropod endopod of 3 articles, 0.6–0.7 × peduncle length; article 1 longest, with 5 simple setae with single subterminal setule medially; article 2 0.4–0.6 × article 1 length, with 2–3 simple setae with single subterminal setule medially; article 3 subequal to article 2, with 2 simple setae with single subterminal setule medially, 0–1 pedunculate and 0–1 simple setae with single subterminal setule laterally, terminal seta simple with single subterminal setule. Uropod exopod 0.9 × length of endopod; article 1 0.3 × article 2 length, with 0–1 simple seta; article 2 with 5 or 8 simple setae with single subterminal setule laterally, 0–1 simple seta with single subterminal setule medially, terminal seta simple with single subterminal setule ( Fig. 11G ).

Etymology. The new species is named kapalae for the research vessel that collected the specimens, the FRV Kapala.

Remarks. The telson of this species is unique in the Australian diastylid fauna, in being relatively large, with strong teeth on the margins of the pre-anal portion, with 4 pairs of lateral setae closely clustered together and the terminal setae similar in size to the lateral setae on the post-anal portion of the telson. The carapace ornamentation is also unique within the Australian diastylid fauna. This is a large species, as the only specimens observed were more than 10 mm and subadult.

Figures

Figure 10. Diastylis kapalae n. sp. female, male. Holotype female, 11.5 mm, AM P85772: (A), dorsal view. Paratype subadult female, 10.5 mm, AM P85773: (B), dorsal view; (D), antennule; (E), mandibles; (F), maxillules; (G), maxilla; (H), maxilliped 1; (I), maxilliped 2. Paratype subadult male, 10.6 mm, AM P85774: (C), side view. Scale bars A–C = 5.0 mm, D–I = 0.5 mm.

Figure 11. Diastylis kapalae n. sp. female. Paratype subadult female, 10.5 mm, AM P85773: (A), maxilliped 3; (B), pereopod 1; (C), pereopod 2; (D), pereopod 3; (E), pereopod 4; (F), pereopod 5; (G), pleonite 6, telson and uropods. Scale bar = 1.0 mm.