Dimorphostylis roccatagliatai, 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 : 37-42

Dimorphostylis roccatagliatai n. sp.

Figs 24–27

Type material. Holotype ovigerous female, NMV J62369 ; paratype ovigerous female, dissected, NMV J46870 ; paratype preparatory female, dissected, NMV J46871 ; paratype adult male, dissected, NMV J46872 ; 11°06'00"S 133°00'00"E, 8 m, G. C. B. Poore, 17 Oct. 1982.

Other material examined. 1 ovigerous female, 4 preparatory females, 1 adult male, 4 subadult males, 1 juvenile, 1 manca, NMV J46873 ; 11°06'00"S 133°00'00"E, 8 m, G. C. B. Poore, 17 Oct. 1982.

Diagnosis. Female and subadult male. Carapace with 2 strong and 1 weak parallel oblique lateral ridges. Telson shorter than pleonite 6, with distinct post-anal portion, without lateral setae, with 2 terminal setae. Adult male. Carapace without ridges. Pleonites 3–4 with stout setae ventrolaterally to entrain antennal flagellum. Antennule with brush of setae on peduncle article 3. Antennae extending past posterior border of telson. Telson with distinct post-anal portion, with 1 pair lateral setae, 2 terminal setae.

Description

Ovigerous female. Holotype ovigerous female, NMV J62369 , 2.6 mm; paratype ovigerous female, NMV J46870 , 3.2 mm; paratype preparatory female, NMV J46871 , 2.4 mm. —Carapace with dorsal ridge, origin near posterior margin, curving dorsal and forward to a point after ⅓ of carapace length, then sweeping ventrally toward antennal notch, not meeting anterior margin of carapace, with strong ridge and inconspicuous weak ridge ventral and parallel to anterior part of dorsal ridge, dorsal fold of frontal lobe with irregular teeth, antennal notch oblique, with teeth; pseudorostral lobes 0.5 × carapace length; eye lobe 0.1–0.2 × carapace length, broader than long, with lenses; carapace 2–3 × length of pereonites together ( Figs 24A–C ).

Paratype ovigerous female, NMV J46870 , 3.2 mm. — Antennule peduncle article 1 0.9 × articles 2 and 3 together, with 1 pappose and 1 simple setae, margin with fine hair-like setae; article 2 0.4 × article 1 length with 2 simple, 2 pappose and 1 pedunculate setae; article 3 1.6 × article 2 length, with 3 simple and 1 pedunculate setae; main flagellum of 3 articles, with 2 aesthetascs; accessory flagellum of 2 articles, 0.5 × main flagellum length, with 2 simple and 2 pedunculate setae ( Fig. 24D ). —Antenna of 3 articles; article 1 with simple seta; article 2 with plumose seta; article 3 with 2 simple and 1 plumose setae ( Fig. 24E ). —Mandible navicular, with 8 or 11 microserrate setae medially, large lacinia mobilis with 3 cusps ( Fig. 24F ). —Maxillule with 2 endites; outer endite with double row of stout simple setae, margin with simple seta and lined with fine hair-like setae; inner endite with 3 simple, 1 microserrate and 1 tricuspid setae; palp with 2 microserrate setae ( Fig. 24G ). —Maxilla with 3 endites; broad endite distal margin with row of simple setae, 3 microserrate and 1 pappose setae, medial margin with row of pedunculate setae; medial narrow endite with 4 microserrate setae terminally; distal narrow endite with 5 microserrate setae terminally; both narrow endites extending to distal corner of broad endite ( Fig. 24H ). —Maxilliped 1 basis expanded as lobe with 6 simple, 5 pappose and 1 microserrate setae, with pappose setae on main article; ischium absent; merus with 2 pappose setae; carpus 3.0 × merus length, with 7 pappose and 1 plumose setae; propodus 0.5 × carpus length, with 3 pappose and 2 plumose setae; dactylus 0.7 × propodus length, with 4 simple setae terminally ( Fig. 24I ). — Maxilliped 2 basis 0.8 × length of all other articles together, with 4 plumose setae distally; ischium 0.04 × basis length, unarmed; merus 7.0 × ischium length, with plumose seta; carpus 1.3 × merus length, with 3 plumose setae medially and plumose seta laterally; propodus 0.8 × carpus length, with 3 plumo-dentate and 2 plumose setae medially, plumose seta laterally; dactylus 0.5 × propodus length, with 4 simple setae terminally ( Fig. 24J ). —Maxilliped 3 basis 1.3 × length of all other articles together, with 8 pappose setae medially, lateral margin lined with fine hair-like setae distally, distal corner weakly produced, with 4 plumose setae; ischium 0.1 × basis length, with pappose seta medially and plumose Paratype preparatory female, NMV J46871 , 2.4 mm. — Pereopod 1 basis 0.5 × length of all other articles together, with 1 simple and many plumose setae; ischium 0.1 × basis length, with 3 plumose setae; merus 2.8 × ischium length, with 2 simple setae; carpus 2.8 × merus length, with 3 simple setae; propodus 1.2 × carpus length, with 13 simple setae; dactylus 0.4 × propodus length, with 3 simple setae and 3 simple setae terminally; exopod 0.7 × basis length, basal article unarmed, flagellum with plumo-annulate setae ( Fig. 25B ).

Paratype ovigerous female, NMV J46870 , 3.2 mm. — Pereopod 2 basis 1.0 × length of all other articles together, with 15 pappose setae; ischium not visible; merus with 2 pappose setae; carpus 1.9 × merus length, with 4 simple setae; propodus 0.4 × carpus length, with 3 simple and 1 pedunculate setae; dactylus 1.7 × propodus length, with 4 simple setae and 3 simple setae terminally; exopod 1.1 × basis length, basal article with 2 simple setae, flagellum with plumo-annulate setae ( Fig. 25C ). —Pereopod 3 basis 1.1 × length of all other articles together, with 1 simple and 6 plumose setae; ischium 0.1 × basis length, with 2 simple setae; merus 3.0 × ischium length, with 9 simple setae; carpus 0.4 × merus length, with 2 simple and 2 annulate setae; propodus 0.6 × carpus length, with 1 annulate and 1 pedunculate setae; dactylus 1.0 × propodus length, with 2 simple setae and simple seta terminally ( Fig. 25D ). — Pereopod 4 basis 0.7 × length of all other articles together, with 10 simple and 2 pedunculate setae; ischium 0.1 × basis length, with 5 simple setae; merus 5.0 × ischium length, with 5 simple setae; carpus 0.6 × merus length, with 4 simple and 2 annulate setae; propodus 0.5 × carpus length, with annulate seta; dactylus 1.0 × propodus length, with simple seta terminally ( Fig. 25E ). —Pereopod 5 basis 0.5 × length of all other articles together, with 6 simple and 2 pedunculate setae; ischium 0.3 × basis length, with 2 simple setae; merus 2.2 × ischium length, with 3 simple setae; carpus 0.8 × merus length, with 5 simple and 1 annulate setae; propodus 0.5 × carpus length, with annulate seta; dactylus 0.8 × propodus length, with 1 simple seta and simple seta terminally ( Fig. 25F ). —Telson 0.9 × length of pleonite 6, with no lateral setae, 2 tiny terminal setae ( Fig. 25G ). —Uropod peduncles 1.9 × pleonite 6 length, 2.3 × telson length, medial margin lined with fine hair-like setae, with scattered small simple setae, with 9 simple setae with single subterminal setule medially. Uropod endopod of 3 articles, medial margin lined with fine hair-like setae, 0.6 × peduncle length; article 1 subequal to articles 2 and 3 together, with 3 simple setae with single subterminal setule medially, simple seta laterally; article 2 0.5 × article 1 length, with simple seta with single subterminal setule medially, with simple seta laterally; article 3 1.0 × article 2 length, with simple seta with single subterminal setule medially, simple seta laterally, simple terminal seta long. Uropod exopod of 2 articles, 0.9 × length of endopod; article 1 0.5 × article 2 length, with simple seta; article 2 with 4 or 6 simple setae, simple terminal seta as long as exopod ( Fig. 25G ).

Adult male. Paratype adult male, NMV J46872 , 3.2 mm. — Carapace unornamented; pseudorostral lobes 0.4 × carapace length; eye lobe 0.1 × carapace length, more than twice as broad as long, with lenses; carapace 2.3 × length of pereonites together ( Figs 26A–B ). —Antennule peduncle article 1 0.9 × length of articles 2 and 3 together, with 1 simple and 1–2 plumose setae, medial margin lined with fine hair-like setae; article 2 0.6 × article 1 length, with 1 or 3 plumose setae; article 3 0.8 × article 2 length, with group of simple setae on lateral face, pedunculate seta on distomedial corner; main flagellum of 5 articles, with 2 aesthetascs and pedunculate seta; accessory flagellum of 3 articles, 0.6 × main flagellum length, with simple seta ( Fig. 26C ). —Antenna extending at least to tips of uropod rami; peduncle of 5 articles; article 5 with ranks of short setae, incompletely circling article; flagellum with long articles, each with several short setae ( Figs 26D–E ). —Maxilliped 3 basis 1.7 × length of all other articles together, with 5 plumose setae medially, lateral corner expanded, with 5 plumose setae; ischium 0.1 × basis length, with 2 plumose setae medially; merus 1.0 × ischium length, with plumose seta medially, plumose seta laterally; carpus 1.3 × merus length, with 2 plumose setae medially, plumose seta laterally; propodus 1.2 × carpus length, with 3 plumose setae medially, simple seta laterally; dactylus 0.7 × propodus length, with 3 simple setae terminally; exopod 0.8 × basis length, basal article with plumose seta, flagellum with plumo-annulate setae ( Figs 26F–G ). —Pereopod 1 basis 0.9 × length of all other articles together, expanded distally to midpoint of merus, with 2 simple and many plumose setae; ischium 0.05 × basis length, unarmed; merus 3.0 × ischium length, unarmed; carpus 2.1 × merus length, with simple seta; propodus 1.2 × carpus length, with 3 simple setae; dactylus 0.4 × propodus length, with 7 simple setae terminally; exopod 0.7 × basis length, basal article unarmed, flagellum with plumo-annulate setae ( Fig. 27A ). —Pereopod 2 basis 1.2 × length of all other articles together, expanded distally to distal border of merus, with 2 simple and 9 plumose setae; ischium 0.1 × basis length, unarmed; merus 1.7 × ischium length, with 4 plumose setae; carpus 1.9 × merus length, with 1 simple and 2 annulate setae; propodus 0.3 × carpus length, with 3 simple setae; dactylus 2.6 × propodus length, with 4 simple setae and 3 simple setae terminally; exopod 0.9 × basis length, basal article with 2 plumose setae, flagellum with plumo-annulate setae ( Fig. 27B ). —Pereopod 3 basis 1.5 × length of all other articles together, expanded distally to midpoint of merus, with 3 simple, 2 plumose and 3 pappose setae; ischium 0.1 × basis length, unarmed; merus 2.2 × ischium length, with 4 simple setae; carpus 0.8 × merus length, with 6 simple and 1 annulate setae; propodus 0.6 × carpus length, with annulate seta; dactylus 0.8 × propodus length, with simple seta and simple seta terminally; exopod 0.9 × basis length, basal article unarmed, flagellum with plumo-annulate setae ( Fig. 27C ). —Pereopod 4 basis 1.0 × length of all other articles together, expanded distally to midpoint of merus, with 3 simple setae; ischium 0.1 × basis length, unarmed; merus 4.5 × ischium length, with 4 simple setae; carpus 0.6 × merus length, with 3 simple and 1 pappose setae; propodus 0.5 × carpus length, with annulate seta; dactylus 0.8 × propodus length, with simple seta and simple seta terminally; exopod 1.1 × basis length, basal article with 2 plumose setae, flagellum with plumo-annulate setae ( Fig. 27D ). —Pereopod 5 basis narrow, with 3 simple setae; ischium with plumose seta; merus 2.2 × ischium length, with 3 simple setae; carpus 0.6 × merus length, with 2 simple and 1 annulate setae; propodus 0.8 × carpus length, with 1 pedunculate and 1 annulate setae; dactylus 0.7 × propodus length, with simple seta and simple seta terminally ( Fig. 27E ). —Pleopod 1 peduncle with 6 simple and 5 plumose setae; endopod uniarticulate, without process, with 4 plumose setae; exopod biarticulate, with 4 plumose setae ( Fig. 27F ). —Pleopod 2 peduncle unarmed; endopod uniarticulate, without process, with 3 plumose setae; exopod biarticulate, with 4 plumose setae ( Fig. 27G ) —Telson 0.8 × length of pleonite 6, with 1 pair simple lateral setae, 2 simple terminal setae ( Fig. 27H ). —Uropod peduncles 2.4 × pleonite 6 length, 2.9 × telson length, with 9–10 simple setae with single subterminal setule and 4 microserrate setae with single subterminal setule medially. Uropod endopod of 3 articles, 0.5 × peduncle length; article 1 1.1 × length of articles 2 and 3 together, with 6 microserrate setae with single subterminal setule medially; article 2 0.5 × article 1 length, with 2 microserrate setae with single subterminal setule medially; article 3 1.0 × article 2 length, with 2 microserrate setae with single subterminal setule medially, terminal seta simple. Uropod exopod 0.8 × length of endopod; article 1 0.3 × article 2 length, with simple seta; article 2 3 simple setae, simple terminal seta as long as exopod ( Fig. 27H ).

Etymology. The species is named roccatagliatai in honor of Daniel Roccagliata, for all his work on the order Cumacea .

Remarks. The most similar species is the new species Dimorphostylis nordaustraliana , which presents an overall similar appearance in the females and males, as well as being a similar size. However, there are differences between D. nordaustraliana and D. roccatagliatai in female carapace morphology and antenna and in both sexes in the proportions of pereopod 1. In females of D. roccatagliatai there are 2 prominent and 1 faint parallel ridges laterally on the carapace, while females of D. nordaustraliana only have one ridge and parallel narrow depression. In both sexes of D. roccatagliatai the propodus of pereopod 1 is no more than 1.2 × the merus length, while in D. nordaustraliana the propodus of pereopod is at least 1.3 × the merus length. In addition, in females of D. nordaustraliana the bases of maxilliped 3 and pereopod 2 are much wider than in D. roccatagliatai . The males of D. nordaustraliana have a slender exopod on pereopod 1 and the pereopods are generally less setose, while in D. roccatagliatai the exopod on pereopod 1 is very broad, and the pereopods are generally more setose.

Figures

Figure 24. Dimorphostylis roccatagliatai n. sp. female.Holotype ovigerous female, 2.6 mm, NMV J62369: (A), side view. Paratype preparatory female, 2.4 mm, NMV J46871: (B), dorsal view. Paratype ovigerous female, 3.2 mm, NMV J46870: (C), side view; (D), antennule; (E), antenna;

Figure 25. Dimorphostylis roccatagliatai n. sp.female.Paratype ovigerous female,3.2 mm, NMV J46870: (A), maxilliped 3; (C), pereopod 2; (D), pereopod 3; (E), pereopod 4; (F), pereopod 5;

Figure 26. Dimorphostylis roccatagliatai n. sp. male. Paratype adult male, 3.2 mm, NMV J46872: (A), side view; (B), dorsal view; (C), antennules; (D), antenna; (E), antenna; (F), maxilliped 3; (G), maxilliped 3. Scale bars A–B = 1.0 mm, C–G = 0.5 mm.

Figure 27. Dimorphostylis roccatagliatai n. sp. male. Paratype adult male, 3.2 mm, NMV J46872: (A), pereopod 1; (B), pereopod 2; (C), pereopod 3; (D), pereopod 4; (E), pereopod 5; (F), pleopods 1; (G), pleopods 2; (H), pleonite 6, telson and uropods. Scale bar = 0.5 mm.