Paradiastylis occidensaustralis, 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 : 59-62

Paradiastylis occidensaustralis n. sp.

Figs 38–39

Type material. Holotype ovigerous female, AM P85786; paratype preparatory female, dissected, AM P85787; 16°29'05"S 123°00'35"E, 12 m, J. K. Lowry, K. B. Attwood, 26 May 2010.

Other material examined. 4 individuals, AM P85788, 25°10'S 113°39'E, 0.5 m, H. E. Stoddart, 6 Jan. 1984 . 3 individuals, AM P85789, 19°59'12"S 117°48'36"E, 41 m, CSIRO, 26 Jun. 1983 . 3 individuals, AM P85790, 19 °58'00"– 19°57'42"S 117°49'36"– 117°49'54"E, 42 m, CSIRO, 26 Jun. 1983 . 1 individual, AM P85791,19 °56'42"S 117°53'48"E, 42–43 m, CSIRO, 26 Aug. 1983. 1 individual, AM P85792, 19 °56'42"– 19°56'24"S 117°53'48"– 117°53'00"E, 41 m, CSIRO, 26 Oct. 1983 .

Diagnosis. Female and subadult male. Carapace with 3 parallel oblique lateral serrate ridges, connected dorsally with short curved ridges, and connected anteriorly with a short vertical ridge ending in a strong spine, with several strong spines on the dorsal margin. Telson more than 1.5 × the length of pleonite 6, without distinct post-anal portion, without lateral setae, with pair of tiny terminal setae. Uropod endopod article 1 longer than articles 2 and 3 together. Adult male. Unknown.

Description

Ovigerous and preparatory females. Holotype ovigerous female, AM P85786, 3.9 mm; paratype preparatory female, AM P85787, 3.8 mm. —Carapace with 3 parallel serrate oblique lateral ridges, connected at the dorsal origin by short ridges, and connected at the anterior terminus with short vertical ridges, with strong tooth at anterior corner of dorsal most parallel ridge, with few strong teeth on dorsal margin, with scattered setae; pseudorostral lobes 0.4 × carapace length; eye lobe 0.1 × carapace length, with dorsal tooth, with lenses; carapace 2.1 × length of pereonites together; antennal notch excavated, ventral corner produced as sharp tooth. Pereonites 3–4 fused dorsally, free ventrally. Pleonite 6 with long setae ( Figs 38A–C ). — Paratype preparatory female, AM P85787, 3.8 mm —Antennule peduncle article 1 0.8 × length of articles 2 and 3 together, with 1 simple and 1 plumose setae; article 2 0.5 × article 1 length, with 13 simple setae; article 3 1.8 × article 2 length, with 5 simple, 2 plumose and 1 pedunculate setae; main flagellum of 3 articles, with 2 long aesthetascs and no setae; accessory flagellum of 2 articles, 0.4 × main flagellum length, with 5 simple and 1 pedunculate setae ( Fig. 38D ). —Mandible navicular, with 12 microserrate setae medially, lacinia mobilis with 2 cusps ( Fig. 38E ). —Maxillule with 2 endites; outer endite with double row of stout setae; inner endite with 2 simple, 1 microserrate and 1 tricuspid setae; palp with 2 microserrate setae ( Fig. 38F ). —Maxilla with 3 endites; broad endite distal with 1 pappose seta, row of simple setae and pappose setae, medial margin with row pedunculate setae; medial narrow endite with 4 microserrate setae terminally; distal narrow endite with 4 microserrate setae terminally; both narrow endites extending only to length of distal corner ( Fig. 38G ). —Maxilliped 1 basis produced as lobe with 5 simple, 2 hook and 6 pappose setae; ischium absent; merus with pappose seta; carpus 0.9 × merus length, with simple and beak setae medially, plumose seta laterally; propodus 0.6 × carpus length, with 5 plumose and 2 microserrate setae; dactylus 0.8 × propodus length, with 3 simple setae ( Fig. 38H ). —Maxilliped 2 basis 0.8 × length of all other articles together, with 2 plumose setae distally; ischium 0.1 × basis length, unarmed; merus 2.0 × ischium length, with plumose seta medially, plumose seta laterally; carpus 1.6 × merus length, with 4 plumose setae medially, 2 plumose setae laterally; propodus 0.9 × carpus length, with 6 simple and 2 plumose setae; dactylus 0.4 × propodus length, with 4 simple setae ( Fig. 38I ). —Maxilliped 3 basis 1.2 × length of all other articles together, with 6 pappose setae medially, expanded distally, with 4 plumose setae; ischium 0.1 × basis length, with pappose seta; merus 0.9 × ischium length, with 2 plumose setae medially, plumose seta laterally; carpus 1.5 × merus length, with plumose seta medially, plumose seta laterally; propodus 1.0 × carpus length, with 4 plumose setae medially, plumose seta laterally; dactylus 0.8 × propodus length, with 5 simple setae terminally ( Fig. 39A ). —Pereopod 1 basis 0.4 × length of all other articles together, with 3 simple and 16 plumose setae, medial margin produced as teeth; ischium 0.1 × basis length, unarmed; merus 1.8 × ischium length, unarmed; carpus 3.8 × merus length, with 7 simple setae; propodus 1.4 × carpus length, with 21 simple setae; dactylus 0.3 × propodus length, with 8 simple setae and 2 simple setae terminally; exopod 0.7 × basis length, basal article unarmed, flagellum with plumo-annulate setae ( Fig. 39B ). —Pereopod 2 basis 0.8 × length of all other articles together, with 10 plumose setae, medial margin produced as teeth distally; ischium 0.03 × basis length, unarmed; merus 9.0 × ischium length, with 3 simple setae; carpus 2.1 × merus length, with 5 simple setae; propodus 0.3 × carpus length, with 3 simple setae; dactylus 2.0 × propodus length, with 6 simple and simple seta terminally; exopod 1.2 × basis length, basal article with 3 plumose setae, flagellum with plumoannulate setae ( Fig. 39C ). —Pereopod 3 basis 1.0 × length of all other articles together, with 13 simple setae; ischium 0.1 × basis length, with 2 simple setae; merus 4.0 × ischium length, with 3 simple setae; carpus 0.5 × merus length, with 4 simple and 1 annulate setae; propodus 0.8 × carpus length, with annulate seta; dactylus 1.0 × propodus length, with 2 setae terminally ( Fig. 39D ). —Pereopod 4 basis 0.7 × length of all other articles together, with 5 simple setae; ischium 0.1 × basis length, with 2 simple setae; merus 4.5 × ischium length, with 2 simple setae; carpus 0.6 × merus length, with 4 simple and 1 annulate setae; propodus 0.5 × carpus length, with annulate seta; dactylus 0.8 × propodus length, with 2 setae terminally ( Fig. 39E ). —Pereopod 5 basis 0.7 × length of all other articles together, with 3 simple setae; ischium 0.1 × basis length, with 2 simple setae; merus 4.3 × ischium length, with 2 simple setae; carpus 0.9 × merus length, with 5 simple and 1 annulate setae; propodus 0.5 × carpus length, with 1 simple and 1 annulate setae; dactylus 0.8 × propodus length, with 2 setae terminally ( Fig. 39F ). —Telson 1.9 × length of pleonite 6, with no stout lateral setae, 2 tiny blunt terminal setae ( Figs 39G–H ). —Uropod peduncles 2.8 × pleonite 6 length, 1.5 × telson length, with 1 simple and 8 simple setae with single subterminal setule medially, 14 simple seta laterally. Uropod endopod of 3 articles, 0.4 × peduncle length; article 1 1.3 × length of articles 2 and 3 together, with 2 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, simple seta laterally; article 3 0.6 × article 2 length, with simple seta with single subterminal setule medially, simple seta laterally, terminal seta simple. Uropod exopod of 2 articles, 1.1 × length of endopod; article 1 0.3 × article 2 length, with simple seta; article 2 with 8 simple setae, terminal seta simple, equal in length with uropod endopod terminal seta ( Fig. 39G ).

Etymology. The species is named occidensaustralis meaning western Australia, the place of collection.

Remarks. The carapace of the new species is similar to many species of Dimorphostylis ; however, the female specimens do not have an exopod on maxilliped 3, requiring that this species be placed in Paradiastylis , and also differentiating them easily from the Dimorphostylis females. The most similar species are D. australis and D. triplicata , both of which have 3 parallel oblique ridges on the carapace and a long, tubular telson. However, in D. australis the female has an exopod on maxilliped 3, and the oblique ridges are not connected by short vertical ridges anteriorly. In P. occidensaustralis the female has no exopod on maxilliped 3, and the oblique ridges are connected anteriorly by short vertical ridges. The carapace of the subadult male of D. triplicata is very similar to the carapace of P. occidensaustralis , but can be differentiated by the proportions of pereopod 1. In D. triplicata the propodus of pereopod 1 is distinctly shorter than the basis, while in P. occidensaustralis the propodus of pereopod 1 is subequal to the basis.

ACKNOWLEDGMENTS. This work was supported by a collections fellowship from the Museum Victoria, a Geddes fellowship from the Australian Museum, and a sabbatical leave from the University of Alaska, Anchorage. All the research and collections staff at the Museum Victoria were welcoming and very helpful, and Jo Taylor and Gary and Lindsey Poore were hospitable as always. The research and collections staff at the Australian Museum were very helpful, particularly Steve Keable, and Penny Berents, Jim Lowry and Lauren Hughes were very hospitable. The comments of Jordi Corbera and another reviewer were instrumental in improving the manuscript.

Figures

Figure 38. Paradiastylis occidensaustralis n. sp. female. Holotype ovigerous female, 3.9 mm, AM P85786: (A), side view. Paratype preparatory female, 3.8 mm, AM P85787: (B), dorsal view; (C), side view; (D), antennule; (E), mandibles; (F), maxillule; (G), maxilla; (H), maxilliped 1; (I), maxilliped 2. Scale bars A–C = 1.0 mm, D–I = 0.5 mm.

Figure 39. Paradiastylis occidensaustralis n. sp. female. Paratype preparatory female, 3.8 mm, AM P85787: (A), maxilliped 3; (B), pereopod 1; (C), pereopod 2; (D), pereopod 3; (E), pereopod 4; (F), pereopod 5; (G), pleonite 6, telson and uropods; (H), telson. Scale bars A–G = 0.5 mm, H = 0.25 mm.