Cumella alaskensis, Gerken, Sarah, 2009

Gerken, Sarah, 2009, Two new Cumella (Crustacea: Cumacea: Nannastacidae) from the North Pacific, with a key to the North Pacific Cumella, Zootaxa 2149, pp. 50-61 : 57-60

Cumella G.O.Sars 1865

Cumella alaskensis n. sp.

Material examined. Holotype ovigerous female, USNM 1125356, Old Harbor, Kodiak Island, 57°09.401’N, 153°23.321’W, 0 m, 13 June 2003

Paratype ovigerous female, dissected, USNM 1125357 Old Harbor, Kodiak Island, 57°09.401’N, 153°23.321’W, 0 m, 13 June 2003

Other material: 3 ovigerous females, Old Harbor, Kodiak Island, 57°09.401’N, 153°23.321’W, 0 m, 13 June 2003; 1 ovigerous female, Old Harbor, Kodiak Island, 57°09.401’N, 153°23.321’W, 1 m, 13 June 2003; 1 ovigerous female, Knight Island, Prince William Sound, 60°17.950’N, 147°24.510’W, 5 m, 28 June 2004; 1 ovigerous female, Green Island, Prince William Sound, 60°18.000’N, 147°24.450’W, 15 m, 26 June, 2004; 1 subadult male, 2 subadult females, Woody Island, Kodiak Island, 57°46.242’N, 152°21.555’W, 10 m, 6 June 2004.

Diagnosis. Dorsal crest with 5 large spines, uropod peduncle is 0.7 the length of pleonite 6, the uropod endopod is 1.3 the length of the exopod, the endopod bears 2 setae medially, and the medial margins of the peduncle and endopod are smooth with fine hairs.

Description. Holotype ovigerous female, USNM 1125356

Ovigerous female, 2.7 mm. Carapace pigmented anteriorly, dorsal fold with 5 large teeth, antennal notch weak to absent; pseudorostral lobes 0.5 carapace length; eyelobe 0.1 carapace length, lenses present; carapace longer than thoracic segments together ( Figure 5 A, 5B).

Paratype ovigerous female, USNM 1125357

Ovigerous female, 2.7 mm.

Antennule peduncle article 1 longest, with simple seta; article 2 with simple and complex pedunculate setae; article 3 shortest, with simple and complex pedunculate setae; main flagellum of 2 articles, with 2 aesthetasc and 2 simple setae; accessory flagellum minute, of 1 article, with simple and complex pedunculate setae ( Figure 5 C).

Mandible navicular, with 5 microserrate lifting setae ( Figure 5 D).

Maxillule with 2 endites; outer endite with double row of stout setae; inner endite with 4 setae; palp with 2 setae ( Figure 5 E).

Maxilla with 3 endites; broad endite distal margin with simple and pappose setae, medial margin with row of 14 setae; medial narrow endite with 4 microserrate setae terminally; distal narrow endite with 5 microserrate setae terminally; both narrow endites extend to distal margin of broad endite ( Figure 5 F).

Maxilliped 1 basis produced distally as blunt lobe, distal and medial margins with simple setae; ischium absent; merus 0.5 carpus length, with simple setae; carpus medial face lined with pappose and comb setae; propodus 0.5 carpus length, with pappose setae; dactylus slender, equal to propodus length, with simple setae terminally ( Figure 5 G).

Maxilliped 2 basis longer than next 3 articles together, with plumose and simple setae; ischium unarmed; merus 0.8 carpus length, with plumose setae; carpus with plumose setae; propodus with plumose setae; dactylus with simple setae, terminal seta microserrate ( Figure 5 H).

Maxilliped 3 basis subequal to all other articles together, medial margin with plumose setae, distal corner with 3 plumose setae; ischium unarmed; merus subequal to carpus, with plumose setae; carpus with plumose setae; propodus 1.3 carpus length, with plumose setae; dactylus 0.6 propodus length, with simple setae; exopod shorter than basis, flagellum with plumo-annulate setae ( Figure 6 A).

Pereopod 1 basis subequal to next 3 articles together, with simple setae; ischium with simple seta; merus 0.5 carpus length, with simple setae; carpus with simple setae; propodus 0.8 carpus length, with simple setae; dactylus 0.5 propodus length, with simple setae; exopod as long as basis, flagellum with plumo-annulate setae ( Figure 6 B).

Pereopod 2 basis longer than next 4 articles together, with simple setae; ischium unarmed; merus 0.6 carpus length, with simple setae; carpus with simple setae; propodus 0.5 carpus length, with simple setae; dactylus 2.0 propodus length, with stout simple setae with single sub-terminal setule, terminal seta longest; exopod longer than basis, flagellum with plumo-annulate setae ( Figure 6 C).

Pereopod 3 basis longer than all other articles together, with simple and complex pedunculate setae; ischium unarmed; merus, carpus, propodus subequal, merus with simple seta; carpus with simple setae; propodus with simple seta; dactylus 0.3 propodus, with 3 simple setae, stout terminal seta 2.0 dactylus length; exopod absent ( Figure 6 D).

Pereopod 4 basis as long as next 4 articles together, with simple and complex pedunculate setae; ischium unarmed; merus, carpus, propodus subequal, merus unarmed; carpus with simple setae; propodus with simple seta; dactylus 0.3 propodus length, with 3 simple setae, stout terminal seta 3.0 dactylus length; exopod absent ( Figure 6 E).

Pereopod 5 basis subequal to next 3 articles together, with simple setae; ischium with simple seta; merus 0.7 carpus length, with simple seta; carpus with simple setae; propodus subeqal to carpus, with simple seta; dactylus 0.3 propodus length, with simple setae, stout terminal seta 3.0 dactylus length ( Figure 6 F).

Uropod peduncles 0.7 pleonite 6, with 1 simple and 1 simple with single sub-terminal setule setae medially, several setae laterally. Uropod endopod of 1 article, 0.8 peduncle length, with 2 simple setae with single subterminal setule medially, 3 simple and 1 complex pedunculate setae laterally, terminal simple setae with single sub-terminal setule 0.7 endopod length. Uropod exopod of 2 articles, 0.8 length of endopod; article 1 0.4 length of article 2, with single simple seta; article 2 with simple seta, terminal simple seta with sub-terminal setule as long as exopod ( Figure 6 G).

Etymology. The new species is named alaskensis for the place of collection, the shores of southeast Alaska.

Remarks. The new species is most similar to Cumella dentata , C. scabera , C. quadrispinosa , and C. arguta . The new species can be distinguished by the presence of 5 large, unequally distributed spines in the dorsal crest. The dorsal crest in C. dentata is a continuous row of spines, in C. scabera the spines are only present on the anterior half of the crest, in C. arguta there are only 3 spines in the dorsal crest, and in C. quadrispinosa the dorsal crest has 3–4 spines and there is a distinct vertical ridge on the sides of the carapace. Additionally, C. alaskensis can easily be distinguished from C. arguta by the proportions and armature of the uropods. In C. alaskensis the uropod peduncle is 0.7 the length of pleonite 6, the endopod is 1.3 the length of the exopod, the endopod bears 2 setae medially, and the medial margins of the peduncle and endopod are smooth with fine hairs. In comparison, in C. arguta the uropod peduncle is 1.5 the length of pleonite 6, the endopod is equal in length to the exopod, the endopod bears 4 setae medially and the medial margins of the peduncle and endopod are serrate.

Figures

FIGURE 5. Cumella alaskensis n. sp. Holotype ovigerous female USNM 1125356. A, side view; B, dorsal view. Paratype ovigerous female USNM 1125357. C, antennule; D, mandibles; E, maxillule; F, maxilla; G, maxilliped 1; H, maxilliped 2. Scale bars full body 1.0 mm, all others 0.1 mm.

FIGURE 6. Cumella alaskensis n. sp. Paratype ovigerous female USNM 1125357. A, maxilliped 3; B, pereopod 1; C, pereopod 2; D, pereopod 3; E, pereopod 4; F, pereopod 5; G, uropods. Scale bars 0.1 mm.