Aplatysympus neozealanicus, Gerken, 2018

Gerken, Sarah, 2018, The Lampropidae (Crustacea: Cumacea) of the World, Zootaxa 4428 (1), pp. 1-192 : 20-24

Aplatysympus neozealanicus n. sp.

( Figs 1–2 )

Type material. Holotype: subadult female, NIWA 45706 , 42.99°S, 178.99°E, 530 m, Chatham Rise, 24 April 2007 . Paratype: subadult female NIWA 45707 , 42.78°S, 176.28°W, 1026 m, Chatham Rise, 10 April 2007 .

Description. Holotype subadult female NIWA 45706, paratype subadult female NIWA 45707.Subadult female, 4.3 mm. Carapace somewhat flattened, with marginal carina, 3 pairs of large dorsal tubercles, 1 pair large posterior dorsolateral tubercles, lateral carina in center half of carapace, sulcus between lateral ridge and marginal carina; pseudorostral lobes 0.3 carapace length, ventrally directed; eyelobe 0.05, no lenses; carapace 2.2 length of pereonites together ( Fig. 1 A–C).

Antennule peduncle article 1 length equal to articles 2 and 3 combined, unarmed, distal corner produced as 3 teeth; article 2 0.6 article 1 length, with 3 simple setae; article 3 0.8 article 2 length, with 2 simple setae; main flagellum of 3 articles, 1.8 length of article 3, with 3 simple setae and 2 aesthetascs; accessory flagellum of 3 articles, equal to main flagellum length, with 5 simple setae ( Fig. 1D ).

Antenna of 4 articles, articles 1–3 with pappose seta, article 4 with 3 simple setae terminally ( Fig. 1E ).

Mandible navicular, with 12 microserrate setae medially, lacinia mobilis with 3 cusps ( Fig. 1F ).

Maxillule with 2 endites; outer endite with 12 simple and 1 pappose setae; inner endite with 1 simple, 3 pappose and 1 dentate setae; palp with 2 setae ( Fig. 1G ).

Maxilla with 3 endites; broad endite distal margin with pappose, simple and microserrate setae, medial row of 29 setae; medial narrow endite with 4 microserrate setae terminally; distal narrow endite with 5 microserrate setae terminally; both narrow endites extending past distal margin of broad endite ( Fig. 1H ).

Maxilliped 1 basis produced medially as broad lobe, medial margin with row of 8 pappose setae, distal margin with 3 simple, 2 pappose, 1 stout microserrate and 2 hook setae; ischium absent; merus with pappose seta laterally, lateral margin with 1 tooth; carpus 1.4 merus length, with 11 pappose and 7 comb setae medially, plumose seta laterally, lateral margin strongly serrate; propodus 0.7 carpus length, with 2 simple and 4 pappose setae medially, 1 simple and 1 pappose setae laterally; dactylus 0.5 propodus length, with 3 simple setae ( Fig. 1I ).

Maxilliped 2 basis longer than all other articles together, with 1 pappose and 1 plumose setae; ischium unarmed; merus 11.0 ischium length, with pappose seta and tooth medially, plumose seta and tooth laterally, plumose seta mid–article; carpus 1.5 merus length, with 5 plumose setae medially; propodus equal to carpus length, with 1 simple and 4 plumos setae medially, plumose seta laterally; dactylus 0.4 propodus length, with 3 simple setae terminally ( Fig. 1J ).

Maxilliped 3 basis 1.3 all other articles together, with 1 pappose and 2 plumose setae; ischium 0.07 basis length, unarmed; merus 1.5 ischium length, with pappose seta medially, plumose seta laterally; carpus 3.7 merus length, with 6 plumose setae medially; propodus 0.5 carpus length, with 5 plumose setae medially, 2 simple setae laterally; dactylus 0.3 propodus length, with 2 simple setae terminally; exopod 0.8 basis length, basal article unarmed, flagellum with plumo-annulate setae ( Fig. 2A ).

Pereopod 1 broken, not illustrated.

Pereopod 2 basis 0.9 all other articles together, with 2 plumose setae; ischium 0.04 basis length, unarmed; merus 2.7 ischium length, with 2 simple setae; carpus 4.8 merus length, with 3 microserrate setae with single subterminal setule; propodus 0.2 carpus length, with 2 simple setae and microserrate seta with single subterminal setule; dactylus 3.1 propodus length, with simple seta and 4 microserrate setae with single subterminal setule, simple seta terminally; exopod rudimentary, 0.1 basis length, of 2 articles, with 3 simple setae ( Fig. 2B ).

Pereopod 3 basis 1.7 all other articles together, with 3 simple setae; ischium 0.05 basis length, unarmed; merus 2.3 ischium length, with simple seta; carpus 1.8 merus length, with simple seta; propodus 0.8 carpus length, with annulate seta; dactylus 0.3 propodus length, with 2 simple setae terminally; exopod absent ( Fig. 2C ).

Pereopod 4 basis 0.9 all other articles together, with simple seta; ischium 0.08 basis length, unarmed; merus 3.0 ischium length, with simple seta; carpus 2.0 merus length, with simple seta; propodus 0.5 carpus length, with annulate seta; dactylus 0.3 propodus length, with 2 simple setae terminally; exopod absent ( Fig. 2D ).

Pereopod 5 basis 0.5 all other articles together, with 2 simple setae; ischium 0.2 basis length, with simple seta; merus 2.5 ischium length, with simple seta; carpus 1.8 merus length, with 2 simple setae; propodus 0.5 carpus length, with annulate seta; dactylus 0.8 propodus length, with 2 simple setae terminally ( Fig. 2E ).

Telson 2.4 length of pleonite 6, without lateral setae, distal half of margins strongly serrate, 3 short terminal setae ( Fig. 2F ).

Uropod peduncles 3.9 pleonite 6 length, 1.6 telson length, with simple seta with single subterminal setule medially. Uropod endopod of 3 articles, 0.9 peduncle length; article 1 1.3 articles 2 and 3 together, with 3 setae with single subterminal setule medially, medial margin serrate; article 2 0.4 article 1 length, with seta with single subterminal setule medially; article 3 0.9 article 2 length, with seta with single subterminal setule medially, terminal seta with single subterminal setule 0.5 length of article 3. Uropod exopod 0.8 length of endopod; article 1 0.2 article 2 length, unarmed; article 2 4.5 article 1 length, with 2 simple setae medially, simple seta laterally, terminal seta broken ( Fig. 2F ).

Etymology. The species is named neozealanicus in reference to the place of collection, the waters of New Zealand.

Depth. 520–1026 m.

Distribution. Chatham Rise, New Zealand, 43°S, 179–182°E.

Remarks. Aplatysympus neozealanicus is somewhat similar to Watlingia chathamensis in carapace morphology, both possessing three large blunt dorsal tubercles. However, in Aplatysympus neozealanicus the carapace has additional sculpturing with a ridge ventral of the tubercles, and a sulcus between the marginal carina and the ridge ventral of the tubercles. Also, Aplatysympus has three articles in the uropod endopod, while Watlingia has two articles in the uropod endopod.

Figures

FIGURE 1. Aplatysympus neozealanicus n. sp. Holotype female NIWA 45706, A, side view; B, dorsal view. Paratype subadult female NIWA 45707, C, side view; D, antennule; E, antenna; F, mandibles; G, maxillule; H, maxilla; I, maxilliped 1; J, maxilliped 2. Scale bars full body 1.0 mm, all others 0.1 mm.

FIGURE 2. Aplatysympus neozealanicus n. sp. Paratype female NIWA 45707, A, maxilliped 3; B, pereopod 2; C, pereopod 3; D, pereopod 4; E, pereopod 5; F, telson and uropods. Scale bars 0.1 mm.