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.