Paraplatysympus aspericristatus, Gerken, 2018

Gerken, Sarah, 2018, The Lampropidae (Crustacea: Cumacea) of the World, Zootaxa 4428 (1), pp. 1-192 : 105-108

Paraplatysympus aspericristatus n. sp.

( Figs 37–38 )

Type material. Holotype: subadult female, NIWA 45708 , TAN0705 /160, 42.78°S, 176.28°W, 1026 m, Chatham Rise , New Zealand, 16 April 2007.

Diagnosis. Female exopods on pereopods 3 and 4 minute. Telson 2.5 length of pleonite 6, equal in length to uropod peduncles, with 8 pairs lateral setae, with 3 equal terminal setae. Adult male unknown.

Description. Holotype subadult female, NIWA 45708.

Subadult female, 10.1 mm. Carapace dorsoventrally flattened, with 1 pair serrate dorsal ridges, 1 pair short posterior serrate ridges, ventral to dorsal ridge, 1 pair long anterior serrate ridges beginning on pseudorostral lobes and proceeding posteriorly, paired dorsolateral swellings, marginal carina serrate; pseudorostral lobes 0.4 carapace length; eyelobe 0.06 carapace length, no lenses; carapace 1.4 length of pereonites together ( Fig. 37A, B ).

Antennule peduncle article 1 longest, with 2 simple setae; article 2 0.5 article 1 length, margin serrate, with 7 simple and 3 pedunculate setae; article 3 0.7 article 2 length, with 4 simple and 3 pedunculate setae; main flagellum of 5 articles, with 7 simple, 2 pedunculate and 2 aesthetasc setae; accessory flagellum of 3 articles, 1.06 main flagellum length, with 9 simple and 2 pedunculate setae ( Fig. 37C ).

Antenna, mandible not illustrated.

Maxillule with 2 endites; outer endite with 12 stout setae; inner endite with 1 simple, 1 dentate and 3 microserrate setae; palp with 2 setae ( Fig. 37D ).

Maxilla with 3 endites; broad endite distal margin with simple and pappose setae, medial margin with row of 36 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. 37E ).

Maxilliped 1 basis produced distally as broad lobe, distal margin with 6 simple setae, lateral margin with 2 hook setae, 11 pappose setae; ischium absent; merus distal margin serrate, with pappose seta; carpus 2.1 merus length, with 16 pappose and 8 comb setae; propodus 0.5 carpus length, with 5 pappose and 2 simple setae; dactylus 0.8 propodus length, with 3 simple setae ( Fig. 37F ).

Maxilliped 2 basis equal to all other articles together, margin serrate, with 3 plumose and 3 pappose setae; ischium 0.07 basis length, unarmed; merus 3.75 ischium length, margin serrate, with 1 plumose and 1 simple setae; carpus 1.3 merus length, with 1 plumose and 5 pappose setae; propodus 0.7 carpus length, with 5 plumose and 3 simple setae; dactylus 0.7 propodus length, with 5 simple setae ( Fig. 38A ).

Maxilliped 3 basis longer than next 4 articles together, with 12 pappose and 4 plumose setae, not expanded distally; ischium 0.05 basis length, unarmed; merus 2.3 ischium length, with 2 plumose and 2 pappose setae; carpus 3.1 merus length, with 13 plumose setae; propodus 0.6 carpus length, with 7 microserrate and 4 plumose setae; dactylus 0.5 propodus length, with 4 simple setae terminally; exopod longer than basis, basal article with 8 plumose setae, flagellum with plumo-annulate setae ( Fig. 38B ).

Pereopod 1 broken, not illustrated.

Pereopod 2 basis as long as next 4 articles together, margin serrate, with 1 large tooth proximally, with 3 plumose setae; ischium 0.06 basis length, with 2 plumose setae; merus 3.3 ischium length, with 3 plumose setae and 1 microserrate seta with single subterminal setule; carpus 2.6 merus length, with 1 plumose and 6 microserrate setae with single subterminal setule; propodus 0.2 carpus length, with 3 simple setae; dactylus 0.3 propodus length, with 12 simple setae; exopod rudimentary, of 2 articles, basal article with 3 plumose and 2 simple setae, terminal article with 4 simple setae (Fig. 385C).

Pereopod 3 basis 1.8 all other articles together, margin serrate, with 5 simple and 1 plumose setae; ischium 0.04 basis length, with 2 simple setae; merus 5.0 ischium length, with simple seta; carpus 0.7 merus length, with 1 simple and 2 annulate setae; propodus 0.6 carpus length, with 1 simple and 1 annulate setae; dactylus 1.0 propodus length, with 3 simple setae terminally; exopod rudimentary, 0.09 basis length, of 2 articles with 4 simple setae ( Fig. 38D ).

Pereopod 4 basis 2.5 all other articles together, margin with few large teeth, with 4 plumose and 8 simple setae; ischium 0.05 basis length, with 2 simple setae; merus 3.0 ischium length, with simple seta; carpus 0.7 merus length, with 2 annulate setae; propodus 0.7 carpus length, with annulate seta; dactylus 0.3 propodus length, with 3 simple setae terminally; exopod rudimentary, 0.1 basis length, of 2 articles with 4 simple setae ( Fig. 38E ).

Pereopod 5 basis 1.2 all other articles together, margin serrate, with 1 simple, 1 pedunculate and 2 plumose setae; ischium 0.07 basis length, with simple seta; merus 3.0 ischium length, with simple seta; carpus 1.7 merus length, with 1 simple and 2 annulate setae; propodus 0.4 carpus length, with annulate seta; dactylus 0.3 propodus length, with 3 simple setae terminally ( Fig. 38F ).

Telson 2.6 length of pleonite 6, with 8 pairs lateral setae with single subterminal setule, 3 simple terminal setae, as long as lateral setae ( Fig. 38G ).

Uropod peduncles 2.6 length of pleonite 6, 1.0 length of telson, with 7–8 setae with single subterminal setule medially, 3 simple setae laterally. Uropod rami broken, uropod exopod article 1 clearly short ( Fig. 38G ).

Etymology. The species is named aspericristatus from the Latin aspera meaning rough, and cristata for ridges, in reference to the rough appearance of the ridges on the carapace.

Depth. 1023–1026 m.

Distribution. Chatham Rise, New Zealand

Remarks. The two species in the genus have similar carapace morphology, with dentate ridges. However, Paraplatysympus aspericristatus can be differentiated from P. echinolowryi by the minute rudimentary exopods on pereopods 3 and 4 in the female and the telson being equal to the uropod peduncles with eight pairs of lateral setae. In comparison, in P. echinolowryi , the rudimentary exopods on pereopods 3 and 4 in the female are non–natatory but relatively well developed, and the telson is shorter than the uropod peduncles with six pairs of lateral setae. In addition, P. aspericristatus is known from the waters of New Zealand, while P. echinolowryi is known from the southern coast of Australia.

Figures

FIGURE 37. Paraplatysympus aspericristatus n. sp. Holotype subadult female NIWA 45708, A, side view; B, dorsal view; C, antennule; D, maxillule; E, maxilla; F, maxilliped 1. Scale bars full body 1.0 mm, all others 0.1 mm.

FIGURE 38. Paraplatysympus aspericristatus n. sp. Holotype subadult female NIWA 45708 A, maxilliped 2; B, maxilliped 3; C, pereopod 2; D, pereopod 3; E, pereopod 4; F, pereopod 5; G, telson and uropods. Scale bars 0.1 mm.