Monopseudocuma gilsoni ( Gilson, 1906 ) Mccarthy & Gerken & Mcgrath & Mccormack, 2006

Mccarthy, Alison M., Gerken, Sarah, Mcgrath, David & Mccormack, Grace P., 2006, Monopseudocuma a new genus from the North East Atlantic and redescription of Pseudocuma gilsoni B | cescu, 1950 (Cumacea: Pseudocumatidae), Zootaxa 1203 (1), pp. 39-56 : 43-52

publication ID	https://doi.org/ 10.11646/zootaxa.1203.1.2
publication LSID	lsid:zoobank.org:pub:C4922CC6-D8FD-4517-8232-4ACB00ADAD27
persistent identifier	https://treatment.plazi.org/id/03D07B20-B35A-FFDF-FEB0-FED81EFEFAD2
treatment provided by	Felipe
scientific name	Monopseudocuma gilsoni ( Gilson, 1906 )
status	comb. nov.

Treatment

Monopseudocuma gilsoni ( Gilson, 1906) View in CoL , new combination

Pseudocuma longicornis Gilson, 1906: 1–20 , figs 8, 9, 11

Pseudocuma gilsoni Bǎcescu, 1950: 431–434 View in CoL , 466

Neotype: Adult male ( Fig 1 A–B View FIGURE 1 ) ( NHM 2006.318 ) Broadhaven Bay, North West Mayo, Ireland, 34 m, 54º17'5" N, 9º52'27" W. GoogleMaps

Other material examined: Adult male ( Fig 1 C–E View FIGURE 1 ) ( NHM 2006.319 ), north east of Porcupine Bank , on slope, 2765 m, 54º08'00" N, 13º59'01" W. Adult male (dissected, Fig 1 F View FIGURE 1 , Fig 2 A–E View FIGURE 2 , Fig 3 A–E View FIGURE 3 ) ( NHM 2006.320 ), adult female (dissected, Fig 4 A–G View FIGURE 4 , Fig 5 A– F View FIGURE 5 ) ( NHM 2006.323 ), 2 adult females ( NHM 2006.321 – 322 ) north east of Porcupine Bank , on slope, 2200 m, 54º 08'01" N, 13º59'02" W. 6 males, 9 females ( NHM 2006.324 – 333 ), 9 males, 7 females ( NMINH.2006.17–32), Broadhaven Bay, North West Mayo, 34 m, 54º17'5" N, 9º52'27" W, originally labelled Pseudocuma gilsoni (?). Adult male ( NMINH.1998.22.1), Silverstrand, Co. Galway, low water springtide, originally labelled Pseudocuma gilsoni (?) Bǎcescu. Adult male ( NMINH.1998.22.2), Barna, Co. Galway, night plankton haul, originally labelled Pseudocuma gilsoni (?). 45 males, 20 females (ZMUCCRU4967) taken near Anholt, in the Kattegat in 1935 at 20 m, labelled Pseudocuma gilsoni . 7 males, 7 females (ZMUCCRU4947), Frederikshavn, Denmark, 1893, labelled Pseudocuma cercaria . 1 female (ZMUCCRU4963), Samsø, Denmark 1986, labelled Pseudocuma longicornis . Males and females from Helgoland ( MNHU No. 19638, No. 19639, No. 8825) and Kieler Bucht ( MNHU No. 23325, No. 23327), Germany, labelled Pseudocuma longicorne GoogleMaps .

Diagnosis: Carapace with 2 parallel oblique lateral ridges and a third oblique ridge near the posterior border of the carapace; eyelobe with 3 lenses; uropod peduncles more than twice pleonite 6; uropod rami subequal to peduncles, exopod and endopod subequal or endopod slightly longer than exopod.

Description: Neotype adult male ( Fig 1 A–B View FIGURE 1 ). Length 2.1 mm. Carapace length 0.3 X body length, with 2 parallel oblique lateral ridges, and 1 additional ridge near posterior border of carapace; antennal notch absent; pseudorostral lobes 0.5 X carapace length; eyelobe 0.1 X carapace length, with 3 lenses; thoracic somites together 0.7 X carapace length.

Adult male ( Fig 1 C–E View FIGURE 1 ). Length 1.9 mm.

Antenna 1 ( Fig 1D View FIGURE 1 ) extending past pseudorostral lobes; peduncle article 1 longest, margins with fine hairlike setae and 1 plumose seta; article 2 longer than article 3 with fine hairlike setae; article 3 with small simple setae; main flagellum of 5 articles, article 1 broader than other articles with group of 10–15 aesthetasc setae, article 3 with one long multiannulate seta, article 4 with 2 aesthetasc setae, article 5 with multiannulate and simple setae; accessory flagellum tiny, 1 article, 0.5 X length of article 1 of main flagellum, with simple seta distally.

Antenna 2 ( Fig 1 E View FIGURE 1 ) extending to end or just beyond end of pereon; peduncle of 4 articles; articles 1 to 3 unarmed; article 5 with rows of setae along anterior margin; flagellum of 22 articles, single row of setae on each article.

Adult male ( Fig 1 F View FIGURE 1 , Fig 2 A–E View FIGURE 2 , Fig 3 A–E View FIGURE 3 ). Length 2.1 mm.

Maxilla 1 ( Fig 3 C View FIGURE 3 ) outer endite with 2 rows of setae terminally (11–12 setae); inner endite with 5 setae terminally; palp with 2 setae.

Maxilla 2 ( Fig 3 D View FIGURE 3 ) broad endite with 8–9 setae on medial margin, distal margin with simple and pappose setae, 1 plumose seta on lateral margin; inner narrow endite with row of 3 setae; outer narrow endite with row of 3 setae.

Maxilliped 1, see female description

Maxilliped 2 ( Fig 3 B View FIGURE 3 ) basis length subequal to all other articles together, with 2 medial and 1 lateral plumose setae; ischium partly covered by merus, with 1 plumose seta; merus unarmed; carpus longer than propodus, bearing 3 plumose and 3 comb setae medially; propodus subequal to dactylus, bearing 2 simple setae medially, 3 pappose and 1 simple setae distally; dactylus with 1 stout and 4 simple setae terminally.

Maxilliped 3 ( Fig 3 A View FIGURE 3 ) basis length subequal to all other articles together, with 3 plumose setae medially, and 1 long plumose seta on distolateral corner; ischium unarmed; merus 0.5 X carpus with 2 plumose setae; carpus longer than propodus, with 3 comb and 2 simple setae medially, and 2 plumose setae laterally; propodus longer than dactylus with 5 simple setae medially and 1 laterally; dactylus bearing a few simple setae and a stout terminal seta; exopod shorter than basis, flagellum bearing plumoannulate setae.

Pereopod 1 ( Fig 2 A View FIGURE 2 ) basis length shorter than all other articles together, bearing 4 plumose setae medially and 3 laterally; ischium unarmed; merus with 1 plumose seta laterally; carpus longer than propodus, with 3 simple setae medially; propodus longer than dactylus with 3 simple setae; dactylus with 3 simple setae, stout terminal seta longer than dactylus; exopod shorter than basis, flagellum bearing plumoannulate setae.

Pereopod 2 ( Fig 2 B View FIGURE 2 ) basis length shorter than all other articles together, bearing 4 plumose setae medially and 3 laterally; ischium present with simple seta medially; merus with 1 plumose and 2 simple setae medially; carpus 0.7 X basis, with simple setae and 1 microserrate seta with subterminal setule distally; propodus 0.5 X dactylus, with simple setae medially; dactylus with 6 simple setae and short, stout hooklike terminal seta, distal medial margin produced as small thumblike process; exopod longer than basis, flagellum bearing plumoannulate setae.

Pereopod 3 ( Fig 2 C View FIGURE 2 ) basis length longer than all other articles together bearing 2 plumose setae medially and 1 distolaterally; ischium present, with 3 multiannulate setae distally; merus longer than carpus, with 2 simple setae; carpus subequal to dactylus and propodus together, with 2 long multiannulae setae on distolateral corner; propodus equal to dactylus, with 1 long multiannulate seta distally; dactylus with 1 stout seta terminally and 1 slender simple seta medially; exopod flagellum missing.

Pereopod 4 ( Fig 2 D View FIGURE 2 ) basis length subequal to all other articles together, bearing 2 plumose setae medially and 3 laterally; ischium present, with 1 simple and 3 multiannulate setae distally; merus subequal to carpus, with 3 multiannulate setae medially and 1 simple setae distally; carpus with 2 long multiannulate setae distally and 1 broken seta medially; propodus subequal to dactylus with 1 long multiannulate seta; dactylus with complex pedunculate seta and stout terminal seta; exopod longer than basis, flagellum bearing plumoannulate setae.

Pereopod 5 ( Fig 2 E View FIGURE 2 ) basis length shorter than all other articles together, with 3 plumose setae; ischium present, with 2 simple and 2 multiannulate setae distally; merus shorter than carpus, with 3 multiannulate setae medially; carpus with 1 simple and 1 multiannulate seta medially and 1 simple and 2 long multiannulate setae distally; propodus longer than dactylus with 1 long multiannulate and 1 simple setae distally; dactylus with one stout simple seta.

Pleopod ( Fig 1 F View FIGURE 1 ) basal article with 4 plumose setae; rami reduced to single article with 5 shorter plumose setae.

Telson ( Fig 3 E View FIGURE 3 ) 0.6 X pleonite 6, unarmed.

Uropod ( Fig 3 E View FIGURE 3 ) peduncle more than twice pleonite 6, with simple seta medially; endopod 1.1 X peduncle, uniarticule, with 5–6 simple setae medially and lined with fine hairlike setae, 2 terminal setae, stout terminal seta 0.2 X endopod, with single subterminal setule; exopod biarticulate, 0.9 X endopod, article 1 0.2 X article 2, unarmed, article 2 with 2 subterminal simple setae, stout terminal seta 0.2 X exopod with single subterminal setule.

Adult female ( Fig 4 A–B View FIGURE 4 ). Length 2.3 mm. Carapace 0.3 X body length, with two welldefined parallel oblique lateral ridges, and one additional ridge near posterior border of carapace, slight antennal notch present; pseudorostral lobes 0.4 X carapace length; eyelobe 0.1 x carapace length, with 3 lenses; thoracic somites together 0.7 X carapace length.

Antenna 1 ( Fig 4 C View FIGURE 4 ) extending past pseudorostral lobes; peduncle article 1 longest, medial margin with fine hairlike setae and 1 plumose seta; article 2 shorter than article 3 with 1 small simple seta distally; article 3 with simple seta distally; main flagellum of 3 articles, article 1 longer than articles 2 and 3 together, article 2 with simple and aesthetasc setae distally, article 3 with simple setae distally; accessory flagellum tiny, uniarticulate, with 2 simple setae distally.

Antenna 2 ( Fig 4 C View FIGURE 4 ) small, of 1 article, with 1 long plumose seta terminally.

Mandible ( Fig 4 D View FIGURE 4 ) navicular, with row of 5 lifting setae; left mandible with lacinia mobilis; molar process with rows of fine hairlike setae.

Maxilla 1, see male description

Maxilla 2, see male description

Maxilliped 1 ( Fig 4 E View FIGURE 4 ) basis length shorter than all other articles together, produced as broad endite distomedially, endite medial margin with 6 plumose, 1 simple and 2 hook setae, endite distal margin with 5 simple setae, and 1 rounded tubercle with fine hairlike setae at tip; ischium absent; merus with 2 simple setae distally; carpus slightly longer than merus, with long plumose seta on distal lateral corner, with 8 comb and 14 simple setae on medial face; propodus shorter than carpus with 2 plumose setae distally, 1 pappose, 1 comb and 11 simple setae on medial face; dactylus with 1 stout and 3 simple setae distally.

Maxilliped 2 ( Fig 4 F View FIGURE 4 ) basis length subequal to all other articles together, with 3 plumose setae distally; ischium partly covered by merus, with 1 plumose seta; merus unarmed; carpus longer than propodus, bearing 6 comb setae medially and 1 simple seta distally; propodus subequal to dactylus, bearing 2 simple setae medially, 2 plumose and 3 simple setae distally; dactylus with 1 stout and 4 simple setae terminally; rudimentary oostegite with 7 setae.

Maxilliped 3 ( Fig 5 A View FIGURE 5 ) basis length subequal to all other articles together, with 5 plumose setae medially, and 1 long plumose seta distolaterally; ischium unarmed; merus 0.5 X carpus with 2 plumose setae; carpus longer than propodus, with 4 comb setae medially and 2 plumose setae laterally; propodus longer than dactylus with 9 simple setae medially and 1 laterally; dactylus bearing a few simple setae and a stout terminal seta; exopod shorter than basis, flagellum bearing plumoannulate setae.

Pereopod 1 ( Fig 5 B View FIGURE 5 ) basis length subequal to all other articles together, bearing 6 plumose setae medially and 1 distolaterally; ischium with 1 simple seta; merus with 1 plumose seta laterally and 1 simple seta medially; carpus longer than propodus, with 3 simple setae and 1 plumose seta medially; propodus longer than dactylus with 4 simple setae; dactylus with 3 simple and 1 microserrate setae distally, stout terminal seta microserrate and longer than dactylus; exopod shorter than basis, flagellum bearing plumoannulate setae.

Pereopod 2 ( Fig 5 C View FIGURE 5 ) basis length shorter than all other articles together, broad, bearing 5 plumose setae medially; ischium small and unarmed; merus with 1 distal plumose seta; carpus 0.5 X basis, with 1 simple seta and 1 stout seta with subterminal setule distally; propodus 0.5 X carpus, with 3 simple setae distally; dactylus with 1 medial and 3 distal simple setae, terminal seta longer than dactylus; exopod subequal to basis, flagellum bearing plumoannulate setae.

Pereopod 3 ( Fig 5 D View FIGURE 5 ) basis length longer than all other articles together, with 3 plumose setae laterally, and 1 distally; ischium with 2 long multiannulate and 3 simple setae distally; merus subequal to carpus, with 2 multiannulate setae medially; carpus subequal to dactylus and propodus together, with 2 long multiannulae setae distally; propodus equal to dactylus, with 1 long multiannulate seta distally; dactylus with 1 stout and 1 slender simple setae; exopod rudimentary, of 2 articles, with 1 distal and 1 terminal plumose setae.

Pereopod 4 ( Fig 5 E View FIGURE 5 ) basis length subequal to all other articles together, with 1 distal and 1 lateral plumose seta; ischium with 3 distal multiannulate setae, and 1 broken seta; merus subequal to carpus, with 4 multiannulate setae medially; carpus subequal to propodus and dactylus together, with 1 multiannulate seta medially and 2 distolaterally; propodus subequal to dactylus with 1 long multiannulate seta distally; dactylus with complex pedunculate seta and stout terminal seta; exopod rudimentary, of 2 articles, with 1 terminal and 1 distal plumose seta.

Pereopod 5 ( Fig 5 F View FIGURE 5 ) basis length shorter than all other articles together, with 3 plumose setae and 2 small simple subdistal setae; ischium with 1 simple and 2 multiannulate setae distally; merus shorter than carpus, with 2 multiannulate setae distally; carpus with 1 multiannulate seta medially and 2 long multiannulate setae distolaterally; propodus subequal to dactylus with 1 multiannulate and 1 simple setae distally; dactylus with 1 stout simple seta.

Telson ( Fig 4 G View FIGURE 4 ) 0.5 X pleonite 6, unarmed.

Uropod ( Fig 4 G View FIGURE 4 ) peduncle more than twice as long as pleonite 6; endopod subequal to peduncle, uniarticule, with 4 simple setae medially, terminal seta missing (terminal seta 0.2 X endopod in shallow specimens); exopod subequal to endopod, article 1 0.2 X article 2, unarmed, article 2 with 2 subterminal simple setae, stout terminal seta 0.2 X exopod.

Remarks: Monopseudocuma gilsoni is most similar to Pseudocuma in overall structure. P. longicorne , P.simile G.O. Sars, 1900 and P. ciliatum G.O. Sars, 1879 all have two oblique lateral ridges and a further ridge towards the posterior of the carapace. The peduncle of the uropod is long and slender in P. longicorne , P. simile and P. chevreuxi Fage, 1928 . The brush of aesthetasc setae on the male antenna 1 is also present in P.simile .

Males are more easily differentiated than females from Pseudocuma by the presence of one pair of pleopods, rather than two as in Pseudocuma . Different forms of P. longicorne have been described in the past (eg. G.O. Sars 1865; G.O. Sars 1879; G.O. Sars 1900; Gilson 1906; Foxon 1936; Bǎcescu 1950; Fage 1951; Lomakina 1958) and various subspecies have been created ( Bǎcescu 1950). In some descriptions, there is one hooklike seta on the dactylus of pereopod 2, and 12–14 setae on the uropod endopod (G.O. Sars 1900). In others, there are two hooklike setae on the pereopod 2 dactylus, and 10 setae on the uropod endopod ( Bǎcescu 1950; Fage 1951). The female P. longicorne has between 5 (G.O. Sars 1879; Bǎcescu 1950) and 10 (G.O. Sars 1900) setae on the uropod endopod, and the uropod peduncle is shorter than the endopod. P. simile differs in having denticles on the carapace anterolateral angle in both sexes, and in having three hooklike setae on the dactylus of pereopod 2 in the males. In P. ciliatum the endopod of the uropod is lined with long cilia and the peduncle is short relative to the rami.