Apocuma chathamensis, Gerken, Sarah, 2013

Gerken, Sarah, 2013, New Zealand Bodotriidae (Crustacea: Cumacea), Zootaxa 3630 (1), pp. 1-38 : 3-6

Apocuma chathamensis n. sp.

Figures 1–2

Type material. Holotype subadult female, NIWA 80743; Paratype subadult female, dissected, NIWA 80744; Paratypes, 2 subadult males, NIWA 80745; 44.0162°S, 178.5210°E – 44.0143°S, 178.5175°E, 769–771 m, 7 April 2007.

Other material examined. 1 subadult female, NIWA 80746, 44.0162°S, 178.5210°E – 44.0143°S, 178.5175°E, 769–771 m, 7 April 2007.

Diagnosis. Female. Carapace expanded ventrolaterally, no dorsal crest. Pereonites and pleonites with dorsal keel extending to pleonite 5. Pereopod 5 carpus long, 0.9 times basis length. Male. Adult unknown.

Description of preparatory female and subadult male. Holotype preparatory female, 5.0 mm, NIWA 80743; paratype preparatory female, 4.3 mm, NIWA 80744; paratype subadult male, 5.2 mm, NIWA 80745. Carapace expanded ventrolaterally, anterolateral corner strongly produced, serrate; pseudorostral lobes 0.3 times carapace length; eye lobe without lenses, broad, 0.04 times carapace length; carapace twice length of pereon. Pereonites 2–5 and pleonites 1–5 with dorsal keel. Pleon longer than carapace and pereon together. Carapace, pereon and pleon covered with fine reticulations. ( Figure 1 A–C).

Description of preparatory female. Antennule peduncle article 1 as long as articles 2 and 3 together, unarmed; article 2 0.6 times article 1 length, with 2 simple and 2 pedunculate setae; article 3 0.6 times article 2 length with simple seta; main flagellum of 3 articles, with 1 aesthetasc and 3 simple setae; accessory flagellum of 1 article, with 2 simple and 1 pedunculate setae ( Figure 1 D).

Mandible navicular, lacinia mobilis with 3 cusps ( Figure 1 E).

Maxillule with 2 endites; outer endite broad, with 9 simple setae, margin lined with fine hairlike setae, with simple seta; inner endite with 2 simple, 1 tricuspid and 1 microserrate setae; palp with 2 microserrate setae ( Figure 1 F).

Maxilla with 3 endites; broad endite with row of simple setae distally, medial distal corner with 2 pappose setae, medial margin with row of 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 ( Figure 1 G).

Maxilliped 1 basis 0.8 times length of all other articles together; ischium absent; merus 0.3 times basis length; carpus 2.6 times merus length, with 6 simple, 5 beak and 1 pappose setae medially, plumose seta laterally; propodus 0.3 times carpus length, with 3 simple and 1 pappose setae; dactylus 0.8 times propodus length, with 3 simple setae terminally ( Figure 1 H).

Maxilliped 2 basis 1.4 times length of all other articles together, with 2 pappose setae; ischium absent; merus 0.4 times basis length, with pappose seta; carpus 0.8 times merus length, with 1 simple and 1 pappose setae; propodus 0.6 times carpus length with 1 pappose and 2 simple setae; dactylus 0.6 times propodus length,with 3 simple setae ( Figure 1 I).

Maxilliped 3 basis 1.3 times length of all other articles together, with 3 pappose setae distally; ischium 0.06 times basis length, unarmed; merus 2.5 times ischium length, with 2 pappose setae; carpus 1.8 times merus length, with 4 pappose setae, medial margin weakly serrate distally; propodus 0.8 times carpus length, with 2 simple and 2 plumose setae; dactylus 0.4 times propodus length, with 3 simple setae terminally; exopod shorter than basis, flagellum with plumo–annulate setae ( Figure 2 A).

Pereopod 1 basis equal to all other articles together, with 2 simple setae, medial margin serrate; ischium 0.04 times basis length, unarmed, produced as 2 teeth medially; merus 4.7 times ischium length, with simple seta, produced as tooth medially; carpus 2.0 times merus length, with 2 simple setae; propodus 0.7 times carpus length, with 3 simple setae; dactylus 0.5 times propodus length, with 3 simple setae terminally; exopod shorter than basis, flagellum with plumo–annulate setae ( Figure 2 B).

Pereopod 2 basis equal to all other articles together, unarmed; ischium 0.05 times basis length, unarmed; merus 3.7 times ischium length, with simple seta; carpus 1.6 times merus length, with 3 simple setae; propodus 0.4 times carpus length, with 2 simple setae, produced as tooth distally; dactylus 2.3 times propodus length, with 3 simple setae terminally; exopod longer than basis, flagellum with plumo–annulate setae ( Figure 2 C).

Pereopod 3 basis 1.5 times length of all other articles together, with simple seta; ischium 0.08 times basis length, unarmed; merus 1.5 times ischium length, with simple seta; carpus 2.2 times merus length, unarmed; propodus 0.6 times carpus length, with annulate seta; dactylus 0.4 times propodus length, with 2 simple setae terminally; exopod absent ( Figure 2 D).

Pereopod 4 basis equal to all other articles together, unarmed; ischium 0.09 times basis length, unarmed; merus 1.8 times ischium length, unarmed; carpus 2.9 times merus length, unarmed; propodus 0.5 times carpus length, with annulate seta; dactylus 0.4 times propodus length, with 2 simple setae terminally ( Figure 2 E).

Pereopod 5 basis 0.7 times length of all other articles together, unarmed; ischium 0.09 times basis length, unarmed; merus 1.7 times ischium length, unarmed; carpus elongate, 6.0 times merus length, unarmed; propodus 0.3 times carpus length, with simple seta; dactylus 0.4 times propodus length, with 2 simple setae terminally ( Figure 2 F).

Uropod peduncles 1.8 times pleonite 6 length, outer margins with hyaline fringe, serrate mid–dorsally. Uropod endopod uniarticulate, 0.8 times peduncle length, with 0–1 lateral simple setae, terminal seta stout, medial margin serrate. Uropod exopod of 2 articles, 0.9 times length of endopod; article 1 0.2 times length of article 2, unarmed; article 2 with stout terminal seta ( Figure 2 G).

Etymology. The species is named chathamensis for the place of collection, the Chatham Rise.

Remarks. The elongated carpus of pereopod 5, 3 times the length of the propodus, is unusual. The only other elongate carpus in the genus is found in the subadult male of A. australiense (Hale 1949) described by Petrescu 2004. However, in Petrescu 2004 the elongate carpus is only figured for the subadult male, with the female having a carpus that is only twice the length of the propodus, while in A. chathamensis the elongate carpus is found in both the subadult males and females.

Apocuma gerkenae Roccatagliata, Alberico & Heard 2012 shares the the lack of a rudimentary exopod on pereopod 3 in the female, but the carpus of pereopod 5 is only equal in length to the propodus and dactylus together, while in A. chathamensis the carpus is twice the length of the propodus and dactylus together.

Figures

FIGURE 1. Apocuma chathamensis n. sp. Holotype preparatory female, NIWA 80743. A, side view. Paratype preparatory female, NIWA 80744. B, dorsal view; D, antennule; E, mandibles; F, maxillule; G, maxilla; H, maxilliped 1; I, maxilliped 2. Paratype subadult male, NIWA 80745. C, side view.

FIGURE 2. Apocuma chathamensis n. sp. Paratype preparatory female, NIWA 80744. A, maxilliped 3; B, pereopod 1; C, pereopod 2; D, pereopod 3; E, pereopod 4; F, pereopod 5; G, pleonite 6 and uropods.