Apocuma pacificum, Corbera, 2008

Corbera, Jordi, 2008, Deep-sea Bodotriidae (Crustacea: Cumacea) from New Caledonia, Fiji and Indonesia, Zoological Journal of the Linnean Society 152 (2), pp. 227-254 : 246-248

APOCUMA PACIFICUM SP. NOV. ( FIGS 18 , 19 )

Type material: Holotype: preadult female dissected in two slides, New Caledonia, BIOCAL, stn DS59, 23°56.21′S, 166°41.10′E, 2650 m, 2.ix.1985 (MNHN- Cu1093) . Paratypes: same station than holotype, 3 preadult females (MNHN-Cu1094); stn DS14, 20°18.09′S, 167°17.70′E, 3680–3700 m, 13.viii.1985, 2 adult females, both poorly calcified and rather damaged, one without pleon (MNHN-Cu1095); stn CP72, 22°09.02′S, 167°33.18′E, 2100–2110 m, 4.ix.1985, 1 preadult female (MNHN-Cu1096). BIO- GEOCAL, stn CP260 21°00.00′S, 167°58.34′E, 1820–1980 m, 17.iv.1987, 1 preadult female (MNHN- Cu1097); stn KG261 21°02.04′S, 167°02.32′E, 1508 m, 18.iv.1987, 1 preadult female (MNHN-Cu1098).

Diagnosis: Anterolateral angle rounded and with denticles, projected forward up to level of tip of pseudorostrum. Lower lateral carina running backwards from the anterolateral angle, turning up to meet the upper carina and not reaching the lower hind margin of the carapace. Uropod endopod 1-articulate with a single cuspidate seta terminally.

Description: Preadult female 5.5 mm total length. Carapace ( Fig. 18A ) about one-third total length, with a mid-dorsal and two pairs of lateral carinae; upper carina runs backwards sinuously from the pseudorostral lobes; lower carina more sharper than the upper, running backwards from the anterolateral angle, interrupted near the end of carapace and turned up to meet the upper carina surrounding a large lateral sulcus; however, the distal end of this lower carina still persists at the postero-lateral angle and is produced backwards to form a subtriangular lobe; hind end raised into a middorsal hump. Integument rugose, covered by small rounded tubercles. Pseudorostral lobes slightly upturned, meeting in front of the eyelobe. Eyelobe rounded, without lenses. Antennal notch deep, anterolateral angle rounded and with denticles, produced forward up to the tip of pseudorostrum level.

Antennule ( Fig. 18B ), peduncle article 1 as long as the following two articles combined; article 3 shorter than article 2; main flagellum 2-articulate, with two aesthetascs; accessory flagellum rudimentary. Left mandible ( Fig. 18C ) with four teeth on pars incisiva, ten setae between pars incisiva and pars molaris (11 setae on right mandible). Maxillule ( Fig. 18D ) palp with two unequal filaments, inner endite with five setae, three simple, one trifid and one serrulate. Maxilla ( Fig. 18E ), endites with simple and serrulate setae.

Maxilliped 1 ( Fig. 18F ) basis with four setae on inner margin, distally produced reaching carpus; carpus with six hand-like flattened setae on the inner margin; propodus with three cuspidate setae on distal inner corner. Maxilliped 2 ( Fig. 18G ) basis slightly longer than rest of appendage, with two plumose setae distally; merus and carpus of the same length, both with a plumose seta on distal outer corner; propodus shorter than carpus, with three simple setae on inner margin. Maxilliped 3 ( Fig. 19A ), basis longer than rest of appendage, not expanded distally, with three long plumose setae on distal outer corner; merus with a long plumose seta; carpus longer than propodus, the first with three plumose and a simple setae on inner margin. Pereopod 1 ( Fig. 19B ) with well-developed exopod, basis shorter than rest of appendage, with three plumose setae distally; ischium and merus short; carpus longer than propodus; dactylus shorter than propodus. Pereopod 2 ( Fig. 19C ) with well-developed exopod, basis as long as rest of appendage, with a plumose seta on distal lower corner; ischium short with distal plumose seta; merus and carpus of similar length; propodus half length of carpus; dactylus more than twice as long as propodus, with three cuspidate setae terminally. Pereopod 3 ( Fig. 19D ) with rudimentary exopod; basis longer than rest of appendage; merus longer than ischium and shorter than carpus; propodus with a long simple seta on distal corner. Pereopod 4 ( Fig. 19E ), basis as long as rest of appendage; merus twice as long as ischium and shorter than carpus; propodus with a long simple seta on distal corner. Pereopod 5 ( Fig. 19F ), basis rather shorter than rest of appendage; carpus more than twice as long as carpus; propodus with a long simple seta on distal corner.

Uropods ( Fig. 19G ) longer than combined length of pleonites 5 and 6, peduncle 1.5 times as long as rami; endopod 1-articulated, with single cuspidate seta terminally. Exopod 2-articulate, as long as endopod, with single cuspidate seta terminally.

Etymology: Referring to the Pacific Ocean where the specimens were collected.

Remarks: The genus Apocuma was only known from a single species, Apocuma brasiliensis Jones, 1973 , collected from the Atlantic Ocean. Petrescu (2004) described a novel species, A. poorei , from Australian water and he transferred Cumellopsis australiense Hale, 1949 to this genus. Apocuma poorei is the only one of the three species with a large lateral sulcus. However, A. pacificum differs from it because the pereon and the pleon lack a double dorsal keel, the uropod peduncle does not have a strongly serrate margin, the terminal seta of the rami are not fused and the anterolateral angle is not acute but rounded.

Figures

Figure 18. Apocuma pacificum sp. nov. preadult female holotype: A, whole animal in lateral view; B, antenna 1; C, left mandible; D, maxilla 1; E, maxilla 2; F, maxilliped 1; G, maxilliped 2.

Figure 19. Apocuma pacificum sp. nov. preadult female holotype: A, maxilliped 3; B, pereopod 1; C, pereopod 2; D, pereopod 3; E, pereopod 4; F, pereopod 5; G, uropod.