Cryptocopoides obaloba Jóźwiak & Błażewicz-Paszkowycz, 2015

Jakiel, Aleksandra, Stępień, Anna, Jóźwiak, Piotr, Serigstad, Bjørn & Błażewicz-Paszkowycz, Magdalena, 2015, First record of Tanaidacea (Crustacea) from a deep-sea coral reef in the Gulf of Guinea, Zootaxa 3995 (1), pp. 203-228 : 216-220

Cryptocopoides obaloba Jóźwiak & Błażewicz-Paszkowycz sp. nov.

Figs 10–12

Material examined. Holotype —non-ovigerous female (Cat. No. ZMBN 105690), Sta II BR, Gulf of Guinea, 4°45'50.8"N 3°09'14.8"W, depth 376 m, 23 November 2012.

Paratypes —seven non-ovigerous females (one dissected) (Cat. No. ZMBN 105691), Sta III BR, Gulf of Guinea, 4°46'14.2"N 3°08'48.8"W, depth 375 m, 23 November 2012.

Diagnosis. Each of pereonites 1–3 and pleonites with pair of setae; pleonites with low sternal processes. Antenna article-2 with two distal setae. Maxillipedal basis with pair of long setae, each endite with pair of distal setae. Cheliped basis with scale like structures ventrally. Pereopod-6 ischium with two setae. Pereopods 1 and 4 (at least) carpus with spatulate setae distally. Uropods with bisegmented rami.

Etymology. ‘Obaloba’ in Ghanaian slang means fatty or well-built and refers to the most robust body of all tanaidaceans in the examined collection.

Description of female. Body ( Fig. 10 A, C) compact, length 1.5 mm (holotype 1.5 mm; others 1.3–2.1 mm). Cephalothorax about as long as pereonites 1–4 combined length; eyes absent. Pereonites width/length ratio 1.5, 1.8, 1.9, 2.2, 1.9, 1.2 respectively; pereonites 1–3 each with one lateral seta; pereonite-6 shortest; pereonites 2–3 subequal; pereonite-4 longest, one-third as long as cephalothorax. Pleon of five subequal pleonites; each pleonite with lateral setae (pleonites 1–3 with one, pleonites 4–5 with two setae). Pleotelson semicircular, as wide as long, 2.5 times as long as last pleonite, bearing two distal setae. Pereonite-1 and pleonites ( Fig. 10 B) with slight rounded sternal processes.

Antennule ( Fig. 11 A) article-1 rectangular, 1.7 times as long as wide, 0.7 times as long as distal three articles combined, slender, with outer distal two tufts of two and three penicillate setae, outer distal simple seta longer than article-2 and penicillate short seta on inner distal margin; article-2 as long as wide, 0.5 times as long as article-1, with three penicillate outer distal setae, simple seta distally, and three simple setae on inner distal margin; article-3 just longer than wide, 0.6 times as long as article-2, with simple outer distal seta, one penicillate and one simple setae on inner distal margin; article-4 slender, 0.7 times as long as proximal article, with six distal setae.

Antenna ( Fig. 11 B) of six articles, article-1 compact, naked; article-2 twice as long as wide, 1.5 times as long as article-1, with spine and simple seta; article-3, with distal simple seta; article-4 longest, slightly curved, three times as long as article-3 and four times as long as wide, with four penicillate, two long simple and one short setae distally. Article-5 0.5 times as long as article-4 with distal seta; article-6 tiny with five distal setae.

Mouthparts. Labrum ( Fig. 11 C) hood-shaped, distally densely setose. Right mandible ( Fig. 11 D) incisor with blunt tooth, molar stout, with distal array of teeth. Left mandible not observed. Maxillule ( Fig. 11 E) endite with nine slender distal spines and finely setulose outer distal margin; palp with distal seta. Labium ( Fig. 11 F) bilobed Maxilliped ( Fig. 11 G) basis with pair of seta; endite with two simple setae and one short on mid-outer margin and two tubercles distally. Palp article-1 with outer distal seta and microtrichia along outer margin; article-2 with three long distomedial setae; article-3 distally with four plumose and one simple inner setae, and three combs of microtrichia on outer margin distally; article-4 with five plumose distal setae and simple seta on outer margin.

Cheliped ( Fig. 12 A) sclerite narrow, elongated, and extending posteriorly beneath carapace ( Fig 10 C); basis 1.6 times as long as wide, with simple distodorsal seta and with scale-like structures ventrally; merus triangular with simple ventral seta; carpus 1.6 times as long as wide, with two midventral setae and middorsal seta; propodus slender, as long as carpus, 1.4 times as long as wide; fixed finger 0.6 times as long as propodus, with two ventral setae and three setae on inner margin; dactylus as long as fixed finger, naked.

Pereopod-1 ( Fig. 12 B); basis slender, nine times as long as wide, with two dorsoproximal simple setae and row of microtrichia on ventral margin; ischium with ventral seta; merus 0.2 times as long as basis, with two ventrodistal setae; carpus 2.1 times as long as merus, with two dorsodistal and two ventrodistal simple setae, microtrichia present; propodus 1.1 times as long as carpus, with five simple setae distally; dactylus half as long as unguis, with simple seta. Dactylus and unguis combined 0.7 times as long as propodus.

Pereopod-2 ( Fig. 12 C) basis five times as long as wide, with two penicillate dorsoproximal setae and penicillate ventral seta; ischium with ventral seta; merus 0.7 times as long as carpus, with two ventrodistal setae; carpus with three ventrodistal setae and two dorsodistal setae; propodus 1.2 times as long as carpus, with one ventrodistal and one dorsodistal setae, dorsodistal pointed apophysis; dactylus 0.8 times as long as propodus.

Pereopod-3 ( Fig. 12 D) basis 6.3 times as long as wide, with simple dorsoproximal seta and penicillate ventral seta; ischium with ventral seta; merus 0.5 times as long as carpus, with two ventrodistal setae; carpus with two ventrodistal setae, two dorsodistal setae and row of microtrichia dorsally; propodus as long as carpus, with ventrodistal seta and two dorsodistal setae, slightly pointed apophysis and row of microtrichia on dorsal margin; dactylus 0.7 times as long as propodus, with two simple setae.

Pereopod-4 ( Fig. 12 E) basis five times as long as wide, with two penicillate setae at midlength; ischium with two ventrodistal setae; merus 0.8 times as long as carpus, with two ventrodistal strong setae; carpus with spatulate seta and four strong simple setae distally, row of microtrichia on ventral margin; propodus 1.4 times as long as carpus, with two ventrodistal setae, dorsodistal simple seta and middorsal penicillate seta; dactylus 0.8 times as long as propodus.

Pereopod-5 ( Fig. 12 F) as pereopod-4, but basis with three penicillate setae and carpus with penicillate seta at midlength and five simple distal setae.

Pereopod-6 ( Fig. 12 G) as pereopod-5, but basis with only one penicillate seta; propodus with three dorsodistal setae, and two ventrodistal setae.

Pleopods ( Fig. 12 H) all alike, with naked basis; endopod shorter than exopod, with seven setae; exopod with proximal seta separated from twelve distal setae.

Uropod ( Fig. 12 I) biramous; basis robust with seta; endopod longer than exopod with two segments, segment- 1 naked, segment-2 with five long simple setae and penicillate seta distally; exopod segment-1 with long distal seta, segment-2 with one long and one short setae distally.

Distribution. The species is known only from station II and III, from the depth range 375– 376 m.

Remarks. Cryptocopoides obaloba sp. nov. can be distinguished from the other members of the genus mainly by the setation of the pleopods. The new species has seven and twelve setae on the exopod and endopod, respectively. In all other species, the maximum number of setae on the pleopodal exopod is five in C. pacificus ( McLelland 2007) and, on the endopod, seven in C. antarcticus ( Vanhöffen 1914) . Moreover, the new species has one pair of dorsolateral setae on pereonites1–3 and two pairs on pleonite 1–5.

Figures

FIGURE 10. Cryptocopoides obaloba sp. nov., holotype female. A, C, body lateral view; B, pleonites ventral margin, lateral view. Scale bar: 0.5 mm.

FIGURE 11. Cryptocopoides obaloba sp. nov., female. A, antennule; B, antenna; C, labrum; D, right mandible; E, maxillule; F, labium; G, maxilliped. Scale bar: 0.1 mm.

FIGURE 12. Cryptocopoides obaloba sp. nov., female. A, cheliped; B, pereopod- 1; C, pereopod- 2; D, pereopod- 3; E, pereopod- 4; F, pereopod- 5; G, pereopod- 6; H, pleopod; I, uropod. Scale bars: 0.1 mm.