Bathyleptochelia chingilingi Stępień & Jakiel, 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 : 212-216

Bathyleptochelia chingilingi Stępień & Jakiel sp. nov.

Figs 7–9

Material examined. Holotype —non-ovigerous female (Cat. No. ZMBN 105686), Sta I BR, Gulf of Guinea, 4°45'40.7"N 3°09'10.8"W, depth 386 m, 17 November 2012.

Paratypes —three non-ovigerous females (one dissected) (Cat. No. ZMBN 105687), Sta I BR, Gulf of Guinea, 4°45'40.7"N 3°09'10.8"W, depth 386 m, 17 November 2012; seven non-ovigerous females (Cat. No. ZMBN 105688), Sta II BR, Gulf of Guinea, 4°45'50.8"N 3°09'14.8"W, depth 376 m, 23 November 2012; six nonovigerous females (one dissected) (Cat. No. ZMBN 105689), Sta III BR, Gulf of Guinea, 4°46'14.2"N 3°08'48.8"W, depth 375 m, 23 November 2012.

Diagnosis. Cephalothorax shorter than first three pereonites, with two pairs of setae laterally. Antennule with fourth minute cap-like article. Antenna articles 2–3 with strong seta and spine, respectively. Mandible lacinia mobilis with distinct denticles. Cheliped carpus with four ventral setae. Pereopod-1 basis with two long setae, ischium with one seta, dactylus with proximal seta, unguis equal to dactylus. Uropod exopod bisegmented.

Etymology. ‘Chingilingi’ in Ghanaian slang means slim or slender and refers to the most slender body of this species of all the tanaidaceans in the collection.

Description of female. Body ( Fig. 7 A–C) length 1.7 mm (holotype 1.8; others 1.3–2.5 mm), five times as long as wide; cephalothorax 20% of the total body length, not longer than first three pereonites combined, with two pairs of simple setae: posteriorly and anteriorly; eyes with visual elements; pereon half of the total body length; pereonite-1 shortest, 0.3 times as long as wide, pereonite-2 similar in length to pereonite-3, 0.4 times as long as wide, pereonites 4 and 5 longest, 0.5 and 0.6 times as long as wide respectively, pereonite-6 similar in length to pereonite-1; all pereonites with pair of lateral setae; pleon similar in length to cephalothorax, with five pleonites, all similar in length and with one or two pairs of lateral setae; pleotelson 0.3 times as long as wide, with one lateral and one posterior pair of setae.

Antennule ( Fig. 8 A) of four articles – three long and one minute. Article-1 three times as long as wide, with three penicillate setae and two simple setae at midlength and three penicillate and one simple setae distally; article- 2 0.3 times as long as article-1, with two distal simple setae; article-3 half as long as article-1, naked; distal article with three simple setae, a penicillate seta and aesthetasc.

Antenna ( Fig. 8 B) with six articles (article-1 not figured); article-2 0.8 times as long as wide, with strong seta; article-3 similar in length to article-2, with spine; article-4 with one simple and one penicillate setae at midlength, and two simple and two penicillate setae distally; article-5 with simple seta at midlength; article-6 minute, with four simple setae.

Mouthparts. Labrum ( Fig. 8 C) hood-shaped, finely setose. Left mandible ( Fig. 8 D) with wide crenulated lacinia mobilis; incisor with five denticles; molar broad ( Fig. 8 D’) with crenulation and short setae distally. Right mandible ( Fig. 8 E) incisor bifid, with crenulated dorsal margin. Maxillule endite ( Fig. 8 F) with eight distal spines, outer margin with tufts of setae; palp ( Fig. 8 G) with two distal setae. Maxilla ( Fig. 8 H) ovoid, naked. Labium ( Fig. 8 I) bilobed, distally setose.

Maxilliped ( Fig. 8 J) basis with two distal setae; endite ( Fig. 8 J’) with two large and one short, robust distal spines, no distal setae observed (probably broken off), laterally with fine setae; palp article-1 naked; article-2 0.8 times as long as wide, with four inner setae and one short seta on outer margin; article-3 1.4 times as long as wide, with six inner setae; article-4 1.8 times as long as wide, with seven distal setae.

Epignath ( Fig. 8 K) elongate, distally setose.

Cheliped ( Fig. 9 A) basis posterior margin not reaching pereonite-1, 1.3 times as long as wide, with simple medial seta; merus triangular, with simple ventral seta; carpus 1.7 times as long as wide, 1.2 times as long as basis, with four ventral setae and three dorsal setae (one proximally, two distally); propodus 1.2 times as long as wide, with two minute setae; fixed finger as long as propodus, with two ventral setae, cutting edge with five teeth and three simple setae; dactylus with simple seta proximally.

Pereopod-1 ( Fig. 9 B) basis 6.3 times as long as wide, with one simple and one penicillate dorsal setae proximally; ischium with one ventral seta; merus 1.3 times as long as wide, naked; carpus 2.3 times as long as wide, 1.5 times as long as merus, with long dorsodistal seta and two short subdistal setae; propodus six times as long as wide, with two simple setae dorsally and ventral seta; dactylus, little longer than unguis, with dorsal seta; dactylus together with unguis 0.9 times as long as propodus, unguis with spinning-pore ( Fig. 9 B’).

Pereopod-2 ( Fig. 9 C) basis 6.6 times as long as wide, with two dorsoproximal penicillate setae; ischium with ventral seta; merus 1.6 times as long as wide, with ventral seta; carpus 2.8 times as long as wide, 1.5 times as long as merus, with two distal spines and simple seta; propodus 4.6 times as long as wide, 1.2 times as long as carpus, with strong ventral seta and simple dorsal seta; dactylus together with unguis 0.8 times as long as propodus.

Pereopod-3 ( Fig. 9 D) basis 6.7 times as long as wide, with long penicillate seta; ischium with simple ventral seta; merus 1.7 times as long as wide, with robust simple ventrodistal seta; carpus 2.8 times as long as wide, 1.4 times as long as merus, with two simple dorsodistal setae and robust ventrodistal seta; propodus 5.6 times as long as wide, with simple dorsal seta, row of microtrichia on dorsal margin and strong simple ventral seta.

Pereopod-4 ( Fig. 9 E) basis 4.7 times as long as wide, with two penicillate midventral setae; ischium with two ventral setae; merus 1.8 times as long as wide, with two ventral spines; carpus 2.6 times as long as wide, 1.4 times as long as merus, with two ventrodistal spines; propodus 4.5 times as long as wide, with two ventrodistal setae and three dorsodistal setae; dactylus together with unguis 0.8 times as long as propodus.

Pereopod-5 ( Fig. 9 F) basis 4.3 times as long as wide, with two penicillate midventral setae; ischium with two ventral setae; merus three times as long as wide, with two ventrodistal spines; carpus 2.1 times as long as wide, subequal to merus, with three distal spines; propodus 4.8 times as long as wide, with two ventral spines and three dorsodistal setae, along dorsal margin with microtrichia; dactylus together with unguis 0.6 times as long as propodus.

Pereopod-6 ( Fig. 9 G) basis 3.2 times as long as wide, with simple ventral seta and two penicillate setae dorsally; ischium with two ventral setae; merus 2.4 times as long as wide, with two ventrodistal strong setae; carpus 1.5 times as long as wide, 0.8 times as long merus, with two distal spines; propodus 3.6 times as long as wide, with three dorsodistal setae and ventrodistal seta, along dorsal margin covered with microtrichia; dactylus fused with unguis, 0.6 times as long as propodus, with microtrichia.

Pleopod ( Fig. 9 H) basis with lateral seta; endopod with inner seta at midlength and outer row of ten setae; exopod with outer row of 16 setae; all setae plumose.

Uropod ( Fig. 9 I) basis naked; endopod with four segments, segments 1 and 2 each with two simple setae and penicillate seta; segment-3 with long simple seta; segment-4 with two penicillate setae; exopod with two segments, as long as endopod segment-1, both segments with simple seta.

Distribution. The species is known from three stations from Lophelia reef, from the depth range 375– 386 m.

Remarks. The presence of eyes, antennules composed of four articles, maxillipedal basis with two setae at the palp insertion, maxillipedal endite with three flat setae, cheliped merus having one seta, uropodal endopod and exopod composed of four and two segments, respectively, place this new species within the leptocheliid genus Bathyleptochelia . A character that is near-invariant in the leptocheliids and present in the other Bathyleptochelia species—the presence of a large lateral seta on the maxilliped endites—was not observable in the specimens due to poor orientation and obscuration of the structures.

Prior to our study, Bathyleptochelia contained two species, B. oculata Larsen, 2003 found associated with cold-seeps in the Gulf of Mexico and B. selvagema Larsen, 2012 known from off Selvagem Island (Macaronesia). Bathyleptochelia chingilingi sp. nov. can be distinguished from both its congeners by having two setae on the ischia of pereopods 4–6, a bisegmented uropodal exopod, and uropodal endopod with segments 1–2 distinctly longer than segments 3–4.

Figures

FIGURE 7. Bathyleptochelia chingilingi sp. nov., holotype female. A, C, body dorsal view; B, body lateral view. Scale bar: 1 mm.

FIGURE 8. Bathyleptochelia chingilingi sp. nov., female. A, antennule; B, antenna; C, labrum; D, left mandible incisor; D’, molar process; E, right mandible incisor; F, maxillule endite; G, maxillule palp; H, maxilla; I, labium; J, maxilliped; J’, maxilliped endite; K, epignath. Scale bar: 0.1 mm.

FIGURE 9. Bathyleptochelia chingilingi sp. nov., female. A, cheliped; B, pereopod- 1; B’, pereopod- 1 dactylus with spinningpore; C, pereopod- 2; D, pereopod- 3; E, pereopod- 4; F, pereopod- 5; G, pereopod- 6; H, pleopod; I, uropod. Scale bar: 0.1 mm.