Tanaella kommritzia Larsen & Shimomura, 2007, n. sp.

Tanaella kommritzia n. sp.

(Figs 14–16)

Material examined. Holotype, non-ovigerous female (KMNH IvR 700.192), Station TS-4, 15 November 2003, 35°11.409’–35°11.460’, 140°52.629’– 140°53.441’E, off Boso Penisula, 444–574 m, muddy sand. Paratypes, 1 non-ovigerous female (KMNH IvR 700.193)(dissected), same locality; 2 non-ovigerous females (KMNH IvR 700.194, 700.195), same locality; 1 non-ovigerous female (KMNH IvR 700.196), Station 8, 26°26.63’N, 127°33.04’E, Northwest of Cape Zanpa, Okinawa, 654– 635 m, sand, 27 May 2006; 2 nonovigerous females (KMNH IvR 700.197, 700.198), Station KG-2, 17 November 2003, 34°58.192’– 34°58.398’N, 140°05.188’– 140°05.115’E, off Boso Peninsula, muddy sand, 186– 169 m.

Diagnosis. Female. Antennule article 2 half the length of article 1. Cheliped fixed finger with pronounced serration. Cheliped dactylus without depression and processes. Uropods stout and long (longer than combined length of pleotelson and two pleonites), particularly the basal article (longer than pleotelson).

Etymology. Named after the tanaidacean expert Dr. J. Gurrero-Kommritz, Zoological Museum Hamburg.

Description (body of holotype, appendages of dissected paratype).

FEMALE.

Body (Figs. 14 A, 15A). Body length 3.2 mm. Cylindrical, nine times longer than broad.

Cephalothorax. As long as combined length of pereonites 1 and 2.

Pereonites. Wider than long. Pereonite 1 shorter than pereonites 5. Pereonite 2 and 3 subequal. Pereonite 4 and 5 subequal, shorter than pereonites 2 and 3. Pereonite 6 shorter than other pereonites.

Pleon. All pleonites subequal and with pleopods. Pleotelson shorter than combined length of three pleonites.

Antennule (Fig. 14 B). With five articles. Longer than cephalothorax. Article 1 marginally shorter than rest of antennule, with one simple and two setulose distal setae. Article 2 half the length of article 1, with one simple subdistal seta. Article 3 half as long as article 4, with one simple subdistal seta. Article 4 length half of article 2, with six simple distal setae and one aesthetasc. Article 5 minute and obscured by ring of distal setae on article 4.

Antenna (Fig. 14 C). With six articles and fusion line, 0.8 times as long as antennule. Article 1 not broader than following articles, naked. Article 2 longer than article 1, with one simple dorsodistal seta. Article 3 shorter than article 2, with one dorsodistal seta. Article 4 with clear fusion line, longer than other articles, with two simple and three setulated distal setae. Article 5 longer than article 2, with two distal setae. Article 5 minute, with four distal setae and one aesthetasc.

Mouthparts. Labrum (Fig. 14 D) almost square, naked. Left mandible ( Fig. 14 E) lacinia mobilis broad, bifurcate, incisor broad with four denticles. Right mandible (Fig. 14 F) incisor square, with proximal spine. Labium (Fig. 14 G) simple M-shaped. Maxillule (Fig. 14 H) endite with eight distal spiniform setulose setae. Maxilla (not recovered). Maxilliped (Fig. 15 B) endites with weak process on distal margin and no setae, outer corners with weak serration. Basis only marginally wider than endites. Palp article 1 with one outer seta. Article 2 with three inner setae of which one is bipinnate. Article 3 with four inner setae of which two are setulated. Article 4 with four bipinnate and one simple distal setae. Epignath (Fig. 14 I) slender, naked.

Cheliped (Fig. 15 C). Basis divided equally by sclerite, shorter than carpus. Merus triangular with one seta. Carpus shorter than propodus, with two ventral and two dorsal seta. Propodus with one seta between fixed finger and dactylus, fixed finger with pronounced serration (at least seven acute spines), with two ventral setae and three on inner margin. Dactylus with one small spiniform seta on inner margin.

Pereopod 1 (Fig. 16 A). Coxa with one seta. Basis longer than three succeeding articles together, with one dorsoproximal setulated seta. Ischium with one ventral seta. Merus longer than carpus, widening distally and with one spiniform ventral seta. Carpus half as long as propodus, rectangular, with ventrodistal spiniform seta and one long dorsodistal spiniform seta. Propodus longer than half of basis, ventral margin smooth, with one spiniform ventrodistal spiniform seta and dorsodistal spine. Dactylus and unguis combined shorter than propodus.

Pereopod 2 (Fig. 16 B). As pereopod 1 except: basis naked; carpus with two dissimilar spiniform ventrodistal seta, one long spiniform dorsodistal seta and one modified seta one serrated distal setae; dactylus with small seta at unguis insertion.

Pereopod 3 (Fig. 16 C). As pereopod 2 except: coxa naked; merus with one spiniform ventral seta and one simple seta; dactylus naked.

Pereopod 4 (Fig. 16 D). Without coxa. Basis slightly wider than on pereopod 1–3, with two setulated seta. Ischium with two setae. Merus with two spiniform ventrodistal setae, about as long as carpus. Carpus with one small modified seta and four spiniform distal setae. Propodus with three spiniform distal setae and dorsal spine. Dactylus and unguis not fused, longer than propodus. Dactylus with two parallel rows of small setules.

Pereopod 5 (Fig. 16 E). As pereopod 4 except: carpus with three spiniform distal setae; propodus with two spiniform distal setae, dorsal spine, and dorsomedial setulose seta.

Pereopod 6 (Fig. 16 F). As pereopod 4 except: basis naked; propodus with four spiniform setae and paired dorsal spines.

Pleopods (Fig. 14 J). Well developed. Peduncle rhomboid. Exopod with 14 plumose setae and basal seta, gap between basal seta and others. Endopod with eight plumose setae.

Uropods (Fig. 14 K). Basal article as long as endopod, with two simple distal setae near exopod process. Exopod completely reduced to a small process. Endopod with one simple and one setulose medial setae, distally with four long and two short simple setae and one setulate seta.

Remarks. Tanaella kommritzia is easily recognized from other Tanaella by the long powerful uropods (particularly the basal article) being longer than combined length of pleotelson and two pleonites.

Tanaella was recently revised (Larsen & Heard 2004) but new species appear in all major deep-sea surveys. This genus is cosmopolitan and is probably present in all habitats over 100 meters depth. A key to the genus is given by Gurrero-Kommritz & BłaŻewicz-Paszkowycz (2004).