Tanaella eltaninae Guerrero-Kommritz & Blażewicz-Paszkowycz, 2004, sp. nov.

Tanaella eltaninae sp. nov. (Figs 1­3)

Material examined: holotype, USNM 1020439, female, 2.17 mm, Eltanin cruise 8, sta. 573, 55°11`S 024°10`W – 55°13`S 024°05`W, Menzies Trawl, depth 3978–4008 m; 16 April 1963. Paratype: USNM 1020440, female, 3.02 mm, Eltanin, cruise 21, sta. 267, 56°32`S 119°20`W – 56°30`S 119°27`W, Menzies Trawl, depth 4740–4742 m; 23 December 1965, (dissected).

Diagnosis: cheliped massive, without proximal tubercle in inner margin of dactylus. Maxilliped endites with tubercle. Labium narrow. The basis of pereopods 1–3 shorter than remainder of the articles combined. Pereopods 4–6 with ventral margin of propodus not serrated. Uropod as long as pleotelson, composed of uni­articled endopod.

Description: non­ovigerous female. Body (Figs. 1 a, b) elongate, about six times longer than broad, slightly flattened dorsoventrally.

Cephalothorax (Fig. 1 a, c) triangular, shorter than pleon, posterior end twice as wide as anterior end.

Pereon with first pereonite as long as sixth, second slightly longer than third and third to fifth subequal in length.

Pleon as wide as pereon; first three pleonites subequal in length and shorter than fourth and fifth. Pleotelson as long as last four pleonites together, pentagonal, apex rounded.

Antennula (Fig. 2 a) four­articled. First article longest, and equal in length to articles 2– 4, with two short, subdistal setae. Second article with two distal setae. Third article shortest, with three setae (one minute). Fourth article narrowest, with six terminal setae and one aesthetasc.

Antenna (Fig. 2 b) six­articled. First article, small and partly fused with cephalothorax (not illustrated), second article triangular in shape with three comb setae and one distal long seta. Third article square with one long distal seta. Fourth article longest, equal in length to articles 1–3 combined, dorsal margin with four comb setae, three long and two minute distal setae. Fifth article with one distal seta. Sixth article shortest, with four long and one short setae.

Mouthparts: Labrum (Fig. 2 c) hood­like with a finely setulose margin. Mandible (Figs. 2 d, e) well sclerotized; right mandible incisor pointed with three teeth; left mandible incisor with three blunt teeth, lacinia mobilis flat and blunt; seven terminal teeth on the molar process. Maxillula (Fig. 2 f) endite, inner margin with seven combs of setules, and nine distal spines (three bipinnate, five simple, and one very slim). Palp as long as endite with one long and one short terminal seta. Maxilla (Fig. 2 g) triangular, naked. Labium (Fig. 2 h) composed of two triangular lobes with one spiniform seta and many setules on apical margin. Maxilliped (Figs. 2 i, i`) basis fused, one seta near insertion of palp; endites rectangular, free. Distal part of each endite with one tubercle at inner margin and one medial seta; outer margin with a row of setules descending to the base. Palp four­articled. First article with combs of fine setules and one comb of relatively strong setulae on outer margin. Second with two combs of setulae and one simple, distal seta on outer margin. Third article with three inner setae and numerous combs of setules. Fourth article with four inner and two terminal setae (one very thin). Epignath (Fig. 2 j) falciform with a lobe on the proximal end and a seta on it distal end.

Cheliped (Fig. 2 k) attached to cephalothorax by sidepiece. Basis strong. Merus wedgeshaped, naked. Carpus with two medial ventral setae and one dorsal terminal seta. One tubercle near insertion of propodus. Propodus twice as long as broad, fixed finger with two ventral setae (the distal seta extends over the tip of the fixed finger) and three dorsal setae near cutting edge. Cutting edge with five teeth. One depression on proximal margin. Dactylus with two small teeth at the mid­ventral part of the chela.

Pereopod 1 (Fig. 3 a) coxa with a simple seta. Basis as long as carpus and propodus combined, with one fine seta on dorsal margin and a longitudinal row of setules ventrally. Ischium short, with one ventral seta. Merus triangular with one strong and fine distal setae. Carpus subequal in length to merus, with numerous combs of setules and three strong setae (two short and one long). Propodus nearly 1.5 times as long as carpus, with two rows of spinules ventrally, a row of setules dorsally, and one strong distal seta. Dactylus slightly longer than unguis. Unguis sharp with one setula in the middle.

Pereopod 2 (Fig. 3 b) as pereopod 1 except basis with two fine setae dorsally and no setulae line ventrally, carpus with two long and one short strong terminal setae, unguis subequal to dactylus, without setulae.

Pereopod 3 (Fig. 3 c) as pereopod 2 except basis with one setulose seta dorsally; and a minute distal seta on dactylus.

Pereopod 4 (Fig. 3 d) without coxa. Basis long and naked. Ischium short, with one seta. Merus with two distal setae. Carpus slightly longer than merus, with one longitudinal ventral row of setules and five terminal setae: three strong and elongate, one short and one minute. Propodus slightly longer than carpus, with rows of thin setules ventrally, and three strong distal setae, one short and two long (slightly shorter than dactylus). Dactylus with ventral groove bordered by fine spinules. Unguis sharp, 2.5 times shorter than dactylus.

Pereopod 5 (Fig. 3 e) without coxa. Proportions of basis, ischium, merus, carpus, and propodus as in pereopod 4. Basis naked. Ischium with two setae. Merus triangular, with two strong setae. Carpus with four strong distal setae and a fine short one. Propodus covered with many combs of fine setules, and three strong terminal setae. Dactylus with a ventral groove, and bordered by fine spinules. Unguis sharp, slightly longer than dactylus.

Pereopod 6 (Fig. 3 f) without coxa. Proportions of basis, ischium, merus, carpus and propodus as in pereopod 4. Basis naked. Ischium with one seta. Merus triangular, with two distal setae. Carpus with four distal setae and many combs of setules. Propodus covered with many rows of setules. Four strong, and rather long terminal setae. Dactylus as in pereopod 5. Unguis sharp, slightly longer than dactylus.

Pleopods absent.

Uropods (Fig. 3 g) uniramous. Basal article short, with one tubercle and a long seta. Endopodite one­articled with two long terminal setae and a lateral long one.

Ovigerous female, males and mancas unknown.

Etymology: named after the research vessel Eltanin.

Remarks: the species resembles Tanaella paraforcifera, but it differs in the relative length of the body: T. paraforcifera is about five times as long as wide, whereas T. eltaninae is about 6 times as long as wide. The basis of pereopods 1–3 of T. paraforcifera are longer than the remainder of the pereopod articles combined, while the basis of T. eltaninae is shorter than the remainder of the pereopod. The labium is elongate and narrow in T. paraforcifera, and short and wide in T. eltaninae. On the carpus of pereopod 1 there are two setae in T. paraforcifera and three setae in T. eltaninae.