Edotia tangaroa Brandt & Bruce, 2006, sp. nov.

Edotia tangaroa sp. nov. (Figs 1–5)

Material examined: All western Ross Sea. Holotype female: Ψ (ovig. 9.0 mm), 72°18.92’S, 170°21.66’E, 12 February 2004, 130 m, grab, TAN0402/94, RV Tangaroa (NIWA 25028). Paratypes: ♂ (11.0 mm), Ψ (7.8 mm), 72°18.92’S, 170°21.66’E, 12 February 2004, 130 m, grab, TAN0402/94, RV Tangaroa (NIWA 17929). Ψ (ovig. 9.5 mm), 71°31.80–31.41’S, 170°06.66–06.79’E, 191–220 m, Ross Sea, 17 February 2004, TAN0402/94, RV Tangaroa (NIWA 17928). Ψ (ovig. 8 mm), 72°18.5’S, 170°26.8’E, 235 m, Ross Sea, 12 February 2004, Rauschert dredge, H­out 4, RV Italica, (ZMH 41221). 6 mancas I (4 at 3.0, 2 at 3.5 mm), 2 Ψ (ovig. 7.5, 8.0 mm), 4 ♂ (8.0, 8.2, 9.2, 10.0 mm), 72°17.0’S, 170°13.1’E, 316 m, Ross Sea, 16 February 2004, Rauschert dredge, H­in 3, RV Italica, (ZMH 41222). 2 mancas I (2 at 3.0 mm), 1 manca II (3.5 mm), ♂ (10.2 mm), 72° 17.2S, 170°17.9’E, 84 m, Ross Sea, 16 February 2004, Rauschert dredge, H­in 5, RV Italica (ZMH 41223). 2 mancas II (4.0, 4.5 mm), 2 Ψ (ovig. 8.0, 9.0 mm), 2 ♂ (9.2, 10.0 mm), 73°22.7’S, 170°06.9’E, 410 m, Ross Sea, 18 February 2004, Rauschert dredge, C 2, RV Italica (ZMH 41224).

Diagnosis

Eyes situated on frontolaterally directed, tuberculate protrusions; head with one pair of dorsal tubercles at mid­length and one pair at distal margin, almost cauliflower shaped; dorsal surface of body with small blunt tubercles; pleotelson with straight lateral margins except for blunt, apically acuminate tubercles. Antenna 1 longer and stouter than antenna 2. Bases of pereopods dorsally with small blunt spines.

Description (Figs 1–4)

Paratype female. Pereonites all very similar in length 4 longest and widest (see Fig. 1). Pereonites 5–7 becoming progressively narrower. Coxae of pereopods 1–7 dorsally visible, delimited by faint sutures, laterally rounded. Dorsal surface of body with blunt tubercles, except for frontal part of pleotelson. Pleotelson lateral margins straight, apex tapered at three­quarters length to form rounded point. Uropods slightly shorter than pleotelson medial length.

Antenna 1 (Fig. 2 A) consisting of 3 peduncular and 3 flagellar articles; peduncle article 1 longest, proximally broadest, article 2 slightly shorter than 1, about as long as article 3, article 3 with 1 distal simple seta; all peduncular articles covered with short setae; flagellum article 1 forming short ring, with 2 lateral plumose setae; second flagellum article almost as long as peduncle article 2, with 3 distal simple setae and single aesthetasc; terminal flagellar article small and short, knob­like, with 4 aesthetascs.

Antenna 2 (Fig. 2 B) consisting of 5 peduncular and 1 flagellar articles; article 1 broadest (damaged during dissection), article 2 slightly narrower than article 1 but as long as article 3, articles 2 and 3 with 1 lateral small spine and 1 distolateral simple seta, article 4 slightly longer than article 3, with small lateral spines and 1 distolateral simple seta, article 5 longest, with 3 simple setae and 3 plumose setae. Flagellum of 1 small, short article and 3 simple setae distally, with 3 apical simple setae (broken off).

Mandibles conservative (not illustrated), both sides without palp. Pars incisivae asymmetrical, that of right mandible narrower than left mandible, with 3 strong chitinized teeth; lacinia mobilis of right mandible with 1 strong chitinized cusp, one seta­like structure and some simple basal bristles; pars molaris stout, with broad grinding surface and indented lower margin. Pars incisiva of left mandible with 4 chitinized cusps, lacinia mobilis with 4 teeth, smaller than pars incisiva, with 2 seta­like structures and some simple bristles. Pars molaris as in right mandible.

Maxilla 1 mesial lobe (Fig. 2 E) with 1 strong setulated seta (damaged in this specimen); lateral lobe with 9 strong denticulated robust setae (see detail in Fig. 2 C).

Maxilla 2 lateral lobe (Fig. 2 D) with 4 strong, densely serrate setae of different lengths; mesial lobe with 4 stout serrate, short and broad setae, proximally on broader base, distinctly serrate in upper two­thirds; mesial lobe with 2 rows of setae, one row with 7 setulated stout and long setae and one with 4 serrated more slender setae.

Maxilliped (Fig. 2 C) palp 3­articulated, palp article 1 shortest, almost ring­like, article 2 trapezoidal, article 3 largest and distally rounded; palp articles mesially with short simple setae; epipod oval, distally narrower than proximally, with 2 simple setae and small setules, reaching to distal margin of palp article 1; endite long and slender, dorsally and mesially bearing 7 slender plumose setae, with 1 mesial coupling hook.

Pereopod 1 (Fig. 3 A) basis longer than combined lengths of ischium, merus and carpus, dorsal margin with short blunt spines, ventral margin with setules and distolateral cuticular comb; ischium about 0.4 times as long as basis, ventral margin with setules and 5 simple setae; merus 0.8 times as long as ischium, distodorsal margin with simple seta and ventral margin with 5 simple setae as well as setules; carpus short, distoventral margin with 1 strong sensory robust seta and 5 simple setae; propodus subchelate, dorsal margin with 10 simple setae and 1 distodorsal plumose seta, ventral margin with 11 simple setae and 2 basal sensory setae, dorsally and ventrally some simple setules as well as row of cuticular combs in upper two­thirds of propodus; dactylus (excluding claws) about 0.5 times as long as propodus, with 2 robust distal claws, dorsal claw 3 times as long as ventral claw, with 2 simple setae between claws, ventral margin with simple seta and cuticular comb present at base of ventral claw, dorsal and ventral margins with simple setae and short setules, with cuticular combs in distal half.

Pereopod 2 (Fig. 3 D) similar to pereopod 1, dorsal and ventral margins of all articles with simple setules; ischium almost half as long as basis, slender; merus similar to that of pereopod 1 distodorsal margin with 3 long simple setae, ventral margin with 3 long setae; carpus quadrangular, about as long as merus, with fewer setules, without stout sensory seta, ventral margin with 7 simple setae; propodus subchelate, ventral margin with 15 simple setae and 1 basal robust sensory setae and cuticular combs, dorsal margin with 9 simple setae and 1 distodorsal plumose seta; dactylus (excluding claws) about 0.5 as long as propodus.

Pereopod 5 (Fig. 3 C) longer and more slender than pereopods 1, 2 and 7. General appearance of setation of articles similar to other pereopods, dorsal and ventral margins with simple setules; basis longest article, almost twice as long as propodus, dorsal margin with 5 small blunt spines and 3 simple setae, ventral margin with 2 simple setae; ischium and propodus about subequal in length, ischium ventral margin with 3 simple setae; merus about as long as carpus, dorsal margin distally protruded, ventral margin with 2 simple setae; carpus ventral margin with 4 simple setae; propodus dorsal margin with 4 dorsal simple setae and 3 distodorsal plumose setae, ventral margin with 10 simple setae; dactylus similar to that of pereopods 2 and 7, without cuticular comb. Pereopod 6 (not illustrated) similar to pereopod 5.

Pereopod 7 (Fig. 3 B) longer and more slender than pereopods 1–4. General appearance of setation of articles similar; basis, ischium and propodus long and slender, basis longest, dorsal margin with 1 blunt spine, 9 dorsal and lateral simple setae, ventral margin with row of 11 simple setae, 5 dorsal and 4 ventral setules ischium, dorsal margin with numerous simple setules and 3 distodorsal and 5 ventral simple setae; merus about as long as carpus, dorsal margin distally protruded, with 2 distodorsal, 1 lateral and 5 ventral simple setae; carpus with 2 dorsal, 4 lateral and 4 ventral simple setae; propodus with 6 dorsal simple setae, 1 distodorsal plumose seta, 8 lateroventral or ventral simple setae and 1 distoventral deeply incised sensory seta; dactylus similar to pereopods l–4, but dorsal and ventral margins with fewer simple setae, without cuticular comb.

Pleopod 1 (Fig. 4 A) sympod with 3 simple and 3 coupling setae; exopod 0.95 endopod length, laterally, distally and mesiodistally with plumose setae; endopod mesially and distally with plumose setae. Mesial margin of exopod parallel to endopod.

Pleopod 4 (Fig. 4 B) sympod almost quadrangular; endopod 0.8 exopod length, with 2 distal plumose setae; exopod with acute tip, without setae.

Pleopod 5 (Fig. 4 C) sympod almost quadrangular; endopod 0.9 exopod length, with 1 distal plumose seta, exopod without setae.

Uropod (Figs 1, 4 D) covered with tubercular structures on mesial surface, outer covered with simple setae; distocaudal margin with 5 plumose setae.

Male. Eyes situated on broader protrusions than in female. Body with frontomedial protrusions smaller than in holotype and paratype females, less tubercles on the dorsal side of the body than paratype female.

Antenna 2 distally with simple setae, fewer setules than in female paratype. Pereopod 1 of similar shape to female, but with fewer setae and shorter basis.

Pleopod 1 very similar to that of female, except exopod with only lateral and distal plumose setae. Pleopod 2 with appendix masculina 1.4 as long as endopod, distal one­third abruptly narrowed; endopod long and slender; exopod 0.8 as long as endopod, but 1.5 as broad as endopod.

Var ia t io n: The paratype male (Fig. 5 A, C–F) and paratype female (Figs 1–4) have fewer dorsal tubercles on the head, and eyes on more blunt protrusions than in the female holotype (Fig. 5 B).

Remarks

E. tangaroa sp. nov. can be readily identified by two characters: the blunt tubercles, which are irregularly placed over the dorsal surface of the body and by antenna 1, which is slightly longer and more stout than antenna 2. In this respect, E. tangaroa is most similar to E. pulchra Brandt, 1990, as the latter is the only other species characterised by tubercular ornamentation on the apical part of the pleotelson. In comparison, the lateral margins of the pleotelson of E. pulchra are straight, and the pleotelson shorter than that of E. tangaroa, and this species also bears blunt broad spines dorsomedially on all pereonites as well as a pair of two blunt spines on the head, which are absent in E. tangaroa.

Distribution

Known only from the Ross Sea; at depths of 84 to 410 metres.