Paratanais incomptus, Bird & Bamber, 2013

BIRD, GRAHAM J. & BAMBER, ROGER N., 2013, New littoral, shelf, and bathyal Paratanaidae (Crustacea: Peracarida: Tanaidacea) from New Zealand, with descriptions of three new genera, Zootaxa 3676 (1), pp. 1-71 : 38-39

Paratanais incomptus sp. nov.

Figures 22 –24, 36G, T, V–W

Material examined. Holotype: non-ovigerous ♀, NIWA 85619 , Stn D. 121, Reserve Bank, Chatham Rise, 210 m, 43.2750°S, 177.1750°E, 11 October 1963.

Paratypes: one non-ov. ♀, NIWA 62675 , Stn A. 897, Reserve Bank, Chatham Rise , 221 m, 43.2833°S, 177.2833°E, 8 September 1963 ; one non-ov. ♀, NIWA 62678 , Stn A. 899, Reserve Bank, Chatham Rise , 241 m, 43.4583°S, 177.1833°E, 8 September 1963 ; one manca-III, two non-ov. ♀♀, NIWA 14083 , Stn A. 900, Reserve Bank, Chatham Rise , 251 m, 43.3667°S, 177.0583°E, 8 September 1963 ; four non-ov. ♀♀ (one partly dissected on microslide) NIWA 14047 ), Stn D. 121, details as for holotype; five non-ov. ♀♀, CR.23500, Stn O. 632/BS.886, eastern slope of Wanganella Bank, Norfolk Ridge , 422–437 m, 32.5775°S, 167.6733°E, 29 January 1981 , R. V. Tangaroa ; one non-ov. ♀, NIWA 14021 , Stn S. 890C, off Hokitika, West Coast, South Island , 298 m, 42.5017°S, 170.5317°E, 12 April 1963 .

Other material: one non-ov. ♀, CR.23501, Stn BS.904, King Bank, NE of Great Island ( Three Kings Islands ), 128 m, bryozoans and shell, 33.9500°S, 172.3167°E, 1 February 1981, R. V. Tangaroa .

Diagnosis. Female: with carapace entire. Pleon shorter than pereonites 5–6 combined. Antenna article-2 not expanded, with simple mid-inferior seta, with small superolateral seta; article-3 superodistal spine acute. Mandible lacinia mobilis with crenulated distal margin. Maxilliped endite spines conical; palp article-2 with unspecialised superoproximal seta. Pereopods 4–6 ischium setae short; merus without seta; carpus spines well developed, finely serrate. Uropod about as long as pleotelson, exopod one-segmented; endopod two-segmented.

Male: unknown.

Etymology. From Latin adjective incomptus , ‘unadorned’, referring to its rather non-descript morphology.

Description. Non-ovigerous female: Habitus ( Fig. 22A ) slender, up to 7.5 times ltb, length 1.5–3.7 mm. Cephalothorax pear-shaped, 1.2 times ltb, as long as pereonites 1–2 combined. Pereon 59% of body length, pereonites 2–5 of similar length, with almost straight lateral margins; pereonites 0.5, 0.8, 0.7, 0.8, 0.7 and 0.6 times as long as broad respectively; pereonite-1 with four distolateral and distomedial setae. Pleon shorter than pereonites 5–6 combined, 16% of body length, 1.1 times ltb. Pleotelson ( Fig. 22B–C ) as long as pleonites 4–5 combined, about half as long as broad, with protruding rounded posterior margin (dorsal view).

Antennule ( Fig. 22D, G ) 0.9 times as long as cephalothorax; article-1 about 45% of total length, twice as long as broad, article-2 slightly shorter than broad, lateral seta long; article-3 0.6 times as long as article-2, shorter than broad; article-4 as long as articles 2–3 combined; with cap-like segment; terminal setae of one PSS, five unequal simple setae and an aesthetasc. Antenna ( Figs 22E , 36V ) 0.75 times as long as antennule; article-2 subrectangular, slightly wider distally, 1.7 times ltb, with lateral seta, and small inferior seta just distal to mid-length, superodistal seta shorter than article-3; article-3 shorter than broad, with articulated or non-articulated superodistal spine acute; article-4 articulation with article-3 oblique (directed slightly laterally) as long as article-2, three times ltb; article-5 just over half as long as article-4, 2.6 times ltb; article-6 with four terminal setae.

Labrum ( Fig. 23A ) typical. Mandibles ( Fig. 23B, C ) left mandible lacinia mobilis very broad, with six or seven processes, molar with about six spines; right incisor with weakly bifid tip. Labium ( Fig. 23D ) medial lobe with seta. Maxillule ( Fig. 23E ) endite with eight (?) terminal spines. Maxilla not recovered. Maxilliped ( Fig. 23F–H , 36T ) bases about 1.8 times ltb, unfused in distal third, medial seta just reaching endite margin. Epignath not recovered.

Cheliped ( Fig. 23J–K ) basis 1.8 times ltb, with posterior lobe not much smaller than anterior part; merus typical; carpus subovate, 1.3 times longer than basis, 1.7 times ltb; chela as long as, but narrower, than carpus, propodus 2.3 times ltb, palm slightly narrower distally, 1.7 times ltb, medial comb with three spines; fixed finger distal tooth large, bifid; dactylus with peg-like spine on inferior margin.

Pereopod-1 (Fig. 24A) basis four times ltb; merus about three times ltb, with small supero- and inferodistal setae; carpus two-thirds as long as merus, twice as long as broad, with three distal setae; propodus about twice as long as carpus, 4.4 times ltb; dactylus-unguis combined as long as propodus. Pereopod-2 (Figs 24B, 36G,W) 0.75 times length, and stouter than pereopod-1; basis 2.8 times ltb; merus 1.4 times ltb, with two inferodistal spines; carpus subrectangular, longer than merus, spines finely serrate; propodus just longer than merus and carpus combined, with one superodistal seta; dactylus-unguis combined as long as propodus. Pereopod-3 (Fig. 24C) similar to pereopod-2, but basis slightly shorter.

Pereopod-4 (Fig. 24D–F) basis robust, larger than pereopods 1–3 combined, 2.7 times ltb, with superior groove and proximal seta; merus typical, with unequal spines; carpus subrectangular, longer than merus, twice as long as broad; propodus longer than carpus, superodistal spine almost as long as dactylus; dactylus-unguis combined less than half length of propodus. Pereopod-5 (Fig. 24G–H) similar to pereopod-4 but basis midlength with two inferior PSS. Pereopod-6 (Fig. 24J–K) typical, similar to pereopods 4–5.

Pleopod ( Fig. 23L ) peduncle longer than broad; endopod twice as long as broad, and with trace of small proximal article, outer margin with 14 plumose setae, medial margin setulate; exopod with ca. 20 plumose setae.

Uropod ( Fig. 22F ) as long as or slightly shorter than pleotelson; peduncle just shorter than broad; exopod onesegmented, 3.2 times ltb, reaching to distal of segment-1 of endopod; endopod two-segmented, 4.2 times ltb, with four long simple setae, and two PSS.

Distribution and ecology. This appears to be a shelf and upper-bathyal species, known from only seven records, extending from the Norfolk Ridge to the Reserve Bank sector of the Chatham Rise, with a single record from off the west coast of South Island, at depths 128– 437m. As for P. hamulus , it has been recorded with bryozoans.

Remarks. Of the previously described NZ Paratanais species ( P. tara and P. paraoa ) Paratanais incomptus sp. nov. is closer to P. paraoa , but has a non-inflated antennal article-2 with a simple inferior seta at mid-length, a

Figures

FIGURE 22. Paratanais incomptus sp. nov. Holotype female [NIWA 85619]: A habitus; B–C pleotelson, dorsal and lateral; D antennule; E antenna; F uropod, lateral. Paratype non-ovigerous female (NIWA 14021): G antennule apex. Scale bar: 1mm for A; 0.5 mm for B, C; 0.25 mm for D–G.

FIGURE 23. Paratanais incomptus sp. nov. Paratype non-ovigerous female [NIWA 14047]: A labrum; B–C left and right

FIGURE 36. A Metatanais sp. antennule, lateral; B Metatanais sp. uropod; C Xeplenois pleon-pleotelson, dorsal and lateral (pleopod & setae omitted), after Bamber 2005; D Penteparatanais pereopod-4 carpus; E Paratanais hamulus pereopod- 5carpus; F Acallocheirus pereopod-2 carpal spines; G P. incomptus pereopod-2 carpal spines; H Aparatanais timutimu maxilliped palp article-2 spine; J A. timutimu cheliped kukri spine: K A. timutimu uropod; L Paratanais caterae cheliped spine; M P. puia uropod; N P.hamulus antenna article-3. O Atemtanais antenna article-3, after Bird 2011; P Atemtanais pereopod-2 carpal spines, after Bird 2011; Q Paratanais caterae pereopod carpal spines; R P.caterae maxilliped palp article-2 spine; S P.