Tanais nuwalianensis, Tzeng, You-Wei & Hsueh, Pan-Wen, 2014

Tzeng, You-Wei & Hsueh, Pan-Wen, 2014, Two new species of Tanaidacea (Crustacea, Peracarida) from Taiwan, Zootaxa 3802 (1), pp. 51-64 : 58-59

Tanais nuwalianensis sp. nov.

( Figs 4–6 , Table 2)

Material examined. Holotype, non-ovigerous female ( NMNS 7214-5), 4.3 mm, Jihuei (23°06’54.9”N, 121°24’16.3”E), eastern Taiwan, intertidal, washing from red coralline alga Jania sp., collected by You-Wei Tzeng, April 18, 2012; allotype, male ( NMNAS 7214-6), 3.2 mm, same as type locality, from Eunice sp. polychaetous worm tube washing, collected by You-Wei Tzeng, March 25, 2011; paratype: one non-ovigerous female ( NMNS 7214-7), 4.2 mm, same as type locality, from red coralline alga Mastophora sp. washing, collected by You- Wei Tzeng, April 18, 2012.

Diagnosis. Female: Antennule five-articled (three main articles and two short distal segments) with six distal aesthetascs; antenna eight-articled (five main articles and three short distal segments). Left mandible lacinia mobilis tooth-like, superior margin with three low serrations; right mandible lacinia mobilis small, peg-like. Pereopod 6 propodus with seven leaf-like setae, four bipinnate setae and two elongate pinnate setae on distal margin. Pleopod basis bears one to three setae on inner margin; uropod ‘four-articled’ (three segments and peduncle).

Description. Holotype ( Fig 4 A): Body seven times as long as wide. Cephalothorax subtriangular, posterolateral margin rounded, about 1/5 of body length, pereonite 1 shortest, pereonite 4 and 5 longest. Pleon about 1/4 of body length; pleonites 1 and 2 subequal in length, a dorsal transverse row of plumose setae present near posterior margin; pleonite 4 distinctly smaller than other three; pleonite 5 fused; pleotelson apex protruding.

Antennule ( Fig 4 C) five-articled, slightly shorter than cephalothorax; article 1 about 1/2 of total length of antennules, with two short lateral bipinnate setae, three distal bipinnate seta, and three distal simple setae; article 2 slightly longer than article 3, with ten distal setae; article 3 with two distal setae; articles 4 and 5 very short, scattered with nine simple setae and five aesthetascs. Antenna ( Fig 4 D) eight-articled; article 2 with two distal setae, much larger than article 3; article 3 short, with one short distal bipinnate seta; articles 4 and 5 more slender than article 3, combined 1/2 total length of antenna, with three and five distal setae, respectively; article 6 to 8 small, with four and seven distal setae respectively.

Labrum ( Fig 4 E) hood-shaped covered by fine setules. Epignath ( Fig 5 B) typical, margins covered with fine setules. Labium ( Fig 4 F) bi-lobed, outer lobes as long as inner, superior margin of both covered by fine setules, outer lobe with ovate process (non-articulated palp). Left mandible ( Fig 4 G) distolateral margin with a distinct concavity, lacinia mobilis ( Fig 4 H) tooth-like with three serrations on superior margin and one adjacent plumose setae. Right mandible ( Fig 4 I) likewise, lacinia mobilis ( Fig 4 J) peg-like and minute, accompanied by one minute plumose seta. Maxillule ( Fig 5 A) endite with seven distal spines and fine setules, superior margin with small denticles; palp with seven long setae. Maxilliped ( Fig 5 C–D) coxa with one inferior seta; basis with two lateral setae, and three long and one short distal setae; endites ( Fig 5 D) distal margin covered by fine setulae, with two simple distal setae and two distomedial hooks; palp ( Fig 5 C) article 1 with one lateral seta; article 2 with six medial setae, one distolateral seta; article 3 with eight medial setae; article 4 with one dorsal seta and twelve distal bipinnate setae.

Cheliped ( Fig 5 E) attached to cephalothorax via sclerite, with triangular insertion to basis, with one superior seta; basis 1.4 times ltb, with one inferodistal seta; merus triangular, with three inferior setae; carpus 1.35 times ltb, five superior and four inferior setae; propodus including fixed finger 1.4 times as long as carpus, fixed finger about 1/2 propodus length, five inferior setae, inner margin with large blunt process and 11setae, two inner margin setae near articulation with dactylus; dactylus slightly longer than fixed finger; both fixed finger distal and dactylus unguis heavily calcified.

Pereopod 1 ( Fig 5 F) longest; coxa with two setae, anterior not bulged; basis 3.4 ltb, with four superior setae; merus about 1/3 length of basis, with one superodistal seta, one lateral seta, and two inferodistal setae; carpus 40% length of basis, with three superior setae and one inferodistal seta; propodus 3.4 ltb, with two superodistal setae and five inferodistal setae; dactylus slightly curved, with one superior seta, unguis half length of dactylus. Pereopod 2 ( Fig 5 G) coxa with two setae; basis 2.8 ltb, with five superior setae and two inferodistal setae; merus about 40% length of basis, with one superodistal seta, two inferior setae, one long inferodistal seta, and two inferodistal spines; carpus with one long superodistal seta; distal margin with six and five spines on outer and inner side respectively; propodus with one superior bipinnate seta, two superodistal setae, one inferior seta, one inferodistal seta, and one row of tiny spinules on inferior margins; dactylus unguis more curved than pereopod 1 dactylus. Pereopod 3 ( Fig 6 A) similar to pereopod 2 but basis with one inferoproximal seta, superior margin with only three seta, merus inferior margin with four tiny spinules, carpus distal margin with seven outer spines and six inner spines, and propodus with two simple superior setae and three inferior setae. Pereopod 4 ( Fig 6 B–C) basis with one row of inferoproximal setulae and one inferodistal seta; merus ventral margin with one row of tiny spinules and two setae, one long inferodistal seta and two inferodistal spines; carpus superior margin with one seta, distal margin with six spines on each side and several row of setulae nearby (see Fig 6 G); propodus superodistal margin with two strong long pinnate seta and one bipinnate seta, inferior margin with two setae and two distal setae, dactylus and unguis fused to a claw with one row of setules on either side. Pereopod 5 ( Fig 6 D–E) similar to pereopod 4 but basis inferior margin with one bipinnate seta and two simple setae, merus inferior margin with two setae, distal with three spines. Pereopod 6 ( Fig 6 F–H) similar to pereopod 5 but basis superior margin with two setae and inferior margin with one seta, merus with one inferior setae and four inferodistal spines, carpus distal margin with six and five spines on outer and inner side respectively, propodus distal margin with one row of six and one smaller leaflike setae, four bipinnate setae and two elongate pinnate seta.

Pleopod 1 (not figured) basis inner margin with three setae, outer margin with 11 setae; endopod inner margin with 17 setae, outer margin with 19 setae and one distal seta; exopod inner margin no seta, outer margin with 42 setae. Pleopod 2 (not figured) similar to pleopod 1, but basis inner margin with two setae and endopod inner margin with 15 setae instead. Pleopod 3 ( Fig 6 I) basis inner margin with one setae, outer margin seven setae; endopod inner margin with 12 setae, outer margin with 21 setae and one distal seta; exopod inner margin no seta, outer margin with 39 setae, all plumose setae. Uropod ( Fig 6 J) peduncle 2.1 ltb, with four distal setae; endopod threesegmented; segment 2 with four distal simple setae and one bipinnate seta; segment 3 with eight distal simple setae and two bipinnate setae.

Male paratype ( Fig 4 B): Similar to female except body more robust, about 3.5 times ltb; cephalothorax about 1/4 of body length; antennule with nine distal aesthetascs; cheliped merus inferior margin with seven setae; pereopod 2 carpus with seven outer spines and six inner spines, pereopod 3 carpus with seven on each side, pereopod 4 carpus with eight outer spines and seven inner spines, pereopod 5 carpus with seven outer spines and six inner spines, pereopod 6 carpus with seven outer spines and six inner spines, propodus distal margin with one row of ten leaf-like setae, four plumose setae and one elongate simple seta.

Etymology. The name is derived from “Nuwalian”, the local Amis aboriginal language for the location of the sampling site, meaning “the most eastern point”.

Type locality. Jihuei, eastern Taiwan.

Distribution. It is only known from type locality.

Remarks. In appearance, the colour patterns of female T. nuwalianensis are not much different from that of congeners (e.g., Shiino 1951; Bamber & Bird 1997; present study). The present species most closely resembles to Tanis tinhauae Bamber & Bird, 1997 , a species described from Hong Kong. Both species have a five-articled antennule, eight-articled antenna, four-articled uropod, similar shapes of labium outer lobes. Nevertheless, T. nuwalianensis can be distinguished from T. tinhauae by two distomedial hooks on distal margin of maxilliped endite, fewer carpal spines on pereopod 2–6, fewer leaf-like setae on the superior margin of pereopod 6, and fewer inner setae of the pleopod basis ( Bamber & Bird 1997: 107, 109, Figs 2 B, 3B–G; present study: Fig 6 A–I, Table 2).

Figures

FIGURE 2. Aparatanais lenoprimorum sp. nov. Holotype (NMNS 7214 - 1): A left maxilliped endite; B right maxilliped palp; C left maxilliped palp; D closed-up of right maxilliped palp article 2 medial spine; E right cheliped; F right Pereopod 1; G right Pereopod 2. Scale: A – G, 0.1 mm.

FIGURE 4. Tanais nuwalianensis sp. nov. Holotype (NMNS 7214 - 5) female: A body dorsal view; B allotype male (NMNS 7214 - 6), dorsal view; C female right antennule; D female right antenna; E female labrum; F female labium; G female left mandible; H distal area closed-up of female left mandible incisor and lacinia mobilis; I distal area closed-up of female right mandible; J female right mandible incisor and lacinia mobilis. Scale: A – B, 1 mm; C – J, 0.1 mm. C – J from holotype female.

FIGURE 5. Tanais nuwalianensis sp. nov. Holotype (NMNS 7214 - 5): A right maxillule; B epignath; C maxilliped; D maxilliped endite; E right cheliped; F right Pereopod 1; G right Pereopod 2. Scale: A – G, 0.1 mm.

FIGURE 6. Tanais nuwalianensis sp. nov. Holotype (NMNS 7214 - 5): A right Pereopod 3; B right Pereopod 4; C medial view of right Pereopod 4; D right Pereopod 5; E ventral closed-up view of right Pereopod 5 carpus; F right Pereopod 6; G medial closed-up view of right Pereopod 6 carpus and merus; H right Pereopod 6 propodus distal row of setae; I right pleopod- 3; J right uropod Scale: A – H, 0.1 mm.