Aparatanais lenoprimorum, 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 : 52-57

Aparatanais lenoprimorum sp. nov.

( Figs 1–3 , Table 1)

Material examined. Holotype ( NMNS 7214-1), non-ovigerous female, 3.85 mm, Shitiping (23°28’N, 121°30’E), eastern Taiwan, intertidal, washing from green alga Halimeda sp., collected by You-Wei Tzeng, March 25, 2011; paratypes: one non-ovigerous female ( NMNS 7214-2), 2.54 mm, Jihuei (23°06’54.9”N, 121°24’16.3”E), eastern Taiwan, intertidal, washing from polychaetous worm tube of Eunice sp., collected by You-Wei Tzeng, August 8, 2010; one specimen one manca-III ( NMNS 7214-3), 1.39 mm, Shitiping (23°28’57.4”N, 121°30’46.9”E), eastern Taiwan, intertidal, washing from brown alga Sargassum sp., collected by You-Wei Tzeng, August 8, 2010; one non-ovigerous female ( NMNS 7214-4), 3.08 mm, Jihuei (23°06’54.9”N, 121°24’16.3”E), eastern Taiwan, intertidal, October 17, 2009.

Diagnosis. Female: Cephalothorax with carapace divided into plates. Pleonites 1–4 epimera with one plumose seta. Left mandible lacinia mobilis without crenulations, right mandible incisor superior margin smooth. Maxilliped palp article 2 modified spine with four denticles. Cheliped palms without various spines, fixed finger with three setae on incisive margin.

Description. Holotype ( Fig 1 A): body long cylindrical, with length/width ratio about 6.6. Cephalothorax about 1/5 of body length, as long as broad, with two well separated eye-lobes, carapace divided into four plates. Pereon with all pereonites shorter than broad, pereonites 2 and 4 longest, interpereonites extended; pleon about 1/5 of body length, pleonites 1–4 each with one plumose seta laterally; pleotelson semicircular.

Antennule ( Fig 1 C) about 3/5 of cephalothorax length, four-articled plus one terminal cap-like segment; article 1 40% of total length of antennule, with four lateral setae and one distal seta; article 2 short, about 40% length of article 1, distal margin with two simple setae and three short bipinnate setae; article 3 shorter than article 2, with one distal seta; article 4 as long as article 2 and article 3 combined; cap-like segment with five setae. Antenna ( Fig 1 D) six-articled (i.e. five articles plus one terminal cap-like segment); article 2 three times longer than article 3, with one superodistal seta, superior margin setulated; article 3 superior spine acute; article 4 1.3 times as long as article 3; article 5 as long as article 3, with two distal setae; cap-like segment with five long setae.

Labrum ( Fig 1 E) hood-shaped covered with fine setules. Labium ( Fig 1 F) bi-lobed, outer lobes much reduced, superior margin of these and inner lobes finely setules. Mandibles ( Fig 1 G–H) pars molaris well developed; lacinia mobilis superior margin not crenulated; right incisor pointed, superior margin smooth. Maxillule endites ( Fig 1 I) with six long spines and one short spine distally, fine setules on outer margin; palps ( Fig 1 J) with two distal long setae. Maxilliped endites ( Fig 2 A) distal margin with three longitudinal rows of setules, two rounded tubercles, and one medial long seta, distolateral margin with about ten denticles; palp ( Fig 2 B–D) article 1 without seta, article 2 with two simple setae and one large spine with four serrations, article 3 with three long bipinnate setae and one short bipinnate seta; article 4 with three long bipinnate setae, one long simple seta, one short simple seta, and several proximal setules.

Cheliped ( Fig 2 E) attached to cephalothorax via sclerite, with triangular insertion to basis, basis typical, with one distodorsal seta; merus with one inferior seta; carpus stout, 1.2 times ltb (longer than broad), with two superior setae; propodus including fixed finger 0.8 times as long as carpus, kukri-shaped spine absent, inferior margin with two setae, without medial spine, fixed finger incisive margin with large blunt distal process and three setae; dactylus stout, with one medial peg-like spine, unguis heavily calcified.

Pereopod 1 ( Fig 2 F) basis long and slender, 5.7 times ltb, naked; ischium very short, 0.75 times ltb, with one inferodistal seta; merus elongated, 3.0 times ltb, naked; carpus 2.5 times ltb, with three distal setae; propodus 1.5 times as long as carpus, 3.6 times ltb, with three distal setae and one small superodistal denticle; dactylus and unguis combined 0.8 times as long as propodus. Pereopod 2 ( Fig 2 G) shorter than pereopod 1; coxa with one simple seta; basis stout, 2.2 times ltb; ischium very short and unremarkable, with one inferior seta; merus with one inferodistal spine; carpus as long as merus, with one large superodistal spine and two smaller inferodistal spines; propodus shorter than merus and carpus combined, with three distal setae and one small superodistal denticle. Pereopod 3 ( Fig 3 A) similar to pereopod 2 except basis more slender, 4.0 times ltb. Pereopod 4 ( Fig 3 B) the shortest, 90% length of pereopod 5 and 85% length of pereopod 6; basis stout, 2.0 times ltb, with one inferior seta and two inferodistal setae; merus with two inferodistal non-serrated spines, inferior margin with one row of fine setules; carpus with one large superodistal spine and three smaller inferodistal spines, inferior margin with two rows of setules; propodus with one long superodistal seta, one dorsal plumose seta and two inferodistal spines, inferior margin with one row of fine setules; dactylus and unguis fused to claw. Pereopod 5 ( Fig 3 C) similar to pereopod 4 but basis inferior margin with two bipinnate setae, one simple seta and two inferodistal setae. Pereopod 6 ( Fig 3 D) similar to pereopod 4 but basis with one superior seta, one inferior seta and one inferodistal seta, propodus with three long superodistal strong pinnate setae.

Pleopod ( Fig 3 E) basis naked; exopod with 22 plumose setae on outer margin; endopod inner margin setulate with one plumose seta, outer margin with 17 plumose setae.

Uropod ( Fig 3 F) short; peduncle as long as broad; exopod one-segmented, just over 1/2 of endopod length, with two distal setae; endopod two-segmented, as long as peduncle, segment-1 with one distal seta, segment-2 with six distal setae and two short bipinnate setae on lateral margin.

Etymology. The name is derived from the Latin “ lenis ” (smooth) and “ primorum ” (incisor), implying the presence of smooth superior margin on right incisor of the species.

Type locality. Shitiping, eastern Taiwan.

Distribution. It is only known from Shitiping and Jihuei, eastern Taiwan.

Remarks. Of six described species, the present species most closely resembles Aparatanais denticulatus ( Gutu & Ramos, 1995) , recorded from Columbia, South America. Both species have the carapace divided into four plates and the lack of kukri-shaped sinuate spine on palm of chelipeds ( Table 1). Yet, they are distinguishable by several morphological characters. First, Aparatanais lenoprimorum lacks any serration on the left mandible lacinia mobilis, in contrast to 5 serrations on that of A. denticulatus . Second, the former species has non-crenulated right mandible incisor and four plumose setae on pleon epimerons, whereas the latter species has crenulations on right mandible incisor and four simple setae on pleon epimerons. Finally, the former species has serrated spines on the second article of the maxilliped palp, but the latter species possesses denticulated spines on the same mouth part ( Gutu & Ramos, 1995: Figs 6 A, E–F, 7A–C; present study: Figs 1 A–B, G–H, 2B–E, Table 1).

Bird and Bamber (2013) commented that the primary morphological character for the genus Aparatanais is the presence of the heavy serrate spine on the maxilliped palp article 2, and other supporting characters (i.e., small maxilliped endite tubercles, a kukri-shaped cheliped palm spine, a long pereopod 1 merus, a relatively narrow pereopod 3 propodus, and short uropods) are not necessarily present simultaneously in all the taxa of the genus. On the same token, the lack of crenulations on right mandible incisor of the present species may be considered as an exemption from the generic diagnosis.

A. lenoprimorum A. denticulatus A. intermedius A. malignus A. spinanotandus A. timutimu A. vicentetis body robust, 2.54 mm; robust, 4.2 mm robust, 2.16 mm robust, 3.1 mm robust, 3 mm fairly slender, robust, 3.5 mm

fairly slender, 3.85 mm 2.3–5.8 mm

carapace plated plated not plated not plated plated not plated not plated mandible not serrated 5 serrations 5 serrations 4 serrations 5 serrations? 2 serrations lacinia mobilis

mandible pointed, not crenulate pointed, crenulate? obtuse, crenulate, pointed, crenulate pointed, crenulate pointed, crenulate incisor bifid

maxillule 7 7? 7 9 atleast7 7 apical spines

kukri-shaped absent absent absent present present present present cheliped palm

spine

pleon 4 plumose 4 simple absent 4 plumose absent 4 plumose 4 plumose epimeral setae

Figures

FIGURE 1. Aparatanais lenoprimorum sp. nov. Holotype female (NMNS 7214 - 1): A body dorsal view; B paratype female (NMNS 7214 - 2), dorsal view; C left antennule; D left antenna; E labrum; F labium; G left mandible; H right mandible; I left maxillule endite; J left maxillule palp. Dashed lines of A – B indicate less calcified carapace areas. Scale: A – B, 1 mm; C – J, 0.1 mm. C – J from holotype female.

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 3. Aparatanais lenoprimorum sp. nov. Holotype (NMNS 7214 - 1): A – D right pereopods from 3 – 6, respectively; E right pleopod- 1; F right uropod. Scale: A – F, 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.