Nuberis areolaticola, Bamber, Roger N. & Marshall, David J., 2015

Bamber, Roger N. & Marshall, David J., 2015, Tanaidaceans from Brunei, V. The Leptocheliidae (Crustacea: Peracarida: Tanaidacea), with four new species, Zootaxa 3948 (3), pp. 342-360 : 348-349

Nuberis areolaticola sp. nov.

Figs 4–5

Material: Holotype. Brooding female, ( NHMUK 2015. 2877), sample DAR, 05°54′28.5"N 114°38′23.3"E, 20 m depth, sand, March, 2009.

Paratypes. Two brooding ♀♀, ( NHMUK 2015. 2878 - 2879), one ♀ (dissected, not retained), sample B13, 04°51′06"N 114°35′26"E, 20 m depth, sand; three ♀♀ (one brooding), ( NHMUK 2015. 2880 - 2882), sample DA1; one ♀, one juvenile, ( NHMUK 2015. 2883–2884), sample DA2; both 05°54′28.5"N 114°38′23.3"E, 20 m depth, sand, March, 2009.

Description of brooding female. Body ( Fig. 4 A) slender, nine times as long as wide, holotype 2 mm long. Cephalothorax subrectangular, 1.5 times as long as wide, shorter than pereonites 1 and 2 together, with slight rostrum, eyelobes rounded, eyes present and brown (pigment absent in some preserved material). Pereonites with paired (pereonites 1–5) or single (pereonite 6) lateral setae; pereonite 1 half as long as cephalothorax and 1.3 times as wide as long; pereonites 2 to 4 subequal in length, 1.7 times as long as pereonite 1 and about 1.3 times as long as wide; pereonite 5 as long as wide, 1.4 times as long as pereonite 1; pereonite 6 shortest, half as long as pereonite 5 and 1.6 times as wide as long. Pleon as long as pereonite 5; each pleonite about six times as wide as long, naked. Pleotelson subrectangular, as long as last two pleonites together, twice as wide as long, with four fine distal setae.

Antennule ( Fig. 4 B) of three articles, flagellum fused to third article; proximal article 3.4 times as long as wide, 1.8 times as long as distal two articles together, with proximal and distal single penicillate and single simple setae on outer margin; second article about twice as long as wide, one-quarter as long as first article, three simple distal setae all shorter than article; third article 1.3 times as long as second, with five distal setae and one aesthetasc.

Antenna ( Fig. 4 C) proximal article compact, naked; second article as long as wide, distally with slender ventral and dorsal spines; third article shorter than second, with dorsodistal slender spine; fourth article longest, 4.5 times as long as wide and three times as long as third, with short mid-length seta and three distal simple setae; fifth article half as long as fourth, with two distal setae; flagellum minute, with five distal setae.

Labrum not recovered. Left mandible ( Fig. 4 D) with crenulate lacinia mobilis bearing inner-distal extension, coarse distal crenulation on pars incisiva, pars molaris blunt without rugosity; right mandible ( Fig. 4 E) similar but without lacinia mobilis, pars incisiva distally bifid and with twelve fine marginal crenulations. Labium ( Fig. 4 F) wide, bilobed, distally finely setose. Maxillule ( Fig. 4 G) endite with eight distal spines and sparse marginal setae, palp with two distal setae. Maxilliped ( Fig. 4 H) palp first article naked, second article with three inner setae, no outer seta; third article with five inner marginal setae in distal half, proximal inner margin finely setulose; fourth article with distal row of four simple setae and one mesial and two outer subdistal setae; basis with one distal seta; endites distally with fine outer setules, outer simple seta, two pointed spines and one rounded inner blunt spine. Epignath ( Fig. 4 I) slender, distally with marginal setules and one slender seta.

Cheliped ( Fig. 5 A) with rounded, comparatively slender basis 2.8 times as long as wide, naked; merus triangular with one ventral seta; carpus 2.5 times as long as wide, with three ventral setae and two dorsal marginal setae; propodus 1.4 times as long as wide, with inner distal “comb” of one seta with adjacent microtrichia ( Fig. 5 A ′), outer seta at base of dactylus; fixed finger with two ventral setae and three setae adjacent to slightly crenulate cutting edge; dactylus with inner proximal seta.

Pereopod 1 ( Fig. 5 B) longer than other pereopods, coxa with seta; basis sinuous, four times as long as wide, with single dorsoproximal simple seta; ischium compact with one ventral seta; merus one-third as long as basis, naked; carpus 1.6 times as long as merus, with dorsal seta longer than width of carpus; propodus 1.9 times as long as carpus, with two setae on subdistal dorsal mound and one subdistal ventral seta; dactylus slender, extending into shorter slender unguis 0.6 times as long as dactylus, the two together 1.2 times as long as propodus. Pereopod 2 ( Fig. 5 C) more compact than pereopod 1; basis three times as long as wide, with dorsoproximal simple seta; ischium with one ventral seta; merus 0.4 times as long as basis, naked; carpus 1.2 times as long as merus, with single fine ventrodistal seta; propodus 1.3 times as long as carpus, with two distal setae; dactylus and short unguis curved, together 0.6 times as long as propodus. Pereopod 3 ( Fig. 5 D) as pereopod 2.

Pereopod 4 ( Fig. 5 E) basis stout, 2.3 times as long as wide, naked; ischium with two ventrodistal setae; merus 0.3 times as long as basis, with paired ventrodistal spines; carpus 1.3 times as long as merus, with outer, ventral and inner distal spines ( Fig. 5 E ′); propodus as long as carpus, with two ventrodistal spines, three dorsodistal setae two of which being as long as dactylus; dactylus and unguis apparently fused, half as long as propodus. Pereopod 5 ( Fig. 5 F) as pereopod 4, but carpus shorter than merus, propodus nearly twice as long as carpus. Pereopod 6 ( Fig. 5 G) as pereopod 5.

Pleopods ( Fig. 5 H) all alike, all setae plumose; basis naked, endopod without inner seta but with five distal setae; exopod with seven distal and one proximal setae.

Uropod ( Fig. 5 I) biramous, basis naked; exopod of two segments, 1.3 times as long as proximal endopod segment, setose as figured; endopod of four segments, distal segments slender.

Male unknown.

Etymology. From the Latin— areolata-icola —a dweller in small spaces, i.e. interstitial (adjectival).

Remarks. Nuberis areolaticola sp. nov. was taken sparsely in clean sands at 20 m depth. Aspects of its morphology attributed to its interstitial mode of life are similar to those discussed above under Brunarus colekanus . It is most-easily distinguished from that species at the whole-animal level by its proportionately longer first pereonite.

Figures

FIGURE 4. Nuberis areolaticola gen. et sp. nov., A, holotype female, dorsal; B, antennule; C, antenna; D, left mandible; E, right mandible; F, labium; G, maxillule; H, maxilliped, with H ′, detail of endite; I, epignath. Scale line = 0.5 mm for A, 0.1 mm for B to I.

FIGURE 5. Nuberis areolaticola gen. et sp. nov., A, right cheliped with A ′, detail of dactylus of left cheliped; B, pereopod 1; C, pereopod 2; D, pereopod 3; E, pereopod 4 with E ′, detail of distal spination of carpus; F, pereopod 5; G, pereopod 6; H, pleopod (most setae shown only by their bases, plumosity of all seta omitted); 1, right uropod. Scale line = 0.1 mm.