Brunarus colekanus, 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 : 343-348

Brunarus colekanus sp. nov.

Figs 1–3 .

Material: Holotype. Female ( NHMUK 2015. 2866), Station S5, 04°42′26.5"N 114°26′02"E, 11.5 m depth, sand.

Paratypes. Six ♀♀, four juveniles, ( NHMUK 2015. 2867 - 2876), one further ♀, dissected, Station S18, 04°41′30"N 114°27′13.5"E, 7.5 m depth, sand. Coll. March 2009.

Description of female. Holotype body ( Fig. 1 A) 3.1 mm long, 8.5 times as long as wide. Cephalothorax elongate, subrectangular but with margins narrowing towards anterior, 1.5 times as long as wide, longer than pereonites 2 and 3 together, with slight rounded rostrum, rounded eyelobes conspicuous, eyes present and black, one lateral seta at posterior of each eyelobe; slight mid-dorsal groove distinguishing second thoracomere at posterior of cephalon. Pereonites naked; pereonite 1 shortest; pereonites 2, 3 and 6 subequal, twice as long as pereonite 1, and about 1.2 times as wide as long; pereonites 4 and 5 subequal, 3.5 times as long as pereonite 1, and 1.3 times as long as wide. Pleonites each about four times as wide as long, with paired simple epimeral setae. Pleotelson semicircular, one-fifth length of whole pleon, 2.3 times as wide as long, with single mid-lateral, paired laterodistal and four fine distal setae.

Antennule ( Fig. 1 B) of three articles, without distal cap-like segment; proximal article tumid, 2.2 times as long as wide, 1.6 times as long as distal two articles together, with one longer distal outer simple setae, a number of shorter and longer medial and inner simple setae, and median and distal outer tufts of penicillate setae; second article longer than wide and 0.3 times as long as first article, distal setae much shorter than article; third article five times as long as wide and 1.3 times as long as second article, with eight simple distal setae and one aesthetasc.

Antenna ( Fig. 1 C) proximal article robust, naked; second article just longer than first, 1.2 times as long as wide, with fine ventrodistal seta, shorter dorsodistal seta and dorsal margin fringed with setules; third article just longer than wide, 0.6 times as long as second article, with single dorsodistal seta; fourth article longest, three times as long as third article and 4.5 times as long as wide, with simple seta at mid-length and four simple and one penicillate distal setae; fifth article as long as second article and with two distal simple setae; flagellum minute, with six distal setae.

Labrum ( Fig. 1 D) lobate, distally setose. Left mandible ( Fig. 1 E) with lacinia mobilis not crenulate, pars incisiva with three coarse crenulations, pars molaris blunt, with some distal rugosity; right mandible ( Fig. 1 F) similar but without lacinia mobilis, pars incisiva with 12 crenulations, tip bifid. Labium ( Fig. 1 G) wide, bilobate, distally finely setose. Maxillule ( Fig. 1 H) with eight (?) distal spines, distally setose outer and mesial margins; palp distinct, with two distal setae. Maxilla not seen. Maxilliped ( Fig. 1 I) palp first article naked, second article with one outer and four inner setae, distal-most inner seta exceeding distal margin of third palp article; third article with inner row of six setae; fourth article with distal row of three simple setae and one mesial and two outer subdistal setae; basis with two distal setae; each endite ( Fig. 1 I ′) distally with single outer blunt-tipped seta, two pointed spines and one rounded inner blunt spine, outer corner setulose. Epignath (not figured) typical for the subfamily, elongate, slender, setose.

Cheliped ( Fig. 2 A, B) stout; coxal sclerite with two outer setae; basis 2.3 times as long as wide, with mesial dorsodistal slender seta on slender tubercle; merus triangular with seven ventral setae; carpus twice as long as wide, outer margin extended ventrodistally and distally to form cuff around base of propodus, with one distal and one subproximal dorsal marginal setae, and three ventral setae; propodus just longer than wide, outer distal margin extended into apophysis bearing strong seta, inner comb-row of three spines with adjacent microtrichia; fixed finger just shorter than propodus, with two ventral setae and three inner setae, cutting edge not crenulate, terminal spine subdistal; dactylus simple with proximal seta less than half as long as dactylus.

Pereopod 1 ( Fig. 3 A) longer than other pereopods, coxa with long seta; basis curved, 3.3 times as long as wide, with dorsoproximal seta almost as long as basis width; ischium with two setae; merus half as long as basis, with one ventrodistal seta; carpus as long as merus, with four distal setae, longest of which is more than half length of propodus; propodus 1.3 times as long as carpus, with one ventral and three dorsal subdistal setae; dactylus slender, with dorsoproximal seta not reaching tip of dactylus, curved unguis 1.6 times as long as dactylus, the two together 1.2 times as long as propodus.

Pereopod 2 ( Fig. 3 B) more compact than pereopod 1; basis 4.2 times as long as wide, with single simple dorsoproximal seta almost as long as basis width; ischium with two setae; merus about one-third as long as basis, with one ventrodistal seta; carpus just longer than merus, with single dorsodistal and ventrodistal setae; propodus 1.2 times as long as carpus, with three subdistal setae, one of these longer than dactylus plus unguis; dactylus just longer than unguis, both together 0.6 times as long as propodus. Pereopod 3 ( Fig. 3 C) as pereopod 2, but merus with two ventrodistal setae, propodus with one distal seta.

Pereopod 4 ( Fig. 3 D) basis stout, twice as long as wide, with two ventroproximal penicillate setae of different form; ischium compact, with two ventrodistal setae; merus one-third as long as basis, with two ventrodistal tubercle-mounted setae; carpus as long as merus, with one ventrodistal and single outer and inner distal molariform spines and one dorsodistal seta; propodus 1.3 times as long as carpus, with paired ventrodistal spines and three dorsodistal setae, two of which are longer than dactylus plus unguis; dactylus and minute unguis apparently fused into an claw, curved, 0.6 times as long as propodus. Pereopod 5 ( Fig. 3 E) as pereopod 4, but basis with only one penicillate seta, propodus with only two distal setae, dactylus with dorsal seta. Pereopod 6 ( Fig. 3 F) similar to pereopod 4, but basis with no penicillate setae, propodus as long as carpus and with two longer dorsodistal setae and three shorter distal setae.

Pleopods ( Fig. 3 G) all alike, basis naked; all setae on rami plumose; endopod without inner plumose seta; proximal outer seta on each ramus slightly separated from others.

Uropod ( Fig. 3 H) basis naked; exopod of two semi-fused segments, first segment with outer seta, second segment with outer distal seta longer than inner distal seta; endopod of five segments, setose as figured, first and second segments partially fused, together longer than exopod, third segment longer than others.

Male unknown.

Etymology. From the Greek— kolekanos, a long, thin person (adjectival).

Remarks. Brunarus colekanus sp. nov. was taken in clean sands over a depth range from 7.5 to 11.5 m.

Figures

FIGURE 1. Brunarus colekanus gen. et sp. nov., A, holotype female, dorsal; B, antennule; C, antenna; D, labrum; E, left mandible; F, right mandible; G, labium; H, maxillule; I, maxilliped, with I ′, detail of endite. Scale line = 1.0 mm for A, 0.2 mm for B to I.

FIGURE 2. Brunarus colekanus gen. et sp. nov., A, right cheliped; B, distal articles of left cheliped. Scale line = 0.2 mm.

FIGURE 3. Brunarus colekanus gen. et sp. nov., A, pereopod 1; B, pereopod 2; C, pereopod 3; D, pereopod 4 with detail of tubercle-mounted seta on merus and distal spine on coxa; E, pereopod 5; F, pereopod 6; G, pleopod (most setae shown only by their bases, plumosity of all seta omitted); H, left uropod. Scale line = 0.2 mm.