Anisopechys crinitus, Bird, Graham, 2004

Bird, Graham, 2004, Tanaidacea (Crustacea) of the Northeast Atlantic: non­filiform species of Anarthruridae Lang from the Atlantic Margin, Zootaxa 471, pp. 1-44 : 34-37

Anisopechys crinitus sp. nov. ( Figs. 15–16 )

Anarthrura sp.2: Holdich & Bird, 1989: tables III, IV and appendices as taxon ‘26’. Anarthrura sp.AM#2: Bird, 2001: 25 –26

Material examined. Holotype ( NHM 1988:540) SMBA Stn SBC64, one neuter. Paratypes AFEN 1998 Stn 54587#1, one manca­II ( NMSZ:218.2160); SMBA Stn SBC64, three neuters ( NHM 1988:540); SBC67 one manca­II ( NHM 1988:541); SBC168, one manca­II, one neuter ( NHM 1988:542); SBC222, one prep. male ( NHM 1988:543); SBC279, one manca­II ( NHM 1988:540); Thalassa 1973 Stn Z426, one neuter.

Also seen SBC 214, two specimens ( NHM 1989:911:4); SBC222, 17 individuals ( NHM 1988:543); SBC237, one specimen ( NHM 1989:911:4); ‘Sarsia’ Stn 56, one specimen ( NHM 1988:545).

Description. Non­ovigerous female/neuter. Body ( Fig. 15 A) fairly slender, about seven times longer than broad, length 1.80–2.46 mm. Cephalothorax 15% of body length, just longer than broad. Pereonite­1 narrower posteriorly, others subrectangular with round corners, pereonites 1–6 0.55, 0.67, 0.75, 0.83, 0.88, and 0.78 times as long as broad respectively. Pleon ( Fig. 15 B) 17% of body length, slightly narrower than pereon, epimera convex with one or two (pleonite­6) setae. Pleotelson ( Fig. 15 C) about as long as preceding two pleonites, shorter than broad, with conical apex, with six setae. Cuticle weakly calcified.

Antennule ( Fig. 15 D) 0.8 times as long as cephalothorax, article­1 about half of total length, article­4 with aesthetasc and six setae, other setation as figured. Antenna ( Fig. 15 E) 80% length of antennule, articles 2 and 3 short, with dorsal seta, article­4 with weak ‘pseudoarticulation’, with several distal setae, article­5 half length of article­4, article­6 small with five terminal setae.

Labium not recovered. Labrum ( Figs. 15 F–G) as in generic diagnosis. Mandibles ( Fig. 15 H) weak, with broad incisor process. Maxillule endite ( Fig. 15 J) with seven (?) unequal spiniform setae and at least one ordinary seta. Maxilliped ( Fig. 16 A) basis with short seta at articulation with palp, endite conical with distal setal fringe; palp article­1 short, with lateral seta, article­2 with long seta and two strong bifid setae, article­3 largest with three large plumose setae and small anterior seta, article­4 rectangular, with four plumose setae.

Cheliped ( Fig. 15 K) pseudocoxa just longer than basis and merus combined; basis subconical, 0.8 times as long as broad; merus subtriangular, with ventral seta; carpus about twice as long as greatest width, with two setae on dorsal margin and one on ventral margin near merus; propodus of complex shape, forming near right­angle from main axis, with curved ridge on lateral margin, fixed finger conical with triangular apex, a small subventral seta and three setae near incisive margin, one seta near articulation with dactylus, with three triangular teeth on incisive margin; anterior margin of propodus ( Fig. 16 B) with dorsal, setae­fringed ridge and comb of three strong setae; dactylus deep and strongly arched, with large anterior seta.

Pereopod­1 ( Fig. 16 C) basis curved, about four or five times longer than broad; ischium with small seta; merus with two ventral setae; carpus subrectangular, with four distal setae; propodus with groups of small setae on dorsal margin, and distal seta; dactylus and unguis together as long as propodus, dactylus with accessory seta. Pereopods 2 ( Fig. 16 D) and 3 similar to pereopod­1 but merus and carpus proportionately shorter.

Pereopods 4–6 ( Figs. 16 E–F, pereopod 5 not figured) similar; basis tumid, three times longer than broad; ischium with one seta; merus with two blunt spiniform setae bearing spinules; carpus with three unequal blunt spiniform setae and dorsal seta; propodus with two ventrodistal spiniform setae (three on pereopod­6) and a long spatulate distal seta; dactylus and unguis short.

Pleopod ( Fig. 16 G) rami of extended oval shape, endopod smaller than exopod, with seven distal setae; exopod with one proximal seta and distal fringe of eight or nine setae. Uropod ( Fig. 16 H) longer than pleotelson, exopod about three times as long as broad and one third as long as endopod, with three setae; endopod slender, one­articled, with distal sensory and four terminal setae.

Manca­II. Body ( Fig. 16 J) generally similar to neuter but of stouter shape, five times longer than broad, pereonite­6 only as long as a pleonite, pleon of same breadth as pereon, pereopods­6 and pleopods absent. Length 1.02–1.34 mm.

Preparatory male. Similar to neuter but antennule thicker. Length 2.14 mm.

Type locality. Hebrides Slope, 56o 38’N 9o 29’W, 1400 m.

Etymology. Latin crinitus , ‘hairy’ alluding to the setose fringe on the maxilliped endites and cheliped propodus.

Remarks. A bathyal inhabitant from south of the Wyville Thomson Ridge in the Margerita Bight and on the Hebrides, Malin, Celtic and South Biscay Slopes. Of the ten records from 641–1498 m only two of these detail sediment type: ‘sandy mud’.

Figures

FIGURE 15. Anisopechys crinitus. Non­ovigerous female A, dorsal; B, pleon, lateral view; C, pleotelson; D, antennule; E, antenna; F – G, labrum, lateral and dorsal views; H, mandible; J, maxillule endite, distal; K, cheliped. Scale bar 1 mm (A).

FIGURE 16. Anisopechys crinitus. Non­ovigerous female A, maxilliped; B, left chela, anterior view; C, pereopod­ 1; D, pereopod­ 2; E, pereopod­ 4; F, pereopod­ 6; G, pleopod; H, uropod; J, manca­II. Scale bar 1 mm (J).