Pagurapseudes queirosi, Bamber, 2009

Bamber, Roger N., 2009, Two new species of shell-inhabiting tanaidaceans (Crustacea, Peracarida, Tanaidacea, Pagurapseudidae, Pagurapseudinae) from the shallow sublittoral off Vanuatu, Zoosystema 31 (3), pp. 407-418 : 408-412

Pagurapseudes queirosi n. sp.

( Figs 1 ; 2 )

TYPE MATERIAL. — Holotype: Vanuatu. SANTO 2006 , stn DB86, Malo Island off Avunaro Point, 15°38.5’S, 167°15.1’E, 13 m depth, 4.X.2006, 1 ♀ (MNHN-Ta 955).

Paratypes: same data as holotype, 14 brooding ♀♀, 14 other ♀♀, 5 ♂♂, 13 juveniles, 24 other specimens (MNHN-Ta 956) ; 2 brooding ♀♀, 2 other ♀♀, 2 ♂♂, 2 juveniles, 2 other specimens ( BMNH.2007.952-961) ; 2 ♀♀, dissected (coll. R. Bamber). — Stn FB 52, Malo Island (Kili Kili), 15°28.2’S, 167°15.0’E, 7 m depth, 5.X.2006, 5♂♂, 4 ♀♀, 25 other specimens (MNHN-Ta 957). — Stn DB 63, Aégé Island, 15°26.5’S, 167°15.50’E, 21 m depth, 25.IX.2006, 1 ♀ (dissected; not retained) .

TYPE LOCALITY. — Vanuatu, Santo, Malo Island off Avunaro Point, 15°38.5’S, 167°15.1’E, 13 m depth.

ETYMOLOGY. — Named after Pedro Fernandes de Queirós, the Portuguese explorer who was reputedly the first European to sight the Vanuatu Islands, in 1606.

DESCRIPTION OF FEMALE

Body ( Fig. 1A ) typical of a pagurapseudid, pleon skewed to right and curved under pereon; small,

holotype about 3.5 mm long. Cephalothorax ( Fig. 1B ) slightly narrower anteriorly, 0.9 times as long as wide, with convex anterior margin, rostrum represented by medial group of five teeth; single seta behind ocular lobe, one postero-dorsal pair of simple setae. Eyelobes distinguished with anterior pointed apophysis, eyes present as group of black-pigmented ocelli.Epistome absent.Six free pereonites; pereonite 1 shortest, 0.9 times as long as pereonite 2; pereonite 3 longest, twice as long as pereonite 1; pereonites 4 to 6 subequal, 0.85 times as long as pereonite 3. Pleon of five free subequal pleonites, each pleonite about half as long as pereonite 6. Pleonite 1 only bearing pleopods, remaining pleonites with pair of small ventral tubercles bearing single seta. Pleotelson ( Fig. 1E ) semicircular, about as long as last two pleonites together, 1.3 times as long as wide, with plumose lateral, and simple dorsal and posterior setae as figured.

Cephalothorax and pereonites with pale brown colouration dorsally, darkest along anterior margin, with central pale band. Same colouration as patches on proximal antennule peduncle article.

Antennule ( Fig. 1C ) proximal peduncle article 3.7 times as long as wide, with conspicuous inner spine-like apophyses accompanied by simple setae, no distal apophysis; second peduncle article 0.4 times as long as first; third article 0.15 times as long as second, fourth article one-third length of third. Main flagellum of three segments, with single aesthetascs on each segment; accessory flagellum of one segment, distally not quite reaching distal edge of second segment of main flagellum.

Antenna ( Fig.1D ) with two basal articles fused into wide proximal peduncle article bearing two setose inner apophyses and paired outer-distal plumose setae; second article as long as wide; third peduncle article twice as long as second, fourth three-times as long as second. Flagellum of two segments, distal segment with four distal setae.

Labrum ( Fig. 1J ) bilobed, rounded, sparsely setose. Right mandible ( Fig. 1F ) with tricuspid pars incisiva, setiferous lobe with four variously crenulate setae, pars molaris round, blunt, simple; palp of three articles, proximal article with long, plumose inner seta, second article longest, 2.3 times as long as proximal article, with eight inner setae in two rows; third article three-quarters as long as second, with eight progressively longer setae in distal half, distal seta longer than article. Left mandible as right but with narrow, bicuspid lacinia mobilis ( Fig. 1G ). Labium ( Fig. 1I ) typically marginally setose, palp with two distal setae.Maxillule ( Fig.1H ) inner endite with four simple distal setae, outer endite with nine distal spines, outer margins sparsely setose; palp of two articles with indistinct articulation, distally with four simple setae. Maxilla damaged in preparation, with rostral row of about 20 simple setae, fixed endite with trifurcate, simple and bifurcate setal groups. Maxilliped ( Fig. 1K ) basis with four distal plumose setae; proximal palp article with simple outer margin with two plumose setae, inner margin naked; second article with one long plumose seta on outer margin, three shorter simple spines and five plumose setae along inner margin; third article with one distal and three inner marginal simple setae; distal article with 12 simple inner-marginal and distal setae in two rows, paired outer subdistal simple setae; endite (not figured) with finely setose outer margin, simple distal spines, three couplinghooks. Epignath ( Fig. 1L ) large, inner lobes conspicuous, distal spine proximally setose and with short marginal spinules in distal half.

Chelipeds ( Fig. 2A ) showing no conspicuous dimorphism. Compact basis 1.25 times as long as wide, with subdistal, ventral plumose seta and ventral marginal spines; exopodite absent. Merus subtriangular, inner and distal plumose setae and ventral simple seta. Carpus elongate, 1.6 times as long as wide, widening distally, with numerous fine setae but no spines or apophyses. Propodus robust, 1.5 times as long as wide, setose as figured; fixed finger with saw-like row of small teeth distally on cutting edge; moveable finger stout, curved.

Pereopod 1 ( Fig. 2B ) longest, with stout basis twice as long as wide, dorsal margin bearing nine plumose setae interspersed amongst triangular tooth-like apophyses, ventral margin with six ventral and distal plumose setae; exopodite present ( Fig. 2C ), large, distal article with 13 plumose setae. Ischium onequarter as long as basis, with naked dorsal margin, simple ventral setae and single ventrodistal plumose seta. Merus 0.9 times as long as basis, dorsally with stout plumose seta on small marginal tubercle in proximal half, ventral margin with plumose setae and spines, microtrichia mainly in distal half.Carpus shorter than merus, with ventral and distal plumose setae and ventrodistal spine. Propodus 1.5 times as long as carpus, with four ventral spines each with crenulate anterior face.Dactylus curved, 0.75 times as long as propodus, with fine ventral setae, unguis slender, sharp, 0.6 times as long as dactylus.

Pereopods 2 to 6 similar to each other, progressively shorter, each about one-half to one-third as long as pereopod 1. Pereopod 2 ( Fig. 2D ) basis stout, 1.4 times as long as wide, with simple ventrodistal seta; ischium with paired ventrodistal setae. Merus, carpus and propodus bearing “sucker-like” spines, generally in two ventral rows, and plumose setae as figured. Merus as long as carpus; propodus 0.75 times as long as carpus; dactylus and unguis appearing to be fused into hook-like claw, with minute inner seta. Pereopod 3 ( Fig. 2E ) with more setae on basis, dorsodistal plumose seta on merus. Pereopod 4 ( Fig. 2F ) shortest, basis 1.6 times as long as wide, fewer “sucker-like” spines on merus. Pereopod 5 as pereopod 4. Pereopod 6 ( Fig. 2G ) basis with paired, long plumose dorsal setae; dactylus and unguis not hook-like, articulation evident.

Pleopods ( Fig. 2H ) only present on pleonite 1, biramous, reduced; basis with single dorsal and ventral plumose setae; exopod with outer proximal and three distal plumose setae, endopod with four distal plumose setae.

Uropod ( Fig. 1E ) biramous, basis with three distal setae; endopod longer than basis, of three segments increasing in length, second segment distally naked, third segment with three stout distal setae and one penicillate seta; exopod of one segment, subequal in length to proximal endopod segment, with two distal setae.

Male closely similar to female, but antennule with more aesthetascs on main flagellum.

REMARKS

Of the five described species of Pagurapseudes with three segments in the main flagellum and only one in the accessory flagellum of the antennule, only three have a 3-segmented uropod endopod. Pagurapseudes dentatus (Brown, 1956) , from the intertidal of South Africa, although generally poorly described, has five pairs of pleopods, the rami of which are distinctly unequal, and, unlike the case in P. queirosi n. sp., the merus, carpus, propodus and dactylus of pereopod 1 are subequal in length. Pagurapseudes setulosa Kazmi & Siddiqui, 2001 , from Pakistan (depth not given) has four pairs of pleopods, which are without basal setae, numerous “setules” along the lateral margins of the pleotelson, and a distinctly more slender cheliped propodus. Pagurapseudes razvani Guţu, 1997 , recorded from Indonesia at 5 m depth is more similar to the present species, but is distinguished in having three pairs of pleopods, a three-articled flagellum to the antenna, as well as lateral rows of plumose setae on the cephalon and distinct bifurcate spines adjacent to the dactylus of pereopods 2 and 3.

Using the key of Guţu (1997) to the nine species known at that time, the present species would key out to the type species, P. spinipes Whitelegge, 1901 ; however, that species has four segments in the main flagellum of the antennule (note that, in his text, Whitelegge [1901] included the distal peduncle article in both flagella), and the basis of pereopod 1 has no plumose setae, Whitelegge (1901) describing and figuring only “a few small denticles on the anterior border”.

The only species described since the work of Guţu (1997) are P. setulosa (see above), and P. inquilinus Bamber, 2007 , from 440-450 m depth off New Caledonia, but that species is readily distinguished from P. queirosi n. sp. in having seven segments to the antennular main-flagellum, inter alia. The large dorsal plumose seta, arising from a distinct tubercle, on the merus of pereopod 1 seems to be unique to P. queirosi n. sp.

Figures

FIG. 1. — Pagurapseudes queirosi n. sp.:A, holotype ♀, lateral; B, cephalothorax,dorsal;C, left antennule;D, left antenna;E, pleotelson and uropods; F, right mandible; G, distal detail of left mandible; H, maxillule; I, labial palp; J, labrum; K, maxilliped; L, epignath. Scale bar: A, 1 mm; B, 0.5 mm; C-L, 0.2 mm.

FIG. 2. — Pagurapseudes queirosi n. sp.: A, left cheliped; B, pereopod 1 (exopodite indicated by dotted lines); C, exopodite of pereopod 1; D, pereopod 2; E, pereopod 3; F, pereopod 4; G, pereopod 6; H, pleopod. Scale bar: A, B, H, 0.2 mm; C-G, 0.1 mm.