Apseudes batillus, Bamber, 2007

Bamber, Roger N., 2007, New apseudomorph tanaidaceans (Crustacea, Peracarida, Tanaidacea) from the bathyal slope off New Caledonia, Zoosystema 29 (1), pp. 51-81 : 52-58

Apseudes batillus n. sp.

( Figs 1-3 )

TYPE MATERIAL. — Holotype: New Caledonia, S to SW of Île des Pins , CALSUB, stn PL 20 , Cyana dive 1035/41, 22°52.7’S, 167°23’E, 616- 555 m depth, 10.III.1989, coll. A. Guille, ♂ (MNHN-Ta918) . Paratypes:same data as holotype, 1 ♂ (MNHN-Ta919). — New Caledonia, BIOCAL, stn DW 44, 22°47.35’S, 167°14.50’E- 23°47.34’S, 167°14.80’E, 440-450 m depth, 30.VIII.1985, 2 ♀♀ (1 dissected) (MNHN- Ta920) ; 1 subadult ♀ (NHM.2005.2713). — Stn DW 77, 22°15.32’S, 167°15.40’E- 22°15.65’S, 167°15.49’E, 440 m depth, 5.IX.1985, 1 ♂ (NHM.222005.2714).

TYPE LOCALITY. — Off Île des Pins, New Caledonia, 22°52.7’S, 167°23’E.

ETYMOLOGY. — From the Latin “ batillus ”, a shovel, alluding to the shape of the rostrum.

DESCRIPTION

Female

Body morphology as male ( Fig. 1A ), dorsoventrally flattened, holotype 7.9 mm long (tip of rostrum to posterior of pleotelson), 5.3 times as long as wide, tapering towards posterior. Cephalothorax subrectangular, 1.14 times as long as wide, with pronounced, dorsally concave (“shovel-like”), pointed rostrum with fi nely serrated lateral margins, tip pointing down below eye-lobes ( Fig. 1B ); eyelobes with anterior spinous apophysis, sparse ocelli present, unpigmented in preserved material. Six free pereonites; pereonites 1 and 6 shortest, subequal, about 1/3 as long as cephalothorax, pereonites 2 to 5 each longer than previous pereonite, pereonite 5 about 1.7 times as long as pereonite 1 (all pereonites respectively 3.1, 2.0, 1.8, 1.6, 1.2 and 1.9 times as wide as long); pereonites 1 and 2 laterally smoothly convex, pereonites 3 to 6 with anterolateral hooklike apophysis creating a midlateral indentation, posteriorly smoothly convex. Pleon 3.7 times as long as pereonite 6, of five free subequal pleonites bearing pleopods, each extended laterally into a spinous apophysis bearing setae; pleonites 5.5 times as wide as long, with four (pleonite 1) or two anterodorsal setae. Pleotelson rectangular, elongate, more than half length of pleon, nearly twice as long as wide, with antero- and mid-lateral bulges and stepped at insertion of uropods; sparse lateral setae, pairs of dorsal setae level with lateral swellings and uropod insertions.

Antennule ( Fig. 1C ) proximal peduncle article 4.5 times as long as wide, with three inner setae longer than article width, and conspicuous pointed distal apophysis with adjacent plumose and simple setae as figured; second article nearly twice as long as wide, less than one third length of first and bearing groups of inner and outer plumose distal setae; third article half length of second, nearly twice as long as wide; fourth peduncle article shorter than third, wider than long. Main flagellum of 23 segments, single aesthetascs present on segments 7, 8, 10, 14, 16, 18 and 20; accessory flagellum of five segments.

Antenna ( Fig. 1D ) with simple, naked proximal peduncle article. Second article with inner and distal spine-like apophyses, and with elongate squama bearing three long and two short marginal setae. Third peduncle article shorter than wide with long inner seta; fourth article longest, as long as first three articles together, fifth article 3/4 as long as fourth. Flagellum of 13 segments.

Simply pointed epistome present ( Fig.1B ). Labrum rounded, simple, setose.Left mandible( Fig. 1E ) with strong, crenulate pars incisiva, insignificant lacinia mobilis, setiferous lobe with one bifurcate and four trifurcate setae, pars molaris stout, blunt with fine outer setation; palp of three articles, proximal article with three inner and one outer setae; second article twice as long as first with three rows of inner setae in its distal half; third article half length of second, with 15 inner setae increasing in length to distal pair, and two denticulate mesial spines dorsally. Right mandible as left but without lacinia mobilis. Labium ( Fig. 2C ) with setulose outer and inner margins, distally involuted, palp with outer serrations, fine lateral setules and three simple distal setae. Maxillule ( Fig. 2A ) inner endite with inner and outer apophyses, finely setose margins and five plumose distal setae, outer endite with ten distal spines and two subdistal setae, outer and inner margins finely setose, palp of two articles, distally with two long setae, subdistally with one short simple seta and four longer distally-setulose setae. Maxilla ( Fig. 2B ) typical of the genus, moveable endite virtually fused, fixed endite with bifurcate distal spines, other spines and setae simple, rostral row of 21 setae. Maxilliped ( Fig. 2D ) basis rounded, naked; first palp article with longer, plumose inner distal seta and simple outer seta; second palp article with inner margin bearing numerous shorter simple setae each about half length of sparser plumose setae, and simple outer distal seta; third palp article wider than long with densely setose inner-distal margin; fourth palp article with seven finely denticulate and one simple distal setae. Endite ( Fig. 2E ) with three coupling hooks, distally with outer simple and inner blunt setae, inner caudodistal seta simple, blunt. Epignath ( Fig. 2F ) large, cup-shaped, with prominent distally-setose spine.

Cheliped ( Fig. 2G ) compact, basis 1.5 times as long as wide, ventrally with fine proximal seta, stout central spine and row of four distal setae; threearticled exopodite present, distal article with seven plumose setae. Merus subrectangular, mid-ventrally with prominent tubercles and simple setae; carpus compact, about as long as wide, ventrally with blunt tubercles interspersed with simple setae. Chela stout, palm (propodus) just longer than wide; fixed finger with central tooth-like apophysis and small distal denticulations on cutting edge, and numerous distal and ventral setae; dactylus as long as palm, curved, with no apophyses on cutting edge.

Pereopod 1 ( Fig. 3A ) bearing pronounced coxal spine-like apophysis with two plumose distal setae; basis 2.9 times as long as wide, with small ventrodistal spine and one longer and one shorter seta; exopodite small, three-articled, distal article with eight plumose setae. Ischium with two ventrodistal setae. Merus wider distally, with smaller ventrodistal and longer dorsodistal spines, setose as figured. Carpus compact, shorter than merus, longer than wide, with two ventral and one dorsodistal spines; dorsodistal pair of setae and inner row of four smaller setae, three ventral marginal setae. Propodus with three ventral slender blunt spines interspersed with setae, middorsal and dorsodistal slender blunt spines amongst sparse setae, compound pectinate seta at base of dactylus. Dactylus stout, with fine ventral denticulations; unguis short, distinct.

Pereopod 2 ( Fig. 3B ) basis four times as long as wide, with fine dorsal and ventral marginal setae and longer plumose ventrodistal seta; ischium with smaller dorsal seta and two longer plumose ventrodistal setae; merus as long as carpus, with simple ventral setae, two plumose dorsodistal setae and ventrodistal slender blunt spine; carpus with six dorsodistal setae, and single ventrodistal blunt spine, small mesiodistal blunt spine, and smaller submarginal ventral spines; propodus slender, sparsely setose, with row of five ventral spines, single dorsodistal spines and two smaller spines on anterior face; dactylus finely denticulate and with small dorsal seta, unguis distinct. Pereopod 3 ( Fig. 3C ) similar to pereopod 2, but carpus longer than merus, propodus with three ventral spines.

Pereopod 4 ( Fig. 3D ) basis stouter, three times as long as wide, with long ventrodistal seta; carpus nearly twice as long as merus and with three pairs of ventral spines and longer mesiodistal spine; propodus with distal crown of five setae, one as long as dactylus. Pereopod 5 ( Fig. 3E ) more slen- der than pereopod 4, basis with dorsal and ventral marginal plumose setae; carpus as long as merus and with four dorsal plumose setae, distal three grouped; merus with two anterior plumose setae; propodus with row of 12 short, fine spines distally. Pereopod 6 ( Fig. 3F ) with marginal plumose setae dorsally on basis and single ventrodistal plumose seta; fine ventral setae short and simple; merus with single dorsal plumose seta; carpus with three dorsal plumose setae; propodus ventral margin with row of some 11 small compound spines not extending to distal margin, dorsodistal group of two blunt spines and single seta.

Pleopods ( Fig. 1F ) all alike, basis with three inner plumose setae, outer margin naked; rami slender, endopod slightly longer than exopod, respectively with 17 and 15 marginal plumose setae, inner proximal seta of endopod with trifurcate tip.

Uropod biramous, basis with two outer and one inner distal setae; exopod three times as long as basis and of seven apparent segments, distal setae as long as exopod; endopod elongate, filiform, multisegmented, 2.5 times as long as pleotelson.

Male

Body length 7.0 mm, closely similar to female;ventral penial tubercle on pereonite 6 pointed and directed ventrally. Cheliped carpus with more prominent, pointed apophyses on ventral margin.

REMARKS

Despite the number of inappropriate species which have been attributed to the genus in the past, there are few species of Apseudes recorded from Pacific waters. Apseudes spectabilis Studer, 1883 is known from Japan and the Subantarctic at depths of 13- 387 m. A. tropicalis Miller, 1940 was recorded from Hawaii (?littoral), while A. vitjazi Kudinova-Pasternak, 1970 is a deep North Pacific species, recorded from 5050-5095 m. Shiino (1963) described two new species from Vietnam, A. nhatrangensis Shiino, 1963 (38-43 m) and A. nagae Shiino, 1963 ( Vietnam and Brunei,?littoral to 60 m).

None of these species has the scooped, downcurving rostrum nor the spinose apophysis on antennule peduncle article 1. Down-curving rostra are not unusual in Apseudes species (e.g., A. spinosus (M. Sars, 1858)) , but these do not have the uniform concavity of the present species. Conversely, spinelike apophyses on the antennule peduncle are hardly recorded: Hoplomachus propinquus (Richardson, 1903) , a species moved from Apseudes by Guţu (2002), has a similar apophysis, but also has others along the interior margin of the same article, and a number of other features which caused Guţu to reassign its generic status, but which do not occur in A. batillus n. sp.

Figures

FIG. 1. — Apseudes batillus n. sp.: A, holotype ♂, dorsal; B, cephalon, lateral; C, antennule; D, antenna; E, left mandible; F, pleopod. Scale bar: A, B, 2 mm; C, D, F, 0.6 mm; E, 0.3 mm.

FIG. 2. — Apseudes batillus n. sp.: A, maxillule; B, maxilla; C, labium; D, maxilliped palp; E, maxilliped endite; F, epignath; G, right cheliped. Scale bar: A-F, 0.3 mm; G, 0.6 mm.

FIG. 3. — Apseudes batillus n. sp.: A-F, pereopods 1-6 respectively. Scale bar: 0.6 mm.