Paradoxapseudes attenuata, Błażewicz-Paszkowycz & Bamber, 2012

Błażewicz-Paszkowycz, M. & Bamber, R. N., 2012, The Shallow-water Tanaidacea (Arthropoda: Malacostraca: Peracarida) of the Bass Strait, Victoria, Australia (other than the Tanaidae), Memoirs of Museum Victoria 69, pp. 1-235 : 21-25

Paradoxapseudes attenuata sp. nov.

Figures 13–15

Gollumudes larakia Błażewicz-Paszkowycz & Bamber, 2007b

(partim – deeper-water specimens), non- Apseudes larakia Edgar, 1997 .

Material: 1 (J47130), holotype, Stn BSS109 , Central Bass Strait, 40º30.9'S 144º56'E, 27 m depth, 2 November 1980, very coarse sand, coll. M. Gomon & G.C.B. Poore ; 2 with oostegites (J55843), paratypes, Stn BSS117 , Central Bass Strait, 40º38.0'S 145º23'E, 36 m depth, 4 November 1980, muddy shell and grit, coll. M. Gomon & G.C.B. Poore ; 1 (J58464), paratype, Stn BSS161 , Central Bass Strait, 39º48.3'S 147º19.2'E, 60 m depth, 14 November 1981, muddy sand, coll. R. Wilson .

Other material: 2 (J55842), Stn BSS119 , western Bass Strait , 39º06.7'S 143º28.7'E, 92 m depth, 31 January 1981, fine sand, coll. M. Gomon et al.; 1 (J57559), Stn VC 18 C2, Central Bass Strait , 38º30.2'S 144º15.0'E, 40 m depth, 30 May 1998, coll. N. Coleman, Smith McIntyre grab. Material in Błażewicz-Paszkowycz & Bamber (2007b): 4 individuals (J47131), Australia, Tasmania, eastern Bass Strait , 37 km NNE of Eddystone Point (40º43.48'S, 148º37.12'E), 67 m, 14/11/1981, ( BSS 164 ) , coll. R.S. Wilson; 1 individual (J55756), western Bass Strait , 30 km SSW of Warrnambool (38º38.12'S, 142 35.00'E), 59 m, 20/11/1981, ( BSS 188 ), coll . R.S. Wilson; 3 individuals (J55757), western Bass Strait , 15 km S of Port Fairy (38º32.00'S, 142 28.36'E), 52 m, 20/11/1981, ( BSS 187 ), coll . R. S. Wilson; 1 individual (J55760), western Bass Strait, 15 km south of Port Fairy (38º32.00'S, 142 28.36'E), 52 m, 20/11/1981, ( BSS 187 ), coll . R. S. Wilson; 2 individuals (J55766), Victoria, western Bass Strait, 5 km south of Point Reginald (38º48.00'S, 143º14.30'E), 47 m, 20/11/1981, ( BSS 185 ), coll . R.S. Wilson; 1 individual (J55758), western Bass Strait, 5 km southwest of Bluff Point (40º48.06'S, 144º38.00'E), 42 m, 02/02/1981, ( BSS 126 G), coll. M.F. Gomon.

Description of female with oostegites. Body ( Fig. 13) dorsoventrally flattened, elongate, holotype 2.75 mm long, seven times as long as wide, tapering towards posterior. Cephalothorax subrectangular, 1.5 times as long as wide, with triangular rostrum; eyelobes and eyes present. Pereonite 1 laterally convex, 0.23 times as long as cephalothorax; pereonite 2 1.2 times as long as pereonite 1, with slight anterolateral apophysis bearing plumose seta, smaller posterolateral plumose seta; pereonites 3 to 6 with anterolateral pointed apophyses and posterolateral rounded apophyses, each bearing plumose setae, pereonites 3 and 5 subequal, 1.8 times as long as pereonite 1, pereonite 4 longest, twice as long as pereonite 1, pereonite 6 as long as pereonite 2 (all pereonites respectively 2.9, 2.3, 1.5, 1.2, 1.4 and 1.9 times as wide as long). Pleon narrower than pereon, just longer than cephalothorax, tapering posteriorly, with five free subequal pleonites bearing pleopods; each pleonite about 3.3 times as wide as long and extended laterally into sharp, triangular apophysis bearing plumose setae. Elongate pleotelson subpentangular, with two rounded apophyses bearing plumose setae on each side, as long as last four pleonites together, 1.75 times as long as wide.

Antennule ( Fig. 14A) proximal peduncle article 4.2 times as long as wide, outer margin with slight proximal rounded apophysis, three penicillate setae and three simple setae in distal half, inner margin with sparse simple setae, no proximal corrugation; second peduncle article twice as long as wide, 0.4 times as long as first, with two penicillate and five simple distal setae; third article half length of second, about twice as long as wide; fourth peduncle article slender, slightly shorter than third. Main flagellum of 7 segments, single aesthetasc present on sixth segments, seventh segment anaxial on sixth; accessory flagellum of three segments.

Antenna ( Fig. 14B), proximal peduncle article with inner apophysis bearing small seta and two teeth. Second peduncle article twice as long as first, twice as long as wide, margins sinuous with mid-inner setae on apophysis, with elongate linguiform squama bearing 6 marginal setae. Third peduncle article as long as wide and one-quarter as long as second, fourth article 0.8 times as long as second, fifth article half length of second. Flagellum of five segments.

Labrum ( Fig. 14C) rounded, simple, distally with rows of setules. Left mandible ( Fig. 14D) with strong, crenulate pars incisiva, robust lacinia mobilis with five distal crenulations, setiferous lobe with four slender setae; pars molaris robust, with radial rows of distal rugosity; palp ( Fig. 14 D') of three articles, proximal article shortest with six simple setae, second article longest with four distomedial simple setae, third article with six distal setae. Right mandible ( Fig. 14E) similar but without lacinia mobilis. Labium ( Fig. 14H) with denticulate outer margin, setulose distal margin, palp with fine lateral setules and one simple distal seta. Maxillule ( Fig. 14F) inner endite with slight outer apophysis, finely setose outer margin and four setulose distal setae, outer endite with eleven distal spines and two subdistal setae, outer and inner margins finely setose, palp of two articles, distally with one short and one longer setae. Maxilla ( Fig. 14G) outer lobe of moveable endite with two simple subdistal sickle-like setae and five distal setulose setae, inner lobe with eight simple curved setae and five stouter plumose setae; outer lobe of fixed endite with six compound distal spines and subdistal biserrate spine, inner lobe with three stout, serrate and proximally setulose setae and rostral row of 15 setae. Maxilliped ( Fig. 14I) basis naked; first palp article with one very long plumose inner seta and small outer seta; second palp article with artefactual suggestion of proximal articulation, longer than wide, with four proximal inner plumose setae and rows of inner curved setae in distal half, mostly plumose; third palp article nearly twice as long as wide, with inner group of six simple curved setae; fourth palp article with one subdistal and seven distal simple setae. Endites ( Fig. 14 I') with two coupling hooks, outer margin densely setulose, distally with one simple seta and numerous slender, blunt, bifurcate spines. Epignath ( Fig. 14J) oval, with setose distal spine.

Cheliped ( Fig. 15A) basis twice as long as wide, ventrally with central sharp seta and distal pair of simple setae; three-articled exopodite present, slender, distal article with four plumose setae. Merus with small spine and two simple setae on ventrodistal “shoulder”; carpus 2.4 times as long as wide, with ventral marginal setae and single dorsodistal seta. Chela stout, fixed finger as long as palm with six ventral setae, cutting edge setose and with proximal tooth-like apophysis; dactylus and claw slightly overreaching fixed finger, with fine setules on cutting edge.

Pereopod 1 ( Fig. 15B) with conspicuous setose apophysis on coxa; basis three times as long as wide, dorsal margin bearing four simple setae in proximal half, ventral margin with single proximal, single mid-ventral and paired distal simple setae; exopodite three-articled, distal article with four plumose setae. Ischium with three simple ventrodistal setae. Merus widening distally, with ventroproximal row of simple setae, and single long dorsodistal and shorter ventrodistal finely-denticulate spines and associated simple setae. Carpus shorter than merus, with setose margins including paired dorsodistal setae longer than propodus, one dorsodistal and two ventrodistal finely-denticulate spines. Propodus just shorter than carpus, with two dorsodistal and four ventral finely-denticulate spines interspersed with single fine setae. Dactylus slender, claw short.

Pereopods 2 and 3 ( Fig. 15C, D) basis four times as long as wide, sparsely setose, ventrodistal setae reaching to half length of merus; ischium half as long as wide, with fine dorsal seta, one short ventral seta and one ventral seta longer than merus; merus shorter than carpus, with four ventral setae and single dorsodistal seta; carpus with slender ventrodistal spine with adjacent simple setae and long dorsodistal simple setae as long as article; propodus longer than carpus, with two or three slender ventral spines, dorsodistal setae as long as article; dactylus with ventrodistal seta, dactylus and claw slender, curved, together as long as propodus.

Pereopod 4 ( Fig. 15E) similar to pereopod 3 but with stouter basis just less than 3 times as long as wide, with penicillate seta and fine ventrodistal simple seta as long as ischium and merus combined; dactylus and claw less curved than those of anterior pereopods, one of dorsodistal setae longer than dactylus and claw combined.

Pereopod 5 ( Fig. 15G) similar to pereopod 4, but basis with three penicillate setae and three ventrodistal simple setae, propodus with one longer seta shorter than dactylus plus claw, and with ventral comb of 11 leaf-like spines in the distal half.

Pereopod 6 ( Fig. 15F) basis with four plumose dorsal setae; merus shorter than carpus but proportionately longer than on pereopod 5, with two dorsal plumose setae; carpus with one dorsal plumose seta; propodus with small leaf-like spines ventrally and distally; dactylus plus claw slender, curved, together as long as propodus

Pleopods typical for genus ( Fig. 15H), basis with two inner but no outer plumose setae, endopod with 12 plumose marginal setae, exopod shorter with eight plumose marginal setae.

Uropod ( Fig. 15I) biramous, basis with five distal simple setae; exopod about twice as long as basis and of four segments; endopod elongate, filiform, with about 17 segments.

Male unknown.

Etymology. From the Latin – attenuatus: long, drawn out, thin.

Remarks. Paradoxapseudes attenuata sp. nov. is one of only three species of the genus without plumose setae on the basis of pereopod 1 or proximal serration on the antennal peduncle, and with only two maxillule palp setae; of the other two, P. littoralis is distinct in having only two segments in the accessory flagellum and four in the main flagellum of the antennule (three and seven respectively in the other two), while P. mortoni (Bamber, 1997) has one fewer ventral propodus spine on pereopod 1, one fewer setae on the pleopod basis, one more distal seta on the labial palp, fewer setae on the proximal mandibular palp article, and ventral tubercles on the carpus of the female cheliped. The second antennal-peduncle article in the present species is unusual in widening at its midpoint where the setae attach, and in only having four ventral setae on the second article of the mandibular palp, all other species having at least 6. P. attenuata is one of the most elongate species in the genus, particularly in the proportions of its cephalothorax.

Paradoxapseudes attenuata was collected throughout the Bass Strait on sandy substrata at depths between 27 and 92 m.