Pakistanapseudes taylorae, 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 : 45-50

Pakistanapseudes taylorae sp. nov.

Figures 30–32

Material examined. 1 with oostegites (J57588), holotype, Stn BSS76 , Western Bass Strait , 39º19'S 143º38'E, 95 m depth, 10 October 1980, coarse sand,carbonate,coll. G C B Poore; 1juvenile without appendages (J57596), paratype, Stn BSS112 , Central Bass Strait , 40º22.2'S 145º17'E, 40 m depth, 3 November 1980, mainly sand, coll. M.F. Gomon and G C B Poore; 3, 3 (J55840), paratypes, Stn BSS180 , Central Bass Strait , 39º12.9'S 146º27.3'E, 65 m depth, 18 November 1981, medium sand, coll. R. S. Wilson; 1 brooding (J55865), paratype,Stn CPBS 32 N, Western Port, 38º20.83'S 145º13.49'E, 13 m depth, 21 February 1969, sandy gravel. 1 (not registered), Stn BSS209 , Eastern Bass Strait, 38º18.0'S 147º37.0'E, 55 m depth, 31 July 1983, muddy with fine shell, coll. M. Gomon & R. S. Wilson .

Description of female. Body ( Fig. 30A), dorsoventrally flattened, elongate, holotype 4 mm long (tip of rostrum to posterior of pleotelson), 6.5 times as long as wide, tapering towards posterior. Cephalothorax subrectangular, just wider than long, with pronounced apparently rounded rostrum but with small distal point ( Fig. 31C), single lateral setae in front of branchial chamber on each side; eyelobes distinct, dark ocelli present. Forward or backward pointing hyposphenium mid-ventrally between chelipeds. Pereonite 1 naked, pereonites 2 and 3 with anterolateral seta, pereonites 4 to 6 with anterolateral seta and posterolateral seta; pereonite 1 shortest, about 0.4 times as long as cephalothorax, pereonites 2 and 3 subequal, half length of cephalothorax; pereonite 4 longest, 1.3 times as long as pereonite 1, pereonite 5 just shorter than pereonite 4, pereonite 6 just longer than pereonite 1 (all pereonites respectively 2.6, 1.8, 1.7, 1.1, 1.2 and 1.7 times as wide as long); pereonites 1 and 2 with or without hyposphenia. Pleon three times as long as pereonite 4, with five free pleonites bearing pleopods; pleonite 1- 0.4 times as long as wide, posterior pleonites progressively shorter, each with four or five lateral setae. Pleotelson rectangular, one-third length of pleon, twice as long as wide, with paired lateral setae.

Antennule ( Fig. 31A) proximal peduncle article 3.2 times as long as wide, outer margin with few shorter simple setae, inner margin with numerous penicillate setae and more sparse longer simple setae, longest seta reaching distal edge of second peduncle article. Second article 1.5 times as long as wide, half length of first, with distal crown of simple and penicillate setae. Article 3 about 0.2 times length of article 2, half as long as wide, with long distal setae all round. Peduncle article 4 as long as article 3, wider than long. Main flagellum regularly setose, of eight segments, single aesthetascs present on segments 6 and 8; accessory flagellum of five segments.

Antenna ( Fig. 31B) with naked proximal peduncle article expanded on inner margin. Article 2 just longer than first, with one simple seta adjacent to elongate squama bearing two distal setae. Peduncle article 3 shorter than wide with inner spine-like apophysis. Article 4 one-and-a-half times as long as second with crown of penicillate setae; article 5 just longer than article 4, with single distal seta. Flagellum of four segments.

Labrum ( Fig. 31D) truncate, simple, marginally setose. Pointed epistome obvious. Right mandible ( Fig. 31F) with five rounded “teeth” on pars incisiva; setiferous lobe with one bifurcate and three trifurcate setae, pars molaris ( Fig. 31F ") stout, blunt with crenulate distal margin; palp ( Fig. 31 F') of three articles, proximal article with one inner seta; second article nearly three times as long as first, naked; third article as long as second, with two longer and two shorter simple distal setae. Left mandible ( Fig. 31E) as right but with dentate lacinia mobilis and five setae on setiferous lobe. Labium ( Fig. 31I) without serrations, not setose, palp with inner and outer fine lateral setules and two longer and one minute simple distal setae, and widely rounded inner apophysis. Maxillule ( Fig. 31G) inner endite with outer finely-setose margin distal of apophysis, and four plumose and one simple distal setae; outer endite with ten distal spines and three subdistal setae, outer margin finely setose; palp of two articles. Maxilla ( Fig. 31H) typical of genus, outer margin naked, outer lobe of moveable endite with two subdistal and seven distal finely denticulate setae, inner lobe with nine plumose/denticulate setae; fixed endite outer lobe with simple, trifurcate, plumose and bilaterally denticulate distal spines, inner lobe with two longer plumose setae and rostral row of 13 setae. Maxilliped ( Fig. 31J) mostly with simple setae; first palp article with short outer distal seta and longer inner distal seta almost reaching tip of article 2; second palp article with outer distal spine, inner margin bearing 16 setae largely in two rows, longest inner seta reaching fourth article, inner proximal margin with about three thorn-like apophyses; third palp article with five recurved inner setae; fourth palp article with seven setae around distal margin, inner five with finely denticulate inner margins. Endite ( Fig. 31 J') distal margin with outer simple setae and gradation of inner blunt spines, caudal seta leaf-like. Epignath ( Fig. 31K) large, cup-shaped, with large, setose proximal lobe and distally setulose distal spine.

Cheliped ( Fig. 32B) only one available on one specimen, damaged; basis slender, 2.6 times as long as wide, ventrally with small proximal and longer distal setae, without spine. Exopodite damaged. Merus with three ventrodistal setae. Carpus slender, 3.3 times as long as wide, with one mid-ventral and two ventrodistal setae. Chela badly damaged, fixed finger with 3 ventral setae, and tuft of distal curled setae, and row of spatulate setae on cutting edge.

Pereopod 1 ( Fig. 32C) basis three times as long as wide, with small ventroproximal and mid-ventral spine and seta between these two, longer, pointed ventrodistal spine with adjacent seta exceeding distal margin of ischium, dorsal margin with two proximal simple setae and two mid-dorsal penicillate setae. Exopodite damaged. Ischium with three ventrodistal setae. Merus half as long as basis, wider distally, with slender dorsodistal spine and long dorsodistal seta as long as carpus, row of five ventral setae and ventrodistal spine. Carpus just shorter than merus, with three ventral spines interspersed with three setae, and one elongate dorsodistal spine with adjacent row of four setae. Propodus with five ventral spines increasing in length towards distal margin interspersed with single simple setae, two dorsodistal slender blunt spines and row of setae along dorsal margin. Dactylus stout, with three ventral denticulations, two small mid-dorsal setae. Unguis distinct, pointed.

Pereopod 2 ( Fig. 32D) basis 2.7 times as long as wide, with single mid-ventral spine and three elongate ventrodistal setae. Ischium as long as wide with row of three ventrodistal setae; merus shorter than carpus, with single long, slender dorsodistal and ventrodistal spines. Ventral margin with row of six setae, one ventrodistal seta. Carpus 1.5 times as long as merus, with row of three slender spines interspersed with single setae along ventral margin, and diagonal row across inner face of two spines and six setae, one longer, slender dorsodistal spine; propodus just longer than carpus, ventrodistal margin with four slender spines interspersed with single simple setae, dorsally with three slender spines and five setae in distal half. Dactylus slender, together with distinct unguis 0.8 times as long as propodus, not bifurcate. All spines with fine denticulation in distal half.

Pereopod 3 ( Fig. 32E) similar to pereopod 2, but basis more slender, merus with only one ventral spine and without dorsal spine, carpus and propodus with fewer spines and setae, dactylus 1.24 times as long as propodus, very small unguis subdistal, giving bifurcation.

Pereopod 4 ( Fig. 32F) basis 4.3 times as long as wide, with ventrodistal and dorsoproximal penicillate setae and single, long ventrodistal simple seta exceeding tip of merus. Ischium with single ventrodistal seta. Merus with three ventral setae. Carpus 1.5 times as long as merus, ventrally with four slender, blunt, finely denticulate spines interspersed with nine setae. Propodus with distal crown of ten setae, single dorsal penicillate seta in proximal half; dactylus elongate, sinuous, pointed, 1.6 times as long as propodus.

Pereopod 5 ( Fig. 32B) similar to pereopod 4 but basis without ventrodistal seta, ventral setae on ischium and merus shorter, unguis attached subdistally, shorter than extension of dactylus, giving bifurcation.

Pereopod 6 ( Fig. 32H) basis naked, ischium with two ventrodistal setae and single smaller dorsodistal seta. Carpus with eight setae and five denticulate spines ventrally. Propodus ventral and distal margin with row of some 26 small leaf-like spines, ventrally with slender subdistal spine, dorsodistal group of two setae. Dactylus as long as propodus, unguis attached subdistally, shorter than extension of dactylus, giving bifurcation.

Pleopods ( Fig.30B) all alike. Basis with two outer plumose setae and three inner plumose setae; rami linguiform. Endopod longer than exopod, respectively with 17 and 13 marginal plumose setae.

Uropods missing on all specimens.

Description of male. Generally similar to female, available specimens missing most appendages (cheliped unknown); antennule missing, antenna ( Fig. 32A) with multisegmented flagellum with array of aesthetascs over whole surface; squama with three distal setae.

Etymology. named after Dr Joanne Taylor, Collection Manager at Museum Victoria, in gratitude for all her diligent efforts and her tolerance of our interference with her collections.

Remarks. Pakistanapseudes taylorae sp. nov. is the seventh species of this genus recorded from Australian waters (see Błażewicz-Paszkowycz & Bamber, 2007, and above). The only other species to have a pointed rostrum and bifurcate claws is P. lucifer (described above); the present species is distinguished from P. lucifer by having basal setae on the pleopod, a very short third peduncle article on the antennule, a non-bifurcate claw on pereopods 2 and 4, far more and longer setae and spines on the cheliped and pereopods, fewer segments in the flagellum of the antenna and the main flagellum of the antennule, fewer setae on the distal maxilliped palp article, and the thorn-like apophyses on the second palp article, inter alia. Interestingly, both of these species have the unusual attribute of three subdistal setae on the outer endite of the maxillule.

Elsewhere, the only other species of the Pakistanapseudinae with a pointed (if only slightly) rostrum, eyes, and bifurcate pereopod claws is Swireapseudes birdi from the Bahamas, but that species has far more segments in the antennular and antennal flagella, far fewer spines on its much more slender pereopod 1, a proportionately longer third peduncle article on the antennule, and distinct setation of its mouthparts.

P.taylorae is particularly unusual in the Pakistanapseudinae in the reduced setation of the antennal squama: only the deep-sea species Leptolicoa thokozele ( Bamber & Sheader, 2003) , very distinct from the present species in a number of features, has as few as two squama setae.

P. taylorae was collected sparsely throughout Bass Strait, on coarse to medium sands, and in depths between 13 and 95 m.