Pakistanapseudes turkoroa, Błażewicz-Paszkowycz, Magdalena & Bamber, Roger N, 2007

Błażewicz-Paszkowycz, Magdalena & Bamber, Roger N, 2007, Parapseudid tanaidaceans (Crustacea: Tanaidacea: Apseudomorpha) from Eastern Australia, Zootaxa 1401, pp. 1-32 : 8-14

Pakistanapseudes turkoroa sp. nov. ( Figs 4 , 5 )

Diagnosis: (male) rostrum truncated, flattened, eyes present; ventral margins of the merus, carpus and propodus and dorsodistal tip of the dactylus of pereopod 1 with fleshy dendritic structures. Dactylus of pereopod 2 slender, curved, elongate, 2.5 times length of propodus. Proximal antennule article only 1.3 times as long as wide. Pleopod basis wide, with six ventral and five dorsal plumose seta. Uropod exopod with six segments bearing elongate outer setae.

Material examined. 1 subadult male, holotype (QM W28162) muddy sand with fine shell breccia, Moreton Bay, 27º28.66’S 153º21.34’E, depth 7.2 m, 35‰, 29ºC, 11 Feb 2005; van Veen grab; coll. R.N.B.

Etymology. “Turkrooa” is the Australian aboriginal name for Peel Island, in Moreton Bay just south of the collection point for this species.

Description. Male (holotype appendages drawn in situ). Body ( Fig. 4 A), dorsoventrally flattened, attenuate, holotype 3.2 mm long (tip of rostrum to posterior of pleotelson), 6.6 times as long as wide, tapering towards posterior. Cephalothorax subrectangular, just wider than long, with pronounced flattened rostrum; eyelobes distinct, eyes present. Six free pereonites; pereonite 2 shortest, 0.4 times as long as cephalothorax, pereonites 1 and 6 subequal, 1.1 times length of pereonite 2; pereonite 4 longest (1.5 times pereonite 2), pereonites 3 and 5 just shorter than pereonite 4 (all pereonites respectively 2.3, 2.3, 1.5, 1.1, 1.2 and 1.5 times as wide as long); pereonites 1–3 laterally smoothly convex, pereonites 4–6 laterally straight, each with one or two short anterolateral or mid­lateral setae. Pleon 0.4 times length of whole animal, of five free subequal pleonites bearing pleopods; pleonites 1.5 times as wide as long, each with two small midlateral setae. Pleotelson ( Fig. 4 B) pentangular, as long as wide ands 1.5 times as long as pleonite 6, with one midlateral seta on each side, one pair of dorsal setae just posterior of midline, ands one pair of fine setae at posterior tip.

Antennule ( Fig. 4 C) compact. Proximal peduncle article short, 1.3 times as long as wide, with inner and outer lateral distal setae not longer than article width, longest distal seta reaching half length of peduncle article 2. Article 2 twice just longer than wide, two­thirds length of article 1 with inner and outer distal setae exceeding tip of third article. Article 3 one­third length of second, twice as wide as long; fourth peduncle article shorter than third. Main flagellum with secondary multisegmentation in proximal half, thus of eleven segments, single aesthetascs present on segments 7 and 9; accessory flagellum of seven segments.

Antenna ( Fig. 4 D) showing initial stages of secondary multisegmentation; simple, naked proximal peduncle article. Peduncle article 2 bearing elongate squama with seven marginal setae. Peduncle article 3 and 4 articles much shorter than wide, naked. Flagellum proximally not fully segmented, outer setae indicating an ultimate 14 segments; without aesthetascs.

Mouth parts. Epistome not conspicuous; labrum rounded, simple. Right mandible ( Fig. 4 E) with multidentate pars incisiva; setiferous lobe with one bifurcate and three simple setae, pars molaris stout, blunt with distal rugosity. Palp of three articles, article 3 with four inner distal setae; second article twice as long as first with four inner setae; third article as long as first, with two longer distal and two shorter sub­distal setae. Other mouthparts not clearly seen.

Cheliped ( Fig. 5 A) not as slender as typical for Pakistanapseudes , basis 1.5 times as long as wide, ventrally with single subdistal seta. Exopodite not seen. Merus subrectangular, with three longer and three shorter ventral subdistal setae. Carpus nearly three times as long as wide, dorsodistally one simple seta and, ventrally with four shorter and five longer simple setae. Chela relatively compact, palm (propodus) 1.5 times as long as wide with array of five distal and one ventral setae; fixed finger without apophyses but with small setules on cutting edge, and with one ventral and three inner lateral setae. Dactylus shorter than palm, curved, with simple setules cutting edge.

Pereopod 1 ( Fig. 5 B) with fleshy dendritic structures on ventral margins of merus, carpus and propodus and distally on dactylus. Basis twice as long as wide, with small dorsoproximal seta and longer ventrodistal seta. Exopodite conspicuous, 3­articled, distal article with six plumose setae. Ischium with two ventrodistal setae. Merus wider distally, with single blunt ventrodistal spine and adjacent dendritic structure, inner row of simple setae at mid­length, sparse distal setae as figured. Carpus compact, shorter than merus, as long as wide, with four ventral and one dorsodistal blunt spines, dendritic structure midventrally, two ventral and three dorsodistal setae. Propodus ( Fig. 5 C) with three ventral blunt spines interspersed with setae and three dendritic structures, two dorsodistal and one ventrodistal blunt spines and dorsodistal seta as long as dactylus plus claw. Dactylus stout, with small ventral denticulation, distally with ventral seta and dorsal dendritic structure; unguis distinct, short.

Pereopod 2 ( Fig. 5 D). Basis 3.4 times as long as wide, with single middorsal and ventrodistal setae. Ischium compact with single ventrodistal and shorter dorsodistal setae. Merus, carpus and propodus subequal; merus and carpus with ventrodistal slender blunt spine and two simple setae. Carpus dorsally with three distal setae. Propodus with two dorsodistal spines and adjacent longer simple setae, single ventrodistal spine adjacent to dactylus; dactylus ( Fig. 4 F) slender, curved, elongate, 2.5 times length of propodus.

Pereopod 3 ( Fig. 5 E). Basis 2.3 times as long as wide with two simple distal setae. Ischium as long as merus. Merus with small ventrodistal blunt spine. Carpus twice as long as merus with single ventrodistal spine and distal crown of simple setae. Propodus shorter than carpus, dorsoventral margin setose. Dactylus ( Fig. 4 F) shorter than propodus, distally bifurcate.

Pereopod 4 missing from specimen.

Pereopod 5 ( Fig. 5 F). Merus two­thirds length of subequal carpus and propodus, all three ventrally setose. Propodus with two small distal blunt spines. Dactylus two thirds length of propodus, simple (as that of pereopod 6, see Fig. 4 F).

Pereopod 6 ( Fig. 5 G) with article proportions similar to those of pereopod 5. Propodus ventral margin with row of 13 small leaf­like spines not extending to proximal margin, dorsodistal group of eight slender blunt spines surrounding dactylus. Dactylus ( Fig. 4 F) shorter than propodus with distal inner setule and indication of articulation of claw.

Pleopods ( Fig. 4 G) all alike. Basis with six ventral and five dorsal plumose seta. Rami linguiform. Endopod wider than exopod and with thirteen inner and one outer marginal plumose setae. Exopod with 16 marginal plumose setae.

Uropod ( Fig. 4 B) biramous. Basis with distal crown of six simple and one plumose sensory setae. Exopod nearly three times as long as basis and of six segments, distal five segments with elongate outer and (on distal segment) distal setae. Endopod missing.

Female unknown.

Remarks. The development of the antenna and antennule of this single specimen indicate it is a subadult male: both show the unfinished secondary multisegmentation characteristic of this genus, but are as yet without the array of aesthetascs which those segments would have supported eventually. Bamber and Sheader (2003) indicated that often species of Pakistanapseudes show sexual dimorphism of the cheliped when males are fully mature, so the cheliped morphology of the present specimen (without apophyses on the cutting edges of the fingers) probably reflects that of the female.

Despite this, there are features of the morphology of this species which make it quite distinct from those species of the Pakistanapseudes ­group described previously (or herein). The truncated rostrum is unique in the group, other species having either a rounded rostrum (e.g. P. perulpa , Fig.1 A) or one with a distal point (e.g. P. australianus Guţu, 2006 , Fig. 6 A). The dendritic fleshy, presumably sensory, structures on the ventral margins of the merus, carpus and propodus of pereopod 1 are also unique for the genus (and for the order!); that on the dorsodistal tip of the dactylus is clearly not analogous to the sensory setae found in the Kalliapseudidae . In addition, the short proximal antennule article, the very long dactylus­plus­unguis of pereopod 2, the uropod exopod presenting a comb of outer setae, and the wide basis of the pleopods are unusual features within the genus. We believe the exopodite on the cheliped to have been unseen in the temporary preparation of the single holotype rather than absent: although the aberrant Brazilian deep­sea species Leptolicoa thokozele ( Bamber & Sheader 2003) has no exopodite on pereopod 1, it and all other described species have an exopodite on the cheliped.

Pakistanapseudes australianus Gu ţ u, 2006 ( Fig. 6 )

Pakistanapseudes australianus, Guŀu, 2006 , pp. 260–264, figs 511–525.

Material examined. 1 female with oostegites (QM W28154), sandy mud, Moreton Bay, 27º22.72’S 153º19.43’E, depth 15 m, 35‰, 29.4ºC; 1 female?, no legs (QM W28155) muddy sand with spatangoids, Moreton Bay, 27º20.91’S 153º19.96’E, depth 16.6 m, 33‰, 29.1ºC; both 10 Feb 2005, van Veen grab; coll. R.N.B.

Remarks: P. australianus is one of five described species of the Pakistanapseudes ­group with a pointed rostrum and pigmented eyes ( Fig. 6 A) and a simple dactylus and unguis to pereopod 2, although in all of the other four ­ P. hodgsoni Bamber, 2000 , from Hong Kong, P. shiinoi Băcescu, 1978 , from the Gulf of Aden, Biropalostoma spiniferum Guţu and Angsupanich, 2004 from Thailand, and P. pectinis (Bamber 1998) from Brunei ­ the rostrum has rounded “shoulders” either side of a terminal point, unlike the present species. Some aspects of the morphology of the 2005 specimen show slight variation with the holotype description, and the opportunity is taken to add features not described by Guţu (2006).

Supplementary description:

Mouth parts. Epistome blunt. Labrum rounded, simple. Labium ( Fig. 6 B) with outer serrations, not setose, palp with inner rounded apophysis, setulate margins and two simple distal setae. Maxillule ( Fig. 6 C) inner endite with outer apophysis, and one simple and three compound distal setae. Maxilliped ( Fig. 6 D) with simple setae; first palp article with short outer seta only; second palp article with inner margin bearing dense setae largely in two rows, and one short and one long outer distal seta, outer seta reaching tip of fourth article; third palp article with nine setae largely in two rows; fourth palp article with five distal setae and one shorter, outer subdistal seta. Epignath ( Fig. 6 E) large, cup­shaped, with serrate spine.

Pereopod 2 ( Fig. 6 F). Basis 5.5 times as long as wide, with ventrodistal tuft of setae. Ischium compact. Merus half length of carpus, with simple ventrodistal setae. Carpus with mesial and dorsodistal setae and ventrodistal slender, blunt spine with marginal serrations. Propodus slender, distally setose and with slender ventrodistal and distal serrated spines. Dactylus slender with small ventrodistal seta, unguis distinct, both together as long as propodus.

Pereopod 3 missing.

Pereopod 4 ( Fig. 6 G). Basis stouter, three times as long as wide, with short ventroproximal seta and long ventrodistal seta. Ischium with single short dorsal seta, and one short and one longer ventrodistal setae. Merus twice as long as ischium, sparsely setose. Carpus 1.7 times as long as merus, setae sparse but with single midventral and two ventrodistal spines. Propodus with two short ventrodistal and two longer dorsodistal serrated spines. Dactylus plus unguis not fused, shorter than propodus or dorsodistal spines and setae. Pereopod 5 similar to pereopod 4; dactylus plus unguis as long as adjacent setae. Pleopods basis with two or three dorsal plumose setae (two on pleopod 1) and none or one ventral plumose seta.

Uropod biramous, multisegmented. Basis with crown of four distal setae. Exopod four times as long as basis. Endopod elongate, filiform, as long as body except for cephalothorax, five times as long as exopod.

Figures

FIGURE 1. Pakistanapseudes perulpa sp. nov., A, holotype female, dorsal; B, pleotelson and uropod exopod; C, antennule; D, antenna; E, left mandible, distal; F, right mandible; G, maxillule; H, maxilla; I, epignath; J, labium. Scale line = 1.5 mm for A, 0.3 mm for B­D, 0.2 mm for E – J.

FIGURE 4. Pakistanapseudes turkoroa sp. nov., A, holotype male, dorsal; B, pleotelson, dorsal, with pereonite 6 and left uropod exopod; C, antennule; D, antenna; E, right mandible; F, dactyli of pereopods 2, 3 and 6; G, pleopod 4 (plumose nature of basis setae, and setae of rami not shown, for clarity). Scale line = 1 mm for A, 0.3 mm for B – E and G, 0.1 mm for F.

FIGURE 5. Pakistanapseudes turkoroa sp. nov., holotype male, A, cheliped; B, pereopod 1; C, propodus and dactylus of pereopod 1 (setae omitted for clarity); D to G, pereopods 2 and 3, 5 and 6 respectively. Scale line = 0.3 mm for A, B and D – G, 0.1 mm for C.

FIGURE 6. Pakistanapseudes australianus, 2005 specimen: A, body, dorsal; B, labium; C, maxillule; D, maxilliped palp; E, epignath; F, pereopod 2; G, pereopod 4. Scale line = 1.5 mm for A, 0.2 mm for B to G.