Pugiodactylus syntomos, Błażewicz-Paszkowycz & Bamber, 2007

Błażewicz-Paszkowycz, M. & Bamber, R. N., 2007, New apseudomorph tanaidaceans (Crustacea: Peracarida: Tanaidacea) from eastern Australia: Apseudidae, Whiteleggiidae, Metapseudidae and Pagurapseudidae, Memoirs of Museum Victoria 64, pp. 107-148 : 131-132

Pugiodactylus syntomos sp. nov.

Figures 14–16

Material. Female, holotype ( NVM J55749 ), Australia , Tasmania, western Bass Strait , 59 km W of Stokes Point, King I. (40°07'S, 143°14'E), 185 m, 11/10/1980, ( BSS 104 G), G.C.B. Poore . Paratypes: 2 females, 1 male ( NVM J47118 ) , same locality as holotype; 1 specimen dissected on slides ( NVM J55941 ), western Bass Strait , King I ., 59 km W of Stokes Point (40°07'S, 143°14'E), 185 m, 11/10/1980 ( BSS 104 ), G.C.B. Poore; 4 individuals ( NMV J55786 ), eastern Bass Strait , 70 km ENE of North Point, Flinders I. (39°28.24'S, 148°41.48'E), 110 m, 28/03/1979, ( BSS 35 ), G.C.B. Poore ; 1 female with rudimental oostegites, 3 males, 2 juveniles, 1 manca, ( NMV J55787 ), eastern Bass Strait , 85 km NE of North Point, Flinders I. (39°02.24'S, 148°30.36'E), 120 m, 15/11/1981, ( BSS 169 ), R.S. Wilson; 1 ovi female , 1 male, ( NMV J55788 ), Victoria, western Bass Strait , 5 km S of Point Reginald , Victoria (38°48'S, 143°14.30'E), 47 m, 20/11/1981, ( BSS 185 ), R.S. Wilson; 1 ovi females , 1 male ( NMV J55789 ) , 50 m S of Twin Reefs, Venus Bay (38°41'S, 145°39'E), 9 m, 07/03/1982, ( CPA 7 ), M. McDonald .

Description of female. Body (fig. 14), dorsoventrally flattened, elongate, holotype 2.6 mm long (tip of rostrum to posterior of pleotelson), 5.6 times as long as wide, narrower posteriorly. Cephalothorax subcircular, slightly longer than wide, naked, anterior margin with conspicuous triangular pointed rostrum. Eyes and eyelobes present. 6 free pereonites; pereonite 1 shortest, 0.3 times as long as cephalothorax, lateral margins straight, coxal apophyses of pereopod 1 evident; pereonite 2 1.25 times as long as pereonite 1 with rounded anterolateral tubercle on each side; pereonite 3 with anterolateral spine-like apophyses, 1.5 times as long as pereonite 1; pereonite 4 slightly longer than pereonite 3, subrectangular; pereonite 5 longest, twice as long as pereonite 1; pereonite 6 simple, narrowest, just longer than pereonite 1 (all pereonites respectively 2.7, 2.1, 1.5, 1.2, 1.0 and 1.6 times as wide as long). Pleon 2.5 times as long as pereonite 6, of 5 free subequal pleonites bearing pleopods plus pleotelson; pleonites more than 4 times as wide as long, laterally expanded by spiniform apophyses. Pleotelson pentagonal, half length of whole pleon, 1.2 times as long as wide.

Antennule slender, peduncle article 1 elongate, 4 times as long as wide, with 2 longer dorsal simple setae, 2 shorter inner simple setae, and 3 subdistal outer penicillate setae; article 2 0.35 times as long as article 1, distally with 3 simple setae at least as long as article and 2 outer penicillate setae; article 3 less than half length of article 2 with inner distal seta; article 4 two-thirds as long as article 3, naked. Main flagellum of 5 segments, segment 2 with 1 aesthetasc; accessory flagellum of 3 segments.

Antenna proximal article-4 naked; article 2 with simple inner seta and bearing elongate squama with 5 marginal setae; peduncle article 3 shorter than wide, with 1 inner seta; article 4 slightly longer than article 5, and 3 times as long as article 3; article 5 with paired elongate inner distal simple setae, and outer and inner distal pairs of penicillate setae. Flagellum of 5 segments.

Mouth parts. Labrum not seen. Mandible with strong, crenulated pars incisiva, small lacinia mobilis, setiferous lobe with 5 mainly bifurcate setae, pars molaris stout with denticulate distal margin; mandibular palp of 3 articles, article 1 3 times as long as wide with 6 ventral setae, distal 4 setae longer than article; article 2 slender, 1.3 times as long as article 1, with 2 parallel rows of 5 longer and 9 shorter simple setae in distal half; article 3 0.6 times as long as of article 2 with 9 inner simple setae increasing in length distally, 2 longer distal setae as long as article. Maxillule (not figured) outer endite with setose margins and 10 distal spines, inner endite with outer apophysis and 4 plumose distal spines. Maxilla with fine setae on outer margin; outer lobe of moveable endite with 2 simple setae on outer margin and 6 simple distal setae; inner lobe of movable endite with simple distal setae; outer lobe of fixed endite with 3 simple setae, 5 blunt spines (inner 3 bifurcate) and 2 subdistal finely denticulate spines; inner lobe of fixed endite with rostral row of 22 setae guarding 5 longer plumose setae. Labium not seen. Maxilliped basis naked; palp article 1 with single inner distal seta as long as article 2, and outer blunt, triangular apophysis; palp article 2 longer than wide, with 2 rows of numerous filtering setae on inner margin, 1 outer distal seta longer than article 3; palp article 3 nearly twice as long as wide, with 7 inner simple setae; palp article 4 with 9 inner and distal setae. Endite with simple distal setae, slender outer bifurcate spines and stout, spatulate, inner spines; 4 coupling hooks. Epignath large, cup-shaped, with distally setulose distal seta.

Cheliped basis twice as long as wide, dorsally naked, ventrally with midventral apophysis and 1 longer and 1 shorter distal setae; exopodite present, 3 articled, distal article with 4 to 6 marginal setae. Merus elongate, with single proximal and 2 distal ventral setae. Carpus 2.5 times as long as wide, with 2 shorter proximal and 3 longer distal simple setae along ventral margin. Chela as long as carpus; propodus wide, with 2 dorsal setae, 3 longer distal setae at insertion of dactylus, fixed finger with 3 ventral setae, 2 subdistal setae and row of 6 slender setae along cutting edge, cutting edge crenulated and armed with fine spinules and small, proximal tooth-like apophysis (stronger in male); dactylus longer than fixed finger, with fine setae but no apophyses on cutting edge, distal claw pointed.

Pereopod-1 with pronounced spine-like apophysis on coxa. Basis 4.2 times as long as wide, with 3 proximal penicillate setae on dorsal margin, ventrally subdistal and distal simple setae; exopodite present, 3-articled, article 3 with 5 distal setae. Ischium with 2 simple ventrodistal setae. Merus 0.3 times as long as basis, wider distally, with ventrodistal spine, 4 ventral setae and 1 dorsodistal simple seta. Carpus stout, nearly twice as long as merus, with 4 ventral marginal spines interspersed with simple setae, dorsally with single central and paired distal simple setae. Propodus as long as merus, ventral margin with 4 spines interspersed with simple setae, single dorsodistal spine and seta. Dactylus and unguis fused, naked, 1.4 times as long as propodus.

Pereopod-2 more slender. Basis 4.7 times as long as wide; ischium slightly longer than wide, with single dorsal and ventral setae. Merus 0.6 times as long as carpus, with 4 ventral setae and single dorsodistal seta. Carpus with 3 ventral spines in distal 0.5 interspersed with simple setae, dorsal setae as pereopod 1. Propodus as long as carpus, with 5 slender ventral spines, 3 dorsodistal setae and distal pectinate spine. Dactylus with fine distal seta, unguis slender, shorter than dactylus, the 2 together 0.7 times as long as propodus.

Pereopod 3 similar to pereopod 2.

Pereopod 4 similar to pereopod 2 but basis with midventral penicillate seta, merus proximally naked, merus half length of carpus, carpus with 8 slender ventral spines in 2 rows; propodus with dorsodistal tuft of 5 finely denticulate setae.

Pereopod 5 similar to pereopod 2 but carpus without spines.

Pereopod 6 similar to pereopod 5, but basis with dorsoproximal group of 5 penicillate setae, propodus with row of 8 ventral leaf-like spines in distal half.

Pleopods 5 pairs, all alike, but progressively smaller towards the posterior; basis attenuated, naked; slender rami each with 2 plumose distal setae, outer ramus longer and with additional single dorsal plumose seta.

Uropod biramous, both rami filiform, multi-segmented. Basis with 1 inner distal seta; exopod 0.3 times as long as endopod, with 4 segments; endopod elongate, with 15 segments.

Male. Essentially as female, small penial tubercle ventrally on pereonite 6; dimorphism of the cheliped, male cheliped being slightly more robust, with larger tooth proximal of midpoint of cutting edge of fixed finger, dactylar setal row of 9 setae.

Etymology. From the Greek – syntomos – meaning shortened, as, compared with other species in the genus, are the cheliped carpus, pereopod 1 merus and carpus, the antenna and the rostrum of the present species.

Remarks. There are 4 previously described species of Pugiodactylus , all from the general region of Australasia, P. antarcticus (Beddard, 1886) from the Antarctic at 8–232 m depth, P. agartthus Guţu and Iliffe, 1997 from Niue I., South Pacific in 2 m, P. coralensis Guţu, 1998 , from Malaysia (1–3 m depth), and P. daicovicii Guţu, 2006 , from Moreton Bay, Australia (depth not given, probably between 5 and 15 m). Unlike the present species, all the others have a conspicuous slender pointed tip to the rostrum and slender articles and squama on the antenna. Only P. agartthus has as few segments in the uropod exopod as P. syntomos sp. nov., but that species has far more segments in the antennular flagella.

Overall, and perhaps not surprisingly, P. syntomos is most similar to the other eastern Australian species, P. daicovicii (of which no description is given for the mouthparts, unfortunately), but a clear distinction, other than the robustness of the merus and carpus of pereopod 1 in the present species (merus as long as its distal width, compared with twice as long in P. daicovicii ; vide Guţu, 2006), is that P. daicovicii has no pleopods. The stout chela of P. syntomos is typical of the genus, but the cheliped carpus of this species is far shorter than those of the other species, none of which have the elongate outer distal seta on article 2 of the maxilliped palp (not known for P. daicovicii ).