Talorchestia dampieri, Lowry, J. K. & Springthorpe, R. T., 2015

Lowry, J. K. & Springthorpe, R. T., 2015, Coastal Talitridae (Amphipoda: Talitroidea) from north-western Australia to Darwin with a revision of the genus Cochinorchestia Lowry & Peart, 2010, Zootaxa 3985 (2), pp. 151-202 : 185-190

Talorchestia dampieri sp. nov.

( Figs 22–25 )

Type material. Holotype, male, 12.9 mm, AM P.97471, Mission Beach, Cygnet Bay, King Sound, Western Australia (16°27.168'S 123°0.596'E), intertidal wrack, coll. J.K. Lowry, 26 May 2010, station MIWA 1157. Paratype: female, AM P.97472, same locality.

Additional material examined. 29 specimens, AM P.84231, Mission Beach, Cape Leveque, Cygnet Bay, Western Australia (16°27.168'S 123°0.596'E), supralittoral wrack, mangrove leaves, coll. J.K. Lowry, 23 May 2010, station MIWA 1108. 16 specimens, AM P.84960, near Divers’s Lodge residence, Cygnet Bay, Cape Leveque, Western Australia (16°27.467'S 123°0.033'E), intertidal wrack, mangrove sticks and mud at edge of mangrove stand, coll. J.K. Lowry, 22 May 2010, station MIWA 1075. 44 specimens, AM P.84961, boat ramp, Catalina Place, Roebuck Bay , Western Australia (17°58.15'S 122°14.233'E), intertidal wrack, mangrove sticks and mud at edge of mangrove stand, coll. J.K. Lowry, K. Attwood, L. Hughes, M.E. Stuckey, 19 May 2010, MIWA 1073. 60 specimens, AM P.84963, Mission Beach, Cygnet Bay, Cape Leveque, Western Australia (16°27.168'S 123°0.596'E), supralittoral wrack, mangrove leaves, coll. J.K. Lowry, 23 May 2010, station MIWA 1108. 102 specimens AM P.84964, Mission Beach, Cygnet Bay, Cape Leveque, Western Australia (16°27.168'S 123°0.596'E), intertidal wrack, coll. J.K. Lowry, 26 May 2010, MIWA 1057.

Type locality. Mission Beach, Cygnet Bay, Cape Leveque, Western Australia (16°27.168'S 123°0.596'E).

Habitat. Beach-hoppers, living at the back of mangroves under leaves and woody debris.

Etymology. Named for William Dampier, a great scientist, a great navigator and the first Englishman to set foot on Australian soil at King Sound, northern Western Australia, in 1688.

Description. Based on holotype, male, 12.9 mm, AM P.97471.

Head with 5 groups of long slender scales on ventroproximal surface. Antenna 1 short, reaching less than halfway along article 4 of antenna 2 peduncle. Antenna 2 more than half body length; peduncular articles slender, article 5 longer than article 4, peduncular articles with many small robust setae; final flagellar article large, coneshaped, forming virgula divina. Upper lip without robust setae; epistome with many pores; with apical setal fringe. Mandible left lacinia mobilis 6-cuspidate (sixth minute). Maxilla 1 with small palp, 2-articulate. Maxilliped palp article 2 distomedial lobe well developed; article 4 fused with article 3.

Pereon. Gnathopod 1 sexually dimorphic; parachelate; coxa smaller than coxa 2; posterior margin of carpus and propodus each with lobe covered in palmate setae, palmate lobes in male only; carpus longer than propodus, 2.1 × as long as propodus, 2.7 × as long as broad; propodus subrectangular, anterior margin with 5 groups of robust setae; palm transverse, without spine patch on posterodistal corner; dactylus longer than palm, simplidactylate, with anterodistal denticular patch. Gnathopod 2 sexually dimorphic; subchelate; basis anterior margin smooth, slender; ischium with rounded lobe on mid-anterior margin, without anterodistal lobe on medial surface; carpus triangular, reduced (enclosed by merus and propodus), posterior lobe absent, not projecting between merus and propodus; propodus subovate, 1.7 × as long as wide, palm acute, reaching about 56% along posterior margin, smooth, without protuberance or shelf near dactylar hinge, lined with robust setae (8 medial, 8 lateral), posteromedial surface of propodus with groove, without cuticular patch at corner of palm; dactylus subequal in length to palm, sinusoidal, without anteroproximal bump, posterior margin with minute cuticular surface, not modified distally, blunt. Pereopods 2–4 coxae as wide as deep. Pereopods 3–7 cuspidactylate; dactyli without anterodistal denticular patch. Pereopod 4 significantly shorter than pereopod 3; carpus significantly shorter than carpus of pereopod 3; dactylus thickened proximally with notch midway along posterior margin and small cuticular dome at juncture with unguis. Pereopod 5 propodus distinctly longer than carpus. Pereopods 6–7 not sexually dimorphic. Pereopod 6 shorter than pereopod 7; coxa posterior lobe inner view posteroventral corner rounded, posterior margin oblique to ventral margin, posterior lobe with ridge, posterior lobe with 5 or more marginal setae. Pereopod 7 basis lateral sulcus present, very pronounced, posterodistal lobe absent; distal articles (merus and carpus) slender; merus posterior margin evenly rounded.

Pleon. Pleopods 1–3 all well developed, biramous. Epimeron 2 subequal in length to epimeron 3. Epimeron 3 posterior margin minutely serrate, with setae (tiny, about 5), posteroventral corner with small subacute tooth, ventral margin without robust setae. Uropod 1 peduncle with 19 robust setae, distolateral robust seta present, small (less than 1/4 length of outer ramus), with simple tip; inner ramus subequal in length to outer ramus, inner ramus with 12 marginal robust setae in 2 rows); outer ramus without marginal robust setae. Uropod 2 peduncle with 13 robust setae; inner ramus subequal in length to outer ramus, with 7 lateral robust in 2 rows; outer ramus with 2 marginal robust setae in 1 row. Uropod 3 peduncle with 9 robust setae; ramus not fused to peduncle, subequal in length to peduncle, 2.7 × as long as broad, linear (tapering distally), with 2 marginal robust setae, with more than 5 apical setae. Telson longer than broad, apically incised, dorsal midline entire, with 8–10 marginal and apical robust setae per lobe.

Female (sexually dimorphic characters). Based on female, paratype, AM P.97472. Gnathopod 1 simple; posterior margin of merus, carpus and propodus each without lobe covered in palmate setae; propodus anterior margin with 4 groups of robust setae. Gnathopod 2 mitten-shaped; basis expanded anteromedially; ischium without lobe on anterior margin; posterior margin of carpus and propodus each with lobe covered in palmate setae; carpus well developed (not enclosed by merus and propodus), posterior lobe present, projecting between merus and propodus; palm obtuse, nearly straight; dactylus curved, posterior margin smooth, not reaching end of palm. Oostegites long (length greater than 2 × width), longer than wide, weakly setose, setae with simple smooth tips.

Remarks. The propodus of male gnathopod 2 is very similar to T. brucei , but the uropod 3 peduncle (9 setae in T. dampieri and 2 in T. brucei ) and telson (8–10 setae in T. dampieri and 6 in T. brucei ) both have significantly more setae. Talorchestia dampieri differs from all other species in the uropod 3 ramus which is long, subequal in length to the peduncle (shorter than the peduncle in other species.)

Distribution. Australia. Roebuck Bay to King Sound, Western Australia (this study).

Figures

FIGURE 22. Talorchestia dampieri sp. nov., male, holotype, 12.9 mm, AM P. 97471, Cygnet Bay, Western Australia. Scale lines represent 0.1 mm.

FIGURE 23. Talorchestia dampieri sp. nov., male, holotype, 12.9 mm, AM P. 97471; female, paratype, AM P. 97472; Cygnet Bay, Western Australia. Scale line for male G 2 represents 1.0 mm, remainder represent 0.5 mm.

FIGURE 24. Talorchestia dampieri sp. nov., male, holotype, 12.9 mm, AM P. 97471, Cygnet Bay, Western Australia. Scale lines for U 2, lateral U 3 / T represent 0.2 mm, remainder represent 0.5 mm.

FIGURE 25. Talorchestia dampieri sp. nov., male, holotype, 12.9 mm, AM P. 97471, Cygnet Bay, Western Australia. Scale lines represent 0.5 mm.