Cochinorchestia poka, 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 : 173-175

Cochinorchestia poka sp. nov.

( Fig. 14 )

Orchestia sp. Ledoyer, 1979: 173, fig. 18.

Type material. Syntypes, 1 male, 8 mm, MNHN-IU-2013-11989, 1 female, 10 mm, MNHN-IU-2013-11990. Poka , Ambon Bay, Ambon, Indonesia, (~ 3°38.5'S 128°11.5'E), mangrove, coll. T. Monod, 6 January 1975.

Type locality. Poka , Ambon Bay, Ambon, Indonesia, (~ 3°38.5'S 128°11.5'E).

Etymology. Named for the type locality, Poka , Ambon Bay.

Habitat. Supralittoral, mangroves.

Description. Based on male, 8 mm ( Ledoyer, 1979: 173, fig. 18).

Head slender scales on ventroproximal surface unknown. Antenna 1 reaching slightly beyond end of antenna 2 peduncle. Antenna 2 slender, article 5 longer than article 4, flagellum virgula divina unknown.

Pereon. Gnathopod 1 sexually dimorphic; subchelate; coxa smaller than coxa 2; posterior margin of merus, carpus and propodus each with lobe covered in palmate setae, palmate lobes in both male and female; carpus longer than propodus, 1.6 × as long as propodus, 2.5 × as long as broad; propodus 'subtriangular', distally expanded with well developed posterodistal lobe, anterior margin with 2 groups of robust setae, lateral surface with 6 cuspidate setae, posterolateral surface with 4 serrate setae, palm transverse; dactylus subequal in length to palm. Gnathopod 2 sexually dimorphic; subchelate; basis slightly expanded; ischium without lobe on 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, twice as long as wide, palm extremely acute, reaching about 52% along posterior margin, smooth, with narrow distal shelf, and shallow proximal sinus, lined with robust setae (12 lateral), with small proximal sinus, posterodistal corner defined by rounded lobe, cuticular patch at corner of palm unknown; dactylus subequal in length to palm, curved, without anteroproximal bump, posterior margin smooth, not modified distally, blunt. Pereopods 3–4 unknown. Pereopod 5 propodus distinctly longer than carpus. Pereopod 7 basis posterior margin with broad, small serrations, with 1 small seta, posterodistal lobe absent; distal articles (merus and carpus) slender; merus posterior margin straight.

Pleon. Epimeron 3 posterior margin smooth, without setae, posteroventral corner with small subacute tooth, ventral margin without robust setae. Uropod 1 peduncle with 7 robust setae, distolateral robust seta present, very large (1/3 – 1/2 length of outer ramus), with simple tip; inner ramus subequal in length to outer ramus, with 1 row of 3 marginal robust setae; outer ramus with marginal robust setae, inner ramus with 3 robust setae on margins. Uropod 2 peduncle with 4 robust setae; inner ramus slightly longer than outer ramus, with 2 medial robust setae; outer ramus with 3 marginal robust setae in 1 row. Uropod 3 peduncle with 2 robust setae; ramus not fused to peduncle; ramus shorter than peduncle, 1.6 × as long as broad, triangular, without marginal robust setae, with 2 apical setae. Telson apically incised, as long as broad, with 3 apical robust setae per side.

Female (sexually dimorphic characters). Based on syntype female, 10 mm, MNHN-IU-2013-11990 ( Ledoyer, 1979: 173, fig. 18). Gnathopod 1 posterior margin of merus and carpus each with lobe covered in palmate setae; carpus 1.9 × as long as propodus, 3.1 × as long as broad; propodus subrectangular, anterior margin without robust setae, lateral surface without cuspidate setae, posterolateral surface without serrate setae, medial surface without cuspidate setae, posteromedial surface without serrate setae, posterior margin with 4 serrate setae; with 7 serrate setae, palm acute. Gnathopod 2 mitten-shaped; basis slender; posterior margin of merus, 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; propodus expanded distally, 2.8 × as long as wide, palm obtuse, smooth, nearly straight, not lined with robust setae, without cuticular patch at corner of palm.

Remarks. Cochinorchestia poka sp. nov. is similar to C. metcalfeae sp. nov. from tropical Australia. Both have gnathopod 2 with a subovate-shaped propodus with a smooth palm, however C. poka has a distal shelf on the palm (absent C. metcalfeae ) and more marginal robust setae on the rami of uropod 2.

Distribution. Indonesia. Poka , Ambon Bay, Ambon, ( Ledoyer 1979).

Figures

FIGURE 14. Cochinorchestia poka sp. nov., male, syntype, 8 mm, MNHN-IU- 2013 - 11989; female, syntype, 10 mm, MNHN- IU- 2013 - 11990; Ambon, Indonesia. Scale lines represent 0.1 mm (After Ledoyer, 1979 a: 173, fig. 18).