Pseudambasia poorei, Kilgallen, N. M. & Lowry, J. K., 2013

Kilgallen, N. M. & Lowry, J. K., 2013, The lysianassid genus Pseudambasia in Australian waters (Crustacea, Amphipoda, Lysianassidae, Lysianassinae), Zootaxa 3710 (4), pp. 301-321 : 312-313

Pseudambasia poorei sp. nov.

( Figs 9–11 )

Type material. Holotype, female with 6 embryos, 13.8 mm, NMV J46799 , NMV SA-17 from Tiparra Light, Tiparra reef, Tiparra Bay, South Australia (34º10'S, 137º23'E), sea grass Zostera and coarse rubble, 5 m, G.C.B. Poore & H.M. Lew Ton, 15 March 1985.

Type locality. Tiparra Light, Tiparra reef, Tiparra Bay, South Australia (34º10'S, 137º23'E).

Etymology. Named for the collector.

Description. Based on holotype, female, 13.8 mm, NMV J46799 . Head lateral cephalic lobe broadly rounded and slightly truncated distally; eyes oval. Antenna 1 short; peduncular article 1 short, length 1.2 × breadth, without dorsal lobe, without spines on distomedial margin; peduncular article 2 long, 0.6 × article 1; peduncular article 3 long, 0.3 × article 1; accessory flagellum short, 0.3 × primary flagellum, 2-articulate, article 1 long, 1 × article 2; primary flagellum 11-articulate, without callynophore, flagellum with aesthetascs. Antenna 2 flagellum 8- articulate. Mandible accessory setal row with 4 simple setae; molar vestigial, represented by an irregular bump; palp attached extremely proximally; article 1 extremely long, length 4.5 × breadth; article 3 slender, blade-like, with distal crease. Maxilla 1 outer plate broad, with 11 setal teeth, setal teeth of outer row with cusps in 1 row; palp 2-articulate, without apical setae; with finely setose, irregular apical margin. Maxilla 2 inner plate broad, outer plate narrower; inner plate subequal in length to outer plate. Labium outer lobe unknown. Maxilliped inner plate apical margin irregular with robust setae; outer plate small.

Gnathopod 1 simple; coxa anterior margin concave, anteroventral corner produced, rounded, coxa posterior margin slightly convex; carpus short, length 1.4 × breadth, slightly longer than (1.3 ×) propodus; propodus subtriangular, length 1.3 × breadth, palm absent. Gnathopod 2 minutely subchelate; carpus very long, length 4.3 × breadth; palm acute, with convex margin. Pereopod 5 coxa bilobate, anterior lobe strongly produced ventrally. Pereopod 6 coxa not produced; basis posterodistal corner not produced beyond ischium, ventrally truncated. Pereopod 7 basis expanded posteriorly, posterodorsally excavate, posterodistal margin oblique to very slightly concave, posterodistal corner narrowly rounded and produced halfway along merus; merus moderately expanded posteriorly.

Epimeron 3 posteroventral corner narrowly rounded/subquadrate. Uropod 1 outer ramus slightly longer than inner ramus. Uropod 2 outer ramus slightly longer than inner ramus; inner ramus without constriction. Uropod 3 peduncle short, with dorsolateral flange; rami stout, short, subequal in length. Telson as long as broad, lateral margins rounded, apical margin rounded.

Remarks. Pseudambasia poorei is unique within the genus by having a simple first gnathopod and a vestigial molar represented by an irregularly shaped lump on the mandible. The short, stout uropods of this species are also unlike its congeners which are generally long and slender. Its torpedo-like body shape is also a distinguishing characteristic.

Distribution. Tiparra Bay, South Australia.

Figures

FIGURE 9. Pseudambasia poorei sp. nov., habitus, holotype, female, NMV J 46799, 13.8 mm.

FIGURE 10. Pseudambasia poorei sp. nov., habitus, holotype, female, 13.8 mm, NMV J 46799, Tiparra Bay, South Australia. Scale bars: 0.2 mm.

FIGURE 11. Pseudambasia poorei sp. nov., habitus, holotype, female, 13.8 mm, NMV J 46799, Tiparra Bay, South Australia. Scale bars: G 1 - 2 and P 3 - 7, 0.5 mm; U 1 - 3 and T, 0.2 mm.