Pseudambasia springthorpei, 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 : 318-321

Pseudambasia springthorpei sp. nov.

( Figs 14 , 15 )

Type material. Holotype, female, 2.7 mm, AM P.68869, off jetty at Green Island, Rottnest Island, Western Australia (32°1'S 115°30'E), 1 m, brown alga on jetty pilings, R.T. Springthorpe, 21 December 1983. Paratype, male, 2.6 mm, AM P.68870, same locality information except mixed algal turf on rock.

Type locality. Off jetty at Green Island, Rottnest Island, Western Australia (32°1'S 115°30'E).

Etymology. Named for the collector.

Diagnostic description. Based on holotype female, 2.7 mm, AM P.68869. Head lateral cephalic lobe broadly rounded; eyes oval. Antenna 1 short to medium length; peduncular article 1 short, length 1.25 × breadth, without dorsal lobe; peduncular article 2 short, 0.4 × article 1; peduncular article 3 short, 0.22 × article 1; accessory flagellum short, 0.25 × primary flagellum, 2-articulate, article 1 short; primary flagellum 9-articulate, with weak 1- field callynophore, flagellum with aesthetascs. Antenna 2 flagellum 6-articulate. Mandible accessory setal row with 4 simple setae; molar reduced, represented by finely setose triangular flap; palp attached very slightly proximally; article 1 long, length 2.2 × 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, with robust setae on the apical margin. Maxilla 2 inner and outer plates broad; inner plate length 0.7 × outer plate. Labium outer lobe unknown. Maxilliped outer plate medium size, submarginal setae absent.

Gnathopod 1 weakly subchelate; coxa anterior margin straight, anteroventral corner narrowly rounded, posterior margin slightly concave; carpus short, length 1.5 × breadth, shorter than (0.8 x) propodus; propodus subtriangular, length 2 × breadth, palm extremely acute, margin slightly concave. Gnathopod 2 minutely subchelate; carpus long, length 3 × breadth; palm transverse, with convex margin. Pereopod 5 coxa equilobate. Pereopod 6 coxa not lobate posteriorly; basis posterodistal corner produced beyond ischium, forming rounded lobe. Pereopod 7 basis expanded posteriorly, posterodistal margin rounded, posterodistal corner strongly produced, forming a large, broad lobe produced more than 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 long, without dorsolateral flange; rami slender, subequal in length. Telson longer than broad, length 1.4 × breadth, lateral margins converging distally, apical margin subacute.

Remarks. Pseudambasia springthorpei is very similar to P. kalaupapa from Hawaii. They both have the mandibular palp attached slightly proximally, both have an apical robust seta on the margin of the maxilla 1 palp. They have very similar male first gnathopods sixth and seventh pereopods. The male first antenna has a weak callynophore (not present in P. kalaupapa ), the rami of uropod 3 are subequal in length (outer longer than inner in P. kalaupapa ), and the telson of P. springthorpei is apically subacute.

Distribution. Rottnest Island, Western Australia.

Figures

FIGURE 14. Pseudambasia springthorpei sp. nov., paratype, male, 2.6 mm, AM P. 68870, Green Island, Rottnest Island, Western Australia. Scale bars: 0.1 mm.

FIGURE 15. Pseudambasia springthorpei sp. nov., paratype, male, 2.6 mm, AM P. 68870, Green Island, Rottnest Island, Western Australia. Scale bars: G 1 - 2 and P 3 - 7, 0.2 mm; U 1 - 3 and T, 0.1 mm.