Podosirus vaderi, Bellan-Santini, 2007

Bellan-Santini, Denise, 2007, New amphipods of hydrothermal vent environments on the Mid-Atlantic Ridge, Azores Triple junction zone, Journal of Natural History 41 (9 - 12), pp. 567-596 : 572

Podosirus vaderi n. sp.

( Figures 1 , 2 )

Type locality. Mid-Atlantic Ridge, 37 ° 17.398 9 N, 32 ° 16.642 9 W, Lucky Strike site, 1680 m.

Material examined. SEAHMA 1, PL 187-09 , 12 August 2002, slurp gun 5, Lucky Strike site, 1680 m, 4 specimens: 1 female with oostegites, holotype MNHN Am-7463; 3 exemplaries of 6, 4 and 4 mm, paratypes MNHN Am-7464 .

Description. Holotype female 5 mm, with oostegites. Body slender, compressed, last segment of mesosome with a small dorsal process. Segments 1–3 of metasome with a small dorsal process. Segments of urosome each one with a dorsal process small and triangular. Rostrum moderate, lateral cephalic lobe ordinary. Eyes not visible. Antennae flagellum broken. Antenna 1, peduncle articles 1 and 2 of equal length; article 1 with a long dorsodistal process, article 3 small, primary flagellum more than 13-articulate, accessory flagellum absent. Antenna 2 slender, articles 4 and 5 equal, flagellum more than 10- articulate. Labrum entire, rounded.

Mandible with normal triturative molar, incisor sharply dentate, palp long, article 1 short, articles 2 and 3 equal in length, article 3 fringed with small spines on the distal half of the inner side, long sub-terminal spine. Maxilla 1 inner plate small with two small terminal spines, outer plate with seven broad spines. Maxilla 2 inner plate shorter than outer, eight terminal and sub-terminal setae, outer plate with nine terminal setae. Maxilliped inner plate short with two terminal triangular spines and two or three setae, outer plate with small facial spines, two terminal setae, palp with four articles, second longer than 1 and 3, article 4 longer than 3 and smooth.

Coxae 1–4 small, anteriorly produced as a sharp process. Gnathopod 1 smaller than gnathopod 2, subchelate, basis long, ischium and merus short, carpus as long as propodus, fringed with setae, propodus ovate, palmar fringed with small spines and defined by a larger spine, dactylus half of propodus. Gnathopod 2 large, basis long with two anterior crests ending distally with a small rounded process, ischium crested, merus produced, carpus triangular, propodus longer than broad, palm indented in a finger shape, proximal part with small spines and defined by three larger spines, dactylus long as two-thirds of the propodus.

Pereopods 3 and 4 similar, basis straight and long, ischium short, merus long as basis, fringed on both sides by small spines, carpus shorter than merus and propodus, propodus curved and humped in the proximal part, dactylus half length of propodus, claw-shaped.

Pereopods 5–7 similar, basis not lobate but little more broad than pereopods 3 and 4, other articles similar to pereopods 3 and 4.

Epimeral plates 1–3 similar, rounded.

Uropod 1, peduncle equal to sub-equal rami, each ramus fringed with scarce small spines. Uropod 2, outer ramus scarcely shorter than inner. Uropod 3 not expanded beyond uropods 1 and 2, rami lanceolate equal to peduncle, peduncle fringed with small spines. Telson entire, ovate, two pairs of sub-terminal spinules.

Etymology. The species is named in honour of Wim Vader for his important and friendly contribution to ‘‘amphipodology’’.

Figures

Figure 1. Map of the different hydrothermal sites.

Figure 2. Podosirus vaderi, SEAHMA 1 PIL 187-09, holotype female. (1) habitus; (2) antenna 1; (3) antenna 2; (4) mandible; (5) maxilla 1; (6) maxilla 2; (7) maxilliped; (8)uropod 1; (9) uropod 2; (10) uropod 3; (11) telson. Scale bar 100 Mm.