Prachynella epa, Lowry & Stoddart, 2012

Lowry, J. K. & Stoddart, H. E., 2012, The Pachynidae fam. nov. (Crustacea: Amphipoda: Lysianassoidea) 3246, Zootaxa 3246 (1), pp. 1-69 : 45-46

Prachynella epa sp. nov.

( Figs 31–33 )

Type material. HOLOTYPE, female, 8.0 mm, non-ovigerous, with long setose oostegites, LACM, south-west of San Francisco , California, USA, eastern North Pacific Ocean, 37°14.03'N 123°16.84'W, 2010 m, stn EPA-102 4-6.

Type locality. South-west of San Francisco , California, USA, eastern North Pacific Ocean, 37°14.03'N 123°16.84'W, 2010 m depth .

Etymology. The specific name is taken from part of the collection station data of the type specimen; used as a noun in apposition.

Diagnostic description. Head lateral cephalic lobe large, narrowly rounded; ventral margin curved. Antenna 1 peduncular article 1 with posterodistal spine; accessory flagellum 2-articulate, article 1 short; flagellum with strong 1-field callynophore in female, [male not known]. Mandible lacinia mobilis a simple robust seta; left lamina dentata vestigial; accessory setal row absent; molar absent; palp attached midway; palp article 2 broad, longer than article 3; article 3 with both margins convex, not tapered distally. Maxilla 1 outer plate with 10 setal-teeth in 7/3 arrangement, outer row setal-teeth with medial cusps; palp vestigial, apical setae absent. Maxilliped inner plate small; outer plate large; palp 3-articulate (articles 1 and 2 fused). Gnathopod 1 chelate; ischium smaller than propodus, not swollen posteroproximally; carpus extremely compressed; propodus length about 1.6 × breadth, posterior margin well developed, palm with produced corner, pollex length about 1.2 × breadth, corner of palm with complex robust seta; dactylus reaching to corner of palm. Gnathopod 2 palm large, transverse. Pereonite 4 without dorsal spines. Pereonite 5 with 1 acute dorsal spine. Pereopod 5 merus with weak posteroproximal shoulder. Pereopod 6 basis with posteroventral lobe weakly produced; merus as broad as long, with posteroproximal shoul- der. Pereopod 7 basis subovate with posterior margin weakly dentate. Oostegites from gnathopod 2 to pereopod 5. Epimeron 3 posterior margin without projections, posteroventral corner broadly rounded. Uropod 3 biramous, inner ramus extending more than halfway along outer ramus but not reaching base of article 2. Telson as long as broad, entire, slightly emarginate.

Remarks. Prachynella epa is very similar to P. lodo and P. oculata but is easily distinguished by the large transverse palm of gnathopod 2.

Distribution. Southern California, eastern North Pacific Ocean, in 2010 m depth.

Figures

FIGURE 31. Prachynella epa sp. nov. Holotype female, 8.0 mm, LACM, southern California, USA.

FIGURE 32. Prachynella epa sp. nov. Holotype female, 8.0 mm, LACM, southern California, USA. Scales represent 0.2 mm.

FIGURE 33. Prachynella epa sp. nov. Holotype female, 8.0 mm, LACM, southern California, USA. Scales represent 0.5 mm.