Ultimachelium barnardi ( Alonso de Pina, 1993 )

Lowry, J. K. & Stoddart, H. E., 2012, The Pachynidae fam. nov. (Crustacea: Amphipoda: Lysianassoidea) 3246, Zootaxa 3246 (1), pp. 1-69 : 62-63

Ultimachelium barnardi ( Alonso de Pina, 1993)

Pachychelium barnardi Alonso de Pina, 1993: 377 , figs 1–3. ― De Broyer & Jazdzewski, 1993: 72. ― Tablado & Venerus, 2000: 219.

Ultimachelium barnardi . ― De Broyer et al., 2007: 157.

Diagnostic description. [Head shape not known]. Antenna 1 peduncular article 1 without posterodistal spine; accessory flagellum 2-articulate, article 1 long; flagellum without callynophore in specimens of unknown sex. Mandible lacinia mobilis absent; lamina dentata absent; accessory setal row absent; molar absent; palp attached distally; palp article 2 broad, as long as article 3; article 3 with subparallel margins. Maxilla 1 outer plate with 6 setal-teeth in 3/3 arrangement, setal-teeth smooth; palp absent. Maxilliped inner plate absent; outer plate medium size; palp 4-articulate, article 4 large. Gnathopod 1 subchelate; ischium subequal to propodus; merus without anterior margin; carpus extremely compressed; propodus length about 1.7 × breadth, posterior margin extremely reduced, palm with produced corner, corner of palm without robust seta; dactylus reaching to corner of palm. Gnathopod 2 palm minute, obtuse. Pereonite 4 without dorsal spines. Pereonite 5 without dorsal spines. Pereopod 5

merus without posteroproximal shoulder. Pereopod 6 basis with posteroventral lobe weakly produced; merus longer than broad, without posteroproximal shoulder. Pereopod 7 basis subrectangular, posterodistal corner subquadrate, posterior margin weakly dentate; merus, length of anterior margin 1.6 × proximal breadth. Epimeron 3 posterior margin without projections, posteroventral corner projecting, narrowly rounded. Uropod 3 biramous, inner ramus extending beyond article 1 of outer ramus. Telson slightly shorter than broad, entire.

Distribution. Southern Argentina, western South Atlantic Ocean; to 6 m depth.