Ultimachelium Lowry & Stoddart 2012, gen. nov.

• Main Authors: Lowry, J. K., Stoddart, H. E.
• Format: Text
• Language: unknown
• Published: Zenodo 2012
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Malacostraca; Amphipoda; Pakynidae; Ultimachelium; Antarctic; The Antarctic; Pacific; Argentina; Argentine; Seta; Tac; Lowry; Pina; Antarc*; North Atlantic
• Online Access: https://dx.doi.org/10.5281/zenodo.5251319; https://zenodo.org/record/5251319

Ultimachelium gen. nov. Type species . Ultimachelium tac sp. nov. Etymology. The generic name is contrived. Diagnostic description. Body shape slender. Head lateral cephalic lobe large, broadly or narrowly rounded. Antenna 1 peduncular article 1 without posterodistal spine; accessory flagellum article 1 long flagellum with callynophore in female. Mandible with accessory setal row absent; left lamina dentata absent; palp attached distally; palp article 2 broad, article 3 with subparallel margins or tapered distally. Maxilla 1 outer plate setal-teeth smooth, at least one inner row setal-tooth absent; palp absent. Maxilliped inner plate absent outer plate medium size; palp 4-articulate, article 4 large. Gnathopod 1 ischium slightly smaller than, subequal to or larger than propodus; corner of palm without robust seta. Gnathopod 2 palm obtuse. Epimeron 3 posteroventral corner projecting, narrowly rounded . Uropod 3 biramous. Species composition. Ultimachelium contains four species: U. barnardi (Alonso de Pina, 1993); U. nichollsi (Lowry, 1984); U. schellenbergi (Lowry, 1984); U. tac sp. nov. Remarks. Species in Ultimachelium were previously assigned to Pachychelium . In our view the old concept of Pachychelium is a complex of three genera: Pachychelium in the North Atlantic and North Pacific with one species in the deep-water tropics of north-eastern Australia; Smaraldia , a monotypic genus currently confined to southern temperate Australia; and Ultimachelium in southern South America and the Antarctic. : Published as part of Lowry, J. K. & Stoddart, H. E., 2012, The Pachynidae fam. nov. (Crustacea: Amphipoda: Lysianassoidea) 3246, pp. 1-69 in Zootaxa 3246 (1) on page 62, DOI: 10.11646/zootaxa.3246.1.1, http://zenodo.org/record/5249007 : {"references": ["Alonso de Pina, G. (1993) Pachychelium barnardi, new species, from Argentina, and the occurrence of other lysianassids on the Argentine continental shelf (Amphipoda: Lysianassidae). Journal of Crustacean Biology, 13 (2), 377 - 382.", "Lowry, J. K. (1984) Systematics of the pachynid group of lysianassoid Amphipoda (Crustacea). Records of the Australian Museum, 36 (2), 51 - 105."]}