Ultimachelium nichollsi

• Main Authors: Lowry, J. K., Stoddart, H. E.
• Format: Text
• Language: unknown
• Published: Zenodo 2012
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Malacostraca; Amphipoda; Pakynidae; Ultimachelium; Ultimachelium nichollsi; Antarctic; Southern Ocean; New Zealand; Seta; Lowry; Antarc*; Antarctica; Antarctique*
• Online Access: https://dx.doi.org/10.5281/zenodo.5251330; https://zenodo.org/record/5251330

Ultimachelium nichollsi (Lowry, 1984) (Figs 44, 45) Pachychelium antarcticum . ― Nicholls, 1938: 14, fig. 3. ― Bellan-Santini, 1972: 215, pl. 28. ― Lowry & Bullock, 1976: 101 (in part). ― Lowry, 1982: 320. Pachychelium nichollsi Lowry, 1984: 103. ― Barnard & Karaman, 1991: 510. ― De Broyer & Jazdzewski, 1993: 72. Ultimachelium nichollsi . ― De Broyer et al ., 2007: 158. Material examined. One?female, 12 mm, USNM 1156710, off South Georgia, Southern Ocean, 54°51'S 35°03'W, 168–173 m, trawl, 10 December 1986, Professor Siedlecki , USARP cruise 601, stn 74. –1?male, 10.0 mm, USNM 1157037, unknown locality, stn AH 4-30. –1?male, 11.5 mm, USNM 1157039, unknown locality, stn AH 4-40. Diagnostic description. Head lateral cephalic lobe large, narrowly rounded; ventral margin subsigmoidal. Antenna 1 peduncular article 1 without posterodistal spine; accessory flagellum 2-articulate, article 1 long; flagellum with strong 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 tapered distally. 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 smaller than propodus merus with anterior margin carpus extremely compressed; propodus length about 1.9 × breadth, posterior margin extremely reduced, 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 2.6 × proximal breadth . Epimeron 3 posterior margin without projections, posteroventral corner subacute. Uropod 3 biramous, inner ramus just reaching base of article 2 or extending beyond article 1 of outer ramus. Telson slightly shorter than broad, entire. Remarks. Ultimachelium barnardi and U. nichollsi both have six setal-teeth on the outer plate of maxilla 1 in a 3/3 arrangement. They differ in the shape of mandibular palp article 3 (subparallel sides in U. barnardi , tapering distally in U. nichollsi ); and gnathopod 1 ischium (swollen posteroproximally in U. nichollsi , not swollen in U. barnardi ). Distribution. South Georgia, Southern Ocean and Adelie Coast, Antarctica; 46–732 m depth. : 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 63, DOI: 10.11646/zootaxa.3246.1.1, http://zenodo.org/record/5249007 : {"references": ["Lowry, J. K. (1984) Systematics of the pachynid group of lysianassoid Amphipoda (Crustacea). Records of the Australian Museum, 36 (2), 51 - 105.", "Nicholls, G. E. (1938) Amphipoda, Gammaridea. Australasian Antarctic Expedition 1911 - 14. Scientific Reports, Series C, 2 (4), 1 - 145.", "Bellan-Santini, D. (1972) Invertebres marins des XIIeme et XVeme expeditions antarctiques Francaises en Terre Adelie. 10. - Amphipodes gammariens. Tethys Supplement, 4, 157 - 238.", "Lowry, J. K. & Bullock, S. (1976) Catalogue of the marine gammaridean Amphipoda of the Southern Ocean. Bulletin of the Royal Society of New Zealand, 16, 1 - 187.", "Lowry, J. K. (1982) The status of the gammaridean Amphipoda collected by the Australasian Antarctic Expedition 1911 - 1914. Crustaceana, 42 (3), 319 - 320.", "Barnard, J. L. & Karaman, G. S. (1991) The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Records of the Australian Museum, Supplement, 13 (2), 419 - 866.", "De Broyer, C. & Jazdzewski, K. (1993) Contribution to the marine biodiversity inventory. A checklist of the Amphipoda (Crustacea) of the Southern Ocean. Documents de Travail de l'Institut Royal des Sciences Naturelles de Belgique, 73, 1 - 154.", "De Broyer, C., Lowry, J. K., Jazdzewski, K. & Robert, H. (2007) Catalogue of the Gammaridean and Corophiidean Amphipoda (Crustacea) of the Southern Ocean with distribution and ecological data. In: C. De Broyer (ed.) Census of Antarctic Marine Life: Synopsis of the Amphipoda of the Southern Ocean. Volume 1. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Biologie, 77, Supplement 1 (1), 1 - 325."]}