Ultimachelium nichollsi ( Lowry, 1984 )

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

publication ID

http://doi.org/ 10.11646/zootaxa.3246.1.1

DOI

http://doi.org/10.5281/zenodo.5251330

persistent identifier

http://treatment.plazi.org/id/456087D3-361B-FFB7-B8DF-0880FB634892

treatment provided by

Felipe

scientific name

Ultimachelium nichollsi ( Lowry, 1984 )
status

 

Ultimachelium nichollsi ( Lowry, 1984)  

( Figs 44 View FIGURE 44 , 45 View FIGURE 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 View Materials , 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 View Materials , unknown locality, stn AH 4-30. –1?male, 11.5 mm, USNM 1157039 View Materials , unknown locality, stn AH 4-40 GoogleMaps   .

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.

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Amphipoda

Family

Pakynidae

Genus

Ultimachelium

Loc

Ultimachelium nichollsi ( Lowry, 1984 )

Lowry, J. K. & Stoddart, H. E. 2012
2012
Loc

Ultimachelium nichollsi

De Broyer, C. & Lowry, J. K. & Jazdzewski, K. & Robert, H. 2007: 158
2007
Loc

Pachychelium nichollsi

De Broyer, C. & Jazdzewski, K. 1993: 72
Barnard, J. L. & Karaman, G. S. 1991: 510
Lowry, J. K. 1984: 103
1984
Loc

Pachychelium antarcticum

Lowry, J. K. 1982: 320
Lowry, J. K. & Bullock, S. 1976: 101
Bellan-Santini, D. 1972: 215
Nicholls, G. E. 1938: 14
1938