Ultimachelium schellenbergi ( Lowry, 1984 )

Lowry, J. K. & Stoddart, H. E., 2012, The Pachynidae fam. nov. (Crustacea: Amphipoda: Lysianassoidea) 3246, Zootaxa 3246 (1), pp. 1-69: 64-65

publication ID

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

persistent identifier

http://treatment.plazi.org/id/456087D3-361A-FFC9-B8DF-0DFAFDD948ED

treatment provided by

Felipe

scientific name

Ultimachelium schellenbergi ( Lowry, 1984 )
status

 

Ultimachelium schellenbergi ( Lowry, 1984)  

( Fig. 46 View FIGURE 46 )

Pachychelium antarcticum   . ―Schellenberg, 1931: 19, fig. 8. ― Lowry & Bullock, 1976: 101 (in part).

? Pachychelium davidis   . ―K.H. Barnard, 1932: 75, fig. 32.

Pachychelium schellenbergi Lowry, 1984: 102   , figs 39–41. ― Barnard & Karaman, 1991:550. ― Gonzalez, 1991: 59. ― De Broyer & Jazdzewski, 1993: 74.

Ultimachelium schellenbergi   . ― De Broyer et al., 2007: 158.

Material examined. One specimen,?male, 4.8 mm, SMNH no. 116349, Estero Huito, north of Punta Yahuecha , northern part of Golfo de Ancud, Chile, eastern South Pacific Ocean, 41°45'30"S 73°07'50"W, 35 m, dead algae, dredge or trawl, 15 December 1948, Lund University Chile Expedition, stn M18 GoogleMaps   .

Diagnostic description. Head lateral cephalic lobe large, narrowly rounded; ventral margin curved. Antenna 1 peduncular article 1 without posterodistal spine; accessory flagellum 2-articulate, article 1 long; flagellum without callynophore in female. 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 5 or 6 setal-teeth in 3/2 or 4/2 arrangement, setal-teeth smooth; palp absent. Maxilliped inner plate absent; outer plate medium size; palp 4-articulate, article 4 large. Gnathopod 1 subchelate; ischium larger than propodus; merus without anterior margin; carpus extremely compressed; propodus length about 1.8 × breadth, posterior margin absent, 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 as broad as long, without posteroproximal shoulder. Pereopod 7 basis subovate, posterodistal corner rounded, posterior margin weakly dentate; merus, length of anterior margin 1.9 × proximal breadth. Epimeron 3 posterior margin without projections, posteroventral corner subquadrate. Uropod 3 biramous, inner ramus just reaching base of article 2 of outer ramus. Telson   as long as broad, entire.

Remarks. Ultimachelium schellenbergi   is a south-western South American species closely related to U. tac   . The main difference between these species is the size of the ischium of gnathopod 1, which is larger than the propodus in U. schellenbergi   and about the same size as the propodus in U. tac   . Ultimachelium schellenbergi   is a larger species (about 6 mm) known from shallower water (less than 35 m) than U. tac   which is about 3 mm in length and known from depths of 250 to 300 m. Unlike U. schellenbergi   , U. tac   does not have any slender setae along the anterior margins of pereopods 5 to 7.

Distribution. Southern Chile, eastern South Pacific Ocean; Magellanic area; South Georgia and Falkland Islands, Southern Ocean; 1–35 m depth.

SMNH

Department of Paleozoology, Swedish Museum of Natural History

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Amphipoda

Family

Pakynidae

Genus

Ultimachelium

Loc

Ultimachelium schellenbergi ( Lowry, 1984 )

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

Ultimachelium schellenbergi

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

Pachychelium schellenbergi

De Broyer, C. & Jazdzewski, K. 1993: 74
Barnard, J. L. & Karaman, G. S. 1991: 550
Gonzalez, E. 1991: 59
Lowry, J. K. 1984: 102
1984
Loc

Pachychelium antarcticum

Lowry, J. K. & Bullock, S. 1976: 101
1976
Loc

Pachychelium davidis

Barnard, K. H. 1932: 75
1932