Pachychelium fucaensis, Lowry & Stoddart, 2012

Lowry, J. K. & Stoddart, H. E., 2012, The Pachynidae fam. nov. (Crustacea: Amphipoda: Lysianassoidea) 3246, Zootaxa 3246 (1), pp. 1-69 : 32-34

Pachychelium fucaensis sp. nov.

( Figs 21 , 22 )

Type material. HOLOTYPE, sex not known, 2.7 mm, NMCC 1988-0047 , Clover Point , Juan de Fuca Strait, Vancouver Island, British Columbia, Canada, 48°23'01"N 123°21'46"W, 85 m, 28 August 1976, G.W. O'Connell, stn GWO W158A . PARATYPES: 1 specimen, LACM 77 - 283.2 , ridge south of Santa Rosa Island , Santa Cruz Basin, off California, U.S.A., 33°49.0'N 119°59.9'W, 103–108 m, bio-box, 1977–78, Bureau of Land Management Survey, RV Thomas G. Thompson, stn 80835 BF.5 ; 1 specimen, LACM 77 - 284.1 , south of Santa Cruz Island , Santa Cruz Basin, off California, U.S.A., 33°46.2'N 119°50.9'W, 222–271 m, bio-box, 1977–78, Bureau of Land Management Survey, RV Thomas G. Thompson, stn 80929 BF.1 .

Type locality. Clover Point , Juan de Fuca Strait, Vancouver Island, British Columbia, Canada, 48°23'01"N 123°21'46"W, 85 m depth .

Etymology. Named for the type locality, Juan de Fuca Strait.

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 with weak 1-field callynophore in specimen 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 4 setal-teeth in 4/0 or 3/1 arrangement, setal-teeth smooth; palp absent. Maxilliped inner plate absent; outer plate medium size; palp 3-articulate (article 4 absent), article 3 length 2.2 × breadth. Gnathopod 1 subchelate; ischium smaller than propodus, not swollen posteroproximally; carpus extremely compressed; propodus length about 1.8 × breadth, posterior margin extremely reduced, with produced posterodistal corner, with simple robust seta; dactylus over-reaching 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 with posterior margin smooth; merus length of anterior margin 1.7 × proximal breadth. Epimeron 3 posterior margin without projections, posteroventral corner broadly rounded. Uropod 3 biramous, inner ramus extending more than halfway along outer ramus but not reaching base of article 2. Telson as long as broad, entire.

Remarks. Pachychelium fucaensis and P. davidis both have four setal-teeth in either a 4/0 or 3/1 arrangement. However, P. fucaensis has the dactylus of gnathopod 1 over-reaching the palm (just reaching corner of palm in P. davidis ). Pachychelium fucaensis is the only species with a produced corner on the palm of gnathopod 1.

Distribution. Vancouver Island, British Columbia and southern California, eastern North Pacific Ocean; 85– 222 m depth.

Figures

FIGURE 21. Pachychelium fucaensis sp. nov. Holotype, 2.7 mm, NMCC 1988 - 0047, Clover Point, Vancouver Island, Canada. Scales represent 0.05 mm.

FIGURE 22. Pachychelium fucaensis sp. nov. Holotype, 2.7 mm, NMCC 1988 - 0047, Clover Point Vancouver Island, Canada. Scales represent 0.1 mm.