Debroyerella similis ( Thurston, 1974 )

Lowry, J. K. & Kilgallen, N. M., 2015, Debroyerella gen. nov. and Ulladulla gen. nov., two new lysianassoid genera (Crustacea, Amphipoda, Lysianassoidea), Zootaxa 3920 (1), pp. 153-162 : 155-156

Debroyerella similis ( Thurston, 1974)

Cheirimedon fougneri .— Walker, 1907: 9.— Schellenberg, 1926: 263, fig. 13.— K.H. Barnard, 1930: 326.— Nicholls, 1938: 23 (in part).— Shoemaker, 1945: 289 (in part).

Cheirimedon similis Thurston, 1974: 54 , figs 19f–i, 20, 21.— Lowry & Bullock, 1976: 86.— Lincoln & Hurley, 1981: 108.— De Broyer, 1983: 185, figs 50–52.— Slattery & Oliver, 1986: 173.— De Broyer & Jażdżewski, 1993: 66.— Barnard & Karaman, 1991: 475.

not Cheirimedon similis .— Andres, 1983: 185. (= C. solidus ).

Types. Holotype, female, 19 mm, NHM 1972:88:l. Allotype, male, 16 mm, NHM 1972:89:1. Paratypes, NHM 1972:90:1000; NHM 1972:91:l, NHM 1972:92:1000; NHM 1907:6:6:76-81, NHM 1930:8:1:18-19.

Other paratypes are held by the British Antarctic Survey (14 specimens); the Institute of Oceanographic Sciences (6 specimens); 11 specimens ZMB 20310; 10 specimens ZMUC.

Type locality. Marguerite Bay, Stonington Island, Antarctic Peninsula.

Description. Head, lateral cephalic lobe rounded; eyes reniform. Antenna 1 peduncular article 1 without anterodistal lobe; accessory flagellum with an elongate article 1 (at least twice as long as article 2) partially covering callynophore, 6-articulate; primary flagellum with weak 1-field callynophore, or without callynophore; robust setae absent from proximal articles; calceoli absent. Antenna 2 peduncular article 3 short; articles 3 to 5 not enlarged, brush setae absent; calceoli absent. Labrum (epistome and upper lip) separate; epistome produced equally with upper lip, straight; upper lip not produced. Mandible molar an (?) asymmetrically reduced column, proximally setose, distally triturating; left lacinia mobilis a long, slender robust seta. Maxilla 1 outer plate setal-teeth in a welldeveloped 7/4 crown arrangement; palp distal margin with apical robust setae. Maxilla 2 inner plate significantly shorter than outer plate. Maxilliped outer plate with 2 long (one slender, one broad) apical robust setae.

Gnathopod 1 coxa large, about as long as coxa 2, subrectangular with straight to very slightly concave anterior margin, not expanded distally; basis sparsely setose along anterior margin; ischium short; propodus margins subparallel, palm slightly acute, entire, straight; dactylus simple. Gnathopod 2 subchelate; propodus palm transverse, straight; dactylus fitting palm. Pereopod 4 coxa with a well-developed posteroventral lobe. Pereopod 5 coxa slightly longer than broad, producing posterior lobe; basis longer than broad, posterior margin weakly serrate; carpus 2.5 × longer than wide; propodus 4 × times longer than wide. Pereopod 6 carpus 3 × longer than wide; propodus 3.5 × times longer than wide. Pereopod 7 basis posterior margin evenly rounded, posterodistally produced less than halfway along merus; carpus 2.5 × longer than wide; propodus 3 × times longer than wide.

Epimeron 3 posterior margin smooth or minutely serrate, posteroventral corner subquadrate and forming a very weak spine. Urosomite 1 not projecting over urosomite 2, with anterodorsal notch and slightly rounded boss. Uropod 2 inner ramus without constriction. Uropod 3 inner ramus slightly shorter than outer ramus, outer ramus article 2 short, with plumose setae on both rami. Telson subequal in length and width, cleft to 55% of length, with dorsal robust setae, and 1 apical robust seta on each lobe.

Depth range. 7– 385 m.

Remarks. See remarks under D. fougneri for a comparison with that species. Debroyerella similis can be distinguished from D. solidus by the shorter and more deeply cleft telson , and the narrower coxa and propodus of gnathopod 1.

Distribution. Antarctica. Gauss winter station, Davis Sea ( Schellenberg 1926); McMurdo Sound, Ross Sea ( Walker 1907); Stonington Island, Antarctic Peninsula ( Thurston 1974).