Debroyerella similis Thurston 1974

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).