Debroyerella fougneri ( Walker, 1903 )

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 : 154-155

Debroyerella fougneri ( Walker, 1903)

Cheirimedon fougneri Walker, 1903: 41 , pl. 7, figs 1–6.— Stebbing, 1906: 720.— Nicholls, 1938: 23 (in part, part = C. similis ).— Shoemaker, 1945: 289 (in part, part = C. similis ).— J.L. Barnard, 1958: 90.— Emison, 1968: 203, fig. 10, tables 10, 12 (ecology).— J.L. Barnard, 1969: 314.— Thurston & Allen, 1969: 357.— Bellan-Santini, 1972b: 689, pls 6, 7.— Arnaud, 1974: 572, 648.— Thurston, 1974: 50, figs 17, 18, 19a–e, table 1.— Lowry & Bullock, 1976: 86.— De Broyer, 1983: 182.— Barnard & Karaman, 1991: 475.— Klages, 1991: 50.— De Broyer & Jażdżewski, 1993: 66.— Johnson et al., 2001: table 3.— La Mesa et al., 2004: 724, table 2 (ecology).— De Broyer et al. 2007: 137.

not Cheirimedon fougneri . Walker, 1907: 9.— Schellenberg, 1926: 263, fig. 13.— K.H. Barnard, 1930: 326. (= C. similis ).

Types. Syntypes, NHM 1903: 10:15: 13–15 (9 specimens in alcohol + 11 slides).

Type locality. Ross Sea (78°35'S), surface.

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, 5-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 present; 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 setalteeth in a well-developed 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 slightly concave anterior margin, slightly expanded distally; basis without setae along anterior margin; ischium short; propodus large, margins subparallel, palm slightly acute, entire, subtly sinusoidal, with small, irregular serrations; dactylus simple. Gnathopod 2 subchelate; propodus palm transverse to slightly obtuse, slightly concave; dactylus fitting palm. Pereopod 4 coxa with a well-developed posteroventral lobe. Pereopod 5 coxa about as long as broad, posterior lobe slightly produced; basis longer than broad, posterior margin weakly serrate; carpus 4 × longer than wide; propodus 5 × longer than wide. Pereopod 6 carpus 4 × longer than wide; propodus 5 × longer than wide. Pereopod 7 basis posterior margin evenly rounded, posterodistally produced less than halfway along merus; carpus 4 × longer than wide; propodus 4 × longer than wide.

Epimeron 3 posterior margin smooth or very minutely serrate distally, posteroventral corner forming small, 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 two-thirds as long as outer ramus; outer ramus article 2 short, with plumose setae on both rami. Telson distinctly longer than broad (length 1.4 × width), cleft to 35% of length, without dorsal robust setae, with 1 apical robust seta on each lobe.

Male (sexually dimorphic characters). Calceoli present on antennae 1 and 2.

Depth range. 0 m, surface ( De Broyer et al. 2007).

Remarks. The variation of character states between the three currently described species of Debroyerella gen. sp. nov. is extremely subtle, and the species are morphologically very similar. Debroyerella fougneri is distinguished from D. similis ( Thurston, 1974) by the broader and more distally expanded gnathopod 1 coxa, the shallower coxa of pereopod 5 and the longer and more weakly cleft telson . The same species can be separated from D. solidus ( Andres, 1986) by the less convex and more sinuous palm of gnathopod 1, and the longer and more slender carpus and propodus of pereopods 5–7.

Distribution. Antarctica. Adélie Coast ( Nicholls 1938); Palmer Archipelago ( Shoemaker 1945); Shackleton Glacier ( Nicholls 1938); Ross Sea ( Shoemaker 1945, La Mesa et al. 2004); Weddell Sea ( Klages 1991); Davis Sea ( Johnson et al. 2001).