Proboloides aequicornis (Stephensen, 1931)

Krapp-Schickel, Traudl, 2011, On the Austral-Antarctic stenothoids Proboloides, Metopoides, Torometopa and Scaphodactylus (Crustacea Amphipoda) Part 2: the genus Proboloides, with description of two new genera and the transfer of two nominal species to Metopoides, ZooKeys 86, pp. 11-45 : 25-26

Proboloides aequicornis (Stephensen, 1931) Figs 810

Stenothoe aequicornis Stephensen, 1931: 198, fig. 59

Material examined.

Type material of Stenothoe aequicornis ZMUC.

Redescription.

Body

smooth. Eyes rounded, small.

Length.

Male 5 mm.

Head.

Lateral cephalic lobes bluntly angular.

Antennae.

A1 subequal A2 or A1 scarcely> A2. A1 peduncle robust, art 1 length about 2-3 x the width; art 3 only 1/3 of art 1 length; acc. flag. with 2 arts, flagellum about 1,5 x length of peduncle, 12-14 arts. A2 subequal in length to A1, peduncle subequal to flagellum, peduncle robust, art 4 ≥ art 5, flagellum with 9-11 arts.

Mouthparts.

Md palp with 3 arts, art 1 and art 3 subequal, art 3 longer than 1/3 art 2, with 1 long distal seta. Mx 1 palp with 2 arts (but articulation not easy to see, cf. fig. 8, 9). Mxp IP separated, OP longer very short; dactylus as long as propodus.

Coxae.

Cx2 with rounded anterior margin, straight or even somewhat concave behind, front angle rounded without tooth; Cx3 with trapezoid-shaped margins, Cx4 not excavated, anterior and posterior margin rounded, wider than long.

Gnathopods.

Gn1, 2 propodi different in size and shape. Gn1 dactylus ordinary; propodus elongate, about 3 × as long as wide, palm well defined, much shorter than hind margin; carpus longer than propodus, triangular, nearly 3 × longer than wide, with parallel margins; merus with very long distal free margin. Gn2 length of propodus> Cx2; propodus about 3 × the size of propodus Gn1; hind margin much shorter than length of palm which has shallow incisions and crenulations, palmar corner scarcely defined by group of robust setae, no U-shaped incision. Dactylus subequal to palm. Gn2 carpus very short, cup-shaped, merus acutely lobate.

Peraeopods.

P5 dactylus> half length of slim propodus; merus posterodistal margin not reaching end of carpus length, basis rectolinear, width proximally and distally subequal, posterodistally rounded, but not lobed. P6 basis hind margin straight, merus posterodistal corner acutely lengthened and widened, reaching to end of carpus length; P7 similar to P6, but basis hind margin regularly rounded.

Epimeral plates.

Ep3 posterodistal corner acute, but rounded at the apex.

Uropods.

U3 peduncle shorter than ramus, art 1 of ramus subequal to art 2; peduncle with 3 robust setae distomarginally, ramus art 1 with 1 robust seta.

Telson.

Not reaching end of peduncle U3; less than twice as long as wide; distally pointed, marginally 3 robust setae.

Sexual differences.

Females unknown.

Distribution.

Between Faroes and Iceland, 375 m depth.