Pseudocallisoma platepistomum (Andres, 1977) Andres, 1977

Horton, Tammy & Thurston, Michael H., 2015, A revision of the genus Paracallisoma Chevreux, 1903 (Crustacea: Amphipoda: Scopelocheiridae: Paracallisominae) with a redescription of the type species of the genus Paracallisoma and the description of two new genera and two new species from the Atlantic Ocean, Zootaxa 3995 (1), pp. 91-132 : 127-128

Pseudocallisoma platepistomum (Andres, 1977) comb. nov.

Paracallisoma platepistomum Andres, 1977: 60 –64, figs 3, 4.— Andres & Lott 1977: 62.— Barnard & Karaman 1991: 511. Scopelocheirus coecus : — Shoemaker 1945: 186 (in part, part Pseudocallisoma coecum ).

Type material. Holotype— female, 28 mm, Zoological Museum Hamburg, ( K 30455 ), Meteor Station 3/24, 11 March 1966, 42°26.8’N 14°49.0’W to 42°40.9'N 14°49.2'W, Agassiz trawl, 5325 m.

Material examined. Iberian Basin. Station 7406#33, 6 October 1970, 39°49.9’ N 20°13.1’ W to 39°44.2’ N 20°20.4’ W, RMT8, 990– 1250 m, one specimen. Station 7478#1, 6 November 1970, 40°10.8’ N 19°58.9’ W to 40°04.1’ N 19°55.0’ W, RMT8, 1460– 2000 m, one specimen ( NHMUK 2015. 2865).

Nares Basin. Bermuda Oceanographic Expedition Net 1105, 25 July 1931, 32°12’ N 64°36’ W, metre net, 1463 m ( Shoemaker 1945).

Cape Verde Basin. Station 7089#5, 12 November 1969, 17°50’ N 25°29’ W, RMT8, 700– 790 m, one specimen. Station 7089#55, 22 November 1969, 17°28’ N 24°50’ W, RMT90, 2000–1300(–0), two specimens. Biscay Basin. Station 8508#3, 13 April 1974, 44°29.0’ N 12°29.9’ W to 44°21.0’ N 12°31.5’ W, RMT8, 1000– 1250 m, one specimen.

Diagnosis. Rostrum present, very short. Epistome straight with small, rounded process ventrally. Antenna 1, peduncle article 1 stout, conspicuously shorter than broad. Gnathopod 1, coxa 1 posterior margin weakly convex; dactylus, complex shrouded in setae. Gnathopod 2, oblique and palm acute, straight, bearing small, toothlike setae and lateral and medial submarginal setae. Coxa 4 posterodistal lobe large, relatively slender and narrowly rounded. Pereopod 6, basis posterior margin weakly sinuous, rounded distal lobe extending 30% along merus. Epimeron 2 and 3 weakly toothed posteroventrally. Uropod 3, outer ramus article 2 short, 0.11 x article 1. Telson, each lobe with three short submarginal setae.

Remarks. Pseudocallisoma platepistomum can be distinguished from P. coecum in the following features: antenna 1, peduncle article 1 much broader than long, length 0.65 x width (vs. nearly as broad as long, length 0.9 x width); gnathopod 1, coxa posterior margin convex (vs. concave), setation of complex dactylus only rising from distal margin of basal part (vs. hood-shaped protuberance above unguis densely setose); gnathopod 2, straight palm with small, tooth-like setae and lateral/medial submarginal setules (vs. sinuous, row of setules); coxa 4, posterodistal lobe large, narrowly rounded (vs. stout, broadly rounded); pereopod 6, basis posterior margin slightly concave (vs. straight); uropod 3, outer ramus article 2 very short, length 0.11 x article 1 (vs. 0.23 x); telson with three small robust setae laterally (vs. one basal robust seta). As both species in the genus appear to be meso- and bathypelagic, the specimen recorded from 5325 m (Andres 1977) may have been caught in midwater during deployment/recovery of the net rather than the seafloor.

Depth range. 790–2000 (5325) m ( Shoemaker 1945, Andres 1977).

Distribution. North Atlantic Ocean: Iberian Basin (Andres 1977); off Bermuda ( Shoemaker 1945), Cape Verde Basin, Biscay Basin.