Rectarcturus tuberculatus Schultz, 1981

Poore, Gary C. B., 2013, Rectarcturidae Poore, 2001 rediagnosed with descriptions of new Australian genera and species (Isopoda: Valvifera), Memoirs of Museum Victoria 70, pp. 17-36 : 26-27

Rectarcturus tuberculatus Schultz, 1981

Rectarcturus tuberculatus Schultz, 1981: 68–70 , fig. 4. – Park and Wägele 1995: 75–83, figs 13–18.

Material examined. N of South Shetland Is. , 57°09'S, 58°58'W – 58°00'S, 58°50'W, 3477–3590 m (Eltanin stn 6-363), USNM 181263 (ovigerous female, 9.5 mm) .

Description. Antennule flagellum article 1 with 3 pairs plus 1 aesthetascs, article 2 with 2 aesthetascs. Antenna, articles 1–2 short, stout, with ventrolateral flange; article 5 0.7 times length of article 4; flagellum of 3 articles, 0.7 times length of peduncle article 5.

Pereopod 1 propodus twice as long as wide. Pereopod 2 with tubercle on extensor margin of basis only; dactylus unguis 0.9 times length of dactylus body. Pereopod 4 dactylus body 0.9 times as long as propodus, unguis setiform, 0.4 times length of dactylus body. Pereopods 5–7 with 2 stout tubercles on extensor margin of basis, 1 each on carpus– propodus.

Distribution. South Atlantic. N of South Shetland Is., 57– 59°S, 3477–3590 m depth (type locality); Straits of Magellan , Argentina, 52°S, 25–41 m.

Remarks. Schultz’s (1981) illustration shows pairs of submedian tubercles and several pairs of sublateral tubercles in transverse rows across each pereonite. The pleotelson has midlength lateral marginal wings. I have re-examined his type material at the US National Museum and can add to his brief description: pereopods 2–4 with well-spaced setae as in his figure, oostegites 1–4 with coxal supports, oostegites 5 absent. The species’ type locality is at a greater depth than any other in the family, although Park and Wägele’s record was at typical depths. Subtle differences between their extensive description and detailed illustrations and those of Schultz may indicate that they had material of another species: the propodi of pereopods 1 and 2 are less elongate than in the type, and the sculpture is more complex.