“Malacanthura antarctica, new species
FIGURES 6, 7
MATERIAL.-Holotype: USNM 185000, Sta WHOI Rankin 0006, 1 non-ovig. Y, 27.6 mm. Paratypes: USNM 185001, Sta WHOI Rankin 0004, 1 non-ovig. Y, 17.0 mm; USNM 185002, Sta WHOI Rankin 0011, 1 non-ovig. ?, 25.0 mm.
DESCRIPTION.-Non-ovigerous Female: Integument indurate, with numerous small scattered pits on cephalon, antennal bases, dorsal and ventral pereon, pleon, pereopod 1, pleopod 1 exopod, uropod, and telson. Body proportions: C < 1 = 2 = 3 < 4 < 5 > 6 > 7. Cephalon with low rounded rostrum. Eyes weakly pigmented, ocelli not demarked. Pereonites 4-6 each with elongate middorsal pit. Pleonites 1-5 fused, lines of fusion marked by short epimera and shallow grooves. Pleonite 6 free, lacking free lateral margins. Tel-son with 2 basal statocysts; widest in distal half, apex broadly rounded; with rounded middorsal and submedian longitudinal ridges.
Antennule with basal segment broader and longer than 2 distal peduncle segments; flagellum of four articles, three distal articles tiny, setose, with two aesthetascs. Antenna with second peduncle segment grooved to accommodate antennule, dorsal flange of groove pitted; third segment with low tubercle-bearing crest; flagellum of five setose articles. Mandibular palp 3-segmented, terminal segment half length of segment 2, with six distal setae; incisor of single stout sclerotised cusp; lamina dentata with marginal serrations faint; molar low, rounded, non-sclerotised. Maxilla with six distal spines. Maxilliped 5-segmented, segment 2 longer than three distal segments together; terminal segment set obliquely on outer distal angle of segment 4, bearing five setae. Pereopod 1 robust; propodus expanded; outer surface of propodus, merus, ischium, and basis pitted; unguis one-third length of dactylus; propodal palm with low, rounded, proximal lobe, inner palmar surface with numerous setae; carpus narrowly triangular, distally setose. Pereopod 2 much less robust than pereopod 1, propodus rectangular-linear; carpus triangular. Pereopods 4-7, propodi and carpi rectangular-linear. Pleopod 1 exopod operculiform, indurate, pitted; endopod about one-third width and three-quarters length of exopod. Uropodal basis triquetrous, ventral surface pitted; endopod ovate, not reaching telsonic apex; exopod just reaching endopod base, outer margin sinuous, apex narrowly rounded.
REMARKS.—This is the first species of Malacanthura recorded from the Antarctic. Of the six southern African species, M. coronicauda (Barnard) and M foveolata (Barnard) have tricarinate telsons, but neither is as pitted as M antarctica. M caribbica Paul and Menzies, and M mombasa Kensley both have unpitted integuments.
ETYMOLOGY.—The species was collected in the Weddell Sea, off the Antarctic continent, hence the specific name.” (Kensley, 1982)
