Malacanthura arabica, Kensley & Schotte, 2000

Kensley, B. & Schotte, M., 2000, New species and records of anthuridean isopod crustaceans from the Indian Ocean, Journal of Natural History 34, pp. 2057-2121 : 2078-2080

Malacanthura arabica sp. nov.

(Figures 15, 16)

Type material. HOLOTYPE. USNM 253268 , l 18.7 mm, sta 5S3, 26 ¾ 30 ¾ N, 50 ss 05.30 ¾ E, 1.5 m, Tarut Bay , Persian Gulf, Saudi Arabia, May 1982 . PARATYPES. USNM 253269 , one l 15.2 mm, one non-ovigerou s m 15.3 mm, sta 1S2, 25 ss 05.29 ¾ N, 50 ss 36.70 ¾ E, 7 m, Tarut Bay , Persian Gulf, Saudi Arabia, May 1982 .

Other material examined. One, l ten non-ovigerous m, 13 juveniles, from 17 stations, Tarut Bay , 1.5±7.0 m, Persian Gulf, Saudi Arabia , 1981±1982.

Diagnosis. Male: Exoskeleton moderately indurate. Telson about 2.5 times longer than basal width, dorsally strongly convex, with strong rounded middorsal longitudinal ridge, latter ¯anked by short lateral ridges in posterior half, posterior margin evenly rounded, lateral margin with pronounced`shoulder’ just beyond midlength. Antennular ¯agellum of nine articles, articles 2±8 bearing whorl of aesthtascs. Antennal ¯agellum of seven articles. Mandibular palp with terminal article bearing row of 12 stiOE setae; molar short, rounded. Maxillipedal palp of three articles, article 2 longest, with row of ten short setae on mesial margin. Pereopod 1, propodus expanded proximally, palm convex, with band of dense setae on mesial surface. Pereopod 2, carpus triangular, lacking free anterior margin; propodus linear, with several simple setae on posterior margin, short squat dentate seta posterodistally. Pereopod 7, carpus rectangular, almost three times longer than wide, with several setae and stiOE robust setae on posterior margin; propodus narrow, rectangular, about four times longer than wide, with three stout posterodistal fringed setae. Pleopod 1, endopod slightly shorter than, and about half width of exopod, with about 11 distal plumose marginal setae. Pleopod 2, slender copulatory stylet articulating at midlength of mesial margin of endopod; latter slightly longer than exopod. FIG. 15. Malacanthura arabica sp. nov. (A) ldorsal view; (B) lantennule; (C) antenna; (D) maxilla; (E) maxilliped; (F) mandibular palp; (G) mandible; (H) pleopod 1; (I) lpleopod 2; (J) uropodal protopod and endopod. K, uropodal exopod.

Uropodal exopod about three times longer than greatest width, distally strongly notched, apex narrowly rounded; endopod roughly triangular, about 1.3 times longer than basal width.

Female: Resembles male in overall proportions. Eye somewhat smaller than in male. Antennular ¯agellum of nine articles. Antennal ¯agellum of seven articles. Pereopod 1 as in male, but with fewer setae on mesial surface of propodus.

Remarks. Malacanthura arabica bears a close resemblance to M. mombasa Kensley, 1980a , from Kenya, in general appearance and in the structure of the appendages. The most easily discerned diOEerence lies in the telson: in M. mombasa a distinct shoulder is lacking, while the lateral ridges extend further anteriorly than in A. arabica . The maxilliped in the Kenyan species is proportionally squatter than in the present species.

Etymology. The speci®c names derives from the general region of the type locality, the Persian (or Arabian) Gulf.

FIG. 16. Malacanthura arabica sp. nov.: (A) m pereopod 1; (B) lpereopod 1; (C) pereopod 2; (D) pereopod 7.