Pendanthura siamensis, 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 : 2090-2092

Pendanthura siamensis sp. nov.

(Figures 23, 24)

Type material. HOLOTYPE: USNM 253121 , l 3.2 mm, ®fth Thai±Danish

Expedition, 7 ss 55 ¾ 22 ² N, 98 ss 49 ¾ 45 ² E, 13±18 m, coll. Gallardo, 14 February 1966.

FIG. 23. Pendanthura siamensis sp. nov.: (A) ldorsal view; (B) lantennule; (C) lantenna; (D) mandible; (E) pleotelson; (F) uropod; (G) maxilla; (H) maxilliped; (I) pleopod 1; (J) lpleopod 2.

FIG. 24. Pendanthura siamensis sp. nov.: (A) m antennule; (B) m antenna; (C) m pereopod 1; (D) lpereopod 1; (E) pereopod 2; (F) pereopod 7.

PARATYPES: USNM 253122 , 16 , l22 ovigerous m, 20 non-ovigerous m, 12 juveniles, same data as holotype .

Other material examined. USNM 253123 , two, l one ovigerous m, two nonovigerous m, ®ve juveniles, ®fth Thai ± Danish Expedition, 6 ss 45 ¾ 00 ² N, 99 ss 32 ¾ 04 ² E, coll. Gallardo, 3 February 1966 . USNM 253124 , nine ovigerous m, ®ve non-ovigerou s m, three juveniles, ®fth Thai ± Dan Program, locality unknown, January ± March 1966 .

Diagnosis. Male: Body about 7.6 times longer than greatest width at pereonite 4. Cephalon slightly wider than midlength, with pronounced rostrum; eyes well pigmented. Telson length slightly more than twice width, posterior margin broadly rounded. Antennular peduncle of three articles, decreasing in length distally; ¯agellum of three articles, penultimate and terminal articles each bearing four aesthetascs. Antennal peduncle of ®ve articles, article 3 seven-eighths length of article 4, article 5 six-sevenths length of article 4; ¯agellum of single short setose article. Mandibular palp of single short article, with two distal setae; incisor of three cusps; lamina dentata of eight teeth; molar bluntly triangular, non-sclerotized. Maxilla with single strong spine and several more slender spines. Maxillipedal palp of single broad article, bearing ®ve distal setae; slender, thin-walled endite on mesial surface bearing single terminal seta. Pereopod 1, propodus ināted, palm faintly sinuous, bearing few well separated setae, mesial surface bearing band of short stiOE setae; unguis two-thirds length of rest of dactylus. Pereopod 2, carpus triangular, lacking free anterior margin; propodus 2.5 times longer than wide, with serrate posterodistal seta. Pereopod 7, carpus with anterior margin shorter than posterior; propodus with two posterodistal serrate setae. Pleopod 1, rami subequal in length, exopod operculiform, 2.5 times wider than endopod. Pleopod 2, exopod two-thirds length of endopod, with ®ve distal plumose setae; endopod with four distal plumose setae, copulatory stylet articulating just short of midlength of mesial margin. Uropodal exopod narrowly ovate, distally rounded, reaching base of endopod; latter ovate, distally rounded, setose.

Female: Eye as in male. Antennular ¯agellum of two articles, terminal article bearing two aesthetascs. Antenna relatively shorter than in male, with peduncle articles 4 and 5 noticeably less elongate. Pereopod 1, propodus with single row of about ten stiOE setae on mesial surface near palm.

Colour. Cephalon with irregular band of pigment between eyes; pereonites and pleon with small irregular lateral patches of pigment; telson with broad patch falling well short of posterior margin.

Remarks. Pendanthura siamensis is a much larger species than P. seminigra and lacks the latter’s distinctive pigment pattern. The arrangement of the stiOE setae on the mesial face of the propodus of pereopod 1, in both male and female, is distinctive and diOEers from the other described species.

Etymology. The speci®c name refers to Siam, the old name for Thailand.