Hypselodoris nigrostriata, (Eliot, 1904)

Yonow, Nathalie, Anderson, R. Charles & Buttress, Susan G., 2002, Opisthobranch molluscs from the Chagos Archipelago, Central Indian Ocean, Journal of Natural History 36 (7), pp. 831-882 : 858-859

Hypselodori s nigrostriata (Eliot, 1904)

(®gures 13f, 14)

Chromodoris nigrostriata Eliot, 1904a: 394 (part), pl. 24, ®gures 5, 6.

Chromodoris tenuilinearis Farran, 1905: 342 , pl. 3, ®gures 11±15; VayssieÁre, 1912: 51, pl. 1, ®gure 13, pl. 3, ®gures 39±42.

Hypselodoris nigrostriata: Rudman, 1977: 364 , pl. 1f, ®gures 1, 2, 11E.

Material. Chag96/58a, b, c: 24 mm (15 mm preserved), 27 mm (17 mm preserved), 29 mm (20 mm preserved; radular preparation); underside of coral bommie, east of Ile Poule, inside Peros Banhos Atoll; 23 February 1996; at 7 m depth. Two other individuals at same location not collected.

Description. Body smooth, robust and richly coloured: yellow with numerous black lines overlaid with purple (®gure 13f). These purple and black lines covered the dorsal surface and sides of the foot, but did not include the mantle edge, which was plain yellow. Foot with pale purple marginal band. Rhinophores and gills brilliant orange-crimson. The radula had more than 70 rows of teeth with at least 65 teeth per row. The ®rst lateral is tricuspid while the rest are bi®d but not denticulate (®gure 14).

Geographic distribution. Western Indian Ocean: Tanzania ( Eliot, 1904a; Rudman, 1977) and Gulf of Aden (VayssieÁre, 1912) to Sri Lanka ( Farran, 1905).

Remarks. The three specimens are similar in colour pattern to the original description from Zanzibar ( Eliot, 1904a) and those redescribed from Tanzania (Rudman, 1977). Rudman’s specimens diOEered slightly in having orange and white gills instead of uniformly deep orange as in these specimens. The teeth of the Chagos specimen conform with those ®gured by Rudman (1977), except that the base is much larger, as ®gured by Farran (1905), especially in the outermost teeth. The specimens were found together on a spiculose sponge covered in small tubeworms on the underside of a coral bommie (sample collected but unidenti®ed).

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