Phyllidia varicosa Lamarck, 1801

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 : 863

Phyllidia varicosa Lamarck, 1801

Phyllidia varicosa Lamarck : Eliot 1910: 435.

Phyllidia arabica Ehrenberg : Yonow, 1996: 495, ®gures 7, 8.

Material. Chag96/17: 8 mm; outer reef, Ile de la Passe, Salomon Atoll; 12 February 1996; at 20 m depth. Chag96/33: 80 mm; outer reef, Ile de la Passe, Salomon Atoll; 14 February 1996; at 8 m depth. Chag96/41a, b: 55 mm, 30 mm; inner reef, Ile Boddam, Salomon Atoll; 18 February 1996; at 11±13 m depth; smaller specimen coll. G. Heiss.

Description. Body black, with three raised light blue-grey ridges which were topped with deep yellow tubercles. Numerous short peripheral tuberculate ridges perpendicular to margin. Digitiform rhinophores deep yellow. Sole of foot grey with broken black line medially in all specimens.

Geographic distribution. Indo-West Paci®c: from the Red Sea and South Africa to Hawaii (Yonow, 1996).

Remarks. Previously collected from the Chagos by Gardiner and reported by Eliot (1910), Yonow (1996) noted that the specimen was collected at`Solomon Is., Indian Ocean’ but this was in error for Salomon Atoll, Chagos. There has been some controversy regarding the validity of this name for this species (Yonow, 1986; Brunckhorst, 1993; Yonow, 1996), in particular the apparent absence of a black line on the ®gure of the sole of the holotype of P. varicosa , long thought lost, and its presence in P. arabica Ehrenberg and all subsequent descriptions. The recent rediscovery of the holotype of P. varicosa in the MNHN (Paris; no registration number) and the con®rmation that it does have a black line on the sole now resolves this issue (Willan et al., 1998).