Phyllidiella zeylanica (Kelaart, 1858)

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 : 868-869

Phyllidiella zeylanica (Kelaart, 1858)

(®gure 19a)

Phyllidia varicosa: Risbec, 1929: 49 , ®gures 10±16 (not ®gures 6, 7b, 8a, b as per Yonow, 1996).

Phyllidiopsis cf. striata: Edmunds, 1972: 83 (part), ®gure 3D, G (not P. rosans as per Brunckhorst, 1993).

NOT Phyllidia empelia Yonow, 1984: 223 , ®gures 6, 7B, 8A, B (as per Brunckhorst, 1993) (5 Phyllidiella striata , q.v. p. 866).

Phyllidiella zeylanica: Yonow, 1996: 502 , ®gure 10.

Material. Chag96/3: 26 mm; Salomon Channel, Salomon Atoll; 9 February 1996; at 6 m depth (no photograph). Chag96/11: 36 mm; outer reef, Ile Anglais, Salomon Atoll, 11 February 1996; at 15 m depth. Chag96/19: 24 mm; outer reef, Ile de la Passe, Salomon Atoll; 12 February 1996; at 19 m depth. Chag96/39h: 333 13 mm; Salomon Atoll; 13± 15 February 1996.

Description. All specimens have the classic hallmarks of P. zeylanica (®gure 19a): the squared appearance of the anterior end of the animal, the curled-under edges of the mantle, the few, spaced lamellae on the long rhinophores, and the rather peculiar mouth-oral tentacle arrangement; these characters remain in the preserved specimens. The faintly tuberculate areas are pink and the smooth bands black. The long rhinophores are black, tapered and bent back slightly over the dorsum.

Geographic distribution. Indian Ocean: East Africa to Christmas Island (Yonow, 1996).

Remarks. Specimen 96/11 is almost identical to Edmunds’ ®gure (1972: ®gure 3D); both are unusual in having broken longitudinal lines. Brunckhorst (1993: 56) assigned Edmunds’ specimen to Phyllidiella rosans but P. rosans bears smooth, usually continuous, pink ridges (q.v. p. 864). Furthermore, in Edmunds’ drawing of the ventral anterior end, the arrangement is the same as in the drawing of P. zeylanica (Yonow, 1996: ®gure 10C); however, Edmunds did state that the oral tentacles were grey, not black.

(a) (b)

(c) (d)