Phyllidia exquisita Brunckhorst, 1993

Yonow, Nathalie, 2012, Opisthobranchs from the western Indian Ocean, with descriptions of two new species and ten new records (Mollusca, Gastropoda), ZooKeys 197, pp. 1-130 : 46-47

Phyllidia exquisita Brunckhorst, 1993 Fig. 18, Plate 63

Phyllidia exquisita Brunckhorst, 1993: 38, pl. 3C (SW Thailand + W Pacific); Debelius and Kuiter 2007: 267 (Maldives).

Material.

Maldives: single specimen 15 mm (11 × 6 mm pres.), Dhigu Tila, near Gulhi, South Malé Atoll, 12 m depth, 14 October 1994, leg. SG Buttress & RC Anderson. - Madagascar: photo of one individual, Nosy Bé, 12-14 m depth, 25 July 2010, S Bachel (http://seaslugs.free.fr/nudibranche/a_intro.htm). - Mayotte: photo of one individual, Ilot Blanc de Mtsamboro, 4 m depth, 30 Dec 2010, M Deuss (http://seaslugs.free.fr/nudibranche/a_intro.htm).

Description.

Elongated oval animal with granular white ground colour and three black lines connected anteriorly around rhinophores but not posteriorly; central one shortest and widest. Tubercles present in black areas. Three main rows of orange-tipped tubercles in life, middle ones located along central black line, lateral ones between black lines. Several isolated orange-tipped tubercles outside black lines within marginal band of granular white, which also contains non-orange tubercles. Ring of rounded black spots at edge of granular white and bordering the orange margin. Rhinophores same orange colour as tubercles and margin; anal papilla faintly orange. When the colour images of the living specimen are magnified, a completely separate band is visible around the margin, which is translucent when not pigmented with orange (Plate 63).

The preserved specimen does not retain any orange pigmentation. The tubercles located on the black lines are clearly spiculose, while those located on white areas are covered by granular pigment (Fig. 18A). The anus is very difficult to see, located far posteriorly and not on a tubercle. Ventrally, the anterior margin of the foot appears to be concave; the oral tentacles are conical (Fig. 18B).

Distribution.

Brunckhorst (1993) described this species from one juvenile specimen (15 mm) from the eastern Indian Ocean and nine specimens (11-30 mm) from the West Pacific but it has been recorded to 45 mm in eastern Australia ( Cobb and Willan 2006). This first record from the Maldives records its distribution in the western Indian Ocean, and photographs from the Maldives and Kenya are available on NudiPixel. Phyllidia schupporum Fahrner & Schrödl (2000) was originally described from the Red Sea and compared to Phyllidia exquisita ; it is the most similar species but it has very high spiculose tubercles (see also Yonow 2008). The numerous photographs now available on the internet show that there are several similar species but, of those with three to four black lines and granular white colour pattern most similar to the holotype of Phyllidia exquisita , variations occur from no orange margin to fragmented and complete orange margins, and these can in all probability be assigned to exquisita. Until specimens of the other illustrated forms are examined, their identities must remain unconfirmed.