Phyllidiella striata (Bergh, 1889)

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 : 54-56

Phyllidiella striata (Bergh, 1889) Fig. 24, Plate 71

Phyllidiopsis striata Bergh, 1889: 866, pl. 84 figs. 23, 24 (SW Thailand); Eliot 1906a: 563 (Maldives).

Phyllidia nobilis . - Edmunds 1972: 79 (part), fig. 3A, F (Seychelles) (non Phyllidiella nobilis Bergh).

Phyllidia empelia Yonow, 1984: 223, figs. 6, 7B, 8A, B (Sri Lanka).

Phyllidia mediocris Yonow & Hayward, 1991: 20, figs. 11C-E, 13A (Mauritius).

Phyllidiella striata . - Yonow et al. 2002: 866, figs. 16f, 17b, 18a (Chagos).

Material.

Maldives: 22 × 11 mm pres., Gan, Maldives Island Expedition, 20 m depth, 28 July 1964, leg. PSD (NHMUK ref. no. M/01/0); 45 × 11 mm (NY-2, "tuberculate ridges, grey oral tentacles with grooves"), Blue Cave, North Malé Atoll, 25 m depth, 11 May 1990, leg. N Yonow; 47 × 9 mm (NY-9), Nakatcha Tila, North Malé Atoll, 27 m depth, 12 May 1990, leg. N Yonow; 26 × 10 mm (NY-17), Nakatcha Kura Tila, North Malé Atoll, 12 m depth, 12 May 1990, leg. N Yonow; three specimens 20 × 7 mm, 21 × 7 mm, and 22 × 8 mm (NY-20, 21, 22, "sole grey cf. rosans black"), Rasfaree Outer Reef, North Malé Atoll, 27 m depth, 13 May 1990, leg. N Yonow; four specimens 34 × 10 mm (NY-25, "broken crests, 2 rings, ring around anus, grey oral tentacles"), 34 × 13 mm (NY-26, " similar to NY-25 but crests more continuous, distinctly elongated"), 21 × 6 mm (NY-28, "median line + laterals + ring, metapodium with black median line, oral tentacles grey with black tip,"), 16 × 4 mm (NY-29, "black with broken med + laterals + 1 ring tubercles, oral tentacles grey pink"), Kuramathi, Rasdhu Atoll, 20 m depth, 13 May 1990, leg. N Yonow; six specimens 30 × 10 mm (NY- 48), 24 × 7 mm (NY- 50), 20 × 5 mm (NY- 56), 23 × 6 mm (NY- 57), 33 × 10 mm (NY- 58), 11 × 5 mm (NY- 66, "black with median + 2 lateral + 1 ring, pink tubercular crests"), Kandholudhu Tila, Ari Atoll, 10 m depth, 15 May 1990, leg. N Yonow; three specimens all pres. 16 × 10 mm (bent), 22 × 10 mm, 25 × 8 mm (NY dive 11, "pink & black crested"), Kandholudhu fringing reef, Ari Atoll, max 25 m depth, 15 May 1990, leg. N Yonow; three specimens pres. 22 × 8 mm bent, 22 × 10 mm curled, 25 × 10 mm (NY dive 12), Maayafushi fringing reef, Ari Atoll, max 30 m depth, 16 May 1990, leg. N Yonow; two specimens 26 × 10 mm (NY-104, "pink crested") and 12 × 6 mm (NY-105), Maaya Tila, Ari Atoll, 11 m depth, 18 May 1990, leg. N Yonow; 15 × 7 mm pres. (NY-108), Toroca, Ari Atoll, 10 m depth,19 May 1990, leg. N Yonow; 24 × 10 mm (NY-127), Maayafushi House Reef, Ari Atoll, 46 m depth, 22 May 1990, leg. N Yonow; 24 × 10 mm (NY-141), Small Banana Reef, North Malé Atoll, 25 m depth, 10 January 1991, leg. N Yonow; 20 × 7 mm (NY-147), Felidhoo House Reef, Fulidhoo Atoll, 20 m depth, 12 January 1991, leg. N Yonow; two specimens 24 × 18 mm (NY-149) and 24 × 7 mm (NY-150, "pink crested, 2 rings, smelly & exuded slime"), Fulidhoo House Reef, Felidhoo Atoll, 20 m depth, 12 January 1991, leg. N Yonow; 25 × 10 mm (NY-179, "pink crested"), Dhageti Tila, Ari Atoll, less than 17 m depth, 16 Jan 1991, leg. N Yonow; four specimens 40 × 13 mm (NY-199), 40 × 13 mm (NY-200), 25 × 10 mm (NY-201), 35 × 14 mm (NY-202), Bathala Faro, Ari Atoll, 15 m depth, 17 January 1991, leg. N Yonow; two specimens pres. 17 × 7 mm and 18 × 8 mm (NY dive 42, "pink broken crested"), Maaya Tila, Ari Atoll, 33 m depth, 18 January 1991, leg. N Yonow; 45 × 17 mm (NY-203, "pink broken crested"), Maayafushi lagoon, Ari Atoll, 22 m depth, 18 Jan 1991, leg. N Yonow; 13 × 5 mm (NY-205, "pink crested"), Bodhu Fahlu, Ari Atoll, 15 m depth, 19 Jan 1991, leg. N Yonow; 30 mm length (SH-6, "3 broken median lines, edge of mantle white"), Huravalhi Reef, Lhaviyani Atoll, 20 m depth, 1 March 1991, leg. S Harwood; 18 × 8 mm pres. (SH-55), Foteo West Reef, Felidhoo Atoll, 20 m depth, 25 April 1991, leg. S Harwood; 12 × 7 mm pres., Naifaro House Reef, Lhaviyani Atoll, 29 m depth, 3 November 1991, leg. H Debelius; 16 mm, Bathala Island, Ari Atoll, 10 m depth, 27 July 1995, leg. SG Buttress & RC Anderson; numerous individuals photographed & measured but not preserved, 13-35 mm, Maldives Expedition, N Yonow (see above and Yonow 1994, 1996) and 1986-1999, J Hinterkircher. - Christmas Island: 15 × 8 mm preserved (NHMUK 1899.5.26.13), Flying Fish Cove, leg. Sir J Murray (Andrews).

Remarks.

The recognition of Bergh’s species by Yonow et al. (2002) is further supported by these 45 specimens from the Maldives and Christmas Island. The Maldives appears to be a real hot spot for phyllidiid nudibranchs, supporting at least one endemic species ( Phyllidia koehleri , p. 61) and vast numbers of Phyllidiella striata and Phyllidiella rosans (see above). Phyllidiella striata is most similar to Phyllidiella rosans , but the (usually) broken dorsal ridges which are angled behind the rhinophores, which form a circle in front of the rhinophores, and which form a circle around the anus are charac teristic (Plate 71). Additionally, the two species differ ventrally, with Phyllidiella striata lacking the black pigmentation on the foot and oral tentacles (compare Fig. 22 and Fig. 24). Phyllidiella striata ranges from 13-35 mm while Phyllidiella rosans is usually larger, measuring up to 52 mm (p. 67) and is much darker ventrally.