Tuesday, June 16, 2020

[Mollusca • 2020] Phestilla viei • A New Species of Coral-feeding Nudibranch (Gastropoda) from the Gulf of Thailand

Phestilla viei Mehrotra, Caballer & Chavanich  

in Mehrotra, Arnold, Wang, Chavanich, Hoeksema & Caballer, 2020. 

The validity and position of the Indo Pacific genus Phestilla Bergh, 1874 (Fionoidea: Trinchesiidae) have been subject of some controversy as a result of several recent studies, which have sequentially synonymized or re-established it. At present, the genus includes eight valid species, the most of them described in the nineteenth and twentieth centuries, and all but one feeding on scleractinian corals of four genera: Porites Link, 1807 (Poritidae), Tubastraea Lesson, 1830, Dendrophyllia Blainville, 1830 (Dendrophylliidae) and Montipora Blainville, 1830 (Acroporidae). The discovery of an unknown Phestilla species feeding on Pavona explanulata (Lamarck, 1816) (Agariciidae) in Koh Tao, Thailand, motivates this work, in which this new species is described providing morphoanatomical and molecular characters. In addition, its systematic position and ecological significance as coral parasite are discussed.

Keywords: Fionoidea, Trinchesiidae, Ecto-parasite, Phestilla Bergh, 1874, Pavona explanulata (Lamarck, 1816), Camouflage

Fig. 1 Phestilla viei Mehrotra, Caballer & Chavanich sp. nov. on Pavona explanulata.
 a Living specimen (28 mm long) in dorso-lateral view with low symbiont density; b Specimen (23 mm long) camouflaged among the coral; c Living specimen (17 mm long) in lateral view; d Two specimens with low symbiont density with their egg masses. Durusdinium sp. associated to Phestilla viei sp. nov; e General view of a section of a single ceras; f Durusdinium sp. in the ceras matrix; g Details of the symbiont cells

Order Nudibranchia Cuvier, 1814 (in Blainville 1814).
Superfamily Fionoidea Gray, 1857.

Family Trinchesiidae Nordsieck, 1972.

Genus Phestilla Bergh, 1874.

Phestilla viei Mehrotra, Caballer & Chavanich sp. nov.

Phestilla sp.: Fritts-Penniman 2016: 116, Fig. 3.1 E.
Phestilla sp. 2: Gosliner et al. 2008: 372; Gosliner et al. 2015: 357.
Tenellia sp. 83: Gosliner et al. 2018: 300.
?Tenellia D4: Fritts-Penniman et al. 2020: Fig. 1G.

Derivatio nominis: Phestilla viei Mehrotra, Caballer & Chavanich sp. nov. is named in honor of Mr. Vie Panyarachun for his years of facilitating citizen science and contributions in curating records of sea slug diversity in Thai waters, and his continued efforts as a marine naturalist.

Rahul Mehrotra, Spencer Arnold, Adam Wang, Suchana Chavanich, Bert W. Hoeksema and& Manuel Caballer. 2020. A New Species of Coral-feeding Nudibranch (Mollusca: Gastropoda) from the Gulf of Thailand. Marine Biodiversity. 50: 36. DOI: 10.1007/s12526-020-01050-2

A New Species of Coral-Eating Nudibranch