Gymnodoris sp.

Gymnodoris sp. Y

( Fig. 9L View FIGURE 9 )

Material examined. New Caledonia: North Province: Koumac, Northwest of Ilôt Kendec ( 20°40'S, 164°15.3'E), 0 m depth [Koumac 2.1 Expedition, stn. KM314 ], 21 Sep 2018, 1 specimen 4 mm preserved length (MNHN-IM-2019-26452, isolate JD80) GoogleMaps .

Description. Body narrow, elongate, with numerous low, conical tubercles ( Fig. 9L View FIGURE 9 ). Anterior end of notum with distinct, smooth velum; notal rim absent, velum merges with notum behind rhinophores. Posterior end of foot broad, tapering into pointy “tail.” Color translucent white, tubercles opaque white; posterior end translucent. Internal organs visible through body wall as cream, white masses. Rhinophores bulbous, with 7 lamellae, with same color as body. Gill with 14 short, bipinnate leaves, translucent white, with opaque white rachises, arranged in circle around anus. Foot narrower than notum, translucent yellow. Oral tentacles small, blunt.

Phylogenetic position. Gymnodoris sp. Y is sister to Gymnodoris sp. 31 (PP: 0.97, MLB: 79), and this clade is sister (PP: 1, MLB: 99) to another well supported clade (PP: 1, MLB: 99) including Gymnodoris cf. alba , Gymnodoris sp. X, and Gymnodoris bricei sp. nov. ( Fig. 1A View FIGURE 1 ).

Remarks. The specimen here examined is characterized by having a uniformly white coloration, with no other pigment except for the cream digestive gland. Only Gymnodoris sp. 15, described below, has a similar external coloration but it has a much smaller branchial leaves and a glandular structure posterior to the gill clearly visible. However, the specimen of Gymnodoris sp. Y illustrated by Knutson & Gosliner (2022) possesses orange pigment on the tubercles, velum rim, rhinophoral tips and posterior end of the body. These differences suggest there is intraspecific variation in this species or perhaps there is additional species diversity not recovered in the species delimitation analyses.