Gymnodoris sp.

Souza-Canal, Jade De & Valdés, Ángel, 2025, The genus Gymnodoris Stimpson, 1855 (Mollusca, Nudibranchia) in New Caledonia, with descriptions of eleven new species, Zootaxa 5710 (1), pp. 1-73 : 46

Gymnodoris sp. Y

( Fig. 9L )

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) .

Description. Body narrow, elongate, with numerous low, conical tubercles ( Fig. 9L ). 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 ).

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.

Figures

FIGURE 1. A. Bayesian consensus phylogenetic tree of the concatenated dataset including PP above branches and MLB below branches. Branches fully supported (PP: 1, MLB: 100) marked with asterisks. New species described in this paper highlighted in red font and illustrated; other species reported from New Caledonia in this study highlighted in blue font. Clades are collapsed according to the results of the ASAP and bPTP species delimitation analyses. B. Histogram representing the distance plot from the ASAP analysis using the COI gene showing pairwise p-distances (Kimura 2 model) among candidate species. The dashed line represents the distance threshold provided by the lowest ASAP score for species delimitation.

FIGURE 9. Gymnodoris sp. O, Gymnodoris sp. Q, Gymnodoris sp. V, Gymnodoris sp. X, and Gymnodoris sp. Y, photographs of live animals showing color variation. A. G. sp. O, specimen from Koumac, New Caledonia (MNHN-IM-2019-26495, isolate JD81). B. G. sp. O, specimen from Koumac, New Caledonia (MNHN-IM-2019-26494, isolate JD74). C. G. sp. O, specimen from Poum, New Caledonia (MNHN-IM-2019-26496, isolate JD112). D. G. sp. O, specimen from Poum, New Caledonia (MNHN-IM-2019-26499, isolate JD125). E. G. sp. O, specimen from Poum, New Caledonia (MNHN-IM-2019-26497, isolate JD115). F. G. sp. O, specimen from Poum, New Caledonia (MNHN-IM-2019-26498, isolate JD117). G. G. sp. O, specimen from Poum, New Caledonia (MNHN-IM-2019-26500, isolate JD139). H. G. sp. Q, specimen from Koumac, New Caledonia (MNHN-IM-2019-26521, isolate JD57). I. G. sp. V, specimen from Nouméa, New Caledonia (MNHN-IM-2019-26480, isolate JD90). J. G. sp. V, specimen from Nouméa, New Caledonia (MNHN-IM-2019-26479, isolate JD142), photo Y. Thévenet. K. G. sp. X, specimen from Poum, New Caledonia (MNHN-IM-2019-26423, isolate JD108). L. G. sp. Y, specimen from Koumac, New Caledonia (MNHN-IM-2019-26452, isolate JD80).