Gymnodoris striata ( Eliot, 1908 )

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 : 34

Gymnodoris striata ( Eliot, 1908)

( Figs. 6A–B )

Trevelyana striata Eliot, 1908: 100–101 . Type locality: Undetermined , either Suez, Egypt or in the neighborhood of “Suakim” [= Sawakin, Sudan].

Material examined. New Caledonia: Loyalty Is.: Ouvéa, Pont de Mouly ( 20°41.91'S, 166°28.33'E), 5 m depth [Quinzaine des Nudibranches Ouvéa Expedition, stn. QUP37, night dive], 14 Jan 2024, 1 specimen 12 mm preserved length (MNHN-IM-2019-26448, isolate JD182); 1 specimen 13 mm preserved length (MNHN-IM-2019-26449, isolate JD165) .

Description. Body oval to elongate, with several low, longitudinal ridges on dorsum, anterior and posterior to gill ( Figs. 6A–B ). Velum and notal rim distinct, narrowing anteriorly and posteriorly into keel. Posterior end of foot wide, forming a broad tail. Color opaque white, ridges and notal rim orange. Rhinophores bulbous, with 9 lamellae, white stalk, orange-red club. Gill with 12 large, elongated, bipinnate leaves, opaque white with orange rachises, arranged in a transverse line. Foot wider than notum, dirty white, surrounded by orange line.

Phylogenetic position. Gymnodoris striata is a well-supported monophyletic group (PP: 1, MLB: 100), included in a clade (PP: 1, MLB: 93) containing three undescribed species: G. sp. 60, G. feyae sp. nov., and G. bernardae sp. nov. ( Fig. 1A ).

Remarks. Trevelyana striata was originally described by Eliot (1908) from northeast Africa as white and thick, with bright dark yellow well-defined bands; one of the lines surrounds the mantle and foot and the others, which are broken, extend down the dorsal and sides of the body. This is a very characteristic color pattern, which matches the current usage of the name ( Yonow, 2008; Hervé, 2010; Nakano, 2018; Gosliner et al., 2018) as well as the material here examined. Moreover, the molecular species delimitation analyses including sequences from GenBank confirmed that specimens from the Indian Ocean and the western Pacific, including the specimens here examined are conspecific, corroborating this species is widespread and well characterized in the literature.

Gymnodoris striata has been previously reported from New Caledonia by Risbec (1928) from Nouméa and by Hervé (2010) from Poindimié, both as Analogium striatum .

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 6. Gymnodoris striata (Eliot, 1908), Gymnodoris suggens (Risbec, 1928), and Gymnodoris okinawae Baba, 1936, photographs of live animals showing color variation. A. G. striata, specimen from New Caledonia: Loyalty Is.: Ouvéa, (MNHN- IM-2019-26449, isolate JD165). B. G. striata, specimen fromNew Caledonia: Loyalty Is.: Ouvéa, (MNHN-IM-2019-26448, isolate JD182). C. G. suggens, specimen from Poum, New Caledonia (MNHN-IM-2019-26455, isolate JD100). D. G. suggens, specimen from Poum, New Caledonia (MNHN-IM-2019-26456, isolate JD105). E. G. suggens, specimen from Poum, New Caledonia (MNHN-IM-2019-26505, isolate JD107). F. G. suggens, specimen from Poum, New Caledonia (MNHN-IM-2019- 26520), isolate JD132). G. G. suggens, specimen from Poum, New Caledonia (MNHN-IM-2019-26512, isolate JD138) H. G. suggens, specimen from Poum, New Caledonia (MNHN-IM-2019-26510, isolate JD134). I. G. suggens, specimen from Poum, New Caledonia (MNHN-IM-2019-26509), isolate JD135). J. G. suggens, specimen from Poum, New Caledonia (MNHN-IM- 2019-26508, not sequenced). K. G. suggens, specimen from Mont Dore, New Caledonia, photo Y. Thévenet (MNHN-IM-2019- 26513, not sequenced). L. G. okinawae, specimen from Ouaième, New Caledonia (MNHN-IM-2019-26528, isolate JD178), photo A. Doulas. M. G. okinawae, specimen from Nouméa, New Caledonia (MNHN-IM-2019-26450, isolate JD168).