Gymnodoris sp. J

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 : 42

Gymnodoris sp. J

( Figs. 8E–G )

Material examined. New Caledonia: North Province: Koumac, Récif de l’Infernet ( 20°36.7'S, 164°14.7'E), 5 m depth [Koumac 2.1 Expedition, stn. KR301], 6 Sep 2018, 1 specimen 9 mm preserved length (MNHN-IM-2019-26415, isolate JD08) . New Caledonia: South Province: Nouméa, Île Freycinet, Ouémo ( 22°13.54'S, 166°23.4'E), 4–7 m depth [ Quinzaine des Nudibranches Expedition , stn. QNJF-OA], 17 Sep 2022, 1 specimen 8 mm preserved length (MNHN-IM-2019-26416, isolate JD91) . New Caledonia: North Province: Poum, South Ilôt Yandé ( 20°4.57'S, 163°49.59'E), 0 m depth [ABC Poum Expedition, stn. ABC58 ], 20 Jun 2023, 1 specimen 7 mm preserved length (MNHN-IM-2019-26417, isolate JD124) .

Description. Body oval to elongate, with numerous, small, rounded tubercles ( Figs. 8E–G ). Velum, notal rim not differentiated. Posterior end of foot broad, tapering gradually into pointy “tail.” Color translucent white, with orange-yellow tubercles; in some specimens internal organs visible through body wall as brown, yellow, and white masses. Rhinophores globular, with narrow tips, 8 lamellae, translucent white stalk, opaque club with orange tips. Gill with 18–20 small, simple, white leaves, arranged in a circle around anus, but appears open in one specimen. Foot narrower than notum, opaque white; oral tentacles small, blunt.

Phylogenetic position. Gymnodoris sp. J is sister to Gymnodoris sp. I (PP: 0.99, MLB: 79) but the position of this clade within the broader phylogeny of Gymnodoris is poorly supported ( Fig. 1A ).

Remarks. Based on the material here examined, Gymnodoris sp. J could be a species complex. Knutson & Gosliner (2022) reported one specimen of this species from the Philippines. Here we examined three additional specimens from New Caledonia, significantly extending the known range. Knutson & Gosliner (2022) did not provide illustrations of their specimen, but examination of the specimens from New Caledonia revealed some differences. Two specimens (MNHN-IM-2019-26415 and MNHN-IM-2019-26416) appear to be distinct as their body color is more opaque and the gill leaves form a complete circle. These two specimens are in the same clade. The other specimen (MNHN-IM-2019-26417), which is in the same clade as the specimen examined by Knutson & Gosliner (2022) and displays some external differences as the body is more translucent and the gill circle appears open posteriorly, however the species delimitation analyses recovered all four specimens as members of the same species. More research on this group with additional specimens is needed to determine the exact number of species in this complex.

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 8. Gymnodoris cf. alba (Bergh, 1877), Gymnodoris sp. AB, Gymnodoris sp. J, and Gymnodoris sp. M, photographs of live animals showing color variation. A. G. cf. alba, specimen from Koumac, New Caledonia (MNHN-IM-2019-26421, isolate JD19). B. G. cf. alba, specimen from Koumac, New Caledonia (MNHN-IM-2019-26422, isolate JD38). C. G. sp. AB, specimen from Koumac, New Caledonia (MNHN-IM-2019-26506, isolate JD62). D. G. sp. AB, specimen from Koumac, New Caledonia (MNHN-IM-2019-26501, isolate JD61). E. G. sp. J, specimen from Koumac, New Caledonia (MNHN-IM-2019-26415, isolate JD08). F. G. sp. J, specimen from Nouméa, New Caledonia (MNHN-IM-2019-26416, isolate JD91). G. G. sp. J, specimen from Poum, New Caledonia (MNHN-IM-2019-26417, isolate JD124). H. G. sp. M, specimen from Koumac, New Caledonia (MNHN-IM-2019-26482, isolate JD65). I. G. sp. M, specimen from Poum, New Caledonia (MNHN-IM-2019-26483, isolate JD110). J. G. sp. M, specimen from Poum, New Caledonia (MNHN-IM-2019-26485, isolate JD98). K. G. sp. M, specimen from New Caledonia: Loyalty Is.: Ouvéa, (MNHN-IM-2019-26484, isolate JD161). L. G. sp. M, specimen from New Caledonia: Loyalty Is.: Ouvéa, (MNHN-IM-2019-26523, isolate JD185).