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 : 40

Gymnodoris sp. AB

( Fig. 8C–D )

Material examined. New Caledonia: North Province: Koumac ( 20°32.9'S, 164°05.7'E), 3 m depth [Koumac 2.3 Expedition, stn. KD565 ], 15 Nov 2019, 1 specimen 6 mm preserved length (MNHN-IM-2019-26501, isolate JD61) . New Caledonia: North Province: Koumac, Ilôt Double ( 20°28'S, 164°07.6'E), 0 m depth [Koumac 2.1 Expedition, stn. KM309 , sand-mud flat with dead corals and seagrass, rocky shore with seagrass patches, lagoon with mangroves, seagrass and green algae], 17 Sep 2018, 1 specimen 6 mm preserved length (MNHN-IM-2019- 26506, isolate JD62) .

Description. Body narrow, elongate, with few, low, conical tubercles on dorsum, larger and more densely arranged on the posterior end and the notal rim ( Figs. 8C–D ). Velum differentiated, with several tubercles, continuing posteriorly into notal rim. Posterior end of foot tapering gradually into a blunt “tail.” Color translucent white to reddish brown on posterior end in one specimen, tubercles red with blurry edges, faint red line connecting tubercles in velum, continuing interrupted along notal rim. Some internal organs visible through body wall as brown, orange and white masses. Rhinophores conical, with 7 lamellae, clubs red antero-distally, white postero-proximally, stalks translucent white. Gill with 8 short, bipinnate, translucent white with orange pigment, opaque white bases, arranged in circle around anus opened posteriorly. Foot narrower than notum, translucent white; oral tentacles absent.

Phylogenetic position. The phylogenetic position of Gymnodoris sp. AB is unresolved ( Fig. 1A ).

Remarks. Very similar to the preceding species, but it possesses less dorsal tubercles and the gill circlet is not complete posteriorly. It is also similar to Gymnodoris alba sensu Nakano (2018) and Rudman & Darvell (1990) but lacks red lines on the branchial leaves.

Knutson & Gosliner (2022) reported this species from the Philippines, but did not provide illustrations of the live animal. The two specimens here examined were recovered as different species in the species delimitation analyses, but they are morphologically similar to each other, so they were tentatively included in the same candidate species .

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).