Gymnodoris fleuroti De Souza-Canal & Valdés, 2025

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 : 56-57

Gymnodoris fleuroti De Souza-Canal & Valdés sp. nov.

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( Figs. 13C , 14C–D , 15A )

Type material. Holotype: 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 4 mm preserved length (MNHN-IM-2019- 26428, isolate JD113).

Description. Body narrow, elongate, with several low conical tubercles mainly arranged around notal rim, a few on dorsum, velum. Velum differentiated with 12 tubercles, continuing posteriorly into notal rim ( Fig. 15A ). Color translucent white, tubercles orange-red, thin orange-red line connecting velum tubercles; posterior end of foot translucent. Internal organs visible through body wall as orange, white masses. Rhinophores conical, with 6 lamellae, white stalk, club, with orange tips. Gill inconspicuous, with of 6 small, simple, white leaves, arranged in a circle around anus, opened posteriorly. Foot narrower than notum, opaque white. Oral tentacles small, flattened.

Radular formula 15 × 7.0. 7 in the 4 mm preserved length holotype (MNHN-IM-2019-26428). Innermost lateral teeth large, hook-shaped, with curved smooth cusps ( Fig. 13C ). Other lateral teeth elongate straight, with short, curved cusps, becoming smaller towards outer edge of half-row ( Fig. 13C ).

Reproductive system with an elongate, broad, curved ampulla, connecting to female gland complex, prostate ( Fig. 14C ). Prostate large, tubular, curved around bursa copulatrix, narrowing into a highly convoluted deferent duct, opening into a common atrium with vagina. Vagina long, slightly curved, connecting into bursa copulatrix near seminal receptacle connection. Bursa copulatrix spherical, about 5 times as large as oval seminal receptacle. Penial spines small (about 50 µm long), triangular ( Fig. 14D ).

Phylogenetic position. The phylogenetic position of Gymnodoris fleuroti sp. nov. is unresolved due to low support values ( Fig. 1A ).

Etymology. This species is named in honor of Dominique Fleurot, naturalist, author of several floristic treaties, and coordinator of the ABC (Atlas de la Biodiversité Communale) project in Poum, New Caledonia. The ABC project is a large-scale biodiversity census operation centered in Poum, which produced the holotype of Gymnodoris fleuroti sp. nov. and many other species.

Remarks. Gymnodoris fleuroti sp. nov. is externally similar to Gymnodoris mariefranceae sp. nov., but these two species are genetically distinct, recovered in separate groups in the species delimitation analyses. Some differences are visible and appear to be consistent, the orange tubercles of G. mariefranceae sp. nov. are larger and more abundant on the center of the dorsum. Also, G. mariefranceae sp. nov. possesses a branched glandular structure visible at the posterior end of the foot. Internally, the two species are readily distinguishable by the shape of the penial spines, triangular in G. fleuroti sp. nov., elongated in G. mariefranceae sp. nov. The radulae of the two species are similar but G. fleuroti sp. nov. has less lateral teeth, more curve at the tip.

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 13. Gymnodoris knutsonae sp. nov., Gymnodoris fleuroti sp. nov., and Gymnodoris mariefranceae sp. nov., scanning electron micrographs of the radulae. A–B. G. knutsonae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM-2019-26380, isolate JD53), inner lateral teeth (A), outer lateral teeth (B). C. G. fleuroti sp. nov., holotype, Poum, New Caledonia (MNHN- IM-2019-26428, isolate JD113), half-row. D–E. G. mariefranceae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM- 2019-2624, isolate JD16), inner lateral teeth (D), outer lateral teeth (E).

FIGURE 14. Gymnodoris knutsonae sp. nov., Gymnodoris fleuroti sp. nov., and Gymnodoris mariefranceae sp. nov., and Gymnodoris lebouteillerorum sp. nov., drawings of reproductive systems. A–B. G. knutsonae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM-2019-26382, isolate JD64), general view of reproductive organs (A), penial spines (B). C–D. G. fleuroti sp. nov., holotype, Poum, New Caledonia (MNHN-IM-2019-26428, isolate JD113), general view of reproductive organs (C), penial spines (D). E–F. G. mariefranceae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM-2019-26389, isolate JD20), general view of reproductive organs (E), penial spines (F). G–H. G. lebouteillerorum sp. nov., holotype, Koumac, New Caledonia (MNHN-IM-2019-26486, isolate JD66), general view of reproductive organs (G), penial spines (H).

FIGURE 15. Gymnodoris fleuroti sp. nov., Gymnodoris mariefranceae sp. nov., Gymnodoris lebouteillerorum sp. nov., and Gymnodoris deniseae sp. nov., photographs of live animals showing color variation. A. G. fleuroti sp. nov., holotype, Poum, New Caledonia (MNHN-IM-2019-26428, isolate JD113). B. G. mariefranceae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM-2019-26392, isolate JD97). C. G. mariefranceae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM-2019- 26425, isolate JD31). D. G. mariefranceae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM-2019-2624, isolate JD16). E. G. mariefranceae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM-2019-26390, isolate JD21). F. G. mariefranceae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM-2019-26389, isolate JD20). G. G. mariefranceae sp. nov., holotype, Koumac, New Caledonia (MNHN-IM-2019-26391, isolate JD28). H. G. mariefranceae sp. nov., paratype, Koumac, New Caledonia (MNHN-IM-2019-26393, isolate JD37). I. G. lebouteillerorum sp. nov., holotype, Koumac, New Caledonia (MNHN- IM-2019-26486, isolate JD66). J. G. deniseae sp. nov., holotype, Poum, New Caledonia (MNHN-IM-2019-26463, isolate JD136). K. G. deniseae sp. nov., paratype, Poum, New Caledonia (MNHN-IM-2019-26465, isolate JD111). L. G. deniseae sp. nov., paratype, Poum, New Caledonia (MNHN-IM-2019-26466, isolate JD116). M. G. deniseae sp. nov., paratype, Poum, New Caledonia (MNHN-IM-2019-26467, isolate JD109). N. G. deniseae sp. nov., paratype, Poum, New Caledonia (MNHN- IM-2019-26468, isolate JD101). O. G. deniseae sp. nov., paratype, Poum, New Caledonia (MNHN-IM-2019-26464, isolate JD103).