Cyerce takanoi, Moreno & Medrano & Gosliner & Wilson & Krug & Valdés, 2025

Moreno, Karina, Medrano, Sabrina, Gosliner, Terrence M., Wilson, Nerida G., Krug, Patrick J. & Valdés, Ángel, 2025, Phylogenetic systematics of the genus Cyerce Bergh, 1870 (Mollusca: Heterobranchia: Sacoglossa: Caliphyllidae) from the Pacific and Indian oceans with descriptions of nine new species, Zoological Journal of the Linnean Society 204 (1) : -

Cyerce takanoi sp.nov.

( Figs 2E, 7)

LSID: zoobank.org:act: 8B5B7295-12BE-4BB2-9266- F5D560A39721.

Type material

Holotype: Pouebo , New Caledonia, 23 Sep 2018, leg. T. Takano, 1.5 mm preserved length, dissected (isolate AV487, MNHN IM-2013-86235 ).

Other material examined

Pouebo , New Caledonia, 23 Sep 2018, leg. T. Takano, 1 specimen 2 mm preserved length, dissected (isolate AV484, MNHN IM-2013-86234 ) .

Range

New Caledonia (present study).

Description

External morphology: Body colour olive green to black. Pericardium elevated, oval, light orange with white speckling ( Fig. 2E). Head light grey, with black Y-shaped band extending from base of head to rhinophoral tips; two dark orange patches along sides of head, another at forehead. Rhinophores long, dark grey to black with two striations formed by green to fluorescent orange dots. Tentacles with similar pattern as rhinophores. Cerata inflated, fan-shaped, black, scattered with few elevated bright orange spots; few white and fluorescent specks. Cerata sub-marginally outlined with red-orange to bright orange band on both sides; sub-marginal band covering several small white clusters. Cerata margin outlined with white band and several minute white specks; bordered by two black bands. Foot wider than body. Dorsally, foot black with greyish margin; margin with white speckling. Posterior end of foot extends further than body, pointed.

Internal morphology: Radula with 10 teeth in a 2-mm preserved length specimen (MNHN IM-2013-86234); 5 teeth on descending limb, 5 teeth on ascending limb ( Fig. 7A). Radular teeth moderately elongate with rounded tips. Leading tooth about 150 µm in length, with two rows of ~8 denticles visible along either side of tooth ( Fig. 7B). Denticles recurved, triangular in shape; all about same size (those visible). Ascus small, with few teeth. Penis not observed.

Ecology

Specimens found in association with the green algae Chlorodesmis spp.

Etymology

This species is named in honour of Tsuyoshi Takano who collected the algae in which this species was found and in appreciation for his help and friendship to AV during the Koumac expeditions.

Remarks

Specimens of Cyerce takanoi sp. nov. from New Caledonia were originally identified as C. nigricans . However, these specimens were distinct from C. nigricans in all species delimitation methods ( Fig. 1A). As noted, C. takanoi sp. nov. and C. nigricans share similar external morphological characteristics, such as having black cerata with elevated orange spots, an infra-marginal yellow-orange band on the cerata, and white band outlining the margin of the cerata. However, the head pattern is different between these two species: C. nigricans has a bold medial longitudinal orange band on the head with two bold orange striations extending across the rhinophores, traits not observed in C. takanoi sp. nov. Bergh (1873) also described yellow longitudinal striations along the dorsum of the holotype, observed in our specimens of C. nigricans but not in C. takanoi sp. nov. The radula of Cyerce takanoi sp. nov. is very similar to that of C. nigricans but the teeth are considerably smaller. The number of teeth was not considered directly comparable due to the size differences of the specimens examined.