Sclerodoris faninozi Innabi, Stout & Á. Valdés, 2023

Location: Yaene, Hachijo Island, Tokyo, Japan
Date: 2026/04/30
Length: 20mm
Depth: 10.0m
Water temperature: 23.0℃

Description

A small dorid nudibranch with a flattened, oval body and a coriaceous, hard-feeling dorsum. The dorsum is densely covered with small caryophyllidia, traversed by a longitudinal ridge, and bears several large, rounded tubercles. The branchial and rhinophoral sheaths are slightly elevated and irregular in shape, and the visceral hump rises above the rest of the mantle. Body ground color yellowish brown, with scattered opaque white pigment and patches of dark brown and dark gray. Branchial leaves and rhinophores dark brown. The gill comprises five short, tripinnate, upright leaves; the rhinophores are short and lamellated, with about 15 lamellae. Up to 25 mm in length.

Distribution

The type locality is Koumac, New Caledonia, where the holotype was collected at 0 m depth from blocks of dead coral on the margin of the fringing reef flat. The species was originally known only from this single specimen at Koumac. A specimen from Okinawa with a COI sequence matching S. faninozi at 99% identity has subsequently been obtained, suggesting a wider distribution across the western Pacific.

Etymology

The specific epithet faninozi honors Sébastien Faninoz, whose efforts were critical for organizing the Koumac expeditions.

Remarks

Molecular phylogenetic analyses recover Sclerodoris faninozi as sister to Sclerodoris tuberculata, the type species of the genus. Externally it closely resembles Sclerodoris coriacea from Zanzibar, but is distinguished by the presence of a longitudinal dorsal ridge, which is absent in S. coriacea. The holotype was found under a block of dead coral on a fringing reef flat, where its mottled color and rough dorsal texture render it highly cryptic against the surrounding rocks and sponges.