Reasoning recorded at review

• •High, elongate body with a relatively narrow mantle and reduced lateral overlap; the projecting foot is visible.
• •Cream-to-brown reticulate dorsum carries solid dark violet-brown spots with conspicuous white or pale halos.
• •The mantle edge is a narrow continuous violet-purple line rather than the broad band expected in Goniobranchus kuniei.
• •Visible rhinophore or gill pigment runs brown-purple along the rachis or lamellae rather than being confined to a purple tip.
• •The still clearly exposes the high elongate body, narrow mantle overlap, solid haloed spots, fine purple edge, and pigmented rhinophores.

Alternatives considered

• Goniobranchus leopardus

  Why plausible: A member of the same tryoni colour group and capable of similar pale-ringed dark markings.

  Comparison: A complete view should confirm the absence of hollow-square or clustered leopard markings and the broader mantle overlap expected in G. leopardus.

• Goniobranchus kuniei

  Why plausible: Shares large purple-brown, often pale-ringed dorsal markings.

  Comparison: Confirm across the whole animal that the mantle remains high and narrow and the purple border remains fine rather than forming the broad band of G. kuniei.

• Goniobranchus cavae

  Why plausible: Reported as externally similar to H. tryoni in the specimen-backed Sangihe comparison.

  Comparison: An unobscured colour-corrected view of all rhinophores and gills should confirm pigment along the full rachis rather than white appendages with purple mainly at the tips.