Anilao — 24 January 2026
- Location seen
- Anilao, Philippines
- Date seen
- 2026-01-24
Hypselodoris tryoni
Tryon's Hypselodoris
Hypselodoris tryoni. The individual in the foreground has a parasite living within the gills – note the two purple projections.© Di Syrett / MacroDivers.com
About this species
- Current scientific name
- Hypselodoris tryoni
- Common name
- Tryon's Hypselodoris
- Previous genera
- Risbecia
- Order
- Nudibranchia - Doridoidea (Dorids)
- Type
- Cryptobranchia (Cryptobranch dorids)
- ID confidence
- Confirmed
- Genus
- Hypselodoris
- Species
- tryoni
- Average size
- 70 mm
- Colours
- white, black, purple, brown
- Pattern
- Spots, Mottled, Edged mantle
- Body shape
- Oval
- Rhinophores
- Horizontal
- Gills
- External gill plume
- Similar species
- Goniobranchus leopardus, Goniobranchus geminus, Goniobranchus kuniei
Geographic Distribution
Western and central Pacific Ocean.
Identification
Used to be part of the Risbecia genus and noted for their high body profile. The simple (unbranched) but large gills are towards the rear of the animal and are retractable. Rhinophores lamellate and fully retractable.
Behaviour / Habitat
Often seen in pairs or small groups. Hypselodoris tryoni is one of the species that is often seen tailgating. One animal follows the mucus trail of another. Once the trailing nudi catches up with the first, it makes contact and continues the trailing behaviour with its head on the other's tail. Usually just two individuals but it may run to three or four.
General Notes
The head is often raised and lowered as it crawls.
Our Sightings
Lembeh — 7 September 2025
- Location seen
- Lembeh, Indonesia
- Date seen
- 2025-09-07
About our records
All sightings and photographs on this page are from our own dives. Locations shown are places where we have personally recorded this species. About MacroDivers.