Pteraeolidia semperi
Blue dragon
Fiji · Pacific Ocen - Koro Sea
- Size
- 50–100 mm · max 216 mm
- Depth
- 2–55 m
- Native range
- Indo-West Pacific, including the Red Sea, the Philippines (type locality Bohol), Japan and Hawaii.
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Description
A large, centipede-like solar-powered aeolid, long known as Pteraeolidia ianthina; molecular work (Wilson & Burghardt 2015) restricted that name to Australian populations and reinstated P. semperi for the wider Indo-Pacific, itself probably a species complex. It farms zooxanthellae in its cerata and body wall, and stores stinging cells from its hydroid prey, which can sting human skin.
Share link: https://seaslugs.org.il/species/pteraeolidia-semperi-fiji-pacific-ocen-koro-sea/
Identification
Long, slender translucent tan body with many clusters of cerata along each side, giving a centipede-like look. Cerata range from dark purple and bluish to golden brown, depending on the zooxanthellae. Oral tentacles with two distinctive dark purple bands; rhinophores lamellate. Juveniles lacking zooxanthellae are whitish.
Similar species
Pteraeolidia ianthina of temperate and subtropical Australia is externally almost identical and was separated genetically. Small juveniles with few cerata can be mistaken for other aeolids.
Habitat & diet
Habitat
Coral and rocky reefs, often near drop-offs; 2–55 m, rarely shallower than 10 m in Hawaii.
Food
Hydroids, for example Pennaria disticha; it retains their nematocysts for defence.
