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Additional Photos
pale
opaque
"tail" junction
interior
feeding
defecating
egg mass
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Stylocheilus longicauda
(Quoy & Gaimard, 1825)
Maximum size: about 55 mm.
Identification:
This
sea hare has a bright yellow body decorated with pale blue and
bright orange ocelli. Occasionally it may have faint brown spots. The "tail" is elongate and flattened.
Natural history:
Stylocheilus longicauda
is a planktonic species found primarily on drifting debris (although it
may also be found occasionally on mooring lines or buoys). The
elongate,
flattened "tail" allows it to cling tightly to its substrate. It is
seldom seen around the main islands but may be common at French
Frigate Shoals and elsewhere in the leewards. As with other members of
the genus, the ocelli may function as an aposematic signal. (Note 1) It lays a tangled, light yellow egg mass.
Distribution: Big Island, Maui, Oahu, French Frigate Shoals and Kure: circumtropical.
Taxonomic notes:
It was first
recorded in Hawaii from a lobster larvae collector at Kure by
Scott Johnson on June 16, 1980.
Photo: CP: 2006 CREEF
expedition; French Frigate Shoals; Oct. 25, 2006.
Observations and comments:
Note
1: The "blue spots with gold rings
on a gold background" aren't as precisely matched to the "blue and gold
ocelli on a cryptic background" found in the sea hares Stylocheilus striatus and Phycophila euchlora (as well as some unrelated mimics). However, all other
members of the mimicry complex are benthic. That may account for the
differences with the ocelli still serving as an aposematic signal. It's
also possible that they're a neutral trait that's been retained from shared ancestors....
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