Conchoderma virgatum (Spengler, 1790)
sent me this photo of a barnacle she found on a dive boat mooring
float off west Oahu. I sent the photo to barnacle expert William
Newman at the Scripps Institute. He replied:
It's Conchoderma virgatum, and it belongs to the ancestral
line that gave rise to the rabbit eared barnacle of whales, C.
auritum, and while usually found on floating objects (fishing
floats, boats, buoys etc.) it also occurs of turtles, swimming crabs,
spiny fishes (attached where skin has been damaged, or to parasitic
copepods on fish) and also cetaceans.
species occurs worldwide in warm waters.