"The worm is probably Asterophilia carlae. Asterophilia culcitae has recently been described from Vietnam. It also lives on Culcita, Luidia, & other asteroids so it could have the same geographic distribution as Asterophilia carlae. Unfortunately the characters which separate the 2 species can't be seen without a microscope. "
Comment from Leslie Harris
The worm is probably Asterophilia carlae. Asterophilia culcitae has recently been described from Vietnam. It also lives on Culcita, Luidia, & other asteroids so it could have the same geographic distribution as Asterophilia carlae. Unfortunately the characters which separate the 2 species can't be seen without a microscope.