These tiny Costasiella Sp. 1 were found grazing on some mudleaf or Avrainvillea amadelpha alongside a few Costasiella kuroshimae.  One of them was notably larger than the C. kuroshimae — likely 4-5 mm.  Imagine an animal less than 1/4 of an inch, in a sandy surge zone on a piece of algae covered in sand and you’ll understand why it was such a gift to find these.  The most notable identifying characteristics:  a light white/cream body with white speckles, a dark mask behind the eye spots and cerata that have tinges of green, orange and blue — sometimes quite iridescent. These animals were found in less than 10 ft (3 metres) in Ma’alaea Bay, Maui.  For more images and taxonomic information please see Sea Slugs of Hawaii.