A green sacoglossan of about 3 cm (1.2 in), its flaps edged white and the back finely dark-spotted. It sits on filamentous green weed growing over reef rock, where the color match does most of the hiding.
The species was named for Thomas Thompson, whose work on opisthobranch molluscs through the second half of the twentieth century underpins much of what is known about the group. Like the rest of the family it lives by piercing algal cells and draining them, keeping the chloroplasts alive inside its tissues so that sunlight supplements the diet. Records from this coast are sparse; whether that reflects real scarcity or the simple fact that a three-centimetre green animal on green weed is rarely noticed is an open question, and one that applies to most of this group.
- green body with a white-edged margin on the flaps
- fine dark spotting over the back
- small, up to 3 cm
- on filamentous green weed
