Thysanozoon or Acanthozoon B
photo & video: Karolle Wall, Maui.

Karolle photographed this worm at Sugar Beach, Maui, "in a few feet of water on a nearshore shelf that forms a tide pool at lowest tides." She writes: "It could be a juvenile as it was no bigger than 12 mm. I’ve attached a video as well as photos. Very beautiful to watch. Appeared a solid white, but looks more transparent close up. Papillae are quite raised and almost conical. — a pepper-like speckling in between and on some of the papillae."

Cory Pittman writes: It belongs with those species listed on ... Leslie's CD as "Thysanozoon or Acanthozoon spp." However, the translucent-white body with opaque-white and black flecks doesn't match any of the illustrated species well enough for me to suggest a match. I see the flecks become more brownish apically on the papillae. But, that still doesn't help much... I suppose there's some chance that it's a juvenile that could develop more uniform pigmentation with growth. But, most flatworms have their pattern pretty much "set" by 12 mm... A bit of on-line searching (not comprehensive) yielded a somewhat similar animal from Singapore (based on background, opaque-white flecks and eye spots). But, that one lacks the dark flecks....

https://singapore.biodiversity.online/species/A-Platyhelminthes-000049

Update: Karolle photographed a similar worm of about the same size in March 2022 (photo 3). She observes that it's a bit darker and wonders if it's "Thysanozoon or Acanthozoon B" or something else.. Cory Pittman writes: It could be argued as either a young "Thysanozoon or Acanthozoon A" or "Thysanozoon or Acanthozoon B". Looking at the photos, again, there's also some chance that "B" actually is a young "A"...

Thysanozoon or Acanthozoon A

SInce we really don't know, and because species of worms often mimic each other, it seems simplest to keep A & B separate for now.

BACK to covered with papillae