Umbraculum f rom Florida

Dear Maris,
Thanks for these interesting photos. There are not many records of Umbraculum from anywhere in the tropical western Atlantic. Marcus & Marcus (1967) identified this species as Umbraculum plicatulum (Martens, 1881), but if there is a distinct species in the wstern Atlantic, then the earliest name would probably be Umbraculum bermudensis (Morch, 1875). As you will see in the Umbraculum mediterraneum Fact Sheet, there is no clear information on whether w should consider Umbraculum to be a single circumtropical species, or whether the Indo-West Pacific species U. umbraculum is distinct from the east Atlantic U. mediterraneum. And if they are different, is it possible that the west Atlantic species is U. mediterraneum or a third species? Clearly there needs to be some work done before a decision can be reached. Your photos are quite interesting as they clearly show that the tubercles have a pattern of radial or vertical wrinkles. This can also be seen in some Mark Thorpe & Katja Nagengast's photos of Umbraculum from the Canary Ids. I can't recall seeing similar wrinkles on Indo-West Pacific animals so it may suggest a distinction. This is pretty slender information for a definitive decision but certainly worth looking out for. I am putting your animals on the U. mediterraneum page, not because I am convinced there are distinct Atlantic and an IWP species but more to keep the question alive. I look forward to photos of other sea slugs from your area
Best wishes,
Bill Rudman