A little mystery

Eric was at the Spud Point Marina docks in Bodega Harbor today (23 June 2024) doing some scouting for his summer class (which starts tomorrow!).  He noticed this tiny nudibranch that he didn't recognize.  It was only ~8.5 mm long.

It took us a little while to puzzle through this identification, but eventually we landed on a possibility -- Polycerella glandulosa, a species neither of us has seen before.  ADDENDUM (24 June 2024): Abby provided some feedback and we now think this is Bermudella angelensis (formerly Okenia angelensis).

Here's an illustration from the paper which first described Polycerella glandulosa:

 

Drawing from Behrens, D.W. and T.M. Gosliner.  1988. The first record of Polycerella Verrill, 1881, from the Pacific, with the description of a new species. The Veliger. 30(3): 319-324. 

Although many of the features match up pretty well, there are a few things that are still puzzling to us, so we'll be inquiring further about the identification.

ADDENDUM: Here's an illustration of Bermudella angelensis:

Drawing from Lance, J. (1966). New distributional records of some northeastern Pacific Opisthobranchiata (Mollusca: Gastropoda) with descriptions of two species. The Veliger. 9(1):69–81.

From what we can tell, Polycerella glandulosa is a southern species, with most records south of Morro Bay.  We don't know whether there are any records north of San Luis Obispo County.  ADDENDUM: Bermudella angelensis is also a more southern species, but it has been recorded in Sonoma County at least once, in May 2017.

Because this species would be unusual this far north, Eric recorded some video footage for the record (below).  [If you can't see the video player in the e-mail message, click on the title of the post above to go to the NHBH website.]

Thanks, Eric, for taking the time to document this interesting nudibranch!

ADDENDUM: And many thanks to Abby for pursuing the identification further and alerting us to Bermudella angelensis!