December 30, 2023

Eastern Pacific Nudibranch News: Four Species Renamed: No More Genus Okenia in California

Four name changes to finish out 2023. Your IDs already have changed automatically; you don't need to do anything. :-)

1) Okenia rosacea is now Ceratodoris rosacea. The common name will remain Hopkins' Rose Nudibranch.

2) Okenia plana is now Ceratodoris plana, and the common name has been updated to Flat Goniodorid.

3) Okenia angelensis is now Bermudella angelensis, and the common name has been updated to Los Angeles Goniodorid.

4) Okenia felis is now Goniodoridella felis. The common name has been updated to Cat Goniodorid.

Here's the paper, which also includes more changes outside the Eastern Pacific (thanks @hsini_lin for posting the link):

Paz-Sedano, S.; Moles, J.; Smirnoff, D.; Gosliner, T. M.; Pola, M. (2023). A combined phylogenetic strategy illuminates the evolution of Goniodorididae nudibranchs (Mollusca, Gastropoda, Heterobranchia). Molecular Phylogenetics and Evolution. 107990.

Posted on December 30, 2023 11:21 PM by anudibranchmom anudibranchmom | 2 comments | Leave a comment

November 12, 2023

Eastern Pacific Nudibranch News: Apata pricei is correct as printed in Behrens et al, 2022

Retraction of last week’s correction from the authors: “After much discussion and research we have determined that the book [Behrens et al, 2022] is correct as printed.” So the “southern” nudibranch REMAINS Apata pricei, and the “northern” form (without the reddish bands on the cerata) is Apata cf. pricei.

Good luck re-correcting your IDs and a big thank you to @lutea11 and @jeffgoddard.

@tgosliner @jeffgoddard @hsini_lin @juliabohemian @walkabata @chilipossum @mcduck @passiflora4 @nudibitch @helgeweissig @erwinkoehler @chlorophilia @lemurdillo @jpsilva @imlichentoday @kueda @kestrel @rebeccafay @jannvendetti @hfb @lutea11

Posted on November 12, 2023 10:50 PM by anudibranchmom anudibranchmom | 3 comments | Leave a comment

November 07, 2023

Eastern Pacific Nudibranch News: Correction re Apata pricei and Apata cf. pricei

Time to take a second look at your Apata observations, and time to get out a pencil and annotate your field guide.

Correction from the authors to "Nudibranchs and Sea Slugs of the Eastern Pacific," 2022: Please note that the bold subheads on page 122 of Apata pricei and Apata cf. pricei were inadvertently swapped. The first, more colorful slug on page 122 should be labeled Apata cf pricei, and the second slug should be labeled Apata pricei. The authors also inform me that the range of Apata pricei has been updated to Korea, Japan, and Russia through Ketchikan, Alaska to Monterey Bay, California.

THEREFORE, according to the Bible, we have three zones to look at:

1) North of Crescent City, California thorough Alaska, plus Korea, Japan and Russia: You're 100% Apata pricei (though there's possibly a subspecies in Asia, which we won't get into here).

2) South of Monterey Bay, California: You're 100% Apata cf. pricei. Please change all of your observations to Genus Apata (no species-level ID) and in Description, write "Apata cf. pricei" until these are formally described.

3) Overlap Zone in California (Crescent City to Monterey Bay): These observations will need to be re-identified manually; please look for the following ID clues:

Apata pricei: no reddish band on cerata and opaque white on most of the length of the rhinophores
Apata cf. pricei: reddish band near the tip of the cerata, with opaque white on tips of rhinophores only

BOTH COMMON NAMES on iNat ("Smooth Tooth Aeolid" and "Price's Aeolid") refer to the true Apata pricei; Apata cf. pricei does not have a common name and is unlikely to have one until it is formally described.

Good luck correcting your IDs and a big thank you to @lutea11 for all her work on this difficult genus and the excellent field guide.

@tgosliner @jeffgoddard @hsini_lin @juliabohemian @walkabata @chilipossum @mcduck @passiflora4 @nudibitch @helgeweissig @erwinkoehler @chlorophilia @lemurdillo @jpsilva @imlichentoday @kueda @kestrel @rebeccafay @jannvendetti @hfb @lutea11

Posted on November 07, 2023 11:12 PM by anudibranchmom anudibranchmom | 7 comments | Leave a comment

October 30, 2023

California Nudibranch Guide updated

Hi Everyone,

I made a number of updates to our California Nudibranch Guide, notably the addition of undescribed species, to more closely conform to Behrens, et al, 2022. If you have time, please take a look and message me with any edits/suggestions.

Please note that until a paper is actually published or a split/lump/new species is put down in writing, I will leave the taxonomy in this guide as it is on iNaturalist (for example, Coryphella trilineata).

Does anyone have a photo of Eubranchus sp. 3 they'd be willing to contribute?


  • Robin
Posted on October 30, 2023 08:32 PM by anudibranchmom anudibranchmom | 0 comments | Leave a comment

June 21, 2023

New Split: A Spanish dancer? No! A troupe of dancers!

I usually confine myself to E. Pacific nudibranch news, but I thought enough underwater photographers might be interested in this taxonomic revision, published yesterday. Who doesn't love these huge, bright, squishy dorids?

Tibiriçá, Y., Pola, M., Pittman, C. et al. A Spanish dancer? No! A troupe of dancers: a review of the family Hexabranchidae Bergh, 1891 (Gastropoda, Heterobranchia, Nudibranchia). Org Divers Evol (2023).

Posted on June 21, 2023 07:02 PM by anudibranchmom anudibranchmom | 0 comments | Leave a comment

June 11, 2023

Eastern Pacific Nudibranch News: First Rfemsia macfarlandi on iNat, AND a southern range extension!

Thank you Sonja @squishlefish for the find with Laura @thetidepooler of Refemsia macfarlandi, a very small, rare species of heterobranch today. 😊 A bit of a weirdo, it is the only species in the genus. It was first described in 1991 by @tgosliner and according to Behrens, et al, 2022, it ranges from Lincoln County, Oregon to Long Beach, California. However, today’s observation is from La Jolla, California! @jeffgoddard and @lutea11 check this out. Possibly more evidence of Eastern Pacific species moving southward (La Niña!?) this year?

Congratulations on a very interesting find!!

Posted on June 11, 2023 01:42 AM by anudibranchmom anudibranchmom | 1 comment | Leave a comment

March 09, 2023

Eastern Pacific Nudibranch News: Ancula pacifica accepted by WoRMS

Thank you @jeffgoddard for pointing out that WoRMS has accepted Ancula pacifica:

"I just noticed that WoRMS now accepts Ancula pacifica, following Behrens et al. (2022), who I know considered morphological and molecular genetic evidence, including Ian Smith's extensive account of A. gibbosa: Ancula pacifica MacFarland, 1905 applies only to Ancula in the NE Pacific with three orange lines on the body between the rhinophores and gills, so this change on iNaturalist will not apply to all observations from the region currently referred to as A. gibbosa. Ancula pacifica usually ranges north to northern California, but in warm water years can be found as far north as Oregon and Washington, where it overlaps in distribution with A. gibbosa."

You may want to take a look at your Ancula observations to make sure they're IDd correctly, but there's a good chance Jeff and others already tidied up the names for you.

Softcover edition of Behrens et al, Nudibranchs and Sea Slugs of the Eastern Pacific, 2022 is available now at or Amazon.

Posted on March 09, 2023 03:53 AM by anudibranchmom anudibranchmom | 0 comments | Leave a comment

March 04, 2023

Eastern Pacific Nudibranch News: Catriona spadix Reinstated (previously Southern form of Catriona columbiana)

You don't have to do anything! I changed it automatically for you based on range. ;-)

Catriona spadix is now its own species; it was most recently called the southern form of Catriona columbiana. A reproduction of the lovely 1905 color illustration by Olive MacFarland (finally published 61 years later, in 1966) of 'Cratena spadix' appears on the acknowledgments page of Behrens et al, "Nudibranchs and Sea Slugs of the Eastern Pacific," 2022. Photographs of both species are on page 146.

To quote Dave Behrens in a 2002 SlugSite post: "C. columbiana has had a bouncy taxonomic past."

Mercifully, it's relatively easy to distinguish these two species, both by appearance and range. Catriona spadix has red-orange oral tentacles, whereas Catriona columbiana has white oral tentacles. (Both have red-orange rhinophores.) Range also helps, although they may overlap in Oregon. Catriona columbiana occurs from the Sea of Japan to Alaska to Cape Arago, Oregon, and Catriona spadix occurs from Cape Arago, Oregon to San Diego, California.

Here's a link to the paper:

Posted on March 04, 2023 01:28 AM by anudibranchmom anudibranchmom | 0 comments | Leave a comment

January 17, 2023

Eastern Pacific Nudibranch News - Revisions in Genus Coryphella

Pacific Northwest nudibranch observers: Two new name changes, but you don't have to do anything.

1) Predaceous Aeolis (Himatina trophina) has a new genus name once again. The current name is now Coryphella trophina. I have retained the old common name (Predaceous Aeolis) for clarity.

2) Coryphella pseudoverrucosa is no longer a separate species. It is now considered a junior subjective synonym of Coryphella verrucosa (Red-fingered Aeolis).

In both cases, you do not have to go back and rename your Observations, it happened automatically when I did the taxon swaps.

Citation: Ekimova, I.; Valdés, Á.; Malaquias, M. A. E.; Rauch, C.; Chichvarkhin, A.; Mikhlina, A.; Antokhina, T.; Chichvarkhina, O.; Schepetov, D. (2022). High-level taxonomic splitting in allopatric taxa causes confusion downstream: a revision of the nudibranch family Сoryphellidae. Zoological Journal of the Linnean Society. , available online at

Posted on January 17, 2023 03:33 AM by anudibranchmom anudibranchmom | 0 comments | Leave a comment

November 11, 2022

Are you an iNat Maverick? Time to Marie Condo your IDs.

End-of-Year Cleanup Time. 'Tis the annual season to find out how badly you have been misidentifying things. I just Marie Condo'd my identifications, and despite the repeated eyerolling at my own goofs ("How did I identify it as THAT?"), I feel much better that at least they're now corrected.

Want to do your own ID cleanse? Paste in the following, then cut and substitute anudibranchmom for your own user name:

Now won't you feel better?


Posted on November 11, 2022 08:19 PM by anudibranchmom anudibranchmom | 4 comments | Leave a comment