Pleurobranchida

Goddard, Jeffrey H. R., Treneman, Nancy, Prestholdt, Tara, Hoover, Craig, Green, Brenna, Pence, William E., Mason, Douglas E., Dobry, Phillip, Sones, Jacqueline L., Sanford, Eric, Agarwal, Robin, McDonald, Gary R., Johnson, Rebecca F. & Gosliner, Terrence M., 2018, Heterobranch Sea Slug Range Shifts in the Northeast Pacific Ocean associated with the 2015 - 16 El Niño, Proceedings of the California Academy of Sciences 65 (3), pp. 107-131 : 110

Pleurobranchida

Berthella strongi ( MacFarland, 1966) . MacKerricker State Park , Mendocino Co., California, 1 specimen, low rocky intertidal, 4 July 2016 ( Pirrone 2016) to El Tomatal, Baja California, Mexico (Goddard and Green 2013; for image see <https://www.inaturalist.org/ observations/2957040>) .

Previous northernmost locality: Moss Beach, California ( Bertsch et al. 1972 [as Pleurobranchus strongi ]).

Additional northern localities: Salt Point State Park, Sonoma Co., California, 1 specimen, low intertidal, 9 May 2016 (observed by WP, DM, PD); Drake’s Estero , Point Reyes National Park , Marin Co. , California, 1 specimen, with an egg mass, next to its sponge prey Oscarella carmela , under a low intertidal cobble, 8 June 2016 (observed by JG) .

Remarks: Behrens (1998, 2004) reported B. strongi found by Mike Miller off of Nanaimo, British Columbia. No collection information, including date, or image were given, but M. Miller (personal communication to JG, 9 July 2016) dove there in 1998, and the record therefore may represent an ephemeral range extension driven by the strong 1997-98 El Niño event. However, it should be noted that this species has not been reported from north of California before or since, and without an image or specific collection data we consider this record unverified.