Goniodorididae, H. Adams & A. Adams, 1854

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 : 110-111

Goniodorididae

Okenia angelensis Lance, 1966 . Miwok Beach, Sonoma Co., California, 1 specimen, 5 mm long, low rocky intertidal, 27 May 2017, observed by Colby Davidson ( Fig. 1A ) (Hollis Bewley, personal communication to JS, 5 June 2017) to Punta Rosarito, Baja California, Mexico (Goddard and Hermosillo 2008); Bahía de los Ángeles, Baja California ( Lance 1966) and Chile ( Muñoz et al. 1996; Schrödl 1996).

Previous northernmost locality: San Francisco Bay , California ( Lance 1966) .

Remarks: The new record is also significant for its location on the outer coast, outside the seasonal warm water refugium of San Francisco Bay.

Onchidorididae

Acanthodoris rhodoceras Cockerell in Cockerell and Eliot, 1905. Chup Point, Barkley Sound, Vancouver Island, British Columbia, 1 specimen, 12 m depth, 21 May 2018 ( Fig. 1B ) found by Kathy Johnson (P. Mieras, personal communication to JG, 2 June 2018) to Bahía Tortugas, Baja California, Mexico ( Behrens 1991) and Bahía de los Ángeles, Baja California ( Bertsch 2014).

Previous northernmost locality: South side of Netarts Jetty in Netarts Bay , Oregon, 1 specimen 12 mm long, low intertidal, 17 June 2015 (observed by TP; see Maginnis 2016) .

Remarks: The identity of specimens collected in the 1960s from Alaska (including the Arctic Ocean) and Vancouver Island by J. McLean, and referred to as A. rhodoceras by Fahey and Valdés (2005), needs to be verified for the following reasons. First, except for the specimen recently found in Barkley Sound, there are no other records of A. rhodoceras from north of Oregon, including from Bernard (1970), Millen (1983, 1989), Lee and Foster (1985), Goddard et al. (1997), Goddard and Foster (2002), Lamb and Hanby (2005), and Fletcher (2013). Second, no other heterobranch gastropod is known to have a geographic distribution extending from the Arctic Ocean into the Gulf of California (see Behrens and Hermosillo 2005), especially as recent integrative systematic studies have shown that nudibranchs from the Northeast Pacific Ocean once considered to have broad geographic ranges are actually complexes of species with more limited, but overlapping ranges (e.g., Lindsay et al. 2016; Lindsay and Valdés 2016). Based on the records of A. pilosa (Abildgaard, 1789) and the closely related A. atrogriseata O’Donoghue, 1927 from the North Pacific, including the Aleutian Islands and south central Alaska (Lee and Foster 1985; Hallas et al. 2016), we think it likely the specimens collected by McLean in Alaska are either one or both of those species, a result likely to influence the biogeographic analyses conducted by Hallas et al. (2016), who relied on the distribution information given by Fahey and Valdés (2005) for A. rhodoceras , and who incorrectly showed it in their Figure 3 as being the only species of Acanthodoris present along most of the Pacific coast of Alaska.

Figures

Figure 3. Nudibranch sea slugs found at new northern localities in the Northeastern Pacific Ocean, 2015–2017. A Hermosita hakunamatata, La Bocana, Bahía de Magdalena, Baja California Sur, Mexico, 1 September 2015. Image by CH. B Phidiana hiltoni, Dillon Beach, California, 30 April 2017. Image by DM. C Taringa aivica, Mission Bay, San Diego, California, 14 June 2018. Image by CH. D Diaphoreolis lagunae, Whiskey Creek, Curry Co., Oregon, 19 May 2017 (grid squares 2 mm on a side). Image by NT.

FIGURE 1. Heterobranch sea slugs found at new northernmost localities in the Northeastern Pacific Ocean, 2015–2017. A Okenia angelensis, Miwok Beach, Sonoma Co., California, 27 May 2017. Image by Colby Davidson. B Acanthodoris rhodoceras, Chup Point, Barkley Sound, Vancouver Island, British Columbia, 21 May 2018. Image by Peter Mieras/subvisionproductions.com. C Polycera atra, Lemmens Inlet, Clayoquot Sound, Vancouver Island, British Columbia, 25 July 2015. Inset: tail. Images by Brandon Exner. D Thordisa rubescens, Santa Cruz Island, California, 1 November 2017. Image by Kenan Chan/Channel Islands National Park.