GODDARD ET AL.: EL NINO IMPACT ON HETEROBRANCH SEA SLUG RANGES 117 
Figure 2. Nudibranch sea slugs found at new northern localities in the Northeastern Pacific Ocean, 2015-2017. 
A Doris cf. pickensi, Morro Bay, California, 25 May 2016. Image by CH. B Doriopsilla albopunctata. Whiskey Creek, 
Curry Co., Oregon, 19 May 2017. Image by NT. C Doriopsilla fulva, Netarts Bay, Oregon, 16 July 2016. Image by Todd 
Cliff. D Hermissenda opalescens, Box Canyon, Neah Bay, Washington, 20 August 2015. Image by Doug Miller. 
Remarks: Lindsay and Valdes (2016) reinstated//, opalescens as distinct from//, crassicornis 
(Eschscholtz, 1831) and showed that externally H. opalescens can be distinguished in the North¬ 
east Pacific Ocean from H. crassicornis by the lack of white stripes on the cerata of the former. 
The two color forms have long been recognized in field guides to nudibranchs from the northeast¬ 
ern Pacific Ocean (e.g., Behrens 1980; McDonald andNybakken 1980). Lindsay and Valdes (2016, 
pp. 7 and 8) described the range of H. opalescens as extending from “the Sea of Cortez through 
Oregon,” but in their conclusions described H. opalescens as ranging north only to Bodega Bay, 
apparently using a more conservative standard based solely on specimens they sequenced. They 
then stated that H. crassicornis and H. opalescens overlap in range “between Point Reyes and 
