About Limacia mcdonaldi Uribe, Sepúlveda, Goddard & Á.Valdés, 2017
Before Limacia mcdonaldi was formally described in 2017, observers frequently discussed the possibility that what was classified as Limacia cockerelli actually included two or more separate species. At that time, the different forms were distinguished from one another by the color of their rhinophores and gills: the red form was recognized as L. cockerelli, while the orange form was what is now named L. mcdonaldi. The type locality of Limacia mcdonaldi is White's Point, Palos Verdes, California. The species' geographic range extends from Salt Point in Sonoma County, California, south to Bahia de los Angeles, Baja California. Its range overlaps with the range of Limacia cockerelli along nearly 850 km of the California coast, between San Diego and Salt Point. Between 2014 and 2016, L. mcdonaldi became quite common in the Monterey Bay and San Francisco areas. This increase in abundance coincided with elevated sea water temperatures during that period, caused by an El Niño event.
