auriformis Suter, 1909
A new slug continues to make its presence known in California waters three years after it was first reported back in 1995. Its name is Philine auriformis, and it was introduced from New Zealand. It looks very much like Philine bakeri (species # 23 in Pacific Coast Nudibranchs, Behrens 1991), up to 1 1/2 inches in length, except that when it stretches out, giving the appearance of a fat white Navanax. It occurs in shallow water up to intertidal, on mud, sand and shell debris bottoms. Gosliner (1995) reported it from south San Francisco Bay where it appears to be one of the most numerous species on the bay's bottom. It is a voracious carnivore feeding on small clams and worms. The egg masses are large white spirals, and it apparently likes California, successfully reproducing for several years now. In Bodega Bay as many as 18 per square meter have been observed. It is also been found in Elkhorn Slough, Morro Bay, Monterey Bay, and as far south as San Diego. Our colleagues are interested in tracking its expansion because of the potential damage to balanced populations this new introduction brings.
For an excellent discussion on the biology of Philine auriformis, please see a recent posting on Dr. Bill Rudman's Sea Slug Forum!
David W. Behrens
Pacific Coast Nudibranchs
Send Dave mail at email@example.com