Paradise Reserve, Santa Barbara, Californika

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The banana slug of the Santa Ynez Mountain range

Information provided by
Dr. John Pearse, Professor Emeritus, Ecology and Evolutionary Biology, University of California, Santa Cruz,

banana slug




At Paradise Reserve, the banana slugs occur around the Cielo creek.  During Fall, they congregate around a spring in the cielo creek.  The rest of the creek dries in the Fall.  In the rainy season, the slugs disperse away from the spring, and move to the oak woodland and other parts of the creek.


The banana slugs found in Santa Barbara are of a species called Ariolimax stramineus, An interesting thing about the species is that it occurs in the Santa Lucia Mountains of Monterey County, from Carmel Valley south to the Monterey-San Luis Obispo County line, and then again in Santa Barbara and western Ventura counties, but not in San Luis Obispo County.

Ariolimax stramineus forms two distinct clades-- the Monterey County and Santa Barbara-Ventura Counties clades, so they have been separated for some time. Each of those clades have at least two subclades that are separated geographically. Samples from Santa Rosa Island are clustered with those from southern Monterey County. Perhaps they reached the islands rafting on logs from Monterey.

The figures below show 2 DNA phylogenies for the banana slugs of the genus Arilomax.

199 Ariolimax-samples + Hemphilia
Sequencing data CO1 – 16S – CytB
Mega3 : NJ / Jukes-Cantor / complete deletion / 100 bootstraps



CO1 – 16S – CytB : stramineus – clade