Ensatina eschscholtzi xanthoptica

Distribution Map

 

 

Ensatina distribution
 

 

More xanthoptica photos

On the northern edge of xanthoptica distribution, it meets with oregonensis. There is a strong discontinuity between xanthoptica and oregonensis with few intergrades, and combined with molecular evidence, seems to indicate incipient species formation. (Wake, 1997)

During the Pleistocene when conditions were much wetter and colder, Stebbins, 1949, postulates that xanthoptica moved across the central valley of California to the foothills of the Sierra Nevada, a "transvalley leak." There it met populations of platensis and hybridization occurred. Brown, 1974, discovered that there is only an 8% hybridization in hybrid zones. Again, combined with molecular evidence, indicates another example of incipient species formation. (Wake, 1997)

To the south, xanthoptica abruptly intergrades with eschscholtzi near Watsonville, yet another example of incipient species formation.