COAST RANGE CORRIDOR IN CALIFORNIA 



173 



Madro-Tertiary Species 



Species of lizards and an anuran illustrate best the relationship of 

 the corridor to Madro-Tertiary elements moving in from Mexican 

 centers of origin. Southern mesic elements of the Madro-Tertiary 

 complex invaded the corridor from the south end, but in a variable 

 manner. The western spadefoot, Scaphiopus hanimondii, appears to 

 have "flooded" the corridor (Fig. 9) and the adjacent valley to its 

 northern end, meanwhile developing a wide disjunction in the lower 

 Colorado Valley. A related, northern species in the Great Basin 

 appears to be in the process of invading the San Joaquin Valley via 

 Walker Pass. Patterns somewhat similar to that of S. hammondii 

 occur in Bujo microscaphns and Ilyla arenicolor, without the pres- 

 ence of a related Great Basin species. This suggests that species ap- 



WESTERN SPADEFOOT 



SCAPHIOPUS 

 . j\ HAMMONDI 

 |L GREAT BASIN 

 •4^ SPADEFOOT 

 \^ S. INTERMONTANUS 



7 

 / 



Fig. 9. Distribution of western spadefoot, Scaphiopus hammondii, and 

 Great Basin spadefoot, Scaphiopus intermontanus. Former now has 

 disjunct distribution in Californias and areas to east. Apparently 5. 

 intermontanus has recently invaded western Sierran foothills through 

 mountain passes. 



