The body of the tadpole is broadest just behind the eyes, tapering gradually towards the bottom of the tadpole and tapering sharply towards the top. It has a short snout, and a tail that is about 1 1/3 - 1 1/4 times the head-body length that has its greatest width near the midpoint. The dorsal fin originates posteriorly on the body. The eyes are close together and well up on the head, and the anus is medial, emerging in the base of the ventral fin. The spiracle is low on the left side, belove the lateral axis of the body (Stebbins 1962).
Similar species: S. multiplicata can be easily mistaken for Spea bombifrons. Newly metamorphosed toadlets which have been in preservative for long periods of time are difficult to distinguish. S. multiplicata lacks a frontal boss, unlike adult S. bombifrons, but these two species frequently hybridize making this characteristic unreliable at times (Simovich 1994). S. multiplicata can be distinguished from Scaphiopus couchii by coloration: brown or dark grey with red-tipped tubercles in S. multiplicata, vs. greenish-yellow dorsum with dark mottling in Scaphiopus couchii (Degenhardt et al. 1996).
- Brown, H. A. (1976). ''The status of California and Arizona populations of the Western Spadefoot Toads (genus Scaphiopus).'' Los Angeles County Museum of Natural History, Contributions in Science, 286, 1-15.
- Conant, R. and Collins, J. T. (1991). A Field Guide to Reptiles and Amphibians: Eastern/Central North America. Houghton Mifflin, Boston.
- Degenhardt, W.G., Painter, C.W., and Price, A.H. (1996). Amphibians and Reptiles of New Mexico. University of New Mexico Press, Albuquerque.
- Sattler, P.W. (1980). ''Genetic relationships among selected species of North American Scaphiopus.'' Copeia, 1980(4), 605-610.
- Simovich, M. A. (1994). ''The dynamics of a spadefoot toad (Spea multiplicata and S. bombifrons) hybridization system.'' Herpetology of North American Deserts. P. R. Brown and J. W. Wright, eds., Special Publication No. 5, Southwestern Herpetologists Society, Los Angeles.
- Smith, H. M. (1978). A Guide to Field Identification: Amphibians of North America. Golden Press, New York.
- Stebbins, R. C. (1962). Amphibians of Western North America. University of California Press, Berkeley.
- Tanner, W. W. (1989). ''Status of Spea stagnalis Cope (1875), Spea intermontanus Cope (1889), and a systematic review of Spea hammondii Baird (1839) (Amphibia: Anura).'' Great Basin Naturalist, 49, 503-510.