Plains Spadefoot {Spea [=Scaphiopus] bombifrons) 



Description: Adults are colored gray or brown with darker mottling on the back and a white belly. 

 Some individuals have indistinct longitudinal streaking. The pupils of the Plains Spadefoot are 

 vertically elliptical and there is a high, hard lump between the eyes. Its skin is less warty than 

 true toads. The adult has a single tubercle on the hind feet and has a body length of less than 

 2.5". 



Eggs and Tadpoles. Oval egg masses of 10-250 eggs are attached to underwater plants or 

 debris. Tadpoles are mottled sooty and olive-yellow above and paler below with gold metallic 

 flecking over all; iris is gold. Older tadpoles, from the two-legged stage on, show a small 

 black tubercle on the hind feet. 



Similar species: Other Montana frogs and toads have round or horizontally elliptical pupils. 



Habitat and Habits: Adults are found in grassland and sagebrush areas, particularly in areas with 

 sandy or loose soil (Wheeler and Wheeler 1966, Hammerson 1982a, Baxter and Stone 1985). 

 Except during breeding, they are seldom found in the water. They are primarily nocturnal and 

 emerge from their burrows only following heavy rains. They breed in shallow temporary 

 pools usually following heavy spring or summer rains (Hammerson 1982a). Males call loudly, 

 with groups being heard for up to a mile. Eggs hatch after 2-3 days and tadpoles transform in 

 6-10 weeks (Wheeler and Wheeler 1966, Hammerson 1982a). In 1998, 10+ adults were 

 heard calling at one site (Miles Creek, Custer County) during a rainy night on 30 May 

 (Appendix 2). In 1995, tadpoles at several stages of development (legless to 4-legged 

 metamorphs) were found on 3 surveys between 29 June and 1 July in Carbon County 

 (Appendix 3a and 3b). 



Surveying: Adults may be easily found by using their calls for identification when breeding at 

 night or by "road hunting" on warm, rainy nights. Calling normally takes place only when the 

 temperature is >50 F (Hammerson 1982a). Tadpoles are seen in ponds during the day and 

 can be sampled with a dipnet. Surveying is complicated by the long time periods which this 

 species spends underground, especially during droughts. 



Status: The Plains Spadefoot was found at a single location in Custer County during our 1998 

 surveys (Appendix 2), and breeding was documented at 3 sites in 1995 in Carbon County 

 (Appendix 3b). There were two additional reports from 1998 (in Treasure and Yellowstone 

 counties). Despite few reports, spadefoots have been reported over the years from 

 throughout the Miles City District, BLM. It is apparently locally common in eastern Montana 

 (such as southern Carbon County), but there are large gaps in the known range. It should be 

 watched for in prairie or shrub-steppe habitat, especially following late-spring and early- 

 summer rains. Any located should be well-documented. 



Montana Natural Heritage Program rank: G5 S4? 



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