Helminths of the southwestern toad, Bufo Microscaphus , Woodhouse's toad, Bufo woodhousii (Bufonidae), and their hybrids from central Arizona

The gastrointestinal tracts, lungs and urinary bladders from 77 Bufo microscaphus , 61 Bufo woodhousii , and 8 of their hybrids were examined for helminthes. One species of trematode ( Glypthelmins quieta ), 1 species of cestode ( Distoichometra bufonis ), and 5 species of nematodes ( Aplectana incerta, A. itzocanensis, Rhabdias americanus, Physaloptera sp., and Physocephalus sp.) were found. The greatest prevalence (41%) and mean intensity (231.7) were recorded for Aplectana incerta in Bufo woodhousii . It appears hybrids harbor fewer parasites than either parent species.