Hi Ken,
Gilas and Beadeds are cousins but have many differences in taxonimy, color,size, and so forth. Heloderma horridum gets about 3times larger than H.suspectum. H.horridum has larger thicker scales and a much longer semi prehesiled tail than the former. There are three orrifaces(wich disperse venom)in the mouth of H.suspectum,while H.horridum has just one. Both have groves in their teeth and a pit at the base of each tooth for venom dispersal.If you would like to learn more Check out The Bilology of Gila Monsters And Beaded Lizards by Dan Beck. You can purchase it from U.C.press from my web site.
Good Luck
HorridumAngeli

www.Helodermahorridum.com