sentences:  In postcanine Megadontia specimens, the cross sectional area is on average much larger than modern hominids which implies greater shear stress resistance.Some important genes involved in the development and regulation of tooth formation include BMP4, FGF8, and homeobox genes such as MSX1, PAX9, PITX2, SHOX2, Barx1, and Shh to name a few.Research suggests that homeobox genes are mainly responsible for much of the variance in tooth morphogenesis observed in fossilized hominids.