There are two distinct types of fangs among poisonous snakes: one type is located in the front, and second type is located in the back. The great question was whether two groups of venomous snakes developed their specialized fangs through separate evolutionary pathways. Though possible, this would present a more complicated evolutionary scenario.
Recently, a Netherlands research team examined 96 snake embryos in attempt to discern the truth. By examining jaw specimens with a scanning electron microscope and employing genetic analysis and 3D modeling, the scientists reached a fascinating conclusion: front fangs form in the back of the mouth. It appears both front and rear fangs start out in the rearward part of the jaw of snake embryos. During development, the front fangs move forward.
This finding indicates all venomous snakes share a common ancestor.
Further, it appears that the back portion of the tooth-forming area becomes developmentally detached from the rest of the mouth. The researchers suggest this configuration enabled the fangs to evolve separately from other teeth and in conjunction with the venom glands instead. This new arrangement may have sparked the diversification of snakes during the Cenozoic era, leading to the wide variety of snake species living today.