Many teeth are widest at their midsections and narrow closer to the jaws, giving them the appearance of a teardrop. Teardrop-shaped teeth are unique to "Dimetrodon" and other closely related sphenacodontids, and help distinguish them from other early synapsids. As in many other early synapsids, the teeth of most "Dimetrodon" species are serrated at their edges. The serrations of "Dimetrodon" teeth were so fine that they resembled tiny cracks. The dinosaur "Albertosaurus" had similarly crack-like serrations, but, at the base of each serration was a round void, which would have functioned to distribute force over a larger surface area and prevent the stresses of feeding from causing the crack to spread through the tooth. Unlike "Albertosaurus", "Dimetrodon" teeth lacked adaptations that would stop cracks from forming at their serrations. The teeth of "D. teutonis" lack serrations, but still have sharp edges.