 Many teeth are widest at their <unk> 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 . 
