( Synapsids ( ( were ( the ( first ( tetrapods ( to ( evolve ( ( differentiated ( , ( or ( heterodont , ) ) ) ) teeth ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Synapsids)) (VP (VBD were) (NP (DT the) (JJ first) (NNS tetrapods) (S (VP (TO to) (VP (VB evolve) (NP (ADJP (JJ differentiated) (, ,) (CC or) (JJ heterodont) (, ,)) (NNS teeth))))))) (. .)))
Synapsids were the first tetrapods to evolve differentiated, or heterodont, teeth.
(ROOT (S (NP (NNS Caecillians)) (VP (VBD evolved) (PP (IN from) (NP (JJ tetrapod) (NNS ancestors)))) (. .)))