( ( ( oldest ( know reptiles ) ) ; ) ( ( ( ( evolved ( during ( ( ( the ( Early Pennsylvanian ) ) ; ) ( ancestors ( of ( all ( other reptiles ) ) ) ) ) ) ) , ) thus ) ( commonly ( called ( the ( stem reptiles ) ) ) ) ) )
(ROOT (S (S (NP (JJS oldest)) (VP (VBP know) (NP (NNS reptiles)))) (: ;) (S (S (VP (VBN evolved) (PP (IN during) (NP (NP (DT the) (NNP Early) (NNP Pennsylvanian)) (: ;) (NP (NP (NNS ancestors)) (PP (IN of) (NP (DT all) (JJ other) (NNS reptiles)))))) (, ,) (ADVP (RB thus)))) (ADVP (RB commonly)) (VP (VBN called) (NP (DT the) (NN stem) (NNS reptiles))))))
oldest know reptiles; evolved during the Early Pennsylvanian; ancestors of all other reptiles, thus commonly called the stem reptiles
(ROOT (S (NP (NNP Birds)) (VP (VBD evolved) (PP (IN from) (NP (JJ reptile) (NNS ancestors)))) (. .)))