( ( ( ( Reptiles ( are ( tetrapod vertebrates ) ) ) ; ) ( they ( ( ( have ( four limbs ) ) or ) ( evolved ( from ( a ( four-limbed ancestor ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNS Reptiles)) (VP (VBP are) (VP (VBN tetrapod) (NP (NNS vertebrates))))) (: ;) (S (NP (PRP they)) (VP (VP (VBP have) (NP (CD four) (NNS limbs))) (CC or) (VP (VBD evolved) (PP (IN from) (NP (DT a) (JJ four-limbed) (NN ancestor)))))) (. .)))
Reptiles are tetrapod vertebrates; they have four limbs or evolved from a four-limbed ancestor.
(ROOT (S (NP (NNS Caecillians)) (VP (VBD evolved) (PP (IN from) (NP (JJ tetrapod) (NNS ancestors)))) (. .)))