( ( ( The ancestors ) ( of tetrapods ) ) ( ( are ( to ( be ( found ( amongst ( ( the lobe-fins ) ( of ( the ( Devonian period ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS ancestors)) (PP (IN of) (NP (NNS tetrapods)))) (VP (VBP are) (S (VP (TO to) (VP (VB be) (VP (VBN found) (PP (IN amongst) (NP (NP (DT the) (NNS lobe-fins)) (PP (IN of) (NP (DT the) (NNP Devonian) (NN period)))))))))) (. .)))
The ancestors of tetrapods are to be found amongst the lobe-fins of the Devonian period.
(ROOT (S (NP (NNS Caecillians)) (VP (VBD evolved) (PP (IN from) (NP (JJ tetrapod) (NNS ancestors)))) (. .)))