( This ( ( seems ( to ( indicate ( ( ( ( that ( ( ( the ( oldest ancestors ) ) ( of ( these creatures ) ) ) ( possessed endoskeletons ) ) ) , ) and ) ( that ( exoskeletons ( evolved later ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ seems) (S (VP (TO to) (VP (VB indicate) (SBAR (SBAR (IN that) (S (NP (NP (DT the) (JJS oldest) (NNS ancestors)) (PP (IN of) (NP (DT these) (NNS creatures)))) (VP (VBD possessed) (NP (NNS endoskeletons))))) (, ,) (CC and) (SBAR (IN that) (S (NP (NNS exoskeletons)) (VP (VBD evolved) (ADVP (RB later)))))))))) (. .)))
This seems to indicate that the oldest ancestors of these creatures possessed endoskeletons, and that exoskeletons evolved later.
(ROOT (S (NP (NNS Humans)) (VP (VBP possess) (NP (DT a) (PRN (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-)) (NN endoskeleton))) (. .)))