It lacked the ability to pull its head into its shell , had a long neck , and had a long , spiked tail ending in a club . While this body form is similar to that of ankylosaurs , it resulted from convergent evolution .
They did lack the ability to pull their heads into their shell ( and they had a long neck ) , and ( `` Odontochelys '' ) had a long , spiked tail ending in a club , a body form similar to that of ankylosaurs , resulting from convergent evolution .