Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
testūdĭnĕātus and testūdĭnātus, a, um, adj. [testudo, II. B.], arched, vaulted: tectum, Col. 12, 15; Vitr. 2, 1 med.: cavaedium, id. 6, 3.