Leviathan was not referenced in the Bible as a dinosaur - Leviathan, serpent and Satan are used interchangable. Most people understand Leviathan of Job 41 to be a whale.
Both the behemoth and leviathan are given as examples in Job of evil that only God can overcome.
Word Origin & History
late 14c., huge biblical beast (Job xl.15), from L. behemoth , from Heb. b'hemoth, usually taken as plural of intensity of b'hemah "beast." But the Heb. word is perhaps a folk etymology of Egyptian pehemau , lit. "water-ox," the name for the hippopotamus.
Online Etymology Dictionary, © 2010 Douglas Harper
(Job 40:15-24). Some have supposed this to be an Egyptian word meaning a "water-ox." The Revised Version has here in the margin "hippopotamus," which is probably the correct rendering of the word. The word occurs frequently in Scripture, but, except here, always as a common name, and translated "beast" or "cattle." http://dictionary.reference.com/browse/behemoth
So we have the hippo and the whale - neither of which are dinosaurs.