Lets start with some published definitions.
Dinosaur bones occur in sediments that were deposited during the Mesozoic Era, the so-called era of middle animals, also known as the age of reptiles. Considering that the earth is 5.5 billion years old, this discrepancy is less than half of one percent. There were mammals, fish, birds and other animals during the Mesozoic Era which also left fossils. These fossils will not be included. A dinosaur was terrestrial.