 Aetosaur remains have been found since the early 19th century , although the very first remains that were described were mistaken for fish scales . Aetosaurs were later recognized as crocodile relatives , with early paleontologists considering them to be semiaquatic scavengers . They are now considered to have been entirely terrestrial animals . Some forms have characteristics that may have been adaptations to digging for food . There is also evidence that some if not all aetosaurs made nests . 
