Spinosaurus Fossil (IMAGE) PeerJ Caption Comfortably leaning on a thumb's nail, the new Spinosaurus fossil is only 21 mm long. The flat palmar side and the feebly curved profile of this ungual bone are highly diagnostic and show the same adaptation seen in the foot of adult specimens. Credit G. Bindellini Usage Restrictions CC BY 4.0 License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.