Herbivore Dinosaur With Distinctive Thumb Spikes
Puzzle 11 of Running a Marathon Pack
Question is: Herbivore Dinosaur With Distinctive Thumb Spikes
and the answer is: IGUANODON
Word Meaning:
IGUANODON — Any large dinosaur of the genus †Iguanodon, of the Jurassic and Cretaceous periods.
Definitions from Wiktionary.