The 1st claw of the Utahraptor was thought to be a rib--they grew 'em big in this period, from Latin for "chalk"
[DOC] [TLE] Free Flashcards about NATURAL HISTORY - StudyStack [PAR] THE 1ST CLAW OF THE UTAHRAPTOR WAS THOUGHT TO BE A RIB...THEY 
GREW 'EM BIG IN THIS PERIOD, FROM LATIN FOR "CHALK", CRETACEOUS.