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] A Field Guide to Mesozoic Birds and Other Winged Dinosaurs ... [PAR] Te first Archaeopteryx fossil, and in fact the first Mesozoic bird ..... water, negating 
the need to climb up trees, and the wing claws were greatly reduced .... not 
considered birds because they were thought to fall just outside the clade ...... 
indicates that the tail frond grew large first, & that the wings developed more 
slowly, likely.