What’s interesting about this is that the second toe claw in Cariama is slightly enlarged relative to those of digits III and IV (as you can see from the very poor accompanying photos).    From Wordnik.com.  [More on phorusrhacids: the biggest, the fastest, the mostest out-of-placest] Reference

Red-legged seriema (Cariama cristata) of the Cerrado grasslands of central Brazil.    From Wordnik.com.  [Cerrado] Reference

Some of the most distinctive birds in the hotspot include two very large species, the rhea (Rhea americana) and the red-legged seriema (Cariama cristata), neither of which are endemic.    From Wordnik.com.  [Biological diversity in the Cerrado] Reference

Tonni & Tambussi (1988) described the foot morphology of the Miocene psilopterine Psilopterus and showed that its foot claws were nearly identical to those of the living seriema Cariama cristata.    From Wordnik.com.  [More on phorusrhacids: the biggest, the fastest, the mostest out-of-placest] Reference