Fig. 1

Phylogeny of the sigmodontine rodents. L1 and B1 activity displayed on the phylogeny shows that L1 extinction preceded that of B1. The phylogeny is based on Schenk et al. [57]. Taxa are the genera sampled; tribes are indicated on the right side of the taxa. Eight of the nine tribes and 12 of the 14 genera sampled by Rinehart et al. [52] are shown. L1 and B1 activity of each taxon is demonstrated by color: black, active L1 and B1; deep blue, active L1 and inactive B1; deep red, inactive L1 and inactive B1; light blue, L1 activity cannot be inferred; and, light red, L1 and B1 can be inferred to be inactive. “+” corresponds to active L1 and B1 and “o” corresponds to inactive L1 and B1