Figure 1. Optimizations of web presence/absence (A), and nine web architectures with web absence coded as missing data (B) under the corHMM ER model.

CorHMM ER model optimization of (A) web presence/absence, showing that webs are primitive for spiders, and (B) optimization of nine web architectures with web absence coded as missing data, showing evidence for an ancient origin of the orb web.