Assertion: eye's cell | /r/CapableOf | diverge in animal evolution
Facets:
value: earlier
type: TEMPORAL
Source sentences:
text: It is thought that ciliary and rhabdomeric photoreceptor cells are descended from a single ancestral cell type, though there is some ongoing debate as to whether the Urbilaterian possessed (a) a ciliary precursor type from which both are derived, (b) a dual ciliary or rhabdomeric precursor that later diverged into two types, or (c) both ciliary and rhabdomeric cells that had already diverged earlier in animal evolution.