The sharp change in slope of the ultrahigh-energy cosmic ray spectrum around
10^{9.6} GeV (the ankle), combined with evidence of a light but extragalactic
component near and below the ankle which evolves to intermediate/heavy
composition above, has proved exceedingly challenging to understand
theoretically. Recently, we introduced a very general model in which, for a
range of source conditions, photo-disintegration of ultrahigh-energy nuclei in
the region surrounding the accelerator naturally accounts for the observed
spectrum and composition of the entire extragalactic component, which dominates
above about 10^{8.5} GeV. In this communication we review the generalities of
the model and show that starburst galaxies provide a compelling source example.Comment: Based on talk given at the European Physical Society Conference on
High Energy Physics (EPS-HEP), Venice, Italy 5-12 July 2017. To be published
in the Conference Proceeding
