Fine structure in the α decay of 22190Th, populating excited states in 21788Ra, was studied using αγ-coincidence spectroscopy. Two α-decay branches from 221Th have been newly observed, with Eα(keV)[bα(%)]=7951(8)[0.14(3)] and 8247(3)[1.51(12)], together with three previously known branches. Also, two new states in 217Ra were identified at E = 177 and 227 keV. The ground-state configurations of the odd-A, N = 131 transitional isotones above 208Pb are interpreted from their α-decay fine structure systematics and considered in terms of predictions using spherical shell and reflection-asymmetric models.