“A recent paper by Suárez & Esteve (2021) concludes that taxa with enrolment types not associated with coadaptive structures were less constrained in the shape of the cephalon and were thus able to achieve greater disparity. The analysis presented in their paper is limited to a single disparity index, the sum of variances. Consideration of this index in the context of changes in sample size and sum of ranges, a disparity index which reflects the overall breadth of morphospace occupation, refutes this interpretation. □ Trilobite, enrolment, disparity, evolvability.” read this comment