Their teeth closely resemble those of modern sharks in the families Hexanchidae and Echinorhinidae, and they were tentatively classified in the Hexanchiformes when first described. However, more recent analyses indicate that they lack multiple layers of enameloid on their tooth crowns, something present in all modern sharks and many sharks that coexisted with Mcmurdodus. In addition, most divergence estimates for modern sharks are irreconcilable with the age of Mcmurdodus. For this reason, the Mcmurdontidae are now considered indeterminate chondrichthyans.[1][2][3][4]