Duffinselache (Duffin's shark) is an extinct genus of basal shark elasmobranchii cartilaginous fish, known from a single species, Duffinselache holwellensis, collected from the Late Triassic (Rhaetian stage) of England. It was first named by Duffin in 1998 as a species of Polyacrodus. Plamen S. Andreev and Gilles Cuny in 2012 reassigned it to a new genus as its type species, Polyacrodus holwellensis.