William Daniel Conybeare FRS (7 June 1787 – 12 August 1857), dean of
Llandaff, was an English geologist, palaeontologist and clergyman. He is probably best known for his ground-breaking work on marine reptile fossils in the 1820s, including important papers for the
Geological Society of London on
ichthyosaur anatomy and the first published scientific description of a
plesiosaur.