Fodonyx (meaning "digging claw") is an extinct genus of rhynchosaur from the middle Triassic epoch of Devon in England.

[1] Its fossils (25 specimens) were discovered in Otter Sandstone Formation (late Anisian age) and were first assigned to Rhynchosaurus spenceri.

They form the classic rhynchosaurian beak, and there is evidence on the fossil showing that it was probably covered by a keratinous sheath.

The maxilla carries a massive tooth plate and has numerous foramina for nerves and blood vessels to reach the gums through.

The jugal is complex, with four branches, and forms the anterior and ventral margins of the lower temporal fenestra.

The dorsal branch forms a strong pillar behind the orbit, which has a more pronounced crest than other rhynchosaurs.

The parietals are fused and have a high narrow ridge dorsally, with lateral wings extending across the upper temporal fenestrae.

Small fragments of the hyoids are preserved, with a circular cross section and lateral striations.

The dorsal vertebrae have round centra which narrow noticeably towards the centre of the bone, and are deeply amphicoelous.

Neural arches are around 15 mm tall, with narrow pillars supporting the zygapophyses, and are attached by broad flat facets.

Each ungual bears a shallow groove along the sides, probably for locking the keratin sheath.

[1] Cladogram based on Ezcurra et al. (2016):[3] Noteosuchus Mesosuchus Howesia Eohyosaurus Rhynchosaurus Mariante rhynchosaur Stenaulorhynchus Langeronyx Bentonyx Fodonyx Isalorhynchus Teyumbaita Hyperodapedon