Lyreidus tridentatus is a species of crab in the family Raninidae.
This species as an unusual carapace in that it is longer than it is wide. Males grow to about 5.2 cm long and 1.3 cm wide. Females grow to 3 cm wide and about 4.9 cm long. They have a reddish to reddish-brown body, with a retuculated pattern. The pereopods are pale-pinkish tan colour.