The generic name is derived from Latin draco, "dragon", and Ancient Greek ὄνυξ, onyx, "claw".

The holotype, ML 357, a partial skeleton lacking the skull, consists of two maxillary teeth, three caudal centra, one chevron, a distal epiphysis of right humerus, one manual phalanx, three manual unguals, a distal epiphysis of the right femur, the proximal and distal epiphyses of the tibia and fibula, an astragalus, a calcanaeum, three tarsals, four metatarsals and pedal phalanges.

It was in 1991 found at Vale de Frades by Carlos Anunciação of the Museu da Lourinhã, in layers of the Bombarral Unit dating to the Tithonian.

Histology shows that the holotype specimen reached skeletally maturity after the age between 27 and 31 years old.

[3] According to Mateus and Antunes (2001), Draconyx loureiroi is a member of the Iguanodontia, more specifically the Camptosauridae, based on the maxillary teeth, which have a strong vertical primary ridge on the distal side of the labial crown, and the femur, which is curved and has a prominent lesser trochanter.