The only specimen of this species of dinosaur ever found was amere 3.5 metres long, was Cumnoria a fairly small ornithopod? The studies of this holotype at the MNH Oxford, reveal that this individual was probably juvenile, as indicative bones were unfused. An adult size remains purely speculation.
Cumnoria would have been a plant eater, walking on its hind legs and dropping on all fours to feed and amble.
The images used to illustrate these pages were drawn by Andrew Orkney and commissioned by Oxford Geology Group.
Andrew sets out the thinking behind his illustration:
Confusingly the Ornithischia, or 'bird hipped' dinosaurs are not the ancestors of birds, which are descended from Theropod Saurischian 'lizard hipped' dinosaurs. I find this distribution of bird-like features in dinosaurs, even those which are not ancestral to birds, intriguing and I have hence sought to emphasise the bird-like qualities in Cumnoria prestwichii, which belongs to Ornithischia. I have chosen to emphasise the beak, adding a soft pronounced knob atop the bill, and a growth below it. I intend this speculative feature to resemble the growths on the bill of a swan, which function as ornaments in sexual selection theory. I have also coated the animal in an exuberant pelage of proto-feathers, which may have been ubiquitous in dinosaurs, even occurring on basal dinosaurs.
Read H. Philip Powell's account of the discovery and scientific study of the Cumnoria prestwichii holotype fossil