Lycaenops (‘wolf face’) had a long, narrow skull with doglike, pointed canine teeth in the upper and lower jaw. It weighed about 15 kg and fed on smaller reptiles and dicynodonts like Robertia.

Lycaenops ran like a mammal, with its long limbs straight under the body (unlike the sail-backed Dimetrodon, for example, whose legs stuck out to the side). This enabled Lycaenops to outrun its prey.

Lycaenops is more closely related than Robertia to the mammals.