Reptile
From Memory Alpha, the free Star Trek reference.
Reptiles are a group of cold-blooded vertebrates.
The self-aware machine Vaal from the planet Gamma Trianguli VI resembled a giant reptile with massive fangs and a horn on its nose. (TOS: "The Apple")
A similar reptile was depicted on the communicators used by the terrorists who tried to steal trilithium resin from the USS Enterprise-D in 2369 (TNG: "Starship Mine")
The tribble homeworld of Iota Geminorum IV is home to a large number of reptiles. They are instrumental in keeping the tribble population in check. (DS9: "The Nagus")
