I've been reading both the Typhon Pact and Cold Equations series of late and I've become interested in the Gorn as a species. Specifically their evolutionary ancestors. Judging by the descriptions throughout the Trek-verse I'm certain they evolved from something akin to the Monitor Lizards of Earth. Of the extant lizards here on Earth monitors are intelligent carnivores that are quite versatile when it comes to survival. Given the Gorn Archosaurs are carnivorous, fairly intelligent, and possess sharp senses I'm certain an alien version of the varanid (scientific name of the family that includes monitor lizards) were the earliest ancestors of the Gorn.