Are the Gorn species and the Tamarian species related in the Star Trek Universe or other non-canon Star Trek references? I see some visual similarities between the two species.
Technically, probably yes.
(But we don't know for sure)
According to a TNG episode "The Chase" (season 6, episode 20), a lone ancient race of beings scouted our galaxy before there was any humanoid life there except for them. They are responsible for seeding various planets with their own DNA, out of which all humanoid life forms have developed. Therefore all of the races including Humans, Romulans, Cardassians, Klingons, etc. (and presumably Gorn and Tamarians) share a common ancestor.
I think it's safe to say the Tamarians were not meant to be updated versions of the Gorn, although they may be technically related in the sense Chahk mentioned (though I don't think this is clear--the Gorn look different enough from most "humanoids" that their basic body configuration might just be a case of convergent evolution). Aside from the fact that there seems to be almost no visual similarity between them in the pictures posted by Daft, the Gorn wiki article mentions that an updated version of a Gorn was shown in an Enterprise episode, "In a Mirror, Darkly Part II", and they weren't depicted as looking anything like the Tamarians: