One thing that came up in the discussion thread on Dark Mirror that I started up yesterday was the topic of multiple sapient species existing on a single world. (Cetaceans came up initially, but as the discussion progressed all sorts of reasonably intelligent, communicative, even tool-using species from elephants to corvids to cephalopods came up. What examples of a world with more than one indigenous sapient species are there in the Trkeverse? Valakis has the Valakians and Menk in the Enterprise episode "Dear Doctor", along with the Xindi from the same series. I find the Xindi more plausible, actually--the five, originally six, sapient species of Xindus would each have evolved in very different ecological niches and would have been less likely to be outcompeted by others, while the Valakians and Menk are very closely related compete in the same areas. (I'd have bet that the Menk would be absorbed into the Valakians, on the model of the Neanderthals into the Homo sapiens sapiens population.) Earth, as Star Trek IV established, is also one of these worlds, humans and humpback whales co-existing for centuries until the latter species' 21st century extinction. What am I missing?