The first part of the post title is a classic question, the second because the link to Lantz's FanDex is dead. If anyone can point me in the right direction, I'll update it.

I was reminded of the Dex partly by this post
at Sons of Twilight on the Epic warhound, because Lantz's list has a warhound and because there's a great admech / titan legion list for Epic: Armageddon here at Tactical Command - with the early titan weapons and upgrades.

On the subject of the adeptus mechanicus, how much of the mix of concepts do you think could come via the Morlocks, first seen in H. G. Wells' The Time Machine?

There's been a lot of Morlock-related posting recently, including last week's post for Fate at Fate SF, yesterday's at Hereticwerks with 20 Morlock NPCS for Labyrinth Lord and compatible rulesets and the Mog session reports at Aeons & Augauries, possibly more.

John's describes the Morlocks as 'machine-tending subterraneans', and the cannibalism is mentioned too. We do know 40K has been inspired by various sources, even if now it may be eating its own tail - cf. those centurions centurions, nearly
Russian doll marines.

According to the summary at the Lexicanum, the Dark Age of Technology leads to lack of maintenance on Mars. Radiation upsets the biosphere, causing plague, mutation and cannibalism. Then the cult appears, technology is remastered and the shelters rebuilt, sites for the people to huddle and regroup. Or maybe the new novels have rewritten this?

Similar maybe, but if Wells was an influence, I'd imagine GW would have taken the lot, the Eloi too, at least the Eloi-Morlock dichotomy. It may be that GW just picked up the ideas second- or third-hand, via Metropolis, weird pulp and the Doomsday-type B-movie.

Edit: What am I thinking? There's a dichotomy of sorts with the Imperium, relative parity based on distinct structure, parallel religion and the admech providing and maintaining Imperial tech, the actual throne too of course, life support for the Emperor. Still, this could also reflect other possible sources, like Dune's Spacing Guild. More re Dune here.

So much material, some of it very suggestive. Can all of the value survive six editions..?

Also, has there ever been backwards time travel in modern 40K? Maybe that's a future lifeline. (I have a few related thoughts here on other ages and here on cross-pollination.)

A more general question: could the Morlocks have used the time machine while they held it? In the 'expanded universe' of public domain sci-fi, there is Morlock Night. Maybe there's an variant time stream out there in which they dominate, or things are very dark?

Finally, turning other admech themes on to the Morlocks, they seem good candidates for transhumanism by augmentation, and a machine god or organic machine cult, which could get you to the kind of dark mechanical forms seen in the last post at Eye of Error.

For more on classic public domain sci-fi, have a read of this reflection on Arthur Machen.