That is a very lovely story, and indeed you're right. There are sources that predate Sitchin, namely "the flying saucer magazine..". Are you serious? The flying saucer..
Anyway, this is my humble view. First of all, a "flying saucer magazine" is not a source, it's not even an academic journal (meaning anyone can publish something without backing it up with proof). So before we get into reptilians and other kind of fantasy-world creatures like half man half anything, let's look at this in detail. I'm not gonna waste too much words on Sitchin, it's already been proven that Sitchin's translation of the tablets are not sound (meaning containing many errors) and that is normal, Mr Sitchin has never studies ancient languages so in fact it's better if he did not speak at all.. Many are the people who invited him for a debate (a friendly debate that is) but Mr Sitchin is literally hiding out somewhere, which already clearly indicates that his translations are fraudulous (and that's an understatement really).. Secondly, there is no proof whatsoever that annunaki even exist or existed. Show me archaeologucal evidence, show me a stone or just show me an image dating back to their times that proves annunaki exist. You can't, there are none.. Now Sumerian culture is a very old culture, dating back from thousands of years BC. It's the oldest culture we know of. The tablets found in Iran are not translated properly yet (that doesn't suprise anyone, noone speaks or writes sumerian nowadays, the language has died out). And this is exactly what one expects would happen,and it's always the same story, every time something is found and cannot (yet) be explained by "real" academics, people let thier imaginations run wild. Planet Nebiru, Reptilians, secret governement operations and a million other things.. These people are mostly dumb people (meaning people that do not read normal books to have a view of history) and there are a lot of them who just join in for the "mystery-kick".. After investigating a little more you probably find a majority of these so called "spreaders of the word" are linked with shady underground groups that suspect all kind of things. Secret conspiracies, governmenets holding back information, doomsday nearing ... Well it's not a crime to fabtasize, but it's not that polite to call that fantasy fact. Reality is, these tablets are mysterious (not for the reasons summed up here on this website, because these reasons are ridiculous really..). So those Ancient Aliens - Planet Nebiru - Sitchin followers and others following a strange path not based in reality, sorry for the bad news but annunaki never existed and probably never will (unless in your heads that is), planet nebiru is not a planet (not a real one that is) and all your fantasies and imagination was better kept inside your heads. By the way, I teach and study ancient languages in a college in europe, so take it from me, your theories are hallucinations. Anuway, no hard feelings, i just wanted to clear that up for you guys, so cheers and enjoy the newyear.