Music-Related-Requests and Mysterious Track

MYSTERIOUS TRACK:
So I've noticed a musical track that will sometimes play when exploring planets. I've only heard it on Toxic and Mutated planets so far, strangely, since most of the OST seems to be shared between a great many planet types, if not all of them.
Now, here's the odd thing. I've never heard this track before. Not in the old leaked experimental soundtracks, not in the current official soundtrack. I have no idea what it's called.

What I can say about it is that it sounds like the opening of Lava Exploration 1. Not the percussion - the droning background beat. Imagine that, but slower and synthier. It's very difficult to explain.

In fact, while repeatedly beaming down and up in hopes of getting a short snippet of the track for reference, I noticed at least one other track that I don't recall hearing on the official OST or ever before. Seems there are more than one.

I did finally manage to get a clip of it ingame. I shortened it to around 10 seconds because I thought sharing a large portion of it might be... iffy. I understand that this is probably frowned upon. If it is asked, I will delete the snippet from the site. It will be deleted automatically in a few months anyway due to their content storage policy, but I saved the deletion link just in case.
You have to understand - it's incredibly difficult to describe a track in text form when all you know is how it sounds.
http://vocaroo.com/i/s1pzUVdtjwjy
This is the track in question (or rather a 9-10 second snippet near the beginning). Can someone please tell me what this is called and why it isn't in the official soundtrack?

MISSING FROM THE OST:
Also, while I'm at it, can I request that the full experimental soundtrack be restored to the full soundtrack? I mean, I paid extra for this and I didn't get all the songs that I know exist. I mean heck, judging by the above track, there's even music in the game that isn't on the official OST. I even uninstalled and reinstalled my Steam OST to check. No new tracks.


Here's the names of the known tracks I know are missing from the OST currently:
-Forest Exploration 1 and 2
-Forest Battle 1 and 2 (and the alternate version of Forest Battle 2)
-Ocean Exploration 1
-Tentacle Exploration 2
and whatever else might have been left out (for example, the theoretical Desert Battle 1)
It's always a shame to look at these great tracks left out for... some reason. I guess they were considered not up to scratch or something? Honestly I like them all.

BIOME SPECIFIC MUSIC:
ALSO also, at some point could we perhaps get per-biome music, or at least better groupings per "feel"? I don't have to tell you how out of place Desert Exploration 1 sounds on a Mutated planet. So many planets share music, and so many planets can play such a wide variety of different-sounding music that it kind of makes everything blend together.

I hate to play the Terraria card, but it's a great example of what I mean. Every biome, dungeon, and partially, boss, all have unique themes associated with them. In Starbound, on the other hand, you can get the same music on any type of planet as far as I can tell, and just about any of the musics on a single planet. Some story missions even share music with plain old exploration. The music is fantastic, but the way it's implemented is lackluster.

AAAAND CUT:
That's another thing. At night, the music changes... And it does so VERY suddenly. There's no fade out or in at all. It just seems to jump to the next track rather jarringly. What's with that?