Right, I noticed a little while back that the Monsters section on the BBC Doctor Who site had included two extra monsters we hadn't seen for a little while:

Drahvins and Sea Devils.

I just wondered why they had been added. I know the Drahvins were mentioned in The Pandorica Opens, but then so were Chelonians, and the Slitheen, also the Atraxi... And the Seas Devils were briefly seen in the 'Defender of the Earth' speech in Eleventh Hour.

Now, I thought it was odd and incongruous to have those there, but not the others. I have no thoughts on why the Sea Devils were included, but I do have some thoughts about the Drahvins:

Would you like to see their returns?

excluding The Eleventh Hour, sea devils last appeared in the 5th Doctor story Warriors of the Deep, so I don't know why they're included, maybe its just because of their fleeting appearance in TEH, seems a bit pointless to include them just because of that though...

The Slitheen we already know about, and the Atraxi we know virtually nothing about. The Chelonians didn't appear in the original series, so there's not really any material that they can use without copyright trickiness. I suspect there may not be anything more complex than that.

It should be noted that Sontarans are already established as a clone race in the new series too.

Perhaps only because of their relationship to Silurians?

Yes, but their clones had independent thought, didn't they?

It's just that they had the Weeping Angels up in the monsters section before the fifth series started - I wondered if there was anything to it!