Hm. This feels like an interesting start; anomalous evolution is something that catches my eye once in a while. Though, I'm not too sure if this sets this apart from the generic doomsday scenario that the site has?
And what is the anomaly here? The former half of your summary somewhat gave "anomalous evolution" vibes but then some bits seemed to describe it as somewhat of a biohazard? Unless you're talking about some anomalous alteration to environmental pressures to cause the start of the deviation from the Homo sapien species, I felt like I was left a little too in the dark on what the actual anomaly was here.
Hmm; the bit about the Foundation intentionally taking drastic action that are contradictory to their own motto feels reminiscent of SCP-5000 here. This really isn't bad, but I'm a little concerned on whether this would be very distinguishable from that? Replacing the entity that the Foundation's trying to destroy (which was theorized to be pain itself) with your idea of a hidden anomalous human species, I feel that the two feel… a bit too close? 5000 worked because the introduction really hooked us in with a more grounded version of something horrific happening while maintaining that sense of mystery on why the Foundation's doing this; I'm not sure if laying out the anomaly all at one go may kinda… make it a bit of a less engaging read?
Idk; I feel that this didn't… feel high stakes enough for some reason? Like, yeah, it sucks to have some other species wipe us out, but… I'm not sure if the anomaly here is enough to really hook me in and make me care about the story? I can be completely wrong about this and 5000 being a little too similar in terms of the "Foundation destroying humanity" aspect, so yeah. The story seems to end with a site lockdown from your layout, which I'm not sure if it would be punchy enough for a climax? Because it still all boils down to the end of the world stuff, which feels like pretty well-trod grown, especially in SCP context.