About that mural...

So the mural we saw via Bungie showed some interesting things but there's one thing I'm not seeing anyone talking about. The Guardian we see here and here only has 8 fingers and 8 toes... Not only that but the non skeletal side isn't dressed in anyway that guardians usually do (apart from the Huanted ornament set). Obviously it could be highly stylised or even metaphorical given the half skeleton appearance but that doesn't explain the limbs. Do they think guardians are alien? Or did they find a guardian that wasn't human?