When I turn this bathroom faucet on and off, the water flow is somewhat irregular so I tried looking at the aerator to see if it needs cleaning:

What kind of aerator is this and how do I remove it?

It doesn't look like any of the aerators that I can find by searching the web. I'm not sure what manufacturer made this faucet as it has no labels on it. I tried to put a screwdriver in there and turning but was not able to make it move. Do I need a tool specifically for this aerator?

Viewed from above: