Sydney ant identification help?

[Numbat]

Hi, is anyone able to tell from these grainy photos if this is likely to be a queen ant?
https://imgur.com/a/USSnPAO
I'm completely new to ant collecting and I have a very old phone with poor quality camera and not a very good magnifying glass.
It is spring in Sydney and we had a rain storm last night. I found 2 of these ants, which looked bigger than the other black ants nearby. The other ants were scurrying around moving dirt and what looked like eggs. But these were just wandering off. I can't see if they have wing scars or not but after capture, I observed one tending to it's bottom a lot.
Sorry about the poor quality photos but any information would be helpful.
Thanks.

[LasiusSapien]

ok that looks like green head ant so i'm thinking its a member of the Rhytidoponera sp. which makes id-ing queens quite hard as they look the same as the workers just with slightly bigger bum, there's some side by side pic's in this wiki page

https://en.wikipedia.org/wiki/Green-head_ant

[Numbat]

Thanks! I'll look them up.
I'm not sure if it's that green but I'll try to get a better magnifying glass to check.

[Numbat]

I just found another one today from the same area, which is bigger than the 2 yesterday, so now I'm not entirely sure the first 2 are queens. Will wait and see! The new one does have a slightly metallic sheen.

I also found one with wings in my backyard, but I let it fly off.

[Numbat]

I found another 2 today of these ants. It was a bright sunny day so I saw they definitely have a green metallic sheen, especially the head.

Slightly better pics of one:
https://imgur.com/a/1Zti1UX

Can anyone tell me if this is likely to be a queen?

And if so, I read they are semi-claustral. Hints on what to feed them?