Looks ok for A. porosus. A. boisduvalii can look similar in the area with relatively poorly developed black markings on the elytra. This seems to have the fringes of white setae at the side margin of the pygidium characteristic of A. porosus.
These seem to be two different species, but neither of them is A. concolor. First one may be A. porosus (but would need a view of the rear to confirm), second one A. montanus.
