What explains the distribution of new impact craters on Mars? 24 minutes into this van Karman lecture by Dr. Tamppari, the slide below is shown with symbols for transient events on Mars. Red dots represent meteoroid impacts which have occurred while MRO has been in Mars' orbit.

New impacts are almost only found at lower latitudes. And longitudinally there are two equally sized gaps at the equator. Is this because of some observational bias or is there a natural explanation?
I was on the targeting team for one of the cameras that discovered most of these new impact craters. The reason for the distribution is simply because it's easiest to find "new" impact craters in the dusty regions of Mars. Often what we see is the dark-toned blast zone created by the impact in lower-resolution data, which has a large areal footprint. Then, we target those dark-toned splotches with the higher resolution cameras---which have MUCH smaller footprints---to confirm whether or not the splotches are craters. See the attached image as an example. The dark splotches really stand out in dusty regions, but in the non-dusty areas there's nothing obvious to pick out to say "hey, there's a new crater" as a human without tediously comparing images.