Inner tube - series of dot marks and a puncture, what has caused it? This is on the outside of the tube.  There is a series of small dots marks about 1-2mm apart, and one of them has turned into a puncture.  

I've felt around the inside of the wheel, and the inside of the rim.  Everything feels normal.  

I thought maybe the inner tube had turned, and the spoke had poked through, but the marks seem too close together to be caused by the spikes.

Anyone got any ideas?  I'm wondering if its safe to just put another tube in?
As the holes appear to be on the raised ribs of the tube wall, it seems something pointed was scraped over the tube.

I'm guessing the damage was done before the tube was installed. Tubes cant move around in the tire, and a tire really cannot move on the rim either.

Update: perhaps there might have been a small sharp object caught between tube and tire during tube installation, that migrated along the tube causing the scratch mark.  

In any case inspect the inside of the tire very carefully, both visually with a good bright light and tactually by running you fingers over the inner surface. Small sharp foreign objects can be hard to detect if they are just poking out of the rubber surface.