The intro to the Bestiary says:
Space/Reach: The creature's space and reach—if the creature's space and reach are standard (one 5-foot square and a reach of 5 feet), this line is omitted.
But then Big and Little Creatures in Combat says:
A Tiny creature typically occupies a space only 2-1/2 feet across, so four can fit into a single square. 25 Diminutive creatures or 100 Fine creatures can fit into a single square. Creatures that take up less than 1 square of space typically have a natural reach of 0 feet, meaning they can’t reach into adjacent squares. They must enter an opponent’s square to attack in melee.
It seems most reasonable to me that cat-sized creatures have 0' reach unless they have rules text to state otherwise (and the second quote seems to agree)...but I'll admit the first quote seems to say otherwise. Is there an official ruling as to what the reach is for Tiny (or smaller) creatures without a listed reach?