I suppose another possibility might be catalpa , which seems to be similar to paulownia in pore structure and in the tendency for heartwood formation to start in second year growth . It is also light , but should normally be heavier than paulownia .
The largest piece of paulownia I have is 176 cc in volume and weighs 66 gm at about 6% moisture . It was from a tree in IL with some growth rings of 1 cm or more . Your wood was from a tree growing under more adverse conditions , with only one row of early wood pores instead of 5 or 6 , so it should be denser than my sample .
My vote would be paulownia . I would cut 2-4 inch chunks of the curled portion at an angle and make them into pen stands , holding a pen made from the same wood . Should be good for $100 a set , even with a slimline .