It definitely is an interesting addition to the article The only question is whether you can really justify fair use in this case On the other hand I m not sure if you can really assert copyright over plain text PNAS s copyright policy on submissions suggests that unlike many other journals PNAS doesn t demand that you sign over copyright The question then is whether the copyright belongs to FTE or to Nick Matzke I would suggest sending Nick and email and seeing if he will release the figure under a suitable copyleft license I clearly see it as a valuable addition to the article one that helps the reader s appreciation of the topic