If you’re keeping tabs on who among the ancients recognized that the Greek etymologies in the Story of Susanna (one of the Greek additions to Daniel) precluded its original composition in Hebrew, I have compiled a list of those I have found.
- Origen seems to have been the first. He writes in his Letter to Africanus (§6, or §10 in the most recent critical edition by Nicholas de Lange in SC 302) that he previously recognized the difficulty. His acknowledgment of this point is found in book 10 of his Stromata, preserved by Jerome in his Commentary on Daniel 13:54-59 (available here in Gleason Archer’s translation).
- Africanus raises the point about the etymologies in his Letter to Origen (§1, or §5 in the edition by de Lange) as one of seven arguments against the authenticity of Susanna.
- Porphyry, the neo-Platonic philosopher and anti-Christian writer, recognized the Greek etymologies and used it apparently as an argument that the entire Book of Daniel had been originally composed in Greek. This is how Porphyry’s position is related by Jerome in the preface to his Commentary on Daniel. (Again, Gleason Archer’s translation is available here. Note P.M. Casey's caution [p. 19] about deciphering Porphyry’s precise position from Jerome.) Robert M. Grant showed long ago that it is unlikely that Porphyry was dependent on Africanus or Origen, specifically because Porphyry thought the whole Book of Daniel was composed in Greek, whereas it would have been difficult for him to gain this impression from these earlier Christian writers. See Grant’s “Historical Criticism in the Ancient Church,” Journal of Religion 25 (1945): 183–96 (194). This is in contrast to other scholars who think that Porphyry was dependent on Africanus (e.g. de Lange, on p. 490 of his edition of the letters = SC 302).
- A Jewish teacher is said by Jerome to have brought this objection against the story. This is related in Jerome’s preface to his translation of Daniel (available here in Fremantle’s old translation, or here in Kevin Edgecomb’s recent translation).
Those are all the testimonia I have found. Of course, after Jerome wrote about the etymologies in his preface to the Vulgate (as it was later known) version of Daniel, it would have become common knowledge (to those who could and would read), as these prefaces were transmitted in almost all manuscripts of the Vulgate. If you know of other references to these etymologies before Jerome, please leave a comment.
By the way, modern critics are less sure than their ancient counterparts that the Greek etymologies prove that Susanna was originally written in Greek, and in this way follow Origen, who also had doubts (see his Letter §6 [10 in de Lange] and §12 [18 in de Lange]). A good discussion with an inconclusive result may be found in the new Schürer, 3/2 p. 724.