My learned Armenian correspondant Seda Stamboltsyan has been looking in the electronic catalogue of the Matenadaran at Yerevan for us. She reports at least one Armenian catena in the catalogue, which includes material by Eusebius.
Doing so was not entirely straightforward, as the search tool is somewhat cranky. You have to get the exact word correct — searching for “euseb” will not bring up “eusebius”. Since the endings will vary, depending on case, this is a little bit of a pain. But typing “eusebi” (genitive case) gave 53 results; “eusebios” produced 14. Among them was this entry:
667662
Խմբագիր մեկնութիւն է. վկայութիւններ են բերուած հետեւեալ հեղինակներից՝ Կիւեղ Աղեկսանդրացի, Պիմեն, Սեւեռիտոս, Ներսէս, Յովհան Ոսկէբերան, Բարսեղ Կեսարացի, Իսիքիոս Երուսաղէմացի, Դիոնեսիոս Աղէկսանդրացի, Որոգինես, Թէոդորիտոն, Ապողինար Լաոդիկեցի, Եւսեբիոս Կեսարացի, Դիդիմոս, Ամոն, Տիմոթէոս, Աթանաս, Եփրեմ Ասորի։
Translated:
“[Manuscript number] 667662
This is a collective commentary [i.e. catena]. Testimonies are brought from the following authors: Cyril of Alexandria, Pimen, Severitos, Nerses, John Chrysostom, Basil of Caesarea, Hesychios of Jerusalem, Dionysius of Alexandria, Origen, Theodoriton, Apolinarius of Laodicea, Eusebius of Caesarea, Didimus, Amon, Timothy, Athanasius, Ephrem the Syrian.”
Clicking through gave more info. Folios 1-235 are commentaries on the Catholic epistles, and the authors above are for this. Plainly this is a catena. There was also a bit of bibliography: “cf. Vienna N 48 (Tashian, Bibliography, 234-243). Also: PO, t43, N193.” The shelfmark is Mashtots Matenadaran ms. N 1407. Date: 1596. The place where it was written is not mentioned. Scribe: Priest Pawłos (Paul).
Seda reminds us that not all the manuscripts in the Matenadaran have been catalogued to this level of detail yet. Four volumes were published, and the electronic catalogue is based on these. The fifth volume has just been published, but not yet incorporated into the online catalogue. However there are about 17,000 mss. in the Matenadaran. Each volume is around 500 mss, so there is a considerable distance still to go.
There is a brief catalogue of all the mss, but it doesn’t go to this level of detail.
PO 43 does indeed contain a publication of an Armenian catena on the Catholic epistles:
Volume 43. La chaîne arménienne sur les Épîtres catholiques. I, La chaîne sur l’Épître de Jacques / Charles Renoux…
So there is a publication with French translation in PO 43/1 (N193), Turnhout 1985; 44/2 (N198), 1987; 44/1-2 (205-206), 1994; 47/2 (N210), 1996. I queried the manuscript numeral, as that didn’t look like a shelfmark to me. (It’s probably the electronic catalogue’s database primary key!)
Seda Stamboltsyan tells me that she has been doing translations from Classical Armenian into modern Armenian, also editing and proofreading texts in Armenian, preparing critical editions of Classical Armenian texts. I think those of us that are illiterate, at least in Armenian, can be very grateful to her for her efforts!