I just added the image and caption below to the Trombone History Timeline (16th century). I will also be adding it to the collections Angel Trombonists Throughout History and How to Hold a Sackbut. And yes, that tubing does appear to just stop abruptly!

c. 1590—Rome, Italy: A fresco by Cristoforo Roncalli (Pomarancio) in the cupola of Sant’Andrea della Valle depicts music-making angels, including one playing trombone (see detail and full image below; public domain).