Delineavit

Farjon, the conifer guy, is a Brit, and uses a lot of academic Latin in his book. His botanical drawings are all signed
    Aljos Farjon
    del. 1990
(or whatever year). 'del.'? No online search teased it out, no lists of Latin abbreviations had it, nor mentioned 'delineate' which seemed the best guess. What to do? I emailed G., veteran art teacher, who a few decades ago drew a natural history field guide for Manomet Bird Observatory. He didn't know either.

At the public library this afternoon, there was a big dictionary under my elbow, so I explored the neighborhood of delineate...

delineavit. English Latin. he drew (this) she drew (this). Abbr. del.'

Smiled all the way home, a reference librarian to my bones...