When I looked the word Afar up in Oxford American dictionary the following definition was given:
(pl. same or Afars) a member of a people living in Djibouti, Eritrea, and Ethiopia
My query: Is the last comma optional in BE?
I believe it’s a case of serial/Oxford comma when it’s up to you to decide whether to insert/omit the comma.
***** NOT A TEACHER *****
Hello, Foreigner:
I am pretty sure that most American teachers would suggest a comma after “dictionary.”
I do not wish to nitpick, but may I also point out two more tiny things?
a. I would prefer “When I looked up the word …”
b. … in the Oxford …
James
Hello James M,
As I once said, it is the very thing I have always needed!
Thank you very much for correcting me and I have no objection to your correcting me at all, vice versa I would be VERY GLAD! 
Hello, Foreigner:
You are very welcome.
Since you want corrections, may I most respectfully suggest that “vice versa” is probably not what you meant.
I think that you meant something like “On the contrary, I welcome corrections.”
James
Thanks a lot!..)))