Question

read this text.
southern africas so - called fairy circles—round patches of soil surrounded by grass—were once thought to be caused by termites.
is this an appropriate use of an ellipsis?
\southern africas so - called fairy circles... were once thought to be caused by termites.\
yes
no, because the text with an ellipsis is no longer grammatically correct

Explanation:

An ellipsis is used to indicate an omission. In the original text, "round patches of soil surrounded by grass" is omitted. The sentence with the ellipsis is still grammatically correct.

Answer:

yes