It is likely the name Long Gui comes from Chinese. Using the Pinyin transcription, among few other possible meanings, Lóng corresponds to "dragon" (龙) and Guī to "turtle" (龟) (tortoise) thus giving a "Dragon turtle" (龙龟).
Usage
See Special:Whatlinkshere/Etymology:Long Gui for a list of articles using this term.
This is an etymology page: a page detailing the origins of terminology used in the series in regards to real world culture and history.