|Named By:||Min Zhu, Xiaobo Yu, Per Erik Ahlberg, Brian Choo, Jing Lu, Tuo Qiao, Qingming Qu, Wenjin Zhao, Liantao Jia, Henning Blom & You'an Zhu in 2013|
|Time Period:||Late Ludlow|
|Location:||China, Yunnan Province|
|Size:||Roughly estimated at about 20 centimetres long|
|Classification:||| Chordata | Gnathostomata | Placodermi ||
Entelognathus primordialis ("primordial complete jaw") is a placoderm from the late Ludlow epoch of Qujing, Yunnan, 419 million years ago.
A team led by Min Zhu of the Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology in Beijing discovered the intact, articulated fossil in rock formations at Xiaoxiang reservoir.