| 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 |
| Diet: | Carnivore |
| Fossil(s): | Partial remains |
| 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.