Three specimens of a new iguanodontian were discovered in the Khuren Dukh Formation of Mongolia by an expedition led by Mongolian paleontologist Rinchen Barsbold.

These three specimens, stored in the Mongolian Natural History Museum, were found within the same sediments that had yielded the iguanodontian Altirhinus, but comparisons showed that they represented different taxa and so in 2018 American paleontologist Terry Gates and colleagues named them Choyrodon barsboldi.

The quarry the holotype was found in is a thick brown-black siltstone at the Khuren Dukh locality of the formation, with an age of approximately middle to late Albian based on palynology.

They found that the presence or absence of an antorbital fenestra in adults did not significantly change the relationships of Choyrodon, with it either as the sister taxon of Eolambia or an intermediate early hadrosauroid.

[1] Altirhinus Bolong Choyrodon Equijubus Jinzhousaurus Batyrosaurus Probactrosaurus Eolambia Protohadros Bactrosaurus Levnesovia Shuangmiaosaurus Tethyshadros Telmatosaurus Hadrosauridae