Mengciusornis dentatus was named by Wang et al. (2020) [Medium-sized basal ornithuromorph birds differing from other ornithuromorphs in the unique combination of the following characters: ‘V’-shaped robust furcula with a hypocleidium; humerus with large rectangular deltopectoral crest; distodorsal corner of deltopectoral crest pointed; proximal phalanx of major digit with parallel cranial and caudal margins; metatarsals III coplanar with metatarsals II and IV; and metatarsals II through IV only partially fused distally.]. Its type specimen is IVPP V26275, a skeleton (a nearly complete and partially articulated skeleton preserved on a single slab with traces of feathers), and it is a 3D body fossil. Its type locality is Lamadong, Jianchang, which is in an Aptian lacustrine sandstone/mudstone in the Jiufotang Formation of China.