Gretcheniao sinensis was named by Chiappe et al. (2019) [A medium-sized enantiornithine bird sharing the following traits with other “bohaiornithids”: robust rostrum with large subconical teeth that are gently recurved, caudolaterally directed lateral trabeculae of the sternum, and strongly curved and elongated pedal claws. The new species is distinguishable from other Bohaiornis-like enantiornithines in having a unique combination of characters including: humeral bicipital area scared by a large cranioventrally facing fossa; slightly tapered omal ends of the furcular rami; ventral tubercle at the convergence of the furcular rami; slender coracoid with a sternal margin that is slightly more than 1/3 the length of the bone and a straight lateral margin; significantly elongated carpometacarpus; and metacarpal II carrying a protuberance on its dorsal surface.]. Its type specimen is BMNH Ph 829, a skeleton (nearly complete skeleton, largely exposed in ventral view, and contained in a single slab), and it is a 3D body fossil. Its type locality is Huludao City (Jianshangou Unit of the Yixian Formation), which is in a Barremian/Aptian lacustrine shale/mudstone in the Yixian Formation of China.