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| Yuornis | |
|---|---|
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| Skull diagram | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Avialae |
| Clade: | †Enantiornithes |
| Genus: | †Yuornis Xuet al., 2021 |
| Species: | †Y. junchangi |
| Binomial name | |
| †Yuornis junchangi Xuet al., 2021 | |
Yuornis (meaning "Henan bird", after the one Chinese character abbreviation of Henan,豫 (pinyin:Yù)) is anextinctgenus ofenantiornithinebird known from theLate Cretaceous ofHenan,China. It contains one species,Yuornis junchangi, named after the lateLü Junchang.[1]
The holotype specimen is remarkably complete for a Late Cretaceous enantiornithine, possessing a three dimensionally-preserved skull and partial skeleton. Unlike most enantiornithines, the skull ofYuornis was completely toothless and convergently similar to that ofneornithines (modern birds). Thelacrimal andpostorbital bones are completely absent and thesquamosal is strongly reduced; these losses leave theantorbital fenestra andsupratemporal fenestra confluent with theorbit (eye socket), also like some modern birds. Unlike modern birds, thepremaxilla makes up a smaller portion of the lower edge of the snout, while thequadratojugal is unusually large and complex.[1]
Thephylogenetic analysis of Xuet al. (2021) positionedYuornis as thesister taxon toGobipteryx, another toothless Late Cretaceous enantiornithean. This would by definition place Yuornis in the familyGobipterygidae. However, the traits supporting this relationship were all related to tooth loss, a condition which is known to haveconvergently evolved many times in Mesozoic bird lineages. As a result, the authors refrained from formally consideringYuornis a gobipterygid.[1]
