Temporal range: Early Cretaceous
|A pillow of Largirostrornis sexdentoris|
| †Largirostrornis sexdentoris|
Largirostrornis is a genus of enantiornithine bird. One species is known, Largirostornis sexdentoris. It lived during the Early Cretaceous and is known from fossils found in the Jiufotang Formation in Liaoning province, People's Republic of China. Some researchers believe this species to be a synonym of the similar Cathayornis yandica.
It is known from one fossil, slab and counterslab, found in the Jiufotang Formation in Liaoning province, People's Republic of China. The Jiufotang Formation is dated to the Early Cretaceous period, Aptian age, 120.3 +/-0.7 million years ago.
The holotype fossil is in the collection of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China. It is given catalog number IVPP 10531.
Largirostrisornis sexdentornis has a torso longer than all other known enantiornithines. It is slightly larger than Cuspirostrisornis, with a skull about 32 millimeters long. The dentary and premaxilla each hold six pairs of teeth. There are tall neural spines on the cervical and dorsal vertebrae.
The Genus name comes from the Latin words for "large" and "beak", and the species name means "six teeth".