''Largirostrornis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

enantiornithean The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and cla ...

bird. One species has been named, ''Largirostornis sexdentoris''. It lived during the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

and is known from

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s found in the

Jiufotang Formation The Jiufotang Formation (Chinese: 九佛堂组, pinyin: ''jiǔfótáng zǔ'') is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms (see ...

Liaoning Liaoning () is a coastal province in Northeast China that is the smallest, southernmost, and most populous province in the region. With its capital at Shenyang, it is located on the northern shore of the Yellow Sea, and is the northernmost ...

province,

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. Some researchers believe this species to be a

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

of the similar '' Cathayornis yandica''.Zhou Z. and Wang Y. (2010). "Vertebrate diversity of the Jehol Biota as compared with other lagerstätten." ''Science China: Earth Sciences'', 53(12): 1894–1907.

''Largirostrornis'' is known from one

, slab and counterslab, found in the

province,

. The

is dated to the

period, late

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

age, 120.3 +/-0.7 million years ago.He, H.Y., Wang, X.L., Zhou, Z.H., Wang, F., Boven, A., Shi, G.H., Zhu R.X. (2004). "Timing of the Jiufotang Formation (Jehol Group) in Liaoning, northeastern China, and its implications". ''Geophysical Research Letters'' 31(13): 1709. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

fossil is in the collection of the

Institute of Vertebrate Paleontology and Paleoanthropology The Institute of Vertebrate Paleontology and Paleoanthropology (IVPP; ) of China is a research institution and collections repository for fossils, including many dinosaur and pterosaur specimens (many from the Yixian Formation). As its name suggest ...

in Beijing, China. It has been given catalog number IVPP 10531.Hou, Lianhai (1997) "Mesozoic Birds of China" Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China. Published by the Phoenix Valley Provincial Aviary of Taiwan. In Chinese, translated by Will Downs, Bilby Research Center, Northern Arizona University, January, 2001. ''L. sexdentornis'' had in 1997 a torso longer than all other known

Enantiornithes The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and cla ...

. It is slightly larger than '' Cuspirostrisornis'', with a skull about 32 millimeters long. The paired

dentaries In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

and

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

e each hold six teeth. There are tall

neural spine The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...

s on the

cervical In anatomy, cervical is an adjective that has two meanings: # of or pertaining to any neck. # of or pertaining to the female cervix: i.e., the ''neck'' of the uterus. *Commonly used medical phrases involving the neck are **cervical collar **cerv ...

and

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

vertebrae.

Etymology

The species was named and described by

Hou Lianhai Hou or HOU may refer to: * -hou, a place-name element * Hou (surname) * Hou (currency) (Chinese: ), a unit of currency in Greater China * Hou (Odder Municipality), a town in Denmark * Hou (title) (Chinese: ), a title in ancient China * Denglong (m ...

in 1997. The genus name comes from the Latin words ''largus'', "large" and ''rostrum'', "beak", and the specific name means "six-toothed" from Latin ''sex'' and ''dens''.

References

Bird genera Early Cretaceous birds of Asia Euenantiornitheans Fossils of China Fossil taxa described in 1997 {{paleo-bird-stub