Liaoxiornis
Encyclopedia
Liaoxiornis is a dubious
genus
of enantiornithine bird. The only named species is Liaoxiornis delicatus, described by Hou and Chen in 1999. Because the species was named for a hatchling specimen, it cannot be matched with adult specimens, and so it is impossible to determine which, if any, birds from the same rocks represent adults of this species. Luis Chiappe and colleagues therefore regarded it as a nomen vanum ("empty name") or at least a nomen dubium, and recommended that use of the name be abandoned.
), was named by Li and Li as Lingyuanornis parvus. Soon afterwards, it was found that both museums had obtained different slabs of exactly the same specimen; because Liaoxiornis delicatus was named slightly earlier, that name takes precedence.
The type specimen is complete and articulated, and while it has mature flight feathers, features such as bones tipped in cartilage, small breastbone, large head and eye and unfused skeleton indicate that it was a juvenile. Zhou and Hou (2001) assigned it to the group Enantiornithes
, and described it as being equally as advanced as Cathayornis
. Several other specimens of juvenile enantiornithines have been found in the same strata, but because all of them are juveniles, it is impossible to discern whether or not they represent the same species, and later authors have suggested that the taxon should be ignored as invalid for this reason.
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of enantiornithine bird. The only named species is Liaoxiornis delicatus, described by Hou and Chen in 1999. Because the species was named for a hatchling specimen, it cannot be matched with adult specimens, and so it is impossible to determine which, if any, birds from the same rocks represent adults of this species. Luis Chiappe and colleagues therefore regarded it as a nomen vanum ("empty name") or at least a nomen dubium, and recommended that use of the name be abandoned.
History
In 1999, Hou and Chen of the Nanjing Institute of Paleontology and Geology briefly described a specimen of very small bird obtained by the museum and named it Liaoxiornis delicatus. One month later, another specimen, obtained by the National Geological Museum of China (BeijingBeijing
Beijing , also known as Peking , is the capital of the People's Republic of China and one of the most populous cities in the world, with a population of 19,612,368 as of 2010. The city is the country's political, cultural, and educational center, and home to the headquarters for most of China's...
), was named by Li and Li as Lingyuanornis parvus. Soon afterwards, it was found that both museums had obtained different slabs of exactly the same specimen; because Liaoxiornis delicatus was named slightly earlier, that name takes precedence.
The type specimen is complete and articulated, and while it has mature flight feathers, features such as bones tipped in cartilage, small breastbone, large head and eye and unfused skeleton indicate that it was a juvenile. Zhou and Hou (2001) assigned it to the group Enantiornithes
Enantiornithes
Enantiornithes is an extinct group of primitive birds. They were the most abundant and diverse avialans of the Mesozoic. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over 50 species of Enantiornithines have been named, but some...
, and described it as being equally as advanced as Cathayornis
Cathayornis
Cathayornis is a genus of enantiornithine bird from the Jiufotang Formation of Liaoning, People's Republic of China and, in the case of the possible species C...
. Several other specimens of juvenile enantiornithines have been found in the same strata, but because all of them are juveniles, it is impossible to discern whether or not they represent the same species, and later authors have suggested that the taxon should be ignored as invalid for this reason.