''Parvavis'' is a genus of

enantiornithine 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 Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

, known from the upper Cretaceous of China in the Jiangdihe Formation. The type and only species, ''Parvavis chuxiongensis'', was recovered in Luojumei Village, Chuxiong City, Yunnan Province, southern China, and it was the only known Mesozoic bird from south China at the time of its discovery. Based on its bone structure, the holotype was determined to be nearly fully grown at its time of death and would have been smaller than ''

Iberomesornis ''Iberomesornis'' ("Spanish intermediate bird") is a monotypic genus of enantiornithine bird of the Cretaceous of Spain. Discovery In 1985 the fossil of ''Iberomesornis'' was discovered by Armando Díaz Romeral in the Early Cretaceous Caliza ...

'', the smallest known enantiornithine prior to the description of ''Parvavis''.

History of Discovery

In 2010, the skeleton of a small bird was found near Luojumei, a village close to the city of Chuxiong in the

Yunnan province Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the C ...

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 ...

, and in 2014 the type species ''Parvavis chuxiongensis'' was named and described by Wang Min,

Zhou Zhonghe Zhou Zhonghe (; born 19 January 1965 in Jiangdu, Jiangsu province) is a Chinese palaeontologist. He described the ancient bird ''Confuciusornis''.. Zhou graduated from Nanjing University and earned a Ph.D. in Biology in 1999 from the University o ...

and Xu Guanghui. The

genus name Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

is derived from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

prefix “parv”, which means small, and “avis” which means bird. The

species name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

refers to the location where the fossil was found, near the city of Chuxiong. Parvavis is the first bird known from the Upper-Cretaceous of China and the first

mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

bird from Southern China. The fossil,

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 ...

IVPP V18586/1, was found in lake deposits of the Jiangdihe formation. It consists of a partially complete and articulated skeleton with parts of the skull and impressions of feathers on some of the rock. Of the spine, only the tail and pygostyle were preserved, and of the skull only the back. Furthermore,

histological Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...

research suggests the animal was close to adult size when it died, but that it was unusually small in size for an

Enantiornithine 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 ...

. This highlights the highly variable body sizes in this group of animals.

Description

''Parvavis'' is, like the genus name suggests, a small bird with a

wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the other wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingspan of ...

of about 15 centimeters. Other than the wingspan, the descriptors of the animal managed to identify a couple of differentiating characteristics, like the fact that the bottom joint of the second

metatarsal The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the med ...

is wider than those of the other metatarsals. The other two characteristics they identified are that the bottoms of the second and fourth metatarsals don't reach the hinge surfaces of the third metatarsal, and the fact that the

claw A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tarsus ...

on the fourth toe is reduced. The latter two characteristics aren't unique on their own, but they are unique in combination with the first one.

Classification

Cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analyses put Parvavis in a relatively basal position within the Enantiornithes, outside

Longipterygidae Longipterygidae is a family of early enantiornithean avialans from the Early Cretaceous epoch of China. All known specimens come from the Jiufotang Formation and Yixian Formation, dating to the early Aptian age, 125-120 million years ago. Descri ...

. This indicates that these basal forms existed for much longer than previously suspected.

References

{{Taxonbar, from=Q15880538 Enantiornitheans Extinct birds of Asia Fossil taxa described in 2014