''Parvavis'' is a genus of

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 cl ...

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

, 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'' ("Iberian 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 an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

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

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

and Xu Guanghui. The

genus name Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial spec ...

is derived from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

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

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

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 is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

bird from Southern China. The fossil,

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

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 that studies the microscopic anatomy of biological tissue (biology), tissues. Histology is the microscopic counterpart to gross anatomy, which looks at large ...

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

. 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 opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingsp ...

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 (: metatarsi) are a group of five long bones in the midfoot, located between the tarsal bones (which form the heel and the ankle) and the phalanges ( toes). Lacking individual names, the metatarsal bones are ...

is wider than those of the other metatarsals. The other two characteristics they identified are that the bottoms of the second and fourth metatarsals do not 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 Arthro ...

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 ( ; from Ancient Greek 'branch') 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 ...

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. Descr ...

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

References

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