''Gobipteryx'' (from Gobi eferring to the Gobi Desert where it was first discovered and Greek pteryx "wing") is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of prehistoric bird from the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

Age Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

Period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

.Elżanowski, A. (1974)
"Preliminary note on the Palaeognthous bird from the Upper Cretaceous of Mongolia"
''Palaeontologia Polonica'' 30:103-109, plates 32-33. It is not known to have any direct descendants. Like the rest of the

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

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

, ''Gobipteryx'' is thought to have gone extinct near the end of the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

.Padian, K. (2004). "Basal Avialae". chptr 11, in Weishampel, D.B., Dodson, P. and Osmólska, H. (eds.): ''The Dinosauria'' 2nd Edition. University of California Press, Berkeley .

Description

Based on a

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

length of 45 millimeters, ''Gobipteryx'' has been estimated to be approximately the size of a

partridge A partridge is a medium-sized Galliformes, galliform bird in any of several genera, with a wide Indigenous (ecology), native distribution throughout parts of Europe, Asia and Africa. Several species have been introduced to the Americas. They ar ...

.Elżanowski, A. (1976): Palaeognathous bird from the Cretaceous of Central Asia ''

Nature Nature is an inherent character or constitution, particularly of the Ecosphere (planetary), ecosphere or the universe as a whole. In this general sense nature refers to the Scientific law, laws, elements and phenomenon, phenomena of the physic ...

'' 264: 51-53. Its bones are fibrolamellar.Chinsamy, A., Elżanowski, A. (2001): Bone histology: Evolution of growth pattern in birds ''Nature'' 412: 402-403. The skull's general shape is gradually tapering toward the front. ''Gobipteryx'' has a toothless

beak The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for pecking, grasping, and holding (in probing for food, eating, manipulating and ...

formed from the fusion of the

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 mammals h ...

e bones.Chatterjee, S. (1997): ''The Rise of Birds: 225 Million Years of Evolution'' The Johns Hopkins University Press . The skull is characterized as being rhynchokinetic with the

pterygoid bone The pterygoid is a paired bone forming part of the palate of many vertebrates, behind the palatine bone In anatomy, the palatine bones (; derived from the Latin ''palatum'') are two irregular bones of the facial skeleton in many animal specie ...

s articulating with both the

vomer The vomer (; ) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. The vomer forms ...

sElżanowski, A. (1977)
"Skulls of ''Gobipteryx'' (Aves) from the Upper Cretaceous of Mongolia"
''Palaeontologia Polonica'' 37: 153-166. and the palatine. The nares are tear shaped and the

choana The choanae (: choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the pharynx, in humans and other mammals (as well as crocodilians and most skinks). They ...

is located below them, more rosteral than in most modern birds.Chiappe, Luis M.; Norell, Mark and Clark, James (2001)
"A New Skull of ''Gobipteryx minuta'' (Aves: Enantiornithes) from the Cretaceous of the Gobi Desert"
''American Museum Novitates'' 3346: 1–15. The nares are smaller than the

antorbital fenestra An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with Archosauriformes, archosauriforms, first appearing during the Triassic Period. Among Extant ...

e, a basal feature for

ornithurae Ornithurae (meaning "bird tails" in Greek) is a natural group that includes modern birds and their very close relatives such as the ichthyornithines and the hesperornithines. This clade is defined in the ''PhyloCode'' by Juan Benito and collea ...

birds. In addition, ''Gobipteryx's'' skull has an articulated rostrum. The

jaw The jaws are a pair of opposable articulated structures at the entrance of the mouth, typically used for grasping and manipulating food. The term ''jaws'' is also broadly applied to the whole of the structures constituting the vault of the mouth ...

hinge is associated with the articulation of the quadrate with the pterygoid processes. The articular region of the mandible contains internal and retroarticular processes and has uniform

symphysis A symphysis (, : symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing together o ...

. This animal has a large, uniform, and sutureless

braincase In human anatomy, the neurocranium, also known as the braincase, brainpan, brain-pan, or brainbox, is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calv ...

. The

vertebral column The spinal column, also known as the vertebral column, spine or backbone, is the core part of the axial skeleton in vertebrates. The vertebral column is the defining and eponymous characteristic of the vertebrate. The spinal column is a segmente ...

consists of at least 19 presacral vertebrae, the last six of these being dorsals.Elżanowski, A. (1981)
"Embryonic Bird Skeletons from the Late Cretaceous of Mongolia"
Palaeontologica Polonica 42: 147-179. The

neural spines Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

of the twelfth and thirteenth vertebrae form the nuchal blade, which represents the point of greatest elevation in the vertebral column. The

scapula The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side ...

contains a prominent

glenoid labrum The glenoid labrum (glenoid ligament) is a fibrocartilaginous (but not fibrocartilage, as previously thought) structure attached around the rim of the glenoid cavity on the shoulder blade. The shoulder joint is considered a ball-and-socket joint ...

and tapers backward, ending as thin rods. The coracoids are slightly concave anteriorly and are separate from the scapulae dorsally. They also stick out from the neck on either side. ''Gobipteryx's''

clavicle The clavicle, collarbone, or keybone is a slender, S-shaped long bone approximately long that serves as a strut between the scapula, shoulder blade and the sternum (breastbone). There are two clavicles, one on each side of the body. The clavic ...

s curve in a way that is consistent with that of other birds. The

humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

is posteriorly convex (a normal trait for birds) and the head is comma-shaped. ''Gobipteryx's''

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

is about twice as thick as the

radius In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

Metacarpal In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular bones that form the intermediate part of the hand between the phalanges (fingers) and the carpal bones ( wrist bones), which articulate ...

s II and III have been found in embryonic fossils and are observed to be about equal size and are in close contact with each other.

Paleobiology

Flight

''Gobipteryx'' is believed to have been capable of flight. The scapula is long, and therefore, well suited for flight by having more area for muscle attachment. In addition, the

forelimb A forelimb or front limb is one of the paired articulated appendages ( limbs) attached on the cranial (anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used inst ...

of ''Gobipteryx'' is more than twice the length of the

thorax The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...

, falling within the acceptable range observed in flying birds.

Development

''Gobipteryx'', along with other enantiornithes, is thought to have superprecocial development, in which it was capable of flying upon hatching. Evidence for this comes from the fact that the forelimbs and shoulders of advanced embryos are almost completely

ossified Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

. In addition, the growth of ''G. minuta'' has been shown to slow down immediately following hatching. This suggests that it was highly mobile in its life, since locomotion has been shown to slow the growth of young birds by focusing energy and resources elsewhere. This onset of flight so early in life is not seen in most modern birds, which begin flying when they have reached or are close to full size.

History

The first specimens were two damaged skulls discovered as part of the 1971 Polish-Mongolian Paleontological Expedition to the

Gobi Desert The Gobi Desert (, , ; ) is a large, cold desert and grassland region in North China and southern Mongolia. It is the sixth-largest desert in the world. The name of the desert comes from the Mongolian word ''gobi'', used to refer to all of th ...

by Dr. Teresa Maryańska, however, at the time, it was not immediately recognized that both of these skulls belonged to ''Gobipteryx''. It was first found in the

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

s of the Lower Nemegt Beds of the

Barun Goyot Formation The Baruungoyot Formation (also known as Barun Goyot) is a geological formation dating to the Late Cretaceous Period. It is located within and is widely represented in the Gobi Desert Basin, in the Ömnögovi Province of Mongolia. Descriptio ...

of the

Nemegt Basin The Nemegt Basin is a geographical area in the northwestern Gobi Desert, in Ömnögovi Province, southern Mongolia. It is known locally as the "Valley of the Dragons", since it is a Bone bed, source of many fossil finds, including dinosaurs, dino ...

. The

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 ...

specimen is housed at the Institute of Paleobiology of the

Polish Academy of Sciences The Polish Academy of Sciences (, PAN) is a Polish state-sponsored institution of higher learning. Headquartered in Warsaw, it is responsible for spearheading the development of science across the country by a society of distinguished scholars a ...

Warsaw Warsaw, officially the Capital City of Warsaw, is the capital and List of cities and towns in Poland, largest city of Poland. The metropolis stands on the Vistula, River Vistula in east-central Poland. Its population is officially estimated at ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...

and was first described by Dr. Andrzej Elżanowski using a single damaged skull. Initially, ''Gobipteryx'' was classified as a member of the clade

Palaeognathae Palaeognathae (; ) is an infraclass of birds, called paleognaths or palaeognaths, within the class Aves of the clade Archosauria. It is one of the two extant taxon, extant infraclasses of birds, the other being Neognathae, both of which form Neo ...

on the basis of its jaw and palate. However, in 1981, Dr. Cyril Walker defined the clade enantiornithesWalker, C. A. (1981): New subclass of birds from the Cretaceous of South America ''Nature'' 292 p. 51-53. and ''Gobipteryx'' was reclassified as an enantiornithes bird. In 1996,

Evgeny Kurochkin Yevgeny Nikolayevich Kurochkin (Евгений Николаевич Курочкин; 12 July 1940 - 13 December 2011) was a Russian paleornithologist at the Paleontological Institute of the Russian Academy of Sciences. He served as President of ...

described a new bird known as ''Nanantius valifanovi'' also from the Barun Goyot Formation.Kurochkin, E. (1996): A new enantiornithid of the Mongolian Late Cretaceous, and the general appraisal of the Infraclass Enantiornithes (Aves). ''Russian Academy of Sciences, Palaeontological Institute, Special Issue'': 1-50. However, it was later discovered that ''N. valifanoi'' was actually a new misidentified specimen of ''Gobipteryx minuta''. The mistake was, at least in part, due to a misidentification of the

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

and

dentary In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone ...

bones of the skull. In 1994, an expedition to the Gobi Desert was conducted by the

American Museum of Natural History The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...

and the

Mongolian Academy of Sciences The Mongolian Academy of Sciences (MAS; , ''Mongol ulsyn Shinjlekh ukhaany Akademi'') is Mongolia's first centre of modern sciences. It came into being in 1921 when the government of newly independent Mongolia issued a resolution declaring the e ...

, where a well preserved ''Gobiptetyx minuta'' skull was found in the Nemegt Basin. This new specimen provided further evidence for the placement of ''Gobipteryx'' into enantiornithes. In addition, it allowed for the reconstruction of the palate, which was poorly understood in

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 ...

birds. Also during the 1971 Polish-Mongolian Paleontological Expedition to the Gobi Desert, in which the first specimens were found, advanced

embryo An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sp ...

s of ''Gobipteryx minuta'' were found. Seven specimens in total were found, including two skeletons in the redbeds of Khermeen Tsav in Mongolia's Gobi Desert. These embryos made up the second confirmed embryonic fossils from before the

Quaternary Period The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

as well as the first confirmed postcranial fossils of ''G. minuta'' found.

References

{{Taxonbar, from=Q5575539 Enantiornithes Late Cretaceous birds of Asia Djadochta fauna Gobi Desert Fossil taxa described in 1974