''Gobipteryx'' (from Gobi eferring to the Gobi Desert where it was first discovered and Greek pteryx “wing”) 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 ...

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. Campanian s ...

Age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or 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 younger 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 ''creta'', the ...

Period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

.Elżanowski, A. (1974): Preliminary note on the Palaeognthous bird from the Upper Cretaceous of Mongolia ''Palaeontologia Polonica'' 30. 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 avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and cla ...

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

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

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

.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 is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

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 a ...

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

Nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...

'' 264: 51-53. Its bones are fibrolamellar.Chinsamy, A., Elżanowski, A. (2001): Bone histology: Evolution of growth pattern in birds ''Nature'' 412.

Skull

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 eating, preening, manipulating objects, killing prey, fighting, probing for food ...

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 mammal has b ...

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 () are two irregular bones of the facial skeleton in many animal species, located above the uvula in the th ...

s articulating with both the

vomer The vomer (; lat, vomer, lit=ploughshare) 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 maxill ...

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

choana The choanae (singular choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the throat in tetrapods, including humans and other mammals (as well as crocodilia ...

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

/ref> 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 archosauriforms, first appearing during the Triassic Period. Among extant archosaurs, birds ...

e, a basal feature for

ornithurae Ornithurae (meaning "bird tails" in Greek) is a natural group which includes the common ancestor of ''Ichthyornis'', ''Hesperornis'', and all modern birds as well as all other descendants of that common ancestor. Classification Ernst Haeckel coi ...

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

jaw The jaw is any opposable articulated structure 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 and serv ...

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 (, pl. 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 ...

. This animal has a large, uniform, and sutureless

braincase In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan 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 calvaria or skul ...

Vertebral Column

The

vertebral column The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordata, ...

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 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 ...

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

Shoulder Girdle

The

scapula The scapula (plural 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 eithe ...

contains a prominent

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

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, or collarbone, is a slender, S-shaped long bone approximately 6 inches (15 cm) long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on the left and one on the rig ...

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

Limbs

The

humerus The humerus (; ) 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 and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

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

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

is about twice as thick as the

radius In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...

Metacarpal In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...

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 instead. ...

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

thorax The thorax or chest is a part of the anatomy of humans, 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 divisions of the cre ...

, 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 Cell (biology), cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes ...

. 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 Locomotion means the act or ability of something to transport or move itself from place to place. Locomotion may refer to: Motion * Motion (physics) * Robot locomotion, of man-made devices By environment * Aquatic locomotion * Flight * Locomo ...

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 (Chinese: 戈壁 (沙漠), Mongolian: Говь (ᠭᠣᠪᠢ)) () is a large desert or brushland region in East Asia, and is the sixth largest desert in the world. Geography The Gobi measures from southwest to northeast an ...

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 sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

s of the Lower Nemegt Beds of the

Barun Goyot Formation The Barun Goyot Formation (also known as Baruungoyot Formation or West Goyot Formation) 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 Pro ...

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 source of many fossil finds, including dinosaurs, dinosaur eggs, ...

. 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 ...

specimen is housed at the Institute of Paleobiology of the

Polish Academy of Sciences The Polish Academy of Sciences ( pl, Polska Akademia Nauk, 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 ...

Warsaw Warsaw ( pl, Warszawa, ), officially the Capital City of Warsaw,, abbreviation: ''m.st. Warszawa'' is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland, and its population is officia ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...

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 a infraclass of birds, called paleognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contai ...

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 t ...

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 The maxilla (plural: ''maxillae'' ) in vertebrates 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 t ...

and

dentary 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 tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...

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 (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...

and the

Mongolian Academy of Sciences The Mongolian Academy of Sciences (, ''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 establi ...

, 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 ( ), 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 ...

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 an initial stage of development of 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 spe ...

s of ''Gobipteryx minuta'' were found. Seven specimens in total were found, including two skeletons in the

redbeds Red beds (or redbeds) are sedimentary rocks, typically consisting of sandstone, siltstone, and shale, that are predominantly red in color due to the presence of ferric oxides. Frequently, these red-colored sedimentary strata locally contain th ...

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 period (geology), periods of the Cenozoic era (geology), Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spa ...

as well as the first confirmed

postcranial Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated sk ...

fossils of ''G. minuta'' found.

References

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