Azhdarcho
Encyclopedia
Azhdarcho is a genus of pterodactyloid pterosaur
from the late Cretaceous
Period of the Bissekty Formation
(middle Turonian
stage, about 92 million years ago) of Uzbekistan
. It is known from fragmentary remains including the distinctive, elongated neck vertebrae that characterizes members of the family Azhdarchidae
, which also includes such giant pterosaurs as Quetzalcoatlus
. The name Azhdarcho comes from the Uzbek
word azhdarkho adʒˈdarχɒ, the name of a dragon in Uzbek
mythology. The type species
is Azhdarcho lancicollis. The specific epithet lancicollis is derived from the Latin
words lancea (meaning "lance" or "spear") and collum ("neck").
remains of Azhdarcho were recovered in the Kyzyl Kum
desert (from the Taykarshinskaya unit of the Bissekty Formation
) by Lev A. Nesov during expeditions to Central Asia in 1974-1981. The type specimen, given the catalog number TsNIGRmuzey 1/11915, consists of an anterior neck vertebra. Twelve paratype
s were referred, including several other neck vertebrae, elements from the wing and leg, and pieces of the jaw. These specimens, along with other vertebrate fossils collected during the expeditions, were deposited at the F.N. Chernyshev Central Geologic Exploration Museum in St. Petersberg.
In his description of the type specimen of Azhdarcho lancicollis, Nesov noted its distinctive neck vertebrae, which are extremely elongated and round in cross section at mid-length. He pointed out similar characteristics in several other pterosaurs, and used them to erect the new subfamily Azhdarchinae, within the Pteranodontidae
. Nesov also referred Quetzalcoatlus and Arambourgiania
(then known as Titanopteryx) to this subfamily, which was subsequently re-classified as the family
Azhdarchidae
. He also suggested that similar, thin-walled pterosaur bones from the Lance Formation
of Wyoming
could be assigned to a species of Azhdarcho, using this as evidence of commonalities between the fauna of Late Cretaceous central Asia and western North America. However, subsequent research has not followed this suggestion, and A. lancicollis is the only currently recognized species of Azhdarcho.
, with their long necks allowing them to scoop prey from the water's surface and small depths without needing to dive. However, recent research has shown that skimming requires more energy and anatomical specializations than previously thought, and that large pterosaurs like Azhdarcho probably were not capable of skimming. The long neck would also have allowed azhdarchids to hunt for food in the water or on the bottom while swimming, or to hunt poorly-flying vertebrates in the air, though Nesov also suggested that the animal would have needed stable weather conditions to fly well, and suggested azhdarchid habitats needed to be dominated by even, mild winds.
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
from the late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Period of the Bissekty Formation
Bissekty Formation
The Bissekty Formation is situated in the Kyzyl Kum desert of Uzbekistan, and dates from the late Cretaceous Period. Laid down in the early the Turonian to Coniacian stages, it is dated to about 90-85 ma .The Bissekty Formation is characterised by a mix of marine, brackish, freshwater, and...
(middle Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
stage, about 92 million years ago) of Uzbekistan
Uzbekistan
Uzbekistan , officially the Republic of Uzbekistan is a doubly landlocked country in Central Asia and one of the six independent Turkic states. It shares borders with Kazakhstan to the west and to the north, Kyrgyzstan and Tajikistan to the east, and Afghanistan and Turkmenistan to the south....
. It is known from fragmentary remains including the distinctive, elongated neck vertebrae that characterizes members of the family Azhdarchidae
Azhdarchidae
Azhdarchidae is a family of pterosaurs known primarily from the late Cretaceous Period, though an isolated vertebrae apparently from an azhdarchid is known from the early Cretaceous as well...
, which also includes such giant pterosaurs as Quetzalcoatlus
Quetzalcoatlus
Quetzalcoatlus was a pterodactyloid pterosaur known from the Late Cretaceous of North America , and one of the largest known flying animals of all time. It was a member of the Azhdarchidae, a family of advanced toothless pterosaurs with unusually long, stiffened necks...
. The name Azhdarcho comes from the Uzbek
Uzbek language
Uzbek is a Turkic language and the official language of Uzbekistan. It has about 25.5 million native speakers, and it is spoken by the Uzbeks in Uzbekistan and elsewhere in Central Asia...
word azhdarkho adʒˈdarχɒ, the name of a dragon in Uzbek
Uzbeks
The Uzbeks are a Turkic ethnic group in Central Asia. They comprise the majority population of Uzbekistan, and large populations can also be found in Afghanistan, Tajikstan, Kyrgyzstan, Turkmenistan, Kazakhstan, Russia, Pakistan, Mongolia and the Xinjiang Uyghur Autonomous Region of China...
mythology. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Azhdarcho lancicollis. The specific epithet lancicollis is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
words lancea (meaning "lance" or "spear") and collum ("neck").
History
The fossilFossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
remains of Azhdarcho were recovered in the Kyzyl Kum
Kyzyl Kum
The Kyzyl Kum , also called Qyzylqum, is the 11th largest desert in the world. Its name means Red Sand in Turkic languages. It is located in Central Asia in the doab between the rivers Amu Darya and Syr Darya, and is divided between Kazakhstan, Uzbekistan and Turkmenistan...
desert (from the Taykarshinskaya unit of the Bissekty Formation
Bissekty Formation
The Bissekty Formation is situated in the Kyzyl Kum desert of Uzbekistan, and dates from the late Cretaceous Period. Laid down in the early the Turonian to Coniacian stages, it is dated to about 90-85 ma .The Bissekty Formation is characterised by a mix of marine, brackish, freshwater, and...
) by Lev A. Nesov during expeditions to Central Asia in 1974-1981. The type specimen, given the catalog number TsNIGRmuzey 1/11915, consists of an anterior neck vertebra. Twelve paratype
Paratype
Paratype is a technical term used in the scientific naming of species and other taxa of organisms. The exact meaning of the term paratype when it is used in zoology is not the same as the meaning when it is used in botany...
s were referred, including several other neck vertebrae, elements from the wing and leg, and pieces of the jaw. These specimens, along with other vertebrate fossils collected during the expeditions, were deposited at the F.N. Chernyshev Central Geologic Exploration Museum in St. Petersberg.
In his description of the type specimen of Azhdarcho lancicollis, Nesov noted its distinctive neck vertebrae, which are extremely elongated and round in cross section at mid-length. He pointed out similar characteristics in several other pterosaurs, and used them to erect the new subfamily Azhdarchinae, within the Pteranodontidae
Pteranodontidae
The Pteranodontidae are a family of large pterosaurs of the Cretaceous Period of North America.The family was named in 1876 by Othniel Charles Marsh....
. Nesov also referred Quetzalcoatlus and Arambourgiania
Arambourgiania
Arambourgiania is a pterosaur from the Late Cretaceous of Jordan. It was one of the largest members of this group.In the early forties, a railway worker during repairs on the Amman-Damascus railroad near Russeifa found a two feet long fossil bone...
(then known as Titanopteryx) to this subfamily, which was subsequently re-classified as the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Azhdarchidae
Azhdarchidae
Azhdarchidae is a family of pterosaurs known primarily from the late Cretaceous Period, though an isolated vertebrae apparently from an azhdarchid is known from the early Cretaceous as well...
. He also suggested that similar, thin-walled pterosaur bones from the Lance Formation
Lance Formation
The Lance Formation is a division of Late Cretaceous rocks in the western United States. Named after Lance Creek, Wyoming, the microvertebrate fossils and dinosaurs represent important components of the latest Mesozoic vertebrate faunas...
of Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
could be assigned to a species of Azhdarcho, using this as evidence of commonalities between the fauna of Late Cretaceous central Asia and western North America. However, subsequent research has not followed this suggestion, and A. lancicollis is the only currently recognized species of Azhdarcho.
Paleoecology
In the original description of Azhdarcho, Nesov noted that because of the way the vertebrae articulated, the pterosaur would have had very limited flexibility in the neck. Azhdarcho could not rotate its neck at all, though it could flex the neck vertically to a certain degree. Nesov suggested that pterosaurs like Azhdarcho may have fed in a manner similar to the modern SkimmerSkimmer
The Skimmers, Rynchopidae, are a small family of tern-like birds in the order Charadriiformes, which also includes the waders, gulls and auks. The family comprises three species found in South Asia, Africa, and the Americas....
, with their long necks allowing them to scoop prey from the water's surface and small depths without needing to dive. However, recent research has shown that skimming requires more energy and anatomical specializations than previously thought, and that large pterosaurs like Azhdarcho probably were not capable of skimming. The long neck would also have allowed azhdarchids to hunt for food in the water or on the bottom while swimming, or to hunt poorly-flying vertebrates in the air, though Nesov also suggested that the animal would have needed stable weather conditions to fly well, and suggested azhdarchid habitats needed to be dominated by even, mild winds.