Dendrorhynchoides
Encyclopedia
Dendrorhynchoides was a genus
of anurognathid
pterosaur
from the Early Cretaceous
(early Aptian
) Yixian Formation
, near Beipiao
, Chaoyang, Liaoning
, China
. The holotype was found in the Jianshangou Bed of the Yixian Formation, dated to about 124.5 million years old.
The genus was in 1998 first named Dendrorhynchus by Ji Shu'an and Ji Qiang, but that name proved to be preoccupied
by a nemertean parasitic worm named in 1920 by David Keilin
. It was therefore renamed in 1999. The type species
is Dendrorhynchoides curvidentatus. The genus name is derived from Greek dendron, "tree" and rhynkhos, "snout" in reference to it being assumed a tree-dweller and presumed a close relative of Rhamphorhynchus. The specific name means "curved-toothed" in Latin
.
GMV2128, a fossil
originally discovered around 1995 and obtained by science from illegal fossil dealers who first prepared it. It consists of a near-complete skeleton of a subadult individual and is crushed. Most elements are present, exceptions include the sternum, the tail end, sacrals and the fourth phalanx of the wing finger.
Of the type specimen, most parts of the skull have become detached so that its shape is difficult to determine, but it was generally short and broad. Eleven teeth have been preserved scattered throughout the matrix, that are recurved with a broader base and have a length of three millimetres. The authors identified lower jaws with a preserved length of fifteen millimetres. The cervical vertebrae are short and broad. Six dorsal vertebrae have been preserved, nine ribs and six belly ribs at the left side. The tail has a preserved length of five centimetres, but part of this is accounted for by a section that might have been added to enhance the value of the fossil. The tail vertebrae at the base, the authenticity of which is certain, are short.
The wings are relatively short. The humerus
is robustly built but elongated with a length of 27 millimetres. The ulna
is 35.5 millimetres long. The metacarpals are short with seven millimetres length for the first three, 9.3 millimetres for the fourth wing-bearing metacarpal. The first three fingers are well developed with the first having an elongated first phalanx. They bear short but sharp claws. The first phalanx of the fourth, wing, finger has a length of 44.5, the second of 35.6 millimetres. The size of the third cannot be established because of damage. A short and slender pteroid, 5.9 millimetres long, points towards the elbow. The wingspan is about forty centimetres, making Dendrorhynchoides one of the smallest known pterosaurs
The tibia
has a length of 26.7 millimetres and is about a third longer than the femur
. The fibula is reduced, reaching about half-way downwards along the tibia shaft. The foot is long with the metatarsals having a length of 12.1 millimetres. The fifth toe is elongated.
Because of the presumed long tail, the authors rejected a placement within the Anurognathidae and classified it instead as a long-tailed rhamphorhynchid
, mainly in view of the general long bone proportions. It was in 2000 identified as an anurognathid, and it was confirmed that the fossil had been doctored prior to its description.
A cladistic analysis by Alexander Kellner
in 2003 had the same outcome, Dendrorhynchoides being found to form an anurognathid clade
with Batrachognathus
and Jeholopterus
, that he named the Asiaticognathidae. An analysis by Lü Junchang in 2006 resolved the relations even further, finding Dendrorhynchoides to be the sister taxon of clade formed by the other two asiaticognathid species.
The describers postulated a tree-dwelling lifestyle for Dendrorhynchoides as an insectivore.
In 2010 a second specimen, of a juvenile, was announced, GLGMV 0002, that proved that a more elongated tail was present after all, albeit not so long as the faked tail of the holotype: about 85% of femur length.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of anurognathid
Anurognathid
The Anurognathidae were a group of small pterosaurs, with short tails or tailless, that lived in Europe and Asia during the Jurassic and early Cretaceous periods...
pterosaur
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 Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
(early Aptian
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous epoch or series and encompasses the time from 125.0 ± 1.0 Ma to 112.0 ± 1.0 Ma , approximately...
) Yixian Formation
Yixian Formation
The Yixian Formation is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans 11 million years during the early Cretaceous period...
, near Beipiao
Beipiao
Beipiao is a city in Chaoyang prefecture, Liaoning province, in Northeast China. It has a population of 202,807. The main industry in the area is coal mining. With vertical shafts of almost 1000m, these are some of the deepest coal mines in China. The coal produced is used for coking...
, Chaoyang, Liaoning
Liaoning
' is a province of the People's Republic of China, located in the northeast of the country. Its one-character abbreviation is "辽" , a name taken from the Liao River that flows through the province. "Níng" means "peace"...
, China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
. The holotype was found in the Jianshangou Bed of the Yixian Formation, dated to about 124.5 million years old.
The genus was in 1998 first named Dendrorhynchus by Ji Shu'an and Ji Qiang, but that name proved to be preoccupied
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
by a nemertean parasitic worm named in 1920 by David Keilin
David Keilin
David Keilin FRS was an entomologist, among other things.His family returned to Warsaw early in his youth. He did not attend school until age ten due to ill health and asthma. Only seven years later, in 1904, he enrolled in the University of Liège...
. It was therefore renamed in 1999. 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 Dendrorhynchoides curvidentatus. The genus name is derived from Greek dendron, "tree" and rhynkhos, "snout" in reference to it being assumed a tree-dweller and presumed a close relative of Rhamphorhynchus. The specific name means "curved-toothed" in 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...
.
Description
The genus is based on holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
GMV2128, a fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
originally discovered around 1995 and obtained by science from illegal fossil dealers who first prepared it. It consists of a near-complete skeleton of a subadult individual and is crushed. Most elements are present, exceptions include the sternum, the tail end, sacrals and the fourth phalanx of the wing finger.
Of the type specimen, most parts of the skull have become detached so that its shape is difficult to determine, but it was generally short and broad. Eleven teeth have been preserved scattered throughout the matrix, that are recurved with a broader base and have a length of three millimetres. The authors identified lower jaws with a preserved length of fifteen millimetres. The cervical vertebrae are short and broad. Six dorsal vertebrae have been preserved, nine ribs and six belly ribs at the left side. The tail has a preserved length of five centimetres, but part of this is accounted for by a section that might have been added to enhance the value of the fossil. The tail vertebrae at the base, the authenticity of which is certain, are short.
The wings are relatively short. The humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
is robustly built but elongated with a length of 27 millimetres. The ulna
Ulna
The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...
is 35.5 millimetres long. The metacarpals are short with seven millimetres length for the first three, 9.3 millimetres for the fourth wing-bearing metacarpal. The first three fingers are well developed with the first having an elongated first phalanx. They bear short but sharp claws. The first phalanx of the fourth, wing, finger has a length of 44.5, the second of 35.6 millimetres. The size of the third cannot be established because of damage. A short and slender pteroid, 5.9 millimetres long, points towards the elbow. The wingspan is about forty centimetres, making Dendrorhynchoides one of the smallest known pterosaurs
The tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
has a length of 26.7 millimetres and is about a third longer than the femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
. The fibula is reduced, reaching about half-way downwards along the tibia shaft. The foot is long with the metatarsals having a length of 12.1 millimetres. The fifth toe is elongated.
Because of the presumed long tail, the authors rejected a placement within the Anurognathidae and classified it instead as a long-tailed rhamphorhynchid
Rhamphorhynchidae
Rhamphorhynchidae is a group of early "rhamphorhynchoid" pterosaurs named after Rhamphorhynchus, that lived in the Late Jurassic. The family Rhamphorhynchidae was named in 1870 by Harry Govier Seeley.-Classification:...
, mainly in view of the general long bone proportions. It was in 2000 identified as an anurognathid, and it was confirmed that the fossil had been doctored prior to its description.
A cladistic analysis by Alexander Kellner
Alexander Kellner
Alexander Wilhelm Armin Kellner is a Liechtensteinian/Brazilian paleontologist, a leading expert in the field of the study of pterosaurs....
in 2003 had the same outcome, Dendrorhynchoides being found to form an anurognathid clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
with Batrachognathus
Batrachognathus
Batrachognathus is an extinct genus of "rhamphorhynchoid" pterosaur from the Late Jurassic Karabastau Svita of the central Asian republic of Kazakhstan....
and Jeholopterus
Jeholopterus
Jeholopterus was a small anurognathid pterosaur from the Daohugou Beds of northeastern China , between 168 and 152 million years ago), preserved with hair and skin remains.-Naming:...
, that he named the Asiaticognathidae. An analysis by Lü Junchang in 2006 resolved the relations even further, finding Dendrorhynchoides to be the sister taxon of clade formed by the other two asiaticognathid species.
The describers postulated a tree-dwelling lifestyle for Dendrorhynchoides as an insectivore.
In 2010 a second specimen, of a juvenile, was announced, GLGMV 0002, that proved that a more elongated tail was present after all, albeit not so long as the faked tail of the holotype: about 85% of femur length.
External links
- Dendrorhynchoides in The Pterosauria