Balaur (dinosaur)
Encyclopedia
Balaur is a uniquely specialized
species
of carnivorous (theropod) dinosaur
. It lived in what is now Romania
during the latter part of the Late Cretaceous
. Balaur was described by scientists in August 2010, and was named after the balaur
, a dragon of Romanian folklore
. It is known from a single partial skeleton representing the type specimen. Having been described as a "beefy version of the predatory Velociraptor
", its name is Romanian
for 'stocky dragon'.
Seventy million years ago, world sea levels were higher, and the location where its fossils are found was an off-shore part of the European archipelago called Hațeg Island
. Unlike its other relatives within the dromaeosaur family, which includes Velociraptor
, Deinonychus
, and the four-winged Microraptor
, this raptor had not just one but two large, retractable, sickle-shaped claws on each foot, and its limbs were proportionally shorter and heavier than those of its other relatives. Given these and nearly twenty other derived
traits, the new genus
Balaur was created
for this one species. As with other dinosaurs from Hațeg, such as Magyarosaurus
, a dwarf sauropod, its aberrant features are argued to show the effects of its island habitat on its evolution.
). Its bones were shorter and heavier than those of other dromaeosaurs. While the feet of most dromaeosaurs bore a single, large "sickle claw" on the second toe which was held retracted off the ground, Balaur had large retractable sickle claws on both the first and second toes of each foot. In addition to its strange feet, Balaur is unique for its status of being the most complete nonavialan
theropod from the late Cretaceous of Europe. It also possesses a great number of additional autapomorphies, including a reduced and presumably nonfunctional third manual digit.
The partial skeleton was collected from the red floodplain mudstone
of the Sebeș
Formation of Romania. It consists of a variety of vertebrae, as well as much of pectoral and pelvic girdles
, and a large part of the limbs. It is the first reasonably complete and well-preserved theropod from the Late Cretaceous of Europe. During the Maastrichtian much of Europe was fragmented into islands, and a number of the animal's bizarre features are thought to be a result of the relatively isolated conditions imposed on many of the populations in this area. Species which are isolated on islands can be subject to the effects of genetic drift
and the founder effect
which can magnify the effect of mutations which might be diluted in a larger population. Other island effects such as Foster's rule
, which describes how small mainland species become larger and large mainland species become smaller, can take effect. Cretaceous Romania is known, for example, for its dwarf sauropods.
Phylogenetic analysis currently places Balaur closest to the Asiatic mainland species Velociraptor
to which it is similar in size, with Balaurs recovered skeletal elements suggesting an overall length of around 1.8–2.1 m (5.9–6.9 ft). Hence, in this case, Foster's effect is not evinced. Yet, when compared to its nearest relatives, some 20 unique features were observed, including a re-evolved functional first toe with a large claw that can be hyperextended, short and stocky feet and legs, and large muscle attachment areas on the pelvis which indicate that it was adapted for strength rather than speed. Csiki et al. describe this "novel body plan" as "a dramatic example of aberrant morphology developed in island-dwelling taxa."
by Dan Grigorescu, but the morphology of the arm was so unusual that scientists could not correctly combine them, mistaking them for the remains of a oviraptorosaur. The first partial skeleton was discovered in September 2009 in Romania, approximately 2.5 kilometers north of Sebeș, along the Sebeș river in the Sebeș Formation dating from the early Maastrichtian
, and was given the preliminary field number SbG/A-Sk1. Later it received the holotype
inventory number EME VP.313. The discovery was made by the geologist
and paleontologist Mátyás Vremir of the Transylvanian Museum Society of Cluj Napoca
who sent them for analysis to Zoltán Csiki of the University of Bucharest
. The findings were described on August 31, 2010, in the Proceedings of the National Academy of Sciences
. The 1997 specimens indicate an individual about 45% longer than the holotype; they were also found in a younger stratum
.
The generic name Balaur
(three syllables, stressed on the second /a/) is from the Romanian
word for a dragon of Romanian folklore
, while the specific epithet bondoc refers to the small, robust shape of the animal. As the balaur is a winged dragon, the name additionally hints at the close relation of Balaur to the birds within Panaves. Bondoc was chosen by the discoverers also because it is derived from the Turkish
bunduk, "small ball", thus alluding to the probable Asian origin of the ancestors of Balaur.
s in its limited island ecosystem, because no larger teeth have ever been found in Romania. He also believes that it likely used its double sickle claws for slashing prey, and that the atrophied state of its hands indicates that it probably did not use them to hunt. One of the original discoverers indicated that it "was probably more of a kickboxer than a sprinter" compared to Velociraptor, and was probably able to hunt larger animals than itself. However, the hunting behavior as well as its typical prey are not known.
Italian paleontologist Andrea Cau has speculated that the aberrant features present in Balaur may have been a result of this dromaeosaurid being omnivorous
or herbivorous
instead of carnivorous like typical dromaeosaurids. The lack of the third finger may be a sign of reduced predatory behavior and the robust first toe could be interpreted as a weight-supporting adaptation rather than a weapon. These characteristics are consistent with the relatively short, stocky limbs and wide, swept-back pubis, which may indicate enlarged intestines for digesting vegetation as well as reduced speed.
Autapomorphy
In cladistics, an autapomorphy is a distinctive anatomical feature, known as a derived trait, that is unique to a given terminal group. That is, it is found only in one member of a clade, but not found in any others or outgroup taxa, not even those most closely related to the group...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of carnivorous (theropod) dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
. It lived in what is now Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
during the latter part of the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
. Balaur was described by scientists in August 2010, and was named after the balaur
Balaur
A balaur is a creature in Romanian folklore, similar to a European dragon. A bălaur is quite large, has fins, feet, and is polycephalous...
, a dragon of Romanian folklore
Folklore of Romania
A feature of Romanian culture is the special relationship between folklore and the learned culture, determined by two factors. First, the rural character of the Romanian communities resulted in an exceptionally vital and creative traditional culture. Folk creations were the main literary genre...
. It is known from a single partial skeleton representing the type specimen. Having been described as a "beefy version of the predatory Velociraptor
Velociraptor
Velociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 million years ago during the later part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils...
", its name is Romanian
Romanian language
Romanian Romanian Romanian (or Daco-Romanian; obsolete spellings Rumanian, Roumanian; self-designation: română, limba română ("the Romanian language") or românește (lit. "in Romanian") is a Romance language spoken by around 24 to 28 million people, primarily in Romania and Moldova...
for 'stocky dragon'.
Seventy million years ago, world sea levels were higher, and the location where its fossils are found was an off-shore part of the European archipelago called Hațeg Island
Hateg Island
Hațeg Island was a large offshore island in the Tethys Sea during the Cretaceous period. It was situated in an area corresponding to the region around modern-day Hațeg, Romania...
. Unlike its other relatives within the dromaeosaur family, which includes Velociraptor
Velociraptor
Velociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 million years ago during the later part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils...
, Deinonychus
Deinonychus
Deinonychus was a genus of carnivorous dromaeosaurid dinosaur. There is one described species, Deinonychus antirrhopus. This 3.4 meter long dinosaur lived during the early Cretaceous Period, about 115–108 million years ago . Fossils have been recovered from the U.S...
, and the four-winged Microraptor
Microraptor
Microraptor is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China...
, this raptor had not just one but two large, retractable, sickle-shaped claws on each foot, and its limbs were proportionally shorter and heavier than those of its other relatives. Given these and nearly twenty other derived
Derived
In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...
traits, the new genus
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...
Balaur was created
Biological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
for this one species. As with other dinosaurs from Hațeg, such as Magyarosaurus
Magyarosaurus
Magyarosaurus is a genus of dwarf sauropod dinosaur from late Cretaceous Period in what is now Romania. It is one of the smallest-known adult sauropods, measuring only six meters in length. The type species is Magyarosaurus dacus...
, a dwarf sauropod, its aberrant features are argued to show the effects of its island habitat on its evolution.
Description
Balaur is a dromaeosaurid theropod dinosaur estimated to have lived about years ago in the late Cretaceous (MaastrichtianMaastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
). Its bones were shorter and heavier than those of other dromaeosaurs. While the feet of most dromaeosaurs bore a single, large "sickle claw" on the second toe which was held retracted off the ground, Balaur had large retractable sickle claws on both the first and second toes of each foot. In addition to its strange feet, Balaur is unique for its status of being the most complete nonavialan
Avialae
Avialae is a clade of dinosaurs containing their only living representatives, birds , and the most immediate extinct relatives of birds.-Competing definitions:...
theropod from the late Cretaceous of Europe. It also possesses a great number of additional autapomorphies, including a reduced and presumably nonfunctional third manual digit.
The partial skeleton was collected from the red floodplain mudstone
Mudstone
Mudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...
of the Sebeș
Sebes
Sebeș is a city in Alba County, central Romania, southern Transylvania.-Geography:The city lies on the Mureș River valley and it straddles the Sebeș river...
Formation of Romania. It consists of a variety of vertebrae, as well as much of pectoral and pelvic girdles
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
, and a large part of the limbs. It is the first reasonably complete and well-preserved theropod from the Late Cretaceous of Europe. During the Maastrichtian much of Europe was fragmented into islands, and a number of the animal's bizarre features are thought to be a result of the relatively isolated conditions imposed on many of the populations in this area. Species which are isolated on islands can be subject to the effects of genetic drift
Genetic drift
Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
and the founder effect
Founder effect
In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942, using existing theoretical work by those such as Sewall...
which can magnify the effect of mutations which might be diluted in a larger population. Other island effects such as Foster's rule
Foster's rule
Foster's rule is a principle in evolutionary biology stating that members of a species get smaller or bigger depending on the resources available in the environment. This is the core of the study of island biogeography. For example, it is known that pygmy mammoths evolved from normal mammoths on...
, which describes how small mainland species become larger and large mainland species become smaller, can take effect. Cretaceous Romania is known, for example, for its dwarf sauropods.
Phylogenetic analysis currently places Balaur closest to the Asiatic mainland species Velociraptor
Velociraptor
Velociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 million years ago during the later part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils...
to which it is similar in size, with Balaurs recovered skeletal elements suggesting an overall length of around 1.8–2.1 m (5.9–6.9 ft). Hence, in this case, Foster's effect is not evinced. Yet, when compared to its nearest relatives, some 20 unique features were observed, including a re-evolved functional first toe with a large claw that can be hyperextended, short and stocky feet and legs, and large muscle attachment areas on the pelvis which indicate that it was adapted for strength rather than speed. Csiki et al. describe this "novel body plan" as "a dramatic example of aberrant morphology developed in island-dwelling taxa."
Discovery
The first small bones belonging to Balaur bondoc consisted of six elements of the front limbs. Named specimens FGGUB R. 1580-1585, these were discovered in 1997 in RomaniaRomania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
by Dan Grigorescu, but the morphology of the arm was so unusual that scientists could not correctly combine them, mistaking them for the remains of a oviraptorosaur. The first partial skeleton was discovered in September 2009 in Romania, approximately 2.5 kilometers north of Sebeș, along the Sebeș river in the Sebeș Formation dating from the early Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
, and was given the preliminary field number SbG/A-Sk1. Later it received the holotype
Holotype
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...
inventory number EME VP.313. The discovery was made by the geologist
Geologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...
and paleontologist Mátyás Vremir of the Transylvanian Museum Society of Cluj Napoca
National Museum of Transylvanian History
The National Museum of Transylvanian History is a history and archaeology museum in the city of Cluj-Napoca, Romania. It features a permanent exhibition, as well as temporary exhibitions, the "Tezaur" exhibition, and Pharmacy Historical collection—this last opened in the Hintz House, an...
who sent them for analysis to Zoltán Csiki of the University of Bucharest
University of Bucharest
The University of Bucharest , in Romania, is a university founded in 1864 by decree of Prince Alexander John Cuza to convert the former Saint Sava Academy into the current University of Bucharest.-Presentation:...
. The findings were described on August 31, 2010, in the Proceedings of the National Academy of Sciences
Proceedings of the National Academy of Sciences
The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences...
. The 1997 specimens indicate an individual about 45% longer than the holotype; they were also found in a younger stratum
Stratum
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
.
The generic name Balaur
Balaur
A balaur is a creature in Romanian folklore, similar to a European dragon. A bălaur is quite large, has fins, feet, and is polycephalous...
(three syllables, stressed on the second /a/) is from the Romanian
Romanian language
Romanian Romanian Romanian (or Daco-Romanian; obsolete spellings Rumanian, Roumanian; self-designation: română, limba română ("the Romanian language") or românește (lit. "in Romanian") is a Romance language spoken by around 24 to 28 million people, primarily in Romania and Moldova...
word for a dragon of Romanian folklore
Folklore of Romania
A feature of Romanian culture is the special relationship between folklore and the learned culture, determined by two factors. First, the rural character of the Romanian communities resulted in an exceptionally vital and creative traditional culture. Folk creations were the main literary genre...
, while the specific epithet bondoc refers to the small, robust shape of the animal. As the balaur is a winged dragon, the name additionally hints at the close relation of Balaur to the birds within Panaves. Bondoc was chosen by the discoverers also because it is derived from the Turkish
Turkish language
Turkish is a language spoken as a native language by over 83 million people worldwide, making it the most commonly spoken of the Turkic languages. Its speakers are located predominantly in Turkey and Northern Cyprus with smaller groups in Iraq, Greece, Bulgaria, the Republic of Macedonia, Kosovo,...
bunduk, "small ball", thus alluding to the probable Asian origin of the ancestors of Balaur.
Behavior
Little is known about the behavior of Balaur, but Csiki speculates that it may have been one of the apex predatorApex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
s in its limited island ecosystem, because no larger teeth have ever been found in Romania. He also believes that it likely used its double sickle claws for slashing prey, and that the atrophied state of its hands indicates that it probably did not use them to hunt. One of the original discoverers indicated that it "was probably more of a kickboxer than a sprinter" compared to Velociraptor, and was probably able to hunt larger animals than itself. However, the hunting behavior as well as its typical prey are not known.
Italian paleontologist Andrea Cau has speculated that the aberrant features present in Balaur may have been a result of this dromaeosaurid being omnivorous
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...
or herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
instead of carnivorous like typical dromaeosaurids. The lack of the third finger may be a sign of reduced predatory behavior and the robust first toe could be interpreted as a weight-supporting adaptation rather than a weapon. These characteristics are consistent with the relatively short, stocky limbs and wide, swept-back pubis, which may indicate enlarged intestines for digesting vegetation as well as reduced speed.
External links
- "'Stocky dragon' dinosaur terrorized Late Cretaceous Europe" article from PhysOrg.com