Bruhathkayosaurus
Encyclopedia
Bruhathkayosaurus might have been the largest dinosaur
that ever lived. The accuracy of this claim, however, has been mired in controversy and debate. All the estimates are based on Yadagiri and Ayyasami's 1989 paper, which announced the find.
The authors originally classified the dinosaur as a theropod
, a member of a large group of biped
al, mostly carnivorous
dinosaurs that includes Tyrannosaurus
, but several unpublished opinions beginning in 1995 suggested that the remains actually belonged to a sauropod (probably a titanosaur
), a member of a very different group of quadruped
al, herbivorous
dinosaurs with long necks and tails such as Brachiosaurus
. In 2006, the first published reference to Bruhathkayosaurus as a sauropod appeared in a survey of Malagasy
vertebrate
s by David Krause and colleagues.
Until the remains are properly described, the validity of the genus and any size estimates will be questionable.
, specifically in the Tiruchirappalli district of Tamil Nadu
, to the northeast of Kallamedu village. It was recovered from the rocks of the Kallemedu Formation, which are dated to the Maastrichtian faunal stage
of the late Cretaceous
period. It lived toward the end of Mesozoic
Era, about 70 million years ago. The fossilized remains include hip bones (the ilium
and ischium), part of a leg bone (femur
), a shin bone (tibia
), a forearm (radius
) and a tail bone (part of a vertebra, specifically a platycoelous caudal centrum). The remains were originally classified as belonging to a carnosaur
. The name chosen, Bruhathkayosaurus, is derived from bruhath (misspelled Sanskrit
brhat (बृहत), huge, or heavy), and kāya (काय) (body); and the Greek
sauros (lizard
).
has only one known species
, Bruhathkayosaurus matleyi. The species is represented by the holotype
specimen GSI PAL/SR/20, which was described by Yadagiri and Ayyasami in 1989 (not 1987, as some sources indicate). It was originally classified as a carnosaur
(like Allosaurus
), of an unknown (incertae sedis) family
. It was later recognized as a sauropod
.
The original publication described little in the way of diagnostic characteristics and was only supported by a few line drawings. This has led to speculation that the bones might actually be petrified wood
, akin to the way the original discoverers of Sauroposeidon
initially believed their find to be fossil
ized tree trunks.
) of Bruhathkayosaurus is 2 m (6.6 ft) long. This is 29 percent larger than the tibia of Argentinosaurus, which is only 1.55 m (5.08 ft) long. Comparing the bones in the upper forelimb gives a similar result. While the humerus
of Bruhathkayosaurus is incomplete, it is extrapolated to have been 2.34 m (7.68 ft) long. This is 30 percent larger than the humerus of Argentinosaurus, which is 1.81 m (5.94 ft) long.
No total body size estimates for Bruhathkayosaurus have been published, but paleontologists and researchers have posted tentative estimates on the Internet
. One early estimate by Mickey Mortimer estimated that Bruhathkayosaurus could have reached 40–44 m (130–145 ft) in length and to have weighed 175–220 tons. However, Mortimer later retracted these estimates, reducing his estimated length of Bruhathkayosaurus to 28–34 m (90–110 ft), and declined to provide a new weight estimate, describing the older mass estimates as inaccurate. In a May 2008 article for the weblog Sauropod Vertebra Picture of the Week, paleontologist Matt Wedel used a comparison with Argentinosaurus and calculated the weight of Bruhathkayosaurus at up to 139 tons.
By comparison, the titanosaur Argentinosaurus is estimated to have reached 34.6 m (114 ft) in length, and to have weighed 80–100 tons. Another huge titanosaurid, Paralititan
, was probably 31.9 m (105 ft) long, and weighed 65–80 tons. All of these sauropods are known only from partial or fragmentary remains, so the size estimates are uncertain. Length is calculated by comparing existing bones to the bones of similar dinosaurs, which are known from more complete skeletons and scaling them up isometrically. However, such extrapolation can never be more than an educated guess and the length of the tail, in particular, is often hard to judge. Determining mass is even more difficult, because little evidence of soft tissues survives in the fossil record. In addition, isometric
scaling is based on the assumption that body proportions remain the same, which is not necessarily the case. In particular, the proportions of the titanosaurs are not well known, due to a limited number of relatively complete specimens.
If the size estimates for Bruhathkayosaurus are accurate, the only other animal approaching its size would be the Blue Whale
. Mature Blue Whales can reach 30 m (98 ft) in length, which is a little shorter than Bruhathkayosaurus, but the record-holder Blue Whale weighed in at 176 tons, which is probably heavier than Bruhathkayosaurus.
Among the dinosaurs, only another poorly known specimen may approach or exceed Bruhathkayosaurus in size. Edward Drinker Cope
's Amphicoelias
fragillimus would have been longer, reaching 56–62 m (185–200 ft) in length, but it was a slender diplodocid
, weighing only 120 tons. However, the only bone recovered (a massive vertebra) is now missing, and only a description and drawing of the specimen remain.
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...
that ever lived. The accuracy of this claim, however, has been mired in controversy and debate. All the estimates are based on Yadagiri and Ayyasami's 1989 paper, which announced the find.
The authors originally classified the dinosaur as a theropod
Theropoda
Theropoda is both a suborder of bipedal saurischian dinosaurs, and a clade consisting of that suborder and its descendants . Dinosaurs belonging to the suborder theropoda were primarily carnivorous, although a number of theropod groups evolved herbivory, omnivory, and insectivory...
, a member of a large group of biped
Biped
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs, or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning "two feet"...
al, mostly carnivorous
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
dinosaurs that includes Tyrannosaurus
Tyrannosaurus
Tyrannosaurus meaning "tyrant," and sauros meaning "lizard") is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other...
, but several unpublished opinions beginning in 1995 suggested that the remains actually belonged to a sauropod (probably a titanosaur
Titanosaur
Titanosaurs were a diverse group of sauropod dinosaurs, which included Saltasaurus and Isisaurus. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus and Paralititan — which some believe have weighed up to 100 tonnes...
), a member of a very different group of quadruped
Quadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
al, 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...
dinosaurs with long necks and tails such as Brachiosaurus
Brachiosaurus
Brachiosaurus is a genus of sauropod dinosaur from the Jurassic Morrison Formation of North America. It was first described by Elmer S. Riggs in 1903 from fossils found in the Grand River Canyon of western Colorado, in the United States. Riggs named the dinosaur Brachiosaurus altithorax,...
. In 2006, the first published reference to Bruhathkayosaurus as a sauropod appeared in a survey of Malagasy
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s by David Krause and colleagues.
Until the remains are properly described, the validity of the genus and any size estimates will be questionable.
Discovery
Bruhathkayosaurus was found near the southern tip of IndiaIndia
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, specifically in the Tiruchirappalli district of Tamil Nadu
Tamil Nadu
Tamil Nadu is one of the 28 states of India. Its capital and largest city is Chennai. Tamil Nadu lies in the southernmost part of the Indian Peninsula and is bordered by the union territory of Pondicherry, and the states of Kerala, Karnataka, and Andhra Pradesh...
, to the northeast of Kallamedu village. It was recovered from the rocks of the Kallemedu Formation, which are dated to the Maastrichtian faunal stage
Faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...
of 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. It lived toward the end of Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
Era, about 70 million years ago. The fossilized remains include hip bones (the ilium
Ilium (bone)
The ilium is the uppermost and largest bone of the pelvis, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium.The name comes from the Latin ,...
and ischium), part of a leg bone (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...
), a shin bone (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....
), a forearm (radius
Radius (bone)
The radius is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna, which exceeds it in length and size. It is a long bone, prism-shaped and slightly curved longitudinally...
) and a tail bone (part of a vertebra, specifically a platycoelous caudal centrum). The remains were originally classified as belonging to a carnosaur
Carnosauria
Carnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
. The name chosen, Bruhathkayosaurus, is derived from bruhath (misspelled Sanskrit
Sanskrit
Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...
brhat (बृहत), huge, or heavy), and kāya (काय) (body); and the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
sauros (lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
).
Classification
The Bruhathkayosaurus genusGenus
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...
has only one known 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...
, Bruhathkayosaurus matleyi. The species is represented by 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...
specimen GSI PAL/SR/20, which was described by Yadagiri and Ayyasami in 1989 (not 1987, as some sources indicate). It was originally classified as a carnosaur
Carnosauria
Carnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
(like Allosaurus
Allosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
), of an unknown (incertae sedis) 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...
. It was later recognized as a sauropod
Sauropoda
Sauropoda , or the sauropods , are an infraorder of saurischian dinosaurs. They had long necks, long tails, small heads , and thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land...
.
The original publication described little in the way of diagnostic characteristics and was only supported by a few line drawings. This has led to speculation that the bones might actually be petrified wood
Petrified wood
Petrified wood is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree having turned completely into stone by the process of permineralization...
, akin to the way the original discoverers of Sauroposeidon
Sauroposeidon
Sauroposeidon is a genus of sauropod dinosaur known from four neck vertebrae that were found in the southeastern portion of the US state of Oklahoma. The fossils were found in rocks dating to the Early Cretaceous, a period when the sauropods of North America had diminished in both size and...
initially believed their find to be fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
ized tree trunks.
Size estimates
According to the published description, the shin bone (tibiaTibia
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....
) of Bruhathkayosaurus is 2 m (6.6 ft) long. This is 29 percent larger than the tibia of Argentinosaurus, which is only 1.55 m (5.08 ft) long. Comparing the bones in the upper forelimb gives a similar result. While the humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
of Bruhathkayosaurus is incomplete, it is extrapolated to have been 2.34 m (7.68 ft) long. This is 30 percent larger than the humerus of Argentinosaurus, which is 1.81 m (5.94 ft) long.
No total body size estimates for Bruhathkayosaurus have been published, but paleontologists and researchers have posted tentative estimates on the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
. One early estimate by Mickey Mortimer estimated that Bruhathkayosaurus could have reached 40–44 m (130–145 ft) in length and to have weighed 175–220 tons. However, Mortimer later retracted these estimates, reducing his estimated length of Bruhathkayosaurus to 28–34 m (90–110 ft), and declined to provide a new weight estimate, describing the older mass estimates as inaccurate. In a May 2008 article for the weblog Sauropod Vertebra Picture of the Week, paleontologist Matt Wedel used a comparison with Argentinosaurus and calculated the weight of Bruhathkayosaurus at up to 139 tons.
By comparison, the titanosaur Argentinosaurus is estimated to have reached 34.6 m (114 ft) in length, and to have weighed 80–100 tons. Another huge titanosaurid, Paralititan
Paralititan
Paralititan was a giant titanosaurian sauropod dinosaur genus discovered in coastal deposits in the Upper Cretaceous Bahariya Formation of Egypt. The fossil represents the first tetrapod reported from the Bahariya Formation since 1935. Its 1.69 meter long humerus is longer than that of any...
, was probably 31.9 m (105 ft) long, and weighed 65–80 tons. All of these sauropods are known only from partial or fragmentary remains, so the size estimates are uncertain. Length is calculated by comparing existing bones to the bones of similar dinosaurs, which are known from more complete skeletons and scaling them up isometrically. However, such extrapolation can never be more than an educated guess and the length of the tail, in particular, is often hard to judge. Determining mass is even more difficult, because little evidence of soft tissues survives in the fossil record. In addition, isometric
Isometric
The term isometric comes from the Greek for "having equal measurement".isometric may mean:* Isometric projection , a method for the visual representation of three-dimensional objects in two dimensions; a form of orthographic projection, or more specifically, an axonometric projection.* Isometry and...
scaling is based on the assumption that body proportions remain the same, which is not necessarily the case. In particular, the proportions of the titanosaurs are not well known, due to a limited number of relatively complete specimens.
If the size estimates for Bruhathkayosaurus are accurate, the only other animal approaching its size would be the Blue Whale
Blue Whale
The blue whale is a marine mammal belonging to the suborder of baleen whales . At in length and or more in weight, it is the largest known animal to have ever existed....
. Mature Blue Whales can reach 30 m (98 ft) in length, which is a little shorter than Bruhathkayosaurus, but the record-holder Blue Whale weighed in at 176 tons, which is probably heavier than Bruhathkayosaurus.
Among the dinosaurs, only another poorly known specimen may approach or exceed Bruhathkayosaurus in size. Edward Drinker Cope
Edward Drinker Cope
Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...
's Amphicoelias
Amphicoelias
Amphicoelias is a genus of herbivorous sauropod dinosaur that includes what may be the largest dinosaur ever discovered, A. fragillimus. Based on surviving descriptions of a single fossil bone, A. fragillimus may have been the longest known vertebrate at in length, and may have had a mass of up...
fragillimus would have been longer, reaching 56–62 m (185–200 ft) in length, but it was a slender diplodocid
Diplodocid
Diplodocids, or members of the family Diplodocidae , are a group of sauropod dinosaurs. The family includes some of the longest creatures ever to walk the earth, including Diplodocus and Supersaurus, which may have reached lengths of up to .-Description:While still massive, when compared to the...
, weighing only 120 tons. However, the only bone recovered (a massive vertebra) is now missing, and only a description and drawing of the specimen remain.
External links
- Report on the initial description from the Dinosaur Mailing List.