Rapetosaurus
Encyclopedia
Rapetosaurus is a genus
of sauropod dinosaur
that lived in Madagascar
from 70 to 65 million years ago, at the end of the Cretaceous
Period. Only one species
(R. krausei) has been identified.
Like other sauropods, Rapetosaurus was a quadrupedal herbivore
; it is calculated to have reached lengths of 15 metres (49 ft).
Rapetosaurus was a fairly typical sauropod, with a short and slender tail
, a very long neck
and a huge, elephant
-like body. Its head resembles the head of a diplodocid
, with a long, narrow snout and nostrils on the top of its skull
. It was a herbivore and its small, pencil-like teeth were good for ripping the leaves off trees but not for chewing.
It was fairly modest in size, for a titanosaur
. The juvenile specimen measured 8 metres (26 ft) from head to tail, and "probably weighed about as much as an elephant", according to Kristina Curry Rogers. An adult would have been about twice as long (15 meters (49 ft) in length) which is still less than half the length of its gigantic kin, like Argentinosaurus
and Paralititan
.
, which killed almost all the dinosaur
s about 65 million years ago.
had been recovered with an almost perfectly intact skeleton
, complete with skull
. It has helped to clarify some difficult, century-old classification issues, among this large group of sauropod dinosaur
s and provides a good baseline for the reconstruction of other titanosaur
s that are known only from partial fossil
ized remains.
The discovery was published in 2001 by Kristina Curry Rogers
and Catherine A. Forster in the scientific journal Nature
. The nearly-complete skeleton is that of a juvenile and partial remains from three other individuals were also recovered.
specimen), another partial skull, a juvenile skeleton missing only a few tail vertebrae, and an unrelated vertebra. The juvenile skeleton, in particular, is the most complete titanosaur skeleton ever recovered and the only one with a head still attached to the body.
The fossilized remains were found in the Mahajanga basin in northwest Madagascar
, not far from the port city of Mahajanga
. They were recovered from a layer of sandstone known as the Anembalemba Member, which is part of the Maevarano Formation
. The rock formation has been dated to the Maastrichtian
stage
of the late Cretaceous, which means the fossilized bones are about 70 million years old.
They were found by a field team from the State University of New York at Stony Brook
with the assistance of the local Universite d'Antananarivo. The team leader, David Krause, had been excavating fossils from the site since 1993.
discoveries for Krause and his team. As well as dinosaurs, fossils of fish
es, frog
s, turtle
s, snake
s, crocodile
s, bird
s, and mammal
s have been unearthed. Significant finds include:
The titanosaurs are the largest group of sauropods but are poorly represented in the fossil record. Other groups of sauropods, even small families like the brachiosaurids, are known from more complete remains. Until the discovery of Rapetosaurus, the 30 or so genera
were represented by just a few bones, a partial skeleton or a skull. The first titanosaur
, discovered in 1887, is still only known from a partial skeleton.
This has made it difficult to determine not just the relationship between different genera of titanosaur but even how the titanosaurs are related to other, higher-level groups like the macronaria
ns (the group of "big nostril" sauropods, which include the titanosaurs, the nemegosaurids and the brachiosaurids). The whole taxon
has been used as a dumping ground, with many genera labeled as incertae sedis (belonging to an unknown group), because not enough is known about them to classify them any further.
The Diplodocus-like skull has demonstrated that titanosaur skulls vary more than was previously believed. Most paleontologists believed that titanosaurs had box-like skulls with the nostrils midway up the snout, like the Camarasaurus
, but Rapetosaurus has a long, low skull, with the nostrils on the top, similar to Diplodocus. This has allowed genera known only by Diplodocus-like skulls (like Quaesitosaurus
and Nemegtosaurus
and other nemegtosaurids) to be classified as macronarians rather than in Diplodocoidea
.
Analysis of the rest of the skull and the body has also confirmed what was only previous speculated: that titanosaurs are most closely related to the brachiosaurids. "The discovery of this dinosaur is particularly exciting because it confirms a close relationship between the titanosaurs and brachiosaurs, something that could only be surmised previously," according to Rich Lane, of the National Science Foundation
.
A complete skeleton can also serve as a baseline when reconstructing other titanosaurs from limited remains. This is the basis for new, revised estimates of the size of the super-giant titanosaurs.
, in St. Paul, Minnesota) and Catherine A. Forster, an Associate Professor at the Department of Anatomical Sciences of the State University of New York at Stony Brook
, in Stony Brook, New York
.
The Rapetosaurus is a member of the Nemegtosauridae family, which is within the unranked Titanosauria taxon.
in Malagasy folklore
) and sauros, which is Greek
for lizard
. The species epithet, krausei, is named after the team leader of the expedition, David W. Krause.
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 sauropod 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...
that lived in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
from 70 to 65 million years ago, at the end of the 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. Only one 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...
(R. krausei) has been identified.
Like other sauropods, Rapetosaurus was a quadrupedal herbivore
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...
; it is calculated to have reached lengths of 15 metres (49 ft).
Description
Tail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
, a very long neck
Neck
The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...
and a huge, elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...
-like body. Its head resembles the head of a 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...
, with a long, narrow snout and nostrils on the top of its skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
. It was a herbivore and its small, pencil-like teeth were good for ripping the leaves off trees but not for chewing.
It was fairly modest in size, for 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...
. The juvenile specimen measured 8 metres (26 ft) from head to tail, and "probably weighed about as much as an elephant", according to Kristina Curry Rogers. An adult would have been about twice as long (15 meters (49 ft) in length) which is still less than half the length of its gigantic kin, like Argentinosaurus
Argentinosaurus
Argentinosaurus is a genus of titanosaur sauropod dinosaur first discovered by Guillermo Heredia in Argentina. The generic name refers to the country in which it was discovered...
and 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...
.
Range
During the early part of the Late Cretaceous all groups of sauropods, with the exception of the titanosaurs, had gone extinct. The titanosaurs were the dominant herbivores of the Late Cretaceous on the southern continents. Their reign was cut short by the Cretaceous-Tertiary extinction eventCretaceous-Tertiary extinction event
The Cretaceous–Paleogene extinction event, formerly named and still commonly referred to as the Cretaceous-Tertiary extinction event, occurred approximately 65.5 million years ago at the end of the Maastrichtian age of the Cretaceous period. It was a large-scale mass extinction of animal and plant...
, which killed almost all the 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...
s about 65 million years ago.
Discovery and naming
The discovery of Rapetosaurus, known by the single species Rapetosaurus krausei marked the first time a titanosaurTitanosaur
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...
had been recovered with an almost perfectly intact skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
, complete with skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
. It has helped to clarify some difficult, century-old classification issues, among this large group of sauropod 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...
s and provides a good baseline for the reconstruction of other 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...
s that are known only from partial fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
ized remains.
The discovery was published in 2001 by Kristina Curry Rogers
Kristina Curry Rogers
Kristina A. Curry Rogers is a vertebrate paleontologist and currently Assistant Professor in geology and biology at Macalester College. She holds a B.Sc. in Biology from Montana State University, and a M.Sc. Ph.D. in Anatomical Science from the State University of New York at Stony Brook...
and Catherine A. Forster in the scientific journal Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
. The nearly-complete skeleton is that of a juvenile and partial remains from three other individuals were also recovered.
The Madagascar dig
The dig uncovered a partial skull (UA 8698, the 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...
specimen), another partial skull, a juvenile skeleton missing only a few tail vertebrae, and an unrelated vertebra. The juvenile skeleton, in particular, is the most complete titanosaur skeleton ever recovered and the only one with a head still attached to the body.
The fossilized remains were found in the Mahajanga basin in northwest Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, not far from the port city of Mahajanga
Mahajanga
Mahajanga is a city and a district on the north-west coast of Madagascar.- City :The City of Mahajanga is the capital of the Boeny region. Population: 135,660 ....
. They were recovered from a layer of sandstone known as the Anembalemba Member, which is part of the Maevarano Formation
Maevarano Formation
The Maevarano Formation is an Upper Cretaceous sedimentary rock formation found in the Mahajanga Province of northwestern Madagascar. It is most likely Maastrichtian in age, and records a seasonal, semiarid environment with rivers that had greatly varying discharges...
. The rock formation has been dated to the 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...
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, which means the fossilized bones are about 70 million years old.
They were found by a field team from the State University of New York at Stony Brook
State University of New York at Stony Brook
The State University of New York at Stony Brook, also known as Stony Brook University, is a public research university located in Stony Brook, New York, on the North Shore of Long Island, about east of Manhattan....
with the assistance of the local Universite d'Antananarivo. The team leader, David Krause, had been excavating fossils from the site since 1993.
A treasure-trove of bone
The Madadgascar location has produced a large number of significant paleontologicalPaleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
discoveries for Krause and his team. As well as dinosaurs, fossils of fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
es, frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s, turtle
Turtle
Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...
s, snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s, crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
s, bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, and mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s have been unearthed. Significant finds include:
- The skull of MajungasaurusMajungasaurusMajungasaurus is a genus of abelisaurid theropod dinosaur that lived in Madagascar from 70 to 65.5 million years ago, at the end of the Cretaceous Period. Only one species has been identified...
, a large carnivorousCarnivoreA 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...
theropod like TyrannosaurusTyrannosaurusTyrannosaurus 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...
, was discovered in 1996. It is similar to species found in IndiaIndiaIndia , 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...
and ArgentinaArgentinaArgentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, which indicate that land bridges between the fragments of the former supercontinent of Gondwana still existed in the late Cretaceous, far later than was previously believed. The most likely occurrence was a land bridge allowing animals to cross from South AmericaSouth AmericaSouth America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
to Antarctica, and then up to India and Madagascar. (See also Polar dinosaurs in AustraliaPolar dinosaurs in AustraliaThe South Polar dinosaurs proliferated during the Early Cretaceous while the continent of Australia was still linked to Antarctica to form East Gondwana, a continent that had rifted from Africa and drifted southward. Much of this southern continent lay inside the Antarctic Circle, and the climate...
.) - Majungasaurus fossils have also been discovered with teeth marks that clearly come from the same species, making it the first dinosaur known to have practiced cannibalism.
- MasiakasaurusMasiakasaurusMasiakasaurus was a small predatory theropod dinosaur from the Late Cretaceous of Madagascar. It was named in 2001 by Scott D. Sampson, Matthew Carrano, and Catherine A. Forster. Unlike most theropods, the front teeth of Masiakasaurus projected forward instead of straight down...
is a new species of theropod, with very unusual teeth that stick straight out from its jaw. - A single, 70 million year old marsupialMarsupialMarsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...
tooth. Madagascar was separated by water when the marsupials first evolved in the northern hemisphere, and there are no current species of marsupial on the island, which has revived the idea that colonies of animals might have somehow crossed vast stretches of water.
Implications
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
were represented by just a few bones, a partial skeleton or a skull. The first titanosaur
Titanosaurus
Titanosaurus is a genus of sauropod dinosaur, first described by Lydekker in 1877. It is known from the Maastrichtian Lameta Formation of India...
, discovered in 1887, is still only known from a partial skeleton.
This has made it difficult to determine not just the relationship between different genera of titanosaur but even how the titanosaurs are related to other, higher-level groups like the macronaria
Macronaria
Macronaria is a clade of sauropod dinosaurs from the Middle Jurassic to Late Cretaceous Periods of what are now North America, South America, Europe, Asia and Africa. The name means 'large nostrils' , in reference to the large nasal openings high on the head that probably supported fleshy...
ns (the group of "big nostril" sauropods, which include the titanosaurs, the nemegosaurids and the brachiosaurids). The whole taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
has been used as a dumping ground, with many genera labeled as incertae sedis (belonging to an unknown group), because not enough is known about them to classify them any further.
The Diplodocus-like skull has demonstrated that titanosaur skulls vary more than was previously believed. Most paleontologists believed that titanosaurs had box-like skulls with the nostrils midway up the snout, like the Camarasaurus
Camarasaurus
Camarasaurus meaning 'chambered lizard', referring to the hollow chambers in its vertebrae was a genus of quadrupedal, herbivorous dinosaurs. It was the most common of the giant sauropods to be found in North America...
, but Rapetosaurus has a long, low skull, with the nostrils on the top, similar to Diplodocus. This has allowed genera known only by Diplodocus-like skulls (like Quaesitosaurus
Quaesitosaurus
Quaesitosaurus is a genus of titanosaurian sauropod found by Kurzanov and Bannikov in 1983. The type species is Quaesitosaurus orientalis. It lived from 85 to 70 million years ago during the Late Cretaceous...
and Nemegtosaurus
Nemegtosaurus
Nemegtosaurus was a sauropod dinosaur from Late Cretaceous Period of what is now Mongolia. It was named after the Nemegt Basin in the Gobi Desert, where the remains — a single skull — were found...
and other nemegtosaurids) to be classified as macronarians rather than in Diplodocoidea
Diplodocoidea
Diplodocoidea was a superfamily of sauropod dinosaurs, which included some of the longest animals of all time, including slender giants like Supersaurus, Diplodocus, Apatosaurus, and Amphicoelias...
.
Analysis of the rest of the skull and the body has also confirmed what was only previous speculated: that titanosaurs are most closely related to the brachiosaurids. "The discovery of this dinosaur is particularly exciting because it confirms a close relationship between the titanosaurs and brachiosaurs, something that could only be surmised previously," according to Rich Lane, of the National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
.
A complete skeleton can also serve as a baseline when reconstructing other titanosaurs from limited remains. This is the basis for new, revised estimates of the size of the super-giant titanosaurs.
Classification
The new species, Rapetosaurus krausei, was described in the August 2, 2001 issue of the scientific journal Nature, by Kristina Curry Rogers (then a graduate student under Catherine Forster and now employed by Macalester CollegeMacalester College
Macalester College is a private, coeducational liberal arts college located in Saint Paul, Minnesota. It was founded in 1874 as a Presbyterian-affiliated but nonsectarian college. Its first class entered September 15, 1885. The college is located on a campus in a historic residential neighborhood...
, in St. Paul, Minnesota) and Catherine A. Forster, an Associate Professor at the Department of Anatomical Sciences of the State University of New York at Stony Brook
State University of New York at Stony Brook
The State University of New York at Stony Brook, also known as Stony Brook University, is a public research university located in Stony Brook, New York, on the North Shore of Long Island, about east of Manhattan....
, in Stony Brook, New York
Stony Brook, New York
Stony Brook is a hamlet located in the Town of Brookhaven in Suffolk County, New York, which is on the North Shore of Long Island...
.
The Rapetosaurus is a member of the Nemegtosauridae family, which is within the unranked Titanosauria taxon.
Etymology
The generic name Rapetosaurus is derived from Rapeto (a giantGiant (mythology)
The mythology and legends of many different cultures include monsters of human appearance but prodigious size and strength. "Giant" is the English word commonly used for such beings, derived from one of the most famed examples: the gigantes of Greek mythology.In various Indo-European mythologies,...
in Malagasy folklore
Folklore
Folklore consists of legends, music, oral history, proverbs, jokes, popular beliefs, fairy tales and customs that are the traditions of a culture, subculture, or group. It is also the set of practices through which those expressive genres are shared. The study of folklore is sometimes called...
) and sauros, which is 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...
for 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...
. The species epithet, krausei, is named after the team leader of the expedition, David W. Krause.
External links
- Paleontology News — Rapetosaurus from the Science Museum of Minnesota.
- Stony Brook Paleontologists Discover New Dinosaur and Name It in Honor of One of Their Own from SUNY-Stony Brook.
- New Dinosaur Species Found from Time for Kids Online.
- Skeleton of New Dinosaur "Titan" Found in Madagascar from National Geographic.
- Dino skull fills knowledge gap from the BBC.
- New Madagascar Dinosaur Discoveries from the T. Rex Museum.
- A press release, from the National Science Foundation, including a reconstruction (illustration).