The Story of Allosaurus Allosaurus is one of the most iconic fossils
from the Jurassic Period. As a large carnivorous therapod, Allosaurus
has been featured in numerous documentaries about dinosaurs, and has come to represent
the classic Jurassic predatory dinosaur in our imaginations. With an estimated length of around 6 meters
long, Allosaurus was smaller than its much younger cousin Tyrannosaur rex, but considerably
larger than Velociraptor. It was one of the climax predators of the
Jurassic Period in North America and Europe. My name is Benjamin Burger and in this video,
I’ll telling the story of Allosaurus. The story of the first discovery of Allosaurus
in the American West is tied up with the race to find dinosaur bones by two eccentric paleontologists
O.C. Marsh and Edward Drinker Cope. But preceding their race, a paleontologist
by the name of Joseph Leidy, would described what many regarded as the first fossil specimen
in 1870. There is a bit of mystery and confusion about
where this first specimen was found. The fossil was collected during an expedition
to Colorado by the geologist Ferdinand Hayden in 1869. Hayden traveled along the front range of Colorado,
describing the geological formations and collecting fossils. In his very extensive notes he does not detail
the discovery of the fossil, which was supposedly found in Middle Park, in the northern part
of Colorado, maybe near Hot Sulfur Springs. The problem is that region of Colorado lacks
Jurassic Age rocks, and when the specimen was sent to Joseph Leidy to describe he attributed
it to the Cretaceous. Hayden was a brilliant geologist and familiar
with the sequence of Jurassic and Cretaceous rocks in Colorado. If the first specimen is from the Cretaceous
it may not represent an Allosaurus at all. If it came from the Late Cretaceous Middle
Park Formation it would be a contemporary with Tyrannosaurus. Leidy initially referred the specimen collected
by Hayden on January 11th 1870 to Poekilopleuron valens, and placed the specimen in the Smithsonian
Museum as Catalogue Number 218. Poekilopleuron is a genus of dinosaur discovered
in France, in Normandy and described in 1836 and 1837. Leidy had access to the monograph and plates
illustrating the specimen from France, and noticed similarities. Poekilopleuron is a middle sized theropod
from the Jurassic Period of Europe, but does not get much attention today, since the holotype
was destroyed during World War II. Enough casts of the original specimen exist
today to compare it, but few other specimens have come to light since 1944. Leidy noted that the vertebra from Colorado
was much larger, but similar to this theropod dinosaur from Europe. Based on this isolated caudal tail vertebrae
in Colorado Leidy named it a new genus in 1873, which he called Antrodemus. However, given its locality and looking at
the partial caudal vertebra in the museum, it equally is likely that Antrodemus is actually
another type of large theropod. In fact, it has a higher probability of belonging
to Tyrannosaurus rex, and if discovered in a latest Cretaceous Formation it would make
more sense that it belongs to a Tyrannosaurid. But the name Antrodemus was entered into the
scientific literature and would be used to refer to many of the large theropod dinosaurs
found in the American West, principally by workers after 1873, but not by the eccentric
paleontologists Cope and Marsh. During the 1870s Cope and Marsh would inflict
the world of paleontology with numerous, and I mean numerous names of dinosaurs. Each bone they excavated, no matter how fragmentary,
would be given a new name, resulting in a huge proliferation of scientific names for
dinosaurs. Both were at war with each other to see who
could name the most fossils, and the discoveries of dinosaurs in the American West fueled this
battle. In 1877, Denver newspapers reported the discovery
of large dinosaur bones near Canon City Colorado in Garden Park, these bones were set to be
shipped to Edward Cope in Philadelphia for description. Discovered by Henry Felch the bones where
impressive, and he hoped that he could earn some money with further excavations. Marsh sent one of his collectors, a man named
Benjamin Mudge to attempt to find where these dinosaur bones were being found and see if
he could excavate some for Marsh. Mudge would discover another nearby site in
August of 1877, then hired Henry Felch and his brother to help with the excavations,
capturing the supply of bones from Cope. The quarry was named the Felch Quarry, and
was excavated for only several months from September to October of 1877, with the bones
sent back to Marsh to describe. Marsh was eager to name the dinosaurs from
these bones. He named Allosaurus fragilis from the scrappy
material sent to him at the end of 1877, to prevent Cope naming dinosaurs he had obtained
from the same year. Allosaurus fragilis is based on a tooth, two
dorsal vertebra, and the proximal phalanx or toe bone, catalogue number YPM 1930. Not much to establish a new dinosaur name
on, but enough to lay claim to dinosaurs in Colorado, before Cope could described his
fossils. Edward Drinker Cope followed by named his
fossils from the Jurassic Morrison Formation in Garden Park Colorado, Epanterias amplexus,
catalogue number AMNH 5767, which consists of three vertebrae, a coracoid and metatarsal. It is not very complete, and Cope did not
even know what type of dinosaur these bones belong to, but today most scientists attribute
it to Allosaurus, the same dinosaur Marsh described a few months earlier. Both Allosaurus fragilis and Epanterias amplexus
were found from Garden Park Colorado and scientists have debated over whether the names should
be considered valid. Because Marsh beat out Cope in naming Allosaurus
fragilis, it has stood as the valid name today, but both are based on really scrappy remains. Marsh begin collecting fossils from Como Bluff
Wyoming, from the Jurassic Morrison Formation, and named a new species in 1878 Allosaurus
lucaris from some vertebra, pectoral elements and limb bones, under catalogue number YPM
1931. While Cope named Hypsirophis discursis based
a neural spine, under catalogue number AMNH 5731 from Garden Park Colorado. Not to be out done, Marsh returned with his
newest dinosaur in late 1878 named Creosaurus atrox, which was the most complete specimen
to date, included the right premaxilla; jugal; sacral vertebrae; lumbar vertebrae; caudal
vertebrae; phalanges; ilium and astragalus. Found at Como Bluff Wyoming, the fossil was
collected by Samuel Williston who had also worked at Garden Park Colorado the year before
for Marsh. It is catalogued as YPM 1890. Marsh followed in 1879, with a new dinosaur
Labrosaurus sulcatus based on a tooth from Garden Park Colorado. So in a short span of time from 1877 to 1879,
seven names were proposed, which all have been referred to as likely specimens of Allosaurus
from the Jurassic Morrison Formation, or of dubious affiliation with Allosaurus. Marsh rolled out a new name for a similar
dinosaur in the 1880s, describing a new species of Labrosaurus, he called Labrosaurus ferox
based on a lower jaw, that lacks teeth from Garden Park Colorado Smithsonian specimen
USNM 2315. Despite all these names scientists really
did not have a good idea what this dinosaur looked like, and what name they should use,
and so instead of using any of Cope and Marsh’s names they often would refer to this dinosaur
as Antrodemus. So by the turn of the century, the list of
names was long and complex mess. After Cope and Marsh had died, Charles Gilmore
was the first worker to detangle the mess, and what he did was establish Leidy’s name
Antrodemus as the characteristic Jurassic meat-eating dinosaur of the Morrison Formation
in the 1920s. He did this by erected a topotype in USNM
4734, a beautiful preserved skeleton from Garden Park Colorado, that was identified
as Allosaurus fragilis by Marsh, but referred to Antrodemus valens using Leidy’s nomenclature. USNM 4734 bares special mention because it
was the specimen that first gave scientists a good picture of what this dinosaur looked
like. The specimen was collected in 1879, from Garden
Park Colorado, and features a partial skull and right lower jaw, a complete set of presacral
and sacral vertebrae, a few ribs, a pelvis, and virtually complete arms and legs. There is some debate whether USNM 2315 the
type specimen of Labrosaurus ferox, also belongs to this specimen, since it is left lower jaw,
missing from this specimen. The specimen was placed on display at the
Smithsonian Museum in Washington DC, but was not the first Allosaurus specimen to be given
a display That belongs to a box, crated up and sent
to Edward Drinker Cope from excavations at Como Bluff Wyoming. This box had been left unopened during Cope’s
life, as he raced to name dinosaurs. Before his death, Cope will his collection
of fossils to the American Museum of Natural History in New York City, where the unopened
box was sent after he died. This would have been the best unboxing video,
if they had YouTube back then, because when they opened the box inside was a beautifully
preserved skeleton. In 1903, the specimen was put on display. It was the first large theropod dinosaur to
be mounted in a museum, and drew large crowds. The skull was largely sculpted based on Marsh’s
early specimen of USNM 4734, but enough of the skeleton was preserved to give a good
picture of the animal. I love this display, because it has not changed
since 1903, whereas the Smithsonian museum display of USNM 4734 has undergone multiple
revisions since its discovery. It currently is reconstructed as if it is
on a nest of eggs, resting on the ground. The first rather complete specimen of Allosaurus
from Utah was discovered in 1924 at Dinosaur National Monument in the Carnegie Quarry which
is located in the northeastern part of the state. DINO 2560 is on display at the Quarry Building
north of Jensen Utah, and is a beautiful nearly complete skull. So you likely are asking yourself when did
we start calling, Allosaurus, Allosaurus, rather than Antrodemus valens. This did not happen until the 1970s, with
the work of one guy, James Madsen. In the 1930s the University of Utah discovered
dinosaur bones in the Jurassic Morrison Formation on the north side of the San Rafael Swell,
this dinosaur quarry would become one of the richest accumulations of Allosaurus bones
every discovered, including over 46 individuals. Its known as the Cleveland-Lloyd Dinosaur
Quarry. It’s a strange assemblage of carnivorous
meat-eating dinosaurs, most identified as Allosaurus. The bones were highly scattered about, and
disarticulated. James Madsen worked as the paleontologist
at the site to help oversee the dig from 1960 until the late 1980s, and reconstructed the
skeleton. In 1976, James Madsen published his famous
monograph on Allosaurus, re-erecting the name Allosaurus, rather than Antrodemus, and providing
some of the most amazing images of a creature that lived 150 million years ago. James Madsen argued that Antrodemus was based
on too fragmentary of material, and advocated for USNM 4734 to be the neotype for the species
Allosaurus fragilis. Museum displays were updated to begin calling
this dinosaur Allosaurus, and new displays were made to illustrate every bone of this
creature! The massive bone bed of the Cleveland-Lloyd
Dinosaur Quarry revolutionized our image of predatory dinosaurs in the late 1970s, spurring
what became known as the dinosaur renaissance of the 1980s and 1990s. Over 65 museums exhibit Allosaurus skeletons
that come from this quarry, including most of the specimens on display in Salt Lake City
at the Utah Natural History Museum and at the Prehistoric Museum in Price. In 1979, another amazing Allosaurus specimen
was discovered, it is one of my favorite specimens of Allosaurus, and part of that is because
of who discovered it. It was found by a 12-year-old girl named India
Wood. India Wood is a legend in paleontology, and
when she was a girl she was dumped off at a remote ranch in Northwestern Colorado during
the summer by her divorced parents, discovered a dinosaur on the ranch in Jurassic rock layers. She later brought the dinosaur bones to the
attention of the Denver Museum, which returned with her to finish excavating the site, led
by a drunken paleontologist and his son. The specimen is now on display at the Denver
Museum, and her story is amazing one. She is currently writing a very personal memoir
about the dinosaur discovery, which I hope is made into a movie, you should check out
her synopsis and first chapter, on her website. I’ve linked below, because I hope to hear
more of this story of its discovery from one of my personal heroes in paleontology. India Wood’s dinosaur discovery, and the
work of James Madsen ushered in a new period of dinosaur craze that would lead to many
new excavations of Allosaurus. During this time, all specimens were attributed
to Allosaurus fragilis, a single species that ranged across North America. In the 1990s two dinosaurs were discovered
that would make headlines years after their initial discovery, and represent a second
species of Allosaurus. The official naming of which would take thirty
years, a very different length of time, then the speedy naming of dinosaurs by Cope and
Marsh in the 1870s. The first specimen was associated with a famous
dinosaur quarry called the Howe Quarry that was excavated by the American Museum in the
1930s, near Shell Wyoming, in the northern part of Wyoming near the Bighorn Mountains. The excavations were led by Barnum Brown,
the man who discovered Tyrannosaurus rex, and included a team of paleontologists with
great hats. Except for this guy, poor guy. The Howe Quarry is an amazing dinosaur quarry,
which was located on a ranch originally owned by Barker Howe. The site was filled with bones of the iconic
large sauropod dinosaurs, but few allosaur remains were found. In 1991 some Swiss privately funded dinosaur
hunters purchased the rights to reopen the private quarry, but where not having much
luck, they then started searching the surrounding land for dinosaurs, and came upon a beautiful
preserved Allosaurus. They brought in heavy equipment and built
a road to the site, unfortunately they had ventured onto Public Land owned by the federal
government of the United States. The BLM was called in after it was reported
that people had illegal constructed a road on public land, and the Feds discovered a
tarp covering a complete dinosaur, an Allosaurus named Big Al. Big Al was turned over to two local museums
to help excavate, and no criminal charges were filed to the Swiss paleontologists. The dinosaur became catalogue in the Montana
Museum of the Rockies (MOR 693), the skeleton was 95% complete, and somewhat articulated,
with a beautiful complete skull. A cast of the dinosaur is on display at the
University of Wyoming Geology Museum in Laramie, as well as the Museum of the Rockies in Montana. Big Al got its own documentary in the year
2000, as a two part follow up to the successful British television documentary series Walking
with Dinosaurs. It is an incredible specimen, known for its
many injuries! The Swiss paleontologists kept working in
the area, and found a second Allosaurus named Big Al 2 for their museum back in Europe. The area around the Howe Quarry near Shell
Wyoming has been reinvestigated by a number of museums and private dig sites, most of
which are pulling out sauropod dinosaurs like Camarasaurus, but several additional specimens
of Allosaurus have been found. The next Allosaurus specimen that bears mentioning
was found in 1990 in Dinosaur National Monument, with excavations going from 1990 to 1997. The skeleton was beautifully articulated,
but missing a skull. It was found in a hard sandstone that was
tilted by the uplift of the mountains over millions of years. The specimen was lifted out by helicopter,
and preparation was carried out at the quarry building inside the Dinosaur National Monument
by Ann Elder and Scott Madsen, and seen by thousands of visitors to the national monument
in Utah. Including a much younger me, when I visited
the quarry in the summer of 1996 back when I was in college. The skull, was eventually found using gamma
ray detection, a method to detect radioactive elements, and was found to be nearly a meter
away locked in the hard sandstone. After the skeleton was prepared casts were
made and put on display, with the intention of naming it a new species of Allosaurus,
named after James Madsen. This specimen is known as DINO 11541, and
is the holotype for the species Allosaurus madseni described in 2020. Now before I dive into what made people think
that this specimen was a new species, I want to talk about two other specimens of Allosaurus. The first is Allosaurus specimen was one that
was found, 5,000 miles away, in Portugal, in 1999, not far from Lisbon. At first it was thought to belong to Allosaurus
fragilis, but was given a new species name, Allosaurus europaeus. What is interesting is that parts of the skull
were found of this dinosaur compare very closely with Allosaurus fragilis from North America. During the Jurassic Period, Europe and North
America where much closer together, with the Atlantic Ocean slowly opening up in a rift
valley between the two continents. Allosaurus appears to have a huge geographic
range, which is similar to large predators today, such as many bears and wolves, and
in the recent past lions in the Northern Hemisphere. The second specimen is one found in Colorado
near the same site that India Wood found the specimen in the Denver Museum. This one was found by Dana Forbes a local
resident and school teacher in 2000, who owned a ranch with exposures of the Jurassic Morrison
Formation north of town, adjacent to Dinosaur National Monument. Forbes belongs to a religious sect that believes
that the Earth is very young, and he partnered with a man named Joe Taylor who runs a tiny
museum and ministry in Texas near Lubbock. The two excavated the specimen of Allosaurus
from 2000 to 2002, but in 2002 they partnered with a man named Pete DeRosa who ran a business
in Florida called Creation Expeditions, that runs a series of religious schools in Florida,
and wanted to make the dinosaur dig a summer activity for his school children back east
to visit. Between 2002 and 2004, the dig was open to
religious school groups from the east coast to visit, Pete DeRosa offered to buy the dinosaur
from Forbes and Taylor for over a hundred thousand dollars, and one of the participates
of the dig was a wealthy congressman and his daughter from North Carolina by the name of
Mark Meadows, who purchased the entire ranch from Dana Forbes in 2004. Dana then used the money to start a local
charter school in town, which closed in 2007. Pete DeRosa in the purchase arrangement had
a discloser that the dinosaur and any information about it could not be released to the public,
or the contract would be void. Pete DeRosa argued that Joe Taylor had talked
about the dinosaur and even featured it in a video at his museum, thus nullifying the
agreement. Joe Taylor never got the money, and Pete DeRosa
now had a dinosaur that he could use to promote his schools. DeRosa and Meadows hope to make the ranch
a summer destination for religious groups, but the business was losing money. In 2013, their religious school was got up
in a pedophilia scandal, the dinosaur and the ranch had become a liability and both
were sold to a church called Answers in Genesis ministered by an Australian named Ken Ham,
who is well known on YouTube for his religious and anti-science views and was building an
Ark in Kentucky. Answers in Genesis purchased the ranch and
currently has no plans to further excavations on the site. In any case, the Allosaurus is on display
in Kentucky, and features a nice skull that is characteristic of Allosaurus fragilis,
but has not been described formally in any publications. I bring this specimen up because there are
four nice skulls of Allosaurus from around Dinosaur National Monument, and only one is
referred to as a sperate species, Allosaurus madseni. The other specimens referred to Allosaurus
madseni is the Big Al specimen from Northern Wyoming (MOR 693) and Big Al 2, SMA 0005 from
near the Howe Quarry, so there is no geographic isolation between the two species, they appear
to live in the similar geographic area, although not enough is known about the correlative
stratigraphy to say if they existed at the same time in history. Now I want to talk about what physically distinguishes
Allosaurus fragilis from Allosaurus madseni, and it has to do principally with the jugal
bone. In Allosaurus madseni the jugal bone does
not curve downward, or ventrally from the skull, whereas in Allosaurus fragilis it has
this distinct curve. Now DINO 11541 the holotype is smaller than
Allosaurus fragilis, but that might be because it is a juvenile. Now one of the questions I have about this
trait is whether it might be ontogenetic, might it be that DINO 11541 from Dinosaur
National Monument and the Big Al specimen MOR 693 are just juvenile specimens, and that
as the animal grows the jugal curves. The large collection of jugal bones from the
Cleveland-Lloyd quarry all show various aged individuals with a wide range of jugals, and
they all appear to show this curvature, indicating they belong to Allosaurus fragilis. However, ones from Dinosaur National Monument
appear to be variable. Two specimens likely collected by Jim Jensen
for BYU show a non-curved jugal as well, and are interpreted as belonging Allosaurus madseni,
as does the two specimens from Northern Wyoming, however not figured are the three other specimens
from near Dinosaur National Monument that do show curvature. There may be a more northern form Allosaurus
madseni, and a more southern form Allosaurus fragilis in this trait, with Dinosaur National
Monument at the border of the ranges of these two species, with an slight overlap. A follow up paper has shown that the interpretation
of the anterior portion of the jugal is likely incorrect, with the jugal being part of the
back or posterior part of the antorbital fenestra, this is important because in large specimens
the jugal bone near its contact with the maxilla can be invaginated with a pneumatic cavity
extending from this fenestra in the skull, and the curvature might be influenced by this
cavity in some individuals. The fact that the anterior part of the jugal
is part of the antorbital fenestra suggests that Allosaurus europaeus is likely the same
as Allosaurus fragilis. But does not negate the trait in Allosaurus
madseni. The other character that distinguishes Allosaurus
madseni from Allosaurus fragilis is the crests on the top of the skull, all Allosaurus specimens
have crests on the lacrimal bones, but Allosaurus madseni appears to have crests, or more pronounced
crests on the nasal bones as well. I’ve always been fascinated with this rugose
or rough crests on the lacrimal bones of Allosaurus, which give the skull a unique look. The nasal bone crests add a little more flare. Crests in birds are often formed by the invagination
of sinuses, either from the avian respiratory system or from the brain cavity, like in the
domestic breeds of chickens Polish Crested and Silkie Chickens which expand the skull
by a herniating of the central nervous system. Not so in Allosaurus, which composes these
crests from thickening of the bone. An example of a living bird that has thickening
of the bone to serve as crests is the crested guineafowl’s skull in Africa. In life these birds exhibit crazy hair pieces,
of downy and curly feathers that is used to distinguish different species. I often wonder if these crests in Allosaurus
served as support for feathers on the top of the head, that could distinguish different
species, and Allosaurus madseni may have had a more pronounced tuff of feathers atop its
head. This gave me an idea to reconstruct the new
species of Allosaurus, Allosaurus madseni using the crests as support for feathers,
like those seen in crested guineafowl. The only reconstructions I’ve seen of Allosaurus
madseni is the beautiful almost snake like reconstruction by artist Andrey Atuchin, and
I thought I would do a very different reconstruction using feathers. To do this I first drew the skull and draw
over the skull with the flesh, skin, scales and feathers using pencil. It is an equal possible look that Allosaurus
may have sported, based on its close relationship to birds. -
So with this video, I’m giving away this original art and I will choose from random
a card from a deck, with the names of those supporters who contribute to a new $5 level
or above that now appears on my Patreon page, if you like a chance at some original artwork
of dinosaurs and other extinct creatures, click on the link in the distribution below,
if you currently support me on the $1 level maybe consider increasing it to $5. [And the winner is…..] I also want to send a thank you to many of
my long time supports on Patreon including Fred Olney, Brian Clever, Chris Green, Paolo
Luzzatto-Fegiz, Magnus Solvang, Shawn Cromett, Emmett Larson, and Niso. Thanks guys!
Allosaurus is one of the most iconic dinosaurs from the Jurassic Period, but did you know that for most of its history it was known by a different name? Antrodemus... This is the story of Allosaurus and the most famous fossilized skeletons of this dinosaur that have been discovered over 140 years, since the first one was pulled out of the ground.
I really enjoyed this