zooblogogy: The World’s Cutest Extinct Species? The world’s smallest mammoth species, Mammuthus creticus, has recently been reported to have stood around 1 metre tall, around the size of a baby African elephant (Loxodonta africana). The fossils were found on the island of Crete in 1904, but only last year the discovery of a forelimb bone revealed the fossils to belong to the world’s smallest known mammoth species. The mimi mammoth is an example of the Island Rule, where large species get smaller and small species get larger on islands. Other examples of nanism or dwarfism include Homo floresiensis, a human species which stood less than 1 metre tall. In the other direction as examples of gigantism, a 12kg species of rabbit (Nuralagus rex) once inhabited Minorca, and the most famous case is the well known giant tortoise of the Galapagos islands. Reasons for these dramatic size changes are not fully understood, but it’s thought that the removal of predation risk on islands enables large species to evolve to be smaller, and the lack of larger competitors like mammalian browsers enables small species to become larger. Whatever the reason, move over micro pigs - I want a micro mammoth. Illustration by Victor Leshyk

zooblogogy:

The World’s Cutest Extinct Species?

The world’s smallest mammoth species, Mammuthus creticus, has recently been reported to have stood around 1 metre tall, around the size of a baby African elephant (Loxodonta africana). The fossils were found on the island of Crete in 1904, but only last year the discovery of a forelimb bone revealed the fossils to belong to the world’s smallest known mammoth species.

The mimi mammoth is an example of the Island Rule, where large species get smaller and small species get larger on islands. Other examples of nanism or dwarfism include Homo floresiensis, a human species which stood less than 1 metre tall. In the other direction as examples of gigantism, a 12kg species of rabbit (Nuralagus rex) once inhabited Minorca, and the most famous case is the well known giant tortoise of the Galapagos islands.

Reasons for these dramatic size changes are not fully understood, but it’s thought that the removal of predation risk on islands enables large species to evolve to be smaller, and the lack of larger competitors like mammalian browsers enables small species to become larger. Whatever the reason, move over micro pigs - I want a micro mammoth.

Illustration by Victor Leshyk

scinerds: Ankylosaur ReefArticle content from smithsonianmag.com (by Brian Switek).A full-size restoration of what Aletopelta might have looked like, at the San Diego Natural History Museum. Photo by Brian Switek. “Dinosaurs created temporary reefs. At least, the ones whose bodies floated out to sea did.” “Even though there were no aquatic dinosaurs, dead dinosaurs sometimes washed down rivers to the coast. When their bodies settled on the ocean bottom, scavengers of various sorts and sizes glommed onto the dinosaurs and formed short-lived communities with their own ecological tempo—perhaps similar to what happens to the carcasses of modern whales. The Cretaceous dinosaur bones found in my home state of New Jersey are the result of this kind of transport and marine breakdown, and other examples have been found at sites around the world.” “Even bodies of the heavily armored ankylosaurs were sometimes swept out to sea. They must have been quite a sight—a bloated, belly-up ankylosaur, drifting for as long as the gases inside its body could keep it afloat. One of these dinosaurs, found miles from the closest land at that time, was recently discovered in the oilsands of Alberta, Canada, but this wandering ankylosaur isn’t the only one we know of. When I visited the San Diego Natural History Museum last month, I saw another.” “Hung on the wall, the creature was less than half the dinosaur it used to be. Even though additional parts of the dinosaur were recovered when it was excavated during the construction of the Palomar-McClellan Airport in 1987, the articulated hindlimbs and adjoining hip material is what museum visitors are greeted with. (The rest sits in the collections.) At first glance, the specimen doesn’t look like much. But what makes this fossil so strange is the group of associated creatures. Embedded on and around the dinosaur bones were shells from marine bivalves and at least one shark’s tooth. This ankylosaur had settled and been buried in the sea off the coast of Cretaceous California.” “Tracy Ford and James Kirkland described the ankylosaur in a 2001 paper included in The Armored Dinosaurs. Previously, the specimen didn’t have a proper scientific name. The dinosaur was simply referred to as the Carlsbad ankylosaur. And the details of the dinosaur’s armor, especially over the hips, seemed to be quite similar to that of another dinosaur called Stegopelta. This would make the Carlsbad ankylosaur anodosaurid, a group of ankylosaurs that typically have large shoulder spikes but lack a tail club.” “After reexamining the specimen, though, Ford and Kirkland came to a different conclusion. The dinosaur’s armor identified it as an ankylosaurid, the armored dinosaur subgroup that carried hefty, bony tail clubs. The club itself was not discovered, but the rest of the dinosaur’s anatomy fit the ankylosaurid profile. And the dinosaur was different enough from others to warrant a new name. Ford and Kirkland called the ankylosaur Aletopelta coombsi. The genus name, meaning “wandering shield,” is a tribute to the fact that the movements of geologic plates had carried the dinosaur’s skeleton northward over the past 75 million years.” “We may never know exactly what happened to this Aletopelta. Detailed geological context is essential for figuring out how a skeleton came to rest in a particular spot, and that information was destroyed with the excavation of the skeleton. Still, paleontologists have put together a general outline of what happened to this dinosaur. The unfortunate ankylosaurid died somewhere along the coast, and its carcass was washed out to the sea by a river, local flood, or similar watery mode of transport. Aletopelta settled belly-up and was exposed for long enough to become a food source and even home for various organisms. Sharks and other larger scavengers tore at the carcass, but various encrusting invertebrates also settled on the skeleton. Fortunately for paleontologists, the skeleton was sturdy enough to survive all this and eventually be buried. Even though dinosaurs never lived in the marine realm, their deaths certainly enriched the sea.” References: Ford, T., Kirkland, J. 2001. Carlsbad ankylosaur (Ornithischia: Ankylosauria): An ankylosaurid and not a nodosaurid. pp. 239-260 in Carpenter, K., ed. The Armored Dinosaurs. Bloomington: Indiana University Press.Hilton, R.P. 2003. Dinosaurs and Other Mesozoic Reptiles of California. Berkeley: University of California Press. pp.39-40

scinerds:

Ankylosaur Reef
Article content from smithsonianmag.com (by Brian Switek).
A full-size restoration of what Aletopelta might have looked like, at the San Diego Natural History Museum. Photo by Brian Switek.

“Dinosaurs created temporary reefs. At least, the ones whose bodies floated out to sea did.”

“Even though there were no aquatic dinosaurs, dead dinosaurs sometimes washed down rivers to the coast. When their bodies settled on the ocean bottom, scavengers of various sorts and sizes glommed onto the dinosaurs and formed short-lived communities with their own ecological tempo—perhaps similar to what happens to the carcasses of modern whales. The Cretaceous dinosaur bones found in my home state of New Jersey are the result of this kind of transport and marine breakdown, and other examples have been found at sites around the world.”

“Even bodies of the heavily armored ankylosaurs were sometimes swept out to sea. They must have been quite a sight—a bloated, belly-up ankylosaur, drifting for as long as the gases inside its body could keep it afloat. One of these dinosaurs, found miles from the closest land at that time, was recently discovered in the oilsands of Alberta, Canada, but this wandering ankylosaur isn’t the only one we know of. When I visited the San Diego Natural History Museum last month, I saw another.”

“Hung on the wall, the creature was less than half the dinosaur it used to be. Even though additional parts of the dinosaur were recovered when it was excavated during the construction of the Palomar-McClellan Airport in 1987, the articulated hindlimbs and adjoining hip material is what museum visitors are greeted with. (The rest sits in the collections.) At first glance, the specimen doesn’t look like much. But what makes this fossil so strange is the group of associated creatures. Embedded on and around the dinosaur bones were shells from marine bivalves and at least one shark’s tooth. This ankylosaur had settled and been buried in the sea off the coast of Cretaceous California.”

“Tracy Ford and James Kirkland described the ankylosaur in a 2001 paper included in The Armored Dinosaurs. Previously, the specimen didn’t have a proper scientific name. The dinosaur was simply referred to as the Carlsbad ankylosaur. And the details of the dinosaur’s armor, especially over the hips, seemed to be quite similar to that of another dinosaur called Stegopelta. This would make the Carlsbad ankylosaur anodosaurid, a group of ankylosaurs that typically have large shoulder spikes but lack a tail club.”

“After reexamining the specimen, though, Ford and Kirkland came to a different conclusion. The dinosaur’s armor identified it as an ankylosaurid, the armored dinosaur subgroup that carried hefty, bony tail clubs. The club itself was not discovered, but the rest of the dinosaur’s anatomy fit the ankylosaurid profile. And the dinosaur was different enough from others to warrant a new name. Ford and Kirkland called the ankylosaur Aletopelta coombsi. The genus name, meaning “wandering shield,” is a tribute to the fact that the movements of geologic plates had carried the dinosaur’s skeleton northward over the past 75 million years.”

“We may never know exactly what happened to this Aletopelta. Detailed geological context is essential for figuring out how a skeleton came to rest in a particular spot, and that information was destroyed with the excavation of the skeleton. Still, paleontologists have put together a general outline of what happened to this dinosaur. The unfortunate ankylosaurid died somewhere along the coast, and its carcass was washed out to the sea by a river, local flood, or similar watery mode of transport. Aletopelta settled belly-up and was exposed for long enough to become a food source and even home for various organisms. Sharks and other larger scavengers tore at the carcass, but various encrusting invertebrates also settled on the skeleton. Fortunately for paleontologists, the skeleton was sturdy enough to survive all this and eventually be buried. Even though dinosaurs never lived in the marine realm, their deaths certainly enriched the sea.”

References: Ford, T., Kirkland, J. 2001. Carlsbad ankylosaur (Ornithischia: Ankylosauria): An ankylosaurid and not a nodosaurid. pp. 239-260 in Carpenter, K., ed. The Armored Dinosaurs. Bloomington: Indiana University Press.
Hilton, R.P. 2003. Dinosaurs and Other Mesozoic Reptiles of California. Berkeley: University of California Press. pp.39-40


paleoillustration:

Araripesuchus wegeneri andKaprosuchus by Todd Marshall

paleoillustration: Tetrapod fauna of the upper Triassic Chinle Formation of Petrified Forest National Park, Northern Arizona.

paleoillustration:

Tetrapod fauna of the upper Triassic Chinle Formation of Petrified Forest National Park, Northern Arizona.


paleoillustration:

Helicoprion and Stethacanthus by Julio Lacerda


dino-files:

Name: Deinonychus
Pronounced: Die-Non-E-Cuss
Classification: Theropod
Sub-family: Dromaeosaurid
Temporal Range: Early Cretaceous (115-108 Mya)
Length: 3.2 metres
Height: 1.1 metres
Weight: 70kg
Movement: Bipedal
Feeding Type: Carnivore

Information:
- Discovery: The first remains of Deinonychus were discovered in 1931 by famous palaeontologist, Barnum Brown. The fossil was discovered in Montana, USA; but at the time Brown was more concerned with excavating the remains of the ornithopod, Tenontosaurus. During his report of the dig, Brown noted that along with the remains of Tenontosaurus his team had recovered the remains of a small carnivorous dinosaur. He made preparations for the remains of this dinosaur to be described and put on display, but he never finished his work. It wasn’t until 1964 when researcher John Ostrom discovered a large number other fossils, that were the same as the one discovered by Barnum Brown; that Deinonychus was officially described and named. In addition a large number of fossilised egg shells were discovered around the original Deinonychus specimen; and they have since been proven to be those of Deinonychus and thus the first identified dromaeosaurid dinosaur egg.
            Deinonychus is a member of the dromaeosaurid group of dinosaurs. It is closely related to the smaller, Velociraptor although it lived long before its more famous relative, nearly 25 million years in fact.

- Statistics: Deinonychus was a fairly large dromaeosaurid dinosaur, growing to lengths of around 3 metres; much larger than its close relatives; Velociraptor (1.9m), Tsaagan (2m) and Saurornitholestes (1.8m). Recent estimates have suggested it would have weighed around 70kg. The skull of Deinonychus measured around 41cm in length and had powerful jaws which were lined with around seventy curved, blade-like teeth.

- Description: Deinonychus is one of the most important dinosaurs in regards to the argument that some dinosaurs were warm blooded. Dinosaurs have always been compared to modern-day reptiles (which are cold-blooded); however smaller dinosaurs such as Deinonychus were built to be fast and agile. Such a lifestyle requires the need for a faster metabolism, which is provided via being warm-blooded. In addition, the egg shells discovered around the original specimen of Deinonychus were arranged in such a way, it suggested that Deinonychus would have brooded (sat on) its eggs. This would suggest that Deinonychus used body heat transfer as a mechanism for egg incubation; which would require a warm-blooded lifestyle, similar to modern-day birds. While there is no direct evidence to support the placement of feathers on Deinonychus, it is presumed, that like its dromaeosaurid relatives, it would have supported a feather coat.
            Many palaeontologists believe that Deinonychus was a pack animal. Evidence for this comes from the frequent remains of Deinonychus being found around Tenontosaurus fossils. Tenontosaurus was a large ornithopod dinosaur and a single Deinonychus would have found it extremely difficult to take down an adult Tenontosaurus; suggesting packs of Deinonychus would have hunted larger prey animals. It is belived that Deinonychus used the large sickle-claw on its foot for stabbing prey, rather than slashing open flesh in a single stroke (which was previously suggested). The claw itself varies in length and curvature in nearly all individuals; however no real reasoning for this has been proposed. It has been suggested that the difference in size and shape of the sickle-claws could be due to individual, sexual or age-related variations. There is recent anatomical and footprint evidence proving that this claw was held off the ground while Deinonychus walked on its third and forth toes.
            In addition the tail of Deinonychus was constructed in a similar way to other members of its family group with each tendon overlapping several vertebrae, making the tail rigid and only allowing movement at the base. It is theorised that this stiff tail would have acted as a counterbalance when running and turning at speed. Deinonychus itself is often regarded as a fairly speedy animal, however recent research has suggested that the small foot-tibia ratio proposes that Deinonychus was not particularly fast in comparison to other dinosaurs. The research concluded that the legs of Deinonychus represented a balance between running adaptations needed for an agile predator and stress-reducing features to compensate for its unique sickle-claw. 


paleoillustration:

“Citipati with chicks”, ”Citipati and Shuvuuia” and sketches, by Edyta.

fuckyeahdinoart: Bambiraptor feinbergorum by *kyoht

fuckyeahdinoart:

Bambiraptor feinbergorum by *kyoht

discoverynews: Shaggy T. Rex Cousin Was Heftiest Feathered Dino    A 3,086-pound shaggy tyrannosaur was the world’s largest known feathered animal — living or extinct — according to a paper in the latest issue of Nature. The newly unearthed tyrannosaur, named Yutyrannus huali or “beautiful feathered tyrant,” lived about 125 million years ago in northeastern China. The over 29-foot-long non-avian dinosaur, represented by three specimens, is considerably smaller than its infamous relative T. rex, but some 40 times the weight of the largest previously known feathered dinosaur, Beipiaosaurus. keep reading

discoverynews:

Shaggy T. Rex Cousin Was Heftiest Feathered Dino   

A 3,086-pound shaggy tyrannosaur was the world’s largest known feathered animal — living or extinct — according to a paper in the latest issue of Nature.

The newly unearthed tyrannosaur, named Yutyrannus huali or “beautiful feathered tyrant,” lived about 125 million years ago in northeastern China. The over 29-foot-long non-avian dinosaur, represented by three specimens, is considerably smaller than its infamous relative T. rex, but some 40 times the weight of the largest previously known feathered dinosaur, Beipiaosaurus.

keep reading

paleoillustration: Titanoboa cerrejonensis painting by James Gurney “With a subject he could neither see nor photograph, Gurney constructed a small maquette scene from oven-hardened clay, rocks, and sticks in a Chinese food takeout container. Challenged by the the snake’s extraordinary length, he decided to show the titanoboa rising half out of the water in a death match with a crocodilian, a giant forebear of the modern crocodile. “The main purpose of my piece is to try to imagine what would otherwise just be a fairly ordinary fossil—to go from that to imagining a very dramatic moment in the life of this creature and to take us in a time machine to see what it really might have looked like,” says Gurney”. Full article.

paleoillustration:

Titanoboa cerrejonensis painting by James Gurney

“With a subject he could neither see nor photograph, Gurney constructed a small maquette scene from oven-hardened clay, rocks, and sticks in a Chinese food takeout container. Challenged by the the snake’s extraordinary length, he decided to show the titanoboa rising half out of the water in a death match with a crocodilian, a giant forebear of the modern crocodile. “The main purpose of my piece is to try to imagine what would otherwise just be a fairly ordinary fossil—to go from that to imagining a very dramatic moment in the life of this creature and to take us in a time machine to see what it really might have looked like,” says Gurney”.

Full article.

fuckyeahdinoart: australovenator by ~atrox1 Palaeoart done right

fuckyeahdinoart:

australovenator by ~atrox1

Palaeoart done right

nationalpost: Canadian scientists identify two new species of dinosaurs that could help fill in evolutionary gapsA team of five Canadian scientists has identified two new species of dinosaurs from the famous fossil beds of southern Alberta, including one that points to the pivotal North American evolution of a family of pint-sized, plant-eating creatures related to the triceratops. (Illustration: Julius Csotonyi)

nationalpost:

Canadian scientists identify two new species of dinosaurs that could help fill in evolutionary gaps
A team of five Canadian scientists has identified two new species of dinosaurs from the famous fossil beds of southern Alberta, including one that points to the pivotal North American evolution of a family of pint-sized, plant-eating creatures related to the triceratops. (Illustration: Julius Csotonyi)


dailyfossil:

Psittacosaurus

Mounted skeletons from the Melbourne Museum of Natural History

Reconstruction on display at the Carnegie Museum of Natural History

When: Early Cretaceous (~130 to 100 million years ago)

Where: Asia

What: Psittacosaurus is a ceratopsian.  Yes, a ceratopsian like Tricerotops or Styracosaurus, even though it has no horns or even a neck frill. You have to start somewhere! Psittacosaurus is an extremely basal ceratopsian, with some studies finding this animal in the first group to branch off from the clade. Italso was most likely bipedal (quick remake all the reconstructions!), as its forelimbs were much shorter than its hind-limbs, and it possibly could not even rotate its hands enough to put its palms flat towards the ground. This isn’t really surprising, as despite the large number of quadrupedal dinosaurs, the last common ancestor of all dinosaurs has been reconstructed to be bipedal. Psittacosaurus was a plant eater, but it did not have the grinding cheek teeth of later ceratopsians, so it swallowed stones to help it grind its food. It is also possible that it fed on nuts, as its beak has been reconstructed to function very well as a nut-cracker. 

There are hundreds upon hundreds of fossil specimens known for Psittacosaurus, making it one of the most well understood of all dinosaurs. There are over 10 species known, with the best known  Psittacosaurus mongoliensis, reaching about 6.5 feet (~2 meters) long at its extreme maximum. This includes an amazing slab specimen that was preserved in soft mud that shows this little ceratopsian had bristles on the top of its tail. It is thought these were used for communication between individuals, and it is debated if these are homologous (same evolutionary origin)to the feathers of theropod dinosaurs or not. There is almost a full ontogenetic (growth) series of specimens, with oodles and oodles of hatchings to subadults. The close association of many hatchlings and adults shows that these ceratopsians, like many dinosaurs, had a good amount of parental care of the young dinosaurs.

One benefit of so many specimens is that destructive sampling can be used - this is where the original specimen is damaged, or even destroyed, to provide some information about the animal. Cutting long bones and examining the resulting cross-sections has lead to the determination that Psittacosaurus lived to about 10 to 11 years old. 

Remember Repenomamus from a couple of days ago? The juvenile dinosaur  found inside was a Psittacosaurus.  

Psittacosaurus is such a weird little dinosaur…

theropod: Mick Ellison’s Microraptor reconstruction, based on new evidence that it sported iridescent black plumage.   Gorgeous. I love the way that our perception and knowledge of dinosaurs is evolving.

theropod:

Mick Ellison’s Microraptor reconstruction, based on new evidence that it sported iridescent black plumage.  

Gorgeous. I love the way that our perception and knowledge of dinosaurs is evolving.

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