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Sabertooth diaries 1: excavating old sketches by Mauricio Antón

“As the publication of my book  ”Sabertooth” comes closer, I am trying to put some order in the mass of material I have been working with during the last few years. It is interesting to leaf through those fat folders full of sketches, some of them dating from MANY years ago: it refreshes my memory about some of the main subjects I have dealt with in the book, and in fact, it motivates me to tackle some of these subjects again, in anticipation for the next book (title to be disclosed at some point in the future…).

Here are some of those “paleo-sketches” (in the whole sense of the word!). They date from more than 15 years ago (Gosh!) and were  my early attempts to put together observations about key aspects of big cat anatomy, especially related to hunting…(these drawings do not appear in the book or anywhere else  in this form, so this is a sort of exclusive…)

In the years after I did these sketches I have found many fascinating things about these aspects of felid anatomy, which I have tried to reflect in the new book. These days I am preparing a short video about some of these things, I expect to be posting it soon!”

  • First image: “compares the “primitive” skeletal porportions of the early cat Pseudaelurus (left) with those of the very different cheetah (Acinonyx) and sabertooth (Smilodon). Obviously, the skeletons and cats are not shown to scale”
  • Second image: “shows aspects of the anatomy of the cheetah, with special attention to the lumbar vertebrae.  For the fun of it, I also included a body size comparison betwen the modern cheetah and the extinct species Acinonyx pardinensis.  Back then I was already puzzled by the possible meaning of the changes in body proportions during the evolution of sabertooths, and in particular in the shortening of the lumbar vertebra in many species”
  • Third image: “shows the sequence of events during a hypothetical hunt by the sabertooth Smilodon: the chase (top); the wrestling struggle (middle); and the killing bite (bottom)”
  • Fourth image: “shows the crucial point when the cat attempts to pull a large prey down to the ground, and it highlights some of the muscles relevant for that action”

(Image and text source: Chasing Sabretooths; via @Laelaps on Twitter)

crownedrose.tumblr.com üzerinde izle

Today is so exciting for a ton of fellow palaeontologists, students, researchers, and myself… Dreadnoughtus has finally been published!

The video above gives you guys a bit of history to where this titanosaur was discovered back in 2005. Almost ten years later and it’s finally gone public! With a name like Dreadnoughtus, it’s hard not to want to run around saying its awesome name.

These fossils spent a lot of time being excavated out of the matrix they were found in; around 4 years with multiple labs working tirelessly to clean and repair them. We had to get it done at least in some sort of quick time, right? With such a huge specimen, a lot of man power is required!

I’m so proud and happy for everyone involved that we can now share this gorgeous dinosaur to the public! It’s MASSIVE. The fossils are just mind blowing to look at, and now we continue to move forward with its preservation, education, and further research. It’ll be going back to Argentina next year.

You can read the article about Dreadnoughtus here on Drexel University’s website, and the scientific paper on Nature.com (which some super awesome people I know worked on).

Stunningly Intact Dinosaur Fossil

The almost perfectly complete fossil of a young theropod dinosaur – including some preserved hair and skin* (see update below) – was unveiled yesterday by scientists from the Bavarian paleontological and geological collections (BSPG) in Munich, Germany. BSPG conservator Oliver Rauhut described it as the best preserved dinosaur skeleton to have ever been found in Europe.

Darren Naish, palaeontologist at the University of Southampton, says the fossil is “incredible”. Rauhut says that fossils of theropod dinosaurs, which include the genus Tyrannosaurus, are rare and usually fragmented. “The best-preserved Tyrannosaurus we have are about 80 percent preserved, and that is already terrific,” he says. The new fossil is around 98% intact.

The dinosaur died around 135 million years ago at a site near the present town of Kelheim in the southern German state of Bavaria. Rauhut and his team of palaeontologists think it was no more than a year old

Naish hopes that the bone preservation in the fossil is as outstanding as it looks in the publically-released photo, because this might help scientists piece together the phylogeny of theropod species. No data is available on the fossil yet, so Naish can only speculate, but he says the dinosaur seems to have proportionally shorter legs, and a longer tail, than have been seen in other similar theropods. Particularly tantalising is the question of whether these differences are attributable to the dinosaur being a juvenile, or if it might be an example of a new species.

Read more.

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Glass Fossils Inspire Molten Dreams
  • by Glendon Mellow

“When Mary Anning discovered the first fossil ichthyosaur skeleton along the Blue Lias cliffs of Dorset, could she have dreamed something like this? Amanda Heath is an art teacher and sculptor working in the mixed media of copper, glass and wood, and inspired by the Jurassic coast of Dorset.  Here are a few more pictures of the process of making the Glass Ichthyosaur. Her process is as wonderful to see as the final form. I might also note that when your artistic medium of choice is molten glass poured over shiny metal, you can use as much lens flare in your photography as you want. True story. And because I can’t help myself when it comes to trilobites, here’s a copper and glass one peeking its cephalon up from the grass. Thanks to Amanda Heath for sharing her work with us here on Symbiartic!”

(Source: Scientific American)

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older vs modern reconstructions

Helicoprion (“Spiral Saw”) was a long-lived genus of shark-like cartilaginous fish that first arose in the oceans of the late Carboniferous 280 million years ago, survived the Permian-Triassic Extinction Event, and eventually went extinct during the early Triassic, 225 million years ago.

image

The only fossils known are the teeth, which were arranged in a fantastic “tooth-whorl” strongly reminiscent of a circular saw. It was not until the discovery of the skull of a relative, Ornithoprion, that it was realized that the tooth-whorl was in the lower jaw. The tooth-whorl represented all of the teeth produced by that individual in the lower jaw, in that as the individual grew, with the older, smaller teeth being moved into the center of the whorl by the appearance of larger, newer teeth. Comparisons with other eugenodontids suggest that Helicoprion may have grown up to 10-15 ft (3-4 m) long.

The exact location of the tooth-whorl in the lower jaw is an open debate. Older reconstructions placed the whorl in the front of the lower jaw; however this would create drag, making the shark a less efficient swimmer, and turbulence, alerting prey of its approach. A more current and scientifically accepted reconstruction places the whorl deeper into the throat. This arrangement would be best suited for soft bodied prey.

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Coloured modern reconstruction illustration [2] by Mary Parrish

Other images currently unsourced

New evidence suggests Archaeopteryx dressed in black.

Scientists have found a way to uncover feathered dinosaurs’ true colors, and one of the first creatures to come under inspection is none other than Archaeopteryx — an iconic but mysterious theropod believed by many to be the “missing link” between dinosaurs and birds.

Now, by examining a single, exceptionally well-preserved feather, one group of paleontologists believes it has the evidence it needs to weigh in on the color of Archaeopteryx's prehistoric plumage. This bird, say the researchers, wore black.

image

By comparing the patterns of melanosomes contained within the Archaeopteryx feather (seen above) with the those found in the plumage of 87 similar, modern bird species, the researchers were able to determine that the feather was almost certainly black. What’s more, the researchers say Archaeopteryx's melanosomes would have provided its wings a structural advantage, as well.

"If Archaeopteryx was flapping or gliding, the presence of melanosomes would have given the feathers additional structural support,” said Ryan Carney, an evolutionary biologist at Brown and the paper’s lead author. “This would have been advantageous during this early evolutionary stage of dinosaur flight.”

Read the full article at io9.

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Look, a big meat-eater! Is that a Tyrannosaurus rex?
A simple guide to telling the difference in large carnivorous theropod dinosaurs.
by: crownedrose.

I’ve been in situations where I’ve witnessed, or have had someone ask me the question to whether that big theropod over there is a T. rex. Seeing as the Tyrannosaurus is one of the most well known dinosaurs on Earth, many people mistake other large meat-eating dinosaurs as the T. rex as well. The photos above showcase nine different large sized theropod dinosaurs, including Tyrannosaurus rex in the middle photo.

What is a theropod, you ask? To put it simply, theropoda is the suborder for the bipedal saurischian dinosaurs, which consists of the world’s favourite, T. rex, and is also the suborder which helps us link to the evolution of birds. Many people can’t tell straight away if the big skeleton they see on display is a T. rex or not until they look at the identification panel. If it looks to have a similar skull or a large skeletal body like T. rex, some people will pin it as such. This post is meant to help you see the differences in these guys for the next time you’re at the museum. Each photo above is the skull profile of a large theropod, and the descriptions will also include quick identification traits for the rest of the skeleton. How many can you identify?

1. Albertosaurus sarcophagus (photo source): Albertosaurus is commonly mistaken for a Tyrannosaurus because they are both in the same family: Tyrannosauridae. Albertosaurus was smaller than Tyrannosaurus, but shares the similar features of a large skull, heterodont teeth, and two digits on short forelimbs. On the top of the skull (above and slightly in front the eyes) are bony crests. As well, Albertosaurus is more slender than Tyrannosaurus, especially when you look at the lower legs. (full skeleton)

2. Allosaurus fragilis (photo source): Allosaurus may be one of the more common theropods mistaken for a T. rex that I’ve witnessed. Though smaller than the T. rex, the shape of an Allosaurus skull is flatter at the top, and also is decorated with horns above the eyes, along with a pair of ridges that went along the top of the nasal bones, meeting to the horns. Allosaurus as well had three digits on its forelimbs instead of two like Tyrannosaurus rex. (full skeleton)

3. Carcharodontosaurus saharicus (photo source): In Jurassic Park III, we witness a fight between T. rex and Spinosaurus. Though, do you want to know who who the true rival is? You guessed it: Carcharodontosaurus! (Both reining from what is now Northern Africa). Carcharodontosaurus is larger than T. rex, with three digits on it’s forelimbs (of decent length), a longer skull, and long serrated teeth. (full skeleton)

4. Carnotaurus sastrei (photo source): I’ve done a lot of research work on Carnotaurus the past few months, and when it comes to pathetic forelimbs, Carnotaurus definitely wins out compared to T. rex! Meaning “meat-eating bull”, Carnotaurus has two thick horns decorating its skull right above the eyes; definitely an appropriate name. The skull itself is bulky (and short in length) looking, until you look at the lower jaw that tends to be slender. It’s a very distinctive skull, but those two bull-like horns on the top of the skull and very short arms (don’t let Terra Nova’s bad rendition of the “Carno” fool you!) will help you quickly identify it. (full skeleton)

5. Tyrannosaurus rex (photo source): In centre is the skull of my favourite T. rex: Sue! Most people can recognise them by their iconic skeletons and thick/massive teeth and jaws, but you’d be surprised as well. With such a massive head and body, these dinosaurs were machines when it came to ripping apart carcasses. Then there’s those small forelimbs with two finger digits which are not as pathetic as the public thinks; they’re actually quite powerful! In the Tyrannosauridae family, T. rex is the largest. Most people know a Tyrannosaurus when they see one, but the skull is featured in the centre to show the differences in all nine animals listed here. They have long hind legs (especially compared to the skeleton proportion as a whole), and their skull is quite wide near the back, whereas the tip of the front part of the skull is more narrow; overall, the skull of T. rex is very robust. This structure helped T. rex to have great binocular vision (unlike how T. rex is depicted in Jurassic Park to have movement-based vision was just a fabrication). Like other theropods (and sharks), T. rex constantly replaced their teeth, which were also heterodont (meaning their teeth took on different shapes depending where they lay inside the jaws). (full skeleton)

6. Spinosaurus aegyptiacus (photo source): Believe it or not, I’ve seen people mistake Spinosaurus as a T. rex multiple times. I’ve been surrounded by dinosaurs my entire life, so I’m not sure how you can confuse two very different (and distinct) specimens. Spinosaurus has a large sail on its back, which are extensions of the vertebrae, and a long crocidillian-like snout. If you’ve ever watched Jurassic Park III, you’ll remember this guy being the main antagonist. (full skeleton)

7. Daspletosaurus torosus (photo source): Daspletosaurus is another good example of being mistaken for a T. rex. Daspletosaurus - just like Albertosaurus - is actually in the same family as Tyrannosaurus rex: Tyrannosauridae. Just like T. rex, Daspletosaurus is equipped with two finger digits ending with claws, short forelimbs (though not as short compared to T. rex), but was smaller compared to its North American cousin. Daspletosaurus also walked what is today western North America, but lived about 10 million years before Tyrannosaurus rex came onto the scene. The skull itself had crests near the eyes, and the ‘holes’ in the skull (aka orbit/eye socket, for example) were a bit different in shape compared to T. rex. Sometimes for closely related dinosaurs such as Daspletosaurus and T. rex, you must look closer and closer at detail, and one good way is by look at the shapes of those “holes”. Random note: this guy is the blurry dinosaur in my layout background. (full skeleton)

8. Giganotosaurus carolinii (photo source): This dinosaur is usually confused with Carcharodontosaurus as they are closely related, both belonging to the family Carcharodontosauridae. Giganotosaurus has a long skull (some have described it to me as almost “stretched”), is estimated to be the largest skull of any known theropod, and its teeth are different than Tyrannosaurus: shorter and more narrow. Many though do confuse this to be a T. rex, which is why it’s on the list! (full skeleton)

9. Ceratosaurus nasicornis (photo source): Ceratosaurus is one of my favourite theropods. Decorated with horns/crests above the eyes and a blade-like nasal horn (which is where its name comes from: “horned lizard), these dinosaurs lived in the Late Jurassic. The horns help easily identify these dinosaurs, along with its distinctively long and serrated teeth. Ceratosaurus was much smaller than the T. rex, had shorter forelimbs for its body (possessing three digits on each hand), and one of the more flexible theropods on this list. (full skeleton)

As I was entering the dinosaur names in google and flickr to get photos, I can’t tell you how many of these nine specimens came up in the search when I was not looking for them at that time! There are more theropods out there who get mistaken as a Tyrannosaurus, but the eight above are the ones I see this happen to the most. In the end, you can’t just look at the skull or just the rest of the body to clearly identify a dinosaur; you must take everything into account. Luckily, museums have those nice identification plates for the public to read, but hey, next time you may not need to read them!

If you’d like to know more detailed information about the theropods mentioned here, I am currently writing a series of posts (for Tumblr) called “Theropod Of The Day”. Daily posts (depending on my schedule) will give you quick and easy information on the dinosaurs listed above, and others that are not mentioned here! I’m hoping to get the series started next week, so keep a lookout for the posts, and track the tag “theropod of the day" on Tumblr!

Carnotaurus sastrei (by Ryno720)

Meaning “Meat-Eating Bull”, Carnotaurus is a large theropod which is found in Argentina, South America. T. rex usually gets picked on when it comes to its “wimpy” forelimbs, but try being a Carnotaurus for a day! Their forelimbs were much weaker, with their radius and ulna being only one fourth the size of its humerus, along with two out of four digits bearing finger bones.

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Herbivorous Dinosaurs from Alberta. By Julius Csotonyi

"About 75 million years ago, shows niche partitioning at work. It is likely that dietary differences between each species allowed the habitat to support such a diverse population of herbivores." Read more at Species New to Science

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