Dimetrodon

Source: http://phenomena.nationalgeographic.com/2014/02/07/sail-backed-dimetrodon-had-a-nasty-bite/

Name: Dimetrodon (species: D. angelensis, D. booneorum, D. dollovianus, D. giganhomogenes, D. grandis, D. limbatus, D. loomisi, D. macrospondylus, D. milleri, D. natalis, D. occidentalis, D. teutonis

Name Meaning: Two Measures of Teeth 

First Described: 1878

Described By: Cope 

Classification: Eukaryota, Unikonta, Opisthokonta, Holozoa, Filozoa, Metazoa, Eumetazoa, Bilateria, Deuterostomia, Chordata, Olfactores, Craniata, Vertebrata, Gnathostomata, Eugnathostomata, Teleostomi, Osteichthyes, Sarcopterygii,  Rhipidistia, Tetrapodomorpha, Tetrapoda, Reptiliomorpha, Amniota, Synapsida, Pelycosauria, Eupelycosauria, Sphenacodontia, Sphenacodontoidea, Sphenacodontidae, Sphenacodontinae

Dimetrodon was a synapsid from the Sakmarian age of the Early Permian, about 295 to 272 million years ago. It is well known for the large sail on its back, formed by elongated spines from the vertebrae. It was quadrupedal and had a long curved tail and heterodontition in its jaw. Fossils of it have been found in both the USA and in Northern Europe, with the first fossils found by Cope in the Red Beds of Texas. It has also been found in Utah, Texas, Oklahoma, and even Ohio and Illinois (I should go looking for it), as well as Germany. Being a synapsid, it was characterized by having only one temporal fenestra, or hole behind the eye socket. This makes it not a reptile, as reptiles are characterized by having two temporal fenestrae. However, it was an amniote, meaning it probably laid eggs, though egg fossils from the species have not been found. 

Source: http://paleoillustration.tumblr.com/post/10169392160/el-gran-depredaror-big-predator-by-marco

The animal was up to 4 meters long and a carnivore, with finely serrated teeth and was probably the top predator of its environment. It had two different types of teeth: grabbing teeth, and shearing flesh teeth, allowing it to make short work of its prey. The sail was highly vascularized, though the webbing may not have extended all the way to the tips of the spins. This sail may have been used as camouflage, allowed for more stable side to side movement, or have been thermoregulatory. The evidence for thermoregulation is conflicting at best: the sail grew much faster than was necessary for thermoregulation, and it actually could have evolved for sexual selection, and thus could have been used as a display structure. Dimetrodon may have been sexually dimorphic as well, as there are two slightly different body size classes. It is still mildly unsure though which one is which sex. 

Source: http://de.jurassic.wikia.com/wiki/Dimetrodon

This animal lived in a complex, but early land based ecological community, living in vast wetlands and lowland ecosystems of the Permian. It lived alongside amphibians Archeria, Diplocaulus, Eryops, and Trimerorhachis, the reptiliomorph Seymouria, the reptile Captorhinus, and the other synapsids Ophiacodon and Edaphosaurus. There are some juvenile specimens known, though they are a different species from known adult Dimetrodon and juveniles and adults may or may not have lived alongside one another. It is known from many species, but D. grandis was the largest known one. Other species show different morphology in the shape of the sail as well as the size of the sail. 

Sources: 

http://en.wikipedia.org/wiki/Dimetrodon

http://www.prehistoric-wildlife.com/species/d/dimetrodon.html

Shout out goes to perilousechidna!

There are people who believe that humans dinosaurs co-existed, that they roamed the Earth at the same time. There are museums that children go to, in which they build dioramas to show them this. And what this is, purely and simply, is a clinical psychotic reaction. They are crazy. They are stone-cold-fuck nuts. I can’t be kind about this, because these people are watching The Flinstones as if it were a documentary.
—  Lewis Black, Red, White, and Screwed

Taking a bite out of Wednesday!
This has been a long week and I’m ready to be done! L-R: Borealosuchis sternbergii, Brachychampsa montana and Cimolestes stirtoni. All on display at @nhmla’s Dino Hall. #paleontology

A fossil skeleton of a primitive, Eocene aged whale at “Whales Valley”, 150 km southwest of Cairo, Egypt.  This spectacular site helps to provide an explanation to one of the biggest mysteries of the evolution of whales, the emergence of the whale as an ocean going mammal from a land-based animal. No other place in the world yields the number, concentration and quality of such fossils making it at particularly scientifically important location.

The whales found in Whale Valley possess small hind limbs, a feature that is not seen in modern whales.  They also have a powerful skull with teeth like those found in carnivorous land mammals. Several other types of mammals are present including three species of sea cows. These were fully marine like the whales, and likewise show primitive features not seen in modern species and possess teeth that suggest that they grazed on seagrasses and other marine plants.

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NEW SPECIES ALERT!

Oxford scientists have discovered the fossil remains of a six foot long lobster-like sea monster. It’s called Aegirocassis benmoulae (named after the Moroccan fossil hunter Mohamed Ben Moula who discovered the remains). It’s part of a group of species called “anomalcaridids” - giant plated arthropod ancestors who ruled the Cambrian and Ordovician seas (520 - 443 million years ago). FULL STORY HERE

Most of anomalcaridids were like sharks, hunting other sea creatures, but this new species is more like a baleen whale. It used spines on its head to filter sea water and trap tiny particles of food.

Images:

  • A reconstruction of the Aegirocassis benmoulae by Marianne Collins/ArtofFact.
  • The Aegirocassis's spiny net filter that it used for feeding.
  • Allison Daley, one of the scientists who described this new species, at a dig.
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A beautifully articulated, rear paddle of a 183 million year old Ichthyosaur. The paddle is approximately 8 inches long. It comes from the Posidonia Shale Formation formation in Southern Germany.

Ichthyosaurs (“Fish Lizard”) was a giant marine reptile which thrived from much of the Mesozoic era. They evolved in the mid Triassic from a group of unidentified land reptiles which transition back into the water. This line evolved in parallel to the ancestors of todays dolphins and whales, something known as convergent evolution.

A new premium fossil list at Fossil Era.

Archaeopteryx 

A bird that lived during the Late Jurassic period that is a transitional species between feathered dinosaurs such as Velociraptor and Anchiornus, and modern birds. The feather impressions found on archaeopteryx are advanced flight feathers, and suggest feathers began evolving well before the Late Jurassic. Also, this fossilized version is super creepy and super cool.

[Image: A flock of Hatzegopteryx. One paces along on all fours, another rockets into flight by pushing off with its strong forelimbs, and the rest soar above them.]

Pterosaur Myths Busted (V3)

Pterosaurs are a staple of movies featuring prehistoric animals—yet most media depictions of the poor beasts remain woefully stuck in the 19th century. Real pterosaurs were just about nothing like the sluggish, flimsy-winged gliders that populated our childhood picture books and movies. Here we take a look at how some common misconceptions about them stack up against the facts. 

Misconception: “Pterodactyl” and “pterosaur” mean the same thing.

Fact: “Pterosaur” applies to the entire group, but “pterodactyl” is only correct when you’re referring to, well, pterodactyloids.

In general, pterodactyls had proportionally shorter tails, longer necks, bigger heads, and longer hand bones than non-pterodactyls. Compare these skeletal drawings of Rhamphorhynchus (a non-pterodactyl) and Pteranodon (the ’dactyl of Jurassic Park fame).

M: Pterosaurs were dinosaurs.

F: Dinosaurs fall under the orders Ornithischia and Saurischia. Pterosaurs do not belong to either group, though current evidence places them as close relatives of the dinosaurs within Ornithodira

M: Pterosaurs were the ancestors of birds.

F: Like their cousins Velociraptor and T. rex, birds are a type of theropod dinosaur. Pterosaurs left no living descendants.

M: Pterosaurs had scaly / leathery / bald skin.

F: Though the pads of their feet were scaly, most of a pterosaur’s body was covered in hairlike filaments called pycnofibers. Pterosaurs of the primitive family Anurognathidae, such as the one shown below, seem to have been fluffed up from snout to tail with pycnofibers.

M: Pterosaurs were “cold-blooded.”

F: Nope. With no body heat to insulate there wouldn’t be much point to pycnofibers.

M: Pterosaurs could pick things up with their feet.

F: Their feet were much better suited to walking than grasping. Like humans, they had plantigrade feet—in other words, the entire sole of the foot contacted the ground as they walked.

M: Grounded pterosaurs walked on their hind legs / could only crawl around on their bellies.

F: Pterosaurs usually walked on all fours, and many were quite adept at ground locomotion to boot, especially the pterodactyls. Some, such as the dsungaripteroids, may even have been capable of galloping. The three in the illustration below are shown badgering an azhdarchid for its kill.

M: All pterosaurs had teeth / were toothless.

F: Pterosaurs had all kinds of dental arrangements, from completely toothless to jaws positively bristling with the things—just look at Pterodaustro below. (Pteranodon was toothless, by the way; its name even means “toothless wing.”)

 

M: Females of crested species had large head crests like the males.

F: Head crests were probably sexually dimorphic, with males usually having much larger, more elaborate head decoration, as demonstrated by these two Darwinopterus

M: Pterosaur wing membranes were leathery, flimsy and prone to tearing.

F: Pterosaur wings were supple, complex, multilayered structures. They were reinforced with closely-packed fibers called aktinofibrils. 

M: Each wing was supported by several fingers like a bat’s.

F: Only the hugely elongated fourth finger supported the wing; the other three fingers were much smaller. See here for a diagram of the pterosaur wing. 

M: Pterosaurs had sharply-pointed wing tips.

F: Such a wing shape would have made flight difficult. Here’s our anurognathid friend again, showing off its nice rounded wing tips for you.

 

M: Some pterosaurs were too big / heavy to fly.

F: Even the largest pterosaurs were probably capable of powered flight. 

M: Pterosaurs could only take off by falling from a cliff / tree / [insert high starting point here].

F: They could launch into flight under their own power using all four limbs, a strategy also known in some modern bats. This is called “quadrupedal launch” (or just “quad launch”). See this video for a pterosaur quad launch demonstration.

M: All pterosaurs were ocean-going fish hunters.

F: They occupied a variety of niches, and many lived inland.

M: Pterosaurs cared for their hatchlings in much the same way as modern birds.

F: Other than protecting them during the hatching process, pterosaur parents might not have had much to do with their offspring (called “flaplings”) since they could probably fly almost immediately after birth.

Recent findings reveal that at least some pterosaurs, such as Hamipterus, were social and may have built their nests together in huge colonies.

M: Pterosaurs went extinct because they were outcompeted by birds.

F: The evidence for this idea is weak at best.

M: Live pterosaur sightings prove that pterosaurs never really went extinct. 

F: This idea relies on scant evidence as well. 

—————

If you have anything more than a passing interest in pterosaurs, you really should pick up a copy of paleontologist Mark Witton’s book on themPterosaur.net is another useful resource of information about these fascinating, ridiculous creatures.

Sources to avoid include David Peters’ Pterosaur Heresies and ReptileEvolution.com. While these sites seem professional on the surface and feature loads of attractive artwork, scientists have been unable to replicate the results of Peters’ research, and repeatable results are a hallmark of good science. Read more about Peters here (PDF), here and here

(Credit: Skeletal drawings by Scott Hartman; all other illustrations by Mark Witton.) ( #long post )

Another NHMLA specimen: Entelodont archaeotherium. 

Entelodonts, sometimes facetiously termed hell pigs or terminator pigs are an extinct family of pig-like omnivores endemic to forests and plains of North America, Europe, and Asia from the late Eocene to early Miocene epochs.

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The first of its kind- Baby Woolly Rhino Discovered In Siberia

Sasha, the baby wooly rhino, in all her glory; (inset) the specimen was discovered at the Abyysky District of Siberia’s Sakha Republic. Pictures: Academy of Sciences.

The pristine specimen of the tiny extinct rhino—the only one of its type ever found—was discovered in permafrost along the bank of a stream in Siberia’s Sakha Republic, The Siberian Times reported.

"At first we thought it was a reindeer’s carcass, but after it thawed and fell down we saw a horn on its upper jaw and realized it must be a rhino," Alexander ‘Sasha’ Banderov, the hunter who made the discovery, told the Times. "The part of the carcass that stuck out of the ice was eaten by wild animals, but the rest of it was inside the permafrost and preserved well." Experts hope to be able to extract DNA from remains of the extinct creature which was today being handed over to scientists from the  Academy of Sciences in Yakutsk, capital of the Sakha Republic, also known as Yakutia.

Replica of a woolly rhino created by Remie Bakker, 2010

The age of the cub when it died has yet to be established, but scientists estimate it to be about 18 months old. Precise tests will be conducted to ascertain when Sasha died, with the results likely in six months. The creature’s wool is well preserved, and an ear, one eye, its nostrils, and mouth are clearly visible.

Albert Protopopov, Head of the Mammoth Fauna Department of Sakha Republic Academy of Sciences, said: “The find is absolutely unique. We can count a number of adult woolly rhinos found around the world on fingers of one hand. A baby rhino was never found before. We know nothing about baby rhinos, while the morphology of adults is better known. So far we didn’t have a chance to work even with a tooth of a baby rhino, and now we have the whole skull, the head, soft tissues, and well preserved teeth.”

Sources:

Fossilization is an extremely rare event.

To appreciate this point, consider that there are 10 specimens of the first bird to appear in the fossil record, Archaeopteryx.

All were found in the same site in Germany where limestone is quarried for printmaking (the bird species name is lithographica). If you accept an estimate that crow-sized birds native to wetland habitats in northern Europe would have a population of around 10,000 and a life span of 10 years, and if you accept the current estimate that the species existed for about two million years, then you can calculate that about two billion Archaeopteryx lived.

But as far as researchers currently know, only 1 out of every 200,000,000 individuals fossilized. For this species, the odds of becoming a fossil were almost 40 times worse than your odds are of winning the grand prize in a provincial lottery.

—  Biological Science, Second Canadian Edition (Textbook); Freeman, Harrington, Sharp
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Metoposaurus Algarvensis

A new subspecies of the extinct amphibian Metoposaurids has been found in Portugal, the first ones to be found on the Iberian peninsula. This prehistoric salamander was much different than the salamanders of today. They were roughly 7-feet long, with jaws full of razor-sharp teeth. These predators were far more like crocodiles, terrorizing the rivers of the Triassic period.

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Winner of the 2014 Vertebrate Find Of The Year over at the Fossil Forum. An upper jaw of Pelagornis, a giant (think 15-20 foot wingspan), false-toothed bird.  From the Calvert Formation of Maryland, early Miocene in age.  Found and prepared by forum member BusyEagle.

Pelagornis  probably was closely related to todays pelicans and storks.  The earliest birds in the fossil record had teeth.  These “false teeth” are one of the transitional features between non-avian dinosaurs and the birds of today.   You can read more about this early pseudo toothed bird over at National Geographic.

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And your absolutely insane trilobite for the day is the Koneprusia with preserved secondary spines. Not only is it a rare species of Koneprusia but it requires tremendous amount of skill and time to preserve the secondary spines during preparation. In most specimens they simply get abraded away, It easily doubles the preparation time to preserve them and this specimen took over 100 hours of work under microscope to prepare. 

Just added for sale at Fossil Era.

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