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Big Prehistoric Mammalian Herbivores ~
Big Prehistoric Mammalian Herbivores ~
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Big Prehistoric Mammalian Herbivores ~
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http://blogs.scientificamerican.com/lael...B_EVO_BLOG
The Battle for the Bone Wars Beasts Multihorned, saber-toothed herbivores set the stage for one of paleontology's greatest conflicts  *This image is copyright of its original author  *This image is copyright of its original author
http://m.phys.org/news/2016-06-historic-...cient.html
The first fossil skull of Castoroides ohioensis found in 1845 alongside the skull of a modern beaver. Credit: New York State Museum A few snippets of protein extracted from the fossil of an extinct species of giant beaver are opening a new door in paleoproteomics, the study of ancient proteins. Ancient proteins can be used to place animals on the evolutionary tree, and could offer insights into how life and Earth's environment have evolved over time. Typically, paleoproteomics relies on fossils collected for the purpose. But in a paper published today in the Proceedings of the Royal Society B, researchers at Rensselaer Polytechnic Institute (RPI) used a fossil collected more than 170 years ago in central New York, and housed at the New York State Museum.  *This image is copyright of its original author
I thought this would be interesting to add.
The Evolution of Maximum Body Size of Terrestrial Mammals - Abstract "The extinction of dinosaurs at the Cretaceous/Paleogene (K/Pg) boundary was the seminal event that opened the door for the subsequent diversification of terrestrial mammals. Our compilation of maximum body size at the ordinal level by sub-epoch shows a near-exponential increase after the K/Pg. On each continent, the maximum size of mammals leveled off after 40 million years ago and thereafter remained approximately constant. There was remarkable congruence in the rate, trajectory, and upper limit across continents, orders, and trophic guilds, despite differences in geological and climatic history, turnover of lineages, and ecological variation. Our analysis suggests that although the primary driver for the evolution of giant mammals was diversification to fill ecological niches, environmental temperature and land area may have ultimately constrained the maximum size achieved."   *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author Diprotodon, meaning "two forward teeth", it is the largest known marsupial to have ever lived, it existed from approximately 1.6 million years ago until extinction some 46,000 years ago (through most of the Pleistocene epoch). Diprotodon fossils have been found in sites across mainland Australia, including complete skulls and skeletons as well as hair and foot impressions. The largest specimens were hippopotamus-sized: about 3 metres (9.8 ft) from nose to tail, standing 2 metres (6.6 ft) tall at the shoulder and weighing about 2,790 kilograms (6,150 lb). Aboriginal rock art images in Quinkan traditional country (Queensland, Australia) have been claimed to depict diprotodonts. They inhabited open forest, woodlands, and grasslands, possibly staying close to water, and eating leaves, shrubs, and some grasses. The closest surviving relatives of Diprotodon are the wombats and the koala. It is suggested that diprotodonts may have been an inspiration for the legends of the bunyip, as some Aboriginal tribes identify Diprotodon bones as those of "bunyips".
Antique water horses
Posted on September 6, 2014 by twilightbeasts The year 2014: An enormous 64 foot long hippopotamus makes its way slowly down the River Thames. Longer than a double decker bus, it’s big soft eyes softly peer out of the water welcoming onlookers as it slowly glides past. Created by the Dutch artist, Florentijn Hofman, this giant wooden art instillation was made as part of the Totally Thames festival, and someone has been rather witty and christened it ‘HippopoThames’. But this oversized, flat bottomed piece of art is not in isolation. Part of the festival includes a talk by Madame Trowel Blazer herself, Victoria Herridge, about the prehistoric Thames and the real hippopotamuses that lived there around 125,000 years ago. Along with giant Straight Tusked elephants (Palaeoloxodon antiquus), an extinct type of rhinoceros (Stephanorhinus sp.), and cave lions (Panthera spelaea), hippopotamus were very at home in Britain 125,000 years ago. These were the modern hippos which are still around today, Hippopotamus amphibius. From Trafalgar Square, all the way up north to Derbyshire, during this rather warm interglacial period, Britain’s lakes and rivers were teeming with these giant mammals. There was another species of hippo that once lived in Britain, and Europe. An extinct hippo, that was the largest river horse ever to have existed. Fossils of the European Hippopotamus (Hippopotamus antiquus) first appear in sediments 1.8 million years old, at the dawn of the Pleistocene. This big beast is slightly younger than the still extant Hippopotamus amphibius whose fossils are found dating to around 2 million years ago. As the name suggests, the European Hippopotamus was common across Europe during the Pleistocene, from Spain, Germany, Greece and Britain. Along with a few minor differences in the teeth, the size tells the species apart from one another; H. antiquus was much larger than its cousin, around 1 and a half times bigger. It is unsure why this species grew bigger than the hippos you see today. With more resources around to support animals they can get bigger. Equally, it may have been through sexual selection: modern hippos today live in a pod of up to 30 within a territory of river with one male looking after it. Males will fight for territory. It may be that the European Hippo had larger male bulls which spread through the population. Whatever the reason, this was a very successful species and was around for almost 2million years. . This big hippo first appears in Britain during the early Middle Pleistocene, around 860,000 years ago until around 400,000 years ago. Named after the site, Cromer in Norfolk, where lots of fossils from this time were found, the Cromerian is one of the more famous early Pleistocene times. This was mainly a warm interglacial time (although as typical of the Pleistocene, it was not many years of warmth; the climate dipped and peaked as glaciers melted and grew). This was a different time in British prehistory, with giant Steppe Mammoths and Straight Tusked elephants stomping around, the lesser known sabre tooth, Homotherium, perched, waiting for its next meal, and a strange rhinoceros (Stephanorhinus hundsheimensis) munching its way through the low lying bushes. The English Channel was non-existent. Instead fertile grasslands spread from the south coast to mainland Europe. Animals migrated freely back and forth up into Britain, and back down again to suit their needs. With extreme cold glacial times following the Cromerian, the European Hippopotamus moved out of Britain, never to return. It would be another 250,000 years before a hippopotamus were to waddle into Britain again. There is an odd, possible synonym to our big hippo; Hippopotamus major. This hippo lived around the same time as our European Hippo, and at some of the same sites. There is not a lot of information is out about this species; if it is a separate species. It is possible it is a sub-species (like the Siberian Tiger is a sub species of tiger). It may even be the same species as H. antiquus. With not a lot of fossils to assess and compare, it is difficult for us to determine. Hippopotamus antiquus survived in Europe for many years, happily living in Italy, Greece, and Germany. It is a slight irony, that this, the biggest species of hippo spawned the smallest species: the extinct Cretan Dwarf Hippopotamus (Hippopotamus creutzburgi) which evolved a much smaller size to survive on an island. We are unsure as to the main reason for it extinction; possible changes in environment, or a fall in temperatures. There were extreme climatic changes throughout most of the Pleistocene and the European Hippo appears to have become extinct at the same time of many of the other mega-herbivores. This was the biggest species of hippo to evolve, and was a very successful animal throughout Europe. The Eruopean Hippo would be a delight to see today. Bigger than any hippo you would see in Africa, this would be a beast you wouldn’t disturb. Perhaps Florentijn Hofman and his giant wooden hippo should begin touring through Europe, retracing the steps of this lost giant. Written by Jan Freedman (@JanFreedman)
I would think that a hippopotamus measuring 64 feet long ( 19.51 meters ) would certainly be the "biggest ever terrestrial mammal" contest.
Just how heavy was this monster? Can we get a realistic estimation?  (01-29-2018, 12:32 PM)brotherbear Wrote: I would think that a hippopotamus measuring 64 feet long ( 19.51 meters ) would certainly be the "biggest ever terrestrial mammal" contest. 19,51 meters long ? If I take a big actual hippo of 4m long, weighing 3 tons... Your hypothetic monster would approximatively weigh: 3 tons X (19,5/4)^3 = 360 tons... I don't dare to write that...
@
With a 19,50 meters-long body, your monster hippo would be 6-7 meters height, with a full body, absolutely not slender like the sauropod dinosaurs' one. 350-360 tons ? Impossible to be alive with such mensurations, unless he lives into water all his life long. (01-29-2018, 01:48 PM)Spalea Wrote: @ A typo you suspect?
http://edition.cnn.com/2004/WORLD/europe...inthippos/
When giant hippos roamed Britain LONDON, England (CNN) -- A rare fossil find in eastern England has revealed a prehistoric period when huge hippos roamed parts of Britain. The hippos, six tonnes in weight and half as big again as their present-day relatives, roamed English swamplands with temperatures not unlike the African savannah, scientists say. Their bones have been found alongside those of horses, hyenas, deer, primitive mammoths, rodents and plants giving what London's Natural History Museum says is an unprecedented insight into an unknown "warm" period 500,000-780,000 years ago. "This is a rare and significant fossil find," says Simon Parfitt, paleontologist at the museum. "To find two hippopotamuses together is very unusual, but to find evidence of the land surface around them is exceptional. The excavation site provides a unique opportunity to study an environment that we believe has never been recognized before and that, if we don't act quickly, could be lost forever." The fossils were discovered on an inland site near Lowestoft by teams from the Natural History Museum and Queen Mary College, University of London. "Initial research undertaken by scientists indicates that the site is incredibly fossil rich and could be internationally significant," says a spokeswoman for the museum. "However, further research and urgent action is needed to carry out a rescue excavation and recover fossil specimens before the site is redeveloped in the next few months." The hippos lived in the Middle Pleistocene period when Norfolk was populated by exotic species as well as familiar plants and animals. The scientific teams says that the presence of marine molluscs together with plant remains demonstrate the land had changed from a shallow marine environment to a warm freshwater landscape. It is approximately 15 kilometers from Norfolk's present-day coast and insect fossils indicate the summer temperature at that time was 2-3 degrees Celsius warmer than today. The team says that the ancient hippopotamus were larger than today's species and weighed about six-seven tonnes, compared to modern hippos that weigh up to four tonnes. They had very prominent eyes which served as periscopes when submerged in the water. It is likely the hippos discovered died through natural causes and their bones show evidence of having being gnawed by hyenas. The excavation site reveals layer upon layer of large and small mammals, fish, molluscs, insects and plant remains, the Natural History Museum says. It adds that the precise location of the site cannot be revealed due to health and safety reasons. A selection of the fossils have gone on display at the museum's "Festival of Fossils" which began Thursday. (01-29-2018, 02:22 PM)brotherbear Wrote:(01-29-2018, 01:48 PM)Spalea Wrote: @ Yes. I try to mentally reproduce an hypothetic 19,50 meters long and 6-7 meters height hippo, and yes I deduce this weight. It seems quite impossible to me for an animal which would walk on the ground. We fall on the ancient models of sauropod dinosaurs (see the old brontosaurus' descriptions) we they are believed to live constantly into the water because of their weight. Except that your animal is even much heavier. But if somebody can contradict me... No problem !
https://twilightbeasts.wordpress.com/201...burrowers/
The burrowers Posted on November 21, 2014 by twilightbeasts To witness the full majestic sight of the Giant Ground Sloth in all it’s glory, it is best to visit at twilight. For around half an hour after the museum doors open, and then again for around half an hour just before they close, there are few visitors to distract you. Walk along the grand corridor, past exquisite remains of reptiles that once thrashed around in the warm Jurassic seas, which now line the walls watching you form their rocky entombment. At the end of the corridor, standing handsomely, proudly in the corner, is the Giant Ground Sloth; the truly magnificent Megatherium americanum. Almost a decade ago, I volunteered at the Natural History Museum, London in the fossil mammals department. Each morning, often before museum visitors were pouring in, I would admire this massive beast; its robust legs, its massive rib cage that must have once housed an enormous gut, the giant claws, and that cute looking head. Then, I would silently slink through a secret door to carry out my work with some awesome Ice Age fossils. Megatherium was a true giant. One of the largest Twilight Beasts, this was the largest sloth to have walked the Earth. The enormous creature would have towered above any human, and standing upright on its back legs, it would have easily been able to peer inside the top windows of a double decker bus. Massive, robust leg bones could have held the bulk of this beast as it reared up and fed from higher branches, or even to defend itself against predators, like a foolhardy Smilodon. Skeletal reconstructions generally have Megatherium standing, and rightly so, for this is the best way to show off the impressive size. Illustrations do vary from these sloths grabbing branches whilst standing, to crawling on all fours. Looking at the short legs, although thick and strong, they would have struggled to keep an animal this size upright permanently; if it had to travel for long distances, it is most likely that it travelled on four legs. Interestingly, most of the Megatherium footprints which have been preserved in 10,000 year old mud show this sloth to be walking on its back legs. Perhaps it was easier to walk on two legs than four along the sticky, squelchy, muddy banks? Fossils have been found across South America, from sites in Chile, Brazil, Argentina, and Uruguay. This was one of the first fossils outside of Europe to be described. Eight years after the first specimens were shipped back to Madrid, the great French anatomist, Georges Cuvier, published the first description of this extinct sloth. He correctly assigned the fossils to the sloth Order, Pilosa, and thought its giant claws were used for digging tunnels: Cuvier had created a mole bigger than an elephant! (This actually wasn’t that fanciful. Mammoths thawing out of the permafrost in Siberia were thought by the local people to have been giant burrowing moles, where they used their tusks to dig, and sadly died on exposure to the sun.). Cuvier was right in taking such an interest in the claws. Longer than your forearm, Megatherium claws on it’s hands and feet were immense. Swiping with their giant arms, and very likely causing serious damage, this was a giant not to be messed with. Some researchers suggest they were used to bring down leaves from high branches; beneficial when you are bigger and can stretch further than other herbivores. Their teeth indicate they had quite a varied diet, from leaves and fruits on trees to succulent plants closer to the ground, and these large claws may easily have been used to dig up plant roots and tubers to feed upon. There is a striking similarity between Megatherium‘s claw shape to an animal in the same Order, but with a much more specialised lifestyle. Anteaters have huge claws (resulting in their seemingly odd gait) which they use to rip open termite nests and then use their incredibly long, sticky tongues to feed solely on these nutritious insects. Recent excavations in Southern Brazil show that Cuvier’s original thoughts about a subterranean giant were actually not that far off. Incredible tunnels up to 100m long, and over a meter high have been found which were dug out by Pleistocene sloths! The soft sediment still preserves the claws marks from the creatures who painstakingly dug them out. Giant armadillos and ground sloths (possibly including Megatherium) dug into the earth, with their big claws. They clearly did spend some time underground. These palaeoburrows are remarkable evidence of the habits of an extinct creature (click here for a nice image). But the use of these burrows is still unknown. There has been little found inside the burrows to indicate if they were used for hibernating, or living in. A colleague recently suggested the possibility that the males may have patiently dug out these burrows to attract a female. They are very cleanly made, with a lot of effort, and taking a lot of time to move the sediment out of the tunnel. Perhaps Megatherium was the sloth version of the Bower Bird. It is difficult to test this today, but if true, these giants were making their own little tunnel of love! Some researchers have thought that Megatherium could have been a scavenger, using its massive bulk to steal carcasses from other predators. The Giant Ground Sloth would have had no problems scaring away any animal if it chose to scavenge half eaten kills from other predators. There is little real evidence to say the diet was supplemented with fresh flesh, apart from the massive claws. But the claws are not enough. You need sharp teeth to cut the meat and chew it. Megatherium lacked any sharp slicing teeth. The molars were ridged like many herbivores for chomping up vegetation. In fact, this giant lacks the front incisors which are normally used for nipping grass or leaves; instead, there may have been a very long tongue like a giraffe, or big, prehensile lips, similar to a rhinoceros. Although fur has been found preserved in caves for Mylodon, none has yet been found for Megatherium. It is possible the fur was long and shaggy, not too dissimilar to the preserved fur from Mylodon, or the thick long fur of sloths alive today. The gorgeous tree sloth has long thick hair, and is known to harbour green algae, that makes it look green, blending in beautifully with the surrounding forest. There is a hidden world within the fur. It teems with insects, parasites, and fungi. Whatever the colour, or thickness of Megatherium’s fur, this giant was very likely a walking island for dozens of tiny species. Along with the extinction of Megatherium presumably most of these tiny animals who called it home vanished too. It is often strange to think that there are so many species that have existed on our planet that we will never know were there. From trundling around South America for over 2 million years, the great Megatherium vanished fairly recently, around 10,000 years ago. Towards the end of the Pleistocene, the climate was changing, which had an effect on so many of the Twilight Beasts. From the warm temperate, arid to semi-arid environments the Giant Ground Sloth was at home in, the environment changed to cooler and drier with more grasses. For the ginormous browsing herbivore, the changing landscape was a big problem. On top of their shrinking natural habitat, a new creature was on the scene; Homo sapiens. In Argentina, the sites of Arroyo Seco and Paso Otero have revealed Megatharium americanum bones, alongside human artifacts. No cut marks have been found on the bones yet. But, with spears and other projectiles, humans could have easily, and safely, attacked this giant. Large mammals will often have large gestation periods. Elephants, for example, carry their baby for around 2 years; for a mouse, it is around 20 days. With Megatherium under stress from a changing environment, and additional pressures from being hunted, their long gestation time would not have allowed them to increase their numbers quickly enough. Bones of Megatherium were sought after by the Victorians. Along with Mammoth, the Giant Ground Sloth was a creature to behold and admire. Soon, the great dinosaurs stole the lime light, pushing the Giant Ground Sloth back into obscurity. Whilst walking past the magnificent skeleton at the Natural History Museum, more than a dozen times I have heard children, and adults, excitedly, but rather sadly, exclaim, ‘Wow! Look at this dinosaur!’ Megatherium americanum is a beast dear to my heart, and needs no title of ‘dinosaur’ to beef it up. Written by Jan Freedman (@JanFreedman)
Doing the crawl? https://twilightbeasts.wordpress.com/201...the-crawl/
Posted on April 25, 2016 by twilightbeasts The life aquatic has lured many animal groups back into its liquid embrace. Marine iguanas, penguins, whales and dolphins, sea-cows and manatees, seals and sea-lions all returned to the sea from land (and air!) adapted forms. It makes a lot of sense- the littoral is a pretty rich zone that surely tempted those that could take advantage of it. From there it is but a short evolutionary jump back into the blue. Many animals are already halfway there, with one hoof in each camp. Think of the hippo, the beaver, the desman, the otter. Given the wide variety of creatures that have done this, it can be fun to imagine future forms. Bat-penguins? River-antelopes? Water-wombats? Flights of fancy like this have a long pedigree. Darwin himself, in The Origin mentions: “In North America the black bear was seen by Hearne swimming for hours with widely open mouth, thus catching, like a whale, insects in the water. Even in so extreme a case as this, if the supply of insects were constant, and if better adapted competitors did not already exist in the country, I can see no difficulty in a race of bears being rendered, by natural selection, more and more aquatic in their structure and habits, with larger and larger mouths, till a creature was produced as monstrous as a whale.” Sea-bears? Why not! As usual, nature is not only weirder than we imagine, but weirder than we can imagine. Perhaps the most unlikely group ever to have flirted with the aquatic lifestyle was only recently recognised from Pliocene fossils: Thalassocnus sp. Thalassocnus is, and I can’t really believe this either, a giant marine sloth. The first clues to this puzzle were due to some flukes of taphonomy. The Pisco Formation in Peru is a richly stratified Miocene and Pliocene site with amazing preservation of marine creatures including articulated whales, dolphins, crocodiles, fish, sharks, and dugongs. And giant sloths. Now, you don’t usually expect to find giant sloths in a strictly marine site. But these sloths were quickly identified as something pretty special indeed. Detailed study has shown that not only were these behemoths at home in a marine shore environment, they had picked up some pretty cool adaptations along the way. Neater still, the layers of the Pisco Formation contains thalassocnine sloths from multiple timepoints between the Miocene and Pliocene, showing how some of those characters changed through time. It seems that this shallow prehistoric sea was prone to occasional algal red blooms that regularly poisoned everything, leaving articulated skeletons behind. Through these fossils, you can actually see evolution happening. In the ribs and limbs you find a gradual thickening of the cortical bone; an increase in density that helped to counteract the natural buoyancy of an air-breathing mammal. There is also a gentle elongation of the premaxillae and mandible symphysis, creating a long and wide snout, better adapted to munching water-weeds. The earlier species of thalassocnine have lots and lots of striae on their weird, peg-like sloth teeth- indicating that they were taking in a lot of sand while they were feeding, probably due to wading in shallow water where any movement would stir up lots of sediment. The later species don’t have this. Suggesting that they were feeding further out to sea, where sand wasn’t an issue.
https://twilightbeasts.wordpress.com/201...the-range/
A home on the range Posted on September 11, 2014 by twilightbeasts Imagine an igloo. Now picture it with a crash helmet poking out the front, and a medieval spiked club sticking out the back. Elevate that image on four stubby legs, convert it into bone and flesh and you have a good approximation of a glyptodont. For my money the weirdest extinct animal that humans encountered on their global tour. Relatives of sloths and anteaters, glyptodonts are grouped with them in the taxonomic superorder Xenarthra due to shared features such as a lack of tooth enamel, extra articulations on their vertebrae, and (presumably) males with internal testicles. Found all over South America, having evolved in isolation there during its long history as an island continent, the glyptodonts ranged as far north as South Carolina during the Pleistocene. At least three genera are known to have survived up to the late Pleistocene: Panochthus, Glyptodon(Glyptotherium), and Doedicurus. Despite superficially looking identical, these three genera packed their punches in pretty different ways. Glyptodon had a tail made from concentric rings of spiky bone with a fringe of points around its carapace. Doedicurus had a long cylindrical tail club with enigmatic circular depressions over the end (probably indicative of enormous keratin horns that grew during life). Panochthus was a mix of spiky tail rings and a cylindrical, horny, club. This was the business end of the glyptodonts and ensured that an adult probably had no natural predators. However, the young ones were hunted- there is a famous subadult Glyptotherium texanum skull from Southeastern Arizona that has two neat, elliptical holes punched in the top. They exactly match the only predator with elliptical canines from that timeframe- Smilodon fatalis. Interestingly, this method of attack is sometimes used by the extant jaguar (Panthera onca), which will kill capybara and other medium-sized prey by piercing the braincase through the ears. Could jaguars have honed this method on another, now extinct, species that formerly shared its range? With such powerful predators around, growing glyptodonts would have been glad of their mammalian thagomizers. It seems likely that as well as a defensive weapon, the tail clubs were also used in intraspecific competition. Some carapaces show traces of damage that match the size and shape of another animals tailclub. Researchers have calculated that a single blow from the tail of one species, Doedicurus clavicaudatus, could produce 60 kiloNewtons of force (by way of comparison, 4 kiloNewtons is enough to fracture an average human femur). There is even evidence that the tail evolved to produce an offensive weapon analogous to a baseball bat, with a centre of percussion at the exact point where the spikes began, allowing it to transmit maximum force with each blow. The glyptodonts appear incredibly weird to modern eyes. How might they have been viewed by the paleoindians who encountered them? There is surprisingly little “good” archaeology on interaction between them and man. However, some less than charming vignettes are suggested. The famous palaeontologist Florentino Ameghino claimed to have found two examples of the carapaces of glyptodonts used as temporary shelters! He recounts finding the detritus of occupation: flints, cutmarked bones, and charcoal around a glyptodont shell excavated close to the town of Mercedes, by Buenoes Aires in Argentina. He surmised that the glyptodont had been hunted by people, who then dug a small pit and roofed it with the carapace to provide shelter on the treeless pampas. There is also evidence of the use of glyptodont osteoderms (the hexagonal bones that make up the carapace) as grave offerings (at the site of Arroyo Seco 2 in Argentina). Such an incredible creature, and it stopped you getting sunburnt too. Written by @DeepFriedDNA |
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