Named just a year after Megalosaurus, in 1825, Iguanodon has remained a fairly iconic dinosaur ever since.
Discovered in a different region of Southeast England, its fossilized teeth were soon recognized as being similar to those of modern iguanas – but much much larger. Partial skeletal remains were initially reconstructed as belonging to a gigantic herbivorous lizard, with what was thought to be a horn placed on the tip of its nose.
1850s
The Victorian Crystal Palace statuesofIguanodon depicts a more bulky reptile with a nose horn, a toothless beak at at the front of its jaws, scaly skin, thick upright legs and hoof-like claws. Much like the Megalosaurus of the time it’s really not nearly so bad of a reconstruction as it’s often accused of being, showing a surprisingly naturalistic and almost mammal-like interpretation of these animals compared to later portrayals.
Technically the particular “Iguanodon” species at Crystal Palace has more recently been renamed Mantellisaurus atherfieldensis, but it was considered to be Iguanodon at the time so it’s included here anyway.
1880s-1960s
A massive discovery of the remains of nearly 40 Iguanodon individuals in a coal mine in Bernissart, Belgium, revealed the full anatomy of these dinosaurs for the first time. Much more well-preserved and complete than the patchy English material, these larger Iguanodon bernissartensis eventually became the official type species for the whole genus – a standard used to help determine whether similar-looking fossils are Iguanodon or not.
The Bernissart specimens were restored as bipedal animals in an upright kangaroo-like pose, with their tails dragging behind them acting like a tripod to prop them up. What had previously been the single “horn” was finally realized to instead be a thumb spike on each hand, interpreted as a defensive weapon against predators.
This image of Iguanodon persisted for decades, with a giraffe-like long prehensile tongue sometimes also depicted (including a particularly bizarre interpretation of it sticking out through a hole in the lower jaw!).
2020s
TheDinosaur Renaissance in the late 20th century corrected Iguanodon’s posture to hold its body horizontally, and it was eventually recognized as being capable of both bipedal and quadrupedal movement. Juveniles were found to have walked more on their hindlimbs, while adults spent more time on all fours but were still capable of running bipedally when they needed to.
We now have fossils of Iguanodon from across much of Europe during the Early Cretaceous, about 126-122 million years ago. Our modern view of this animal is a heavily built ornithopod that grew to around 9m long (~30’), with a horse-like head, a large keratinous beak at the front of its jaws, chewing teeth further back, and cheeks covering the sides of its mouth. Its chunky forelimbs each had a large thumb spike, hoof-like claws, and a prehensile grasping pinky finger, while its powerful hindlimbs ended in three-toed vaguely bird-like feet.
Soft tissue preservation discovered in related hadrosaurs suggests it probably also had a very bulky body with a thick heavily muscled neck and tail, and possibly an ornamental “frill” running along its back. Skin impressions show a covering of numerous tiny pebbly scales, generally too small to have been visible from a distance.
This is how I feel about Joshua Trees. They and avocado trees produce fruit meant to be eaten and dispersed by giant ground sloths. Without them, the Joshua Trees’ range has shrunk by 90%.
(my own photos)
Not only they, but the entire Mojave ecosystem is still struggling to adapt since the loss of ground sloth dung. their chief fertilizer.
Many, many trees and plants in the Americas have widely-spaced, extremely long thorns that do nothing to discourage deer eating their leaves, but would’ve penetrated the fur of ground sloths and mammoths. Likewise, if you’ve observed a tree that drops baseball or softball-sized fruit which lies on the ground and rots, like Osage Oranges, which were great for playing catch at my school, chances are they were ground sloth or mammoth chow.
You can read about various orphaned plants and trees missing their megafauna in this poignant post:
Gingkos as they look today have spent more time coexisting with dinosaurs than they have without! Their fruit doesn’t do well because they evolved before chewing, masticstion, evolved!
wait dinosaurs didn’t chew?
Like modern reptiles, they could move their jaws up and down, but most of the effectiveness of chewing comes from moving your lower jaw sideways and back-and-forth to grind food between the surfaces of your teeth. Doing that requires a special jaw joint that exists in mammals, but not in other vertebrates (see stages 19 to 23 here). Hadrosaurs (”duck-billed dinosaurs”) might have had special hinged tooth batteries that ground against each other in a similar way – which could have accounted for their success, they appeared in the Cretaceous and basically replaced most other large herbivorous dinosaurs – but this in fact happened after ginkgoes appeared.
(The first reblogger in the chain is mistaken – beetles first appeared in the Permian, over a hundred million years before magnolias.)
The fanciful and whimsical Paleoart of E. Boyd Smith (possibly my favorite old paleoartist after Knight and Burian - though he wasn’t one by profession). This book from 1944, “So Long Ago”, is a fun romp through prehistoric time that showcases the evolution of life on land. Its age means that much of the animals are heavily dated, and you can see many homages to other artists or hypotheses from the times. I do not yet own the book, but from the descriptions of the photos and subsequent searching, this appears to be a short story about a scientist who takes a curious boy (his son? museum patron?) and his cat on a tour of geologic time - which is just a cool idea for a story. Definitely needs a modern update. Hmmm…
My latest clamuscriptis published in Palaios, coauthored with my advisor Matthew Clapham! It’s the first chapter of my PhD thesis, and it’s titled “Identifying the Ticks of Bivalve Shell Clocks: Seasonal Growth in Relation to Temperature and Food Supply.” I thought I’d write a quick post describing why I tackled this project, what I did, what I found out, and what I think it means! Raw…
In undergrad, I felt like my school and internship were training me to be two different types of researcher. At USC, I was majoring in Environmental Studies with an emphasis in Biology. It was essentially two majors in one, with a year of biology, a year of chemistry, a year of organic chem, a year of physics, molecular biology, biochemistry, etc. On top of that, I took courses on international…
This lower jaw dates back to the Jurassic era and belongs to: @mike_the_pliosaur. This is only a fragment of the jaw, more has been preserved extending the whole length. Mike would have been an incredible predator, with so many teeth to catch and devour his prey. . Follow @neojurassica to see more #prehistoric wonders! . www.neojurassica.com Dinosaur Specialists Genuine Fossils ⚙️ Display Customisation Free UK Delivery ✈️ International Delivery . #MikeThePliosaur #pliosaur #plesiosaur #plesiosaurs #fossils #fossil #extinct #extinction #fossilhunting #yorkshirefossils #dinosaur #dinosaurs #dinosaurbone #teeth #predator #nature #naturalhistory #history #archeology #geology #paleontology #palaeontology #paleobiology #science #jurassic #jurassicpark #jurassicworld #neojurassica #prehistory https://www.instagram.com/p/CQhKpRitQsf/?utm_medium=tumblr
These are Pliosaur phalanges, the finger bones of a large marine predator that lived in the Jurassic era. The bones belong to @mike_the_pliosaur, a hauffiosaurus from the Yorkshire Coast of Britain. . Follow @neojurassica to see more #prehistoric wonders! . www.neojurassica.com Dinosaur Specialists Genuine Fossils ⚙️ Display Customisation Free UK Delivery ✈️ International Delivery . #pliosaur #plesiosaur #marinereptile #dino #dinosaur #dinosaurs #dinosaurbones #MikeThePliosaur #extinct #evolution #fossil #fossils #fossilfriday #jurassic #jurassicpark #jurassicworld #neojurassica #mesozoic #naturalhistory #nature #naturephotography #palaeontology #paleontology #geology #science #paleobiology #discovery #archaeology #museum https://www.instagram.com/p/CPa_x7atJeF/?utm_medium=tumblr
One of the dorsal vertebrae belonging to Mike (@mike_the_pliosaur). This #fossil dates back over 175 million years to the Jurassic era, when #dinosaurs still roamed the Earth. Mike’s skeleton was found along the Yorkshire coast of Britain and was an exceptional discovery. . Follow @neojurassica to see more #prehistoric wonders! . www.neojurassica.com Dinosaur Specialists Genuine Fossils ⚙️ Display Customisation Free UK Delivery ✈️ International Delivery . #MikeThePliosaur #pliosaur #plesiosaur #plesiosaurus #extinct #marinereptile #dinosaur #fossils #fossilhunting #palaeontology #paleontology #geology #science #paleobiology #dinosaurmuseum #naturalhistorymuseum #naturalhistory #nature #history #archeology #discovery #prehistory #prehistoricanimals #naturalworld #jurassic #jurassicworld #neojurassica https://www.instagram.com/p/CPNZzp3N6qt/?utm_medium=tumblr
Little paddle belonging to a juvenile Ichthyosaur. The small skeleton was found near Lyme Regis, a historic town on Britain’s Jurassic Coast where pioneer of palaeontology, Mary Anning, once lived. This skeleton is near complete and more photos will be coming soon once it’s fully prepared. . Follow @neojurassica to see more #prehistoric wonders! . www.neojurasssica.com Dinosaur Specialists Genuine Fossils ⚙️ Display Customisation Free UK Delivery ✈️ International Delivery . #ichthyosaur #ichthyosaurus #marinereptile #dinosaur #dinosaurs #dinosaurbones #dinosaurskeleton #skeleton #extinct #evolution #fossils #fossil #fossilhunting #fossilfriday #prehistory #naturalhistory #nature #history #archeology #palaeontology #paleontology #paleobiology #science #stem #jurassic #jurassicpark #jurassicworld #jurassiccoast #neojurassica https://www.instagram.com/p/CPImKTCNSvw/?utm_medium=tumblr
AbstractThe late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. …
We present, to our knowledge, the first global analysis of this extinction based on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132 000 years BP and the late Holocene 1000 years BP, testing the relative roles played by glacial–interglacial climate change and humans.
We show that the severity of extinction is strongly tied to hominin palaeobiogeography, with at most a weak, Eurasia-specific link to climate change. …
IMAGE Global maps of late Quaternary [a, b] large mammal extinction severity, [c] hominin palaeobiogeography, [d] temperature anomaly and [e] precipitation velocity. [More detail here…]
Remarkable spider with a tail found preserved in amber after 100 million years
An extraordinary new species of arachnid, resembling a spider with a tail, has been discovered in amber from Myanmar (formerly Burma), of mid-Cretaceous age, around 100 million years ago.
The finding is described in a paper appearing Monday in Nature Ecology & Evolution by an international team including Paul Selden of the Paleontological Institute and Department of Geology at the University of Kansas and colleagues from China, Germany, Virginia and the United Kingdom.
“There’s been a lot of amber being produced from northern Myanmar and its interest stepped up about ten years ago when it was discovered this amber was mid-Cretaceous; therefore, all the insects found in it were much older than first thought,” said Selden. “It’s been coming into China where dealers have been selling to research institutions. These specimens became available last year to Nanjing Institute of Geology and Paleontology.”
The new animal resembles a spider in having fangs, male pedipalps, four walking legs and silk-producing spinnerets at its rear. However, it also bears a long flagellum or tail. No living spider has a tail, although some relatives of spiders, the vinegaroons, do have an anal flagellum. Four new specimens have been found, and all are tiny, about 2.5 millimeters body length, excluding the nearly 3-millimeter-long tail.
“Any sort of flagelliform appendage tends to be like an antenna,” the KU researcher said. “It’s for sensing the environment. Animals that have a long whippy tail tend to have it for sensory purposes.”
This exciting new find confirms a prediction made a few years ago by Selden and colleagues when they described a similar tailed arachnid, which resembled a spider but lacked spinnerets. These animals, from the much older Devonian (about 380 million years ago) and Permian (about 290 million years ago) periods, formed the basis of a new arachnid order, the Uraraneida, which lies along the line to modern spiders.
“The ones we recognized previously were different in that they had a tail but don’t have the spinnerets,” said Selden. “That’s why the new one is really interesting, apart from the fact that it’s much younger—it seems to be an intermediate form. In our analysis, it comes out sort of in between the older one that hadn’t developed the spinneret and modern spider that has lost the tail.”
The new animal, called Chimerarachne after the Greek mythological Chimera, a hybrid creature composed of the parts of more than one animal, lies one step closer to modern spiders on account of its possession of spinning organs.
Selden said little of the tiny spider’s day-to-day behavior could be determined.
“We can only speculate that, because it was trapped in amber, we assume it was living on or around tree trunks,” he said. “Amber is fossilized resin, so for a spider to have become trapped, it may well have lived under bark or in the moss at the foot of a tree.”
While the tailed spider was capable of producing silk due to its spinnerets, Selden said it was unlikely to have constructed webs to trap bugs like many modern spiders.
“We don’t know if it wove webs,” said the KU researcher. “Spinnerets are used to produce silk but for a whole host of reasons—to wrap eggs, to make burrows, to make sleeping hammocks or just to leave behind trails. If they live in burrows and leave, they leave a trail so they can find their way back. These all evolved before spiders made it up into the air and made insect traps. Spiders went up into the air when the insects went up into the air. I presume that it didn’t make webs that stretched across bushes. However, like all spiders it would have been a carnivore and would have eaten insects, I imagine.”
Selden said the spider’s remote habitat made it possible that tailed descendants may still be alive in Myanmar’s backcountry to this day.
“We know a lot about the Burmese biota during the Cretaceous,” he said. “It was a pretty good tropical rainforest, and there are a great many other arachnids we know were there, particularly spiders, that are very similar to the ones you find today in the southeast Asian rainforest. It makes us wonder if these may still be alive today. We haven’t found them, but some of these forests aren’t that well-studied, and it’s only a tiny creature.”
“Though most scientists believe that a series of volcanic eruptions, occurring in large pulses over a period of a million years in what is now Siberia, were the primary cause of the end-Permian extinction, the lag between the land extinction in the Southern Hemisphere and the marine extinction in the Northern Hemisphere suggests different immediate causes.”
![mucholderthen: Global late Quaternary [132,000 to 1,000 years ago] Megafauna Extinctions linked to](https://64.media.tumblr.com/104acfb5a9a09f60a9a4e69dfbe911da/tumblr_n8s612mmnq1rhb9f5o2_r1_1280.jpg "mucholderthen: Global late Quaternary [132,000 to 1,000 years ago] Megafauna Extinctions linked to")
