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Description
Edmontosaurus annectens

Hadrosaurids were a cornerstone of the Cretaceous period ecosystems across the northern hemisphere. They ranged in size from around 20 feet in length to as long as 40 feet, and possibly some species reaching more than 50 feet. By the end of the Cretaceous, American Hadrosaurs reached their apex in the form of a genus that goes by many names from Anatosaurus, Trachodon, Anatotitan, however, the most well-known binomial name being Edmontosaurus annectens.

History of Discovery:

It was discovered back in the 1882 by Dr. J. L. Wortman and R. S. Hill in South Dakota. They were on an expedition contracted E.D Cope of Philadelphia. At this time, he and his rival Othniel Marsh were locked in the infamous bone wars. The find consisted of a very well-preserved skull, and most of the animal was present except for sections of the torso. Cope sent it to the American Museum of Natural History and described as AMNH 5730. E.D. Cope described it as Dicolonius mirabilis. A species of Hadrosaur described by his mentor, Joseph Leidy. The generic name means "Double Sprout" from the Greek language, the species name, means marvelous. Today, it's still on display at the American Natural History Museum in New York City.

In 1892, while the Bone Wars was winding down, Marsh described a specimen of Hadrosaur called "Claosaurus annectens". He referred it to the genus he had discovered called Claosaurus, which was a basal Hadrosaur from Kansas. The genus name derived from "Clao" greek for Broken and Lizard because the type species C. agilis looking very fragmented when discovered. The specific name for this species "annectens" literally means "connected". Why he named the specimen this is unknown, as characteristic at this stage of the Bone Wars, Marsh sought to name as many species as he could to outrank his rival, Cope. The finds themselves consisted of a partial skull and fragmentary skeleton. A following specimen consisted of another complete skull. Today they are in the collection of the Yale Peabody Museum.

Edmontosaurus itself was named by Lawrence Lambe in 1917 when he discovered Edmontosaurus regalis in Canada. Edmontosaurus' name needs no explanation, "Edmonton's Lizard" as the formation, the Horsehoe Canyon formation was in the Edmonton group in Alberta.

The other species, E. annectens, had been—throughout the 1900s, it has been assigned to various and now outdated/dubious genera such as Anatotitan, Anatosaurus, Trachodon, and Claosaurus, to name a few. Various specimens assigned to various genera were either found to be dubious, invalid or not belonging to the genera.

Edmontosaurus annectens modern taxonomic position really started in the early to mid-1980s. It was called "Anatosaurus," literally meaning "Duck Lizard". However, Michael K. Brett-Surman researched this animal for his graduate studies. He found many similarities between Edmontosaurus and Anatosaurus, and they were subsumed into Edmontosaurus annectens, whereas the larger and more long-jawed Anatotitan copei warranted its own species.
In 2011, Canadian paleontologists David Evans and Nicolás Campione conducted studies on Anatotitan skulls and compared them to Edmontosaurus. They found that the increased length of the skulls in Anatotitan was due to ontogenetic changes as the animal matured. Thus, Anatotitan is now believed to have been a mature Edmontosaurus annectens.

Description:

The earliest known species was Edmontosaurus regalis. Ranging around 30-39 feet in length and living almost exclusively in what is today Canada, with a distinct fleshy comb-like structure on its head. Whether or not E. annectens had a fleshy comb is unknown. However, there were some differences between the two species. For one, the skull was more elongated in general compared to E. regalis. Especially as it reached older age (as will be discussed) and it was also more robustly built compared to any other American Hadrosaur.

Weighing in at around 7 tons on average, there are specimens that exceed that size with weights up to 11 or possibly 12 tons recorded in specimens like X-rex/MOR 1142. The animal was so massive, paleontologists thought it was a T.rex fossil, but we now know this animal belongs to a Edmontosaurus annectens. Along the back of the aforementioned specimen, it looks like there is evidence of distinctive half-moon shaped scales running down the back. Found on similar animals like Brachylophosaurus, it suggests that this feature may have been found across the entire family of Hadrosauridae.

These dinosaurs are often called "Duck-Billed Dinosaurs". The moniker is believed to have originating from Cope noting the skulls' wide muzzle and flattened tip at the end. However, Cope could not have known this as softer parts of the dinosaur had not survived fossilization with the specimens he and Marsh had found.

Given the size of these dinosaurs, they were mainly quadrupedal, but, could have been able to rear up and run on their hind legs if needed. The proper term is facultative bipeds, a form of locomotion exclusive to dinosaurs, with the only decent modern analogue being pangolins. However, the pangolins are far more quadrupedal than bipedal.

As previously mentioned, the skull was elongated in terms of length. However, as the dinosaur matured, it became both lower in terms of skull structure and far more elongated. This is something that is seen with a lot of saurolophines, such as Saurolophus itself. Namely the Mongolian species where an entire growth series has been pieced together, and E. annectens is no different. As mentioned in its history, largest and longest jawed specimens traditionally grouped as Anatotitan (meaning Giant Duck), are now believed to be E. annectens.
Classification:

E. annectens is a member of the Hadrosauridae family, classified in the saurolophini subfamily. This was a group of Hadrosaurs found across Asia and America. Famous members included Saurolophus itself and the giant Shantungosaurus. It's believed that this was the most derived member of the saurolophines by the end of the cretaceous next to the giant Shantungosaurus.

As previously mentioned, E. regalis was the first member of the genus to be classified. Given the complexity of taxonomy in this species, E. regalis is the type species. Some paleontologists have suggested to split up the genus with either Anatosaurus or Anatotitan. However, in all taxonomic studies in the intervening years, all have had E. annectens classified as a species of Edmontosaurus. There is a supposed third species that was at first classified as Ugrunaaluk kuukpikensis, named in 2015 and from Alaska's Prince Creek Formation. However, paleontologists noted this animal is indistinguishable from any other species of Edmontosaurus. Thus, it's generally believed to be either a northern occurrence of E. annectens or a late surviving E. regalis.

It's believed that E. regalis was the precursor to E. annectens. As the climate changed from the Campanian to Maastrichtian, the more diverse hadrosaurs being the lambeosaurini and parasaurolophini seem to vanish from the fossil record in more northern parts of North America. E. regalis would die out by 70,000,000 years ago. By the end of the Cretaceous, only Edmontosaurus annectens have be found in parts of the Northern states and Canada. Why this is the case is unknown, possibly because they were larger, these animals evolved convergently with T.rex or maybe they were just better adapted to this environment as they evolved into the last days of the dinosaurs.
Diet and Implied Feeding:

When Edmontosaurus was first discovered, it was thought that they ate soft water planets with their distinctive bill-like shape on, similar to their namesakes, ducks, and waterfowls. A very common trait of early paleoart with these animals being portrayed by famous paleoartists such as Rudolph Zallinger and Charles Knight as sluggish, semi-aquatic animals dipping their heads into the water to feed on water plants.

However, modern discoveries have painted a very different picture of how these animals ate.

Hadrosaurids, also known as "Duckbills," had distinctive snouts resembling bills of waterfowl. However, recent finds have challenged this view. First and foremost, they have teeth in their jaws, vastly different from ducks who use their beaks to strain the plant matter from their environment. They had massive batteries of teeth that show evidence of a chewing form of processing food.

John Ostrom, most famously known for discovering Deinonychus and noticing the bird-like connection between Dromaeosaurs and Archaeopteryx, prior to this, his masters was on the jaw morphology of various hadrosaurs. Most of the paleontological community knew these animals could chew. Ostrom however noticed something very different when he wrote his thesis in 1964. The teeth formed a distinctive grinding surface that, for a reptile could break down plant material in a method far more efficient than any other reptile. The animals efficiency in processing food was on par with some mammals. Moreover, the teeth showed more evidence of wear than Marsh and Cope had thought. They weren't straining food, they were eating very tough vegetation. This was the first inkling Ostrom had that these animals were probably more than sluggish animals.

Seemingly vindicating Ostrom, an extraordinary fossil paints an entirely different picture of this awesome animal. A specimen described in 1970, just when the Dinosaur Renaissance was starting to pick up momentum, shows these animals were anything but "duck-billed". A keratinous down-turned, hoe-like bill structure called a "rhamphotheca". It was likely designed to rake, clip, or strip the vegetation from its environment.
In terms of diet, recent analysis reveals that Edmontosaurus was a grazer of ferns and horsetail, but it also could have eaten from tougher vegetation like conifers. In general, it was probably a generalist in its environment. With its batteries of teeth, it made it a very efficient chewer of vegetation. Its jaws opening and closing in a clam-like fashion, masticating the material in its jaws.

No evidence of feathering or any filamentous structures have been found on these animals. However, the skin of these dinosaurs consisted entirely of scales. They were fine and small in a structure some have described as being akin to an "asphalt pavement" of sorts. More prominent scales were found up on the neck and parts of the leg as well.

Habitat and Social Behavior:

The most well-known environment Edmontosaurus was from is known as Hell Creek. Dating to around 68-66,000,000 years ago. Today, it is parts of Montana, North and South Dakota and Wyoming. The foothills of the Rockies and the badlands of the United States. When Edmontosaurus was around, the environment would have been nothing like it is today.

Hell Creek was a flood plain environment interspersed with conifer forests and fern prairies. Conifers such as Sequoia have been found in this environment. Cypress trees dominating the wetlands. There was also some more prevalent modern foliage around like oak, pine, and other hardwood trees. Flowering plants were abundant in this environment too. Edmontosaurus would have been found roaming the environment feeding upon the foliage in the region. The most prevalent environment attributed to Edmontosaurus that have been found would have been lowland swamps. The banks of these swamps would have been lined with cycad, tree ferns and horsetail. They would have used their prominent beak to clip plants from fronds from stems or branches.

Bonebeds from Hell Creek show multiple individuals found together. It's been suggested these were social dinosaurs dwelling in herds. Both this find and several other hadrosaurs have also been found fossilized together including Saurolophus from Mongolia, Maiasaura in Montana, Edmontosaurus regalis, its close cousin found in Canada, and finally Parasaurolophus, Lambeosaurus and Corythosaurus also found in a massive bonebed Canada. So, social behavior in these dinosaurs is not beyond belief.

Like the aforementioned Maiasaura, it's believed that these dinosaurs were reared in nesting colonies and probably had parents bring food to the hatchlings. While no nests attributable to Edmontosaurus have been found, its generally believed that Hadrosaurs had similar growth with juveniles having ungainly limbs and unable to leave the nest till they matured sufficiently.

Edmontosaurus was the second most common herbivore in the region. With 20% of the fossils recovered from Hell Creek being Edmontosaurus. Only Triceratops exceeds it in number with more than 40% of the fossils from Hell Creek being Triceratops. Alongside the three-horned face, smaller herbivores such as the agile Thescelosaurus, the ostrich-like Struthiomimus and thick-headed Pachycephalosaurus existed alongside it. Another titanic herbivore alongside Triceratops was the armored Ankylosaurus and smaller non-clubbed ankylosaur, Denversaurus.

Predators would have been the small Dromaeosaur, Acheroraptor perhaps preying on baby Edmontosaurus or their eggs if they can get to them in the nest. The larger predator, Dakotaraptor would have hunted babies or maybe juvenile Edmontosaurs right out of the nest. However, these two would have paled in comparison to the largest apex predator in North America, Tyrannosaurus rex. adolescent T. rex could have taken down juvenile animals and their titanic parents would have hunted Edmontosaurs of varying sizes. Their only defense would have been their tight social structure as well as probably their bulk. The evidence of Tyrannosaurus rex hunting Edmontosaurus is amazing (as will be discussed) as various fossils had both bite marks and scars have been found on their bones.

Fossils and Mummies:

Edmontosaurus has had a lot of well-preserved specimens unearthed over the years. Not just skulls and skeletons, but dinosaur mummies.

Where not just bones, skin, tissue, and occasionally even organs and keratinous structures survive across the eons, we've been able to get a much better view of what these titanic vegetarians looked like. In fact, the first Dinosaur mummy discovered was an Edmontosaurus annectens. Discovered in 1908 by paleontologist Charles Sternberg and his sons in the badlands of Wyoming. While it wasn't the best-preserved, it offered the first glance at what these great reptiles looked like.

Another find was LACM 23502, the mummy that preserved the keratinous beak. Contrary to Cope's view and the common moniker, the beak was not duck shaped, but had a keratinous rhamphotheca that formed a hooked shaped extension that also has implications in their diet and how they fed (as will be discussed). Unfortunately, while preparing the fossil, part of the rhamphotheca was chipped off as the preparator was not sure what the material was until half of it was knocked off.

However, perhaps the most complete was discovered in 1999 by then Student Tyler Lyson in North Dakota. It was nicknamed "Dakota" after its home state. He knocked off a piece of what he thought was just sandstone. Bringing it back to his home, he brushed the dust away and late at night, he realized: this was skin of a dinosaur. He knew it was a Hadrosaur as skin impressions have been found before, but nothing could compare to this. The skin had retained its 3D shape and hadn't collapsed in around the bone.
It's probably among the most complete of all Dinosaur Mummies. As far as studies go, not much has been published on this specimen, other than a couple of pictures of the animal; it may be years before seeing more information on this specimen.
However, pictures from the Mummy have given some newer views on this animal; among the most recent was that they had a hoof-like structure forming around the ground-contacting metacarpals. Digit 3 was the largest weight-bearing foot claw that contacted the ground. Digit 2 had a claw as well, digit 4 was probably just a thin pinky finger that was probably just vestigial and had no claw whatsoever.

As previously mentioned, T. rex dwelled alongside Edmontosaurus annectens. Fossil specimens of Edmontosaurus show bite marks and wounds inflicted by Tyrannosaurus rex. Scraping bite marks on the bones and healed up vertebra indicated that T.rex both fed upon and preyed upon Edmontosaurus. Specifically, DMHH 1943 which consists of a mature juvenile Edmontosaurus had a piece of tail vertebra bitten off. The injury on the vertebra healed. Meaning the Tyrannosaurus probably ambushed the dinosaur got a hold of the tail but was able to flee. A failed hunt on behalf of the Tyrannosaur.
Even more amazing was a study from 2013 conducted by David Burnham et al. that turned up an Edmontosaurus fossil with a Tyrannosaur tooth embedded in the bone. The injury healed around the bone and preserved it in the fossil.

Extinction:

Edmontosaurus vanished along with all non-avian dinosaurs at the end of the Cretaceous. When the infamous asteroid wiped all non-avian dinosaurs off the planet. The legacy this dinosaur would leave behind is one of taxonomic confusion, but also a small, but important footnote in terms of how paleontologists would eventually view dinosaurs as warm blooded active dinosaurs.

Furthermore, the discoveries of dinosaur mummies would show us that these animals were far more unique then at first glance. Not as swamp-dwelling, semi-aquatic giant ducks, but land-dwelling, tough-green chomping dinosaurs of Hell Creek.
___________________________________________________________________________________________
Okay, decided to re-write this profile as the old draft was driving me crazy.

This... actually was a lot easier to do then the first one. For one, the modifications to the back were a lot easier to do then I remember. Furthermore, I modified the hands a lot more adding the nail to the foot, making the hoof more prominent, and the nails and pinky, not as much. Of course, I added a growth series, but I thought I'd skip that here.

I decided to show juvenile T.rex harassing a group of Edmontosaurus and show the size of the adult Edmontosaurus. Yes, I could have gone for a T.rex ambush, but I wanted to emphasize the scale of these dinosaurs.

As previously said, this will be in Past Meets Present, and I've got some scenes planned out along with a T.rex. So, I look forward to that...

Also, as I also said, I'm still calling them Edmontosaurus and not Anatosaurus. And why Anatosaurus is making a comeback? IDK why. It really doesn't make any sense to me because, to be honest, the name of a dinosaur is completely subjective.

Data on how these animals ate was from Darren Naish's Blog:
Enough with the "Duck-Billed Dinosaurs" - Scientific American Blog Network

The length of these giants I took mainly from Paleop , and I made a rough approximation in terms of height.
Edmontosaurus Specimens by Paleop on DeviantArt

For Past Meets Present (Must have an account to read):
Past Meets Present (Pt4 is Up) - The ZT2 Round Table

Original Model by DoctorSamWu (No Longer Available)
Edmontosaurus (Sam) | ZT2 Download Library Wiki | Fandom

Description
Edmontosaurus annectens

Hadrosaurids were a cornerstone of the Cretaceous period ecosystems across the northern hemisphere. They ranged in size from around 20 feet in length to as long as 40 feet, and possibly some species reaching more than 50 feet. By the end of the Cretaceous, American Hadrosaurs reached their apex in the form of a genus that goes by many names from Anatosaurus, Trachodon, Anatotitan, however, the most well-known binomial name being Edmontosaurus annectens.

History of Discovery:

It was discovered back in the 1882 by Dr. J. L. Wortman and R. S. Hill in South Dakota. They were on an expedition contracted E.D Cope of Philadelphia. At this time, he and his rival Othniel Marsh were locked in the infamous bone wars. The find consisted of a very well-preserved skull, and most of the animal was present except for sections of the torso. Cope sent it to the American Museum of Natural History and described as AMNH 5730. E.D. Cope described it as Dicolonius mirabilis. A species of Hadrosaur described by his mentor, Joseph Leidy. The generic name means "Double Sprout" from the Greek language, the species name, means marvelous. Today, it's still on display at the American Natural History Museum in New York City.

In 1892, while the Bone Wars was winding down, Marsh described a specimen of Hadrosaur called "Claosaurus annectens". He referred it to the genus he had discovered called Claosaurus, which was a basal Hadrosaur from Kansas. The genus name derived from "Clao" greek for Broken and Lizard because the type species C. agilis looking very fragmented when discovered. The specific name for this species "annectens" literally means "connected". Why he named the specimen this is unknown, as characteristic at this stage of the Bone Wars, Marsh sought to name as many species as he could to outrank his rival, Cope. The finds themselves consisted of a partial skull and fragmentary skeleton. A following specimen consisted of another complete skull. Today they are in the collection of the Yale Peabody Museum.

Edmontosaurus itself was named by Lawrence Lambe in 1917 when he discovered Edmontosaurus regalis in Canada. Edmontosaurus' name needs no explanation, "Edmonton's Lizard" as the formation, the Horsehoe Canyon formation was in the Edmonton group in Alberta.

The other species, E. annectens, had been—throughout the 1900s, it has been assigned to various and now outdated/dubious genera such as Anatotitan, Anatosaurus, Trachodon, and Claosaurus, to name a few. Various specimens assigned to various genera were either found to be dubious, invalid or not belonging to the genera.

Edmontosaurus annectens modern taxonomic position really started in the early to mid-1980s. It was called "Anatosaurus," literally meaning "Duck Lizard". However, Michael K. Brett-Surman researched this animal for his graduate studies. He found many similarities between Edmontosaurus and Anatosaurus, and they were subsumed into Edmontosaurus annectens, whereas the larger and more long-jawed Anatotitan copei warranted its own species.
In 2011, Canadian paleontologists David Evans and Nicolás Campione conducted studies on Anatotitan skulls and compared them to Edmontosaurus. They found that the increased length of the skulls in Anatotitan was due to ontogenetic changes as the animal matured. Thus, Anatotitan is now believed to have been a mature Edmontosaurus annectens.

Description:

The earliest known species was Edmontosaurus regalis. Ranging around 30-39 feet in length and living almost exclusively in what is today Canada, with a distinct fleshy comb-like structure on its head. Whether or not E. annectens had a fleshy comb is unknown. However, there were some differences between the two species. For one, the skull was more elongated in general compared to E. regalis. Especially as it reached older age (as will be discussed) and it was also more robustly built compared to any other American Hadrosaur.

Weighing in at around 7 tons on average, there are specimens that exceed that size with weights up to 11 or possibly 12 tons recorded in specimens like X-rex/MOR 1142. The animal was so massive, paleontologists thought it was a T.rex fossil, but we now know this animal belongs to a Edmontosaurus annectens. Along the back of the aforementioned specimen, it looks like there is evidence of distinctive half-moon shaped scales running down the back. Found on similar animals like Brachylophosaurus, it suggests that this feature may have been found across the entire family of Hadrosauridae.

These dinosaurs are often called "Duck-Billed Dinosaurs". The moniker is believed to have originating from Cope noting the skulls' wide muzzle and flattened tip at the end. However, Cope could not have known this as softer parts of the dinosaur had not survived fossilization with the specimens he and Marsh had found.

Given the size of these dinosaurs, they were mainly quadrupedal, but, could have been able to rear up and run on their hind legs if needed. The proper term is facultative bipeds, a form of locomotion exclusive to dinosaurs, with the only decent modern analogue being pangolins. However, the pangolins are far more quadrupedal than bipedal.

As previously mentioned, the skull was elongated in terms of length. However, as the dinosaur matured, it became both lower in terms of skull structure and far more elongated. This is something that is seen with a lot of saurolophines, such as Saurolophus itself. Namely the Mongolian species where an entire growth series has been pieced together, and E. annectens is no different. As mentioned in its history, largest and longest jawed specimens traditionally grouped as Anatotitan (meaning Giant Duck), are now believed to be E. annectens.
Classification:

E. annectens is a member of the Hadrosauridae family, classified in the saurolophini subfamily. This was a group of Hadrosaurs found across Asia and America. Famous members included Saurolophus itself and the giant Shantungosaurus. It's believed that this was the most derived member of the saurolophines by the end of the cretaceous next to the giant Shantungosaurus.

As previously mentioned, E. regalis was the first member of the genus to be classified. Given the complexity of taxonomy in this species, E. regalis is the type species. Some paleontologists have suggested to split up the genus with either Anatosaurus or Anatotitan. However, in all taxonomic studies in the intervening years, all have had E. annectens classified as a species of Edmontosaurus. There is a supposed third species that was at first classified as Ugrunaaluk kuukpikensis, named in 2015 and from Alaska's Prince Creek Formation. However, paleontologists noted this animal is indistinguishable from any other species of Edmontosaurus. Thus, it's generally believed to be either a northern occurrence of E. annectens or a late surviving E. regalis.

It's believed that E. regalis was the precursor to E. annectens. As the climate changed from the Campanian to Maastrichtian, the more diverse hadrosaurs being the lambeosaurini and parasaurolophini seem to vanish from the fossil record in more northern parts of North America. E. regalis would die out by 70,000,000 years ago. By the end of the Cretaceous, only Edmontosaurus annectens have be found in parts of the Northern states and Canada. Why this is the case is unknown, possibly because they were larger, these animals evolved convergently with T.rex or maybe they were just better adapted to this environment as they evolved into the last days of the dinosaurs.
Diet and Implied Feeding:

When Edmontosaurus was first discovered, it was thought that they ate soft water planets with their distinctive bill-like shape on, similar to their namesakes, ducks, and waterfowls. A very common trait of early paleoart with these animals being portrayed by famous paleoartists such as Rudolph Zallinger and Charles Knight as sluggish, semi-aquatic animals dipping their heads into the water to feed on water plants.

However, modern discoveries have painted a very different picture of how these animals ate.

Hadrosaurids, also known as "Duckbills," had distinctive snouts resembling bills of waterfowl. However, recent finds have challenged this view. First and foremost, they have teeth in their jaws, vastly different from ducks who use their beaks to strain the plant matter from their environment. They had massive batteries of teeth that show evidence of a chewing form of processing food.

John Ostrom, most famously known for discovering Deinonychus and noticing the bird-like connection between Dromaeosaurs and Archaeopteryx, prior to this, his masters was on the jaw morphology of various hadrosaurs. Most of the paleontological community knew these animals could chew. Ostrom however noticed something very different when he wrote his thesis in 1964. The teeth formed a distinctive grinding surface that, for a reptile could break down plant material in a method far more efficient than any other reptile. The animals efficiency in processing food was on par with some mammals. Moreover, the teeth showed more evidence of wear than Marsh and Cope had thought. They weren't straining food, they were eating very tough vegetation. This was the first inkling Ostrom had that these animals were probably more than sluggish animals.

Seemingly vindicating Ostrom, an extraordinary fossil paints an entirely different picture of this awesome animal. A specimen described in 1970, just when the Dinosaur Renaissance was starting to pick up momentum, shows these animals were anything but "duck-billed". A keratinous down-turned, hoe-like bill structure called a "rhamphotheca". It was likely designed to rake, clip, or strip the vegetation from its environment.
In terms of diet, recent analysis reveals that Edmontosaurus was a grazer of ferns and horsetail, but it also could have eaten from tougher vegetation like conifers. In general, it was probably a generalist in its environment. With its batteries of teeth, it made it a very efficient chewer of vegetation. Its jaws opening and closing in a clam-like fashion, masticating the material in its jaws.

No evidence of feathering or any filamentous structures have been found on these animals. However, the skin of these dinosaurs consisted entirely of scales. They were fine and small in a structure some have described as being akin to an "asphalt pavement" of sorts. More prominent scales were found up on the neck and parts of the leg as well.

Habitat and Social Behavior:

The most well-known environment Edmontosaurus was from is known as Hell Creek. Dating to around 68-66,000,000 years ago. Today, it is parts of Montana, North and South Dakota and Wyoming. The foothills of the Rockies and the badlands of the United States. When Edmontosaurus was around, the environment would have been nothing like it is today.

Hell Creek was a flood plain environment interspersed with conifer forests and fern prairies. Conifers such as Sequoia have been found in this environment. Cypress trees dominating the wetlands. There was also some more prevalent modern foliage around like oak, pine, and other hardwood trees. Flowering plants were abundant in this environment too. Edmontosaurus would have been found roaming the environment feeding upon the foliage in the region. The most prevalent environment attributed to Edmontosaurus that have been found would have been lowland swamps. The banks of these swamps would have been lined with cycad, tree ferns and horsetail. They would have used their prominent beak to clip plants from fronds from stems or branches.

Bonebeds from Hell Creek show multiple individuals found together. It's been suggested these were social dinosaurs dwelling in herds. Both this find and several other hadrosaurs have also been found fossilized together including Saurolophus from Mongolia, Maiasaura in Montana, Edmontosaurus regalis, its close cousin found in Canada, and finally Parasaurolophus, Lambeosaurus and Corythosaurus also found in a massive bonebed Canada. So, social behavior in these dinosaurs is not beyond belief.

Like the aforementioned Maiasaura, it's believed that these dinosaurs were reared in nesting colonies and probably had parents bring food to the hatchlings. While no nests attributable to Edmontosaurus have been found, its generally believed that Hadrosaurs had similar growth with juveniles having ungainly limbs and unable to leave the nest till they matured sufficiently.

Edmontosaurus was the second most common herbivore in the region. With 20% of the fossils recovered from Hell Creek being Edmontosaurus. Only Triceratops exceeds it in number with more than 40% of the fossils from Hell Creek being Triceratops. Alongside the three-horned face, smaller herbivores such as the agile Thescelosaurus, the ostrich-like Struthiomimus and thick-headed Pachycephalosaurus existed alongside it. Another titanic herbivore alongside Triceratops was the armored Ankylosaurus and smaller non-clubbed ankylosaur, Denversaurus.

Predators would have been the small Dromaeosaur, Acheroraptor perhaps preying on baby Edmontosaurus or their eggs if they can get to them in the nest. The larger predator, Dakotaraptor would have hunted babies or maybe juvenile Edmontosaurs right out of the nest. However, these two would have paled in comparison to the largest apex predator in North America, Tyrannosaurus rex. adolescent T. rex could have taken down juvenile animals and their titanic parents would have hunted Edmontosaurs of varying sizes. Their only defense would have been their tight social structure as well as probably their bulk. The evidence of Tyrannosaurus rex hunting Edmontosaurus is amazing (as will be discussed) as various fossils had both bite marks and scars have been found on their bones.

Fossils and Mummies:

Edmontosaurus has had a lot of well-preserved specimens unearthed over the years. Not just skulls and skeletons, but dinosaur mummies.

Where not just bones, skin, tissue, and occasionally even organs and keratinous structures survive across the eons, we've been able to get a much better view of what these titanic vegetarians looked like. In fact, the first Dinosaur mummy discovered was an Edmontosaurus annectens. Discovered in 1908 by paleontologist Charles Sternberg and his sons in the badlands of Wyoming. While it wasn't the best-preserved, it offered the first glance at what these great reptiles looked like.

Another find was LACM 23502, the mummy that preserved the keratinous beak. Contrary to Cope's view and the common moniker, the beak was not duck shaped, but had a keratinous rhamphotheca that formed a hooked shaped extension that also has implications in their diet and how they fed (as will be discussed). Unfortunately, while preparing the fossil, part of the rhamphotheca was chipped off as the preparator was not sure what the material was until half of it was knocked off.

However, perhaps the most complete was discovered in 1999 by then Student Tyler Lyson in North Dakota. It was nicknamed "Dakota" after its home state. He knocked off a piece of what he thought was just sandstone. Bringing it back to his home, he brushed the dust away and late at night, he realized: this was skin of a dinosaur. He knew it was a Hadrosaur as skin impressions have been found before, but nothing could compare to this. The skin had retained its 3D shape and hadn't collapsed in around the bone.
It's probably among the most complete of all Dinosaur Mummies. As far as studies go, not much has been published on this specimen, other than a couple of pictures of the animal; it may be years before seeing more information on this specimen.
However, pictures from the Mummy have given some newer views on this animal; among the most recent was that they had a hoof-like structure forming around the ground-contacting metacarpals. Digit 3 was the largest weight-bearing foot claw that contacted the ground. Digit 2 had a claw as well, digit 4 was probably just a thin pinky finger that was probably just vestigial and had no claw whatsoever.

As previously mentioned, T. rex dwelled alongside Edmontosaurus annectens. Fossil specimens of Edmontosaurus show bite marks and wounds inflicted by Tyrannosaurus rex. Scraping bite marks on the bones and healed up vertebra indicated that T.rex both fed upon and preyed upon Edmontosaurus. Specifically, DMHH 1943 which consists of a mature juvenile Edmontosaurus had a piece of tail vertebra bitten off. The injury on the vertebra healed. Meaning the Tyrannosaurus probably ambushed the dinosaur got a hold of the tail but was able to flee. A failed hunt on behalf of the Tyrannosaur.
Even more amazing was a study from 2013 conducted by David Burnham et al. that turned up an Edmontosaurus fossil with a Tyrannosaur tooth embedded in the bone. The injury healed around the bone and preserved it in the fossil.

Extinction:

Edmontosaurus vanished along with all non-avian dinosaurs at the end of the Cretaceous. When the infamous asteroid wiped all non-avian dinosaurs off the planet. The legacy this dinosaur would leave behind is one of taxonomic confusion, but also a small, but important footnote in terms of how paleontologists would eventually view dinosaurs as warm blooded active dinosaurs.

Furthermore, the discoveries of dinosaur mummies would show us that these animals were far more unique then at first glance. Not as swamp-dwelling, semi-aquatic giant ducks, but land-dwelling, tough-green chomping dinosaurs of Hell Creek.
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Okay, decided to re-write this profile as the old draft was driving me crazy.

This... actually was a lot easier to do then the first one. For one, the modifications to the back were a lot easier to do then I remember. Furthermore, I modified the hands a lot more adding the nail to the foot, making the hoof more prominent, and the nails and pinky, not as much. Of course, I added a growth series, but I thought I'd skip that here.

I decided to show juvenile T.rex harassing a group of Edmontosaurus and show the size of the adult Edmontosaurus. Yes, I could have gone for a T.rex ambush, but I wanted to emphasize the scale of these dinosaurs.

As previously said, this will be in Past Meets Present, and I've got some scenes planned out along with a T.rex. So, I look forward to that...

Also, as I also said, I'm still calling them Edmontosaurus and not Anatosaurus. And why Anatosaurus is making a comeback? IDK why. It really doesn't make any sense to me because, to be honest, the name of a dinosaur is completely subjective.

Data on how these animals ate was from Darren Naish's Blog:
Enough with the "Duck-Billed Dinosaurs" - Scientific American Blog Network

The length of these giants I took mainly from Paleop , and I made a rough approximation in terms of height.
Edmontosaurus Specimens by Paleop on DeviantArt

For Past Meets Present (Must have an account to read):
Past Meets Present (Pt4 is Up) - The ZT2 Round Table

Original Model by DoctorSamWu (No Longer Available)
Edmontosaurus (Sam) | ZT2 Download Library Wiki | Fandom