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Edmontosaurus

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Total anky death
Extinct as can be!
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Edmontosaurus
Temporal range: Late Cretaceous
CREST AWESOME
A restoration of Edmontosaurus regalis
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
clade: Dinosauria
Order: †Ornithischia
Suborder: †Ornithopoda
Family: †Hadrosauridae
Subfamily: †Saurolophinae
Tribe: †Edmontosaurini
Genus: †Edmontosaurus
Lambe, 1917
Type species
†Edmontosaurus regalis
Lambe, 1917
Referred species
  • †Edmontosaurus annectens (Marsh, 1892) †Edmontosaurus kuukipikensis? (Mori et al., 2015)
Synonyms
  • Anatosaurus Lull & Wright, 1942
  • Anatotitan Chapman & Brett-Surman, 1990

Edmontosaurus (Greek for "lizard from Edmonton") is an extinct genus of large Hadrosaur ornithopod from the Late Cretaceous of North America 73- 66 mya (Campanian to Maastrichtian). It contains the 2 known species: E. regalis and E. annectens. Fossils of E. regalis have been found in rocks of western North America that date from the Late Campanian stage of the Cretaceous Period 73 million years ago, while those of E. annectens were found in the same geographic region but in rocks dated to the end of the Maastrichtian stage of the Cretaceous, 66 million years ago.

Edmontosaurus was one of the largest Hadrosaur genera, being up to 9 m (30 ft) long and weighing about 4 tonnes (4.4 short tons). Evidence does exist in the form of two fossilized specimens in the Museum of the Rockies for an even greater maximum size of 17 m (49 ft) and weighing 10 metric tons (11 short tons) for Edmontosaurus annectens, however this estimate is dubious. A few well-preserved specimens are known that include not only bones, but in some cases extensive skin impressions and possible gut contents. It is classified as a genus of saurolophine (or hadrosaurine) hadrosaurid, a member of the group of hadrosaurids which lacked large, hollow crests, instead having smaller solid crests or fleshy combs.

The first fossils named Edmontosaurus were discovered in southern Alberta (named after Edmonton, the capital city), in the Horseshoe Canyon Formation (formerly called the lower Edmonton Formation). The type species, E. regalis, was named by Lawrence Lambe in 1917, although several other species that are now classified in Edmontosaurus were named earlier. The best known of these is E. annectens, named by Othniel Charles Marsh in 1892; originally as a species of Claosaurus, known for many years as a species of Trachodon, and later as Anatosaurus annectens. Anatosaurus, Anatotitan and Ugrunaaluk are now generally regarded as synonyms of Edmontosaurus. Ugrunnaluk is possibly a unique species of Edmontosaurus (E.kuukpikensis) however this species is regarded as Nomen dubium.

Edmontosaurus was widely distributed across western North America. The distribution of Edmontosaurus fossils suggests that it preferred coasts and coastal plains. It was a herbivore that could move on both two legs and four. Because it is known from several bone beds, Edmontosaurus is thought to have lived in groups, and may have been migratory as well. The wealth of fossils has allowed researchers to study its paleobiology in detail, including its brain, how it may have fed, and its injuries and pathologies, such as evidence for tyrannosaur attacks on a few edmontosaur specimens.

Discovery and history[]

Edmontosaurus has had a long and complicated history in paleontology, having spent decades with various species classified in other genera. Its taxonomic history intertwines at various points with the genera Agathaumas, Anatosaurus, Anatotitan, Claosaurus, Hadrosaurus, Thespesius, and Trachodon, and references predating the 1980s typically use Anatosaurus, Claosaurus, Thespesius, or Trachodon for edmontosaur fossils (excluding those assigned to E. regalis), depending on author and date. Although Edmontosaurus was only named in 1917, its oldest well-supported species (E. annectens) was named in 1892 as a species of Claosaurus.

Description[]

Edmontosaurus has been described in detail from numerous specimens. Like other hadrosaurids, it was a bulky animal with a long, laterally flattened tail and a head with an expanded, duck-like beak. The fore legs were not as heavily built as the hind legs, but were long enough to be used in standing or movement. Edmontosaurus was among the largest hadrosaurids: depending on the species, a fully grown adult could have been 9 metres (30 ft) long, and some of the larger specimens may have reached the range of 13 meters (43 ft) to 14 meters (47 ft) long but this is unlikely. Its weight was on the order of 7 metric tons (7.7 short tons). Traditionally, E. regalis has been regarded as the largest species, though this was challenged by the hypothesis that the larger hadrosaurid Anatotitan copei is a synonym of Edmontosaurus annectens, as put forward by Jack Horner and colleagues in 2004, and supported in studies by Campione and Evens in 2009 and 2011.

The type specimen of E. regalis, NMC 2288, is estimated as 9 to 12 metres (30 to 39 ft) long. E. annectens is often seen as smaller. Two mounted skeletons, USNM 2414 and YPM 2182, measure 8.00 metres (26.25 ft) long and 8.92 metres (29.3 ft) long, respectively. However, these are probably subadult individuals, and there is at least one report of a much larger potential E. annectens specimen, almost 13.5 metres (45ft) long. Two specimens still under study in the collection of the Museum of the Rockies - a 7.6 m (25 ft) tail labelled as MOR 1142 and another labelled as MOR 1609 - indicate that Edmontosaurus annectens could have grown to larger sizes, possibly rivaling Shantungosaurus in size. The specimens of these individuals indicate a length of up to 17 m (57 ft), according to paleontologists, in 2022, these estimates were disproved. If individuals of Edmontosaurus really did grow to be this big, it is likely that they would have been very rare due to such factors as environmental stress, disease, and predation.

Classification[]

Edmontosaurus was a hadrosaurid (a duck-billed dinosaur), a member of a family of dinosaurs which to date are known only from the Late Cretaceous. It is classified within the Saurolophinae (alternately Hadrosaurinae), a clade of hadrosaurids which lacked hollow crests. Other members of the group include Brachylophosaurus, Gryposaurus, Lophorhothon, Maiasaura, Naashoibitosaurus, Prosaurolophus, and Saurolophus. It was either closely related to or includes the species Anatosaurus annectens (alternately Edmontosaurus annectens), a large hadrosaurid from various latest Cretaceous formations of western North America. The giant Chinese hadrosaurine Shantungosaurus giganteus is also anatomically similar to Edmontosaurus; M. K. Brett-Surman found the two to differ only in details related to the greater size of Shantungosaurus, based on what had been described of the latter genus.

While the status of Edmontosaurus as a saurolophine has not been challenged, its exact placement within the clade is uncertain. Early phylogenies, such as that presented in R. S. Lull and Nelda Wright's influential 1942 monograph, had Edmontosaurus and various species of Anatosaurus (most of which would be later considered as additional species or specimens of Edmontosaurus) as one lineage among several lineages of "flat-headed" hadrosaurs. One of the first analyses using cladistic methods found it to be linked with Anatosaurus (=Anatotitan) and Shantungosaurus in an informal "edmontosaur" clade, which was paired with the spike-crested "saurolophs" and more distantly related to the "brachylophosaurs" and arch-snouted "gryposaurs". A 2007 study by Terry Gates and Scott Sampson found broadly similar results, in that Edmontosaurus remained close to Saurolophus and Prosaurolophus and distant from Gryposaurus, Brachylophosaurus, and Maiasaura. However, the most recent review of Hadrosauridae, by Jack Horner and colleagues (2004), came to a noticeably different result: Edmontosaurus was nested between Gryposaurus and the "brachylophosaurs", and distant from Saurolophus.

Paleobiology[]

In a 2011 study, Campione and Evans recorded data from all known "edmontosaur" skulls from the Campanian and Maastrichtian and used it to plot a morphometric graph, comparing variable features of the skull with skull size. Their results showed that within both recognized Edmontosaurus species, many features previously used to classify additional species or genera were directly correlated with skull size. Campione and Evans interpreted these results as strongly suggesting that the shape of Edmontosaurus skulls changed dramatically as they grew. This has led to several apparent mistakes in classification in the past. The Campanian species Thespesius edmontoni, previously considered a synonym of E. annectens due to its small size and skull shape, is more likely a subadult specimen of the contemporary E. regalis.

Similarly, the three previously recognized Maastrichtian edmontosaur species likely represent growth stages of a single species, with E. saskatchewanensis representing juveniles, E. annectens subadults, and Anatotitan copei fully mature adults. The skulls became longer and flatter as the animals grew.

Paleoecology[]

Edmontosaurus was a wide-ranging genus in both time and space. The rock units from which it is known can be divided into two groups by age: the older Horseshoe Canyon and St. Mary River formations, and the younger Frenchman, Hell Creek, and Lance formations. The time span covered by the Horseshoe Canyon Formation and equivalents is also known as Edmontonian, and the time span covered by the younger units is also known as Lancian. The Edmontonian and Lancian time intervals had distinct dinosaur faunas.

The Edmontonian land vertebrate age is defined by the first appearance of Edmontosaurus regalis in the fossil record. Although sometimes reported as of exclusively early Maastrichtian age, the Horseshoe Canyon Formation was of somewhat longer duration. Deposition began approximately 73 million years ago, in the late Campanian, and ended between 68.0 and 67.6 million years ago. Edmontosaurus regalis is known from the lowest of five units within the Horseshoe Canyon Formation, but is absent from at least the second to the top. As many as three quarters of the dinosaur specimens from badlands near Drumheller, Alberta may pertain to Edmontosaurus.

In popular culture[]

  • A hadrosaur skull can be seen among the pile of bones in the Tyrannosaurus rex nest in The Lost World: Jurassic Park. Jurassic Park Legacy members long concluded that it belonged to the genus Anatotitan, which is now classified as Edmontosaurus annectens. It is unknown if Edmontosaurus was on Isla Sorna or was even recreated by InGen before Jurassic World in the Movie canon.
    • According to the computer game, Tresspasser, Hammond's memoir confirm that in the early progress of Jurassic Park half of the 13 species that originally were bred for the Park failed to adjust to their new ecosystem on, Isla Sorna (Site-B) and once more went extinct.
      • Because Tresspasser serves as canonical continuity to the film The Lost World: Jurassic Park, this would confirm that among the 13 original species, the Edmontosaurus was indeed one of them. The cause of its re-extinction is uncertain, but a suggestion is that due to stress of the new environment, new plant sources and the increase in predator population, this is what likely caused its extinction before the events of the film series.
  • Edmontosaurus made an appearence in the 3rd episode of Planet Dinosaur where a herd was attack by a species of Alaskan Troodon.
  • Edmontosaurus appeared in March of the Dinosaurs, where it follows a juvenile Edmontosaurus called Scar, trying to find the herd after being lost after a pack of Albertosaurus attacked.
  • Edmontosaurus was one of the dinosaurs confirmed to be in Jurassic World: Evolution, according to the second in-game trailer. It looks almost exactly as the Jurassic World website version, with one difference in the game version, as it has a yellow fleshly crest on its head like in life, although more exaggerated than in life. Oddly enough the developers, Frontier for some replaced the film's Edmontosaurus annectens, which is what the website version seems to be based on instead, with the species, Edmontosaurus regalis.
    • This was change was likely to avoid any confusion the nomenclature controversy between the two species, as of today paleontologists still debate whether the referred original species is either its own genus or another species of Edmontosaurus itself, as it was namely given upon its discovery.
  • Edmontosaurus appeared in 2 Jurassic Park video games, The Lost World: Jurassic Park Arcade Game & Jurassic Park: Operation Genesis.
  • Edmontosaurus was seen in The Ultimate Guide: T-Rex and briefly as a carcass in Beyond T-Rex.
  • It was seen at through the PBS Nova Documentary Arctic Dinosaurs.
  • It appears on the Jurassic World website and is stated to be in the park, but it is unfortunately never seen in the film. Edmontosaurus also fell back into extinction after the Isla Nublar Incident of 2015. But a skeleton of Edmontosaurus is seen in the Lockwood Manor in Jurassic World: Fallen Kingdom.
  • It will appear in Saurian under its' old name Anatosaurus.
  • Edmontosaurus appeared in the ROBLOX game "Era of Terror" before the game was taken down for unknown reasons. It does not appear in the remake.
  • Edmontosaurus appeared as both E. kuukpikensis, E. regalis & E. annectens in the 2022-2023 BBC Documentary Series, Prehistoric Planet.
  • Edmontosaurus recently appeared in the new Netflix Original Documentary Series, Life on Our Planet.
  • Edmontosaurus appears in Prehistoric Kingdom with skins for E.regalis, E.annectens, and E.kuukipikensis.

References[]

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