''Augustynolophus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of herbivorous

saurolophine Saurolophinae is a subfamily of hadrosaurid dinosaurs. It has since the mid-20th century generally been called the Hadrosaurinae, a group of largely non-crested hadrosaurs related to the crested sub-family Lambeosaurinae. However, the name Had ...

hadrosaur Hadrosaurids (), or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod family, which inclu ...

dinosaur which was discovered in the

Moreno Formation The Moreno Formation is a Mesozoic geologic formation located in San Joaquin Valley (California).Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.Weishampel, et al. (2004). "Dinosaur ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

, dating to the late

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interv ...

age, making it one of the last

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s known from the fossil record before the

Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden extinction event, mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million y ...

History of discovery

The generic name derives from a combination of the Augustyn family, who helped support the Los Angeles County Museum, and the suffix "-lophus," referring to its relation to ''Saurolophus''. The specific name refers to palaeontologist William Morris. It was originally described as a species of ''

Saurolophus ''Saurolophus'' (; meaning "lizard crest") is a genus of large hadrosaurid dinosaur from the Late Cretaceous period of Asia and North America, that lived in what is now the Horseshoe Canyon and Nemegt formations about 70 million to 68 millio ...

'', ''S. morrisi''. However, when a more in-depth study took place, the end results revealed that its cranial structure was vastly different when it was juxtaposed with the other known members of the tribe Saurolophini, most notably ''Saurolophus osborni'' and ''Saurolophus angustirostris'' and ''

Prosaurolophus maximus ''Prosaurolophus'' (; meaning "before ''Saurolophus''", in comparison to the later dinosaur with a similar head crest) is a genus of hadrosaurid (or duck-billed) dinosaur from the Late Cretaceous of North America. It is known from the remains of ...

'' and therefore, it was determined to be a separate genus. All known specimens of ''Augustynolophus'' have been found only in California, which was a part of

Laramidia Laramidia was an island continent that existed during the Late Cretaceous period (99.6–66 Ma), when the Western Interior Seaway split the continent of North America in two. In the Mesozoic era, Laramidia was an island land mass separated from ...

, among the best locations for dinosaur fossils. There are currently two known specimens of ''Augustynolophus''. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

, LACM/CIT 2852, was unearthed in 1943. It consisted of the majority of the skull (including the

dentary In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

and

predentary Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek s ...

), vertebrae, and bones of the limb and hand. The second specimen was designated LACM/CIT 2760. Discovered in 1939, it was made up of elements of the skull and limbs. Due to its smaller size, it may have been a juvenile. It is one of three known dinosaurs from western coast of the United States, the other three being the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

'' Aletopelta coombsi,'' the sea bird ''

Ichthyornis ''Ichthyornis'' (meaning "fish bird", after its fish-like vertebrae) is an extinct genus of toothy seabird-like ornithuran from the late Cretaceous period of North America. Its fossil remains are known from the chalks of Alberta, Alabama, Kan ...

'', and an undescribed species of

tyrannosaur Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent b ...

from

Washington state Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washingto ...

informally named '' Suciasaurus rex''. However, indeterminate hadrosaur and ornithopod remains have been found throughout California and similar areas as far back as the 1930s. In September 2017, ''Augustynolophus'' was declared the official state dinosaur of

Description

''Augustynolophus'' was a large hadrosaur, reaching in length and in body mass. Like all species of hadrosaur, ''Augustynolophus morrisi'' was a herbivorous dinosaur which had a diet consisting of the plant life in the area, it was specialized to chew its food since hadrosaurs were one of the few known species of dinosaur that chewed its food.

Paleoecology

Augustynolophus favcial and mandubular elements

Very is little is known about the fauna found in the coastal states of Laramida, which is a stark similarity to the neighboring island continent of

Appalachia Appalachia () is a cultural region in the Eastern United States that stretches from the Southern Tier of New York State to northern Alabama and Georgia. While the Appalachian Mountains stretch from Belle Isle in Newfoundland and Labrador, ...

which was on the opposite side of the

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, and the Western Interior Sea) was a large inland sea that split the continent of North America into two landmasses. The ancient se ...

. The western United States has a rich history of rich fossil finds, most notable examples include the

Hell Creek Formation The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation stretches over portions of ...

and the

Two Medicine Formation The Two Medicine Formation is a geological formation, or rock body, in northwestern Montana and southern Alberta that was deposited between and (million years ago), during Campanian (Late Cretaceous) time. It crops out to the east of the Rocky M ...

. However, like with Appalachia, the land fauna of western Laramidia, most notably the dinosaurs, is not well studied and are not well known. However, despite the fact that dinosaur fossils are rare in California, the

is one of the more well studied Mesozoic geological formations in California and like Appalachia, it is more well known for the large amount of marine fossils. ''Augustynolophus'' shared its environment with a wide variety of marine creatures which consisted of non-marine turtles, mosasaurs, plesiosaurs and ray-finned fish. The turtles that lived in this region included ''

Basilemys ''Basilemys'' () is a large, terrestrial trionychoid turtle from the Upper Cretaceous. In Greek, the word "Basil" means royal or kingly and the word "Emys" means turtle. Therefore, ''Basilemys'' means King Turtle. ''Basilemys'' has been found in r ...

'' and ''

Osteopygis ''Osteopygis'' is a genus of extinct turtle. ''Osteopygis'', as traditionally seen, is a chimera: the postcrania (including the holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when t ...

''. Mosasaurs were very common in this region and 4 species have been unearthed from this fossil formation. They include ''

Prognathodon ''Prognathodon'' is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Mosasaurinae subfamily, alongside genera like ''Mosasaurus'' and '' Clidastes''. ''Prognathodon'' has been recovered from dep ...

'', ''

Halisaurus ''Halisaurus'' is an extinct genus of marine reptile belonging to the mosasaur family. The holotype, consisting of an angular and a basicranium fragment discovered near Hornerstown, New Jersey, already revealed a relatively unique combination ...

'', ''

Plesiotylosaurus ''Plesiotylosaurus'', meaning "near ''Tylosaurus''", is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Mosasaurinae subfamily, alongside genera like ''Mosasaurus'' and ''Prognathodon''. The gen ...

'', and ''

Plotosaurus ''Plotosaurus'' ("swimmer lizard") is an extinct genus of mosasaur from the Upper Cretaceous (Maastrichtian) of Fresno County, California. Originally named ''Kolposaurus'' (meaning "bay lizard") by Berkeley paleontologist Charles Lewis Camp in 19 ...

''. Plesiosaurs that inhabited the Moreno Formation consisted of 4 genera: '' Frensosaurus'', ''

Morenosaurus ''Morenosaurus'' is an extinct genus of plesiosaur from the Cretaceous of what is now California. The type species is ''Morenosaurus stocki'', first named by Samuel Welles in 1943, in honor of Dr. Chester Stock.Hilton, Richard P., ''Dinosaur ...

'', ''

Aphrosaurus ''Aphrosaurus'' (meaning "sea-foam lizard") is an extinct genus of plesiosaur from the Late Cretaceous. The type species is ''Aphrosaurus furlongi'', named by Welles in 1943. ''Aphrosaurus furlongi'' was discovered in the Panoche Hills of Fres ...

'', and ''Hydrotherosaurus''. ''

Bonnerichthys ''Bonnerichthys'' is a genus of fossil fishes within the family Pachycormidae that lived during the Late Cretaceous Period Fossil remains of this taxon were first described from the Smoky Hill Member of the Niobrara Chalk Formation of Kansas ( ...

'' and ''

Saurodon ''Saurodon'' (from el, σαῦρος , 'lizard' and el, ὀδούς 'tooth') is an extinct genus of ichthyodectiform fish from the Cretaceous. ''Saurodon leanus'' is known to occur as early as the late Coniacian through the Santonian, in the ...

'' were the only ray-finned fish found here.

References

{{Taxonbar, from=Q17340197 Late Cretaceous dinosaurs of North America Saurolophines Fossil taxa described in 2014 Taxa named by Luis M. Chiappe Paleontology in California Symbols of California Ornithischian genera

History of discovery

Description

Paleoecology

See also

References