''Augustynolophus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of herbivorous

saurolophine Saurolophinae is a subfamily (biology), 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. How ...

hadrosaur Hadrosaurids (), also hadrosaurs 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 fami ...

dinosaur which was discovered in the

Moreno Formation The Moreno Formation is a Mesozoic geologic Formation (geology), 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 ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, dating to the late

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

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 Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

s known from the fossil record before the

Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event, also known as the K–T extinction, was the extinction event, mass extinction of three-quarters of the plant and animal species on Earth approximately 66 million years ago. The event cau ...

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," meaning crest, a reference to its relative ''

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 66 million ...

''. The specific name refers to palaeontologist William Morris. It was originally described as a species of ''Saurolophus'', ''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'' 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 Year#SI prefix multipliers, Ma), when the Western Interior Seaway split the continent of North America in two. In the Mesozoic era, Laramidia was an island ...

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

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

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

dentary In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone ...

and

predentary Ornithischia () is an extinct clade 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 Ancient ...

), 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 named dinosaurs from the western coast of the United States, the other two 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. Campa ...

'' Aletopelta coombsi,'' and 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, Kansa ...

.'' Additionally there are a number of fragmentary remains which have been found of dinosaurs in all of the western coastal states, California, Oregon, and Washington. In addition to a tyrannosaur from Sucia Island of Washington, fragmentary remains of indeterminate hadrosaurs and ornithopods have been found throughout California as far back as the 1930s and more recently Oregon as well. In September 2017, ''Augustynolophus'' was declared the official state dinosaur of

Description

Augustynolophus morrisi profile reconstruction

''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 geographic region located in the Appalachian Mountains#Regions, central and southern sections of the Appalachian Mountains in the east of North America. In the north, its boundaries stretch from the western Catskill Mountai ...

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, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...

. 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 (stratigraphy), formation s ...

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 82.4 Ma and 74.4 Ma, during Campanian (Late Cretaceous) time. It crops out to the east of the Rocky Mountai ...

. 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'' ("king turtle" in Greek) is a large, terrestrial Nanhsiungchelyidae, nanhsiungchelyid turtle from the Upper Cretaceous of North and Central America. ''Basilemys'' has been found in rocks dating to the Campanian and Maastrichtian subd ...

'' and '' Osteopygis''. 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 depos ...

'', '' Halisaurus'', '' Plesiotylosaurus'', and ''

Plotosaurus ''Plotosaurus'' ("swimmer lizard") is an extinct genus of large mosasaurs which lived during the Upper Cretaceous (Maastrichtian) in what is now North America. The taxon was initially described by University of California, Berkeley, Berkeley pale ...

''. Plesiosaurs that inhabited the Moreno Formation consisted of 4 genera: '' Frensosaurus'', '' Morenosaurus'', '' Aphrosaurus'', and ''Hydrotherosaurus''. ''

Bonnerichthys ''Bonnerichthys'' is a genus of fossil fishes within the family Pachycormidae that lived during the Coniacian to Maastrichtian stage of the Late Cretaceous. Fossil remains of this taxon were first described from the Smoky Hill Member of the N ...

'' and '' Saurodon'' were the only ray-finned fish found here. Indeterminate hadrosaur fossils are common in California too.

References

{{Taxonbar, from=Q17340197 Saurolophinae Dinosaur genera Maastrichtian dinosaurs Taxa named by Luis M. Chiappe Fossil taxa described in 2013 Fossil taxa described in 2014 Dinosaurs of the United States

History of discovery

Description

Paleoecology

See also

References