''Prosaurolophus'' (; meaning "before ''

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 million ...

''", in comparison to the later dinosaur with a similar head crest) is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 includ ...

id (or duck-billed)

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 ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. It is known from the remains of at least 25 individuals belonging to two species, including skulls and skeletons, but it remains obscure. Its fossils have been found in the

late 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. Campanian ...

-age

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

Dinosaur Park Formation The Dinosaur Park Formation is the uppermost member of the Belly River Group (also known as the Judith River Group), a major geologic unit in southern Alberta. It was deposited during the Campanian stage of the Late Cretaceous, between about 76. ...

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

, and the roughly contemporaneous

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 ...

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

, dating to around 75.5-74.0 million years ago. Its most recognizable feature is a small solid crest formed by the

nasal bone The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Eac ...

s, sticking up in front of the eyes. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''P. maximus'', described by American paleontologist

Barnum Brown Barnum Brown (February 12, 1873 – February 5, 1963), commonly referred to as Mr. Bones, was an American paleontologist. Named after the circus showman P. T. Barnum, he discovered the first documented remains of ''Tyrannosaurus'' during a career ...

of the

American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...

in 1916. A second species, ''P. blackfeetensis'', was described by Jack Horner of the

Museum of the Rockies Museum of the Rockies is a museum in Bozeman, Montana. Originally affiliated with Montana State University in Bozeman, and now also, the Smithsonian Institution, the museum is largely known for its paleontological collections. The Museum houses ...

in 1992. The two species were differentiated mainly by crest size and skull proportions.

Description

''Prosaurolophus'' was a large-headed duckbill; the most complete described specimen has a skull around long with its body size measuring in length and in body mass. It had a small, stout, triangular crest in front of the eyes; the sides of this crest were concave, forming depressions. This crest grew isometrically (i.e. without changing in proportion) throughout the lifetime of the individual, leading to speculation that the species may have had a soft tissue display structure, such inflatable nasal sacs. When originally described by Brown, ''Prosaurolophus maximus'' was known from a skull and jaw. Half of the skull was badly weathered at the time of examination, and the level of the parietal was distortedly crushed upwards to the side. The different bones of the skull could be easily defined, with the exception of the parietals and

s. Brown found that the skull of the already described genus ''Saurolophus'' is very similar overall to, but also smaller than the skull of ''P. maximus''. The unique feature of a shortened frontal in lambeosaurines is also found in ''Prosaurolophus'', and the other horned hadrosaurines ''

Brachylophosaurus ''Brachylophosaurus'' ( or ; meaning "short-crested lizard", Greek ''brachys'' = short + ''lophos'' = crest + ''sauros'' = lizard, referring to its small crest) was a mid-sized member of the hadrosaurid family of dinosaurs. It is known from sev ...

'', ''

Maiasaura ''Maiasaura'' (from the Greek ''μαῖα'', meaning "good mother" and ''σαύρα'', the feminine form of ''saurus'', meaning "reptile") is a large herbivorous saurolophine hadrosaurid ("duck-billed") dinosaur genus that lived in the area curre ...

'', and ''

''. Although they lack a shorter frontal, the genera ''

Edmontosaurus ''Edmontosaurus'' ( ) (meaning "lizard from Edmonton") is a genus of hadrosaurid (duck-billed) dinosaur. It contains two known species: ''Edmontosaurus regalis'' and ''Edmontosaurus annectens''. Fossils of ''E. regalis'' have been found in rocks ...

'' and ''

Shantungosaurus ''Shantungosaurus'' (meaning "''Shandong Lizard''") is a genus of very large saurolophine hadrosaurid dinosaur found in the Late Cretaceous Wangshi Group of the Shandong Peninsula in China, containing a single species, ''Shantungosaurus giganteu ...

'' share with saurolophins an elongated

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 tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...

Patches of preserved skin are known from two juvenile specimens,

TMP TMP can refer to any of the following: Chemistry * 2,2,6,6-Tetramethylpiperidine, an organic chemistry reagent * Thymidine monophosphate, a nucleotide * Trimethoprim, an antibiotic * Trimethyl phosphate, a solvent * Trimethylolpropane, a precurso ...

1998.50.1 and TMP 2016.37.1; these pertain to the ventral extremity of the ninth through fourteenth dorsal ribs, the caudal margin of the scapular blade, and the pelvic region. Small basement scales (scales which makeup the majority of the skin surface), in diameter, are preserved on these patches - this is similar to the condition seen in other saurolophine hadrosaurs. More uniquely, feature scales (larger, less numerous scales which are interspersed within the basement scales) around wide and long are found interspersed in the smaller scales in the patches from the ribs and scapula (they are absent from the pelvic patches). Similar scales are known from the tail of the related '' Saurolophus angustirostris'' (on which they have been speculated to indicate pattern), and it is considered likely adult ''Prosaurolophus'' would've retained the feature scales on their flanks like the juveniles.

History of discovery

Well-known

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Barnum Brown recovered a duckbill skull in 1915 for the

(AMNH 5836) from the

Red Deer River The Red Deer River is a river in Alberta and a small portion of Saskatchewan, Canada. It is a major tributary of the South Saskatchewan River and is part of the larger Saskatchewan-Nelson system that empties into Hudson Bay. Red Deer River ...

of Alberta, near Steveville. He described the specimen in 1916 as a new genus, ''Prosaurolophus''. Brown's choice of name comes from a comparison to the genus ''Saurolophus'', which he had described in 1912. ''Saurolophus'' had a similar but longer and more spike-like head crest. The skull had a damaged muzzle and was inadvertently reconstructed too long, but better remains were soon found that showed the true shape; one is a nearly complete skeleton and skull, described by William Parks in 1924. Twenty to twenty-five individuals are known for this species, including seven skulls with at least some of the rest of the skeleton. The second species, ''P. blackfeetensis'', is based on a specimen in the Museum of the Rockies (MOR 454), which was described by another notable paleontologist, Jack Horner. This specimen, and the remains of three or four other individuals, were found in Glacier County, Montana. In this case, the fossils were found in a

bonebed A bone bed is any geological stratum or deposit that contains bones of whatever kind. Inevitably, such deposits are sedimentary in nature. Not a formal term, it tends to be used more to describe especially dense collections such as Lagerstätt ...

of ''Prosaurolophus'' remains, which indicates that the animals lived together for at least some time. The bonebed is interpreted as reflecting a group of animals that congregated near a water source during a drought. Horner differentiated the two species by details of the crest. He interpreted ''P. blackfeetensis'' as having a steeper, taller face than ''P. maximus'', with the crest migrating backward toward the eyes during growth. More recent studies have regarded the differences as insufficient to support two species.

Classification

Because of its name, ''Prosaurolophus'' is often associated with ''Saurolophus''. However, this is contentious; some authors have found the animals to be closely related, whereas others have not, instead finding it closer to ''Brachylophosaurus'', ''Edmontosaurus'', ''

Gryposaurus ''Gryposaurus'' (meaning "hooked-nosed (Ancient Greek, Greek ''grypos'') lizard"; sometimes incorrectly translated as "griffin (Latin ''gryphus'') lizard") was a genus of hadrosaur, duckbilled dinosaur that lived about 80 to 75 million years ...

'', and ''Maiasaura''.

History of classification

In 1918,

Lawrence Lambe Lawrence Morris Lambe (August 27, 1863 – March 12, 1919) was a Canadian geologist, palaeontologist, and ecologist from the Geological Survey of Canada (GSC). His published work, describing the diverse and plentiful dinosaur discoveries from th ...

revised the classifications of Hadrosauridae (then Trachodontidae). He invalidated the family name and Trachodontinae, replacing them with Hadrosauridae and Hadrosaurinae. The other subfamily in Hadrosauridae then was Saurolophinae, which included '' Stephanosaurus'' (= ''

Lambeosaurus ''Lambeosaurus'' ( , meaning " Lambe's lizard") is a genus of hadrosaurid dinosaur that lived about 75 million years ago, in the Late Cretaceous period (Campanian stage) of North America. This bipedal/quadrupedal, herbivorous dinosaur is k ...

''), '' Cheneosaurus'', ''

Corythosaurus ''Corythosaurus'' (; ) is a genus of hadrosaurid "duck-billed" dinosaur from the Upper Cretaceous Period (geology), Period, about 77–75.7 million years ago. It lived in what is now North America. Its name means "helmet lizard", derived fr ...

'', ''Prosaurolophus'', and ''Saurolophus''. Lambe, in 1920, split Saurolophinae and found only two genera remaining in it, ''Prosaurolophus'', and the type genus. The previous genera were then reclassified into Stephanosaurinae or Hadrosaurinae. In 1928, ''Prosaurolophus'' was assigned to

Saurolophinae 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 Hadro ...

Franz Nopcsa Franz may refer to: People * Franz (given name) * Franz (surname) Places * Franz (crater), a lunar crater * Franz, Ontario, a railway junction and unorganized town in Canada * Franz Lake, in the state of Washington, United States – see ...

. The group contained hadrosaurids with a "males with median horn-like protuberance on the skull" and "very numerous teeth", found by Nopsca to be ''

Parasaurolophus ''Parasaurolophus'' (; meaning "near crested lizard" in reference to '' Saurolophus)'' is a genus of herbivorous hadrosaurid ornithopod dinosaur that lived in what is now North America and possibly Asia during the Late Cretaceous Period, abou ...

'', ''Saurolophus'', and ''Prosaurolophus''. In 1954, Charles Sternberg reevaluated the genera in Hadrosauridae, invoking the probability that Saurolophinae should be sunk into Hadrosaurinae. This greatly changed the classifications of the family, as the "saurolophines" were kept separate because of their supposedly "footed"

ischium The ischium () form ...

. Sternberg identified that the "footed" ischium assigned to ''Saurolophus'' was not found with the holotype, and was only assigned to it because of the location of the find. Also, he noted that William Parks (1924) found a complete skeleton of ''Prosaurolophus'' clearly showing an "unfooted" ischium, which Sternberg realized meant that it was unlikely that ''Saurolophus'' possessed a "footed" ischium. Sternberg's reevaluation led to the abandonment of Saurolophinae. Young (1958) found that the subfamily Saurolophinae, however, was not to be abandoned, and in it placed his new genus ''

Tsintaosaurus ''Tsintaosaurus'' (; meaning "Qingdao lizard", after the old transliteration "Tsingtao") is a genus of hadrosaurid dinosaur from China. It was about long and weighed . The type species is ''Tsintaosaurus spinorhinus'', first described by Chine ...

'', as well as ''Prosaurolophus'' and ''Saurolophus'', and also ''Kritosaurus'' (which included ''Gryposaurus'' and excluded ''K. navajovius''). Two years previous,

Friedrich von Huene Friedrich von Huene, born Friedrich Richard von Hoinigen, (March 22, 1875 – April 4, 1969) was a German paleontologist who renamed more dinosaurs in the early 20th century than anyone else in Europe. He also made key contributions about v ...

separated Saurolophinae from Hadrosauridae, naming Saurolophidae. Saurolophidae was a family in Huene's Hadrosauria, including the genera ''Prosaurolophus'', ''Saurolophus'', and the probably unrelated ''

Bactrosaurus ''Bactrosaurus'' (; meaning "Club lizard," "baktron" = club + ''sauros'' = lizard) is a genus of herbivorous hadrosauroid dinosaur that lived in Asia during the Late Cretaceous, about 96-85 million years ago. The position ''Bactrosaurus'' occupi ...

''. Another author to support the separation of Saurolophinae was

John Ostrom John Harold Ostrom (February 18, 1928 – July 16, 2005) was an American paleontologist who revolutionized modern understanding of dinosaurs in the 1960s. As first proposed by Thomas Henry Huxley in the 1860s, Ostrom showed that dinosaurs were ...

(1961). Ostrom found that the saurolophines ''Brachylophosaurus'', ''Prosaurolophus'', and ''Saurolophus'' all possessed a "pseudonarial crest", a feature which united them, while distinguishing them from hollow-crested lambeosaurines. Hopson (1975) supported the division of Hadrosauridae into two subfamilies, Hadrosaurinae and Lambeosaurinae, and was first to suspect what modern analyses find. Hopson found that Hadrosaurinae could clearly be divided into groups, the "kritosaurs", the "edmontosaurs", and the "saurolophines", including ''Prosaurolophus'', ''Saurolophus'', ''Tsintaosaurus'' and ''

Lophorhothon ''Lophorhothon'' is a genus of hadrosauroid dinosaur from the Late Cretaceous, the first genus of dinosaur discovered in Alabama, in the United States. Discovery and naming Remains of this small, poorly known perhaps saurolophine dinosaur ...

'', and intermediate between the "kritosaurs" and "saurolophines". Brett-Surman (1975) also followed Sternberg with sinking Saurolophinae into Hadrosaurinae, and like Hopson, he recognized three groups within the subfamily. Like Hopson, one group was called the ''Edmontosaurus'' lineage, the second the ''Kritosaurus'' group, and the third uniting ''Prosaurolophus'' and ''Saurolophus''. Over a decade later in 1989, Brett-Surman scientifically named the groups of hadrosaurines, the first becoming

Edmontosaurini Edmontosaurini are a tribe of saurolophine hadrosaur dinosaurs that lived in the Northern Hemisphere during the Late Cretaceous period. It currently contains '' Edmontosaurus'' (from Canada and the United States), '' Shantungosaurus'' and '' La ...

, the second

Kritosaurini Kritosaurini is a tribe of saurolophine hadrosaurid dinosaurs from the Late Cretaceous. Discovery and naming The first member of the group discovered and named was ''Kritosaurus''; it was named by paleontologist Barnum Brown in 1910. Four year ...

, and the third

Saurolophini Saurolophini is a tribe of saurolophine hadrosaurids native to the Americas and Asia. It includes '' Saurolophus'' (from Canada and Mongolia), '' Augustynolophus'' (from the United States), and ''Prosaurolophus'' (from Alberta, Canada, and Mont ...

Phylogeny

The first cladistic analysis to encompass the interrelationships of Hadrosauridae was conducted by Weishampel and Horner (1990). They found Saurolophinae synonymous with Hadrosaurinae, but only separated the subfamily into two groups. The first group included ''Gryposaurus'', ''

Aralosaurus ''Aralosaurus'' was a genus of hadrosaurid dinosaur that lived during the Late Cretaceous in what is now Kazakhstan. It is known only by a posterior half of a skull (devoid of its mandible) and some post-cranial bones found in the Bostobe Formati ...

'', ''Maiasaura'', and ''Brachylophosaurus''. The other contained ''Edmontosaurus'', ''Saurolophus'', ''Prosaurolophus'', ''Lophorhothon'', and ''Shantungosaurus''. A detailed cladgram of hadrosaurid relationships was published in 2013 by

Acta Palaeontologica Polonica ''Acta Palaeontologica Polonica'' is a quarterly peer-reviewed open access scientific journal of paleontology and paleobiology. It was established by Roman Kozłowski in 1956. It is published by the Institute of Paleobiology of the Polish Academy ...

. The study was led by Alberto Prieto-Márquez, and recovered ''Prosaurolophus'' in a similar position as suggested by Brown in 1916. The below cladogram was the one recovered by their analysis: Prosaurolophus maximus1

In 2001, ''Prosaurolophus'' was studied with other hadrosaurids by Wagner. The genus, along with ''Corythosaurus'' and ''Maiasaura'', were considered by Wagner to be synonymous with ''Saurolophus'', ''Hypacrosaurus'' and ''Brachylophosaurus'' respectively. ''Prosaurolophus maximus'' was reassigned to ''Saurolophus'' as ''S. maximus''. The same year however, ''Prosaurolophus'' was found to be distinct from ''Saurolophus'', in an analysis of Hu ''et al.''. Their analysis was unique from any of the time, and they recovered ''Prosaurolophus'' in Saurolophinae, with ''Saurolophus'', ''Lophorhothon'', ''Tsintaosaurus'', ''

Jaxartosaurus ''Jaxartosaurus'' (meaning "Jaxartes lizard" after the early name of the Syr Darya) is a genus of hadrosaurid dinosaur similar to ''Corythosaurus'' which lived during the Late Cretaceous. Its fossils were found in Kazakhstan. Description ''Jaxar ...

'', and ''Kritosaurus''. No other analysis has recovered this group of dinosaurs. Horner ''et al.'' (2004) also recovered a different phylogeny of Saurolophinae. ''Prosaurolophus'' was, for the first time, recovered separate from ''Saurolophus'', in fact not even closely related. ''Prosaurolophus'' was found in a group with ''Brachylophosaurus'', ''Maiasaura'', ''Grpyosaurus'', and ''Edmontosaurus'', while ''Saurolophus'' was grouped with ''

Naashoibitosaurus ''Naashoibitosaurus'' (from Navajo language, Navajo —"creek lizard") is a genus of hadrosaurid dinosaur that lived about 73 million years ago, in the Late Cretaceous, and was found in the Kirtland Formation of the San Juan, New Mexico, San ...

'' (=''Kritosaurus'') and "Kritosaurus" ''australis''. The ''Prosaurolophus''-''Saurolophus'' clade has been a problematic grouping when trying to place among hadrosaurines. Many skull features are similar to ''Edmontosaurus'', while other are closer to ''Gryposaurus'', so the group has been classified as close to both. However, the clade might be closer to ''Edmontosaurus'', as the features are more numerous uniting them.

Paleobiology

As a hadrosaurid, ''Prosaurolophus'' would have been a large

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

, eating

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

s with a sophisticated skull that permitted a grinding motion analogous to

chewing Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, th ...

. Its

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

were continually replaced and packed into

dental batteries Dinosaur teeth have been studied since 1822 when Mary Ann Mantell (1795-1869) and her husband Dr Gideon Algernon Mantell (1790-1852) discovered an ''Iguanodon'' tooth in Sussex in England. Unlike mammal teeth, individual dinosaur teeth are gener ...

that contained hundreds of teeth, only a relative handful of which were in use at any time. Plant material would have been cropped by its broad beak, and held in the jaws by a

cheek The cheeks ( la, buccae) constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the inside ...

-like structure. Feeding would have been from the ground up to around 4 meters (13 ft) above. Like other hadrosaurs, it could have moved both

bipedally Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' 'double' a ...

and

quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...

ally. Comparisons between the scleral rings of ''Prosaurolophus'' and modern birds and reptiles suggest that it may have been

cathemeral Cathemerality, sometimes called metaturnality, is an organismal activity pattern of irregular intervals during the day or night in which food is acquired, socializing with other organisms occurs, and any other activities necessary for livelihood ar ...

, active throughout the day at short intervals.

Social behavior

As noted, there is bonebed evidence that this genus lived in groups during at least part of the year. Additionally, it had several potential methods for display in a social setting. The bony facial crest is an obvious candidate, and nasal diverticula may also have been present. These postulated

diverticula In medicine or biology, a diverticulum is an outpouching of a hollow (or a fluid-filled) structure in the body. Depending upon which layers of the structure are involved, diverticula are described as being either true or false. In medicine, t ...

would have taken the form of inflatable soft-tissue sacs housed in the deep excavations flanking the crest and elongate holes for the

nostril A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...

s. Such sacs could be used for both visual and auditory signals.

Paleoecology

The Dinosaur Park Formation, home to ''Prosaurolophus maximus'', is interpreted as a low-relief setting of

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

s and

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

s that became more

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

y and influenced by

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

conditions over time as 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 sea, ...

transgressed westward.Eberth, David A. 2005. "The geology", in ''Dinosaur Provincial Park'', pp. 54–82. The climate was warmer than present-day Alberta, without

frost Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a gas) ...

, but with wetter and drier seasons.

Conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...

s were apparently the dominant

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...

plants, with an

understory In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abov ...

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

tree fern The tree ferns are arborescent (tree-like) ferns that grow with a trunk elevating the fronds above ground level, making them trees. Many extant tree ferns are members of the order Cyatheales, to which belong the families Cyatheaceae (scaly tree ...

s, and

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s.Braman, Dennis R., and Koppelhus, Eva B. 2005. "Campanian palynomorphs", in ''Dinosaur Provincial Park'', pp. 101–130. In this well-studied formation, ''P. maximus'' is only known from the upper part, which had more of a marine influence than the lower section. It was the most common hadrosaurine of this section, which was deposited about 75.5 million years ago. The Dinosaur Park Formation was also home to well-known dinosaurs like the

horned A horn is a permanent pointed projection on the head of various animals that consists of a covering of keratin and other proteins surrounding a core of live bone. Horns are distinct from antlers, which are not permanent. In mammals, true horns ...

Centrosaurus ''Centrosaurus'' ( ; ) is a genus of herbivorous ceratopsian dinosaur from the Late Cretaceous of Canada. Their remains have been found in the Dinosaur Park Formation, dating from 76.5 to 75.5 million years ago. Discovery and naming The firs ...

'', ''

Styracosaurus ''Styracosaurus'' ( ; meaning "spiked lizard" from the Ancient Greek / "spike at the butt-end of a spear-shaft" and / "lizard") is a genus of herbivorous ceratopsian dinosaur from the Cretaceous Period (Campanian stage), about 75.5 to 74.5&nbs ...

'', and ''

Chasmosaurus ''Chasmosaurus'' ( ) is a genus of ceratopsid dinosaur from the Upper Cretaceous Period of North America. Its name means 'opening lizard', referring to the large openings ( fenestrae) in its frill (Greek ''chasma'' meaning 'opening' or 'hollow' ...

'', fellow duckbills ''Gryposaurus'', ''Corythosaurus'', ''Lambeosaurus'', and ''Parasaurolophus'',

tyrannosaurid Tyrannosauridae (or tyrannosaurids, meaning "tyrant lizards") is a family of coelurosaurian theropod dinosaurs that comprises two subfamilies containing up to thirteen genera, including the eponymous ''Tyrannosaurus''. The exact number of genera ...

Gorgosaurus ''Gorgosaurus'' ( ; ) is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period (Campanian), between about 76.6 and 75.1 million years ago. Fossil remains have been found in the Can ...

'', and

armored Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or f ...

Edmontonia ''Edmontonia'' is a genus of panoplosaurin nodosaurid dinosaur from the Late Cretaceous Period. It is part of the Nodosauridae, a family within Ankylosauria. It is named after the Edmonton Formation (now the Horseshoe Canyon Formation in Canada) ...

'' and ''

Euoplocephalus ''Euoplocephalus'' ( ) is a genus of very large, herbivorous ankylosaurid dinosaurs, living during the Late Cretaceous of Canada. It has only one named species, ''Euoplocephalus tutus''. The first fossil of ''Euoplocephalus'' was found in 1897 i ...

''.Weishampel, David B.; Barrett, Paul M.; Coria, Rodolfo A.; Le Loeuff, Jean; Xu Xing; Zhao Xijin; Sahni, Ashok; Gomani, Elizabeth, M.P.; and Noto, Christopher R. (2004). "Dinosaur Distribution", in ''The Dinosauria'' (2nd), pp. 517–606. The roughly contemporaneous Two Medicine Formation, home to ''P. maximus'', is well known for its fossils of dinosaur nests, eggs, and young, produced by the hadrosaurids '' Hypacrosaurus stebingeri'' and ''Maiasaura'', and the

troodontid Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discov ...

Troodon ''Troodon'' ( ; ''Troödon'' in older sources) is a wastebasket taxon and a dubious genus of relatively small, bird-like dinosaurs known definitively from the Campanian age of the Late Cretaceous period (about 77 mya). It includes at least ...

''. The tyrannosaurid ''

Daspletosaurus ''Daspletosaurus'' ( ; meaning "frightful lizard") is a genus of tyrannosaurid dinosaur that lived in Laramidia between about 79.5 and 74 million years ago, during the Late Cretaceous Period. The genus ''Daspletosaurus'' contains three species ...

'', caenagnathid ''

Chirostenotes ''Chirostenotes'' ( ; named from Greek 'narrow-handed') is a genus of oviraptorosaurian dinosaur from the late Cretaceous (about 76.5 million years ago) of Alberta, Canada. The type species is ''Chirostenotes pergracilis''. History of discovery ...

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dromaeosaurids Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...

'' Bambiraptor'' and ''

Saurornitholestes ''Saurornitholestes'' ("lizard-bird thief") is a genus of carnivorous dromaeosaurid theropod dinosaur from the late Cretaceous of Canada (Alberta) and the United States (Montana, New Mexico, Alabama, North Carolina, and South Carolina). Two spec ...

'', armored dinosaurs ''Edmontonia'' and ''Euoplocephalus'',

hypsilophodont Hypsilophodontidae (or Hypsilophodontia) is a traditionally used family of ornithopod dinosaurs, generally considered invalid today. It historically included many small bodied bipedal neornithischian taxa from around the world, and spanning from ...

Orodromeus ''Orodromeus'' (meaning "Mountain Runner") is a genus of herbivorous orodromine thescelosaurid dinosaur from the Late Cretaceous of North America. Only one species is known, the type species ''Orodromeus makelai''. Discovery and naming The rem ...

'', and horned dinosaurs ''

Achelousaurus ''Achelousaurus'' () is a genus of centrosaurine ceratopsid dinosaur that lived during the Late Cretaceous Period of what is now North America, about 74.2 million years ago. The first fossils of ''Achelousaurus'' were collected in Mont ...

'', ''

Brachyceratops ''Brachyceratops'' ('short horned face') is a dubious genus of ceratopsian dinosaur known only from partial juvenile specimens dating to the late Cretaceous Period of Montana, United States. ''Brachyceratops'' has historically been known from ju ...

'', ''

Einiosaurus ''Einiosaurus'' is a genus of herbivorous centrosaurine ceratopsian dinosaur from the Upper Cretaceous (Campanian stage) of northwestern Montana. The name means 'buffalo lizard', in a combination of Blackfeet Indian ''eini'' and Latinized Ancient ...

'', and '' Styracosaurus ovatus'' were also present. This formation was more distant from the Western Interior Seaway, and higher and drier than the Dinosaur Park Formation. The age of ''Prosaurolophus maximus'' remains from this formation is from approximately 75.5 to 74.0 million years ago.

Diet

''Prosaurolophus maximus'' itself lived in coastal floodplains and dined on conifer trees, implying that it was more likely a browser rather than a grazer.

References

External links

{{Commons category, Prosaurolophus, lcfirst=yes Late Cretaceous dinosaurs of North America Saurolophines Fossil taxa described in 1916 Taxa named by Barnum Brown Paleontology in Alberta Paleontology in Montana Campanian genus first appearances Campanian genus extinctions Ornithischian genera

Description

History of discovery

Classification

History of classification

Phylogeny

Paleobiology

Social behavior

Paleoecology

Diet

See also

References

External links