Olorotitan was a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of lambeosaurine

Lambeosaurinae

Lambeosaurinae is a group of crested hadrosaurid dinosaurs.-Classification:Lambeosaurines have been split into Parasaurolophini and Corythosaurini . Corythosaurini and Parasaurolophini as terms entered the formal literature in Evans and Reisz's 2007 redescription of Lambeosaurus magnicristatus...

 duckbilled

Hadrosaurid

Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper...

 dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

 from the middle or latest Maastrichtian

Maastrichtian

The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...

-age Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 Tsagayan Formation beds located in Kundur, Amur

Amur Oblast

Amur Oblast is a federal subject of Russia , situated about east of Moscow on the banks of the Amur and Zeya Rivers. It shares its border with the Sakha Republic in the north, Khabarovsk Krai and the Jewish Autonomous Oblast in the east, People's Republic of China in the south, and Zabaykalsky...

 Region, Far Eastern Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

. The remains, consisting of a nearly complete skeleton, were described by Pascal Godefroit et al. in mid-2003. The generic name means “gigantic swan

Swan

Swans, genus Cygnus, are birds of the family Anatidae, which also includes geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometimes, they are considered a distinct subfamily, Cygninae...

” while the specific descriptor refers to the location of the fossil find at Arhara County. Olorotitan is distinct from other crested duckbills by its possession of an unusual crest that points backward and takes on a hatchet

Hatchet

A hatchet is a single-handed striking tool with a sharp blade used to cut and split wood...

 or fan

Fan (implement)

A hand-held fan is an implement used to induce an airflow for the purpose of cooling or refreshing oneself. Any broad, flat surface waved back-and-forth will create a small airflow and therefore can be considered a rudimentary fan...

-like shape. Its discovery has implications for the diversity of lambeosaurine hadrosaurid

Hadrosaurid

Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper...

s.

Description

Olorotitan is based on the most complete lambeosaurine skeleton found outside North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 to date. It was a large hadrosaurid, comparable to other large lambeosaurines like Parasaurolophus cyrtocristatus

Parasaurolophus

Parasaurolophus is a genus of ornithopod dinosaur that lived in what is now North America during the Late Cretaceous Period, about 76.5–73 million years ago. It was an herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P. tubicen, and the...

, and may have grown up to 12 meters long (39 ft). It is characterized by numerous unique features for a hadrosaurid, the most obvious being the large hatchet-like hollow crest adorning its skull. The skull itself is supported by a rather elongated neck, having 18 vertebrae, exceeding the previous hadrosaurid maximum of 15. The sacrum

Sacrum

In vertebrate anatomy the sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx...

, with 15 or 16 vertebrae, has at least 3 more vertebrae than other hadrosaurids. Further along the vertebral series, in the proximal third of the tail, there are articulations between the tips of the neural spines

Spinous process

The spinous process of a vertebra is directed backward and downward from the junction of the laminae , and serves for the attachment of muscles and ligaments. In animals without an erect stance, the process points upward and may slant forward or backward...

, making that caudal area particularly rigid; the regularity of these connections suggests that they are not due to a pathology

Pathology

Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....

, although more specimens are needed to be certain. Godefroit and his coauthors found through a phylogenetic analysis

Cladistics

Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 that it was closest to Corythosaurus

Corythosaurus

Corythosaurus is a genus of duck-billed dinosaur from the Upper Cretaceous Period, about 77-76.5 million years ago. It lived in what is now North America...

and Hypacrosaurus

Hypacrosaurus

Hypacrosaurus was a genus of duckbill dinosaur similar in appearance to Corythosaurus. Like Corythosaurus, it had a tall, hollow rounded crest, although not as large and straight...

.

Paleoecology and paleobiology

Olorotitan shared its time and place with several other types of animal, including two other lambeosaurines: the Parasaurolophus

Parasaurolophus

Parasaurolophus is a genus of ornithopod dinosaur that lived in what is now North America during the Late Cretaceous Period, about 76.5–73 million years ago. It was an herbivore that walked both as a biped and a quadruped. Three species are recognized: P. walkeri , P. tubicen, and the...

-like Charonosaurus

Charonosaurus

Charonosaurus |Charon]]'s lizard") is the name of a genus of dinosaur whose fossils were discovered by Godefroit, Zan & Jin in 2000 on the south bank of the Amur River, dividing China from Russia.-Description:...

and more basal

Basal (phylogenetics)

In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...

 Amurosaurus

Amurosaurus

Amurosaurus is a genus of lambeosaurine hadrosaurid dinosaur found in the latest Cretaceous period of eastern Asia. Like most lambeosaurs, it would have been a primarily bipedal herbivore with a "duckbill" shaped snout and a hollow crest on top of its head, although such a crest has not been found...

. Additionally, remains from turtle

Turtle

Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...

s, crocodilians, theropods, and nodosaurids were found at its discovery site, and the Saurolophus

Saurolophus

Saurolophus is a genus of large hadrosaurine duckbill that lived about 69.5-68.5 million years ago, in the Late Cretaceous of North America and Asia; it is one of the few genera of dinosaurs known from multiple continents. It is distinguished by a spike-like crest which projects up and back...

-like hadrosaurine

Hadrosaurinae

Saurolophinae is a subfamily of hadrosaurid dinosaurs. Members of the subfamily derive from the Late Cretaceous of Antarctica, Argentina, Canada , China, Kazakhstan, Mexico, Russia, the United States and...

 Kerberosaurus

Kerberosaurus

Kerberosaurus was a genus of hadrosaurine duckbill dinosaur from the late Maastrichtian-age Upper Cretaceous Tsagayan Formation of Blagoveschensk, Amur Region, Russia...

is also known from roughly contemporaneous rocks in the area. Unlike the situation in North America, where lambeosaurines are essentially absent from Late Maastrichtian rocks, Asian lambeosaurines are diverse and common at the end of the Mesozoic, suggesting climatic

Climate

Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...

 or ecological

Ecology

Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...

 differences.

As a hadrosaurid, Olorotitan would have been a bipedal/quadruped

Quadruped

Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...

al herbivore

Herbivore

Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

, eating plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

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

Mastication

Mastication or chewing 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 more efficient break down by enzymes. During the mastication process, the food is positioned between the teeth for grinding by...

, and was furnished with hundreds of continually-replaced teeth

Tooth

Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...

. Its tall, broad hollow crest, formed out of expanded skull bones containing the nasal passages, probably functioned in identification by sight and sound.