Monolophosaurus

*Monolophosaurus jiangi*

* Jurassic Park Institute Artwork
* Robert F Walters Artwork

***Monolophosaurus jiangi*** (meaning "single-crested lizard") is an extinct genus of tetanuran theropod dinosaur that lived in westen China from Asia during the Jurassic period. Although similar to *Dilophosaurus* by the crests, they are not related. *Monolophosaurus* was closer related to the more advanced carnivores like *Allosaurus*. It is distinctive by the single crest on its skull, which was probably for mating.Its crest could also be used to intensify the roar, it could be useful in communicating in a flock while hunting. It lived with Eugongbusaurus, Hualianceratops, Jiangjunosaurus, Yinlong, Bellusaurus, Fushanosaurus, Klamelisaurus, Mamenchisaurus, Tienshanosaurus, Aorun, Guanlong, Haplocheirus, Limusaurus, Shishugounykus, Sinraptor and Zuolong.

## Discovery and naming

A nearly complete skeleton of a theropod new to science was discovered by Dong Zhiming in 1981, during stratigraphic exploration for the benefit of the oil industry. The fossil was not unearthed until 1984. In 1987, before description in the scientific literature, it was referred to in the press as *Jiangjunmiaosaurus*, an invalid *nomen nudum*. In 1992 it was mentioned by Dong Zhiming as *Monolophosaurus jiangjunmiaoi*, and in 1993 by Wayne Grady as *Monolophosaurus dongi*. These latter names also lacked a description and therefore were *nomina nuda* as well.

In 1993/1994, Zhao Xijin and Philip John Currie named and described the type species *Monolophosaurus jiangi*. The generic name is derived from Greek μόνος, *monos*, "single", and λόφος or λόφη, *lophos/lophè*, "crest", in reference to the single crest on the snout. The specific name refers to Jiangjunmiao, an abandoned desert inn near which the fossil was found. Jiangjunmiao means "the temple (*miao*) of the general (*jiangjun*)"; local legend has it that a general was buried here.

The holotype **IVPP 84019** was discovered in the Junggar Basin, in layers of the Wucaiwan Formation dating from the Bathonian-Callovian. It consists of a rather complete skeleton including the skull, lower jaws, vertebral column and pelvis. The rear of the tail, the shoulder girdle and the limbs are lacking. It represents an adult or subadult individual. The type specimen was restored with plaster to be used in a travelling exhibit. Its left side was encased in foam which has hindered subsequent study. A reconstruction was made of the missing elements to create casts of complete skeletal mounts. In 2010, two studies by Stephen Brusatte, *et al* redescribed the holotype, at the time still the only specimen known, in detail.

In 2006, Thomas Carr suggested that *Guanlong*, another theropod with a large, thin, and fenestrated midline crest and from the same formation, was in fact a subadult individual of *Monolophosaurus*. Usually *Guanlong* had been considered a proceratosaurid tyrannosauroid, but Carr had performed an analysis in which both specimens clustered and were allosauroids. More conservatively, in 2010 Gregory S. Paul renamed *Guanlong* into a *Monolophosaurus* species, *Monolophosaurus wucaii*, presuming the taxa might be sister species. In 2010, Brusatte e.a. rejected the identity, pointing out that the *Guanlong* holotype was actually a fully adult individual.

## Description

*Monolophosaurus* was a mid sized theropod that was about 5–6 meters in length, and weighing up to 1,500 pounds. This predator is most famous by its head crest, though it is more advanced then the primitive crested dinosaurs like *Dilophosaurus*. It was known to hunt in packs to bring downs sauropods like the more advanced carnivores during the later times of the Jurassic. It had lots of sharp, serrated teeth and a big, skinny head. The area that *Monolophosaurus* was found showed signs of water, so it is possible that this dinosaur probably lived on the shore of lakes and oceans. It possibly hunted defensive herbivores such as Tuojiangosaurus.

## Classification

*Monolophosaurus* was originally termed a "megalosaur" and has often since been suggested to be an allosauroid. Smith *et al.* (2007) was the first publication to find *Monolophosaurus* to be a non-neotetanuran tetanuran, by noting many characters previously thought to be exclusive of Allosauroidea to have a more wider distribution. Also, Zhao *et al.* in 2010 noted various primitive features of the skeleton suggesting that *Monolophosaurus* could be one of the most basal tetanuran dinosaurs instead. Benson (2008, 2010) placed *Monolophosaurus* in a clade with *Chuandongocoelurus* that is more basal than Megalosauridae and Spinosauridae in the Megalosauroidea. Later, Benson *et al.* (2010) found the *Chuandongocoelurus*/*Monolophosaurus* clade to be outside of Megalosauroidea and Neotetanurae, near the base of Tetanurae. A 2012 phylogeny found *Monolophosaurus* and *Chuandongocoelurus*, while not sister taxa, to form a group outside more derived groups at the base of Tetanurae.

## Paleobiology

The type specimen (IVPP 84019) had its tenth and possibly eleventh neural spines fractured. They are fused together. A series of parallel ridges on one of the specimen's dentaries may represent tooth marks.

## JPInstitute.com Description

Monolophosaurus was a medium-sized meat-eater from China that lived during the Jurassic Period. It had lots of sharp teeth and a big, skinny head. It also had one feature not found on any other meat-eating dinosaur - a long, bony ridge that went from its nose back to the top of its head. The area where Monolophosaurus was discovered showed signs that it was sometimes covered with water, so it is possible that this dinosaur lived on the shore of a lake or sea.

There is still uncertainty concerning the family association of Monolophosaurus. Although it is currently assigned to the megalosaur family, it has been suggested that it may be more closely related to the allosaurs.

## Dinosaur Field Guide Description

Monolophosaurus ("single-crested lizard") was the top meat-eating dinosaur in China about the same time that Megalosaurus ruled England. In many ways it was a typical medium-sized Jurassic theropod. Its skull was about 2.25 feet (67 cm) long; it stood about 5.75 feet (1.7 m) high at the hips, and its jaws were filled with blade-like teeth for slicing through meat. The most outstanding feature of Monolophosaurus was its crest. Other meat-eating dinosaurs had crests or horns on their heads, but nothing quite like that of Monolophosaurus. The single fat crest ran from the tip of its nose to just above its eyes. The bones of this crest were hollow, but it was not connected to the windpipe, so it couldn't be used to make sounds the way that some duckbills could. Instead, this crest was probably hollow so that it didn't weigh down the dinosaur's head too much. What could this crest have been for? Many modern animals have horns or fan tails or other features that are used for display, to show off in order to win mates or defend territory. It seems likely that Monolophosaurus did the same thing with its crest.

### Fun Facts

Many dinosaur fossils are found by accident. Monolophosaurus, for example, was found by geologists searching for oil deposits.

### Trivia

Monolophosaurus's crest may have been brightly colored, but this is just a speculation. Unfortunately, color is not preserved in the fossil record.

## Appearance in other media

### *Jurassic Park*

* *Monolophosaurus* is no. 010 of the Carnivore Twos that can be created in Jurassic Park III: Park Builder.
* *Monolophosaurus* appears in Jurassic World: The Game. It originally wasn't in the game but since August 4, 2015 it can be created for the player's park by unlocking it in the Level 55 battle arena.
* *Monolophosaurus* appears in Jurassic World: Alive.
* A *Monolophosaurus* figure was released as part of the toy-line for Jurassic World: Fallen Kingdom, as part of the "Battle Damage" line. This is the first time it has ever physically appeared in any Jurassic Park toy set.
* Monolophosaurus appeared in the TV series Jurassic World: Camp Cretaceous.

## Links

http://web.archive.org/web/20040419175736fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_monol.html
https://web.archive.org/web/20080821175155/http://kids.yahoo.com/dinosaurs/327--Monolophosaurus