Alioramus ‭(‬Different Branch‭)

Short Info

Alioramus ‭(‬Different Branch‭)

Phonetic : Ah-lee-oh-ray-mus

Named By : Sergei Kurzanov‭ ‬-‭ ‬1976

Diet : Carnivore

Size : Estimated 6 meters long

Type of Dinosaur : Large Theropod

Type Species : A.‭ ‬remotus‭ (‬type‭)‬,‭ ‬A.‭ ‬altai

Found in : Mongolia

When it Lived : Late Cretaceous, 71-65 million years ago

Alioramus (/,aelioU’reIm@s/ (meaning “different branch”) is the name of a species that includes theropod dinosaurs that tyrannosaurids were from early in the Late Cretaceous period of Asia. There are currently two species. The most well-known species, A. remotus is identified from a skull fragment along with three bone fragments from the foot found in the Mongolian Nemegt Formation that was found in a moist floodplain around 70 million years old. The remains were identified as well as described by Soviet paleontologist Sergei Kurzanov in 1976. A other specie, A. altai, is known for its more complete skeleton was identified as well by Stephen L. Brusatte and colleagues in the year 2009. Its ties to other tyrannosaurid genera are not clear There is evidence that supports the idea the possibility that Alioramus has a close relationship with the current species Tarbosaurus bataar.

Alioramus were bipedal as are all theropods that are known to exist Their sharp teeth suggest these were carnivores. The known specimens are smaller in comparison to other Tyrannosaurids such as Tarbosaurus bataar or Tyrannosaurus Rex, however their adult size is hard to calculate because each Alioramus species are only known from the remains of sub-adults or juveniles. The discovery of Qianzhousaurus is a sign that it is a distinct tyrannosaur branch. The Genus Alioramus is identified by the presence of five bony crests that run along the snout’s top and a higher amount of teeth than other genus of tyrannosaurids and a skull that is lower than the majority of other tyrannosaurids.

 

Texas Alioramus
Texas A&M University-Commerce Marketing Communications Photography, CC BY 2.0, via Wikimedia Commons

The Holotype (PIN 3141/1) of Alioramus is a skull fragment connected to three metatarsals. An expedition of the Soviet Union and Mongolia in the Gobi Desert in the 1970s found these remains in a region called Nogon-Tsav located in the Mongolian province of Bayankhongor, Nemegt Formation. Alioramus was identified and described in the work of Russian paleontologist Sergei Kurzanov in 1976. The crests and the low skull appearance were different from other tyrannosaurids Kurzanov believed that his discovery was distinct from other members of his family. So, he assigned the species an unspecified name Alioramus which is derived from the Latin Alius (‘other’) and ramus (‘branch’), and the precise name A. Remotus meaning’removed’ in Latin. A different kind of species called A. altai was first discovered in 2001 in Tsagan Khushu. Tsagan Khushu locality also from the Nemegt Formation. But, the presence of several differences in the fauna might suggest that the localities of A. Remotus A. remotus and A. altai are different in terms of age. The IGM 100/1844 holotype IGM 100/1844 is fragmented skull that has a full skull, much more than A. Remotus, which has a few vertebrae, pelvic and hindlimbs. The name of this species altai is a an allusion to the Altai Mountains.

Alioramus remotus was thought to be 5-6 m (16 to 20 feet) in length at the time it was recorded in the work of Sergei Kurzanov in 1976. In 1988, Paul provided a length of 6 meters (20 feet) and 700 kilograms (1,500 lbs). In 2016, Molina-Perez and Larramendi estimate A. Remotus at 5.5 metres (18 feet) as well as 500 kilograms (1,100 lbs) and A. altai as 5 metres (16 feet) with 385kg (849 lbs). Kurzanov however, was not able to adjust for the lengthening of the skull as a result of fossilization deformation that could suggest the shorter length of the body overall for this particular animal. The specimen could be child, then the adult Alioramus could have grown to greater lengths, but no adult specimens are available.

 

Alioramus altai skull at Wyoming Dinosaur Center
Clément Bardot, CC BY-SA 3.0, via Wikimedia Commons

The skull of A. Remotus was around 45 centimeters (1.48 feet) long. It is generally high and long and a typical shape of tyrannosauroids with more basal structures and the juveniles of larger tyrannosaurids. The premaxillary bones located at the top of the snout of the Alioramus Remotus have not been discovered and are not as tall as broad in the tyrannosauroids which they are recognized. Nasal bones have been fused together and embellished with five bony crests with irregular shapes that rise toward the middleline, which is where they are sewed to each other. These crests each measure over 1 centimeter (0.39 in) tall.

In the side of the skull is a protrusion called the nuchal crest. It is formed from the parietal bone fused which is a characteristic shared by all Tyrannosaurids. In Alioramus the nuchal crest has been greatly in thickness, similar to Tarbosaurus as well as Tyrannosaurus. Similar to the other skulls The lower jaw in Alioramus is long and slim and slender, a characteristic that could be attributed to a juvenile. Similar to Tarbosaurus there was a ridge that ran along the outside of the bone in the lower jaw was articulated with the back teeth of dentary bones connecting the two bones and taking away a lot of the flexibleness that other tyrannosaurids have. The other tyrannosaurids also had four premaxillary teeththat were that were D-shaped in cross-section on either side. In addition to 16 or 17 in each maxilla and 18 in each of the dentary teeth, Alioramus had 76 and 78 teeth, which is more than other tyrannosaurids. Braincases of A. altai was intermediate between the basal and conditions of the avialan.

The remainder of the structure of the Alioramus Remotus is largely unknown with the exception of the three metatarsals (bones of the foot’s upper part) however, discovering A. altai, which is evident from much larger remains has shone more light regarding the anatomy within the Genus.

Source: Wikipedia