narmadensis Archives - The Big Dinosaur Podcast

Episode 115 is all about Rajasaurus, an abelisaurid theropod with an unusual head crest.

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In this episode, we discuss:

Abelisaurian theropod with an unusual head crest
Found a partial skeleton (part of the skull, backbone, hip bones, parts of the hind legs, and tail)
Described in August 2003

Discovered by Suresh Srivastava of the Geological Survey of India between 1982-1984
Excavated in the Kheda district of Gujarat, India
In 1981 workers from a cement quarry showed geologists G.N. Dwivedi and D.M. Mohabey ball-like structures they’d found, which were dinosaur eggs (beneath the eggs were fossils)

Between 1982-84, Suresh Srivastava collected fossil fragments and worked on cleaning the bones with U.B. Mathur and S.C. Pant (then nothing really happened for a few years), and created a detailed map
In 2001, Sereno and Wilson started to reconstruct those bones and then formally described Rajasaurus in 2003 (found the bones in the Geological Survey of India museum, and didn’t realize its significance at first)
However, fossils described in 1923 may also belong to Rajasaurus. Charles Matley collected bones between 1917 and 1919, and at first (1921) he thought all the bones he found were from a single specimen of a new theropod (though the ilia and sacrum were found in close approximation). Then in 1923 Matley interpreted some of those bones (ilia, sacrum, tibia, scutes) as part of a new stegosaur, named Lametasaurus indicus. However, no stegosaur bones found in India share derived characters with it, so in 1935 Chakravarti suggested the ilia and sacrum (which are now lost) were part of a theropod. It’s unclear if the scutes are part of it (could also be part of titanosaurs found nearby)

Type species is Rajasaurus narmadensis
Species name means “from the Narmada Valley”
The Narmada River where it was found has also yielded other dinosaur bones (some found in the late 1800s), including Titanosaurus indicus

Rajasaurus has only been found in India, which at the time it lived had recently moved away from Gondwana and started moving north
Rajasaurus is the first theropod found in India with preserved cranial and postcraniel remains (part of the skull), which means it can help scientists learn more about how abelisaurs evolved, since specimens described from India previously were mostly isolated bones
Rajasaurus is similar to other abelisaurids, including Majungasaurus from Madagascar, and Carnotaurus, from South America (had a common ancestor)

Compared to tyrannosaurs, which dominated northern continents and lost ornamental structures on their heads, abelisaurids like Rajasaurus, Majungasaurus, and Carnotaurus, had more skull ornamentation as they became more advanced
Rajasaurus was found in the Lameta Formation, which have volcanic rocks (Deccan Traps), so Rajasaurus and other sauropods from there were buried quickly by Deccan volcanic flows
About 25-29.5 ft (7.6-9 m ) long

Had a low rounded horn, which grew from its nasal bones (similar to Majungasaurus)
Can see a life-size fiberglass model of Rajasaurus at the Geological Survey of India’s Lucknow regional office
In Adlabs Imagica, India, there’s a Jurssic Ride Rajasaurus River Adventure (similar to the Jurassic Park ride at Universal)

Can also see Rajasaurus in the game Jurassic Park: Builder (acquire it in Tournament Mode)
Abelisauridae means “Abel’s lizards”
Clade of ceratosaurian theropods that lived in the Jurassic and Cretaceous in Gondwana (Africa, South America, India, and Madagascar)

Jose Bonaparte and Fernando Novas named Abelisauridae in 1985, when they described Abelisaurus (named after Roberto Abel, who discovered Abelisaurus)
Bipedal and carnivorous
Had short hindlimbs and ornamentation on the skull bones

Skulls were generally tall and shallow
Four digits on the hand
Abelsaurids are also part of the group ceratosaurs (Limusaurus and Ceratosaurus had short arms in the Jurassic, like abelisaurids)

Fun fact: There are 13 states (and Washington D.C.) that have a state dinosaur and/or a dinosaur as the state fossil. The states with a state dinosaur or state fossil that’s a dinosaur are: Colorado, Connecticut, Maryland, Massachusetts, Missouri, Montana, New Jersey, New Mexico, Oklahoma, South Dakota, Texas, Utah, Wyoming.

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