“Lonely Small Bandit” Confirms Hypothesis that Abelisaurid Fossils were Awaiting Discovery
The United States, Canada and possibly Mexico may be able to lay claim as being the home of Tyrannosaurus rex but the island of Madagascar can take ownership of another short-armed Cretaceous terror, with the announcement of the discovery of a new genus of Abelisaurid. Although, very fragmentary and consisting of a handful of vertebrae and bone fragments the fossils are distinct enough for palaeontologists to assign them to a brand new genus of Abelisaur, the first new species/genus to be described from Madagascar in almost ten years.
Fossils of Late Cretaceous Carnivorous Dinosaur From Madagascar
The fossils were found in Upper Cretaceous strata and have been dated to the Cenomanian faunal stage, approximately 90 million years ago. They were found near to the city of Antsiranana (formerly known as Diego-Suarez), in the Diana region of northern Madagascar. First evidence of the fossils was discovered in 2007 and a second expedition to extract more fossil material took place in 2010. It was Dr. Joseph Sertich, curator of Vertebrate palaeontology at the Denver Museum of Nature & Science who discovered the dinosaur in a collaborative venture with the Raymond M. Alf Museum of Palaeontology (California, United States). This new Theropod has been named Dahalokely tokana (pronounced Dah-hah-loo-kah-nah), it means “lonely small bandit” in the local dialect, a reference to the size of this dinosaur relative to other known Abelisaurids from the southern hemisphere and from the fact that when this dinosaur roamed, Madagascar had separated from the landmass of Africa.
Dahalokely tokana – “Lonely Small Bandit”
Madagascar, is regarded by many scientists as the “world’s oldest island”, its isolation for millions of years explains the unique fauna and flora to be found, on what is today the world’s fourth largest island with a total area of more than 2.25 times the size of the United Kingdom. The researchers have declared this discovery as providing a link between older Abelisaurid fossil material and younger fossils dated to near the end of the Cretaceous geological period. They describe the fossils as helping to plug an important gap in knowledge regarding the evolution of the Abelisaurids.
Up to Four and Half Metres in Length
Estimated to have measured between three and four and half metres in length, this bipedal predator may have stood something like one and a half metres high at the hips. D. tokana is known from a handful of cervical vertebrae (neck bones), dorsal vertebrae, (back bones) and fragments of rib. Distinct and unique features on the vertebrae led the scientists to assign the fossil material to a new species, representing the first dinosaur to be described from rocks laid down when Madagascar and India were joined together (Indo-Malagasy landmass). Up to the discovery of D. tokana, no dinosaur fossils from between 165 million years old to around 70 million years of age could be identified and classified down to species level. This significant gap has been reduced to 165 – 90 million years approximately.
Ancestral to Both Indian and Later Madagascan Meat-eating Dinosaurs?
Something like two million years after this dinosaur existed, Madagascar split from India. A rising plume of extremely hot, molten rock began to force its way up into the crust from the mantle under the Indo-Malagasy landmass and this began to stretch the crust forcing it to rift apart. This rifting led to the separation of India and Madagascar. The fact that this new species of Abelisaurid lived before the split has led to speculation that this type of dinosaur may have been ancestral to the later Abelisaurs of India, large super-predators such as Rajasaurus (R. narmadensis) and Late Cretaceous Abelisaurs from Madagascar, dinosaurs such as Majungatholus also known as Majungasaurus. The research team hope to find more fossils of Dahalokely so that they can determine the taxonomic relationships between these different types of carnivores.
Commenting on the significance of this dinosaur discovery Dr. Sertich stated that this new type of dinosaur was closely related to other better known Abelisaurids from the southern hemisphere. This discovery reinforces the importance of exploring more remote parts of our planet to find and uncover new dinosaur genera.
Project leader, Andrew Farke, (Augustyn Family Curator of Palaeontology at the Raymond M. Alf Museum of Palaeontology) said that palaeontologists had always suspected that other Abelisaurid fossils were awaiting discovery from strata aged between ninety and one hundred million years of age. The fossils although far from complete are providing vital clues as to the ancestry and evolutionary development of large, meat-eating dinosaurs from the landmass that was once the super-continent of Gondwanaland.
More Questions than Answers when it Comes to the Dinosauria
As with many dinosaur discoveries, this fragmentary specimen leaves more questions unanswered than answered but it has potentially provided important evidence linking Indian Abelisaurids and Madagascan Abelisaurids to a common ancestral form.