|
|
|
Country’s first dinosaur fossils
Although dinosaur fossils have been around for millions of years, and have been found even in India and China, the first Mesozoic dinosaur fossils from Pakistan were collected only recently from the Upper Cretaceous Pab Formation in Balochistan.
A team of palaeontologists from the Geological Survey of Pakistan (GSP) and the Michigan University, Ann Arbor, USA, made the discovery in 2001 in Vitakri area, Barkhan, Balochistan. Dinosaurs lived for nearly 150 million years (from 228 million years ago to 65mya), and then disappeared off the face of Earth in the most mysterious extinction ever. Many of them were gigantic, but some were no bigger than a chicken.
The important discoveries like that of dinosaurs, crocodyliform and walking whale made by GSP’s earth scientists have enhanced the importance of Pakistan for research in the field of palaeontology and have made the country known to evolutionary biologists the world over.
Recent geological and palaeontological exploration in the Pab Formation has uncovered new terrestrial vertebrate remains which provide information about the palaeobiogeographic history of the subcontinent during its northward migration towards Asia. Many of the dinosaur fossils collected from the surface by GSP palaeontologists belong to the Titanosaurus Sauropods type (plant-eaters), similar to fossils recovered from Bara Simla and Dongargaon, Central India.
Identification of five new genera from Balochistan and similarities between multiple localities across the subcontinent suggest that Cretaceous vertebrates were well distributed across territories making up India and Pakistan. The GSP geologists working on mineral exploration, geological mapping and field investigation in Barkhan area in 2000 unearthed fossils sticking right out of the ground in rocks of the Maastrichtian age.
The discovery produced a hype in the geoscientific community as dinosaurs were not reported earlier from this part of the world and the scientific importance of this discovery was that it was made in Cretacous rocks which were deposited 65 million years ago, close to the extinction of these giant reptiles.
Field investigations to be carried out by foreign scientists in Balochistan have been put on hold due to an indifferent law and order situation there. However, the local geologists are carrying out exploration work as usual
Geologists had reported locomotory organs, distal portion of humerus in the Pab Formation which is a gas- and oil-yielding formation. The early surface collection was made from the upper part of the formation which comprised chocolate maroon shales and black weathered sandstones. Fossils and fossil debris were found in the residual colluvium material having slopes of 20 to 40 degrees towards west.
Later excavations unearthed more than 2,700 dis-articulated fossils, attributable mostly to Titanosaur sauropods collected from a 50km wide area near Vitakri. These included a well preserved sauropod braincase, ear, maxilla, dentaries and jaw fragment. Some of these specimens were dispatched to the Museum of Palaeontology, University of Michigan, for further research and confirmation of findings.
A composite shape of the Titanosaurus skeleton has been reconstructed in the GSP’s Geological Museum, Quetta, for the visitors to appreciate the enormous size of this pre-historic reptile. Titanosaurus means titanic lizard.
It is a herbivore dinosaur, about 40 to 60 feet long and 10 feet tall at the hips. It was an armoured quadrupedal saurischia — a lizard-hipped dinosaur that walked on four legs and had a heavy body, weighing 14,700kg. It lived in this region in the late Cretaceous period, about 83 to 65mya.
It was an enormous dinosaur that had a long neck and a small head. Titanosuarus had a long, slender tail which was very useful. It may have used its tail as a sort of prop to support itself to reach the higher branches of trees. It also used it as a weapon, lashing it like a long, strong whip, much like Indiana Jones in the movie Raiders of the Lost Ark.
The last tail vertebra of the skeleton put on exhibit at the GSP Museum has marks that show that it may have used it to deliver painful blows to enemies attacking it.
The four sauropoda species identified so far have been named: Balochisaurus malkani, Khateranisaurus barkhani, Marisaurus jeffi and Sulaimansaurus gingerichi. Geologists have also found some plant remains which were preserved in the rocks. Eating a diet of plants causes animals many more problems than when they eat meat. Plants are made of tough material like cellulose and woody lignin which need to be broken down before digestion can take place in the animals’ stomach.
Plant-eating dinosaurs coped with their diet in a variety of ways: the sauropods did not chew at all, but simply swallowed raked-in vegetation. This passed directly to the stomach and was ground up by deliberately swallowed gastroliths, or gizzard stones.
All the meat-eating dinosaurs belong to a group called Theropods, which means beast footed. GSP Geologist Sadiq Malkani collected a pair of femur head, greater trocharter and a cross-section of shaft vertebrae of a theropod which might belong to T-Rex or Abelisaurid. The one new theropod species identified so far from Vitakri area by GSP geologists has been named Vitaridrinda sulaimani.
These meat-eating dinosaurs were called carnosaurs or flesh lizards — large animals with big heads, powerful legs and short arms. Like all theropods, they walked on two legs and pursued and ate other dinosaurs, and also fed on dead animals that they found like scavengers.
Tyrannosaurs rex is probably the best known (and most fearsome) of the carnosaurs. It was 49 feet long and had a massive skull with powerful jaws that held serrated teeth up to 7 inches long. Its tremendous head was five feet long. Their hands were also well equipped with sharp claws which they probably used to push themselves upright after lying down.
Fossils of dinosaurs on display at the GSP Museum of Geological History in Quetta are of great interest not only for vertebrate palaeontologists and other geoscientists, who seek to better understand the evolution of life on our planet, but common visitors as well. The museum houses one of the oldest and largest geological collections in the country. It once was a sleepy place with occasional visitors and many of its sections were in ruins.
However, it now is attracting a big number of enthusiasts and is gaining reputation as a centre of learning. The galleries of the museum offer the most comprehensive survey of the scientific discoveries made by GSP across the country.
Exhibits relating to the GSP’s research programmes are classified by each main theme of earth science. The treasure trove includes a collection of over 7,650 priceless geological specimens, including meteorites, rocks, minerals, gemstones, building and decorative stones and fossils put on display in its seven thematic galleries.
A huge amount of specimens are utilized by scientific researchers from the inside or outside of the organisation. Dinosaurs, Walking Whale, the largest land mammal of all times — the Baluchitherium — and the largest collection of Ammonites and other prehistoric animals and marine invertebrate fossils on display in this museum have an uncanny and unrivaled attraction for visitors.
The museum regularly arranges special exhibitions and various events for dissemination of geologic information to the public. Further details can be obtained by visiting GSP’s website at www.gsp.gov.pk.
The discovery of dinosaur fossils in Balochistan is expected to generate a lot of interest among geoscientists, especially since investigations are still continuing. Thick piles of Mesozoic sedimentary rocks are exposed in many parts of Sindh and Balochistan, but no remains of dinosaurs were unearthed before this discovery.
Claims were indeed made earlier too about the presence of dinosaur fossils in Ganjo Takar, Hyderabad and Salt Range areas, but these were not substantiated through papers in reputable scientific journals. Collaborative research with scientists from University of Michigan did produce outstanding results in the shape of co-authorship of research.
However, field investigations to be carried out by foreign scientists have been put on hold in Balochistan since 9/11 due to an indifferent law and order situation there. However, the GSP geologists are carrying out exploration work as usual, in an effort to find more fossilised remains.
The ongoing field work has already produced many interesting findings and the search is on for more and more fossils. The studies carried out by Pakistani scientists are expected to open up several new avenues of research, such as palaeogeographic location of the sea, past land bridges in southern and central Asia, migratory pathways of dinosaurs and other land animals like Baluchitherium.
These studies will be of great scientific value in relation to the worldwide phenomenon of iridium anomaly associated with the close of the Cretaceous period and the extinction of the giant reptiles. Work is also being carried out on the K-T boundary. The present dinosaur locality has been found on the northern side of the southern part of the Sulaiman Fold and Thrust Belt. GSP geologists have also produced geological maps of the Sulaiman Range.
The structural development of the area is the result of compression tectonics due to northward drifting of the Indo-Pakistani plate and its subsequent collision with the Asian plate during the post-Paleocene years.
The writer is the curator of GSP’s Geological Museum in Quetta
|
|
|
|
