Editorial – Geography Watch – On the trails of Indian Dinosaurs !!!

Note- The article is little technical in nature. It also refers to different geological timescale, here is a list for better understanding :-

In the early 1800s European priests and doctors visiting India found ample dinosaur remains strewn about the place. In fact, one such gentleman – a captain, is fondly remembered with the city Sleemanabad (located midway between Allahabad and Jabalpur) dedicated to him. Major General William Henry Sleeman, the dinosaur `bone collector’ was a famous man indeed.

Well, there have been many more after him, and not all of them are Europeans. Sohan Lal Jain and Sankar Chatterjee are names that hold great reverence in this field.

It is now time to discover the wonder of our desi dinosaurs. When did they live? Of course, in the same age as the other dinosaurs of the world. Perhaps it was Permian period of the Palaeozoic era when it all began, with early dinosaur like creatures, Endothiodon, slowly roaming the earth. Then, with time and evolution, Triassic saw the development of our now familiar dinosaur. Although it was the period of Jurassic that laid claim to the fastest and the cunningest of the creatures.

Ossified Skin of an Indian Dinosaur (Left) and Cross Section of the Ossified Skin (Right)

By Cretaceous, life changed! There are several theories as to why it changed. Some say that meteors struck the earth’s surface, while others stress on the increased volcanic activity both of which caused huge dark clouds to wipe out all plant forms. Plant life was rapidly snuffed out due to lack of sunlight and only those that could live in near darkness, survived.

The Lumbering Endothiodon

What kind of plants were these? Essentially ferns, fossils, which may be found in the coal seams that belong to the age. As a result the food chain was grossly disturbed and dinosaurs breathed their last.

Still others say that sea level changes affected plant life adversely. How? Well, as the sea level began to fall, perhaps due to the onset of an ice age, the lands which lay in the heart of the continent became dry and harsh due to continentality.

With such a development, the plant life found itself unable to adapt, thus wiping out the dinosaur population which depended upon them. However, we may add that it is not as if fauna and flora cannot adjust to change. But change has to be gradual, only then the flora of an area finds sufficient time to adapt and survive. A cataclysmic event, much like what happened here, doesn’t allow much scope to adjust.

And yes, we do have craters to prove that meteors did hit the land we call India. Have you visited the Lonar Lake in Maharashtra? Well, it is a crater. Moreover, the volcanic activity of the Deccan influenced the slow deterioration of the food web by blocking out sunlight.

However, whatever the reasons, the end of Cretaceous saw a new world order. Now it was the turn of the mammals to rule. But then, do dinosaurs have no present day descendants? Of course they do. Two living legends belong to the crocodile and the delightful bird family. Birds, the flying dinosaurs, in fact are theropods, which provide the missing link between dinosaurs of the past and the present.

When dinosaur roamed the earth, was India located where it is presently?
Not really! India was located in the southern continent in the Permian epoch. All clubbed together- India, Africa, Australia and Madagascar were ancient lands upon which Endothiodon, a slow moving reptile, lazily sauntered.

Parasuchians – Ancestors of the Modern Day Gharial

Then as the epoch progressed, the lands separated from each other and by Jurassic, India had drifted northwards nearer the tropics. By Cretaceous, India was closer to the equator. In fact, most scientists believe that our nation behaved like Biblical Noah’s arc, carrying varied flora and fauna through a long journey of time over 15-20 million years. The Indian landmass was reconnected with ‘land’ along the southern shores of Asia around 55 million years ago.

The Seaways of Cretaceous India

It was then that the Himalayas began to rise due to the northward push of the Indian Peninsular block.

And which small island, do you think, accompanied our peninsular block part of the way? Yes, it was Madagascar. However, about 80 million years ago, they were unfortunately separated, to follow their own paths.

How do we know this? Well, geological and paleontological evidences give clues which help us solve the puzzle of the drifting continents.

Did our peninsular block look just the same during the Cretaceous period? It would perhaps be erroneous to assume that. Evidences suggest that the landscape that you are now familiar with was broken in two places. One arm of the sea pushed inland from the west, in the present valley of Narmada, known as the Narmada seaway, while another, which lay in the southeast corner of present day India, the Godavari seaway, extended inland along the present valley of Godavari.

Why are these seaways so relevant? Well, it seems that dinosaurs were rarely found far from the arm of these seaways. Thus fossils, remains and eggs of the Cretaceous dinosaurs are easily found in these areas.

Plateosaurus – the large thumb claw owner

So much for the ancient Indian landscape, what about the dinosaurs that called India their home?
Before dinosaurs as we know them from Spielberg’s thrillers evolved, Endothiodons ruled the world (table 1). Beginning from the Permian what were the interesting creatures that lived here? There was a land and water loving amphibian named Archegosaurus, besides other fish and shark like creatures. And of course there was our low-bellied Endothiodon, grand daddy of dinosaurs.

However only about 20 per cent of all creatures that were known in the Permian managed to survive in the Triassic epoch. Why? Well, because there was a catastrophe which led to mass extinction. A sudden change in climate, a drop of oxygen levels and the skies above covered with smoke and ash from the Siberian vulcanism cut out the sunlight and filled the air with toxic gases.

However, thankfully the ancestors of man and the dinosaurs survived. Thecodonts or small two and four footed carnivorous animals began to gain prominence in this adaptation period. Early crocodiles, proter-osuchians evolved in this period.

In fact India had an animal called the Parasuchus hislopi, which was perhaps somewhat like our modern day gharial. They were excellently adapted for land and water, blissfully basking on the banks, devouring Triassic fish and other poor creatures that happened to visit the water hole.

Another creature, the Rauisuchians were ferocious thecodonts of the age. Look at the picture – their jaws do look awesome! However you would be surprised to know that these poor beasts, Indian one called Paradepedon huxleyi, perhaps ate only snails and molluscs, cracking their hard shells open with these powerful jaws.

Rauisuchian – Paradepedon Huxleyi

As dinosaurs evolved they became fast moving, larger and bipedal, and slowly moved up the food chain to become top predators. In fact, the earliest dinosaur of the Triassic, Alwalkeria maleriensis, was a cunning little chap. He could even hunt down our snail cracking Paradepedon huxleyi, who was no doubt a slow moving hunter of the times and no match for the athletic Alwalkeria.

Nearing the end of Triassic, fossils of Plateosaurids are found. These were the ancestors of the better known four legged huge sauropods of the Jurassic. These creatures roamed languidly over the plains clasping food with their huge thumb claws, chewing them thoughtfully with peg like teeth.

But again suddenly, all good things came to an abrupt end. Severe dry conditions prevailed for a continuing period which wiped out several plant species. The food chain was again disturbed. But then, after the darkest night we do see the glimmer of day light – at least that is what we have experienced uptil now. Thus fair weather again took charge and dinosaurs increased in size and adapted to a whole new world.

In fact these animals could give a run for the poor thecodont’s life, who uptil now co-existed with his faster descendants. It is also known that between the dinosaur stage and the thecodont stage, a coelosaus stage also existed. The coelosaus were small, very agile little fellows and have been grouped as early dinosaurs. Thus the change from thecodonts to a full fledged dinosaur took over 5 million years, by the end of which the dinosaur constituted more than 60 per cent of the known vertebrates of the time.

And when do you think this happened?
Yes, it was during the Jurassic! The saurids (reptiles) grew larger and two of them; Barapasaurus tagorei and Kotasaurus were huge creatures towering over 4 to 5 m in height and 24 m in length. In fact we have a story behind why they were called what they are! `Bara’ ‘pa’ would literally means big foot; which is indicative of the huge femur bone of 1.7 m found initially, before the rest of the fossil was unearthed. Why tagorei? Well, because the day it was discovered happened to be the birth centenary of Guru Rabindranath Tagore. As for Kotasaurus it was unimaginatively named after the bed of find.

Barapasaurus (The Big Footed Reptile)

But, whatever the stories, it was a remarkable find. So unique was this immense animal that its skeleton was found to be modified so that its mobility and efficiency stood uncompromised.

How was the skeleton modified? Well, besides the bones that formed the support of the barapasauras, the other bones were hollow and light. It also had huge pillar like legs to support its immense weight and a relatively small skull. This herbivorous saurid munched its food with spoon like teeth.

You will find it interesting to note that teeth structure of dinosaurs were quite different from mammals. Why? Because if you loose your permanent teeth, beware of brawls, you wouldn’t be able to grow it again. On the other hand unlike our two sets of teeth dinosaurs could grow any number of sets all its life. Old age thus posed no problem for him and munching was easy as ever.

Well, to get on with it, let us discuss another Indian dinosaur of the age, known as the Stegosaurus. It supported large bony plates made of skin. Although initially assumed to be armour, it was later conjectured that these plates may have been a heat regulating mechanism as it contained many blood vessel openings. Still others have argued that in all probability these plates may be gender specific, owned and perhaps prominently displayed by the males!

Then we had our Diplodocine, who in all probability, dominated the scene in the end Jurassic and early Cretaceous. It had long necks with pillar like legs that supported a small skull besides its immense body.

As we move on to Cretaceous, another dinosaur, the Titanosaurus colberti emerged. A huge plant eating species, aptly named, was about 25 m in length and 15 m in height. However, perhaps all of them weren’t this large.

Titanosaurus (The Large Plant Eating Reptile)

Titanosaurus was represented in six different types of genera, marked with a difference in size and appearance. Also the teeth of this dinosaur seemed rather small for supporting such an immense frame. Scientists believe that it probably had some other means of digesting food. One suggestion points towards little pebbles, which were swallowed, to aid the animal in grinding food in the stomach. What an innovative use for pebbles that we wistfully toss away! However, we forbid you to try such an experiment on yourself or anyone!

Well, despite its size, the world wasn’t safe for our Titanosaurus. Why? Because we can hardly dare to forget the two ferocious Abelisaurids – Indosuchus raptorius and Indosaurus matleyi. These were the Indian answers to the world famous Tyrannosaurus rex. They were ferocious predators that slashed their victims open with their huge serrated teeth. The front teeth were incisor like while the teeth that lay in the posterior were nearly 8-10 cm. long. Indeed a force to reckon with!

Indosuchius (Indian Answer to T. Rex)

Finally we have the Nodosaurid ankylosaur, a herbivorous four footed dinosaur. These fellows had a triangular skull with a small and slender face. Its body was heavily armoured with heavy bony spikes. However, unlike many others which were found with clubs on their tails, the Indian species lacked such an appendage.

Ankylosaurus (The Slender Headed Herbivore)

Before ending this discussion it would be important to remember that when we discuss certain creatures in a specific epoch, it does not necessarily mean that the others have all disappeared. The issue is relative! In relation to many other critters that were found, the ones that we specially discuss in a certain era, gained importance and were the prime most species of those times.

Stegosaurus (Creature with Bony Plates of Skin)

Secondly, a fact worth mentioning is that along with the dinosaurs there were many other creatures belonging to the mammalian species that existed at the same time. Besides, over and above the dinosaurs that have achieved status in this feature, there were many other dinosaur genera which were found in India. They include Dravidosaurus, Antarctosaurus, Compsosuchus, Laevisuchus, Laplatasaurus, Jubbulpuria, Brachypodosaurus, Dryptosauroides, Lametasaurus, Ornithomimoides, and Orthogoniosaurus.

However, we need detailed research on these before we can decide what they looked like or how they led their lives.

Thirdly, the world was different from as we know it today. There were land bridges and interconnections that allowed the migration of plants and animals. Thus it would be wrong to assume that India was an isolated sphere. In fact, all our dinosaurs are in some way connected to the larger species that roamed worldwide. It must not be assumed that our study shows genera of dinosaurs which have evolved in isolation.

Finally it would perhaps be worthwhile to remember that fossil remains are always not bones. It may be anything that living creatures leave behind, from droppings to paw prints on the wet mud. In fact extensive studies are carried out on brain cases, coprolites or dung and footprints to arrive at fairly accurate records of what the creature ate and how he lived.

It is indeed hard to believe that these animals were similar to our modern day wild life, where some creatures prefer to roam in solitary abandonment while others saunter in herds. Perhaps they were even capable of intelligent coordinated killings – who knows?

Keeping the above in mind it is time to shut the time capsule and bring you to an age where clouded acrid skies, burnt plants and dying moans of the huge dinosaurs is all you can visualise. Yes, by the end of Cretaceous, about 65 million years ago, it was time for the mammals to take over.

Diplodocine (The Dinosaur with a Long Neck and a Small Skull)

Where can we find dinosaur materials in India?
Dinosaur remains are found in Mesozoic formations in India. Most of the occurrences are in the central and southern India. The stratigraphic units that contain dinosaur fossils can perhaps be classified as follows:

• Jabalpur rocks of Central India -Most dinosaurs found here are from late Cretaceous rock beds.
• The Lameta Beds which lie below the Deccan Trap located in the southern states comprising of Andhra Pradesh, Tamil Nadu and Karnataka. This contains the most diverse and best known Indian fossils which mainly are from the Cretaceous.
  It is dominated by sauropods, like the Titanosaurus, Jainosaurus, Laplatasaurus and many Titanosaurid eggs and theropods such as Indosuchus, Indosaurus, Compsosuchus, Iubbulpuria, Laevisuchus, Dryptosauroides, Coeluroides and Ornithomimoides with a few omithischians like Lametasaurus and Brachypodosaurus.
• The Kota Formation of Gondwana Supergroup in Godavari Basin-Early Jurassic remains are confined largely to the Kota Formation. It also contains fossils of creatures such as Crossopterygians, Pterosaurs, Teleosairrids and Symmetrodonts. It contains a possible omithopod and two sauropods. Barapasaurus and Kotasaurus.
• The Trichinopoly and Ariyalur Formations in Cauvery Basin -Triassic deposits include the Mated Formation, which has yielded Temnospondyls, Rhynchosaurs, Phytosaurs, Cynodonts and the small theropod Alwalkeria, and the Dharmaram Formation which contains several unidentified dinosaurs including Iwo prosauropods.So much for distribution what happened to all the eggs that these dinosaurs produced?
  An Indian dinosaur natural site abounds with eggs that never hatched. Digging them out of their rocky graves some were found to be ellipsoidal while most were spheroidal ranging in diameter from l0 to 211cm.

Whose eggs were these? Well paleontologists have designated different names to them according to their structure. ‘Megaloolithus’ literally mean line eggs. These may have been the babies of Titanosaurus or others belonging to the same family. Elongatoolithus are generally assigned to treat eating dinosaurs – A third type of egg, much like the modem day hens’, was the Omithischian, but without any embryos within it is impossible to ascertain whether they belonged to small theropods or birds.

Ornthischian Egg

Shell Microstructure (Pathological Section of Dinosaur Egg)

Why was no little dinosaur, or developing embryo found within these eggs?
Well, no scientist can say for certain, except perhaps conjuncturing about the likely cause. Some say that the hatcheries may have been flooded drowning these unformed babies.

Still others add that perhaps these eggs were pathologically abnormal. How? Well, it seemed that they had exceedingly thick shells, which in all probability could not absorb oxygen. Thus the eggs could not develop. A third theory suggests that these were unfertilized eggs which were produced in large quantities.

Why were they unfertilized? Perhaps during the later stages the female population exceeded the male, progressively wiping out the entire population. But whatever the cause we need more research to conclusively prove anything!