Khursheed Dinshaw (India)
In the first part of this article (see Siwalik Fossil Park, Himachal Pradesh State, India: Part 2), I introduced Siwalik Fossil Park, its geology and some of the animals and plants whose fossilised remains have been found there. In this second and last part, I cover some more of the mega fauna that once lived here. In fact, the Siwalik Fossil Park, in the state of Himachal Pradesh, India is a significant step towards the preservation of prehistoric animal sites, conserving and repairing the current natural environment and utilising them for scientific and educational purposes. In fact, the park is a rich geological heritage.
The environment and climate was highly favourable for the development of elephants in the Siwalik region between 20 and 1.5mya (Figs. 1 and 2). Approximately 22 fossil species have been found, but all became extinct one million years ago with the beginning of the Ice Age.
Nowadays, only one species is found in India (the Indian elephant, Elephas maximus indicus). The fossil skulls, jaws, teeth and bones of extinct species are displayed at the museum along with a life-size fibre glass model of the extinct giant species, Stegodon ganesa (Figs. 3 and 4).
Of the species that existed during the Plio-Pleistocene period, S. ganesa attained the greatest size. This elephant possessed a relatively small cranium, an extraordinarily large pair of tusks (which were 4m to 5m long), a heavy trunk and massive limb bones.
Dr VP Mishra, Deputy Director General (Retd) at the Geological Survey of India, who was instrumental in setting up the Siwalik Fossil Park, adds:
The fossil skulls and mandibles of elephant include maxillary fragment with the first molar and isolated well preserved upper molar containing 11 plates, a skull of a juvenile embedded in hard rock matrix with its dentition on both sides preserved. Its milk [tooth] M2 is averagely worn out while its milk M3 is in the emerging stage. Broken roots of the tusk can be seen. The milk [tooth] M2 on both sides contains eight or nine plates.”
Other exhibits of elephants include a cranium with a second molar on each side of the jaw (Fig. 5), part of maxilla with second and third milk molars, a partial skull containing dentitions on both sides and palate, with intact second and third milk molars on both sides.
There are teeth fragments of fossilised elephants, including isolated upper molar teeth and fragments, and isolated lower molar teeth fragments (Fig. 6).
Elephants have large grinding molar teeth, which chew and grind their plant diet with a backward-forward jaw action. These teeth fall out when worn down and are replaced by new, larger teeth. During its lifetime, an elephant may grow 24 of these large molar teeth, each weighing up to 4kg in older animals. Only four teeth, two of each side of the jaw are in use at a time. As the teeth wear down, they move forward and the new teeth grow behind, with the worn teeth ultimately dropping out. This pattern repeats up to six times in an elephant’s lifetime. In fact, the most common method of determining an elephant’s age is by examining their teeth and jaw. Once all the teeth have fallen out, an elephant can no longer chew food and will die soon after of starvation.
Elephant tusks are actually elongated second incisors, which grow continuously. The exhibits at the museum include a tusk fragment, which is broken from the base and its apex is pointed. It is about 60cm long. The other exhibit is a well-preserved large tusk of about 1.2m in length, but is broken on both ends.
Presently, giraffes are not found in India, but the fossils of four genera have been found in the Siwalik rocks (Fig. 7).
Ancestors of giraffe inhabited this region and evolved along diverse lines during the Plio-Pleistocene period. One of them, Sivatherium giganteum, was a large four-horned giraffe, with an extraordinarily heavy skull and a relatively short neck in comparison to modern giraffes. Indeed, it was a very interesting, giant-sized, queer-looking giraffe, standing four metres in height, with enormous horns fixed on its massive skull. The male had four horns, with an anterior conical pair arising from the frontals and a posterior pair. The species became extinct along with its kin about 1.5mya.
Dr Mishra explains:
Fossils of the giraffe have been recovered in the form of jaws, teeth, bones and ossicones. Ossicones are the horn-like or antler-like protuberance on the heads of giraffes. They were derived from ossified cartilage and the ossicones remained covered in skin and fur.”
Fossils include isolated upper molars, ossicone fragments, maxillary fragment with a second and third molar, left ramus fragment with a third molar. There is also a fibre glass model of a giraffe in the park.
Abundant fossils of animals belonging to the bovid family occur in the Siwalik hills and its adjacent areas. In bovids, the size and shape of the horns vary greatly, but the basic structure is almost similar. They have one or more pairs of simple, bony protrusions without branches, which often have a spiral, twisted or fluted form. Each is covered in a permanent sheath of keratin. The displays inside the museum include bovid skulls, jaws, teeth, horn cores and bones. I was lucky enough to have Shiv Charan, the museum guide, take me around personally to show me these remains. Shiv is a local from the region, who has been passionate about the fossils of Siwalik for the last 40 years (Fig. 8).
I hope I have shown you that the Siwalik Fossil Park is a valuable heritage showcasing the fossils and rocks of the area. For me, to see the beautifully preserved and presented exhibits, and learn about them through the guide, information boards and placards, is an experience that I will cherish for a long time.