India at the cross-roads of human evolution

Abstract

The Indian palaeoanthropological record, although patchy at the moment, is improving rapidly with every new find. This broad review attempts to provide an account of (a) the Late Miocene fossil apes and their gradual disappearance due to ecological shift from forest dominated to grassland dominated ecosystem around 9-8 Ma ago, (b) the Pliocene immigration/evolution of possible hominids and associated fauna, (c) the Pleistocene record of fossil hominins, associated fauna and artifacts, and (d) the Holocene time of permanent settlements and the genetic data from various human cultural groups within India. Around 13 Ma ago (late Middle Miocene) Siwalik forests saw the emergence of an orangutan-like primate Sivapithecus. By 8 Ma, this genus disappeared from the Siwalik region as its habitat started shrinking due to increased aridity influenced by global cooling and monsoon intensification. A contemporary and a close relative of Sivapithecus, Gigantopithecus (Indopithecus), the largest ape that ever-lived, made its first appearance at around 9 Ma. Other smaller primates that were pene-contemporaneous with these apes were Pliopithecus (Dendropithecus), Indraloris, Sivaladapis and Palaeotupia. The Late Pliocene and Early Pleistocene witnessed northern hemisphere glaciations, followed by the spread of arid conditions on a global scale, setting the stage for hominids to explore "Savanahastan". With the prominent expansion of grassland environments from East Africa to China and Indonesia in the Pliocene, monkeys and baboons dispersed into the Indian subcontinent from Africa along with other mammals. Though debated, there are several claims of the presence of early hominins in this part of the world during the Late Pliocene, based primarily on the recovery of Palaeolithic tools. Fossils of our own ancestor and one of the first globe-trotters, early Homo erectus, has been documented from the Early Pleistocene of East Africa, Western Asia and Southeast Asia, thus indirectly pointing towards Indian subcontinent as a possible migration corridor between these regions. The only definite pre-Homo sapiens fossil hominin remains come from the Central Narmada Valley and are thought to be of Middle to late Pleistocene age, and the cranium has been shown to be closely linked to archaic Homo sapiens/H. heidelbergensis of Europe. Around approximately 74,000 yrs ago, a super volcanic eruption in Sumatra caused the deposition of Youngest Toba Tephra, that covered large parts of the Indian peninsula. Just around this time anatomically-and-behaviorally modern humans or Homo sapiens possibly arrived into India as evidenced by the so called Middle and Upper Palaeolithic assemblages and associated symbolic evidence. The available genetic data reveals that the gene pool to which modern Indians races belong was extremely diverse and had variable mixed links with both European and Asian populations.

Not by science alone: why orangutan conservationists must think outside the box

“…The dramatic environmental changes that occurred in Asia from the late Miocene to the Pleistocene probably contributed to the extinction of many of the Asian apes 6 and may have substantially reduced orangutan population sizes as well. Broadly speaking, climatic changes such as increased aridity, more intense monsoons, and increased frequency and severity of glacial‐inter‐glacial cycles caused once widespread evergreen rainforests, the habitat of orangutans, to be increasingly restricted to isolated pockets close to the equator 7, 8 …”

“…Broadly speaking, climatic changes such as increased aridity, more intense monsoons, and increased frequency and severity of glacial-inter-glacial cycles caused once widespread evergreen rainforests, the habitat of orangutans, to be increasingly restricted to isolated pockets close to the equator. 7,8 The genus Pongo could be found until the Late Pleistocene, or some 40,000 years ago, from as far north of southern China to the island of Java. 9,10 The present habitat of the Sumatran Orangutan (Pongo abelii) and Bornean Orangutan (P. pygmaeus) is probably less than 5% of the original Pongo distribution range.…”

Genetic Affinities of the Central Indian Tribal Populations

“…As this state is a shelter for three different language groups, it can help to test several language-gene interaction models. The archaeological studies also suggest that Narmada region has played a vital role in initial peopling of the subcontinent [11], [12]. Considering its central role in shaping the major episodes of peopling of South Asia, a detailed study on the populations of this important state is necessary.…”

Genomic view on the peopling of India

“…The stone tools of this study most likely resemble contemporaneous Homo sapiens technologies in Africa. Further, a partial cranium recovered from Narmada Basin was dated back to around 300,000 to 250,000 YBP [11,12]. Over the past two decades, several independent studies have been carried out in various Indian populations with ancient and modern DNA using haploid and diploid markers.…”