Creatures that crossed the ocean to find India

India occupies a pivotal position in the distribution of life forms in Asia, Madagascar and Africa

India occupies a pivotal position in the distribution of life forms in Asia, Madagascar and Africa

You’ll likely see lemurs in a Hollywood animated movie; Singing, dancing and playing pranks. In the wild, it is found only on the island of Madagascar, which for naturalists has always been a place for interesting creatures.

Many life forms in Madagascar have links with lineages found in India (3800 km away) rather than Africa (413 km away). This has constituted a “difficult puzzle” for naturalists.

Zoologist Philip Sclater was baffled by the presence of lemurs, their relatives, and their fossils in Madagascar and India, but not in neighboring Africa or the Middle East. In the 1860s, it was suggested that a large island or continent must exist between India and Madagascar, to serve as a land bridge. Over time, this island sank. This proposed island was called Lemuria.

Sclatter’s hypothesis fascinated astrologers such as Helena Blavatsky, who believed that this place must be the now-lost place, where humans originated.

Tamil revivalists such as Devaneya Pavanar also embraced the idea, in the form of the Tamil civilization, which was lost at sea as described in literature and in Pandian myths. They called this submerged continent Kumari Kandam.

continental drift

Sclatter’s ideas lost a favourite when another “weird” theory, about continental drift, began to gain acceptance. In plate tectonics, the large rocky plates on which we stand float on molten subterranean rocks and move 2-15 cm per year relative to each other. A land mass called Gondwana, split in two 165 million years ago – one containing what is now Africa and South America, and the other containing India, Madagascar, Australia and Antarctica.

About 115 million years ago, Madagascar and India liberated together. About 88 million years ago, India moved north, dropping a few pieces of land along the way to form the Seychelles. It joined the Eurasian bloc 50 million years ago giving rise to the Himalayas and South Asia as we know it.

About 115 million years ago, dinosaurs ruled. Many life forms didn’t even evolve. To support the disintegration of Gondwana, dinosaur fossils found in India and Madagascar are closely related, not similar to species found in Africa and Asia. shards of Madagascar Laplatosaurus It is found in both India and Madagascar.

molecular watches

A powerful technology, the molecular clock, is used to estimate the time that the two life forms diverge from each other. It is based on the observation that evolutionary changes in the sequence of an RNA or protein molecule occur at a fairly constant rate. The difference in amino acids, for example, can tell you the hemoglobins of two animals since when their lineages diverged. Molecular clocks prove well with other evidence, such as the fossil record.

In southern India and Sri Lanka there are only two genera of the tilapia family of freshwater and saltwater fish – Etroplus (A food fish in Kerala, where it is called Balathi) And the pseudotroplus. Molecular comparisons show that the closest relatives of Etroplus are in Madagascar, and that their common ancestor diverged from the African tilapia 160 million years ago. The fourth group is in South America, therefore, it represents parts of Gondwana.

India’s pivotal location

India occupies a pivotal position in the distribution of life forms in Asia, Madagascar and Africa. Gondwana creatures moved from India. Others cross to stay. For example, Asian freshwater crabs ( Gecarcinucidae) are now found throughout Southeast Asia but their most recent common ancestor evolved in India. frog family Sooglossidaefound only in India and Seychelles (Datta-Roy and Karanth, Journal of Biological Sciences2009).

Fossil finds at the Vastan lignite mine in Gujarat have been made by researchers from HNB Garhwal, Punjab University and Johns Hopkins University, the first Indian mammal, a species of bat, and the closest euprimate, a primitive lemur. These have been dated 53 million years ago, around the time (or shortly before) the Indo-Eurasian plates collided ( Journal of the Paleontological Society of India2005).

What about lemurs? Madagascar is a large island, with a variety of climatic conditions. Evidence favors crossing primate ancestors from Africa. No monkey, ape, or large predator was able to manage the crossing, so dozens of species of lemur proliferated.

In India, we have lorises, which are the closest remaining relatives of lemurs. These are shy nocturnal forest dwellers, with large and attractive eyes. They are also believed to have survived ocean rides from Africa. They are mostly found in the northeastern states (slow loris), and where Karnataka, Kerala and Tamil Nadu (skinny loris) meet.

( The article was written in collaboration with Sushil Chandani who works in molecular modeling. [email protected])

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