As per news reports in October 2020, a new type of fish was found in underground rocks of state after a social media post made a researcher in Kerala curious. Scientists have named it Aenigmachanna gollum after the dark and conflicted character of JRR Tolkien’s epic saga ‘Lord of the Rings’. It looks like a dragon, swims like an eel and has remarned hidden for a hundred million years. Ultimately, found in an area which is part of the Western Ghats-Sri Lanka Hotspot-among the richest biodiversity hotspots in the world. Ten other species of subterranean fish have been discovered in the aquifers.
The species belongs to an old family of fish, called dragon snakeheads, and retains its primitive characteristics even after all so long a period. They hold a prominent role for our understanding of the diversification of the group in question. Besides it, a sister species has also been discovered, called Aenigmachanna mahabali, one of the most exciting discovery in the world. They could evade scientists because of living in subterranean aquifers. They come to the surface only after heavy floods.
Channidae is the closest relative of the family Aenigmachannidae, of which at least 50 species can be found in the streams and lakes of Asia and tropical Africa. According to molecular analyses, the two families split from each other about 34 to 109 million years ago. It indicates that Aenigmachanna is a Gondwanan lineage, which survived break-up of the supercontinent and was separated from Africa at about 120 million years ago.
Relic from Ancient Time: Its shortened swim bladder and fewer vertebrae with ribs show the lack of evolution and indicate that the family is less specialised than regular snakeheads. It has eyes and reddish-brown pigmentation; an unusual feature as most subterranean fishes do not have eyes and are pale. The Aenigmachannidae also lacks the suprabranchial organ that allows the Channidae to breathe air and proliferate widely.
Reason for Their Endemism: Recent radiations have not only resulted in its high levels of endemism, a number of other ancient lineages have also been suffered. There are a number of such relic lineages in the Western Ghats among vertebrates with unclear phylogenetic relationships like the cyprinid Lepidopygopsis and the catfish Kryptoglanis, or with remote biogeographical connections, such as the burrowing frog Nasikabatrachus.
————Sidelight————
The term living taxa refers to a few extant species of seemingly endless animal life on our planet, which hold a unique position for our understanding of the evolution of the group to which they belong. Such taxa, previously known as ‘living fossil’ have been referred to as ‘basal taxa’ as they exhibit a striking level of morphological stasis, evidenced by a surprisingly large number of primitive characters, compared to their extant sister group. Such taxa often represent lineages with only few extant representatives and a limited distribution.
Courtesy: Indian Express