Posts Tagged ‘Western Ghats’

Recently our paper on the cryptic species among the red lined torpedo barbs (RLTB; Puntius denisonii and P. chalakkudiensis) have been published in plos one. The study identified 8 evolutionarily distinct lineages among the 12 different studied populations from its entire range.

At the molecular level, the study used mitochondrial DNA markers and employed species delimitation methods like the Bayesian Species delimitation method, the GMYC method etc, which identified 8 distinct lineages. At the morphological level CVA and MANOVA could distinguish all the populations as distinct.

However, taking into account both the results (from morphology and molecular methods), the minimum number of distinct lineages agreed by both methods is eight. Thus we conclude that the species has 8 distinct lineages that need separate conservation attention.

This study comes along with another study, which found that massive amounts of these barbs were being exported from India, after being collected from the wild. That means there are no regulations in India for the exploitation of this fish.

This fish is “endemic” to the Western Ghats of India. Now the finding that there are 8 distinct lineages that need separate conservation attention, calls for immediate action from the authorities, hobbyists and scientists, to generate an action plan and conserve this beautiful little fish.

Readers are invited to read this paper which is open access and downloadable at Plos One.

Reference:

John L, Philip S, Dahanukar N, Anvar Ali PH, Tharian J, Raghavan R., and Antunes A. (2013) Morphological and Genetic Evidence for Multiple Evolutionary Distinct Lineages in the Endangered and Commercially Exploited Red Lined Torpedo Barbs Endemic to the Western Ghats of India. PLoS ONE 8(7): e69741. doi:10.1371/journal.pone.0069741

A new catfish belonging to sisoridae – Pseudolaguvia lapillicola –  is described by Britz, Anvar and Raghavan. (link to the paper will be added here at a later stage).

This species was found along with Pangio ammophilaat Kumaradhara in southern Karnataka and was collected during their January-February 2012 explorations. As we know the eel-loach was “sand-loving” (hence the name), this species was found nearby (the sand) in the gravels – hence named lapillicolalapilli”=gravel andcolere“= dwell (or incola = resident, incolere = dwell [in]).

This species is yet another biogeographic puzzle. The relatives of this species, save one – Pseudolaguvia austrina, are all found in the North Eastern Indian region and in Myanmar (base of himalayas). In other words only one relative of this new species is found in the peninsular Indian region P. austrina from Bharathapuzha more southwards from Kumaradhara.

It is interesting that a similarly coloured (yellow brown background coloured) Glyptothorax  fish was found together (co-inhabiting or “co-incola” 🙂 ) at the same location, which looked like a Glyptothorax madraspatanum. It is also interesting that Pseudolaguvia austrina from Bharathapuzha was found to co-inhabit with Glyptothorax anamalensis (Anvar Ali personal comm.). Remember that Glyptothorax and Pseudolaguvia both belong to Sisoridae (Family) and these genera are found living together at least in more than one location (according to the authors, it smells fishy!!!!).

What was the adaptive trajectory that these similar looking (and sized) fishes took to co-exist in a similar habitat,  lot of work (for the authors) to follow up with.

Biogeographic Puzzle?

These same set of authors have found two other species recently, Pangio ammophila which has all its closest relatives in the South East Asian Region, and Dario urops  which has all its relatives in North Eastern (NE) India, Myanmar and South East (SE) Asia.

This has been a hot topic of research during the past, not only these – but many other species like Lepidopygopsis typus (relatives in Himalayas and Central Asia), Pterocryptis wynaadensis (relatives in NE India, China etc.), which show this kind of distribution are known – albeit rare. For a better treatment on this subject (discontinuous distribution) readers are advised to read the paper available in this link.

Till recently it was thought to be a rarity to find a species with its congener’s in distant places like NE India (through) SE Asia. But, nowadays we hear it a lot, Dario, Pangio, Pseudolaguvia etc. from the Western Ghats. What does this say?

The species mentioned here (and also listed in the above links) have common ancestry. That means Pangio’s  form WG and SE Asia have a common ancestry, Dario from WG and Dario’s and Badises from SEAsia have a common ancestry, Pseudolaguvia from WG and NE India and SE Asia have a common ancestry. So again – what does it say?

All these regions (geographical regions) have a common ancestry.  Easily said but not well understood.

These zoological explorations are thus shedding light on different aspects of the formation of a region and formation of the biodiversity seen there. We need more such explorations and studies to understand this remarkable evolutionary process. Evolution of the continents, evolution of the taxa and the dispersal and distribution of organisms.

Another thing to be noted here is that more and more cases of discontinuous distribution (of species) are found “now” simply because – people explore nature more (than in the past) – for example these guys found because they looked, more such examples and species may be there “unknown” in the WG and more people are needed to study nature!!

Reference:

Britz, R., Ali, A. & R. Raghavan. (2013). Pseudolaguvia lapillicola, a new species of catfish from Peninsular India (Teleostei: Sisoridae). Ichthyological Exploration of Freshwaters, 23: 289-295.

NB: [competing interests] I assisted the authors in their field work.