Archive for the ‘Uncategorized’ Category

Recently our paper on the The phylogenetic position of Lepidopygopsis typus (Teleostei: Cyprinidae), a monotypic freshwater fish endemic to the Western Ghats of India has been published. This is an important work and a significant contribution to the Ichthyology of the Indian Peninsula, since it clears a longstanding misconception.

First of all, let me say that the species Lepidopygopsis typus a monotypic freshwater fish endemic to the Periyar Tiger Reserve (PTR) forests, is a relative of the Mahseers, and allied large barbs distributed in India, Pakistan, Afghanistan, Iran, Nepal and several North African regions.

It was until now confused to be a species within the “schizothoracinae”, which comprise the hill trouts or the mountain barbells of the Himalayas. The “disjunct distribution” has baffled ichthyologists and biogeographers at the same time.

Lepi

Now we show that it is just a case of a “false disjunct” which arose due to improper systematic position of the species.

Here, using phylogenetic hypothesis testing, and using both mitochondrial DNA and nuclear DNA phylogenies we solve the puzzle. All are welcome to read the paper and comment on it. If the readers need a full text of the paper please feel free to mail me or one of my co-authors who will happily share it with you for non-profit/research purposes.

 

Reference:

NEELESH DAHANUKAR, SIBY PHILIP, K. KRISHNAKUMAR, ANVAR ALI & RAJEEV RAGHAVAN, 2013. The phylogenetic position of Lepidopygopsis typus (Teleostei: Cyprinidae), a monotypic freshwater fish endemic to the Western Ghats of India, Zootaxa 3700 (1): 113–139.

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A recent publication.

Rajeev Raghavan, Siby Philip, Neelesh Dahanukar, Anvar Ali, 2013. Freshwater biodiversity of India: a response to Sarkar et al. (2013). Reviews in Fish Biology and Fisheries, DOI 10.1007/s11160-013-9315-9.

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.