Study on carnivorous fish of Sri Lanka

Channa orientalis also known as the Ceylon snakehead is the only pelvic-fin less snakehead in Sri Lanka.

by Ifham Nizam

A team of ichthyologists in their latest study on carnivorous fish of Sri Lanka points out that Channa orientalis also known as the Ceylon snakehead, is the only pelvic-fin less snakehead in Sri Lanka.

Snakeheads are one of the main carnivorous groups of freshwater fish in Sri Lanka. They belong to the family Channidae and the genus Channa. There are six species of Channa in Sri Lanka, two of which are endemic. The two endemic species are Channa ara and Channa orientalis. Channa orientalis also known as the Ceylon snakehead is the only pelvic-fin less snakehead in Sri Lanka.

The latest study on the genetic diversity and morphological stasis in the Ceylon Snakehead found that the taxonomic identity and the type locality of this species were not certain.

Scientist Hiranya Sudasinghe told The Island yesterday: “We show that C. orientalis is composed of two geographically and genetically distinct lineages but which show remarkable morphological similarity between the two lineages. The recognition of two distinct genetic lineages is important because, when it comes to conservation management of this species, these two lineages could be recognised as two Evolutionary Significant Units that would deserve separate conservation attention.”

“We argue that the type locality of C. orientalis is south-western Sri Lanka, to which the species is endemic. Channa orientalis is distinguished from other species of Channa by the absence of pelvic fins, adult colouration in life, dorsal- and anal-fin ray counts, number of vertebrae, and scale counts,” the team pointed out.

This species feeds like a ciclids, experts point out.

The team of scientists comprises of Hiranya Sudasinghe of Evolutionary Ecology and Systematics Lab, Department of Molecular Biology and Biotechnology, University of Peradeniya, Peradeniya, Sri Lanka/ Postgraduate Institute of Science, University of Peradeniya, Peradeniya, SriLanka, R.H.Tharindu Ranasinghe of Butterfly Conservation Society of Sri Lanka, Rohan Pethiyagoda of  Ichthyology Section, Australian Museum, 1 William Street, Sydney, NSW 2010, Australia, Madhava Meegaskumbura of  Guangxi Key Laboratory of Forest Ecology & Conservation, College of Forestry, Guangxi University, Nanning, People’s Republic of China and Ralf Britz Senckenberg Naturhistorische Sammlungen Dresden, Museum für Tierkunde, Königsbrücker Landstrasse 159, 01109 Dresden, Germany

As the type species of the genus Channa, the identity of the pelvic-finless snakehead Channa orientalis Bloch is important to channid systematics. Although this name has been attached to a Sri Lankan species for the past 160 years, its vaguely specified type locality, ‘India Orientali’, has long cast doubt as to its origin.

Based on a collection across its range in the island and analysis of the cytochrome c oxidase subunit 1 (cox1) barcoding gene, scientists show that the Sri Lankan pelvic-finless Channa is composed of two geographically discrete lineages separated by an uncorrected pairwise cox1 genetic distance of 6.9–8.1%.

The minimum genetic distance between these two lineages and other species of the Gachua group of Channa is 5.1%. Despite their genetic divergence, the two lineages exhibit remarkable morphological stasis: they are indistinguishable from each other in external morphology.