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International study reveals a much higher species diversity of snakehead fishes than previously thought

Snakehead fishes are predatory ray-finned fishes belonging to the family Channidae. Found across Asia and Africa, snakehead fishes are important sources of food, and are widely cultivated by humans. Snakehead fishes are known survive on wet land for up to 4 days, and are considered to be a highly invasive species, with a single snakehead female capable of laying up to 150,000 eggs in just a span of two years. So far, 38 valid species of snakeheads had been recognised. Most of these snakehead species demarcations are based on genetic barcodes, which are specific regions or loci within the snakehead genome that uniquely differ for each of the known snakehead species. However, the scientific literature on snakehead taxonomy is filled with a lot of confusing and contradictory information. Further, the fact that snakeheads are known to exhibit striking changes in colour pattern throughout their growth stages, from larval to juvenile to adult stages, makes their correct identification and classification even more difficult. Now, a recent international collaboration, scientists from India, United Kingdom, Switzerland, Australia, Singapore, Malaysia and Indonesia, have conducted an in-depth analysis of existing snakehead fish species, to try and clarify this taxonomic confusion. The scientists used various different species classification approaches to rectify various misidentifications and incorrect classification of these snakehead fishes. Their study found that the total number of snakehead species was much higher (at least 53) than what was previously believed (38). The team also discovered six previously undescribed species of snakeheads, all within the Eastern Himalayan regions of India and Myanmar, and another additional one in Congo. Further, they classified eight more putative species that had been previously observed, but were mistakenly grouped under other existing snakehead species. Given the importance of the fish species as large-scale sources of food, as well as the ecological implications of introducing them in non-native environments, a good understanding of snakehead taxonomy and classification is crucial. This study is an important step in that direction, as it helps clarify existing taxonomic confusions, and can serve as a fresh reference point for all future snakehead studies.