title: Unraveling a 146 years old taxonomic puzzle: validation of Malabar snakehead, species-status and its relevance for channid systematics and evolution.
abstract: BACKGROUND
  The Malabar snakehead Channa diplogramma is one of the most enigmatic and least understood species within the family Channidae, which comprise one of the most important groups of freshwater food fish in tropical Asia. Since its description from peninsular India in 1865, it has remained a taxonomic puzzle with many researchers questioning its validity, based on its striking similarity with the South East Asian C. micropeltes. In this study, we assessed the identity of the Malabar snakehead, C. diplogramma, using morphological and molecular genetic analyses, and also evaluated its phylogenetic relationships and evolutionary biogeography.
  
  
  RESULTS
  The morphometric and meristic analysis provided conclusive evidence to separate C. diplogramma and C. micropeltes as two distinct species. Number of caudal fin rays, lateral line scales, scales below lateral line; total vertebrae, pre-anal length and body depth were the most prominent characters that can be used to differentiate both the species. Channa diplogramma also shows several ontogenic color phases during its life history, which is shared with C. micropeltes. Finally, the genetic distance between both species for the partial mitochondrial 16S rRNA and COI sequences is also well above the intra-specific genetic distances of any other channid species compared in this study.
  
  
  CONCLUSIONS
  The current distribution of C. diplogramma and C. micropeltes is best explained by vicariance. The significant variation in the key taxonomic characters and the results of the molecular marker analysis points towards an allopatric speciation event or vicariant divergence from a common ancestor, which molecular data suggests to have occurred as early as 21.76 million years ago. The resurrection of C. diplogramma from the synonymy of C. micropeltes has hence been confirmed 146 years after its initial description and 134 years after it was synonymised, establishing it is an endemic species of peninsular India and prioritizing its conservation value.
authors: Department of Zoology, Fatima Mata National College, Kollam, Kerala, India.
authors: Allen
authors: A
authors: Benziger
authors: Siby
authors: S
authors: Philip
authors: Rajeev
authors: R
authors: Raghavan
authors: Palakkaparambil Hamsa
authors: PH
authors: Anvar Ali
authors: Mithun
authors: M
authors: Sukumaran
authors: Josin C
authors: JC
authors: Tharian
authors: Neelesh
authors: N
authors: Dahanukar
authors: Fibin
authors: F
authors: Baby
authors: Reynold
authors: R
authors: Peter
authors: Karunakaran Rema
authors: KR
authors: Devi
authors: Kizhakke Veetil
authors: KV
authors: Radhakrishnan
authors: Mohamed Abdulkather
authors: MA
authors: Haniffa
authors: Ralf
authors: R
authors: Britz
authors: Agostinho
authors: A
authors: Antunes
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005399:Fishes / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics*; D014644:Genetic Variation; D005843:Geography; D007194:India; D008969:Molecular Sequence Data; D010802:Phylogeny; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D013045:Species Specificity; D013997:Time Factors