DNA barcoding elucidates the population genetic diversity of venomous cobra species (Reptilia: Elapidae) in Indo-Bangladesh region

Abstract

The DNA barcode data of venomous cobra species (Naja naja and Naja kaouthia) are limited in the global database, especially from India and Bangladesh. Owing to the rapid success of DNA barcoding for discriminating a variety of species around the world, the present study aimed to generate the mitochondrial cytochrome c oxidase subunit I (COI) gene information of two morphologically identified deadly elapid species from the Mizoram state in northeast India and Rangpur in northern Bangladesh. The multiple species delimitation methods: Automatic Barcode Gap Discovery (ABGD), General Mixed Yule-Coalescent (GMYC), and Poisson-Tree-Processes (bPTP) revealed 14, 16, and 18 molecular operational taxonomic units (MOTUs) for 12 Naja species. The binocellate cobra, N. naja showed monophyletic clustering in both maximum-likelihood (ML) and Bayesian (BA) trees, single MOTU in ABGD and GMYC, and negligible intra-species genetic distance (0.2%) with two haplotypes. However, the monocellate cobra, N. kaouthia showed paraphyletic and polytomy in ML and BA phylogenies respectively; more than one MOTUs in ABGD, GMYC, and bPTP analyses; and sufficient intra-species genetic distances (0.6-2.3%) with five haplotypes related to the diverse geographical locations in Bangladesh, China, India, and Thailand. By superimposing the executed species delimitation criteria, the present molecularbased investigation concludes the presence of cryptic diversity of N. kaouthia in Indo-Bangladesh, China, and Thailand.

Description of a New Cobra (Naja Laurenti, 1768; Squamata, Elapidae) from China with Designation of a Neotype for Naja atra

“…Present samples of Naja kaouthia from the South Asian population and Southeast Asian population form sister clades. Since the type locality of N. kaouthia is the Bengal region [ 57 ], those specimens from northeastern India, Bangladesh and adjacent areas including Bhutan, Nepal, and southern Tibet Autonomous Region, China should be treated as N. kaouthia sensu stricto [ 5 , 26 , 27 , 28 , 29 ]. The following diagnoses of N. kaouthia are based on data from South Asia, including data of 13 preserved specimens and 32 living individuals.…”

“…Measurements and scale counts of three adult females and one adult male were cited from Lalremsanga et al [ 58 ]. Data of living individuals were based on photos of from literatures [ 28 , 32 , 59 , 60 ], personal collections of Vogel Gernot and Vivek R Sharma, and GBIF.com) ( Supplementary Table S2 ).…”

“…The Monocled Cobra, Naja kaouthia , is widely recorded in northeastern India, Bangladesh, Bhutan, Nepal, Myanmar, Cambodia, Laos, Northern Malaysia, Southern Vietnam, Thailand and southern China [ 25 ] and was firstly described from Bengal by Lesson (1831). However, recent research implied that considerable diversification has occurred among different geographical populations (China, Thailand and Bangladesh) of this species [ 5 , 26 , 27 , 28 , 29 ]. Multiple variations among populations of N. kaouthia regarding coloration, spitting behavior and especially venom toxin composition were found; the venom of the Yunnan population of N. kaouthia lacks α-cobratoxin while that of the Thailand population has it [ 3 , 4 , 5 , 6 ].…”

“…Morphological comparisons for 13 taxa of Asian cobras subgenus Naja based on selected characters. References [ 12 , 14 , 17 , 18 , 28 , 32 , 51 , 56 , 58 , 59 , 60 , 64 , 69 , 70 ] are cited in the supplementary materials.…”