Monday, August 13, 2018

[Herpetology • 2018] Delineating Microhyla ornata (Anura, Microhylidae): Mitochondrial DNA Barcodes Resolve Century-old Taxonomic Misidentification

Microhyla mukhlesuri
Mmymensinghensis (Hasan et al. 2014)  

 M. nilphamariensis (Howlader et al. 2015)  
Microhyla ornata (Duméril & Bibron, 1841)

in Garg, Das, Kamei & Biju, 2018

Microhyla ornata, a species originally described from the southwest coast of India in 1841, was long reported to be wide-ranging throughout South, Southeast, and East Asia. Although the name M. ornata is restricted to populations from South Asia, the species is still considered to occur widely in India and its neighboring regions. To clarify the identity and geographical distribution of M. ‘ornata’, we performed DNA barcoding using a fragment of the mitochondrial 16S rRNA gene from 62 newly obtained samples. Our results show that this taxon is restricted to Peninsular India and Sri Lanka, whereas, populations from the other parts represent three different species – M. mukhlesuri, M. mymensinghensis, and M. nilphamariensis, creating new country records for India. Our work reemphasizes the benefits of DNA barcoding for rapidly identifying populations of widespread species and provides insights into the patterns of genetic differentiation in the M. ‘ornata’ species complex of South Asia. 

KEYWORDS: 16S; cryptic species; DNA barcoding; haplotype network; species distribution

Figure 1. DNA barcoding based on mitochondrial 16S rRNA gene sequences ( 540 bp). (A) Maximum Likelihood RAxML tree from total 145 newly sampled and previously available populations of Microhyla mukhlesuri, M. mymensinghensis, M. nilphamariensis, and M. ornata, along with sequences representing 24 other Microhyla species. Kaloula pulchra was used as the outgroup taxon. Bayesian Posterior Probabilities and RAxML bootstrap values >50% are indicated above and below the branches, respectively. Closed circles indicate samples from the present study; open circles indicate GenBank sequences. Geographical distribution of species is shown on the right panel. (B) Frequency distribution of intra- and interspecific sequence divergences for Microhyla mukhlesuri, M. mymensinghensis, M. nilphamariensis, and M. ornata, based on uncorrected and K2P pairwise distances.

Figure 2. Median-Joining haplotype network based on 147 mitochondrial 16S rRNA gene sequences from six closely related Microhyla species. Circle sizes are proportional to the number of haplotype sequences involved, as represented with numbers inside the circles. Black circles represent median vectors. Each branch represents one mutation step; black bars represent additional mutation steps. A schematic representation of species relationships with respect to geographical distribution is shown over the map.

Microhyla mukhlesuri, Mmymensinghensis (Hasan et al. 2014), 
M. nilphamariensis (Howlader et al. 2015) 
Microhyla ornata (Duméril & Bibron, 1841)

Sonali Garg, Abhijit Das, Rachunliu G. Kamei and S. D. Biju. 2018. Delineating Microhyla ornata (Anura, Microhylidae): Mitochondrial DNA Barcodes Resolve Century-old Taxonomic Misidentification.  Mitochondrial DNA Part B. 3:2; 856-861.  DOI: 10.1080/23802359.2018.1501286



Hasan M, Islam MM, Kuramoto M, Kurabayashi A, Sumida M. 2014. Description of two new species of Microhyla (Anura: Microhylidae) from Bangladesh. Zootaxa. 3755:401–418.  DOI: 10.11646/zootaxa.3755.5.1

Mohammad Sajid Ali Howlader, Abhilash Nair, Sujith V. Gopalan and Juha Merilä. 2015. A new species of Microhyla (Anura: Microhylidae) from Nilphamari, Bangladesh. PloS ONE. 10:e0119825. DOI:  10.1371/journal.pone.0119825