Delimiting cryptic species within the brown-banded bamboo shark, Chiloscyllium punctatum in the Indo-Australian region with mitochondrial DNA and genome-wide SNP approaches

Background Delimiting cryptic species in elasmobranchs is a major
challenge in modern taxonomy due the lack of available phenotypic
features. Employing stand-alone genetics in splitting a cryptic species
may prove problematic for further studies and for implementing
conservation management. In this study, we examined mitochondrial DNA and
genome-wide nuclear single nucleotide polymorphisms (SNPs) in the
brown-banded bambooshark, Chiloscyllium punctatum to evaluate potential
cryptic species and the species-population boundary in the group. Results
Both mtDNA and SNP analyses showed potential delimitation within C.
punctatum from the Indo-Australian region and consisted of four
operational taxonomic units (OTUs), i.e. those from Indo-Malay region, the
west coast of Sumatra, Lesser Sunda region, and the Australian region.
Each OTU can be interpreted differently depending on available supporting
information, either based on biological, ecological or geographical data.
We found that SNP data provided more robust results than mtDNA data in
determining the boundary between population and cryptic species.
Conclusion To split a cryptic species complex and erect new species based
purely on the results of genetic analyses is not recommended. The
designation of new species needs supportive diagnostic morphological
characters that allow for species recognition, as an inability to
recognise individuals in the field creates difficulties for future
research, management for conservation and fisheries purposes.
 Moreover, we recommend that future studies use a comprehensive
sampling regime that encompasses the full range of a species complex. This
approach would increase the likelihood of identification of operational
taxonomic units rather than resulting in an incorrect designation of new
species.